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Spasojevic, Ivan

Positions:

Associate Professor in Medicine

Medicine, Medical Oncology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

Ph.D. 1999

Ph.D. — Duke University

Grants:

Role of GLUD2 as a metabolic driver of gliomas with IDH1 mutations

Administered By
Pathology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
September 30, 2016
End Date
June 30, 2021

The Role of IDH1 Mutations in Gliomagenesis and Metabolism

Administered By
Pathology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
July 01, 2009
End Date
March 31, 2020

Effect of Aging on Brain Ischemia/Stroke Outcome; Pathways, Mechanisms, and Rescue

Administered By
Anesthesiology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
July 01, 2016
End Date
June 30, 2019

Measurement of oxidative stress biomarkers in human plasma and urine

Administered By
Duke Cancer Institute
AwardedBy
University of California - Berkeley
Role
Principal Investigator
Start Date
June 01, 2016
End Date
September 30, 2018

Development of mechanistically distinct androgen receptor antagonists and degraders for the treatment of advanced castra

Administered By
Pharmacology & Cancer Biology
AwardedBy
Department of Defense
Role
Facility Mgr.
Start Date
September 30, 2015
End Date
September 29, 2018

New therapeutic strategy in reversing radiation-induced erectile dysfunction with prostate cancer pa-tients

Administered By
Radiation Oncology
AwardedBy
North Carolina Biotechnology Center
Role
Co Investigator
Start Date
January 18, 2016
End Date
January 17, 2017

Treatment of Neuropathic Pain after SCI with a Catalytic Oxidoreductant

Administered By
Anesthesiology
AwardedBy
University of Alabama at Birmingham
Role
Co Investigator
Start Date
September 30, 2013
End Date
September 29, 2016

Fe porphyrin-based Redox Modulator in Experimental Stroke Outcome

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
April 01, 2013
End Date
March 31, 2015

Biomarker Studies for Novel Anti-Cancer Agents

Administered By
Medicine, Medical Oncology
AwardedBy
National Institutes of Health
Role
Research Associate
Start Date
May 28, 2003
End Date
February 29, 2008
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Publications:

Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine

Authors
Božić, B; Korać, J; Stanković, DM; Stanić, M; Popović-Bijelić, A; Bogdanović Pristov, J; Spasojević, I; Bajčetić, M
MLA Citation
Božić, B, Korać, J, Stanković, DM, Stanić, M, Popović-Bijelić, A, Bogdanović Pristov, J, Spasojević, I, and Bajčetić, M. "Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine." Chemico-Biological Interactions 278 (December 2017): 129-134.
Source
crossref
Published In
Chemico-Biological Interactions
Volume
278
Publish Date
2017
Start Page
129
End Page
134
DOI
10.1016/j.cbi.2017.10.022

Apple pectin-derived oligosaccharides produce carbon dioxide radical anion in Fenton reaction and prevent growth of Escherichia coli and Staphylococcus aureus

Authors
Martinov, J; Krstić, M; Spasić, S; Miletić, S; Stefanović-Kojić, J; Nikolić-Kokić, A; Blagojević, D; Spasojević, I; Spasić, MB
MLA Citation
Martinov, J, Krstić, M, Spasić, S, Miletić, S, Stefanović-Kojić, J, Nikolić-Kokić, A, Blagojević, D, Spasojević, I, and Spasić, MB. "Apple pectin-derived oligosaccharides produce carbon dioxide radical anion in Fenton reaction and prevent growth of Escherichia coli and Staphylococcus aureus." Food Research International 100 (October 2017): 132-136.
Source
crossref
Published In
Food Research International
Volume
100
Publish Date
2017
Start Page
132
End Page
136
DOI
10.1016/j.foodres.2017.08.040

Niclosamide-conjugated polypeptide nanoparticles inhibit Wnt signaling and colon cancer growth.

Abnormal Wnt activity is a major mechanism responsible for many diseases, including cancer. Previously, we reported that the anthelmintic drug Niclosamide (NIC) inhibits Wnt/β-catenin signaling and suppresses colon cancer cell growth. Although the pharmacokinetic properties of NIC are appropriate for use as an anthelmintic agent, its low solubility, low bioavailability and low systemic exposure limit its usefulness in treating systemic diseases. To overcome these limitations, we conjugated NIC to recombinant chimeric polypeptides (CPs), and the CP-NIC conjugate spontaneously self-assembled into sub-100 nm near-monodisperse nanoparticles. CP-NIC nanoparticles delivered intravenously act as a pro-drug of NIC to dramatically increase exposure of NIC compared to dosing with free NIC. CP-NIC improved anti-tumor activity compared to NIC in a xenograft model of human colon cancer. Because NIC has multiple biological activities, CP-NIC could be used for treatment of multiple diseases, including cancer, bacterial and viral infection, type II diabetes, NASH and NAFLD.

Authors
Bhattacharyya, J; Ren, X-R; Mook, RA; Wang, J; Spasojevic, I; Premont, RT; Li, X; Chilkoti, A; Chen, W
MLA Citation
Bhattacharyya, J, Ren, X-R, Mook, RA, Wang, J, Spasojevic, I, Premont, RT, Li, X, Chilkoti, A, and Chen, W. "Niclosamide-conjugated polypeptide nanoparticles inhibit Wnt signaling and colon cancer growth." Nanoscale 9.34 (August 22, 2017): 12709-12717.
PMID
28828438
Source
epmc
Published In
Nanoscale
Volume
9
Issue
34
Publish Date
2017
Start Page
12709
End Page
12717
DOI
10.1039/c7nr01973d

CNS bioavailability and radiation protection of normal hippocampal neurogenesis by a lipophilic Mn porphyrin-based superoxide dismutase mimic, MnTnBuOE-2-PyP5.

Although radiation therapy can be effective against cancer, potential damage to normal tissues limits the amount that can be safely administered. In central nervous system (CNS), radiation damage to normal tissues is presented, in part, as suppressed hippocampal neurogenesis and impaired cognitive functions. Mn porphyrin (MnP)-based redox active drugs have demonstrated differential effects on cancer and normal tissues in experimental animals that lead to protection of normal tissues and radio- and chemo-sensitization of cancers. To test the efficacy of MnPs in CNS radioprotection, we first examined the tissue levels of three different MnPs - MnTE-2-PyP5+(MnE), MnTnHex-2-PyP5+(MnHex), and MnTnBuOE-2-PyP5+(MnBuOE). Nanomolar concentrations of MnHex and MnBuOE were detected in various brain regions after daily subcutaneous administration, and MnBuOE was well tolerated at a daily dose of 3mg/kg. Administration of MnBuOE for one week before cranial irradiation and continued for one week afterwards supported production and long-term survival of newborn neurons in the hippocampal dentate gyrus. MnP-driven S-glutathionylation in cortex and hippocampus showed differential responses to MnP administration and radiation in these two brain regions. A better understanding of how preserved hippocampal neurogenesis correlates with cognitive functions following cranial irradiation will be helpful in designing better MnP-based radioprotection strategies.

Authors
Leu, D; Spasojevic, I; Nguyen, H; Deng, B; Tovmasyan, A; Weitner, T; Sampaio, RS; Batinic-Haberle, I; Huang, T-T
MLA Citation
Leu, D, Spasojevic, I, Nguyen, H, Deng, B, Tovmasyan, A, Weitner, T, Sampaio, RS, Batinic-Haberle, I, and Huang, T-T. "CNS bioavailability and radiation protection of normal hippocampal neurogenesis by a lipophilic Mn porphyrin-based superoxide dismutase mimic, MnTnBuOE-2-PyP5." Redox biology 12 (August 2017): 864-871.
PMID
28454069
Source
epmc
Published In
Redox Biology
Volume
12
Publish Date
2017
Start Page
864
End Page
871
DOI
10.1016/j.redox.2017.04.027

Potential for a novel manganese porphyrin compound as adjuvant canine lymphoma therapy.

Manganese porphyrins are redox-active drugs and superoxide dismutase mimics, which have been shown to chemosensitize lymphoma, a cancer which frequently occurs in dogs. This study aimed to identify critical information regarding the pharmacokinetics and toxicity of Mn(III) meso-tetrakis (N-n-butoxyetylpyridium-2-yl) porphyrin, (MnTnBuOE-2-PyP5+, MnBuOE) in dogs as a prelude to a clinical trial in canine lymphoma patients.A single-dose pharmacokinetic (PK) study in normal dogs was performed to determine the plasma half-life (t 1/2) of MnBuOE. A dose reduction study was performed to establish the maximum tolerated dose (MTD) of MnBuOE. The safety and PK of a multi-dosing protocol was assessed.Peak plasma drug concentration occurred 30 min post-injection. The t 1/2 was defined as 7 h. MnBuOE induced an anaphylactic reaction and prolonged tachycardia. The MTD was defined as 0.25 mg/kg. The dogs were given MTD 3×/week for 2-3 weeks. The highest recorded tissue drug levels were in the lymph nodes (4-6 μM), followed by kidney and liver (2.5, 2.0 uM, respectively).We obtained critical information regarding the PK and toxicity of MnBuOE in dogs. The acute drug reaction and tachycardia post-injection have not been described in other species and may be specific to canines. The high tissue drug levels in lymph nodes have not been previously reported. MnBuOE accumulation in lymph nodes has important implications for the utility of adjuvant MnBuOE to treat lymphoma. With MnBuOE lymph node accumulation, reduction in the dose and/or administration frequency could be possible, leading to reduced toxicity.

Authors
Boss, MK; Dewhirst, MW; Sampaio, RS; Bennett, A; Tovmasyan, A; Berman, KG; Beaven, AW; Rizzieri, DA; Batinic-Haberle, I; Hauck, ML; Spasojevic, I
MLA Citation
Boss, MK, Dewhirst, MW, Sampaio, RS, Bennett, A, Tovmasyan, A, Berman, KG, Beaven, AW, Rizzieri, DA, Batinic-Haberle, I, Hauck, ML, and Spasojevic, I. "Potential for a novel manganese porphyrin compound as adjuvant canine lymphoma therapy." Cancer chemotherapy and pharmacology 80.2 (August 2017): 421-431.
PMID
28685347
Source
epmc
Published In
Cancer Chemotherapy and Pharmacology
Volume
80
Issue
2
Publish Date
2017
Start Page
421
End Page
431
DOI
10.1007/s00280-017-3372-z

Cystine addiction of triple-negative breast cancer associated with EMT augmented death signaling.

Despite the advances in the diagnosis and treatment of breast cancer, breast cancers still cause significant mortality. For some patients, especially those with triple-negative breast cancer, current treatments continue to be limited and ineffective. Therefore, there remains an unmet need for a novel therapeutic approach. One potential strategy is to target the altered metabolic state that is rewired by oncogenic transformation. Specifically, this rewiring may render certain outside nutrients indispensable. To identify such a nutrient, we performed a nutrigenetic screen by removing individual amino acids to identify possible addictions across a panel of breast cancer cells. This screen revealed that cystine deprivation triggered rapid programmed necrosis, but not apoptosis, in the basal-type breast cancer cells mostly seen in TNBC tumors. In contrast, luminal-type breast cancer cells are cystine-independent and exhibit little death during cystine deprivation. The cystine addiction phenotype is associated with a higher level of cystine-deprivation signatures noted in the basal type breast cancer cells and tumors. We found that the cystine-addicted breast cancer cells and tumors have strong activation of TNFα and MEKK4-p38-Noxa pathways that render them susceptible to cystine deprivation-induced necrosis. Consistent with this model, silencing of TNFα and MEKK4 dramatically reduces cystine-deprived death. In addition, the cystine addiction phenotype can be abrogated in the cystine-addictive cells by miR-200c, which converts the mesenchymal-like cells to adopt epithelial features. Conversely, the introduction of inducers of epithelial-mesenchymal transition (EMT) in cystine-independent breast cancer cells conferred the cystine-addiction phenotype by modulating the signaling components of cystine addiction. Together, our data reveal that cystine-addiction is associated with EMT in breast cancer during tumor progression. These findings provide the genetic and mechanistic basis to explain how cystine deprivation triggers necrosis by activating pre-existing oncogenic pathways in cystine-addicted TNBC with prominent mesenchymal features.

Authors
Tang, X; Ding, C-K; Wu, J; Sjol, J; Wardell, S; Spasojevic, I; George, D; McDonnell, DP; Hsu, DS; Chang, JT; Chi, J-T
MLA Citation
Tang, X, Ding, C-K, Wu, J, Sjol, J, Wardell, S, Spasojevic, I, George, D, McDonnell, DP, Hsu, DS, Chang, JT, and Chi, J-T. "Cystine addiction of triple-negative breast cancer associated with EMT augmented death signaling." Oncogene 36.30 (July 2017): 4235-4242.
PMID
27869167
Source
epmc
Published In
Oncogene: Including Oncogene Reviews
Volume
36
Issue
30
Publish Date
2017
Start Page
4235
End Page
4242
DOI
10.1038/onc.2016.394

Inhibition of the Continuum of Radiation-Induced Normal Tissue Injury by a Redox-Active Mn Porphyrin.

Normal tissue damage after head and neck radiotherapy involves a continuum of pathologic events to the mucosa, tongue and salivary glands. We examined the radioprotective effects of MnBuOE, a redox-active manganese porphyrin, at three stages of normal tissue damage: immediate (leukocyte endothelial cell [L/E] interactions), early (mucositis) and late (xerostomia and fibrosis) after treatment. In this study, mice received 0 or 9 Gy irradiation to the oral cavity and salivary glands ± MnBuOE treatment. Changes in leukocyte-endothelial cell interactions were measured 24 h postirradiation. At 11 days postirradiation, mucositis was assessed with a cathepsin-sensitive near-infrared optical probe. Stimulated saliva production was quantified at 11 weeks postirradiation. Finally, histological analyses were conducted to assess the extent of long-term effects in salivary glands at 12 weeks postirradiation. MnBuOE reduced oral mucositis, xerostomia and salivary gland fibrosis after irradiation. Additionally, although we have previously shown that MnBuOE does not interfere with tumor control at high doses when administered with radiation alone, most head and neck cancer patients will be treated with the combinations of radiotherapy and cisplatin. Therefore, we also evaluated whether MnBuOE would protect tumors against radiation and cisplatin using tumor growth delay as an endpoint. Using a range of radiation doses, we saw no evidence that MnBuOE protected tumors from radiation and cisplatin. We conclude that MnBuOE radioprotects normal tissue at both early and late time points, without compromising anti-tumor effects of radiation and cisplatin.

Authors
Birer, SR; Lee, C-T; Choudhury, KR; Young, KH; Spasojevic, I; Batinic-Haberle, I; Crapo, JD; Dewhirst, MW; Ashcraft, KA
MLA Citation
Birer, SR, Lee, C-T, Choudhury, KR, Young, KH, Spasojevic, I, Batinic-Haberle, I, Crapo, JD, Dewhirst, MW, and Ashcraft, KA. "Inhibition of the Continuum of Radiation-Induced Normal Tissue Injury by a Redox-Active Mn Porphyrin." Radiation research 188.1 (July 2017): 94-104.
PMID
28517962
Source
epmc
Published In
Radiation Research
Volume
188
Issue
1
Publish Date
2017
Start Page
94
End Page
104
DOI
10.1667/rr14757.1.s1

A phase I study of single-agent perifosine for recurrent or refractory pediatric CNS and solid tumors

Authors
Becher, OJ; Millard, NE; Modak, S; Kushner, BH; Haque, S; Spasojevic, I; Trippett, TM; Gilheeney, SW; Khakoo, Y; Lyden, DC; De Braganca, KC; Kolesar, JM; Huse, JT; Kramer, K; Cheung, N-KV; Dunkel, IJ
MLA Citation
Becher, OJ, Millard, NE, Modak, S, Kushner, BH, Haque, S, Spasojevic, I, Trippett, TM, Gilheeney, SW, Khakoo, Y, Lyden, DC, De Braganca, KC, Kolesar, JM, Huse, JT, Kramer, K, Cheung, N-KV, and Dunkel, IJ. "A phase I study of single-agent perifosine for recurrent or refractory pediatric CNS and solid tumors." June 5, 2017.
Source
crossref
Published In
PloS one
Volume
12
Issue
6
Publish Date
2017
Start Page
e0178593
End Page
e0178593
DOI
10.1371/journal.pone.0178593

Urinary F2-isoprostanes and the risk of hypertension.

There is strong biological plausibility for a causal role of reactive oxygen species in vascular pathology but no direct epidemiological evidence linking elevated reactive oxygen species levels to hypertension development. We examined cross-sectional and prospective associations between oxidative status (urinary F2-isoprostanes) and hypertension in the Insulin Resistance Atherosclerosis Study cohort (n = 831).The cohort included non-Hispanic white, Hispanic, and non-Hispanic black individuals, with 252 (30%) having prevalent hypertension and 579 participants normotensive at baseline, 122 (21%) of whom developed hypertension during the 5-year follow-up. Four urinary F2-isoprostane isomers were quantified in baseline specimens using LC/MS-MS and were summarized as a composite index. Examined outcomes included hypertension status (yes/no), systolic (SBP) and diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP).Prevalent and incident hypertension were associated with greater age, Black race, impaired glucose tolerance, and greater BMI. F2-IsoP levels were lower among men and among non-Hispanic Blacks, were inversely associated with age, and were directly associated with BMI. No cross-sectional association was found between F2-isoprostanes and hypertension status (OR = 0.93, 0.77-0.12). Among the continuous measures of blood pressure only PP was associated with F2-isoprostanes at baseline (beta-coefficient = 0.99, 0.11-1.86). No prospective association was found between F2-isoprostanes and incident hypertension: OR = 0.98, 0.77-1.25. No prospective associations were found for systolic blood pressure and diastolic blood pressure, and pulse pressure. Mean arterial pressure showed an inverse association (beta-coefficient = -0.16, -0.31 to -0.01).Elevated F2-isoprostane levels do not increase the risk of hypertension.

Authors
Melton, CD; Luo, R; Wong, BJ; Spasojevic, I; Wagenknecht, LE; D'Agostino, RB; Il'yasova, D
MLA Citation
Melton, CD, Luo, R, Wong, BJ, Spasojevic, I, Wagenknecht, LE, D'Agostino, RB, and Il'yasova, D. "Urinary F2-isoprostanes and the risk of hypertension." Annals of epidemiology 27.6 (June 2017): 391-396.
PMID
28558917
Source
epmc
Published In
Annals of Epidemiology
Volume
27
Issue
6
Publish Date
2017
Start Page
391
End Page
396
DOI
10.1016/j.annepidem.2017.05.005

Mutant IDH1 Disrupts the Mouse Subventricular Zone and Alters Brain Tumor Progression.

IDH1 mutations occur in the majority of low-grade gliomas and lead to the production of the oncometabolite, D-2-hydroxyglutarate (D-2HG). To understand the effects of tumor-associated mutant IDH1 (IDH1-R132H) on both the neural stem cell (NSC) population and brain tumorigenesis, genetically faithful cell lines and mouse model systems were generated. Here, it is reported that mouse NSCs expressing Idh1-R132H displayed reduced proliferation due to p53-mediated cell-cycle arrest as well as a decreased ability to undergo neuronal differentiation. In vivo, Idh1-R132H expression reduced proliferation of cells within the germinal zone of the subventricular zone (SVZ). The NSCs within this area were dispersed and disorganized in mutant animals, suggesting that Idh1-R132H perturbed the NSCs and the microenvironment from which gliomas arise. In addition, tumor-bearing animals expressing mutant Idh1 displayed a prolonged survival and also overexpressed Olig2, features consistent with IDH1-mutated human gliomas. These data indicate that mutant Idh1 disrupts the NSC microenvironment and the candidate cell-of-origin for glioma; thus, altering the progression of tumorigenesis. In addition, this study provides a mutant Idh1 brain tumor model that genetically recapitulates human disease, laying the foundation for future investigations on mutant IDH1-mediated brain tumorigenesis and targeted therapy.Implications: Through the use of a conditional mutant mouse model that confers a less aggressive tumor phenotype, this study reveals that mutant Idh1 impacts the candidate cell-of-origin for gliomas. Mol Cancer Res; 15(5); 507-20. ©2017 AACR.

Authors
Pirozzi, CJ; Carpenter, AB; Waitkus, MS; Wang, CY; Zhu, H; Hansen, LJ; Chen, LH; Greer, PK; Feng, J; Wang, Y; Bock, CB; Fan, P; Spasojevic, I; McLendon, RE; Bigner, DD; He, Y; Yan, H
MLA Citation
Pirozzi, CJ, Carpenter, AB, Waitkus, MS, Wang, CY, Zhu, H, Hansen, LJ, Chen, LH, Greer, PK, Feng, J, Wang, Y, Bock, CB, Fan, P, Spasojevic, I, McLendon, RE, Bigner, DD, He, Y, and Yan, H. "Mutant IDH1 Disrupts the Mouse Subventricular Zone and Alters Brain Tumor Progression." Molecular cancer research : MCR 15.5 (May 2017): 507-520.
PMID
28148827
Source
epmc
Published In
Molecular cancer research : MCR
Volume
15
Issue
5
Publish Date
2017
Start Page
507
End Page
520
DOI
10.1158/1541-7786.mcr-16-0485

Challenges encountered during development of Mn porphyrin-based, potent redox-active drug and superoxide dismutase mimic, MnTnBuOE-2-PyP5+, and its alkoxyalkyl analogues.

We disclose here the studies that preceded and guided the preparation of the metal-based, redox-active therapeutic Mn(III) meso-tetrakis(N-n-butoxyethylpyridyl)porphyrin, MnTnBuOE-2-PyP5+ (BMX-001), which is currently in Phase I/II Clinical Trials at Duke University (USA) as a radioprotector of normal tissues in cancer patients. N-substituted pyridylporphyrins are ligands for Mn(III) complexes that are among the most potent superoxide dismutase mimics thus far synthesized. To advance their design, thereby improving their physical and chemical properties and bioavailability/toxicity profiles, we undertook a systematic study on placing oxygen atoms into N-alkylpyridyl chains via alkoxyalkylation reaction. For the first time we show here the unforeseen structural rearrangement that happens during the alkoxyalkylation reaction by the corresponding tosylates. Comprehensive experimental and computational approaches were employed to solve the rearrangement mechanism involved in quaternization of pyridyl nitrogens, which, instead of a single product, led to a variety of mixed N-alkoxyalkylated and N-alkylated pyridylporphyrins. The rearrangement mechanism involves the formation of an intermediate alkyl oxonium cation in a chain-length-dependent manner, which subsequently drives differential kinetics and thermodynamics of competing N-alkoxyalkylation versus in situ N-alkylation. The use of alkoxyalkyl tosylates, of different length of alkyl fragments adjacent to oxygen atom, allowed us to identify the set of alkyl fragments that would result in the synthesis of a single compound of high purity and excellent therapeutic potential.

Authors
Rajic, Z; Tovmasyan, A; de Santana, OL; Peixoto, IN; Spasojevic, I; do Monte, SA; Ventura, E; Rebouças, JS; Batinic-Haberle, I
MLA Citation
Rajic, Z, Tovmasyan, A, de Santana, OL, Peixoto, IN, Spasojevic, I, do Monte, SA, Ventura, E, Rebouças, JS, and Batinic-Haberle, I. "Challenges encountered during development of Mn porphyrin-based, potent redox-active drug and superoxide dismutase mimic, MnTnBuOE-2-PyP5+, and its alkoxyalkyl analogues." Journal of inorganic biochemistry 169 (April 2017): 50-60.
PMID
28131001
Source
epmc
Published In
Journal of Inorganic Biochemistry
Volume
169
Publish Date
2017
Start Page
50
End Page
60
DOI
10.1016/j.jinorgbio.2017.01.003

Wedelolactone Acts as Proteasome Inhibitor in Breast Cancer Cells.

Wedelolactone is a multi-target natural plant coumestan exhibiting cytotoxicity towards cancer cells. Although several molecular targets of wedelolactone have been recognized, the molecular mechanism of its cytotoxicity has not yet been elucidated. In this study, we show that wedelolactone acts as an inhibitor of chymotrypsin-like, trypsin-like, and caspase-like activities of proteasome in breast cancer cells. The proteasome inhibitory effect of wedelolactone was documented by (i) reduced cleavage of fluorogenic proteasome substrates; (ii) accumulation of polyubiquitinated proteins and proteins with rapid turnover in tumor cells; and (iii) molecular docking of wedelolactone into the active sites of proteasome catalytic subunits. Inhibition of proteasome by wedelolactone was independent on its ability to induce reactive oxygen species production by redox cycling with copper ions, suggesting that wedelolactone acts as copper-independent proteasome inhibitor. We conclude that the cytotoxicity of wedelolactone to breast cancer cells is partially mediated by targeting proteasomal protein degradation pathway. Understanding the structural basis for inhibitory mode of wedelolactone might help to open up new avenues for design of novel compounds efficiently inhibiting cancer cells.

Authors
Nehybová, T; Šmarda, J; Daniel, L; Stiborek, M; Kanický, V; Spasojevič, I; Preisler, J; Damborský, J; Beneš, P
MLA Citation
Nehybová, T, Šmarda, J, Daniel, L, Stiborek, M, Kanický, V, Spasojevič, I, Preisler, J, Damborský, J, and Beneš, P. "Wedelolactone Acts as Proteasome Inhibitor in Breast Cancer Cells." International journal of molecular sciences 18.4 (March 29, 2017).
PMID
28353647
Source
epmc
Published In
International journal of molecular sciences
Volume
18
Issue
4
Publish Date
2017
DOI
10.3390/ijms18040729

Metal maps of sclerotic hippocampi of patients with mesial temporal lobe epilepsy

Authors
Opačić, M; Ristić, AJ; Savić, D; Šelih, VS; Živin, M; Sokić, D; Raičević, S; Baščarević, V; Spasojević, I
MLA Citation
Opačić, M, Ristić, AJ, Savić, D, Šelih, VS, Živin, M, Sokić, D, Raičević, S, Baščarević, V, and Spasojević, I. "Metal maps of sclerotic hippocampi of patients with mesial temporal lobe epilepsy." Metallomics 9.2 (2017): 141-148.
Source
crossref
Published In
Metallomics
Volume
9
Issue
2
Publish Date
2017
Start Page
141
End Page
148
DOI
10.1039/C6MT00293E

Inhibiting androgen receptor nuclear entry in castration-resistant prostate cancer.

Clinical resistance to the second-generation antiandrogen enzalutamide in castration-resistant prostate cancer (CRPC), despite persistent androgen receptor (AR) activity in tumors, highlights an unmet medical need for next-generation antagonists. We have identified and characterized tetra-aryl cyclobutanes (CBs) as a new class of competitive AR antagonists that exhibit a unique mechanism of action. These CBs are structurally distinct from current antiandrogens (hydroxyflutamide, bicalutamide, and enzalutamide) and inhibit AR-mediated gene expression, cell proliferation, and tumor growth in several models of CRPC. Conformational profiling revealed that CBs stabilize an AR conformation resembling an unliganded receptor. Using a variety of techniques, it was determined that the AR-CB complex was not recruited to AR-regulated promoters and, like apo AR, remains sequestered in the cytoplasm, bound to heat shock proteins. Thus, we have identified third-generation AR antagonists whose unique mechanism of action suggests that they may have therapeutic potential in CRPC.

Authors
Pollock, JA; Wardell, SE; Parent, AA; Stagg, DB; Ellison, SJ; Alley, HM; Chao, CA; Lawrence, SA; Stice, JP; Spasojevic, I; Baker, JG; Kim, SH; McDonnell, DP; Katzenellenbogen, JA; Norris, JD
MLA Citation
Pollock, JA, Wardell, SE, Parent, AA, Stagg, DB, Ellison, SJ, Alley, HM, Chao, CA, Lawrence, SA, Stice, JP, Spasojevic, I, Baker, JG, Kim, SH, McDonnell, DP, Katzenellenbogen, JA, and Norris, JD. "Inhibiting androgen receptor nuclear entry in castration-resistant prostate cancer." Nature chemical biology 12.10 (October 2016): 795-801.
PMID
27501397
Source
epmc
Published In
Nature Chemical Biology
Volume
12
Issue
10
Publish Date
2016
Start Page
795
End Page
801
DOI
10.1038/nchembio.2131

Hypo-CpG methylation controls PTEN expression and cell apoptosis in irradiated lung.

The current study was designed to address our hypothesis that oxidative stress secondary to the ionizing event upregulates phosphatase and tensin homolog (PTEN) mRNA and protein in the lungs of C57BL/6J mice through oxidative DNA damage resulting in CpG hypomethylation in the PTEN promoter.Fibrosis-prone C57BL/6J mice were exposed to 0 or 15 Gy of 320 kVp X-rays to the whole thorax. Lung tissue was serially harvested at time points between one day and six months postirradiation. Tissue levels of PTEN mRNA, total protein, and phosphorylated PTEN, as well as CpG methylation of the PTEN promoter, expression of DNA methyltransferases 1 (Dnmt1) and 3a (Dnmt3a), NADPH oxidase 4 (Nox4) protein expression, and DNA damage levels were measured. The induction of DNA damage and global methylation changes were also examined in hydrogen peroxide (H2O2)-treated human umbilical vein endothelial cells (HUVECs) and human bronchial epithelial cells in vitro.These experiments demonstrate that PTEN mRNA and protein, Nox4 protein, and DNA damage levels increase continuously from one day to six months following radiation exposure. Elevated PTEN transcription and translation are likely the result of the observed decrease in CpG methylation of the PTEN promoter region. This finding is not consistent with the observed increase in Dnmt1 and Dnmt3a protein expression, implicating an alternative mechanism as the driving force behind hypomethylation. In vitro results provide evidence that H2O2 can induce DNA damage and affect DNA methylation status. The Mn porphyrin-based superoxide dismutase (SOD) mimic MnTnHEx-2-PyP(5+ )exhibited partial rescue from radiation-induced hypomethylation.Taken together, these data suggest that reactive oxygen species (ROS)-induced DNA damage results in hypomethylation of the PTEN promoter, upregulation of PTEN mRNA and protein, and a subsequent increase in apoptosis in irradiated lung tissue.

Authors
Zhang, X; Hadley, C; Jackson, IL; Zhang, Y; Zhang, A; Spasojevic, I; Haberle, IB; Vujaskovic, Z
MLA Citation
Zhang, X, Hadley, C, Jackson, IL, Zhang, Y, Zhang, A, Spasojevic, I, Haberle, IB, and Vujaskovic, Z. "Hypo-CpG methylation controls PTEN expression and cell apoptosis in irradiated lung." Free radical research 50.8 (August 2016): 875-886.
PMID
27367846
Source
epmc
Published In
Free Radical Research (Informa)
Volume
50
Issue
8
Publish Date
2016
Start Page
875
End Page
886
DOI
10.1080/10715762.2016.1189078

SSRI Augmentation by 5-Hydroxytryptophan Slow Release: Mouse Pharmacodynamic Proof of Concept.

Drugs, notably SSRIs, that elevate brain extracellular 5-HT (5-HTExt) are antidepressants. Unfortunately, most patients fail to remit. Multipronged clinical evidence suggests that elevating 5-HTExt beyond the SSRI effect enhances antidepressant efficacy, but previous such drug strategies had prohibitive limitations. In humans, adjunct treatment with the 5-HT precursor 5-hydroxytryptophan (5-HTP) elevates 5-HTExt beyond the SSRI effect. Small pilot trials suggest that adjunct 5-HTP can confer antidepressant response in treatment-resistant depression (TRD). However, sustained, stable 5-HTExt elevation is required for antidepressant effect; therefore, the rapid absorption and elimination of standard 5-HTP immediate release (IR) likely curtail 5-HTP IR's antidepressant potential. Slow-release (SR) drug delivery can crucially improve efficacy and safety of rapidly absorbed and eliminated compounds. Here we tested in mice the hypothesis that SR delivery will substantially improve 5-HTP's drug properties, by minimizing adverse effects and securing sustained 5-HTExt elevation beyond the SSRI effect. We modeled 5-HTP SR with minipumps, 5-HTP IR with injections, and chronic SSRI with dietary fluoxetine. We tested adjunct 5-HTP SR in wild-type mice and in mice with low brain 5-HT owing to expression of a mutant form of the brain 5-HT synthesis enzyme, tryptophan hydroxylase 2. In both lines of mice, adjunct 5-HTP SR synergized with SSRI to elevate 5-HTExt beyond the SSRI effect. We observed no adverse effect. Adjunct 5-HTP IR could not produce this therapy-like profile, producing transient 5-HTExt spikes and marked adverse effects. Integrated with a body of clinical data, our mouse data suggest that an adjunct 5-HTP SR drug could safely and effectively elevate 5-HTExt beyond the SSRI effect and represent a novel treatment for TRD.

Authors
Jacobsen, JP; Rudder, ML; Roberts, W; Royer, EL; Robinson, TJ; Oh, A; Spasojevic, I; Sachs, BD; Caron, MG
MLA Citation
Jacobsen, JP, Rudder, ML, Roberts, W, Royer, EL, Robinson, TJ, Oh, A, Spasojevic, I, Sachs, BD, and Caron, MG. "SSRI Augmentation by 5-Hydroxytryptophan Slow Release: Mouse Pharmacodynamic Proof of Concept." Neuropsychopharmacology 41.9 (August 2016): 2324-2334.
PMID
26932820
Source
epmc
Published In
Neuropsychopharmacology (Nature)
Volume
41
Issue
9
Publish Date
2016
Start Page
2324
End Page
2334
DOI
10.1038/npp.2016.35

Nonclinical Safety and Toxicokinetics of MnTnBuOE-2-PyP5+ (BMX-001).

BMX-001, a manganese porphyrin that has anti-inflammatory, antioxidant, and antitumor properties, is being developed as a potential therapeutic for high-grade glioma (HGG) and head and neck (H&N) cancer. An IND has been opened for BMX-001 in the treatment of HGG (NCT02655601) and another is in preparation for H&N. The safety of BMX-001 has been evaluated in a battery of nonclinical Good Laboratory Practice (GLP)-compliant studies. Systemic toxicity has been evaluated using the intended cGMP product administered subcutaneously for periods of up to 5 weeks in both the mouse and the monkey and included toxicokinetic evaluations to characterize systemic exposure and tissue distribution and clearance of BMX-001. In additional GLP studies, BMX-001 was not irritating to the skin or eye and caused no changes in cardiac rate or rhythm or blood pressure. Mixed results for genotoxicity were seen with the weight of evidence indicating that BMX-001 poses no genotoxic risk in humans. In systemic mouse and monkey studies, loading/maintenance dose no observed adverse effect levels were 12/2 mg/kg/dose and 6/2 mg/kg/dose, respectively, with maintenance doses administered every 3 days after the initial loading dose. Systemic data were used to determine a Food and Drug Administration-approved safe starting dose for the initial clinical study in patients with HGG. BMX-001 was detected in analyzed tissues, including the brain, persisting well past the short plasma clearance period. The highest levels of BMX-001 were seen in the liver and kidneys, with amounts in these tissues returning to close to undetectable levels after a 2-week cessation of dosing.

Authors
Gad, SC; Sullivan, DW; Spasojevic, I; Mujer, CV; Spainhour, CB; Crapo, JD
MLA Citation
Gad, SC, Sullivan, DW, Spasojevic, I, Mujer, CV, Spainhour, CB, and Crapo, JD. "Nonclinical Safety and Toxicokinetics of MnTnBuOE-2-PyP5+ (BMX-001)." July 2016.
PMID
27098749
Source
epmc
Published In
International Journal of Toxicology (SAGE Publications)
Volume
35
Issue
4
Publish Date
2016
Start Page
438
End Page
453
DOI
10.1177/1091581816642766

Small molecule dual-inhibitors of TRPV4 and TRPA1 for attenuation of inflammation and pain.

TRPV4 ion channels represent osmo-mechano-TRP channels with pleiotropic function and wide-spread expression. One of the critical functions of TRPV4 in this spectrum is its involvement in pain and inflammation. However, few small-molecule inhibitors of TRPV4 are available. Here we developed TRPV4-inhibitory molecules based on modifications of a known TRPV4-selective tool-compound, GSK205. We not only increased TRPV4-inhibitory potency, but surprisingly also generated two compounds that potently co-inhibit TRPA1, known to function as chemical sensor of noxious and irritant signaling. We demonstrate TRPV4 inhibition by these compounds in primary cells with known TRPV4 expression - articular chondrocytes and astrocytes. Importantly, our novel compounds attenuate pain behavior in a trigeminal irritant pain model that is known to rely on TRPV4 and TRPA1. Furthermore, our novel dual-channel blocker inhibited inflammation and pain-associated behavior in a model of acute pancreatitis - known to also rely on TRPV4 and TRPA1. Our results illustrate proof of a novel concept inherent in our prototype compounds of a drug that targets two functionally-related TRP channels, and thus can be used to combat isoforms of pain and inflammation in-vivo that involve more than one TRP channel. This approach could provide a novel paradigm for treating other relevant health conditions.

Authors
Kanju, P; Chen, Y; Lee, W; Yeo, M; Lee, SH; Romac, J; Shahid, R; Fan, P; Gooden, DM; Simon, SA; Spasojevic, I; Mook, RA; Liddle, RA; Guilak, F; Liedtke, WB
MLA Citation
Kanju, P, Chen, Y, Lee, W, Yeo, M, Lee, SH, Romac, J, Shahid, R, Fan, P, Gooden, DM, Simon, SA, Spasojevic, I, Mook, RA, Liddle, RA, Guilak, F, and Liedtke, WB. "Small molecule dual-inhibitors of TRPV4 and TRPA1 for attenuation of inflammation and pain." Scientific reports 6 (June 2016): 26894-.
Website
http://hdl.handle.net/10161/12075
PMID
27247148
Source
epmc
Published In
Scientific Reports
Volume
6
Publish Date
2016
Start Page
26894
DOI
10.1038/srep26894

Neurobehavioral radiation mitigation to standard brain cancer therapy regimens by Mn(III) n-butoxyethylpyridylporphyrin-based redox modifier.

Combinations of radiotherapy (RT) and chemotherapy have shown efficacy toward brain tumors. However, therapy-induced oxidative stress can damage normal brain tissue, resulting in both progressive neurocognitive loss and diminished quality of life. We have recently shown that MnTnBuOE-2-PyP(5+) (Mn(III)meso-tetrakis(N-n-butoxyethylpyridinium -2-yl)porphyrin) rescued RT-induced white matter damage in cranially-irradiated mice. Radiotherapy is not used in isolation for treatment of brain tumors; temozolomide is the standard-of-care for adult glioblastoma, whereas cisplatin is often used for treatment of pediatric brain tumors. Therefore, we evaluated the brain radiation mitigation ability of MnTnBuOE-2-PyP(5+) after either temozolomide or cisplatin was used singly or in combination with 10 Gy RT. MnTnBuOE-2-PyP(5+) accumulated in brains at low nanomolar levels. Histological and neurobehavioral testing showed a drastic decrease (1) of axon density in the corpus callosum and (2) rotorod and running wheel performance in the RT only treatment group, respectively. MnTnBuOE-2-PyP(5+) completely rescued this phenotype in irradiated animals. In the temozolomide groups, temozolomide/ RT treatment resulted in further decreased rotorod responses over RT alone. Again, MnTnBuOE-2-PyP(5+) treatment rescued the negative effects of both temozolomide ± RT on rotorod performance. While the cisplatin-treated groups did not give similar results as the temozolomide groups, inclusion of MnTnBuOE-2-PyP(5+) did not negatively affect rotorod performance. Additionally, MnTnBuOE-2-PyP(5+) sensitized glioblastomas to either RT ± temozolomide in flank tumor models. Mice treated with both MnTnBuOE-2-PyP(5+) and radio-/chemo-therapy herein demonstrated brain radiation mitigation. MnTnBuOE-2-PyP(5+) may well serve as a normal tissue radio-/chemo-mitigator adjuvant therapy to standard brain cancer treatment regimens. Environ. Mol. Mutagen. 57:372-381, 2016. © 2016 Wiley Periodicals, Inc.

Authors
Weitzel, DH; Tovmasyan, A; Ashcraft, KA; Boico, A; Birer, SR; Roy Choudhury, K; Herndon, J; Rodriguiz, RM; Wetsel, WC; Peters, KB; Spasojevic, I; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Weitzel, DH, Tovmasyan, A, Ashcraft, KA, Boico, A, Birer, SR, Roy Choudhury, K, Herndon, J, Rodriguiz, RM, Wetsel, WC, Peters, KB, Spasojevic, I, Batinic-Haberle, I, and Dewhirst, MW. "Neurobehavioral radiation mitigation to standard brain cancer therapy regimens by Mn(III) n-butoxyethylpyridylporphyrin-based redox modifier." Environmental and molecular mutagenesis 57.5 (June 2016): 372-381.
PMID
27224425
Source
epmc
Published In
Environmental and Molecular Mutagenesis
Volume
57
Issue
5
Publish Date
2016
Start Page
372
End Page
381
DOI
10.1002/em.22021

Antioxidative Activity of Colostrum and Human Milk: Effects of Pasteurization and Storage.

Milk banks collect, pasteurize, and freeze/store human milk. The processing may alter redox properties of milk, but the effects have not been fully examined.We collected 10 mature milk and 10 colostrum samples and applied a battery of biochemical assays and electron paramagnetic resonance spectroscopy to inspect changes that milk undergoes with pasteurization and 30 days storage at -20°C.Pasteurization and storage of raw milk did not affect total nonenzymatic antioxidative capacity, but specific components and features were altered. Urate radical and ascorbyl radical emerge as products of exposure of milk to hydroxyl radical-generating system. Processing shifted the load of antioxidative activity from ascorbate to urate and lowered the capacity of milk to diminish hydroxyl radical. Pasteurization caused a significant drop in the activity of 2 major antioxidative enzymes-superoxide dismutase and glutathione peroxidase, whereas freezing/storage of raw milk affected only superoxide dismutase. Colostrum showed drastically higher total nonenzymatic antioxidative capacity, hydroxyl radical scavenging ability, and glutathione reductase activity compared with mature milk.Pasteurization and storage affect nonenzymatic and enzymatic antioxidative agents in human milk. It appears that nonenzymatic antioxidative systems in colostrum and milk are different. The effects of processing may be partially compensated by fortification/spiking with ascorbate before use.

Authors
Marinković, V; Ranković-Janevski, M; Spasić, S; Nikolić-Kokić, A; Lugonja, N; Djurović, D; Miletić, S; Vrvić, MM; Spasojević, I
MLA Citation
Marinković, V, Ranković-Janevski, M, Spasić, S, Nikolić-Kokić, A, Lugonja, N, Djurović, D, Miletić, S, Vrvić, MM, and Spasojević, I. "Antioxidative Activity of Colostrum and Human Milk: Effects of Pasteurization and Storage." Journal of pediatric gastroenterology and nutrition 62.6 (June 2016): 901-906.
PMID
26794491
Source
epmc
Published In
Journal of Pediatric Gastroenterology and Nutrition
Volume
62
Issue
6
Publish Date
2016
Start Page
901
End Page
906
DOI
10.1097/mpg.0000000000001090

What if cell culture media do not mimic in vivo redox settings?

Here, I address the topic of suitability for redox research of common settings in cell cultures. This is done through the prism of in vitro anticancer effects of vitamin C. Cell culture media show lower concentrations of iron and a higher level of oxygen compared to interstitial fluid. Such a setup promotes ascorbate-mediated production and accumulation of hydrogen peroxide, which efficiently kills a variety of cancer cell lines. However, the anticancer effects are annihilated if the iron level is corrected to mimic in vivo concentrations. It appears that the potential benefits of application of vitamin C in cancer treatment have been significantly overestimated. This might be true for other pro-oxidative agents as well, such as some (poly)phenols. We urgently need to establish medium formula and culture maintenance settings that are optimal for redox research.

Authors
Spasojević, I
MLA Citation
Spasojević, I. "What if cell culture media do not mimic in vivo redox settings?." Redox report : communications in free radical research 21.3 (May 2016): 127-129.
PMID
26221760
Source
epmc
Published In
Redox Report
Volume
21
Issue
3
Publish Date
2016
Start Page
127
End Page
129
DOI
10.1179/1351000215y.0000000036

Photo-redox reactions of indole and ferric iron in water

Authors
Milić Komić, S; Pristov, JB; Popović-Bijelić, A; Zakrzewska, J; Stanić, M; Kalauzi, A; Spasojević, I
MLA Citation
Milić Komić, S, Pristov, JB, Popović-Bijelić, A, Zakrzewska, J, Stanić, M, Kalauzi, A, and Spasojević, I. "Photo-redox reactions of indole and ferric iron in water." Applied Catalysis B: Environmental 185 (May 2016): 174-180.
Source
crossref
Published In
Applied Catalysis B: Environmental
Volume
185
Publish Date
2016
Start Page
174
End Page
180
DOI
10.1016/j.apcatb.2015.12.018

Opinion on Schmidt et al.

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "Opinion on Schmidt et al." Antioxidants & redox signaling 24.9 (March 2016): 518-524. (Letter)
PMID
26857355
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
24
Issue
9
Publish Date
2016
Start Page
518
End Page
524
DOI
10.1089/ars.2015.6623

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer.

Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

Authors
Whitley, MJ; Cardona, DM; Lazarides, AL; Spasojevic, I; Ferrer, JM; Cahill, J; Lee, C-L; Snuderl, M; Blazer, DG; Hwang, ES; Greenup, RA; Mosca, PJ; Mito, JK; Cuneo, KC; Larrier, NA; O'Reilly, EK; Riedel, RF; Eward, WC; Strasfeld, DB; Fukumura, D; Jain, RK; Lee, WD; Griffith, LG; Bawendi, MG; Kirsch, DG; Brigman, BE
MLA Citation
Whitley, MJ, Cardona, DM, Lazarides, AL, Spasojevic, I, Ferrer, JM, Cahill, J, Lee, C-L, Snuderl, M, Blazer, DG, Hwang, ES, Greenup, RA, Mosca, PJ, Mito, JK, Cuneo, KC, Larrier, NA, O'Reilly, EK, Riedel, RF, Eward, WC, Strasfeld, DB, Fukumura, D, Jain, RK, Lee, WD, Griffith, LG, Bawendi, MG, Kirsch, DG, and Brigman, BE. "A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer." Science translational medicine 8.320 (January 2016): 320ra4-.
PMID
26738797
Source
epmc
Published In
Science Translational Medicine
Volume
8
Issue
320
Publish Date
2016
Start Page
320ra4
DOI
10.1126/scitranslmed.aad0293

Mitochondria-Targeted Antioxidants: Future Perspectives in Kidney Ischemia Reperfusion Injury.

Kidney ischemia/reperfusion injury emerges in various clinical settings as a great problem complicating the course and outcome. Ischemia/reperfusion injury is still an unsolved puzzle with a great diversity of investigational approaches, putting the focus on oxidative stress and mitochondria. Mitochondria are both sources and targets of ROS. They participate in initiation and progression of kidney ischemia/reperfusion injury linking oxidative stress, inflammation, and cell death. The dependence of kidney proximal tubule cells on oxidative mitochondrial metabolism makes them particularly prone to harmful effects of mitochondrial damage. The administration of antioxidants has been used as a way to prevent and treat kidney ischemia/reperfusion injury for a long time. Recently a new method based on mitochondria-targeted antioxidants has become the focus of interest. Here we review the current status of results achieved in numerous studies investigating these novel compounds in ischemia/reperfusion injury which specifically target mitochondria such as MitoQ, Szeto-Schiller (SS) peptides (Bendavia), SkQ1 and SkQR1, and superoxide dismutase mimics. Based on the favorable results obtained in the studies that have examined myocardial ischemia/reperfusion injury, ongoing clinical trials investigate the efficacy of some novel therapeutics in preventing myocardial infarct. This also implies future strategies in preventing kidney ischemia/reperfusion injury.

Authors
Kezic, A; Spasojevic, I; Lezaic, V; Bajcetic, M
MLA Citation
Kezic, A, Spasojevic, I, Lezaic, V, and Bajcetic, M. "Mitochondria-Targeted Antioxidants: Future Perspectives in Kidney Ischemia Reperfusion Injury." Oxidative Medicine and Cellular Longevity 2016 (January 2016): 2950503-. (Review)
PMID
27313826
Source
epmc
Published In
Oxidative Medicine and Cellular Longevity
Volume
2016
Publish Date
2016
Start Page
2950503
DOI
10.1155/2016/2950503

Anticancer therapeutic potential of Mn porphyrin/ascorbate system.

Ascorbate (Asc) as a single agent suppressed growth of several tumor cell lines in a mouse model. It has been tested in a Phase I Clinical Trial on pancreatic cancer patients where it exhibited no toxicity to normal tissue yet was of only marginal efficacy. The mechanism of its anticancer effect was attributed to the production of tumoricidal hydrogen peroxide (H2O2) during ascorbate oxidation catalyzed by endogenous metalloproteins. The amount of H2O2 could be maximized with exogenous catalyst that has optimized properties for such function and is localized within tumor. Herein we studied 14 Mn porphyrins (MnPs) which differ vastly with regards to their redox properties, charge, size/bulkiness and lipophilicity. Such properties affect the in vitro and in vivo ability of MnPs (i) to catalyze ascorbate oxidation resulting in the production of H2O2; (ii) to subsequently employ H2O2 in the catalysis of signaling proteins oxidations affecting cellular survival pathways; and (iii) to accumulate at site(s) of interest. The metal-centered reduction potential of MnPs studied, E1/2 of Mn(III)P/Mn(II)P redox couple, ranged from -200 to +350 mV vs NHE. Anionic and cationic, hydrophilic and lipophilic as well as short- and long-chained and bulky compounds were explored. Their ability to catalyze ascorbate oxidation, and in turn cytotoxic H2O2 production, was explored via spectrophotometric and electrochemical means. Bell-shape structure-activity relationship (SAR) was found between the initial rate for the catalysis of ascorbate oxidation, vo(Asc)ox and E1/2, identifying cationic Mn(III) N-substituted pyridylporphyrins with E1/2>0 mV vs NHE as efficient catalysts for ascorbate oxidation. The anticancer potential of MnPs/Asc system was subsequently tested in cellular (human MCF-7, MDA-MB-231 and mouse 4T1) and animal models of breast cancer. At the concentrations where ascorbate (1mM) and MnPs (1 or 5 µM) alone did not trigger any alteration in cell viability, combined treatment suppressed cell viability up to 95%. No toxicity was observed with normal human breast epithelial HBL-100 cells. Bell-shape relationship, essentially identical to vo(Asc)oxvs E1/2, was also demonstrated between MnP/Asc-controlled cytotoxicity and E1/2-controlled vo(Asc)ox. Magnetic resonance imaging studies were conducted to explore the impact of ascorbate on T1-relaxivity. The impact of MnP/Asc on intracellular thiols and on GSH/GSSG and Cys/CySS ratios in 4T1 cells was assessed and cellular reduction potentials were calculated. The data indicate a significant increase in cellular oxidative stress induced by MnP/Asc. Based on vo(Asc)oxvs E1/2 relationships and cellular toxicity, MnTE-2-PyP(5+) was identified as the best catalyst among MnPs studied. Asc and MnTE-2-PyP(5+) were thus tested in a 4T1 mammary mouse flank tumor model. The combination of ascorbate (4 g/kg) and MnTE-2-PyP(5+) (0.2mg/kg) showed significant suppression of tumor growth relative to either MnTE-2-PyP(5+) or ascorbate alone. About 7-fold higher accumulation of MnTE-2-PyP(5+) in tumor vs normal tissue was found to contribute largely to the anticancer effect.

Authors
Tovmasyan, A; Sampaio, RS; Boss, M-K; Bueno-Janice, JC; Bader, BH; Thomas, M; Reboucas, JS; Orr, M; Chandler, JD; Go, Y-M; Jones, DP; Venkatraman, TN; Haberle, S; Kyui, N; Lascola, CD; Dewhirst, MW; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Sampaio, RS, Boss, M-K, Bueno-Janice, JC, Bader, BH, Thomas, M, Reboucas, JS, Orr, M, Chandler, JD, Go, Y-M, Jones, DP, Venkatraman, TN, Haberle, S, Kyui, N, Lascola, CD, Dewhirst, MW, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Anticancer therapeutic potential of Mn porphyrin/ascorbate system." Free radical biology & medicine 89 (December 2015): 1231-1247.
PMID
26496207
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
89
Publish Date
2015
Start Page
1231
End Page
1247
DOI
10.1016/j.freeradbiomed.2015.10.416

Corrigendum to ‘An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins – From superoxide dismutation to H2O2-driven pathways’ [Redox Biology 5C (2015) 43–65]

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "Corrigendum to ‘An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins – From superoxide dismutation to H2O2-driven pathways’ [Redox Biology 5C (2015) 43–65]." Redox Biology 6 (December 2015): 656-656.
Source
crossref
Published In
Redox Biology
Volume
6
Publish Date
2015
Start Page
656
End Page
656
DOI
10.1016/j.redox.2015.09.001

Reactions of superoxide dismutases with HS(-)/H2S and superoxide radical anion: An in vitro EPR study.

Interactions of hydrogen sulfide (HS(-)/H2S), a reducing signaling species, with superoxide dimutases (SOD) are poorly understood. We applied low-T EPR spectroscopy to examine the effects of HS(-)/H2S and superoxide radical anion O2.- on metallocenters of FeSOD, MnSOD, and CuZnSOD. HS(-)/H2S did not affect FeSOD, whereas active centers of MnSOD and CuZnSOD were open to this agent. Cu(2+) was reduced to Cu(1+), while manganese appears to be released from MnSOD active center. Untreated and O2.- treated FeSOD and MnSOD predominantly show 5 d-electron systems, i.e. Fe(3+) and Mn(2+). Our study provides new details on the mechanisms of (patho)physiological effects of HS(-)/H2S.

Authors
Bolić, B; Mijušković, A; Popović-Bijelić, A; Nikolić-Kokić, A; Spasić, S; Blagojević, D; Spasić, MB; Spasojević, I
MLA Citation
Bolić, B, Mijušković, A, Popović-Bijelić, A, Nikolić-Kokić, A, Spasić, S, Blagojević, D, Spasić, MB, and Spasojević, I. "Reactions of superoxide dismutases with HS(-)/H2S and superoxide radical anion: An in vitro EPR study." Nitric oxide : biology and chemistry 51 (December 2015): 19-23.
PMID
26436856
Source
epmc
Published In
Nitric Oxide: Biology and Chemistry
Volume
51
Publish Date
2015
Start Page
19
End Page
23
DOI
10.1016/j.niox.2015.09.008

Novel Manganese-Porphyrin Superoxide Dismutase-Mimetic Widens the Therapeutic Margin in a Preclinical Head and Neck Cancer Model.

To test the effects of a novel Mn porphyrin oxidative stress modifier, Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin (MnBuOE), for its radioprotective and radiosensitizing properties in normal tissue versus tumor, respectively.Murine oral mucosa and salivary glands were treated with a range of radiation doses with or without MnBuOE to establish the dose-effect curves for mucositis and xerostomia. Radiation injury was quantified by intravital near-infrared imaging of cathepsin activity, assessment of salivation, and histologic analysis. To evaluate effects of MnBuOE on the tumor radiation response, we administered the drug as an adjuvant to fractionated radiation of FaDu xenografts. Again, a range of radiation therapy (RT) doses was administered to establish the radiation dose-effect curve. The 50% tumor control dose values with or without MnBuOE and dose-modifying factor were determined.MnBuOE protected normal tissue by reducing RT-mediated mucositis, xerostomia, and fibrosis. The dose-modifying factor for protection against xerostomia was 0.77. In contrast, MnBuOE increased tumor local control rates compared with controls. The dose-modifying factor, based on the ratio of 50% tumor control dose values, was 1.3. Immunohistochemistry showed that MnBuOE-treated tumors exhibited a significant influx of M1 tumor-associated macrophages, which provides mechanistic insight into its radiosensitizing effects in tumors.MnBuOE widens the therapeutic margin by decreasing the dose of radiation required to control tumor, while increasing normal tissue resistance to RT-mediated injury. This is the first study to quantitatively demonstrate the magnitude of a single drug's ability to radioprotect normal tissue while radiosensitizing tumor.

Authors
Ashcraft, KA; Boss, M-K; Tovmasyan, A; Roy Choudhury, K; Fontanella, AN; Young, KH; Palmer, GM; Birer, SR; Landon, CD; Park, W; Das, SK; Weitner, T; Sheng, H; Warner, DS; Brizel, DM; Spasojevic, I; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Ashcraft, KA, Boss, M-K, Tovmasyan, A, Roy Choudhury, K, Fontanella, AN, Young, KH, Palmer, GM, Birer, SR, Landon, CD, Park, W, Das, SK, Weitner, T, Sheng, H, Warner, DS, Brizel, DM, Spasojevic, I, Batinic-Haberle, I, and Dewhirst, MW. "Novel Manganese-Porphyrin Superoxide Dismutase-Mimetic Widens the Therapeutic Margin in a Preclinical Head and Neck Cancer Model." International journal of radiation oncology, biology, physics 93.4 (November 2015): 892-900.
PMID
26530759
Source
epmc
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
93
Issue
4
Publish Date
2015
Start Page
892
End Page
900
DOI
10.1016/j.ijrobp.2015.07.2283

A comprehensive evaluation of catalase-like activity of different classes of redox-active therapeutics.

Because of the increased insight into the biological role of hydrogen peroxide (H2O2) under physiological and pathological conditions and the role it presumably plays in the action of natural and synthetic redox-active drugs, there is a need to accurately define the type and magnitude of reactions that may occur with this intriguing and key species of redoxome. Historically, and frequently incorrectly, the impact of catalase-like activity has been assigned to play a major role in the action of many redox-active drugs, mostly SOD mimics and peroxynitrite scavengers, and in particular MnTBAP(3-) and Mn salen derivatives. The advantage of one redox-active compound over another has often been assigned to the differences in catalase-like activity. Our studies provide substantial evidence that Mn(III) N-alkylpyridylporphyrins couple with H2O2 in actions other than catalase-related. Herein we have assessed the catalase-like activities of different classes of compounds: Mn porphyrins (MnPs), Fe porphyrins (FePs), Mn(III) salen (EUK-8), and Mn(II) cyclic polyamines (SOD-active M40403 and SOD-inactive M40404). Nitroxide (tempol), nitrone (NXY-059), ebselen, and MnCl2, which have not been reported as catalase mimics, were used as negative controls, while catalase enzyme was a positive control. The dismutation of H2O2 to O2 and H2O was followed via measuring oxygen evolved with a Clark oxygen electrode at 25°C. The catalase enzyme was found to have kcat(H2O2)=1.5×10(6)M(-1) s(-1). The yield of dismutation, i.e., the maximal amount of O2 evolved, was assessed also. The magnitude of the yield reflects an interplay between the kcat(H2O2) and the stability of compounds toward H2O2-driven oxidative degradation, and is thus an accurate measure of the efficacy of a catalyst. The kcat(H2O2) values for 12 cationic Mn(III) N-substituted (alkyl and alkoxyalkyl) pyridylporphyrin-based SOD mimics and Mn(III) N,N'-dialkylimidazolium porphyrin, MnTDE-2-ImP(5+), ranged from 23 to 88M(-1) s(-1). The analogous Fe(III) N-alkylpyridylporphyrins showed ~10-fold higher activity than the corresponding MnPs, but the values of kcat(H2O2) are still ~4 orders of magnitude lower than that of the enzyme. While the kcat(H2O2) values for Fe ethyl and n-octyl analogs were 803.5 and 368.4M(-1) s(-1), respectively, the FePs are more prone to H2O2-driven oxidative degradation, therefore allowing for similar yields in H2O2 dismutation as analogous MnPs. The kcat(H2O2) values are dependent on the electron deficiency of the metal site as it controls the peroxide binding in the first step of the dismutation process. SOD-like activities depend on electron deficiency of the metal site also, as it controls the first step of O2(●-) dismutation. In turn, the kcat(O2(●-)) parallels the kcat(H2O2). Therefore, the electron-rich anionic non-SOD mimic MnTBAP(3-) has essentially very low catalase-like activity, kcat(H2O2)=5.8M(-1) s(-1). The catalase-like activities of Mn(III) and Fe(III) porphyrins are at most, 0.0004 and 0.05% of the enzyme activity, respectively. The kcat(H2O2) values of 8.2 and 6.5M(-1) s(-1) were determined for electron-rich Mn(II) cyclic polyamine-based compounds, M40403 and M40404, respectively. The EUK-8, with modest SOD-like activity, has only slightly higher kcat(H2O2)=13.5M(-1) s(-1). The biological relevance of kcat(H2O2) of MnTE-2-PyP(5+), MnTDE-2-ImP(5+), MnTBAP(3-), FeTE-2-PyP(5+), M40403, M40404, and Mn salen was evaluated in wild-type and peroxidase/catalase-deficient E. coli.

Authors
Tovmasyan, A; Maia, CGC; Weitner, T; Carballal, S; Sampaio, RS; Lieb, D; Ghazaryan, R; Ivanovic-Burmazovic, I; Ferrer-Sueta, G; Radi, R; Reboucas, JS; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Maia, CGC, Weitner, T, Carballal, S, Sampaio, RS, Lieb, D, Ghazaryan, R, Ivanovic-Burmazovic, I, Ferrer-Sueta, G, Radi, R, Reboucas, JS, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "A comprehensive evaluation of catalase-like activity of different classes of redox-active therapeutics." Free radical biology & medicine 86 (September 2015): 308-321.
PMID
26026699
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
86
Publish Date
2015
Start Page
308
End Page
321
DOI
10.1016/j.freeradbiomed.2015.05.018

Structure-activity studies of Wnt/β-catenin inhibition in the Niclosamide chemotype: Identification of derivatives with improved drug exposure.

The Wnt signaling pathway plays a key role in regulation of organ development and tissue homeostasis. Dysregulated Wnt activity is one of the major underlying mechanisms responsible for many diseases including cancer. We previously reported the FDA-approved anthelmintic drug Niclosamide inhibits Wnt/β-catenin signaling and suppresses colon cancer cell growth in vitro and in vivo. Niclosamide is a multi-functional drug that possesses important biological activity in addition to inhibition of Wnt/β-catenin signaling. Here, we studied the SAR of Wnt signaling inhibition in the anilide and salicylamide region of Niclosamide. We found that the 4'-nitro substituent can be effectively replaced by trifluoromethyl or chlorine and that the potency of inhibition was dependent on the substitution pattern in the anilide ring. Non-anilide, N-methyl amides and reverse amide derivatives lost significant potency, while acylated salicylamide derivatives inhibited signaling with potency similar to non-acyl derivatives. Niclosamide's low systemic exposure when dosed orally may hinder its use to treat systemic disease. To overcome this limitation we identified an acyl derivative of Niclosamide, DK-520 (compound 32), that significantly increased both the plasma concentration and the duration of exposure of Niclosamide when dosed orally. The studies herein provide a medicinal chemical foundation to improve the pharmacokinetic exposure of Niclosamide and Wnt-signaling inhibitors based on the Niclosamide chemotype. The identification of novel derivatives of Niclosamide that metabolize to Niclosamide and increase its drug exposure may provide important research tools for in vivo studies and provide drug candidates for treating cancers with dysregulated Wnt signaling including drug-resistant cancers. Moreover, since Niclosamide is a multi-functional drug, new research tools such as DK520 could directly result in novel treatments against bacterial and viral infection, lupus, and metabolic diseases such as type II diabetes, NASH and NAFLD.

Authors
Mook, RA; Wang, J; Ren, X-R; Chen, M; Spasojevic, I; Barak, LS; Lyerly, HK; Chen, W
MLA Citation
Mook, RA, Wang, J, Ren, X-R, Chen, M, Spasojevic, I, Barak, LS, Lyerly, HK, and Chen, W. "Structure-activity studies of Wnt/β-catenin inhibition in the Niclosamide chemotype: Identification of derivatives with improved drug exposure." Bioorganic & medicinal chemistry 23.17 (September 2015): 5829-5838.
PMID
26272032
Source
epmc
Published In
Bioorganic & Medicinal Chemistry
Volume
23
Issue
17
Publish Date
2015
Start Page
5829
End Page
5838
DOI
10.1016/j.bmc.2015.07.001

A paclitaxel-loaded recombinant polypeptide nanoparticle outperforms Abraxane in multiple murine cancer models.

Packaging clinically relevant hydrophobic drugs into a self-assembled nanoparticle can improve their aqueous solubility, plasma half-life, tumour-specific uptake and therapeutic potential. To this end, here we conjugated paclitaxel (PTX) to recombinant chimeric polypeptides (CPs) that spontaneously self-assemble into ∼60 nm near-monodisperse nanoparticles that increased the systemic exposure of PTX by sevenfold compared with free drug and twofold compared with the Food and Drug Administration-approved taxane nanoformulation (Abraxane). The tumour uptake of the CP-PTX nanoparticle was fivefold greater than free drug and twofold greater than Abraxane. In a murine cancer model of human triple-negative breast cancer and prostate cancer, CP-PTX induced near-complete tumour regression after a single dose in both tumour models, whereas at the same dose, no mice treated with Abraxane survived for >80 days (breast) and 60 days (prostate), respectively. These results show that a molecularly engineered nanoparticle with precisely engineered design features outperforms Abraxane, the current gold standard for PTX delivery.

Authors
Bhattacharyya, J; Bellucci, JJ; Weitzhandler, I; McDaniel, JR; Spasojevic, I; Li, X; Lin, C-C; Chi, J-TA; Chilkoti, A
MLA Citation
Bhattacharyya, J, Bellucci, JJ, Weitzhandler, I, McDaniel, JR, Spasojevic, I, Li, X, Lin, C-C, Chi, J-TA, and Chilkoti, A. "A paclitaxel-loaded recombinant polypeptide nanoparticle outperforms Abraxane in multiple murine cancer models." Nature communications 6 (August 4, 2015): 7939-.
PMID
26239362
Source
epmc
Published In
Nature Communications
Volume
6
Publish Date
2015
Start Page
7939
DOI
10.1038/ncomms8939

An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins--From superoxide dismutation to H2O2-driven pathways.

Most of the SOD mimics thus far developed belong to the classes of Mn-(MnPs) and Fe porphyrins(FePs), Mn(III) salens, Mn(II) cyclic polyamines and metal salts. Due to their remarkable stability we have predominantly explored Mn porphyrins, aiming initially at mimicking kinetics and thermodynamics of the catalysis of O2(-) dismutation by SOD enzymes. Several MnPs are of potency similar to SOD enzymes. The in vivo bioavailability and toxicity of MnPs have been addressed also. Numerous in vitro and in vivo studies indicate their impressive therapeutic efficacy. Increasing insight into complex cellular redox biology has been accompanied by increasing awareness of complex redox chemistry of MnPs. During O2(-) dismutation process, the most powerful Mn porphyrin-based SOD mimics reduce and oxidize O2(-) with close to identical rate constants. MnPs reduce and oxidize other reactive species also (none of them specific to MnPs), acting as reductants (antioxidant) and pro-oxidants. Distinction must be made between the type of reactions of MnPs and the favorable therapeutic effects we observe; the latter may be of either anti- or pro-oxidative nature. H2O2/MnP mediated oxidation of protein thiols and its impact on cellular transcription seems to dominate redox biology of MnPs. It has been thus far demonstrated that the ability of MnPs to catalyze O2(-) dismutation parallels all other reactivities (such as ONOO(-) reduction) and in turn their therapeutic efficacies. Assuming that all diseases have in common the perturbation of cellular redox environment, developing SOD mimics still seems to be the appropriate strategy for the design of potent redox-active therapeutics.

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins--From superoxide dismutation to H2O2-driven pathways." Redox biology 5 (August 2015): 43-65. (Review)
PMID
25827425
Source
epmc
Published In
Redox Biology
Volume
5
Publish Date
2015
Start Page
43
End Page
65
DOI
10.1016/j.redox.2015.01.017

A method for in-gel fluorescent visualization of proteins after native and sodium dodecyl sulfate polyacrylamide gel electrophoresis.

We have developed a simple one-step 30-min method for fluorescent visualization of proteins in native and sodium dodecyl sulfate polyacrylamide gel electrophoresis (PAGE) gels. The method is based on formation of strong fluorophores via potassium ferricyanide-provoked oxidation of tryptophan (Trp). Following PAGE, gels are soaked in water solution of potassium ferricyanide (100 mM) and NaOH (1 M) and are kept in the dark for 30 min. Gels are then transferred to water and scanned. The sensitivity of the method was slightly lower compared with standard Coomassie Brilliant Blue (CBB) staining. The method can be useful when rapid acquisition of data is of the essence. After preview, gels can be post-stained using the CBB protocol for further analysis. The intensity of fluorescence is dependent on Trp number, so the protocol might find application in the quantification of Trp residues as illustrated here. Importantly, there is room for improvement of the method. Namely, according to excitation-emission matrix analysis of stained protein bands, maximal fluorescence intensity (at 345/460 nm) was 3.5-fold higher compared with the settings that were available on a commercial imager (395/525 nm). As a supplement, we present an upgrade of the previously described method for in-gel detection of non-heme iron-binding proteins that also employs potassium ferricyanide.

Authors
Pristov, JB; Opačić, M; Dimitrijević, M; Babić, N; Spasojević, I
MLA Citation
Pristov, JB, Opačić, M, Dimitrijević, M, Babić, N, and Spasojević, I. "A method for in-gel fluorescent visualization of proteins after native and sodium dodecyl sulfate polyacrylamide gel electrophoresis." Analytical biochemistry 480 (July 2015): 6-10.
PMID
25862081
Source
epmc
Published In
Analytical Biochemistry
Volume
480
Publish Date
2015
Start Page
6
End Page
10
DOI
10.1016/j.ab.2015.04.006

Hippocampal antioxidative system in mesial temporal lobe epilepsy.

OBJECTIVE: To examine antioxidative system in hippocampi of patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (mTLE-HS). METHODS: Activity and levels of antioxidative enzymes-catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), manganese superoxide dismutase (MnSOD), and copper-zinc superoxide dismutase (CuZnSOD)-were assessed in hippocampi of nine pharmacoresistant mTLE-HS patients (mean age 37.7 ± [standard deviation] 6.6 years) who underwent amygdalohippocampectomy, and in 10 hippocampi obtained via autopsy from five neurologically intact controls (mean age 34.4 ± 9.0 years). Subfield and cellular (neuron/astrocyte) distribution of CAT, GPx, and MnSOD was analyzed in detail using immunohistochemical staining. RESULTS: Sclerotic hippocampi showed drastically increased activity of hydrogen peroxide-removing enzymes, CAT (p < 0.001), GPx (p < 0.001), and GR (p < 0.001), and significantly higher protein levels of CAT (p = 0.006), GPx (p = 0.040), GR (p = 0.024), and MnSOD (p = 0.004), compared to controls. CAT immunofluorescence was located mainly in neurons in both controls and HS. Control hippocampi showed GPx staining in blood vessels and CA neurons. In HS, GPx-rich loci, representing bundles of astrocytes, emerged in different hippocampal regions, whereas the number of GPx-positive vessels was drastically decreased. Neurons with abnormal morphology and strong MnSOD immunofluorescence were present in all neuronal layers in HS. Small autofluorescent deposits, most likely lipofuscin, were observed, along with astrogliosis, in CA1 in HS. SIGNIFICANCE: Antioxidative system is upregulated in HS. This documents, for the first time, that epileptogenic hippocampi are exposed to oxidative stress. Our findings provide a basis for understanding the potential involvement of redox alterations in the pathology of epilepsy, and may open new pharmacologic perspectives for mTLE-HS treatment.

Authors
Ristić, AJ; Savić, D; Sokić, D; Bogdanović Pristov, J; Nestorov, J; Baščarević, V; Raičević, S; Savić, S; Spasojević, I
MLA Citation
Ristić, AJ, Savić, D, Sokić, D, Bogdanović Pristov, J, Nestorov, J, Baščarević, V, Raičević, S, Savić, S, and Spasojević, I. "Hippocampal antioxidative system in mesial temporal lobe epilepsy." Epilepsia 56.5 (May 2015): 789-799.
PMID
25864570
Source
epmc
Published In
Epilepsia
Volume
56
Issue
5
Publish Date
2015
Start Page
789
End Page
799
DOI
10.1111/epi.12981

The role of autophagy and lipolysis in survival of astrocytes under nutrient deprivation.

Astrocytes can survive nutrient deprivation (ND) for days. However, the pro-survival strategy of astrocytes under such a metabolic challenge is still not clear. In the present study, we examined the effects of inhibition of two potential steps in energy acquisition during ND: autophagy (using chloroquine) and lipolysis (using orlistat). The inhibition of autophagy did not show significant effects on cell viability until 8-9h of ND. From that point onwards, the number of dead cells gradually increased, reaching ∼60% between 10 and 12h of ND. In addition, early inhibition of autophagy made astrocytes more vulnerable to the latter ND. The inhibition of lipolysis decreased the viability of cells exposed to ND, but this appeared much later compared to the inhibition of autophagy. The application of orlistat prevented ND-related hyperpolarization of the mitochondrial membrane, and mitochondria became swollen. This study clearly shows that autophagy and lipolysis are essential for the survival of astrocytes under ND conditions, which might be related to their role as neuron-supporting cells.

Authors
Korenić, A; Andjus, P; Radenović, L; Spasojević, I
MLA Citation
Korenić, A, Andjus, P, Radenović, L, and Spasojević, I. "The role of autophagy and lipolysis in survival of astrocytes under nutrient deprivation." Neuroscience letters 595 (May 2015): 128-133.
PMID
25888813
Source
epmc
Published In
Neuroscience Letters
Volume
595
Publish Date
2015
Start Page
128
End Page
133
DOI
10.1016/j.neulet.2015.04.020

The relationship of physicochemical properties to the antioxidative activity of free amino acids in Fenton system.

Herein we compared antioxidative activities (AA) of 25 free L-amino acids (FAA) against Fenton system-mediated hydroxyl radical (HO(•)) production in aqueous solution, and examined the relation between AA and a set of physicochemical properties. The rank order according to AA was: Trp > norleucine > Phe, Leu > Ile > His >3,4-dihydroxyphenylalanine, Arg > Val > Lys, Tyr, Pro > hydroxyproline > α-aminobutyric acid > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Sulfur-containing FAA generated different secondary reactive products, which were discriminated by the means of electron paramagnetic resonance spin-trapping spectroscopy. AA showed a general positive correlation with hydrophobicity. However, when taken separately, uncharged FAA exhibited strong positive correlation of AA with hydrophobicity whereas charged FAA showed negative or no significant correlation depending on the scale applied. A general strong negative correlation was found between AA and polarity. Steric parameters and hydration numbers correlated positively with AA of nonpolar side-chain FAA. In addition, a decrease of temperature which promotes hydrophobic hydration resulted in increased AA. This implies that HO(•)-provoked oxidation of FAA is strongly affected by hydrophobic hydration. Our findings are important for the understanding of oxidation processes in natural and waste waters.

Authors
Milić, S; Bogdanović Pristov, J; Mutavdžić, D; Savić, A; Spasić, M; Spasojević, I
MLA Citation
Milić, S, Bogdanović Pristov, J, Mutavdžić, D, Savić, A, Spasić, M, and Spasojević, I. "The relationship of physicochemical properties to the antioxidative activity of free amino acids in Fenton system." Environmental science & technology 49.7 (April 2015): 4245-4254.
PMID
25764263
Source
epmc
Published In
Environmental Science & Technology
Volume
49
Issue
7
Publish Date
2015
Start Page
4245
End Page
4254
DOI
10.1021/es5053396

Ex vivo effects of ibogaine on the activity of antioxidative enzymes in human erythrocytes.

Ibogaine is a naturally occurring alkaloid with psychotropic and metabotropic effects, derived from the bark of the root of the West African Tabernanthe iboga plant. The tribes of Kongo basin have been using iboga as a stimulant, for medicinal purposes, and in rite of passage ceremonies, for centuries. Besides, it has been found that this drug has anti-addictive effects.Previous studies have demonstrated that ibogaine changed the quantity of ATP and energy related enzymes as well as the activity of antioxidant enzymes in cells thus altering redox equilibrium in a time manner. In this work, the mechanism of its action was further studied by measuring the effects of ibogaine in human erythrocytes in vitro on ATP liberation, membrane fluidity and antioxidant enzymes activity.Heparinized human blood samples were incubated with ibogaine (10 and 20 μM) at 37°C for 1h. Blood plasma was separated by centrifugation and the levels of ATP and uric acid were measured 10 min after the addition of ibogaine using standard kits. The activity of copper-zinc superoxide dismutase (SOD1), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) were measured in erythrocytes after incubation period. The stability of SOD1 activity was further tested through in vitro incubation with H2O2 and scanning of its electrophoretic profiles. Membrane fluidity was determined using an electron paramagnetic resonance spin-labelling method.Results showed that ibogaine treatment of erythrocytes in vitro increased ATP concentration in the blood plasma without changes in neither erythrocytes membrane fluidity nor uric acid concentration. Ibogaine also increased SOD1 activity in erythrocytes at both doses applied here. Treatment with 20 μM also elevated GR activity after in vitro incubation at 37°C. Electrophoretic profiles revealed that incubation with ibogaine mitigates H2O2 mediated suppression of SOD1 activity.Some of the effects of ibogaine seem to be mediated through its influence on energy metabolism, redox active processes and the effects of discrete fluctuations of individual reactive oxygen species on different levels of enzyme activities. Overall, ibogaine acts as a pro-antioxidant by increasing activity of antioxidative enzymes and as an adaptagene in oxidative distress.

Authors
Nikolić-Kokić, A; Oreščanin-Dušić, Z; Spasojević, I; Slavić, M; Mijušković, A; Paškulin, R; Miljević, Č; Spasić, MB; Blagojević, DP
MLA Citation
Nikolić-Kokić, A, Oreščanin-Dušić, Z, Spasojević, I, Slavić, M, Mijušković, A, Paškulin, R, Miljević, Č, Spasić, MB, and Blagojević, DP. "Ex vivo effects of ibogaine on the activity of antioxidative enzymes in human erythrocytes." Journal of ethnopharmacology 164 (April 2015): 64-70.
PMID
25660330
Source
epmc
Published In
Journal of Ethnopharmacology
Volume
164
Publish Date
2015
Start Page
64
End Page
70
DOI
10.1016/j.jep.2015.01.037

Antineoplastic drug exposure in an ambulatory setting: a pilot study.

Exposure to antineoplastic drugs confers health risks to workers, yet little is known about the exposure after a drug spill, nor has the relationship between exposure and organizational factors such as staffing and work environment been studied.The aim of this study was to evaluate drug spills prospectively using biological measures and correlate drug spills with organizational factors.Prospective questionnaires with 8-hour timed urine samples were collected from nursing and pharmacy personnel who reported drug spill events in 1 academic health center's infusion center. Urine was collected similarly from workers who did not report a spill. Liquid chromatography tandem mass spectrometry techniques identified detectable drug levels. After the prospective sampling period, workers were surveyed on workloads, practice environment, and safety behaviors.From 81 eligible individuals, 40 participated in the prospective study and 19 completed retrospective questionnaires. Four spills were reported by 9 personnel, as multiple employees were exposed to drug spills. Four participants who reported a spill showed detectable levels of antineoplastic drugs. Four participants who did not report a spill had detectable levels of docetaxel. Compared with respondents who did not report a spill, collegial relations with physicians were significantly poorer for workers who reported spills.The study protocol successfully captured drug spill reports and biological samples. Workers have detectable levels of antineoplastic drugs through both drug spills and environmental contamination.Multisite research studies and practice-based quality improvement approaches are needed to improve adherence to personal protective equipment use and safe handling procedures.

Authors
Friese, CR; McArdle, C; Zhao, T; Sun, D; Spasojevic, I; Polovich, M; McCullagh, MC
MLA Citation
Friese, CR, McArdle, C, Zhao, T, Sun, D, Spasojevic, I, Polovich, M, and McCullagh, MC. "Antineoplastic drug exposure in an ambulatory setting: a pilot study." Cancer nursing 38.2 (March 2015): 111-117.
PMID
24831047
Source
epmc
Published In
Cancer Nursing
Volume
38
Issue
2
Publish Date
2015
Start Page
111
End Page
117
DOI
10.1097/ncc.0000000000000143

A comparative analysis of multiple sclerosis-relevant anti-inflammatory properties of ethyl pyruvate and dimethyl fumarate.

Dimethyl fumarate (DMF), a new drug for multiple sclerosis (MS) treatment, acts against neuroinflammation via mechanisms that are triggered by adduct formation with thiol redox switches. Ethyl pyruvate (EP), an off-the-shelf agent, appears to be a redox analog of DMF, but its immunomodulatory properties have not been put into the context of MS therapy. In this article, we examined and compared the effects of EP and DMF on MS-relevant activity/functions of T cells, macrophages, microglia, and astrocytes. EP efficiently suppressed the release of MS signature cytokines, IFN-γ and IL-17, from human PBMCs. Furthermore, the production of these cytokines was notably decreased in encephalitogenic T cells after in vivo application of EP to rats. Production of two other proinflammatory cytokines, IL-6 and TNF, and NO was suppressed by EP in macrophages and microglia. Reactive oxygen species production in macrophages, microglia activation, and the development of Ag-presenting phenotype in microglia and macrophages were constrained by EP. The release of IL-6 was reduced in astrocytes. Finally, EP inhibited the activation of transcription factor NF-κB in microglia and astrocytes. Most of these effects were also found for DMF, implying that EP and DMF share common targets and mechanisms of action. Importantly, EP had in vivo impact on experimental autoimmune encephalomyelitis, an animal model of MS. Treatment with EP resulted in delay and shortening of the first relapse, and lower clinical scores, whereas the second attack was annihilated. Further studies on the possibility to use EP as an MS therapeutic are warranted.

Authors
Miljković, D; Blaževski, J; Petković, F; Djedović, N; Momčilović, M; Stanisavljević, S; Jevtić, B; Mostarica Stojković, M; Spasojević, I
MLA Citation
Miljković, D, Blaževski, J, Petković, F, Djedović, N, Momčilović, M, Stanisavljević, S, Jevtić, B, Mostarica Stojković, M, and Spasojević, I. "A comparative analysis of multiple sclerosis-relevant anti-inflammatory properties of ethyl pyruvate and dimethyl fumarate." Journal of immunology (Baltimore, Md. : 1950) 194.6 (March 2015): 2493-2503.
PMID
25681336
Source
epmc
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
194
Issue
6
Publish Date
2015
Start Page
2493
End Page
2503
DOI
10.4049/jimmunol.1402302

Comparative analysis of antioxidative systems in malignant and benign brain tumours.

Comparison of redox conditions in malignant and benign tumours is essential for understanding the role of reactive oxygen species in the pathophysiology of aggressive cancer profiles. Here we compare antioxidative systems in highly malignant brain tumour - glioblastoma multiforme (GBM), and in meningioma, a benign brain tumour.Tumour tissues and blood of 67 GBM patients (mean age: 52.9 ± 11.5 years) and 67 meningioma patients (59.2 ± 10.2 years), and blood of 30 control subjects (50.8 ± 12.8 years) were analysed via biochemical assays.Components of glutathione system, which is responsible for H2O2 removal, showed lower activity/level in GBM: glutathione peroxidase (GBM: 9.90 ± 0.22; meningioma: 11.78 ± 0.23 U/mg of proteins; P < 0.001), glutathione reductase (GBM: 3.83 ± 0.13; meningioma: 4.67 ± 0.11 U/mg of proteins; P < 0.001), and glutathione (GBM: 6.70 ± 0.12; meningioma: 7.58 ± 0.14 μmol/g of tissue; P < 0.001). In contrast, the rank order of glutathione reductase activity and glutathione level in erythrocytes was: GBM > meningioma > control. Superoxide dismutase and catalase activities were lower in the blood of cancer patients compared to controls.Cells of malignant brain tumour show down-regulated antioxidative system which might result in increased levels of H2O2 compared to benign tumour tissue.

Authors
Bogosavljević, V; Bajčetić, M; Spasojević, I
MLA Citation
Bogosavljević, V, Bajčetić, M, and Spasojević, I. "Comparative analysis of antioxidative systems in malignant and benign brain tumours." Redox report : communications in free radical research 20.2 (March 2015): 69-74.
PMID
25247681
Source
epmc
Published In
Redox Report
Volume
20
Issue
2
Publish Date
2015
Start Page
69
End Page
74
DOI
10.1179/1351000214y.0000000106

Antineoplastic drug exposure in an ambulatory setting: A pilot study

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Background: Exposure to antineoplastic drugs confers health risks to workers, yet little is known about the exposure after a drug spill, nor has the relationship between exposure and organizational factors such as staffing and work environment been studied. Objective: The aim of this study was to evaluate drug spills prospectively using biological measures and correlate drug spills with organizational factors. Methods: Prospective questionnaires with 8-hour timed urine samples were collected from nursing and pharmacy personnel who reported drug spill events in 1 academic health center's infusion center. Urine was collected similarly from workers who did not report a spill. Liquid chromatography tandem mass spectrometry techniques identified detectable drug levels. After the prospective sampling period, workers were surveyed on workloads, practice environment, and safety behaviors. Results: From 81 eligible individuals, 40 participated in the prospective study and 19 completed retrospective questionnaires. Four spills were reported by 9 personnel, as multiple employees were exposed to drug spills. Four participants who reported a spill showed detectable levels of antineoplastic drugs. Four participants who did not report a spill had detectable levels of docetaxel. Compared with respondents who did not report a spill, collegial relations with physicians were significantly poorer for workers who reported spills. Conclusions: The study protocol successfully captured drug spill reports and biological samples. Workers have detectable levels of antineoplastic drugs through both drug spills and environmental contamination. Implications for Practice: Multisite research studies and practice-based quality improvement approaches are needed to improve adherence to personal protective equipment use and safe handling procedures.

Authors
Friese, CR; McArdle, C; Zhao, T; Sun, D; Spasojevic, I; Polovich, M; McCullagh, MC
MLA Citation
Friese, CR, McArdle, C, Zhao, T, Sun, D, Spasojevic, I, Polovich, M, and McCullagh, MC. "Antineoplastic drug exposure in an ambulatory setting: A pilot study." Cancer Nursing 38.2 (January 1, 2015): 111-117.
Source
scopus
Published In
Cancer Nursing
Volume
38
Issue
2
Publish Date
2015
Start Page
111
End Page
117
DOI
10.1097/NCC.0000000000000143

Radioprotection of the brain white matter by Mn(III) n-Butoxyethylpyridylporphyrin-based superoxide dismutase mimic MnTnBuOE-2-PyP5+.

Cranial irradiation is a standard therapy for primary and metastatic brain tumors. A major drawback of radiotherapy (RT), however, is long-term cognitive loss that affects quality of life. Radiation-induced oxidative stress in normal brain tissue is thought to contribute to cognitive decline. We evaluated the effectiveness of a novel mimic of superoxide dismutase enzyme (SOD), MnTnBuOE-2-PyP(5+)(Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin), to provide long-term neuroprotection following 8 Gy of whole brain irradiation. Long-term RT damage can only be assessed by brain imaging and neurocognitive studies. C57BL/6J mice were treated with MnTnBuOE-2-PyP(5+) before and after RT and evaluated three months later. At this time point, drug concentration in the brain was 25 nmol/L. Mice treated with MnTnBuOE-2-PyP(5+)/RT exhibited MRI evidence for myelin preservation in the corpus callosum compared with saline/RT treatment. Corpus callosum histology demonstrated a significant loss of axons in the saline/RT group that was rescued in the MnTnBuOE-2-PyP(5+)/RT group. In addition, the saline/RT groups exhibited deficits in motor proficiency as assessed by the rotorod test and running wheel tests. These deficits were ameliorated in groups treated with MnTnBuOE-2-PyP(5+)/RT. Our data demonstrate that MnTnBuOE-2-PyP(5+) is neuroprotective for oxidative stress damage caused by radiation exposure. In addition, glioblastoma cells were not protected by MnTnBuOE-2-PyP(5+) combination with radiation in vitro. Likewise, the combination of MnTnBuOE-2-PyP(5+) with radiation inhibited tumor growth more than RT alone in flank tumors. In summary, MnTnBuOE-2-PyP(5+) has dual activity as a neuroprotector and a tumor radiosensitizer. Thus, it is an attractive candidate for adjuvant therapy with RT in future studies with patients with brain cancer.

Authors
Weitzel, DH; Tovmasyan, A; Ashcraft, KA; Rajic, Z; Weitner, T; Liu, C; Li, W; Buckley, AF; Prasad, MR; Young, KH; Rodriguiz, RM; Wetsel, WC; Peters, KB; Spasojevic, I; Herndon, JE; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Weitzel, DH, Tovmasyan, A, Ashcraft, KA, Rajic, Z, Weitner, T, Liu, C, Li, W, Buckley, AF, Prasad, MR, Young, KH, Rodriguiz, RM, Wetsel, WC, Peters, KB, Spasojevic, I, Herndon, JE, Batinic-Haberle, I, and Dewhirst, MW. "Radioprotection of the brain white matter by Mn(III) n-Butoxyethylpyridylporphyrin-based superoxide dismutase mimic MnTnBuOE-2-PyP5+." Molecular cancer therapeutics 14.1 (January 2015): 70-79.
PMID
25319393
Source
epmc
Published In
Molecular cancer therapeutics
Volume
14
Issue
1
Publish Date
2015
Start Page
70
End Page
79
DOI
10.1158/1535-7163.mct-14-0343

A high-throughput in vitro drug screen in a genetically engineered mouse model of diffuse intrinsic pontine glioma identifies BMS-754807 as a promising therapeutic agent.

Diffuse intrinsic pontine gliomas (DIPGs) represent a particularly lethal type of pediatric brain cancer with no effective therapeutic options. Our laboratory has previously reported the development of genetically engineered DIPG mouse models using the RCAS/tv-a system, including a model driven by PDGF-B, H3.3K27M, and p53 loss. These models can serve as a platform in which to test novel therapeutics prior to the initiation of human clinical trials. In this study, an in vitro high-throughput drug screen as part of the DIPG preclinical consortium using cell-lines derived from our DIPG models identified BMS-754807 as a drug of interest in DIPG. BMS-754807 is a potent and reversible small molecule multi-kinase inhibitor with many targets including IGF-1R, IR, MET, TRKA, TRKB, AURKA, AURKB. In vitro evaluation showed significant cytotoxic effects with an IC50 of 0.13 μM, significant inhibition of proliferation at a concentration of 1.5 μM, as well as inhibition of AKT activation. Interestingly, IGF-1R signaling was absent in serum-free cultures from the PDGF-B; H3.3K27M; p53 deficient model suggesting that the antitumor activity of BMS-754807 in this model is independent of IGF-1R. In vivo, systemic administration of BMS-754807 to DIPG-bearing mice did not prolong survival. Pharmacokinetic analysis demonstrated that tumor tissue drug concentrations of BMS-754807 were well below the identified IC50, suggesting that inadequate drug delivery may limit in vivo efficacy. In summary, an unbiased in vitro drug screen identified BMS-754807 as a potential therapeutic agent in DIPG, but BMS-754807 treatment in vivo by systemic delivery did not significantly prolong survival of DIPG-bearing mice.

Authors
Halvorson, KG; Barton, KL; Schroeder, K; Misuraca, KL; Hoeman, C; Chung, A; Crabtree, DM; Cordero, FJ; Singh, R; Spasojevic, I; Berlow, N; Pal, R; Becher, OJ
MLA Citation
Halvorson, KG, Barton, KL, Schroeder, K, Misuraca, KL, Hoeman, C, Chung, A, Crabtree, DM, Cordero, FJ, Singh, R, Spasojevic, I, Berlow, N, Pal, R, and Becher, OJ. "A high-throughput in vitro drug screen in a genetically engineered mouse model of diffuse intrinsic pontine glioma identifies BMS-754807 as a promising therapeutic agent." PloS one 10.3 (January 2015): e0118926-.
Website
http://hdl.handle.net/10161/12567
PMID
25748921
Source
epmc
Published In
PloS one
Volume
10
Issue
3
Publish Date
2015
Start Page
e0118926
DOI
10.1371/journal.pone.0118926

Urinary F2-isoprostanes and metabolic markers of fat oxidation.

Metabolomic studies of increased fat oxidation showed increase in circulating acylcarnitines C2, C8, C10, and C12 and decrease in C3, C4, and C5. We hypothesize that urinary F2-isoprostanes reflect intensity of fatty acid oxidation and are associated with circulating C2, C8, C10, and C12 directly and with C3, C4, and C5 inversely. Four urinary F2-isoprostane isomers and serum acylcarnitines are quantified using LC-MS/MS within the Insulin Resistance Atherosclerosis Study nondiabetic cohort (n = 682). Cross-sectional associations between fasting urinary F2-isoprostanes (summarized as a composite index) and the selected acylcarnitines are examined using generalized linear models. F2-isoprostane index is associated with C2 and C12 directly and with C5 inversely: the adjusted beta coefficients are 0.109, 0.072, and -0.094, respectively (P < 0.05). For these acylcarnitines and for F2-isoprostanes, the adjusted odds ratios (ORs) of incident diabetes are calculated from logistic regression models: the ORs (95% CI) are 0.77 (0.60-0.97), 0.79 (0.62-1.01), 1.18 (0.92-1.53), and 0.51 (0.35-0.76) for C2, C12, C5, and F2-isoprostanes, respectively. The direction of the associations between urinary F2-isoprostanes and three acylcarnitines (C2, C5, and C12) supports our hypothesis. The inverse associations of C2 and C12 and with incident diabetes are consistent with the suggested protective role of efficient fat oxidation.

Authors
Il'yasova, D; Wagenknecht, LE; Spasojevic, I; Watkins, S; Bowden, D; Wang, F; D'Agostino, RB
MLA Citation
Il'yasova, D, Wagenknecht, LE, Spasojevic, I, Watkins, S, Bowden, D, Wang, F, and D'Agostino, RB. "Urinary F2-isoprostanes and metabolic markers of fat oxidation." Oxidative medicine and cellular longevity 2015 (January 2015): 729191-.
PMID
25802683
Source
epmc
Published In
Oxidative Medicine and Cellular Longevity
Volume
2015
Publish Date
2015
Start Page
729191
DOI
10.1155/2015/729191

The effects of wild-type and mutant SOD1 on smooth muscle contraction

Authors
Nikolic-Kokic, A; Orescanin-Dusic, Z; Spasojevic, I; Blagojevic, D; Stevic, Z; Andjus, P; Spasic, M
MLA Citation
Nikolic-Kokic, A, Orescanin-Dusic, Z, Spasojevic, I, Blagojevic, D, Stevic, Z, Andjus, P, and Spasic, M. "The effects of wild-type and mutant SOD1 on smooth muscle contraction." Archives of Biological Sciences 67.1 (2015): 187-192.
Source
crossref
Published In
Archives of Biological Sciences
Volume
67
Issue
1
Publish Date
2015
Start Page
187
End Page
192
DOI
10.2298/ABS141006023N

Novel amphiphilic cationic porphyrin and its Ag(II) complex as potential anticancer agents.

In the present study we have synthesized a novel amphiphilic porphyrin and its Ag(II) complex through modification of water-soluble porphyrinic structure in order to increase its lipophilicity and in turn pharmacological potency. New cationic non-symmetrical meso-substituted porphyrins were characterized by UV-visible, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR techniques, lipophilicity (thin-layer chromatographic retention factor, Rf), and elemental analysis. The key toxicological profile (i.e. cytotoxicity and cell line- (cancer type-) specificity; genotoxicity; cell cycle effects) of amphiphilic Ag porphyrin was studied in human normal and cancer cell lines of various tissue origins and compared with its water-soluble analog. Structural modification of the molecule from water-soluble to amphiphilic resulted in a certain increase in the cytotoxicity and a decrease in cell line-specificity. Importantly, Ag(II) porphyrin showed less toxicity to normal cells and greater toxicity to their cancerous counterparts as compared to cisplatin. The amphiphilic complex was also not genotoxic and demonstrated a slight cytostatic effect via the cell cycle delay due to the prolongation of S-phase. As expected, the performed structural modification affected also the photocytotoxic activity of metal-free amphiphilic porphyrin. The ligand tested on cancer cell line revealed a dramatic (more than 70-fold) amplification of its phototoxic activity as compared to its water-soluble tetracationic metal-free analog. The compound combines low dark cytotoxicity with 5 fold stronger phototoxicity relative to Chlorin e6 and could be considered as a potential photosensitizer for further development in photodynamic therapy.

Authors
Tovmasyan, A; Babayan, N; Poghosyan, D; Margaryan, K; Harutyunyan, B; Grigoryan, R; Sarkisyan, N; Spasojevic, I; Mamyan, S; Sahakyan, L; Aroutiounian, R; Ghazaryan, R; Gasparyan, G
MLA Citation
Tovmasyan, A, Babayan, N, Poghosyan, D, Margaryan, K, Harutyunyan, B, Grigoryan, R, Sarkisyan, N, Spasojevic, I, Mamyan, S, Sahakyan, L, Aroutiounian, R, Ghazaryan, R, and Gasparyan, G. "Novel amphiphilic cationic porphyrin and its Ag(II) complex as potential anticancer agents." Journal of inorganic biochemistry 140 (November 2014): 94-103.
PMID
25086237
Source
epmc
Published In
Journal of Inorganic Biochemistry
Volume
140
Publish Date
2014
Start Page
94
End Page
103
DOI
10.1016/j.jinorgbio.2014.06.013

Rational design of superoxide dismutase (SOD) mimics: the evaluation of the therapeutic potential of new cationic Mn porphyrins with linear and cyclic substituents.

Our goal herein has been to gain further insight into the parameters which control porphyrin therapeutic potential. Mn porphyrins (MnTnOct-2-PyP(5+), MnTnHexOE-2-PyP(5+), MnTE-2-PyPhP(5+), and MnTPhE-2-PyP(5+)) that bear the same positive charge and same number of carbon atoms at meso positions of porphyrin core were explored. The carbon atoms of their meso substituents are organized to form either linear or cyclic structures of vastly different redox properties, bulkiness, and lipophilicities. These Mn porphyrins were compared to frequently studied compounds, MnTE-2-PyP(5+), MnTE-3-PyP(5+), and MnTBAP(3-). All Mn(III) porphyrins (MnPs) have metal-centered reduction potential, E1/2 for Mn(III)P/Mn(II)P redox couple, ranging from -194 to +340 mV versus NHE, log kcat(O2(•-)) from 3.16 to 7.92, and log kred(ONOO(-)) from 5.02 to 7.53. The lipophilicity, expressed as partition between n-octanol and water, log POW, was in the range -1.67 to -7.67. The therapeutic potential of MnPs was assessed via: (i) in vitro ability to prevent spontaneous lipid peroxidation in rat brain homogenate as assessed by malondialdehyde levels; (ii) in vivo O2(•-) specific assay to measure the efficacy in protecting the aerobic growth of SOD-deficient Saccharomyces cerevisiae; and (iii) aqueous solution chemistry to measure the reactivity toward major in vivo endogenous antioxidant, ascorbate. Under the conditions of lipid peroxidation assay, the transport across the cellular membranes, and in turn shape and size of molecule, played no significant role. Those MnPs of E1/2 ∼ +300 mV were the most efficacious, significantly inhibiting lipid peroxidation in 0.5-10 μM range. At up to 200 μM, MnTBAP(3-) (E1/2 = -194 mV vs NHE) failed to inhibit lipid peroxidation, while MnTE-2-PyPhP(5+) with 129 mV more positive E1/2 (-65 mV vs NHE) was fully efficacious at 50 μM. The E1/2 of Mn(III)P/Mn(II)P redox couple is proportional to the log kcat(O2(•-)), i.e., the SOD-like activity of MnPs. It is further proportional to kred(ONOO(-)) and the ability of MnPs to prevent lipid peroxidation. In turn, the inhibition of lipid peroxidation by MnPs is also proportional to their SOD-like activity. In an in vivo S. cerevisiae assay, however, while E1/2 predominates, lipophilicity significantly affects the efficacy of MnPs. MnPs of similar log POW and E1/2, that have linear alkyl or alkoxyalkyl pyridyl substituents, distribute more easily within a cell and in turn provide higher protection to S. cerevisiae in comparison to MnP with bulky cyclic substituents. The bell-shape curve, with MnTE-2-PyP(5+) exhibiting the highest ability to catalyze ascorbate oxidation, has been established and discussed. Our data support the notion that the SOD-like activity of MnPs parallels their therapeutic potential, though species other than O2(•-), such as peroxynitrite, H2O2, lipid reactive species, and cellular reductants, may be involved in their mode(s) of action(s).

Authors
Tovmasyan, A; Carballal, S; Ghazaryan, R; Melikyan, L; Weitner, T; Maia, CGC; Reboucas, JS; Radi, R; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Carballal, S, Ghazaryan, R, Melikyan, L, Weitner, T, Maia, CGC, Reboucas, JS, Radi, R, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Rational design of superoxide dismutase (SOD) mimics: the evaluation of the therapeutic potential of new cationic Mn porphyrins with linear and cyclic substituents." Inorganic chemistry 53.21 (November 2014): 11467-11483.
PMID
25333724
Source
epmc
Published In
Inorganic Chemistry
Volume
53
Issue
21
Publish Date
2014
Start Page
11467
End Page
11483
DOI
10.1021/ic501329p

Rational Design of New Cationic Mn Porphyrins and Evaluation of Their Therapeutic Potential

Authors
Tovmasyan, A; Carballal, S; Ghazaryan, R; Melikyan, L; Weitner, T; Maia, CG; Reboucas, JS; Radi, R; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Carballal, S, Ghazaryan, R, Melikyan, L, Weitner, T, Maia, CG, Reboucas, JS, Radi, R, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Rational Design of New Cationic Mn Porphyrins and Evaluation of Their Therapeutic Potential." Free Radical Biology and Medicine 76 (November 2014): S94-S94.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S94
End Page
S94
DOI
10.1016/j.freeradbiomed.2014.10.326

Redox therapy in neonatal sepsis: reasons, targets, strategy, and agents.

Neonatal sepsis is one of the most fulminating conditions in neonatal intensive care units. Antipathogen and supportive care are administered routinely, but do not deliver satisfactory results. In addition, the efforts to treat neonatal sepsis with anti-inflammatory agents have generally shown to be futile. The accumulating data imply that intracellular redox changes intertwined into neonatal sepsis redox cycle represent the main cause of dysfunction of mitochondria and cells in neonatal sepsis. Our aim here is to support the new philosophy in neonatal sepsis treatment, which involves the integration of mechanisms that are responsible for cellular dysfunction and organ failure, the recognition of the most important targets, and the selection of safe agents that can stop the neonatal sepsis redox cycle by hitting the hot spots. Redox-active agents that could be beneficial for neonatal sepsis treatment according to these criteria include lactoferrin, interleukin 10, zinc and selenium supplements, ibuprofen, edaravone, and pentoxifylline.

Authors
Bajčetić, M; Spasić, S; Spasojević, I
MLA Citation
Bajčetić, M, Spasić, S, and Spasojević, I. "Redox therapy in neonatal sepsis: reasons, targets, strategy, and agents." Shock (Augusta, Ga.) 42.3 (September 2014): 179-184. (Review)
PMID
24827393
Source
epmc
Published In
Shock
Volume
42
Issue
3
Publish Date
2014
Start Page
179
End Page
184
DOI
10.1097/shk.0000000000000198

Antioxidative system in the erythrocytes of preterm neonates with sepsis: the effects of vitamin E supplementation.

BACKGROUND: Vitamin E is routinely supplemented to preterm babies, including those with neonatal sepsis. Our aim was to examine the effects of neonatal sepsis and vitamin E on antioxidative system (AOS) in the blood. METHODS: A prospective, randomized, open label study involved 65 preterm neonates (control/sepsis - 34/31), which were divided into two subgroups - non-supplemented and supplemented with vitamin E (25 IU/day for 60 days). The activities of superoxide dismutase, catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) were determined in erythrocytes at days 0, 30, and 60, following sepsis diagnosis. RESULTS: There was no difference in the activity of AOS between controls and neonates with ongoing sepsis. At 60 days, septic neonates showed higher CAT activity compared to controls (P = 0.027), and lower GPx activity compared to 0 days (P = 0.022). The later was mitigated by vitamin E, which on the other hand provoked lower GPx activity at 30 days, compared to untreated septic neonates (P = 0.014). In addition, vitamin E suppressed GR activity in septic neonates (P = 0.025 and P = 0.017 at 30 and 60 days). Finally, vitamin E supplementation in control neonates provoked a significant increase of GPx activity (P = 0.015 at 60 days). CONCLUSIONS: The absence of altered redox settings in the blood of neonates during sepsis episode, and vitamin E-provoked decrease in the activity of some components of AOS, suggest that the supplementation of vitamin E in these patients might not be rational.

Authors
Bajčetić, M; Otašević, B; Prekajski, NB; Spasić, S; Spasojević, I
MLA Citation
Bajčetić, M, Otašević, B, Prekajski, NB, Spasić, S, and Spasojević, I. "Antioxidative system in the erythrocytes of preterm neonates with sepsis: the effects of vitamin E supplementation." Annals of clinical biochemistry 51.Pt 5 (September 2014): 550-556.
PMID
24081186
Source
epmc
Published In
Annals of Clinical Biochemistry
Volume
51
Issue
Pt 5
Publish Date
2014
Start Page
550
End Page
556
DOI
10.1177/0004563213503317

A joint analysis of metabolomics and genetics of breast cancer.

Remodeling of cellular metabolism appears to be a consequence and possibly a cause of oncogenic transformation in human cancers. Specific aspects of altered tumor metabolism may be amenable to therapeutic intervention and could be coordinated with other targeted therapies. In breast cancer, the genetic landscape has been defined most comprehensively in efforts such as The Cancer Genome Atlas (TCGA). However, little is known about how alterations of tumor metabolism correlate with this landscape.In total 25 cancers (23 fully analyzed by TCGA) and 5 normal breast specimens were analyzed by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry, quantitating 399 identifiable metabolites.We found strong differences correlated with hormone receptor status with 18% of the metabolites elevated in estrogen receptor negative (ER-) cancers compared to estrogen receptor positive (ER+) including many glycolytic and glycogenolytic intermediates consistent with increased Warburg effects. Glutathione (GSH) pathway components were also elevated in ER- tumors consistent with an increased requirement for handling higher levels of oxidative stress. Additionally, ER- tumors had high levels of the oncometabolite 2-hydroxyglutarate (2-HG) and the immunomodulatory tryptophan metabolite kynurenine. Kynurenine levels were correlated with the expression of tryptophan-degrading enzyme (IDO1). However, high levels of 2-HG were not associated with somatic mutations or expression levels of IDH1 or IDH2. BRCA1 mRNA levels were positively associated with coenzyme A, acetyl coenzyme A, and GSH and negatively associated with multiple lipid species, supporting the regulation of ACC1 and NRF2 by BRCA1. Different driver mutations were associated with distinct patterns of specific metabolites, such as lower levels of several lipid-glycerophosphocholines in tumors with mutated TP53. A strong metabolomic signature associated with proliferation rate was also observed; the metabolites in this signature overlap broadly with metabolites that define ER status as receptor status and proliferation rate were correlated.The addition of metabolomic profiles to the public domain TCGA dataset provides an important new tool for discovery and hypothesis testing of the genetic regulation of tumor metabolism. Particular sets of metabolites may reveal insights into the metabolic dysregulation that underlie the heterogeneity of breast cancer.

Authors
Tang, X; Lin, C-C; Spasojevic, I; Iversen, ES; Chi, J-T; Marks, JR
MLA Citation
Tang, X, Lin, C-C, Spasojevic, I, Iversen, ES, Chi, J-T, and Marks, JR. "A joint analysis of metabolomics and genetics of breast cancer." Breast cancer research : BCR 16.4 (August 5, 2014): 415-.
PMID
25091696
Source
epmc
Published In
Breast Cancer Research
Volume
16
Issue
4
Publish Date
2014
Start Page
415
DOI
10.1186/s13058-014-0415-9

Cancer-associated isocitrate dehydrogenase 1 (IDH1) R132H mutation and d-2-hydroxyglutarate stimulate glutamine metabolism under hypoxia.

Mutations in the cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDH1) occur in several types of cancer, and altered cellular metabolism associated with IDH1 mutations presents unique therapeutic opportunities. By altering IDH1, these mutations target a critical step in reductive glutamine metabolism, the metabolic pathway that converts glutamine ultimately to acetyl-CoA for biosynthetic processes. While IDH1-mutated cells are sensitive to therapies that target glutamine metabolism, the effect of IDH1 mutations on reductive glutamine metabolism remains poorly understood. To explore this issue, we investigated the effect of a knock-in, single-codon IDH1-R132H mutation on the metabolism of the HCT116 colorectal adenocarcinoma cell line. Here we report the R132H-isobolome by using targeted (13)C isotopomer tracer fate analysis to trace the metabolic fate of glucose and glutamine in this system. We show that introduction of the R132H mutation into IDH1 up-regulates the contribution of glutamine to lipogenesis in hypoxia, but not in normoxia. Treatment of cells with a d-2-hydroxyglutarate (d-2HG) ester recapitulated these changes, indicating that the alterations observed in the knocked-in cells were mediated by d-2HG produced by the IDH1 mutant. These studies provide a dynamic mechanistic basis for metabolic alterations observed in IDH1-mutated tumors and uncover potential therapeutic targets in IDH1-mutated cancers.

Authors
Reitman, ZJ; Duncan, CG; Poteet, E; Winters, A; Yan, L-J; Gooden, DM; Spasojevic, I; Boros, LG; Yang, S-H; Yan, H
MLA Citation
Reitman, ZJ, Duncan, CG, Poteet, E, Winters, A, Yan, L-J, Gooden, DM, Spasojevic, I, Boros, LG, Yang, S-H, and Yan, H. "Cancer-associated isocitrate dehydrogenase 1 (IDH1) R132H mutation and d-2-hydroxyglutarate stimulate glutamine metabolism under hypoxia." The Journal of Biological Chemistry 289.34 (August 2014): 23318-23328.
PMID
24986863
Source
epmc
Published In
The Journal of biological chemistry
Volume
289
Issue
34
Publish Date
2014
Start Page
23318
End Page
23328
DOI
10.1074/jbc.m114.575183

Comparison of the effects of methanethiol and sodium sulphide on uterine contractile activity.

BACKGROUND: Our aim was to investigate the effect of methanethiol (CH3SH) on contractility of rat uterus and activities of redox-active enzymes, and to compare them with the effect of sodium sulphide (Na2S), a hydrogen sulphide (H2S/HS(-)) donor. METHODS: Uteri were isolated from virgin Wistar rats, divided into six groups, controls (untreated uteri allowed to contract spontaneously and in the presence of Ca(2+)(6mM)), CH3SH treated (spontaneously active and Ca(2+) induced) and Na2S treated (spontaneously active and Ca(2+) induced). Underlying antioxidative enzyme activities (superoxide dismutase--SOD, glutathione peroxidase--GSHPx, glutathione reductase--GR) in CH3SH- or Na2S-treated uteri were compared to controls. RESULTS: Our experiments showed that CH3SH and Na2S provoked reversible relaxation of both spontaneous and Ca(2+)-induced uterine contractions. The dose-response curves differed in shape, and CH3SH curve was shifted to higher concentration compared to H2S/HS(-). The effects of Na2S fitted sigmoid curve, whereas those of CH3SH fitted linearly. CH3SH provoked increased SOD activity and decreased GR activity. However, Na2S (H2S/HS(-)) provoked an increase in SOD activity exclusively in Ca(2+)-stimulated uteri, while the activity of GSHPx was increased in both types of active uteri. CONCLUSION: Our results imply that CH3SH may have a constructive role in the control of muscle function and metabolism. Observed differences between CH3SH and H2S/HS(-) could be attributed to a larger moiety that is present in CH3SH compared to H2S, but they are more likely to be a consequence of the specific actions of HS(-), in relation to its negative charge.

Authors
Mijušković, A; Oreščanin-Dušić, Z; Nikolić-Kokić, A; Slavić, M; Spasić, MB; Spasojević, I; Blagojević, D
MLA Citation
Mijušković, A, Oreščanin-Dušić, Z, Nikolić-Kokić, A, Slavić, M, Spasić, MB, Spasojević, I, and Blagojević, D. "Comparison of the effects of methanethiol and sodium sulphide on uterine contractile activity." Pharmacological reports : PR 66.3 (June 2014): 373-379.
PMID
24905511
Source
epmc
Published In
Pharmacological Reports
Volume
66
Issue
3
Publish Date
2014
Start Page
373
End Page
379
DOI
10.1016/j.pharep.2013.12.012

SOD therapeutics: latest insights into their structure-activity relationships and impact on the cellular redox-based signaling pathways.

SIGNIFICANCE: Superoxide dismutase (SOD) enzymes are indispensable and ubiquitous antioxidant defenses maintaining the steady-state levels of O2·(-); no wonder, thus, that their mimics are remarkably efficacious in essentially any animal model of oxidative stress injuries thus far explored. RECENT ADVANCES: Structure-activity relationship (half-wave reduction potential [E1/2] versus log kcat), originally reported for Mn porphyrins (MnPs), is valid for any other class of SOD mimics, as it is dominated by the superoxide reduction and oxidation potential. The biocompatible E1/2 of ∼+300 mV versus normal hydrogen electrode (NHE) allows powerful SOD mimics as mild oxidants and antioxidants (alike O2·(-)) to readily traffic electrons among reactive species and signaling proteins, serving as fine mediators of redox-based signaling pathways. Based on similar thermodynamics, both SOD enzymes and their mimics undergo similar reactions, however, due to vastly different sterics, with different rate constants. CRITICAL ISSUES: Although log kcat(O2·(-)) is a good measure of therapeutic potential of SOD mimics, discussions of their in vivo mechanisms of actions remain mostly of speculative character. Most recently, the therapeutic and mechanistic relevance of oxidation of ascorbate and glutathionylation and oxidation of protein thiols by MnP-based SOD mimics and subsequent inactivation of nuclear factor κB has been substantiated in rescuing normal and killing cancer cells. Interaction of MnPs with thiols seems to be, at least in part, involved in up-regulation of endogenous antioxidative defenses, leading to the healing of diseased cells. FUTURE DIRECTIONS: Mechanistic explorations of single and combined therapeutic strategies, along with studies of bioavailability and translational aspects, will comprise future work in optimizing redox-active drugs.

Authors
Batinic-Haberle, I; Tovmasyan, A; Roberts, ERH; Vujaskovic, Z; Leong, KW; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, Roberts, ERH, Vujaskovic, Z, Leong, KW, and Spasojevic, I. "SOD therapeutics: latest insights into their structure-activity relationships and impact on the cellular redox-based signaling pathways." Antioxid Redox Signal 20.15 (May 20, 2014): 2372-2415. (Review)
PMID
23875805
Source
pubmed
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2372
End Page
2415
DOI
10.1089/ars.2012.5147

Complex chemistry and biology of redox-active compounds, commonly known as SOD mimics, affect their therapeutic effects.

This Editorial has the intention to stress the complex chemistry and biology of redox-active compounds, regarded as SOD mimics. It further aims to caution the researchers of the importance of being up-to-date with the present knowledge on such compounds and their cellular redox biology when coming up with their conclusions, based on the particular species involved in their studies.

Authors
Batinic-Haberle, I; Spasojevic, I
MLA Citation
Batinic-Haberle, I, and Spasojevic, I. "Complex chemistry and biology of redox-active compounds, commonly known as SOD mimics, affect their therapeutic effects." Antioxidants & redox signaling 20.15 (May 2014): 2323-2325.
PMID
24650329
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2323
End Page
2325
DOI
10.1089/ars.2014.5921

Manganese-based superoxide dismutase mimics modify both acute and long-term outcome severity in a Drosophila melanogaster model of classic galactosemia.

The goal of this study was to use two manganese (Mn)-based superoxide dismutase (SOD) mimics to test the hypothesis that reactive oxygen species contribute to both acute and long-term outcomes in a galactose-1P uridylyltransferase (GALT)-null Drosophila melanogaster model of classic galactosemia.We tested the impact of each of two Mn porphyrin SOD mimics, MnTnBuOE-2-PyP(5+), and MnTE-2-PyP(5+), (i) on survival of GALT-null Drosophila larvae reared in the presence versus absence of dietary galactose and (ii) on the severity of a long-term movement defect in GALT-null adult flies. Both SOD mimics conferred a significant survival benefit to GALT-null larvae exposed to galactose but not to controls or to GALT-null larvae reared in the absence of galactose. One mimic, MnTE-2-PyP(5+), also largely rescued a galactose-independent long-term movement defect otherwise seen in adult GALT-null flies. The survival benefit of both SOD mimics occurred despite continued accumulation of elevated galactose-1P in the treated animals, and studies of thiolated proteins demonstrated that in both the presence and absence of dietary galactose MnTE-2-PyP(5+) largely prevented the elevated protein oxidative damage otherwise seen in GALT-null animals relative to controls.Our results confirm oxidative stress as a mediator of acute galactose sensitivity in GALT-null Drosophila larvae and demonstrate for the first time that oxidative stress may also contribute to galactose-independent adult outcomes in GALT deficiency. Finally, our results demonstrate for the first time that both MnTnBuOE-2-PyP(5+) and MnTE-2-PyP(5+) are bioavailable and effective when administered through an oral route in a D. melanogaster model of classic galactosemia.

Authors
Jumbo-Lucioni, PP; Ryan, EL; Hopson, ML; Bishop, HM; Weitner, T; Tovmasyan, A; Spasojevic, I; Batinic-Haberle, I; Liang, Y; Jones, DP; Fridovich-Keil, JL
MLA Citation
Jumbo-Lucioni, PP, Ryan, EL, Hopson, ML, Bishop, HM, Weitner, T, Tovmasyan, A, Spasojevic, I, Batinic-Haberle, I, Liang, Y, Jones, DP, and Fridovich-Keil, JL. "Manganese-based superoxide dismutase mimics modify both acute and long-term outcome severity in a Drosophila melanogaster model of classic galactosemia." Antioxidants & redox signaling 20.15 (May 2014): 2361-2371.
PMID
23758052
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2361
End Page
2371
DOI
10.1089/ars.2012.5122

Metals and electrolytes in sclerotic hippocampi in patients with drug-resistant mesial temporal lobe epilepsy.

An altered metal and electrolyte profile has been implicated in the pathologic mechanisms of chronic epilepsy; however, no study has comprehensively measured hippocampal concentrations of these elements in patients with mesial temporal lobe epilepsy and hippocampal sclerosis (mTLE-HS). We therefore analyzed hippocampi of 24 patients with drug-resistant mTLE-HS (mean age 35.6 ± 9.4 years) who underwent anterior temporal lobe resection and amygdalohippocampectomy and 17 hippocampi obtained by autopsy from 13 controls (mean age 40.5 ± 12.9 years), using inductively coupled plasma optical emission spectrometry (ICP-OES). Epileptic hippocampi showed significantly lower concentrations (μg/g of tissue) of copper (HS: 2.34 ± 0.12; control [C]: 3.57 ± 0.33; p < 0.001), manganese (HS: 0.205 ± 0.030; C: 0.409 ± 0.064; p = 0.004), and potassium (HS: 2,001 ± 59; C: 2,322 ± 61; p < 0.001), and increased sodium levels (HS: 1,131 ± 22; C: 1,040 ± 25; p = 0.010). Zinc, iron, calcium, and magnesium levels did not differ in HS and controls. In summary, copper and manganese levels are deficient, whereas iron level is unchanged in hippocampi from patients with mTLE-HS. Our results provide a basis for understanding the potential involvement of different metals and electrolytes in the pathology of HS.

Authors
Ristić, AJ; Sokić, D; Baščarević, V; Spasić, S; Vojvodić, N; Savić, S; Raičević, S; Kovačević, M; Savić, D; Spasojević, I
MLA Citation
Ristić, AJ, Sokić, D, Baščarević, V, Spasić, S, Vojvodić, N, Savić, S, Raičević, S, Kovačević, M, Savić, D, and Spasojević, I. "Metals and electrolytes in sclerotic hippocampi in patients with drug-resistant mesial temporal lobe epilepsy." Epilepsia 55.5 (May 2014): e34-e37.
PMID
24673751
Source
epmc
Published In
Epilepsia
Volume
55
Issue
5
Publish Date
2014
Start Page
e34
End Page
e37
DOI
10.1111/epi.12593

Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae.

Cationic Mn(III) porphyrin complexes based on MnTM-2-PyP are among the most promising superoxide dismutase (SOD) mimicking compounds being considered as potential anti-inflammatory drugs. We studied four of these active compounds in the yeast Saccharomyces cerevisiae, MnTM-2-PyP, MnTE-2-PyP, MnTnHex-2-PyP, and MnTnBu-2-PyP, each of which differs only in the length of its alkyl substituents. Each was active in improving the aerobic growth of yeast lacking SOD (sod1∆) in complete medium, and the efficacy of each mimic was correlated with its characteristic catalytic activity. We also studied the partitioning of these compounds between mitochondria and cytosol and found that the more hydrophobic members of the series accumulated in the mitochondria. Moreover, the degree to which a mimic mitigated the sod1Δ auxotrophic phenotype for lysine relative to its auxotrophic phenotype for methionine depended upon its level of lipophilicity-dependent accumulation inside the mitochondria. We conclude that localization within the cell is an important factor in biological efficacy in addition to the degree of catalytic activity, and we discuss possible explanations for this effect.

Authors
Li, AM; Martins, J; Tovmasyan, A; Valentine, JS; Batinic-Haberle, I; Spasojevic, I; Gralla, EB
MLA Citation
Li, AM, Martins, J, Tovmasyan, A, Valentine, JS, Batinic-Haberle, I, Spasojevic, I, and Gralla, EB. "Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae." Redox biology 3 (January 2014): 1-6.
PMID
25462059
Source
epmc
Published In
Redox Biology
Volume
3
Publish Date
2014
Start Page
1
End Page
6
DOI
10.1016/j.redox.2014.09.003

Extracellular iron diminishes anticancer effects of vitamin C: an in vitro study.

In vitro studies have shown that hydrogen peroxide (H2O2) produced by high-concentration ascorbate and cell culture medium iron efficiently kills cancer cells. This provided the rationale for clinical trials of high-dose intravenous ascorbate-based treatment for cancer. A drawback in all the in vitro studies was their failure to take into account the in vivo concentration of iron to supplement cell culture media which are characterized by low iron content. Here we showed, using two prostate cancer cell lines (LNCaP and PC-3) and primary astrocytes, that the anticancer/cytotoxic effects of ascorbate are completely abolished by iron at physiological concentrations in cell culture medium and human plasma. A detailed examination of mechanisms showed that iron at physiological concentrations promotes both production and decomposition of H2O2. The latter is mediated by Fenton reaction and prevents H2O2 accumulation. The hydroxyl radical, which is produced in the Fenton reaction, is buffered by extracellular proteins, and could not affect intracellular targets like H2O2. These findings show that anticancer effects of ascorbate have been significantly overestimated in previous in vitro studies, and that common cell culture media might be unsuitable for redox research.

Authors
Mojić, M; Bogdanović Pristov, J; Maksimović-Ivanić, D; Jones, DR; Stanić, M; Mijatović, S; Spasojević, I
MLA Citation
Mojić, M, Bogdanović Pristov, J, Maksimović-Ivanić, D, Jones, DR, Stanić, M, Mijatović, S, and Spasojević, I. "Extracellular iron diminishes anticancer effects of vitamin C: an in vitro study." Scientific Reports 4 (January 2014): 5955-.
PMID
25092529
Source
epmc
Published In
Scientific Reports
Volume
4
Publish Date
2014
Start Page
5955
DOI
10.1038/srep05955

Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae

Authors
Li, AM; Martins, J; Tovmasyan, A; Valentine, JS; Batinic-Haberle, I; Spasojevic, I; Gralla, EB
MLA Citation
Li, AM, Martins, J, Tovmasyan, A, Valentine, JS, Batinic-Haberle, I, Spasojevic, I, and Gralla, EB. "Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae." REDOX BIOLOGY 3 (2014): 1-6.
Source
wos-lite
Published In
Redox Biology
Volume
3
Publish Date
2014
Start Page
1
End Page
6
DOI
10.1016/j.redox.2014.0.003

Multiple sclerosis: molecular mechanisms and therapeutic opportunities.

The pathophysiology of multiple sclerosis (MS) involves several components: redox, inflammatory/autoimmune, vascular, and neurodegenerative. All of them are supported by the intertwined lines of evidence, and none of them should be written off. However, the exact mechanisms of MS initiation, its development, and progression are still elusive, despite the impressive pace by which the data on MS are accumulating. In this review, we will try to integrate the current facts and concepts, focusing on the role of redox changes and various reactive species in MS. Knowing the schedule of initial changes in pathogenic factors and the key turning points, as well as understanding the redox processes involved in MS pathogenesis is the way to enable MS prevention, early treatment, and the development of therapies that target specific pathophysiological components of the heterogeneous mechanisms of MS, which could alleviate the symptoms and hopefully stop MS. Pertinent to this, we will outline (i) redox processes involved in MS initiation; (ii) the role of reactive species in inflammation; (iii) prooxidative changes responsible for neurodegeneration; and (iv) the potential of antioxidative therapy.

Authors
Miljković, D; Spasojević, I
MLA Citation
Miljković, D, and Spasojević, I. "Multiple sclerosis: molecular mechanisms and therapeutic opportunities." Antioxidants & redox signaling 19.18 (December 2013): 2286-2334. (Review)
PMID
23473637
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
19
Issue
18
Publish Date
2013
Start Page
2286
End Page
2334
DOI
10.1089/ars.2012.5068

The effects of human wild-type and fals mutant L144P SOD1 on non-vascular smooth muscle contractions

Background: Mutated copper, zinc-containing superoxide dismutase (SOD1) may self-aggregate, an event that could also be an initial cause of motor neuron malfunction leading to disease onset. The effects of human mutated SOD1 pro- tein from the blood of familial amyotrophic lateral sclerosis (FALS) patients bearing Leu144Phe (L144F) mutation were compared to wild-type (WT) human SOD1 derived from healthy examinees, for enzymatic activity and the effects on isometric contractions of non-vascular smooth muscle. Methods: We isolated WT and L144F SOD1 enzymes from eight patients with FALS, L144F mutation in exon 5 and eight healthy controls. We then investigated SOD1 activities in the obtained samples by the adrenaline method and pro- filed them electrophoretically. Finally, we applied WT and L144F SOD1 on the isolated rat uterus. Results: L144F SOD1 showed lower superoxide-dismutating activity compared to WT human SOD1. We found that, in contrast to WT human SOD1, mutated L144F does not induce smooth muscle relaxation. Conclusions: Our data suggest that the lack of relaxation of muscle tonus in the presence of mutated SOD1 may have pathogenic feedback effects in FALS.

Authors
Nikolić-Kokić, A; Oreščanin-Dušić, Z; Slavić, M; Spasojević, I; Stević, Z; Spasić, M; Blagojević, D
MLA Citation
Nikolić-Kokić, A, Oreščanin-Dušić, Z, Slavić, M, Spasojević, I, Stević, Z, Spasić, M, and Blagojević, D. "The effects of human wild-type and fals mutant L144P SOD1 on non-vascular smooth muscle contractions." Journal of Medical Biochemistry 32.4 (October 1, 2013): 375-379.
Source
scopus
Published In
Journal of Medical Biochemistry
Volume
32
Issue
4
Publish Date
2013
Start Page
375
End Page
379
DOI
10.2478/jomb-2013-0032

UV-irradiation provokes generation of superoxide on cell wall polygalacturonic acid.

We examined the redox effects of UV irradiation on cell wall isolates from Pisum sativum leaves, and polygalacturonic and galacturonic acid, in the presence of hydrogen peroxide. For this purpose, electron paramagnetic resonance spectroscopy and two spin-traps (DEPMPO and BMPO), capable of differentiating between various free radicals, were applied. Systems were exposed to UV-B (maximum emission at 312 nm) and UV-A (352 nm) for 10 min (6 J m(-2) s(-1)). Cell wall isolates exposed to UV in the presence of hydrogen peroxide, produced hydroxyl radical, carbon dioxide radical and superoxide. The production of superoxide was observed for cell wall isolates, polygalacturonic acid (in the presence and in the absence of calcium) and galacturonic acid, and it was diminished upon superoxide dismutase supplementation. The production is at least partially based on the reaction of hydroxyl radicals with (poly)galacturonic acid having carbon dioxide radicals as a products. Acting as a strong reducing agent, carbon dioxide radical reacts with molecular oxygen to produce superoxide. The results presented here shed a new light on: (1) the redox-modulating role of cell wall; (2) the production of superoxide in the extracellular compartment; (3) the mechanisms involved in translating UV stress into molecular signaling and (4) some other UV-related phenomena in plants, such as CO(2) emission.

Authors
Pristov, JB; Jovanović, SV; Mitrović, A; Spasojević, I
MLA Citation
Pristov, JB, Jovanović, SV, Mitrović, A, and Spasojević, I. "UV-irradiation provokes generation of superoxide on cell wall polygalacturonic acid." Physiologia plantarum 148.4 (August 2013): 574-581.
PMID
23163764
Source
epmc
Published In
Physiologia Plantarum
Volume
148
Issue
4
Publish Date
2013
Start Page
574
End Page
581
DOI
10.1111/ppl.12001

Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology.

The different biological behavior of cationic Fe and Mn pyridylporphyrins in Escherichia coli and mouse studies prompted us to revisit and compare their chemistry. For that purpose, the series of ortho and meta isomers of Fe(III) meso-tetrakis-N-alkylpyridylporphyrins, alkyl being methyl to n-octyl, were synthesized and characterized by elemental analysis, UV/vis spectroscopy, mass spectrometry, lipophilicity, protonation equilibria of axial waters, metal-centered reduction potential, E(1/2) for M(III)P/M(II)P redox couple (M = Fe, Mn, P = porphyrin), kcat for the catalysis of O2(•-) dismutation, stability toward peroxide-driven porphyrin oxidative degradation (produced in the catalysis of ascorbate oxidation by MP), ability to affect growth of SOD-deficient E. coli, and toxicity to mice. Electron-deficiency of the metal site is modulated by the porphyrin ligand, which renders Fe(III) porphyrins ≥5 orders of magnitude more acidic than the analogous Mn(III) porphyrins, as revealed by the pKa1 of axially coordinated waters. The 5 log units difference in the acidity between the Mn and Fe sites in porphyrin translates into the predominance of tetracationic (OH)(H2O)FeP complexes relative to pentacationic (H2O)2MnP species at pH ∼7.8. This is additionally evidenced in large differences in the E(1/2) values of M(III)P/M(II)P redox couples. The presence of hydroxo ligand labilizes trans-axial water which results in higher reactivity of Fe relative to Mn center. The differences in the catalysis of O2(•-) dismutation (log kcat) between Fe and Mn porphyrins is modest, 2.5-5-fold, due to predominantly outer-sphere, with partial inner-sphere character of two reaction steps. However, the rate constant for the inner-sphere H2O2-based porphyrin oxidative degradation is 18-fold larger for (OH)(H2O)FeP than for (H2O)2MnP. The in vivo consequences of the differences between the Fe and Mn porphyrins were best demonstrated in SOD-deficient E. coli growth. On the basis of fairly similar log kcat(O2(•-)) values, a very similar effect on the growth of SOD-deficient E. coli was anticipated by both metalloporphyrins. Yet, while (H2O)2MnTE-2-PyP(5+) was fully efficacious at ≥20 μM, the Fe analogue (OH)(H2O)FeTE-2-PyP(4+) supported SOD-deficient E. coli growth at as much as 200-fold lower doses in the range of 0.1-1 μM. Moreover the pattern of SOD-deficient E. coli growth was different with Mn and Fe porphyrins. Such results suggested a different mode of action of these metalloporphyrins. Further exploration demonstrated that (1) 0.1 μM (OH)(H2O)FeTE-2-PyP(4+) provided similar growth stimulation as the 0.1 μM Fe salt, while the 20 μM Mn salt provides no protection to E. coli; and (2) 1 μM Fe porphyrin is fully degraded by 12 h in E. coli cytosol and growth medium, while Mn porphyrin is not. Stimulation of the aerobic growth of SOD-deficient E. coli by the Fe porphyrin is therefore due to iron acquisition. Our data suggest that in vivo, redox-driven degradation of Fe porphyrins resulting in Fe release plays a major role in their biological action. Possibly, iron reconstitutes enzymes bearing [4Fe-4S] clusters as active sites. Under the same experimental conditions, (OH)(H2O)FePs do not cause mouse arterial hypotension, whereas (H2O)2MnPs do, which greatly limits the application of Mn porphyrins in vivo.

Authors
Tovmasyan, A; Weitner, T; Sheng, H; Lu, M; Rajic, Z; Warner, DS; Spasojevic, I; Reboucas, JS; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Weitner, T, Sheng, H, Lu, M, Rajic, Z, Warner, DS, Spasojevic, I, Reboucas, JS, Benov, L, and Batinic-Haberle, I. "Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology." Inorg Chem 52.10 (May 20, 2013): 5677-5691.
PMID
23646875
Source
pubmed
Published In
Inorganic Chemistry
Volume
52
Issue
10
Publish Date
2013
Start Page
5677
End Page
5691
DOI
10.1021/ic3012519

Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+.

The cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP(5+) (AEOL10113, FBC-007) and MnTnHex-2-PyP(5+) have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2(•-) and ONOO(-) and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood-brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP(5+) is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP(5+), which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP(5+) and 0.5 or 2mg/kg MnTnHex-2-PyP(5+). Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP(5+) and 21% for MnTnHex-2-PyP(5+). Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP(5+) than for MnTE-2-PyP(5+) (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP(5+).

Authors
Weitner, T; Kos, I; Sheng, H; Tovmasyan, A; Reboucas, JS; Fan, P; Warner, DS; Vujaskovic, Z; Batinic-Haberle, I; Spasojevic, I
MLA Citation
Weitner, T, Kos, I, Sheng, H, Tovmasyan, A, Reboucas, JS, Fan, P, Warner, DS, Vujaskovic, Z, Batinic-Haberle, I, and Spasojevic, I. "Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+." Free Radic Biol Med 58 (May 2013): 73-80.
PMID
23328731
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
58
Publish Date
2013
Start Page
73
End Page
80
DOI
10.1016/j.freeradbiomed.2013.01.006

Membrane fluidity, invasiveness and dynamic phenotype of metastatic prostate cancer cells after treatment with soy isoflavones.

Soy isoflavones represent hopeful unconventional remedies in the therapy of prostate cancer. The aim of our study was to determine the effects of genistein and daidzein on the parameters that reflect metastatic potential, membrane fluidity, invasiveness and dynamic phenotype in Matrigel of LNCaP and PC-3 prostate cancer cells. Cell viability tests, using a wide range of concentrations of soy isoflavones (6-75 μg/ml for 72 h), were conducted to determine their IC50 concentrations. Electron paramagnetic resonance investigations of prostate cancer cell membrane fluidity were performed at IC50 concentrations of genistein and daidzein (12.5 and 25 μg/ml, respectively, for 10 min). Genistein provoked significant increases in the membrane order parameter (which is reciprocally proportional to membrane fluidity) of 0.722 ± 0.006 (LNCaP), 0.753 ± 0.010 (LNCaP + genistein), 0.723 ± 0.007 (PC-3) and 0.741 ± 0.004 (PC-3 + genistein); however, no such effects were observed for daidzein. While both genistein and daidzein reduced the proliferation of prostate cancer cells at their respective IC50 concentrations, during the 72 h of incubation only genistein provoked effects on the dynamic phenotype and decreased invasiveness. The effect was more evident in PC-3 cells compared to LNCaP cells. Our results imply that (1) invasive activity is at least partially dependent on membrane fluidity, (2) genistein may exert its antimetastatic effects by changing the mechanical properties of prostate cancer cells and (3) daidzein should be applied at higher concentrations than genistein in order to achieve pharmacological effects.

Authors
Ajdžanović, V; Mojić, M; Maksimović-Ivanić, D; Bulatović, M; Mijatović, S; Milošević, V; Spasojević, I
MLA Citation
Ajdžanović, V, Mojić, M, Maksimović-Ivanić, D, Bulatović, M, Mijatović, S, Milošević, V, and Spasojević, I. "Membrane fluidity, invasiveness and dynamic phenotype of metastatic prostate cancer cells after treatment with soy isoflavones." The Journal of membrane biology 246.4 (April 2013): 307-314.
PMID
23417033
Source
epmc
Published In
The Journal of Membrane Biology
Volume
246
Issue
4
Publish Date
2013
Start Page
307
End Page
314
DOI
10.1007/s00232-013-9531-1

Converting low dose radiation to redox signaling.

In contrast to the damaging effects of high doses, low dose radiation (UV, gamma) has been reported to provoke constructive changes in plants. However, the mechanisms by which plants recognize and respond to low dose radiation are not understood. We have shown recently that polygalacturonic acid, cell wall polysaccharide, converts the highly reactive product of radiation - hydroxyl radical into superoxide which may be further dismutated to hydrogen peroxide. Superoxide has been proposed to act as a signaling molecule, while hydrogen peroxide is known to be the key species in redox signaling cascades which are involved in the regulation of various physiological processes. Hence we propose that polygalacturonic acid may operate as radiation-signaling convertor. The outlined principles of radiation-sensing could also be valid for mammalian cells, with some other molecules mediating the conversion.

Authors
Pristov, JB; Spasić, M; Spasojević, I
MLA Citation
Pristov, JB, Spasić, M, and Spasojević, I. "Converting low dose radiation to redox signaling." Plant signaling & behavior 8.2 (February 2013): e23151-.
PMID
23299433
Source
epmc
Published In
Plant signaling & behavior
Volume
8
Issue
2
Publish Date
2013
Start Page
e23151
DOI
10.4161/psb.23151

Differences in direct pharmacologic effects and antioxidative properties of mature breast milk and infant formulas.

OBJECTIVE: Early-onset and exclusive breast-feeding provides a significant health benefit to infants compared with infant formulas. The aim of this study was to compare mature breast milk with standard infant formulas by examining their effects on non-vascular smooth muscle contraction and their antioxidative properties. METHODS: The pharmacologic effects of breast milk and formulas were examined using a model system of the rat uterine smooth muscle contraction. Electron paramagnetic resonance spin-trapping spectroscopy was used to compare the antioxidative capacities of breast milk (obtained in the ninth week of lactation) with commercial infant formulas against hydroxyl radical production in the Fenton reaction. The activities of superoxide dismutase, glutathione peroxidase, and the sulfhydryl group were determined in the breast milk and infant formulas. RESULTS: In contrast to the infant formulas, breast milk exerted a relaxing effect on isolated non-vascular smooth muscle. In general, breast milk showed higher antioxidative activity compared with the infant formulas. In all samples, the generation of hydroxyl radicals led to the formation of carbon-centered and ascorbyl radicals. CONCLUSIONS: Human milk exerts direct pharmacologic relaxation effects and provides better antioxidant protection compared with infant formulas because of the presence of specific enzymatic components, such as human superoxide dismutase. We propose that these effects should be advantageous to an infant's gastrointestinal tract by supporting the normal work of the smooth musculature and maintaining redox homeostasis and may represent one of the mechanisms by which breast-feeding benefits health.

Authors
Lugonja, N; Spasić, SD; Laugier, O; Nikolić-Kokić, A; Spasojević, I; Oreščanin-Dušić, Z; Vrvić, MM
MLA Citation
Lugonja, N, Spasić, SD, Laugier, O, Nikolić-Kokić, A, Spasojević, I, Oreščanin-Dušić, Z, and Vrvić, MM. "Differences in direct pharmacologic effects and antioxidative properties of mature breast milk and infant formulas." Nutrition (Burbank, Los Angeles County, Calif.) 29.2 (February 2013): 431-435.
PMID
23312765
Source
epmc
Published In
Nutrition
Volume
29
Issue
2
Publish Date
2013
Start Page
431
End Page
435
DOI
10.1016/j.nut.2012.07.018

Disruption of wild-type IDH1 suppresses D-2-hydroxyglutarate production in IDH1-mutated gliomas.

Point mutations at Arg132 of the cytoplasmic NADP(+)-dependent isocitrate dehydrogenase 1 (IDH1) occur frequently in gliomas and result in a gain of function to produce the "oncometabolite" D-2-hydroxyglutarate (D-2HG). The mutated IDH1 allele is usually associated with a wild-type IDH1 allele (heterozygous) in cancer. Here, we identify 2 gliomas that underwent loss of the wild-type IDH1 allele but retained the mutant IDH1 allele following tumor progression from World Health Organization (WHO) grade III anaplastic astrocytomas to WHO grade IV glioblastomas. Intratumoral D-2HG was 14-fold lower in the glioblastomas lacking wild-type IDH1 than in glioblastomas with heterozygous IDH1 mutations. To characterize the contribution of wild-type IDH1 to cancer cell D-2HG production, we established an IDH1-mutated astrocytoma (IMA) cell line from a WHO grade III anaplastic astrocytoma. Disruption of the wild-type IDH1 allele in IMA cells by gene targeting resulted in an 87-fold decrease in cellular D-2HG levels, showing that both wild-type and mutant IDH1 alleles are required for D-2HG production in glioma cells. Expression of wild-type IDH1 was also critical for mutant IDH1-associated D-2HG production in the colorectal cancer cell line HCT116. These insights may aid in the development of therapeutic strategies to target IDH1-mutated cancers.

Authors
Jin, G; Reitman, ZJ; Duncan, CG; Spasojevic, I; Gooden, DM; Rasheed, BA; Yang, R; Lopez, GY; He, Y; McLendon, RE; Bigner, DD; Yan, H
MLA Citation
Jin, G, Reitman, ZJ, Duncan, CG, Spasojevic, I, Gooden, DM, Rasheed, BA, Yang, R, Lopez, GY, He, Y, McLendon, RE, Bigner, DD, and Yan, H. "Disruption of wild-type IDH1 suppresses D-2-hydroxyglutarate production in IDH1-mutated gliomas." Cancer Res 73.2 (January 15, 2013): 496-501.
PMID
23204232
Source
pubmed
Published In
Cancer Research
Volume
73
Issue
2
Publish Date
2013
Start Page
496
End Page
501
DOI
10.1158/0008-5472.CAN-12-2852

Fluctuating vs. continuous exposure to H₂O₂: the effects on mitochondrial membrane potential, intracellular calcium, and NF-κB in astroglia.

The effects of H2O2 are widely studied in cell cultures and other in vitro systems. However, such investigations are performed with the assumption that H2O2 concentration is constant, which may not properly reflect in vivo settings, particularly in redox-turbulent microenvironments such as mitochondria. Here we introduced and tested a novel concept of fluctuating oxidative stress. We treated C6 astroglial cells and primary astrocytes with H2O2, using three regimes of exposure - continuous, as well as fluctuating at low or high rate, and evaluated mitochondrial membrane potential and other parameters of mitochondrial activity - respiration, reducing capacity, and superoxide production, as well as intracellular ATP, intracellular calcium, and NF-κB activation. When compared to continuous exposure, fluctuating H2O2 induced a pronounced hyperpolarization in mitochondria, whereas the activity of electron transport chain appears not to be significantly affected. H2O2 provoked a decrease of ATP level and an increase of intracellular calcium concentration, independently of the regime of treatment. However, fluctuating H2O2 induced a specific pattern of large-amplitude fluctuations of calcium concentration. An impact on NF-κB activation was observed for high rate fluctuations, whereas continuous and low rate fluctuating oxidative stress did not provoke significant effects. Presented results outline the (patho)physiological relevance of redox fluctuations.

Authors
Bajić, A; Spasić, M; Andjus, PR; Savić, D; Parabucki, A; Nikolić-Kokić, A; Spasojević, I
MLA Citation
Bajić, A, Spasić, M, Andjus, PR, Savić, D, Parabucki, A, Nikolić-Kokić, A, and Spasojević, I. "Fluctuating vs. continuous exposure to H₂O₂: the effects on mitochondrial membrane potential, intracellular calcium, and NF-κB in astroglia." PloS one 8.10 (January 2013): e76383-.
PMID
24124554
Source
epmc
Published In
PloS one
Volume
8
Issue
10
Publish Date
2013
Start Page
e76383
DOI
10.1371/journal.pone.0076383

The effect of alcohols on red blood cell mechanical properties and membrane fluidity depends on their molecular size.

The role of membrane fluidity in determining red blood cell (RBC) deformability has been suggested by a number of studies. The present investigation evaluated alterations of RBC membrane fluidity, deformability and stability in the presence of four linear alcohols (methanol, ethanol, propanol and butanol) using ektacytometry and electron paramagnetic resonance (EPR) spectroscopy. All alcohols had a biphasic effect on deformability such that it increased then decreased with increasing concentration; the critical concentration for reversal was an inverse function of molecular size. EPR results showed biphasic changes of near-surface fluidity (i.e., increase then decrease) and a decreased fluidity of the lipid core; rank order of effectiveness was butanol > propanol > ethanol > methanol, with a significant correlation between near-surface fluidity and deformability (r = 0.697; p<0.01). The presence of alcohol enhanced the impairment of RBC deformability caused by subjecting cells to 100 Pa shear stress for 300 s, with significant differences from control being observed at higher concentrations of all four alcohols. The level of hemolysis was dependent on molecular size and concentration, whereas echinocytic shape transformation (i.e., biconcave disc to crenated morphology) was observed only for ethanol and propanol. These results are in accordance with available data obtained on model membranes. They document the presence of mechanical links between RBC deformability and near-surface membrane fluidity, chain length-dependence of the ability of alcohols to alter RBC mechanical behavior, and the biphasic response of RBC deformability and near-surface membrane fluidity to increasing alcohol concentrations.

Authors
Sonmez, M; Ince, HY; Yalcin, O; Ajdžanović, V; Spasojević, I; Meiselman, HJ; Baskurt, OK
MLA Citation
Sonmez, M, Ince, HY, Yalcin, O, Ajdžanović, V, Spasojević, I, Meiselman, HJ, and Baskurt, OK. "The effect of alcohols on red blood cell mechanical properties and membrane fluidity depends on their molecular size." PloS one 8.9 (January 2013): e76579-.
PMID
24086751
Source
epmc
Published In
PloS one
Volume
8
Issue
9
Publish Date
2013
Start Page
e76579
DOI
10.1371/journal.pone.0076579

The interactions of vanadium with Phycomyces blakesleeanus mycelium: enzymatic reduction, transport and metabolic effects.

The biological and chemical basis of vanadium action and transport in fungi is relatively poorly understood. In this study we investigated the interactions of vanadium in physiologically-relevant redox states: vanadate (+5) and vanadyl (+4), with mycelium of fungus Phycomyces blakesleeanus using EPR and (31)P NMR spectroscopy and biochemical assays. We determined that P. blakesleeanus reduces V(5+) to V(4+) in the extracellular compartment by the means of cell surface enzyme with ferricyanide reductase activity, which contains molybdenum-molybdopterin as a cofactor. Both, V(5+) and V(4+) bind to cell wall. They enter the cytoplasm via phosphate transporter and cation channels, respectively, and exhibit different metabolic effects. Vanadate provokes increased biomass production, the effects being inverted to toxic at higher V(5+) concentrations. In addition, V(5+) activates the synthesis of sugar phosphates and oligophosphates. On the other hand, V(4+) exhibits toxic effects even at low concentrations. The V(4+) detoxification route involves binding to vacuolar polyphosphates. Altogether our results imply that the mechanism of interaction of vanadium with P. blakesleeanus involves three major steps: extracellular enzymatic V(5+)/V(4+) reduction, V(4+) influx, and vacuolar storage, with an additional step - V(5+) import occurring at higher vanadate concentrations.

Authors
Žižić, M; Živić, M; Spasojević, I; Bogdanović Pristov, J; Stanić, M; Cvetić-Antić, T; Zakrzewska, J
MLA Citation
Žižić, M, Živić, M, Spasojević, I, Bogdanović Pristov, J, Stanić, M, Cvetić-Antić, T, and Zakrzewska, J. "The interactions of vanadium with Phycomyces blakesleeanus mycelium: enzymatic reduction, transport and metabolic effects." Research in microbiology 164.1 (January 2013): 61-69.
PMID
22992386
Source
epmc
Published In
Research in Microbiology
Volume
164
Issue
1
Publish Date
2013
Start Page
61
End Page
69
DOI
10.1016/j.resmic.2012.08.007

Design, mechanism of action, bioavailability and therapeutic effects of mn porphyrin-based redox modulators.

Based on aqueous redox chemistry and simple in vivo models of oxidative stress, Escherichia coli and Saccharomyces cerevisiae, the cationic Mn(III) N-substituted pyridylporphyrins (MnPs) have been identified as the most potent cellular redox modulators within the porphyrin class of drugs; their efficacy in animal models of diseases that have oxidative stress in common is based on their high ability to catalytically remove superoxide, peroxynitrite, carbonate anion radical, hypochlorite, nitric oxide, lipid peroxyl and alkoxyl radicals, thus suppressing the primary oxidative event. While doing so MnPs could couple with cellular reductants and redox-active proteins. Reactive species are widely accepted as regulators of cellular transcriptional activity: minute, nanomolar levels are essential for normal cell function, while submicromolar or micromolar levels impose oxidative stress, which is evidenced in increased inflammatory and immune responses. By removing reactive species, MnPs affect redox-based cellular transcriptional activity and consequently secondary oxidative stress, and in turn inflammatory processes. The equal ability to reduce and oxidize superoxide during the dismutation process and recently accumulated results suggest that pro-oxidative actions of MnPs may also contribute to their therapeutic effects. All our data identify the superoxide dismutase-like activity, estimated by log k(cat)O2-*), as a good measure for the therapeutic efficacy of MnPs. Their accumulation in mitochondria and their ability to cross the blood-brain barrier contribute to their remarkable efficacy. We summarize herein the therapeutic effects of MnPs in cancer, central nervous system injuries, diabetes, their radioprotective action and potential for imaging. Few of the most potent modulators of cellular redox-based pathways, MnTE2-PyP5+, MnTDE-2-ImP5+, MnTnHex-2-PyP5+ and MnTnBuOE-2-PyP5+, are under preclinical and clinical development.

Authors
Tovmasyan, A; Sheng, H; Weitner, T; Arulpragasam, A; Lu, M; Warner, DS; Vujaskovic, Z; Spasojevic, I; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Sheng, H, Weitner, T, Arulpragasam, A, Lu, M, Warner, DS, Vujaskovic, Z, Spasojevic, I, and Batinic-Haberle, I. "Design, mechanism of action, bioavailability and therapeutic effects of mn porphyrin-based redox modulators." Med Princ Pract 22.2 (2013): 103-130. (Review)
PMID
23075911
Source
pubmed
Published In
Medical principles and practice : international journal of the Kuwait University, Health Science Centre
Volume
22
Issue
2
Publish Date
2013
Start Page
103
End Page
130
DOI
10.1159/000341715

Glucocorticoid excess and disturbed hemodynamics in advanced age: the extent to which soy isoflavones may be beneficial.

Advanced age is often accompanied by glucocorticoid excess which contributes to the pathogenesis of the metabolic syndrome associated with some hemodynamic disorders. Impaired central regulation of stress hormones secretion and increased glucocorticoids/adrenal androgens ratio trigger hyperglycemia, elevated blood lipids and visceral fat accumulation, associated with hypertension and increased blood viscosity, all of which represent cardiovascular morbidity factors in this age. Finding the adequate therapeutic solutions is set as an imperative in the treatment of listed symptoms. Biologically active soy isoflavones, exhibiting estrogen- and membrane-receptor agonistic/antagonistic activity, and antioxidative and tyrosine kinase/steroidogenic enzyme inhibiting effects, appear as alternative therapeutics for various ageing-related diseases. It has been shown that soy isoflavones reduce some of the listed risk factors, while affecting the hemodynamic group of cardiovascular parameters directly, as well as indirectly via endocrine perturbations. Soy isoflavones may reverse the glucocorticoids/adrenal androgens ratio, lower serum cholesterol, slow the development of atherosclerotic plaque formation, inhibit platelet aggregation, increase cardiac contractility, but they may have diverse effects on blood viscosity and may increase triglyceride levels. Herein, we present the projection of soy isoflavones-based therapy of glucocorticoid excess and disturbed hemodynamics in advanced age, concluding that although promising, it requires the impartial approach and certain precautions.

Authors
Ajdžanović, VZ; Milošević, VL; Spasojević, IB
MLA Citation
Ajdžanović, VZ, Milošević, VL, and Spasojević, IB. "Glucocorticoid excess and disturbed hemodynamics in advanced age: the extent to which soy isoflavones may be beneficial." General physiology and biophysics 31.4 (December 2012): 367-374. (Review)
PMID
23255662
Source
epmc
Published In
General Physiology and Biophysics
Volume
31
Issue
4
Publish Date
2012
Start Page
367
End Page
374
DOI
10.4149/gpb_2012_041

Ante- and postpartum redox status of blood in women with inherited thrombophilia treated with heparin.

Authors
Pristov, JB; Maglić, D; Opačić, M; Mandić, V; Miković, Z; Spasić, M; Spasojević, I
MLA Citation
Pristov, JB, Maglić, D, Opačić, M, Mandić, V, Miković, Z, Spasić, M, and Spasojević, I. "Ante- and postpartum redox status of blood in women with inherited thrombophilia treated with heparin." Thrombosis research 130.5 (November 2012): 826-829. (Letter)
PMID
22981678
Source
epmc
Published In
Thrombosis Research
Volume
130
Issue
5
Publish Date
2012
Start Page
826
End Page
829
DOI
10.1016/j.thromres.2012.08.310

Enzyme redesign guided by cancer-derived IDH1 mutations.

Mutations in an enzyme can result in a neomorphic catalytic activity in cancers. We applied cancer-associated mutations from isocitrate dehydrogenases to homologous residues in the active sites of homoisocitrate dehydrogenases to derive enzymes that catalyze the conversion of 2-oxoadipate to (R)-2-hydroxyadipate, a critical step for adipic acid production. Thus, we provide a prototypic example of how insights from cancer genome sequencing and functional studies can aid in enzyme redesign.

Authors
Reitman, ZJ; Choi, BD; Spasojevic, I; Bigner, DD; Sampson, JH; Yan, H
MLA Citation
Reitman, ZJ, Choi, BD, Spasojevic, I, Bigner, DD, Sampson, JH, and Yan, H. "Enzyme redesign guided by cancer-derived IDH1 mutations." Nat Chem Biol 8.11 (November 2012): 887-889.
PMID
23001033
Source
pubmed
Published In
Nature Chemical Biology
Volume
8
Issue
11
Publish Date
2012
Start Page
887
End Page
889
DOI
10.1038/nchembio.1065

Mini test dose of intravenous busulfan (busulfex(®)) in allogeneic non-myeloablative stem cell transplantation, followed by liquid chromatography tandem-mass spectrometry.

Authors
Spasojevic, I; da Costa, LRS; Horwitz, ME; Long, GD; Sullivan, KM; Chute, JP; Gasparetto, C; Morris, A; Chao, NJ; Rizzieri, DA
MLA Citation
Spasojevic, I, da Costa, LRS, Horwitz, ME, Long, GD, Sullivan, KM, Chute, JP, Gasparetto, C, Morris, A, Chao, NJ, and Rizzieri, DA. "Mini test dose of intravenous busulfan (busulfex(®)) in allogeneic non-myeloablative stem cell transplantation, followed by liquid chromatography tandem-mass spectrometry." Cancer Invest 30.9 (November 2012): 679-682.
PMID
23020519
Source
pubmed
Published In
Cancer Investigation (Informa)
Volume
30
Issue
9
Publish Date
2012
Start Page
679
End Page
682
DOI
10.3109/07357907.2012.726386

Urinary biomarkers of oxidative status.

Oxidative damage produced by reactive oxygen species (ROS) has been implicated in the etiology and pathology of many health conditions, including a large number of chronic diseases. Urinary biomarkers of oxidative status present a great opportunity to study redox balance in human populations. With urinary biomarkers, specimen collection is non-invasive and the organic/metal content is low, which minimizes the artifactual formation of oxidative damage to molecules in specimens. Also, urinary levels of the biomarkers present intergraded indices of redox balance over a longer period of time compared to blood levels. This review summarizes the criteria for evaluation of biomarkers applicable to epidemiological studies and evaluation of several classes of biomarkers that are formed non-enzymatically: oxidative damage to lipids, proteins, DNA, and allantoin, an oxidative product of uric acid. The review considers formation, metabolism, and exertion of each biomarker, available data on validation in animal and clinical models of oxidative stress, analytical approaches, and their intra- and inter-individual variation. The recommended biomarkers for monitoring oxidative status over time are F₂-isoprostanes and 8-oxodG. For inter-individual comparisons, F₂-isoprostanes are recommended, whereas urinary 8-oxodG levels may be confounded by differences in the DNA repair capacity. Promising urinary biomarkers include allantoin, acrolein-lysine, and dityrosine.

Authors
Il'yasova, D; Scarbrough, P; Spasojevic, I
MLA Citation
Il'yasova, D, Scarbrough, P, and Spasojevic, I. "Urinary biomarkers of oxidative status." Clin Chim Acta 413.19-20 (October 9, 2012): 1446-1453. (Review)
PMID
22683781
Source
pubmed
Published In
Clinica Chimica Acta
Volume
413
Issue
19-20
Publish Date
2012
Start Page
1446
End Page
1453
DOI
10.1016/j.cca.2012.06.012

Endogenous production of extracellular adenosine by trabecular meshwork cells: potential role in outflow regulation.

PURPOSE: To investigate the mechanisms for endogenous production of extracellular adenosine in trabecular meshwork (TM) cells and evaluate its physiological relevance to the regulation of aqueous humor outflow facility. METHODS: Extra-cellular levels of adenosine monophosphate (AMP) and adenosine in porcine trabecular meshwork (PTM) cells treated with adenosine triphosphate (ATP), AMP, cAMP or forskolin with or without specific inhibitors of phosphodiesterases (IBMX) and CD73 (AMPCP) were determined by high-pressure liquid chromatography fluorometry. Extracellular adenosine was also evaluated in cell cultures subjected to cyclic mechanical stress (CMS) (20% stretching; 1 Hz) and after disruption of lipid rafts with methyl-β-cyclodextrin. Expression of CD39 and CD73 in porcine TM cells and tissue were examined by Q-PCR and Western blot. The effect of inhibition of CD73 on outflow facility was evaluated in perfused living mouse eyes. RESULTS: PTM cells generated extracellular adenosine from extracellular ATP and AMP but not from extracellular cAMP. Increased intracellular cAMP mediated by forskolin led to a significant increase in extracellular adenosine production that was not prevented by IBMX. Inhibition of CD73 resulted, in all cases, in a significant decrease in extracellular adenosine. CMS induced a significant activation of extracellular adenosine production. Inhibition of CD73 activity with AMPCP in living mouse eyes resulted in a significant decrease in outflow facility. CONCLUSIONS: These results support the concept that the extracellular adenosine pathway might play an important role in the homeostatic regulation of outflow resistance in the TM, and suggest a novel mechanism by which pathologic alteration of the TM, such as increased tissue rigidity, could lead to abnormal elevation of IOP in glaucoma.

Authors
Wu, J; Li, G; Luna, C; Spasojevic, I; Epstein, DL; Gonzalez, P
MLA Citation
Wu, J, Li, G, Luna, C, Spasojevic, I, Epstein, DL, and Gonzalez, P. "Endogenous production of extracellular adenosine by trabecular meshwork cells: potential role in outflow regulation. (Published online)" Invest Ophthalmol Vis Sci 53.11 (October 1, 2012): 7142-7148.
PMID
22997289
Source
pubmed
Published In
Investigative Ophthalmology and Visual Science
Volume
53
Issue
11
Publish Date
2012
Start Page
7142
End Page
7148
DOI
10.1167/iovs.12-9968

Racial differences in urinary F2-isoprostane levels and the cross-sectional association with BMI.

Levels of four urinary F(2)-isoprostanes (F(2)-IsoPs) were examined in a large sample of the Insulin Resistance Atherosclerosis Study (IRAS) multiethnic cohort: 237 African Americans (AAs), 342 non-Hispanic whites (NHWs), and 275 Hispanic whites (HWs). F(2)-IsoP isomers - iPF2a-III, 2,3-dinor-iPF2a-III, iPF2a-VI, and 8,12-iso-iPF2a-VI - were measured in 854 urine samples using liquid chromatography with tandem mass spectrometry detection. In AAs, levels of all four F(2)-IsoPs were lower compared with NHWs and HWs (P values <0.05). When stratified by BMI, this gap was not observed among participants with normal BMI but appeared among overweight participants and increased among obese participants. Examining the slopes of the associations between BMI and F(2)-IsoPs showed no association between these variables among AAs (P values >0.2), and positive associations among whites (P values <0.05). Taking into account that positive cross-sectional associations between systemic F(2)-IsoP levels and BMI have been consistently demonstrated in many study populations, the lack of such an association among AAs reveals a new facet of racial/ethnic differences in obesity-related risk profiles.

Authors
Il'yasova, D; Wang, F; Spasojevic, I; Base, K; D'Agostino, RB; Wagenknecht, LE
MLA Citation
Il'yasova, D, Wang, F, Spasojevic, I, Base, K, D'Agostino, RB, and Wagenknecht, LE. "Racial differences in urinary F2-isoprostane levels and the cross-sectional association with BMI." Obesity (Silver Spring) 20.10 (October 2012): 2147-2150.
PMID
22836686
Source
pubmed
Published In
Obesity
Volume
20
Issue
10
Publish Date
2012
Start Page
2147
End Page
2150
DOI
10.1038/oby.2012.170

Urinary F2-isoprostanes, obesity, and weight gain in the IRAS cohort.

Obesity has been associated with increased F(2)-isoprostane (F(2)-IsoP) levels cross-sectionally. However, the prospective association may be inverse, based on our earlier finding that elevated urinary F(2)-IsoP levels predict lower risk of diabetes. This earlier finding led us to hypothesize that urinary F(2)-IsoPs reflect the intensity of oxidative metabolism and as such predict lower risk of both diabetes and weight gain. We examined cross-sectional relationships with obesity and prospective relationships with weight gain using the data from 299 participants of the Insulin Resistance Atherosclerosis Study (IRAS), all of whom were free of diabetes at baseline. Four urinary F(2)-IsoPs were assayed in stored baseline urine samples using liquid chromatography with tandem mass spectrometry: iPF(2α)-III, 2,3-dinor-iPF(2α)-III, iPF(2α)-VI, and 8,12-iso-iPF(2α)-VI (F(2)-IsoP 1-4, respectively). Baseline F(2)-IsoPs were positively associated with baseline measures of obesity; the strongest associations were found with two F(2)-IsoPs: odds ratios (95% confidence intervals) for overall and abdominal obesity were 1.74 (1.26-2.40) and 1.63 (1.18-2.24) for F(2)-IsoP2 and 1.47 (1.12-1.94) and 1.64 (1.22-2.20) for F(2)-IsoP4. F(2)-IsoP2 showed the strongest and significant inverse association with weight gain during the 5-year follow-up period: increase in F(2)-IsoP2 equal to 1 s.d. was associated with 0.90 kg lower weight gain (P = 0.02) and the odds ratios for relative (≥5%) and absolute (≥5 kg) weight gain were 0.67 (0.47-0.96) and 0.57 (0.37-0.87), respectively. The other three F(2)-IsoPs were consistently inversely associated with weight gain, although not significantly, suggesting that different F(2)-IsoPs vary in their ability to detect the association with weight gain.

Authors
Il'yasova, D; Wang, F; Spasojevic, I; Base, K; D'Agostino, RB; Wagenknecht, LE
MLA Citation
Il'yasova, D, Wang, F, Spasojevic, I, Base, K, D'Agostino, RB, and Wagenknecht, LE. "Urinary F2-isoprostanes, obesity, and weight gain in the IRAS cohort." Obesity (Silver Spring) 20.9 (September 2012): 1915-1921.
PMID
21959342
Source
pubmed
Published In
Obesity
Volume
20
Issue
9
Publish Date
2012
Start Page
1915
End Page
1921
DOI
10.1038/oby.2011.292

Systemic markers of oxidative status and colorectal adenomatous polyps.

PURPOSE: Oxidative damage has been implicated in carcinogenesis. We hypothesized that elevated systemic oxidative status would be associated with later occurrence of colorectal adenomatous polyps, a precursor of colorectal cancer. METHODS: We examined the prospective association between four systemic markers of oxidative status and colorectal adenomatous polyps within a nondiabetic subcohort of the Insulin Resistance Atherosclerosis Study (n = 425). Urine samples were collected from 1992 to 1994 and colorectal adenomas prevalence were assessed in 2002 to 2004. Oxidative status markers were assessed, which included four F(2)-isoprostanes (F(2)-IsoPs) from the classes III and IV: iPF2α-III, 2,3-dinor-iPF2α-III (a metabolite of iPF2α-III), iPF2α-VI, and 8,12-iso-iPF2α-VI. All biomarkers were quantified using liquid chromatography-tandem mass spectrometry. Prospective associations were assessed using multivariate logistic regression analysis. RESULTS: The adjusted odds ratio (OR) (95% confidence interval [CI]) for occurrence of colorectal adenomatous polyps and scaled to 1 SD of F(2)-IsoP distribution were 1.16 (95% CI, 0.88-1.50), 0.88 (95% CI, 0.63-1.17), 1.04 (95% CI, 0.80-1.34), and 1.16 (95% CI, 0.90-1.48) for iPF2α-III, iPF2α-VI, 8,12-iso-iPF2α-VI, and 2,3-dinor-iPF2α-III, respectively. CONCLUSIONS: The lack of association between F(2)-IsoPs and adenomatous polyps does not support the hypothesis that elevated oxidative status is associated with colorectal adenomatous polyp occurrence during a 10-year period of follow-up.

Authors
Siamakpour-Reihani, S; Scarbrough, PM; Wang, F; Spasojevic, I; Base, K; Sedjo, R; D'Agostino, RB; Il'yasova, D
MLA Citation
Siamakpour-Reihani, S, Scarbrough, PM, Wang, F, Spasojevic, I, Base, K, Sedjo, R, D'Agostino, RB, and Il'yasova, D. "Systemic markers of oxidative status and colorectal adenomatous polyps." Ann Epidemiol 22.8 (August 2012): 587-591.
PMID
22695388
Source
pubmed
Published In
Annals of Epidemiology
Volume
22
Issue
8
Publish Date
2012
Start Page
587
End Page
591
DOI
10.1016/j.annepidem.2012.05.001

Mutant IDH1 is required for IDH1 mutated tumor cell growth.

Frequent somatic hotspot mutations in isocitrate dehydrogenase 1 (IDH1) have been identified in gliomas, acute myeloid leukemias, chondrosarcomas, and other cancers, providing a likely avenue for targeted cancer therapy. However, whether mutant IDH1 protein is required for maintaining IDH1 mutated tumor cell growth remains unknown. Here, using a genetically engineered inducible system, we report that selective suppression of endogenous mutant IDH1 expression in HT1080, a fibrosarcoma cell line with a native IDH1(R132C) heterozygous mutation, significantly inhibits cell proliferation and decreases clonogenic potential. Our findings offer insights into changes that may contribute to the inhibition of cell proliferation and offer a strong preclinical rationale for utilizing mutant IDH1 as a valid therapeutic target.

Authors
Jin, G; Pirozzi, CJ; Chen, LH; Lopez, GY; Duncan, CG; Feng, J; Spasojevic, I; Bigner, DD; He, Y; Yan, H
MLA Citation
Jin, G, Pirozzi, CJ, Chen, LH, Lopez, GY, Duncan, CG, Feng, J, Spasojevic, I, Bigner, DD, He, Y, and Yan, H. "Mutant IDH1 is required for IDH1 mutated tumor cell growth." Oncotarget 3.8 (August 2012): 774-782.
PMID
22885298
Source
pubmed
Published In
Oncotarget
Volume
3
Issue
8
Publish Date
2012
Start Page
774
End Page
782
DOI
10.18632/oncotarget.577

The reaction of methionine with hydroxyl radical: reactive intermediates and methanethiol production.

The mechanisms of reaction of methionine with hydroxyl radical are not fully understood. Here, we unequivocally show using electron paramagnetic resonance spin-trapping spectroscopy and GC-FID and GC-MS, the presence of specific carbon-, nitrogen- and sulfur-centered radicals as intermediates of this reaction, as well as the liberation of methanethiol as a gaseous end product. Taking into account the many roles that methionine has in eco- and biosystems, our results may elucidate redox chemistry of this amino acid and processes that methionine is involved in.

Authors
Spasojević, I; Bogdanović Pristov, J; Vujisić, L; Spasić, M
MLA Citation
Spasojević, I, Bogdanović Pristov, J, Vujisić, L, and Spasić, M. "The reaction of methionine with hydroxyl radical: reactive intermediates and methanethiol production." Amino acids 42.6 (June 2012): 2439-2445.
PMID
21830117
Source
epmc
Published In
Amino Acids
Volume
42
Issue
6
Publish Date
2012
Start Page
2439
End Page
2445
DOI
10.1007/s00726-011-1049-1

Inappropriately chelated iron in the cerebrospinal fluid of amyotrophic lateral sclerosis patients.

ALS is characterized by oxidative damage in the brain and cerebrospinal fluid, which is exerted by pro-oxidative activity of iron. Such activity of iron can be drastically increased in the presence of inappropriate iron ligands that catalyze redox cycling of iron, thereby promoting hydroxyl radical generation. The aim of our study was to determine the relative level of inappropriate iron ligands in the cerebrospinal fluid of ALS patients. To determine the levels of inappropriate iron ligands and redox activity of iron in cerebrospinal fluid (10 samples from ALS patients and 10 controls), we applied electron paramagnetic resonance spectroscopy. We have shown that cerebrospinal fluid of ALS patients comprises two-fold increased level of inappropriate iron ligands, proportionally increasing iron redox activity and hydroxyl radical production compared to controls. In conclusion, our results strongly support the pro-oxidative/detrimental role of inappropriately chelated iron in ALS pathophysiology. The identification of biomolecules that form such iron complexes and their therapeutic targeting may represent the future of ALS treatment.

Authors
Ignjatović, A; Stević, Z; Lavrnić, D; Nikolić-Kokić, A; Blagojević, D; Spasić, M; Spasojević, I
MLA Citation
Ignjatović, A, Stević, Z, Lavrnić, D, Nikolić-Kokić, A, Blagojević, D, Spasić, M, and Spasojević, I. "Inappropriately chelated iron in the cerebrospinal fluid of amyotrophic lateral sclerosis patients." Amyotrophic lateral sclerosis : official publication of the World Federation of Neurology Research Group on Motor Neuron Diseases 13.4 (June 2012): 357-362.
PMID
22424123
Source
epmc
Published In
Amyotrophic Lateral Sclerosis
Volume
13
Issue
4
Publish Date
2012
Start Page
357
End Page
362
DOI
10.3109/17482968.2012.665929

A new SOD mimic, Mn(III) ortho N-butoxyethylpyridylporphyrin, combines superb potency and lipophilicity with low toxicity.

The Mn porphyrins of k(cat)(O(2)(.-)) as high as that of a superoxide dismutase enzyme and of optimized lipophilicity have already been synthesized. Their exceptional in vivo potency is at least in part due to their ability to mimic the site and location of mitochondrial superoxide dismutase, MnSOD. MnTnHex-2-PyP(5+) is the most studied among lipophilic Mn porphyrins. It is of remarkable efficacy in animal models of oxidative stress injuries and particularly in central nervous system diseases. However, when used at high single and multiple doses it becomes toxic. The toxicity of MnTnHex-2-PyP(5+) has been in part attributed to its micellar properties, i.e., the presence of polar cationic nitrogens and hydrophobic alkyl chains. The replacement of a CH(2) group by an oxygen atom in each of the four alkyl chains was meant to disrupt the porphyrin micellar character. When such modification occurs at the end of long alkyl chains, the oxygens become heavily solvated, which leads to a significant drop in the lipophilicity of porphyrin. However, when the oxygen atoms are buried deeper within the long heptyl chains, their excessive solvation is precluded and the lipophilicity preserved. The presence of oxygens and the high lipophilicity bestow the exceptional chemical and physical properties to Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, MnTnBuOE-2-PyP(5+). The high SOD-like activity is preserved and even enhanced: log k(cat)(O(2)(.-))=7.83 vs 7.48 and 7.65 for MnTnHex-2-PyP(5+) and MnTnHep-2-PyP(5+), respectively. MnTnBuOE-2-PyP(5+) was tested in an O(2)(.-) -specific in vivo assay, aerobic growth of SOD-deficient yeast, Saccharomyces cerevisiae, where it was fully protective in the range of 5-30 μM. MnTnHep-2-PyP(5+) was already toxic at 5 μM, and MnTnHex-2-PyP(5+) became toxic at 30 μM. In a mouse toxicity study, MnTnBuOE-2-PyP(5+) was several-fold less toxic than either MnTnHex-2-PyP(5+) or MnTnHep-2-PyP(5+).

Authors
Rajic, Z; Tovmasyan, A; Spasojevic, I; Sheng, H; Lu, M; Li, AM; Gralla, EB; Warner, DS; Benov, L; Batinic-Haberle, I
MLA Citation
Rajic, Z, Tovmasyan, A, Spasojevic, I, Sheng, H, Lu, M, Li, AM, Gralla, EB, Warner, DS, Benov, L, and Batinic-Haberle, I. "A new SOD mimic, Mn(III) ortho N-butoxyethylpyridylporphyrin, combines superb potency and lipophilicity with low toxicity." Free Radic Biol Med 52.9 (May 1, 2012): 1828-1834.
PMID
22336516
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
52
Issue
9
Publish Date
2012
Start Page
1828
End Page
1834
DOI
10.1016/j.freeradbiomed.2012.02.006

Manganese superoxide dismutase, MnSOD and its mimics.

Increased understanding of the role of mitochondria under physiological and pathological conditions parallels increased exploration of synthetic and natural compounds able to mimic MnSOD - endogenous mitochondrial antioxidant defense essential for the existence of virtually all aerobic organisms from bacteria to humans. This review describes most successful mitochondrially-targeted redox-active compounds, Mn porphyrins and MitoQ(10) in detail, and briefly addresses several other compounds that are either catalysts of O(2)(-) dismutation, or its non-catalytic scavengers, and that reportedly attenuate mitochondrial dysfunction. While not a true catalyst (SOD mimic) of O(2)(-) dismutation, MitoQ(10) oxidizes O(2)(-) to O(2) with a high rate constant. In vivo it is readily reduced to quinol, MitoQH(2), which in turn reduces ONOO(-) to NO(2), producing semiquinone radical that subsequently dismutes to MitoQ(10) and MitoQH(2), completing the "catalytic" cycle. In MitoQ(10), the redox-active unit was coupled via 10-carbon atom alkyl chain to monocationic triphenylphosphonium ion in order to reach the mitochondria. Mn porphyrin-based SOD mimics, however, were designed so that their multiple cationic charge and alkyl chains determine both their remarkable SOD potency and carry them into the mitochondria. Several animal efficacy studies such as skin carcinogenesis and UVB-mediated mtDNA damage, and subcellular distribution studies of Saccharomyces cerevisiae and mouse heart provided unambiguous evidence that Mn porphyrins mimic the site and action of MnSOD, which in turn contributes to their efficacy in numerous in vitro and in vivo models of oxidative stress. Within a class of Mn porphyrins, lipophilic analogs are particularly effective for treating central nervous system injuries where mitochondria play key role. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Authors
Miriyala, S; Spasojevic, I; Tovmasyan, A; Salvemini, D; Vujaskovic, Z; St Clair, D; Batinic-Haberle, I
MLA Citation
Miriyala, S, Spasojevic, I, Tovmasyan, A, Salvemini, D, Vujaskovic, Z, St Clair, D, and Batinic-Haberle, I. "Manganese superoxide dismutase, MnSOD and its mimics." Biochim Biophys Acta 1822.5 (May 2012): 794-814. (Review)
PMID
22198225
Source
pubmed
Published In
Biochimica et Biophysica Acta: international journal of biochemistry and biophysics
Volume
1822
Issue
5
Publish Date
2012
Start Page
794
End Page
814
DOI
10.1016/j.bbadis.2011.12.002

In vitro investigation of the antihypertensive effect of the moss rhodobryum ontariense (kindb.) (kindb.)

The ability to modulate erythrocyte membrane fluidity, the capacity to release nitric oxide and the ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] cation scavenging activity including the total phenolic content screening of the moss Rhodobryum ontariense tea, a traditional Chinese herbal medicine for hypertension and a wide range of cardiovascular diseases, were conducted in vitro in this study. This medicinal tea did not affect human erythrocyte membrane fluidity, did not contain reservoir of nitric oxide to be eliminated in blood and it showed low ABTS cation scavenging activity including meager content of total phenolic compounds. The obtained results excluded in a great extent some possible mechanisms of action of R. ontariense tea in relation to highlighted medical conditions.

Authors
Pejin, B; Kien-Thai, Y; Bogdanovic-Pristov, J; Pejin, I; Spasojevic, I
MLA Citation
Pejin, B, Kien-Thai, Y, Bogdanovic-Pristov, J, Pejin, I, and Spasojevic, I. "In vitro investigation of the antihypertensive effect of the moss rhodobryum ontariense (kindb.) (kindb.)." Digest Journal of Nanomaterials and Biostructures 7.1 (March 16, 2012): 353-359.
Source
scopus
Published In
Digest Journal of Nanomaterials and Biostructures
Volume
7
Issue
1
Publish Date
2012
Start Page
353
End Page
359

Vitex Agnus-Castus L. Essential Oil Increases Human Erythrocyte Membrane Fluidity

Authors
Ajdžanović, V; Spasojević, I; Pantelić, J; Šošić-Jurjević, B; Filipović, B; Milošević, V; Severs, W
MLA Citation
Ajdžanović, V, Spasojević, I, Pantelić, J, Šošić-Jurjević, B, Filipović, B, Milošević, V, and Severs, W. "Vitex Agnus-Castus L. Essential Oil Increases Human Erythrocyte Membrane Fluidity." Journal of Medical Biochemistry 31.3 (January 1, 2012).
Source
crossref
Published In
Journal of Medical Biochemistry
Volume
31
Issue
3
Publish Date
2012
DOI
10.2478/v10011-011-0055-x

Hydrogen peroxide in adaptation.

Authors
Spasojević, I; Jones, DR; Andrades, ME
MLA Citation
Spasojević, I, Jones, DR, and Andrades, ME. "Hydrogen peroxide in adaptation." Oxidative medicine and cellular longevity 2012 (January 2012): 596019-.
PMID
23326624
Source
epmc
Published In
Oxidative Medicine and Cellular Longevity
Volume
2012
Publish Date
2012
Start Page
596019
DOI
10.1155/2012/596019

Bench-to-bedside review: Neonatal sepsis-redox processes in pathogenesis.

The present review is aimed at elucidating the neonatal 'sepsis redox cycle'--the cascade of inflammatory and redox events involved in the pathogenesis of sepsis in neonates. While adult and neonatal sepses share some common features, there are some substantial differences: higher mortality rates occur in adult sepsis and worse long-term effects are evident in neonatal sepsis survivors. Such epidemiological data may be explained by the lower ability of IL6 and IL8 to activate NF-κB-regulated transcription in neonatal sepsis in comparison to TNF-α, which is involved in the mechanisms of adult sepsis. The activation of NF-κB in neonatal sepsis is further promoted by hydrogen peroxide and results in mitochondrial dysfunction and energy failure as septic neonates experience decreased O2 consumption as well as lower heat production and body temperature in comparison to healthy peers. In neonates, specific organs that are still under development are vulnerable to sepsis-provoked stress, which may lead to brain, lung, and heart injury, as well as vision and hearing impairments. In the light of the processes integrated here, it is clear that therapeutic approaches should also target specific steps in the neonatal 'sepsis redox cycle' in addition to the current therapeutic approach that is mainly focused on pathogen eradication.

Authors
Spasojević, I; Obradović, B; Spasić, S
MLA Citation
Spasojević, I, Obradović, B, and Spasić, S. "Bench-to-bedside review: Neonatal sepsis-redox processes in pathogenesis." Critical care (London, England) 16.3 (January 2012): 221-. (Review)
PMID
22574892
Source
epmc
Published In
Critical Care
Volume
16
Issue
3
Publish Date
2012
Start Page
221
DOI
10.1186/cc11183

Urinary F2-isoprostanes as a biomarker of reduced risk of type 2 diabetes.

OBJECTIVE: We have previously reported evidence of an inverse association between a urinary F(2)-isoprostane and type 2 diabetes risk in a pilot case-control study nested within the Insulin Resistance Atherosclerosis Study (IRAS). Here, we report the results from the study extended to the entire IRAS cohort. RESEARCH DESIGN AND METHODS: This prospective study included 138 incident type 2 diabetes case and 714 noncase subjects. Four F(2)-isoprostanes (iPF2α-III; 2,3-dinor-iPF2α-III; iPF2α-VI; and 8,12-iso-iPF2α-VI) were assayed in baseline urine samples using liquid chromatography-tandem mass spectrometry. RESULTS: Three F(2)-isoprostanes showed significant inverse associations with type 2 diabetes risk: the adjusted odds ratios were 0.52 (95% CI 0.39-0.67), 0.56 (0.42-0.73), 0.62 (0.48-0.79), and 0.91 (0.72-1.12) for iPF2α-III; 2,3-dinor-iPF2α-III; iPF2α-VI; and 8,12-iso-iPF2α-VI, respectively. CONCLUSIONS: Our findings indicate that urinary F(2)-isoprostanes are inversely associated with type 2 diabetes risk beyond the traditional risk factors and may be useful in identifying high-risk populations.

Authors
Il'yasova, D; Spasojevic, I; Base, K; Zhang, H; Wang, F; Young, SP; Millington, DS; D'Agostino, RB; Wagenknecht, LE
MLA Citation
Il'yasova, D, Spasojevic, I, Base, K, Zhang, H, Wang, F, Young, SP, Millington, DS, D'Agostino, RB, and Wagenknecht, LE. "Urinary F2-isoprostanes as a biomarker of reduced risk of type 2 diabetes." Diabetes Care 35.1 (January 2012): 173-174.
PMID
22100959
Source
pubmed
Published In
Diabetes Care
Volume
35
Issue
1
Publish Date
2012
Start Page
173
End Page
174
DOI
10.2337/dc11-1502

Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities.

The most efficacious Mn(III) porphyrinic (MnPs) scavengers of reactive species have positive charges close to the Mn site, whereby they afford thermodynamic and electrostatic facilitation for the reaction with negatively charged species such as O (2) (•-) and ONOO(-). Those are Mn(III) meso tetrakis(N-alkylpyridinium-2-yl)porphyrins, more specifically MnTE-2-PyP(5+) (AEOL10113) and MnTnHex-2-PyP(5+) (where alkyls are ethyl and n-hexyl, respectively), and their imidazolium analog, MnTDE-2-ImP(5+) (AEOL10150, Mn(III) meso tetrakis(N,N'-diethylimidazolium-2-yl) porphyrin). The efficacy of MnPs in vivo is determined not only by the compound antioxidant potency, but also by its bioavailability. The former is greatly affected by the lipophilicity, size, structure, and overall shape of the compound. These porphyrins have the ability to both eliminate reactive oxygen species and impact the progression of oxidative stress-dependent signaling events. This will effectively lead to the regulation of redox-dependent transcription factors and the suppression of secondary inflammatory- and oxidative stress-mediated immune responses. We have reported on the inhibition of major transcription factors HIF-1α, AP-1, SP-1, and NF-κB by Mn porphyrins. While the prevailing mechanistic view of the suppression of transcription factors activation is via antioxidative action (presumably in cytosol), the pro-oxidative action of MnPs in suppressing NF-κB activation in nucleus has been substantiated. The magnitude of the effect is dependent upon the electrostatic (porphyrin charges) and thermodynamic factors (porphyrin redox ability). The pro-oxidative action of MnPs has been suggested to contribute at least in part to the in vitro anticancer action of MnTE-2-PyP(5+) in the presence of ascorbate, and in vivo when combined with chemotherapy of lymphoma. Given the remarkable therapeutic potential of metalloporphyrins, future studies are warranted to further our understanding of in vivo action/s of Mn porphyrins, particularly with respect to their subcellular distribution.

Authors
Batinic-Haberle, I; Spasojevic, I; Tse, HM; Tovmasyan, A; Rajic, Z; St Clair, DK; Vujaskovic, Z; Dewhirst, MW; Piganelli, JD
MLA Citation
Batinic-Haberle, I, Spasojevic, I, Tse, HM, Tovmasyan, A, Rajic, Z, St Clair, DK, Vujaskovic, Z, Dewhirst, MW, and Piganelli, JD. "Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities." Amino Acids 42.1 (January 2012): 95-113. (Review)
PMID
20473774
Source
pubmed
Published In
Amino Acids
Volume
42
Issue
1
Publish Date
2012
Start Page
95
End Page
113
DOI
10.1007/s00726-010-0603-6

Erratum: Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities (Amino Acids DOI: 10.1007/s00726-010-0603-6)

Authors
Batinic-Haberle, I; Spasojevic, I; Tse, HM; Tovmasyan, A; Rajic, Z; Clair, DKS; Vujaskovic, Z; Dewhirst, MW; Piganelli, JD
MLA Citation
Batinic-Haberle, I, Spasojevic, I, Tse, HM, Tovmasyan, A, Rajic, Z, Clair, DKS, Vujaskovic, Z, Dewhirst, MW, and Piganelli, JD. "Erratum: Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities (Amino Acids DOI: 10.1007/s00726-010-0603-6)." Amino Acids 42.1 (2012): 115-116.
Source
scival
Published In
Amino Acids
Volume
42
Issue
1
Publish Date
2012
Start Page
115
End Page
116
DOI
10.1007/s00726-010-0821-y

The antioxidant, MnTE-2-PyP, prevents side-effects incurred by prostate cancer irradiation.

Prostate cancer is the most commonly diagnosed cancer, with an estimated 240,000 new cases reported annually in the United States. Due to early detection and advances in therapies, more than 90% of patients will survive 10 years post diagnosis and treatment. Radiation is a treatment option often used to treat localized disease; however, while radiation is very effective at killing tumor cells, normal tissues are damaged as well. Potential side-effects due to prostate cancer-related radiation therapy include bowel inflammation, erectile dysfunction, urethral stricture, rectal bleeding and incontinence. Currently, radiation therapy for prostate cancer does not include the administration of therapeutic agents to reduce these side effects and protect normal tissues from radiation-induced damage. In the current study, we show that the small molecular weight antioxidant, MnTE-2-PyP, protects normal tissues from radiation-induced damage in the lower abdomen in rats. Specifically, MnTE-2-PyP protected skin, prostate, and testes from radiation-induced damage. MnTE-2-PyP also protected from erectile dysfunction, a persistent problem regardless of the type of radiation techniques used because the penile neurovascular bundles lay in the peripheral zones of the prostate, where most prostate cancers reside. Based on previous studies showing that MnTE-2-PyP, in combination with radiation, further reduces subcutaneous tumor growth, we believe that MnTE-2-PyP represents an excellent radioprotectant in combination radiotherapy for cancer in general and specifically for prostate cancer.

Authors
Oberley-Deegan, RE; Steffan, JJ; Rove, KO; Pate, KM; Weaver, MW; Spasojevic, I; Frederick, B; Raben, D; Meacham, RB; Crapo, JD; Koul, HK
MLA Citation
Oberley-Deegan, RE, Steffan, JJ, Rove, KO, Pate, KM, Weaver, MW, Spasojevic, I, Frederick, B, Raben, D, Meacham, RB, Crapo, JD, and Koul, HK. "The antioxidant, MnTE-2-PyP, prevents side-effects incurred by prostate cancer irradiation." PLoS One 7.9 (2012): e44178-.
PMID
22984473
Source
pubmed
Published In
PloS one
Volume
7
Issue
9
Publish Date
2012
Start Page
e44178
DOI
10.1371/journal.pone.0044178

The effect of aprepitant and race on the pharmacokinetics of cyclophosphamide in breast cancer patients

Purpose The prodrug cyclophosphamide is metabolized by cytochrome P450(CYP)2B6 to the active metabolite, 4-hydroxycyclophosphamide (4-OH), and by CYP3A4/5 to toxic chloracetaldehyde and 2-dechloroethylcyclophosphamide (DCE). Since aprepitant is a moderate inhibitor of CYP3A4, the study was designed to determine whether its concurrent use alters the pharmacokinetics (PK) of cyclophosphamide. In addition, we sought to determine the effect of race and pharmacogenomics on cyclophosphamide PK. Methods Eighteen patients with localized breast cancer were randomized in this double-blinded cross-over study to receive aprepitant or placebo in addition to cyclophosphamide 600 mg/m 2 and doxorubicin 60 mg/m 2. Blood samples were collected for both PK analysis of cyclophosphamide and metabolites and pharmacogenomic analysis. Single nucleotide polymorphisms genotyped were CYP3A4*1B, CYP3A5*3, and CYP2B6*6. Results The geometric mean area under concentration-time curve (AUC 0-t μg/mL h) for cyclophosphamide was 282 following aprepitant and 230 following placebo (ratio 1.23; 90% CI 1.13, 1.33). 4-OH AUC 0-t (μg/mL h) was 6.80 following aprepitant and 6.96 following placebo (ratio 0.98; 90% CI 0.88, 1.08). DCE AUC 0-t (μg/mL h) was 6.76 following aprepitant and 9.37 following placebo (ratio 0.72; 90% CI 0.64, 0.81). Genotype analysis was confounded by race. Race was a significant predictor of DCE lnAUC 0-t (P = 0.0169) as African Americans had approximately a 2-fold higher DCE AUC than Caucasians. Conclusions Aprepitant altered the exposure of cyclophosphamide and DCE but not the active 4-OH metabolite, making it unlikely that aprepitant would change the clinical efficacy of cyclophosphamide. African Americans were also found to have altered PK compared with Caucasian patients. © Springer-Verlag 2012.

Authors
Walko, CM; Combest, AJ; Spasojevic, I; Yu, AYC; Bhushan, S; Hull, JH; Hoskins, J; Armstrong, D; Carey, L; Collicio, F; Dees, EC
MLA Citation
Walko, CM, Combest, AJ, Spasojevic, I, Yu, AYC, Bhushan, S, Hull, JH, Hoskins, J, Armstrong, D, Carey, L, Collicio, F, and Dees, EC. "The effect of aprepitant and race on the pharmacokinetics of cyclophosphamide in breast cancer patients." Cancer Chemotherapy and Pharmacology 69.5 (2012): 1189-1196.
PMID
22245954
Source
scival
Published In
Cancer Chemotherapy and Pharmacology
Volume
69
Issue
5
Publish Date
2012
Start Page
1189
End Page
1196
DOI
10.1007/s00280-011-1815-5

Sampling and mass spectrometric analytical methods for five antineoplastic drugs in the healthcare environment

Context. Healthcare worker exposure to antineoplastic drugs continues to be reported despite safe handling guidelines published by several groups. Sensitive sampling and analytical methods are needed so that occupational safety and health professionals may accurately assess environmental and biological exposure to these drugs in the workplace.Objective. To develop liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analytical methods for measuring five antineoplastic drugs in samples from the work environment, and to apply these methods in validating sampling methodology. A single method for quantifying several widely used agents would decrease the number of samples required for method development, lower cost, and time of analysis. Methods for measuring these drugs in workers' urine would also be useful in monitoring personal exposure levels.Results. LC-MS/MS methods were developed for individual analysis of five antineoplastic drugs in wipe and air sample media projected for use in field sampling: cyclophosphamide, ifosfamide, paclitaxel, doxorubicin, and 5-fluorouracil. Cyclophosphamide, ifosfamide, and paclitaxel were also measured simultaneously in some stages of the work. Extraction methods for air and wipe samples were developed and tested using the aforementioned analytical methods. Good recoveries from the candidate air and wipe sample media for most of the compounds, and variable recoveries for test wipe samples depending on the surface under study, were observed. Alternate LC-MS/MS methods were also developed to detect cyclophosphamide and paclitaxel in urine samples.Conclusions. The sampling and analytical methods were suitable for determining worker exposure to antineoplastics via surface and breathing zone contamination in projected surveys of healthcare settings. © The Author(s) 2010 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Authors
Pretty, JR; Connor, TH; Spasojevic, I; Kurtz, KS; McLaurin, JL; B'Hymer, C; Debord, DG
MLA Citation
Pretty, JR, Connor, TH, Spasojevic, I, Kurtz, KS, McLaurin, JL, B'Hymer, C, and Debord, DG. "Sampling and mass spectrometric analytical methods for five antineoplastic drugs in the healthcare environment." Journal of Oncology Pharmacy Practice 18.1 (2012): 23-36.
PMID
21183556
Source
scival
Published In
Journal of Oncology Pharmacy Practice
Volume
18
Issue
1
Publish Date
2012
Start Page
23
End Page
36
DOI
10.1177/1078155210389215

Cytotoxic effects of Mn(III) N-alkylpyridylporphyrins in the presence of cellular reductant, ascorbate.

Due to the ability to easily accept and donate electrons Mn(III)N-alkylpyridylporphyrins (MnPs) can dismute O(2)(·-), reduce peroxynitrite, but also generate reactive species and behave as pro-oxidants if conditions favour such action. Herein two ortho isomers, MnTE-2-PyP(5+), MnTnHex-2-PyP(5+), and a meta isomer MnTnHex-3-PyP(5+), which differ greatly with regard to their metal-centered reduction potential, E(1/2) (Mn(III)P/Mn(II)P) and lipophilicity, were explored. Employing Mn(III)P/Mn(II)P redox system for coupling with ascorbate, these MnPs catalyze ascorbate oxidation and thus peroxide production. Consequently, cancer oxidative burden may be enhanced, which in turn would suppress its growth. Cytotoxic effects on Caco-2, Hela, 4T1, HCT116 and SUM149 were studied. When combined with ascorbate, MnPs killed cancer cells via peroxide produced outside of the cell. MnTE-2-PyP(5+) was the most efficacious catalyst for peroxide production, while MnTnHex-3-PyP(5+) is most prone to oxidative degradation with H(2) , and thus the least efficacious. A 4T1 breast cancer mouse study of limited scope and success was conducted. The tumour oxidative stress was enhanced and its microvessel density reduced when mice were treated either with ascorbate or MnP/ascorbate; the trend towards tumour growth suppression was detected.

Authors
Ye, X; Fels, D; Tovmasyan, A; Aird, KM; Dedeugd, C; Allensworth, JL; Kos, I; Park, W; Spasojevic, I; Devi, GR; Dewhirst, MW; Leong, KW; Batinic-Haberle, I
MLA Citation
Ye, X, Fels, D, Tovmasyan, A, Aird, KM, Dedeugd, C, Allensworth, JL, Kos, I, Park, W, Spasojevic, I, Devi, GR, Dewhirst, MW, Leong, KW, and Batinic-Haberle, I. "Cytotoxic effects of Mn(III) N-alkylpyridylporphyrins in the presence of cellular reductant, ascorbate." Free Radic Res 45.11-12 (November 2011): 1289-1306.
PMID
21859376
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
45
Issue
11-12
Publish Date
2011
Start Page
1289
End Page
1306
DOI
10.3109/10715762.2011.616199

A comparative study of antioxidative activities of cell-wall polysaccharides.

Oxidative burst in plants is elicited by biotic and abiotic stressors. Analogously to some monosaccharides which act as intracellular antioxidants, cell-wall polysaccharides may be in charge of buffering free-radical production in the extracellular compartment under pronounced prooxidative settings. Although a wide range of plant polysaccharides have been examined for their antioxidative properties, this usually has not been done in a coherent and comparative manner and against biologically relevant reactive species. Here we show that different cell-wall polysaccharides, cellulose, pectin, D-galacto-D-mannan, arabinogalactan, and xylan, exhibit distinctive antioxidative activities against the hydroxyl radical (·OH)-generating Fenton reaction and superoxide. We found, using an EPR spin-trapping method, that the main carriers of 'anti-Fenton' activity in the plant cell wall are pectin and xylan. They most likely act by binding metal ions in such a manner to allow the Fenton reaction, after which they scavenge ·OH. Such a mode of action is preferred by cells resulting in a safe degradation of H(2)O(2). On the other hand, the polysaccharides examined showed similar superoxide scavenging capacities. We propose that plants may employ different antioxidative characteristics of polysaccharides to regulate their redox status by modifying the composition of the cell wall.

Authors
Pristov, JB; Mitrović, A; Spasojević, I
MLA Citation
Pristov, JB, Mitrović, A, and Spasojević, I. "A comparative study of antioxidative activities of cell-wall polysaccharides." Carbohydrate research 346.14 (October 2011): 2255-2259.
PMID
21880306
Source
epmc
Published In
Carbohydrate Research
Volume
346
Issue
14
Publish Date
2011
Start Page
2255
End Page
2259
DOI
10.1016/j.carres.2011.07.015

Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats.

This study aimed to clarify the possible therapeutic benefit of preferential nitric oxide synthase (NOS) inhibition and catalytic antioxidant Mn (III) meso-tetrakis (N-n-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP(5+)) treatment in a rat model of elevated intraocular pressure (EIOP). Rats were randomly divided into different experimental groups which received either intraperitoneal MnTnHex-2-PyP(5+) (0.1 mg/kg/day), intragastric NOS inhibitor (S-methylthiourea: SMT; 5 mg/kg/day) or both agents for a period of 6 weeks. Ocular hypertension was induced by unilaterally cauterizing three episcleral vessels and the unoperated eye served as control. Neuroprotective effects of given treatments were determined via electrophysiological measurements of visual evoked potentials (VEP) while retina and vitreous levels of MnTnHex-2-PyP(5+) were measured via LC-MS/MS. Latencies of all VEP components (P(1), N(1), P(2), N(2), P(3)) were significantly prolonged (p < 0.05) in EIOP and returned to control levels following all three treatment protocols. Ocular hypertension significantly increased retinal protein nitration (p < 0.001) which returned to baseline levels in all treated groups. NOS-2 expression and nitrate/nitrite levels were significantly greater in non-treated rats with EIOP. Retinal TUNEL staining showed apoptosis in all ocular hypertensive rats. The presented data confirm the role of oxidative injury in EIOP and highlight the protective effect of MnTnHex-2-PyP(5+) treatment and NOS inhibition in ocular hypertension.

Authors
Dogan, S; Unal, M; Ozturk, N; Yargicoglu, P; Cort, A; Spasojevic, I; Batinic-Haberle, I; Aslan, M
MLA Citation
Dogan, S, Unal, M, Ozturk, N, Yargicoglu, P, Cort, A, Spasojevic, I, Batinic-Haberle, I, and Aslan, M. "Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats." Exp Eye Res 93.4 (October 2011): 387-396.
PMID
21669199
Source
pubmed
Published In
Experimental Eye Research
Volume
93
Issue
4
Publish Date
2011
Start Page
387
End Page
396
DOI
10.1016/j.exer.2011.05.008

Diverse functions of cationic Mn(III) N-substituted pyridylporphyrins, recognized as SOD mimics.

Oxidative stress, a redox imbalance between the endogenous reactive species and antioxidant systems, is common to numerous pathological conditions such as cancer, central nervous system injuries, radiation injury, diabetes etc. Therefore, compounds able to reduce oxidative stress have been actively sought for over 3 decades. Superoxide is the major species involved in oxidative stress either in its own right or through its progeny, such as ONOO⁻, H₂O₂, •OH, CO₃•⁻, and •NO₂. Hence, the very first compounds developed in the late 1970-ies were the superoxide dismutase (SOD) mimics. Thus far the most potent mimics have been the cationic meso Mn(III) N-substituted pyridylporphyrins and N,N'-disubstituted imidazolylporphyrins (MnPs), some of them with k(cat)(O₂·⁻) similar to the k(cat) of SOD enzymes. Most frequently studied are ortho isomers MnTE-2-PyP⁵⁺, MnTnHex-2-PyP⁵⁺, and MnTDE-2-ImP⁵⁺. The ability to disproportionate O₂·⁻ parallels their ability to remove the other major oxidizing species, peroxynitrite, ONOO⁻. The same structural feature that gives rise to the high k(cat)(O₂·⁻) and k(red)(ONOO⁻), allows MnPs to strongly impact the activation of the redox-sensitive transcription factors, HIF-1α, NF-κB, AP-1, and SP-1, and therefore modify the excessive inflammatory and immune responses. Coupling with cellular reductants and other redox-active endogenous proteins seems to be involved in the actions of Mn porphyrins. While hydrophilic analogues, such as MnTE-2-PyP⁵⁺ and MnTDE-2-ImP⁵⁺ are potent in numerous animal models of diseases, the lipophilic analogues, such as MnTnHex-2-PyP⁵⁺, were developed to cross blood brain barrier and target central nervous system and critical cellular compartments, mitochondria. The modification of its structure, aimed to preserve the SOD-like potency and lipophilicity, and diminish the toxicity, has presently been pursued. The pulmonary radioprotection by MnTnHex-2-PyP⁵⁺ was the first efficacy study performed successfully with non-human primates. The Phase I toxicity clinical trials were done on amyotrophic lateral sclerosis patients with N,N'-diethylimidazolium analogue, MnTDE-2-ImP⁵⁺ (AEOL10150). Its aggressive development as a wide spectrum radioprotector by Aeolus Pharmaceuticals has been supported by USA Federal government. The latest generation of compounds, bearing oxygens in pyridyl substituents is presently under aggressive development for cancer and CNS injuries at Duke University and is supported by Duke Translational Research Institute, The Wallace H. Coulter Translational Partners Grant Program, Preston Robert Tisch Brain Tumor Center at Duke, and National Institute of Allergy and Infectious Diseases. Metal center of cationic MnPs easily accepts and donates electrons as exemplified in the catalysis of O₂·⁻ dismutation. Thus such compounds may be equally good anti- and pro-oxidants; in either case the beneficial therapeutic effects may be observed. Moreover, while the in vivo effects may appear antioxidative, the mechanism of action of MnPs that produced such effects may be pro-oxidative; the most obvious example being the inhibition of NF-κB. The experimental data therefore teach us that we need to distinguish between the mechanism/s of action/s of MnPs and the effects we observe. A number of factors impact the type of action of MnPs leading to favorable therapeutic effects: levels of reactive species and oxygen, levels of endogenous antioxidants (enzymes and low-molecular compounds), levels of MnPs, their site of accumulation, and the mutual encounters of all of those species. The complexity of in vivo redox systems and the complex redox chemistry of MnPs challenge and motivate us to further our understanding of the physiology of the normal and diseased cell with ultimate goal to successfully treat human diseases.

Authors
Batinic-Haberle, I; Rajic, Z; Tovmasyan, A; Reboucas, JS; Ye, X; Leong, KW; Dewhirst, MW; Vujaskovic, Z; Benov, L; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Rajic, Z, Tovmasyan, A, Reboucas, JS, Ye, X, Leong, KW, Dewhirst, MW, Vujaskovic, Z, Benov, L, and Spasojevic, I. "Diverse functions of cationic Mn(III) N-substituted pyridylporphyrins, recognized as SOD mimics." Free Radic Biol Med 51.5 (September 1, 2011): 1035-1053. (Review)
PMID
21616142
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
51
Issue
5
Publish Date
2011
Start Page
1035
End Page
1053
DOI
10.1016/j.freeradbiomed.2011.04.046

Neuroprotective efficacy from a lipophilic redox-modulating Mn(III) N-Hexylpyridylporphyrin, MnTnHex-2-PyP: rodent models of ischemic stroke and subarachnoid hemorrhage.

Intracerebroventricular treatment with redox-regulating Mn(III) N-hexylpyridylporphyrin (MnPorphyrin) is remarkably efficacious in experimental central nervous system (CNS) injury. Clinical development has been arrested because of poor blood-brain barrier penetration. Mn(III) meso-tetrakis (N-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP) was synthesized to include four six-carbon (hexyl) side chains on the core MnPorphyrin structure. This has been shown to increase in vitro lipophilicity 13,500-fold relative to the hydrophilic ethyl analog Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP). In normal mice, we found brain MnTnHex-2-PyP accumulation to be ∼9-fold greater than MnTE-2-PyP 24 h after a single intraperitoneal dose. We then evaluated MnTnHex-2-PyP efficacy in outcome-oriented models of focal cerebral ischemia and subarachnoid hemorrhage. For focal ischemia, rats underwent 90-min middle cerebral artery occlusion. Parenteral MnTnHex-2-PyP treatment began 5 min or 6 h after reperfusion onset and continued for 7 days. Neurologic function was improved with both early (P = 0.002) and delayed (P = 0.002) treatment onset. Total infarct size was decreased with both early (P = 0.03) and delayed (P = 0.01) treatment. MnTnHex-2-PyP attenuated nuclear factor κB nuclear DNA binding activity and suppressed tumor necrosis factor-α and interleukin-6 expression. For subarachnoid hemorrhage, mice underwent perforation of the anterior cerebral artery and were treated with intraperitoneal MnTnHex-2-PyP or vehicle for 3 days. Neurologic function was improved (P = 0.02), and vasoconstriction of the anterior cerebral (P = 0.0005), middle cerebral (P = 0.003), and internal carotid (P = 0.015) arteries was decreased by MnTnHex-2-PyP. Side-chain elongation preserved MnPorphyrin redox activity, but improved CNS bioavailability sufficient to cause improved outcome from acute CNS injury, despite delay in parenteral treatment onset of up to 6 h. This advance now allows consideration of MnPorphyrins for treatment of cerebrovascular disease.

Authors
Sheng, H; Spasojevic, I; Tse, HM; Jung, JY; Hong, J; Zhang, Z; Piganelli, JD; Batinic-Haberle, I; Warner, DS
MLA Citation
Sheng, H, Spasojevic, I, Tse, HM, Jung, JY, Hong, J, Zhang, Z, Piganelli, JD, Batinic-Haberle, I, and Warner, DS. "Neuroprotective efficacy from a lipophilic redox-modulating Mn(III) N-Hexylpyridylporphyrin, MnTnHex-2-PyP: rodent models of ischemic stroke and subarachnoid hemorrhage." J Pharmacol Exp Ther 338.3 (September 2011): 906-916.
PMID
21652782
Source
pubmed
Published In
The Journal of pharmacology and experimental therapeutics
Volume
338
Issue
3
Publish Date
2011
Start Page
906
End Page
916
DOI
10.1124/jpet.110.176701

Antihelminth compound niclosamide downregulates Wnt signaling and elicits antitumor responses in tumors with activating APC mutations.

Wnt/β-catenin pathway activation caused by adenomatous polyposis coli (APC) mutations occurs in approximately 80% of sporadic colorectal cancers (CRC). The antihelminth compound niclosamide downregulates components of the Wnt pathway, specifically Dishevelled-2 (Dvl2) expression, resulting in diminished downstream β-catenin signaling. In this study, we determined whether niclosamide could inhibit the Wnt/β-catenin pathway in human CRCs and whether its inhibition might elicit antitumor effects in the presence of APC mutations. We found that niclosamide inhibited Wnt/β-catenin pathway activation, downregulated Dvl2, decreased downstream β-catenin signaling, and exerted antiproliferative effects in human colon cancer cell lines and CRC cells isolated by surgical resection of metastatic disease, regardless of mutations in APC. In contrast, inhibition of NF-κB or mTOR did not exert similar antiproliferative effects in these CRC model systems. In mice implanted with human CRC xenografts, orally administered niclosamide was well tolerated, achieved plasma and tumor levels associated with biologic activity, and led to tumor control. Our findings support clinical explorations to reposition niclosamide for the treatment of CRC.

Authors
Osada, T; Chen, M; Yang, XY; Spasojevic, I; Vandeusen, JB; Hsu, D; Clary, BM; Clay, TM; Chen, W; Morse, MA; Lyerly, HK
MLA Citation
Osada, T, Chen, M, Yang, XY, Spasojevic, I, Vandeusen, JB, Hsu, D, Clary, BM, Clay, TM, Chen, W, Morse, MA, and Lyerly, HK. "Antihelminth compound niclosamide downregulates Wnt signaling and elicits antitumor responses in tumors with activating APC mutations." Cancer Res 71.12 (June 15, 2011): 4172-4182.
PMID
21531761
Source
pubmed
Published In
Cancer Research
Volume
71
Issue
12
Publish Date
2011
Start Page
4172
End Page
4182
DOI
10.1158/0008-5472.CAN-10-3978

Free radicals and antioxidants at a glance using EPR spectroscopy.

The delicate balance between the advantageous and detrimental effects of free radicals is one of the important aspects of human (patho)physiology. The controlled production of reactive oxygen and nitrogen species has an essential role in the regulation of various signaling switches. On the other hand, imbalanced generation of radicals is highly correlated with the pathogenesis of many diseases which require the application of selected antioxidants to regain the homeostasis. In the era of growing interest for redox processes, electron paramagnetic resonance (EPR) spectroscopy is arguably the best-suited technique for such research due to its ability to provide a unique insight into the world of free radicals and antioxidants. Herein, I present the principles of EPR spectroscopy and the applications of this method in assessing: (i) the oxidative status of biological systems, using endogenous long-lived free radicals (ascorbyl radical (Asc(•)), tocopheroxyl radical (TO(•)), melanin) as markers; (ii) the production of short-lived radicals (hydroxyl radical (OH(•)), superoxide radical anion (O(2)(•-)), sulfur- and carbon-centered radicals), which are implicated in both, oxidative stress and redox signaling; (iii) the metabolism of nitric oxide (NO(•)); (iv) the antioxidative properties of various drugs, compounds, and natural products; (v) other redox-relevant parameter. Besides giving a comprehensive survey of up-to-date literature, I also provide illustrative examples in sufficient detail to provide a means to exploit the potential of EPR in biochemical/physiological/medical research. The emphasis is on the features and characteristics (both positive and negative) relevant for EPR application in clinical sciences. My aim is to encourage fellow colleagues interested in free radicals and antioxidants to expand their base knowledge or methods used in their laboratories with data acquired by EPR or some of the EPR techniques outlined in this review, in order to boost up the exciting area of redox science.

Authors
Spasojević, I
MLA Citation
Spasojević, I. "Free radicals and antioxidants at a glance using EPR spectroscopy." Critical reviews in clinical laboratory sciences 48.3 (May 2011): 114-142. (Review)
PMID
21875311
Source
epmc
Published In
Critical Reviews in Clinical Laboratory Sciences (Informa)
Volume
48
Issue
3
Publish Date
2011
Start Page
114
End Page
142
DOI
10.3109/10408363.2011.591772

Methoxy-derivatization of alkyl chains increases the in vivo efficacy of cationic Mn porphyrins. Synthesis, characterization, SOD-like activity, and SOD-deficient E. coli study of meta Mn(III) N-methoxyalkylpyridylporphyrins.

Cationic Mn(III) N-alkylpyridylporphyrins (MnPs) are potent SOD mimics and peroxynitrite scavengers and diminish oxidative stress in a variety of animal models of central nervous system (CNS) injuries, cancer, radiation, diabetes, etc. Recently, properties other than antioxidant potency, such as lipophilicity, size, shape, and bulkiness, which influence the bioavailability and the toxicity of MnPs, have been addressed as they affect their in vivo efficacy and therapeutic utility. Porphyrin bearing longer alkyl substituents at pyridyl ring, MnTnHex-2-PyP(5+), is more lipophilic, thus more efficacious in vivo, particularly in CNS injuries, than the shorter alkyl-chained analog, MnTE-2-PyP(5+). Its enhanced lipophilicity allows it to accumulate in mitochondria (relative to cytosol) and to cross the blood-brain barrier to a much higher extent than MnTE-2-PyP(5+). Mn(III) N-alkylpyridylporphyrins of longer alkyl chains, however, bear micellar character, and when used at higher levels, become toxic. Recently we showed that meta isomers are ∼10-fold more lipophilic than ortho species, which enhances their cellular accumulation, and thus reportedly compensates for their somewhat inferior SOD-like activity. Herein, we modified the alkyl chains of the lipophilic meta compound, MnTnHex-3-PyP(5+) via introduction of a methoxy group, to diminish its toxicity (and/or enhance its efficacy), while maintaining high SOD-like activity and lipophilicity. We compared the lipophilic Mn(III) meso-tetrakis(N-(6'-methoxyhexyl)pyridinium-3-yl)porphyrin, MnTMOHex-3-PyP(5+), to a hydrophilic Mn(III) meso-tetrakis(N-(2'-methoxyethyl)pyridinium-3-yl)porphyrin, MnTMOE-3-PyP(5+). The compounds were characterized by uv-vis spectroscopy, mass spectrometry, elemental analysis, electrochemistry, and ability to dismute O(2)˙(-). Also, the lipophilicity was characterized by thin-layer chromatographic retention factor, R(f). The SOD-like activities and metal-centered reduction potentials for the Mn(III)P/Mn(II)P redox couple were similar-to-identical to those of N-alkylpyridyl analogs: log k(cat) = 6.78, and E(1/2) = +68 mV vs. NHE (MnTMOHex-3-PyP(5+)), and log k(cat) = 6.72, and E(1/2) = +64 mV vs. NHE (MnTMOE-3-PyP(5+)). The compounds were tested in a superoxide-specific in vivo model: aerobic growth of SOD-deficient E. coli, JI132. Both MnTMOHex-3-PyP(5+) and MnTMOE-3-PyP(5+) were more efficacious than their alkyl analogs. MnTMOE-3-PyP(5+) is further significantly more efficacious than the most explored compound in vivo, MnTE-2-PyP(5+). Such a beneficial effect of MnTMOE-3-PyP(5+) on diminished toxicity, improved efficacy and transport across the cell wall may originate from the favorable interplay of the size, length of pyridyl substituents, rotational flexibility (the ortho isomer, MnTE-2-PyP(5+), is more rigid, while MnTMOE-3-PyP(5+) is a more flexible meta isomer), bulkiness and presence of oxygen.

Authors
Tovmasyan, AG; Rajic, Z; Spasojevic, I; Reboucas, JS; Chen, X; Salvemini, D; Sheng, H; Warner, DS; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, AG, Rajic, Z, Spasojevic, I, Reboucas, JS, Chen, X, Salvemini, D, Sheng, H, Warner, DS, Benov, L, and Batinic-Haberle, I. "Methoxy-derivatization of alkyl chains increases the in vivo efficacy of cationic Mn porphyrins. Synthesis, characterization, SOD-like activity, and SOD-deficient E. coli study of meta Mn(III) N-methoxyalkylpyridylporphyrins." Dalton Trans 40.16 (April 28, 2011): 4111-4121.
PMID
21384047
Source
pubmed
Published In
Dalton Transactions
Volume
40
Issue
16
Publish Date
2011
Start Page
4111
End Page
4121
DOI
10.1039/c0dt01321h

Effects of aerobic training on oxidative status in postsurgical non-small cell lung cancer patients: a pilot study.

BACKGROUND: Oxidative stress is postulated to contribute to the initiation, promotion, and progression of non-small cell lung cancer (NSCLC). We investigated the effects of supervised, moderate-intensity aerobic training on urinary markers of oxidative status in patients with postsurgical NSCLC. PATIENTS AND METHODS: Sixteen patients with histologically confirmed stage I-IIIB NSCLC were recruited. Exercise training consisted of aerobic cycle ergometry sessions at 60 to ≥70% of baseline peak workload 20-45 min·d(-1), 3 d·wk(-1)for 14 weeks. Oxidative status was assessed via four urinary F(2)-isoprostanes isomers: iPF (2-alpha)-III, 2,3-dinor-iPF(2 alpha)-III, iPF (2-alpha)-VI, and 8,12-iso-iPF(2 alpha)-VI using liquid chromatography with tandem mass spectrometry detection. Peak oxygen consumption (VO2peak) was assessed using a maximal, incremental, cardiopulmonary exercise test with expired gas analysis. RESULTS: A composite index of all four F2-isoprostanes isomers increased from baseline to post-intervention by 32% (p = 0.08). Concerning individual isomers, iPF (2-alpha)-III increased by 0.09 (+55%; p = .010), iPF (2-alpha)-VI by 0.81 (+29%; p = 0.04), and 8,12-iso-iPF(2 alpha)-VI by 0.59 (+28%; p = 0.07) from baseline to postintervention. There was no change in 2,3-dinor-iPF(2 alpha)-III levels. VO2peak increased 1.1 mL·kg·(-1) min(-1) (p = 0.14) and peak workload increased 10 Watts (p < .001). Change in VO2peak was not associated with change in markers of oxidative status. CONCLUSIONS: Aerobic training was associated with significant increases in urinary measures of oxidative status in postsurgical NSCLC. The clinical implications of these findings are currently unknown. Further studies are required to elucidate the complex relationship between aerobic training, oxidative stress, tumor biology, and response to cytotoxic agents in mouse and human models of cancer.

Authors
Jones, LW; Eves, ND; Spasojevic, I; Wang, F; Il'yasova, D
MLA Citation
Jones, LW, Eves, ND, Spasojevic, I, Wang, F, and Il'yasova, D. "Effects of aerobic training on oxidative status in postsurgical non-small cell lung cancer patients: a pilot study." Lung Cancer 72.1 (April 2011): 45-51.
PMID
20863590
Source
pubmed
Published In
Lung Cancer
Volume
72
Issue
1
Publish Date
2011
Start Page
45
End Page
51
DOI
10.1016/j.lungcan.2010.08.002

Profiling the effects of isocitrate dehydrogenase 1 and 2 mutations on the cellular metabolome.

Point mutations of the NADP(+)-dependent isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) occur early in the pathogenesis of gliomas. When mutated, IDH1 and IDH2 gain the ability to produce the metabolite (R)-2-hydroxyglutarate (2HG), but the downstream effects of mutant IDH1 and IDH2 proteins or of 2HG on cellular metabolism are unknown. We profiled >200 metabolites in human oligodendroglioma (HOG) cells to determine the effects of expression of IDH1 and IDH2 mutants. Levels of amino acids, glutathione metabolites, choline derivatives, and tricarboxylic acid (TCA) cycle intermediates were altered in mutant IDH1- and IDH2-expressing cells. These changes were similar to those identified after treatment of the cells with 2HG. Remarkably, N-acetyl-aspartyl-glutamate (NAAG), a common dipeptide in brain, was 50-fold reduced in cells expressing IDH1 mutants and 8.3-fold reduced in cells expressing IDH2 mutants. NAAG also was significantly lower in human glioma tissues containing IDH mutations than in gliomas without such mutations. These metabolic changes provide clues to the pathogenesis of tumors associated with IDH gene mutations.

Authors
Reitman, ZJ; Jin, G; Karoly, ED; Spasojevic, I; Yang, J; Kinzler, KW; He, Y; Bigner, DD; Vogelstein, B; Yan, H
MLA Citation
Reitman, ZJ, Jin, G, Karoly, ED, Spasojevic, I, Yang, J, Kinzler, KW, He, Y, Bigner, DD, Vogelstein, B, and Yan, H. "Profiling the effects of isocitrate dehydrogenase 1 and 2 mutations on the cellular metabolome." Proc Natl Acad Sci U S A 108.8 (February 22, 2011): 3270-3275.
PMID
21289278
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
108
Issue
8
Publish Date
2011
Start Page
3270
End Page
3275
DOI
10.1073/pnas.1019393108

2-hydroxyglutarate production, but not dominant negative function, is conferred by glioma-derived NADP-dependent isocitrate dehydrogenase mutations.

BACKGROUND: Gliomas frequently contain mutations in the cytoplasmic NADP(+)-dependent isocitrate dehydrogenase (IDH1) or the mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDH2). Several different amino acid substitutions recur at either IDH1 R132 or IDH2 R172 in glioma patients. Genetic evidence indicates that these mutations share a common gain of function, but it is unclear whether the shared function is dominant negative activity, neomorphic production of (R)-2-hydroxyglutarate (2HG), or both. METHODOLOGY/PRINCIPAL FINDINGS: We show by coprecipitation that five cancer-derived IDH1 R132 mutants bind IDH1-WT but that three cancer-derived IDH2 R172 mutants exert minimal binding to IDH2-WT. None of the mutants dominant-negatively lower isocitrate dehydrogenase activity at physiological (40 µM) isocitrate concentrations in mammalian cell lysates. In contrast to this, all of these mutants confer 10- to 100-fold higher 2HG production to cells, and glioma tissues containing IDH1 R132 or IDH2 R172 mutations contain high levels of 2HG compared to glioma tissues without IDH mutations (54.4 vs. 0.1 mg 2HG/g protein). CONCLUSIONS: Binding to, or dominant inhibition of, WT IDH1 or IDH2 is not a shared feature of the IDH1 and IDH2 mutations, and thus is not likely to be important in cancer. The fact that the gain of the enzymatic activity to produce 2HG is a shared feature of the IDH1 and IDH2 mutations suggests that this is an important function for these mutants in driving cancer pathogenesis.

Authors
Jin, G; Reitman, ZJ; Spasojevic, I; Batinic-Haberle, I; Yang, J; Schmidt-Kittler, O; Bigner, DD; Yan, H
MLA Citation
Jin, G, Reitman, ZJ, Spasojevic, I, Batinic-Haberle, I, Yang, J, Schmidt-Kittler, O, Bigner, DD, and Yan, H. "2-hydroxyglutarate production, but not dominant negative function, is conferred by glioma-derived NADP-dependent isocitrate dehydrogenase mutations. (Published online)" PLoS One 6.2 (February 4, 2011): e16812-.
PMID
21326614
Source
pubmed
Published In
PloS one
Volume
6
Issue
2
Publish Date
2011
Start Page
e16812
DOI
10.1371/journal.pone.0016812

The negative effect of soy extract on erythrocyte membrane fluidity: an electron paramagnetic resonance study.

A decrease of erythrocyte membrane fluidity can contribute to the pathophysiology of hypertension. Soy products, which are used as alternative therapeutics in some cardiovascular conditions, contain various isoflavones (genistein, daidzein, and their glucosides, genistin and daidzin), which can incorporate cellular membrane and change its fluidity. The aim of this study was to examine the effects of soy extract (which generally corresponds to the soy products of isoflavone composition) on erythrocyte membrane fluidity at graded depths. We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 12-DS), the spectra of which are dependent on membrane fluidity. After being treated with soy extract, erythrocytes showed a significant (P = 0.016) decrease of membrane fluidity near the hydrophilic surface, while there were no significant changes of fluidity in deeper hydrophobic membrane regions. These results suggest that soy products containing high levels of genistein and isoflavone glucosides may not be suitable for use in hypertension because they decrease erythrocyte membrane fluidity.

Authors
Ajdžanović, V; Spasojević, I; Sošić-Jurjević, B; Filipović, B; Trifunović, S; Sekulić, M; Milošević, V
MLA Citation
Ajdžanović, V, Spasojević, I, Sošić-Jurjević, B, Filipović, B, Trifunović, S, Sekulić, M, and Milošević, V. "The negative effect of soy extract on erythrocyte membrane fluidity: an electron paramagnetic resonance study." The Journal of membrane biology 239.3 (February 2011): 131-135.
PMID
21132426
Source
epmc
Published In
The Journal of Membrane Biology
Volume
239
Issue
3
Publish Date
2011
Start Page
131
End Page
135
DOI
10.1007/s00232-010-9332-8

Relevance of the ability of fructose 1,6-bis(phosphate) to sequester ferrous but not ferric ions.

The cytoprotective activity of F16BP has been documented in severe conditions such as convulsions, reperfusion injury, septic shock, diabetic complications, hypothermia-induced injury, UV-provoked skin damage and in other processes including apoptosis and excitotoxicity. F16BP shows very efficient cytoprotective activity in astroglial cells exposed to H(2)O(2)-provoked oxidative stress and during neuronal injury caused by hypoxic conditions. As most of the aforementioned processes involve iron activity-related conditions, we investigated the ferric and ferrous iron binding properties of F16BP under physiological conditions using (31)P NMR and EPR spectroscopy. Our results indicate that cytoprotective F16BP activity is predominantly based on ferrous iron sequestration. (31)P NMR spectroscopy of F16BP employing paramagnetic properties of iron clearly showed that F16BP forms stabile complexes with Fe(2+) which was verified by EPR of another divalent cation-Mn(2+). On the other hand, F16BP does not sequester ferric iron nor does it increase its redox activity as shown by (31)P NMR and EPR spin-trapping. Therefore, F16BP may be beneficial in neurodegenerative and other conditions that are characterised by ferric iron stores and deposits.

Authors
Bajić, A; Zakrzewska, J; Godjevac, D; Andjus, P; Jones, DR; Spasić, M; Spasojević, I
MLA Citation
Bajić, A, Zakrzewska, J, Godjevac, D, Andjus, P, Jones, DR, Spasić, M, and Spasojević, I. "Relevance of the ability of fructose 1,6-bis(phosphate) to sequester ferrous but not ferric ions." Carbohydrate research 346.3 (February 2011): 416-420.
PMID
21232735
Source
epmc
Published In
Carbohydrate Research
Volume
346
Issue
3
Publish Date
2011
Start Page
416
End Page
420
DOI
10.1016/j.carres.2010.12.008

Bioavailability of metalloporphyrin-based SOD mimics is greatly influenced by a single charge residing on a Mn site.

In the cell Mn porphyrins (MnPs) likely couple with cellular reductants which results in a drop of total charge from 5+ to 4+ and dramatically increases their lipophilicity by up to three orders of magnitude depending upon the length of alkylpyridyl chains and type of isomer. The effects result from the interplay of solvation, lipophilicit and stericity. Impact of ascorbate on accumulation of MnPs was measured in E. coli and in Balb/C mouse tumours and muscle; for the latter measurements, the LC/ESI-MS/MS method was developed. Accumulation was significantly enhanced when MnPs were co-administered with ascorbate in both prokaryotic and eukaryotic systems. Further, MnTnHex-2-PyP(5+) accumulates 5-fold more in the tumour than in a muscle. Such data increase our understanding of MnPs cellular and sub-cellular accumulation and remarkable in vivo effects. The work is in progress to understand how coupling of MnPs with ascorbate affects their mechanism of action, in particular with respect to cancer therapy.

Authors
Spasojevic, I; Kos, I; Benov, LT; Rajic, Z; Fels, D; Dedeugd, C; Ye, X; Vujaskovic, Z; Reboucas, JS; Leong, KW; Dewhirst, MW; Batinic-Haberle, I
MLA Citation
Spasojevic, I, Kos, I, Benov, LT, Rajic, Z, Fels, D, Dedeugd, C, Ye, X, Vujaskovic, Z, Reboucas, JS, Leong, KW, Dewhirst, MW, and Batinic-Haberle, I. "Bioavailability of metalloporphyrin-based SOD mimics is greatly influenced by a single charge residing on a Mn site." Free Radic Res 45.2 (February 2011): 188-200.
PMID
20942564
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
45
Issue
2
Publish Date
2011
Start Page
188
End Page
200
DOI
10.3109/10715762.2010.522575

Bench-to-bedside review: sepsis - from the redox point of view.

The pathogenesis of sepsis and its progression to multiple organ dysfunction syndrome and septic shock have been the subject of investigations for nearly half a century. Controversies still exist with regard to understanding the molecular pathophysiology of sepsis in relation to the complex roles played by reactive oxygen species, nitric oxide, complements and cytokines. In the present review we categorise the key turning points in sepsis development and outline the most probable sequence of events leading to cellular dysfunction and organ failure under septic conditions. We have applied an integrative approach in order to fuse current state-of-the-art knowledge about redox processes involving hydrogen peroxide, nitric oxide, superoxide, peroxynitrite and hydroxyl radical, which lead to mitochondrial respiratory dysfunction. Finally, from this point of view, the potential of redox therapy targeting sepsis is discussed.

Authors
Andrades, MÉ; Morina, A; Spasić, S; Spasojević, I
MLA Citation
Andrades, MÉ, Morina, A, Spasić, S, and Spasojević, I. "Bench-to-bedside review: sepsis - from the redox point of view." Critical care (London, England) 15.5 (January 2011): 230-. (Review)
PMID
21996422
Source
epmc
Published In
Critical Care
Volume
15
Issue
5
Publish Date
2011
Start Page
230
DOI
10.1186/cc10334

Individual responses to chemotherapy-induced oxidative stress.

Differences in redox homeostatic control between cancer patients may underlie predisposition to drug resistance and toxicities. To evaluate interindividual differences in redox response among newly diagnosed breast cancer patients undergoing standard chemotherapy, urine samples were collected before (T0), and at 1 (T1) and 24 h (T24) after chemotherapy administration. Oxidative status was assessed by urinary levels of allantoin and four F2-isoprostanes, quantified by LC-MS/MS. In all subjects, biomarker levels increased at T1 and returned to baseline at T24. Analyzing individual responses, two patterns were revealed: 10 subjects showed uniform increases of biomarker levels at T1 ("increase" pattern) and 8 subjects showed mixed (increase/unchanged/decrease) responses for different biomarkers ("mixed" pattern). The increase-pattern group had lower pre-treatment (T0) levels of the biomarkers and showed a sharp increase at T1 (64-141%) with a subsequent decrease at T24. The mixed-pattern group had higher pre-treatment biomarker levels and showed no change in biomarkers either at T1 or at T24. These findings indicate that there may be at least two distinct redox phenotypes with different homeostatic mechanisms balancing oxidative stress in humans. Recognizing redox phenotypes in human populations may lead to more precise assessment of health risks and benefits associated with individual redox make-up, and may also help to identify cancer patients who are especially susceptible to drug resistance and/or drug toxicity.

Authors
Il'yasova, D; Kennedy, K; Spasojevic, I; Wang, F; Tolun, AA; Base, K; Young, SP; Kelly Marcom, P; Marks, J; Millington, DS; Dewhirst, MW
MLA Citation
Il'yasova, D, Kennedy, K, Spasojevic, I, Wang, F, Tolun, AA, Base, K, Young, SP, Kelly Marcom, P, Marks, J, Millington, DS, and Dewhirst, MW. "Individual responses to chemotherapy-induced oxidative stress." Breast Cancer Res Treat 125.2 (January 2011): 583-589.
PMID
20830514
Source
pubmed
Published In
Breast Cancer Research and Treatment
Volume
125
Issue
2
Publish Date
2011
Start Page
583
End Page
589
DOI
10.1007/s10549-010-1158-7

The role of EPR spectroscopy in studies of the oxidative status of biological systems and the antioxidative properties of various compounds

Authors
Spasojevic, I; Mojovic, M; Ignjatovic, A; Bacic, G
MLA Citation
Spasojevic, I, Mojovic, M, Ignjatovic, A, and Bacic, G. "The role of EPR spectroscopy in studies of the oxidative status of biological systems and the antioxidative properties of various compounds." Journal of the Serbian Chemical Society 76.5 (2011): 647-677.
Source
crossref
Published In
Journal of the Serbian Chemical Society
Volume
76
Issue
5
Publish Date
2011
Start Page
647
End Page
677
DOI
10.2298/JSC101015064S

Response to Rosenthal et al.

Authors
Batinic-Haberle, I; Reboucas, JS; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Reboucas, JS, and Spasojevic, I. "Response to Rosenthal et al." Antioxidants and Redox Signaling 14.6 (2011): 1174-1176.
Source
scival
Published In
Antioxidants & Redox Signaling
Volume
14
Issue
6
Publish Date
2011
Start Page
1174
End Page
1176
DOI
10.1089/ars.2010.3758.rs

The potential physiological implications of polygalacturonic acid-mediated production of superoxide.

PGA/OGA/PF represent apoplastic signaling molecules implicated in the control of gene expression and the activity of enzymes involved in defense regulation. However, the underlying mechanisms behind such processes are lacking. Here we unequivocally show using EPR spectroscopy with DEPMPO spin-trap capable of differentiating between •OH and •O(2)(-) that PGA and PF can produce •O(2)(-) by transforming •OH. The potential physiological implications of this unique property are discussed. We propose that PGA/OGA/PF could represent the initiators of redox signaling cascades in stress response, with H(2)O(2) being a downstream secondary messenger.

Authors
Spasojević, I; Pristov, JB
MLA Citation
Spasojević, I, and Pristov, JB. "The potential physiological implications of polygalacturonic acid-mediated production of superoxide." Plant signaling & behavior 5.12 (December 2010): 1525-1529.
PMID
21139441
Source
epmc
Published In
Plant signaling & behavior
Volume
5
Issue
12
Publish Date
2010
Start Page
1525
End Page
1529
DOI
10.4161/psb.5.12.12838

Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential.

Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia-reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO(3)(*-), peroxyl radical, and less efficiently H(2)O(2). By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds.

Authors
Batinić-Haberle, I; Rebouças, JS; Spasojević, I
MLA Citation
Batinić-Haberle, I, Rebouças, JS, and Spasojević, I. "Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential." Antioxid Redox Signal 13.6 (September 15, 2010): 877-918. (Review)
Website
http://hdl.handle.net/10161/3344
PMID
20095865
Source
pubmed
Published In
Antioxidants & Redox Signaling
Volume
13
Issue
6
Publish Date
2010
Start Page
877
End Page
918
DOI
10.1089/ars.2009.2876

Growth hormone mitigates against lethal irradiation and enhances hematologic and immune recovery in mice and nonhuman primates.

Medications that can mitigate against radiation injury are limited. In this study, we investigated the ability of recombinant human growth hormone (rhGH) to mitigate against radiation injury in mice and nonhuman primates. BALB/c mice were irradiated with 7.5 Gy and treated post-irradiation with rhGH intravenously at a once daily dose of 20 microg/dose for 35 days. rhGH protected 17 out of 28 mice (60.7%) from lethal irradiation while only 3 out of 28 mice (10.7%) survived in the saline control group. A shorter course of 5 days of rhGH post-irradiation produced similar results. Compared with the saline control group, treatment with rhGH on irradiated BALB/c mice significantly accelerated overall hematopoietic recovery. Specifically, the recovery of total white cells, CD4 and CD8 T cell subsets, B cells, NK cells and especially platelets post radiation exposure were significantly accelerated in the rhGH-treated mice. Moreover, treatment with rhGH increased the frequency of hematopoietic stem/progenitor cells as measured by flow cytometry and colony forming unit assays in bone marrow harvested at day 14 after irradiation, suggesting the effects of rhGH are at the hematopoietic stem/progenitor level. rhGH mediated the hematopoietic effects primarily through their niches. Similar data with rhGH were also observed following 2 Gy sublethal irradiation of nonhuman primates. Our data demonstrate that rhGH promotes hematopoietic engraftment and immune recovery post the exposure of ionizing radiation and mitigates against the mortality from lethal irradiation even when administered after exposure.

Authors
Chen, BJ; Deoliveira, D; Spasojevic, I; Sempowski, GD; Jiang, C; Owzar, K; Wang, X; Gesty-Palmer, D; Cline, JM; Bourland, JD; Dugan, G; Meadows, SK; Daher, P; Muramoto, G; Chute, JP; Chao, NJ
MLA Citation
Chen, BJ, Deoliveira, D, Spasojevic, I, Sempowski, GD, Jiang, C, Owzar, K, Wang, X, Gesty-Palmer, D, Cline, JM, Bourland, JD, Dugan, G, Meadows, SK, Daher, P, Muramoto, G, Chute, JP, and Chao, NJ. "Growth hormone mitigates against lethal irradiation and enhances hematologic and immune recovery in mice and nonhuman primates. (Published online)" PLoS One 5.6 (June 16, 2010): e11056-.
Website
http://hdl.handle.net/10161/4547
PMID
20585403
Source
pubmed
Published In
PloS one
Volume
5
Issue
6
Publish Date
2010
Start Page
e11056
DOI
10.1371/journal.pone.0011056

Urinary biomarkers of oxidative status in a clinical model of oxidative assault.

BACKGROUND: We used doxorubicin-based chemotherapy as a clinical model of oxidative assault in humans. METHODS: The study recruited newly diagnosed breast cancer patients (n = 23). Urine samples were collected immediately before (T0) and at 1 hour (T1) and 24 hours (T24) after i.v. administration of treatment. Measurements included allantoin and the isoprostanes iPF(2alpha)-III, iPF(2alpha)-VI, and 8,12-iso-iPF(2alpha)-VI along with the prostaglandin 2,3-dinor-iPF(2alpha)-III, a metabolite of iPF(2alpha)-III. All biomarkers were quantified using liquid chromatography-tandem mass spectrometry. RESULTS: In all subjects, the levels of the biomarkers increased at T1: allantoin by 22% (P = 0.06), iPF(2alpha)-III by 62% (P < 0.05), iPF(2alpha)-VI by 41% (P < 0.05), 8,12-iso-iPF(2alpha)-VI by 58% (P < 0.05), and 2,3-dinor-iPF(2alpha)-III by 52% (P < 0.05). At T24, the F2-isoprostanes returned to their baseline levels; the levels of allantoin continued to increase, although the T24-T0 difference was not statistically significant. CONCLUSIONS: These results indicate that urinary F2-isoprostanes are valid biomarkers and allantoin is a promising biomarker of oxidative status in humans. IMPACT: The levels of biomarkers change quickly in response to oxidative assault and can be used to monitor oxidative status in humans in response to treatments related either to generation of free radicals (chemotherapy and radiation therapy) or to antioxidants (inborn metabolic diseases and Down syndrome).

Authors
Il'yasova, D; Spasojevic, I; Wang, F; Tolun, AA; Base, K; Young, SP; Marcom, PK; Marks, J; Mixon, G; DiGiulio, R; Millington, DS
MLA Citation
Il'yasova, D, Spasojevic, I, Wang, F, Tolun, AA, Base, K, Young, SP, Marcom, PK, Marks, J, Mixon, G, DiGiulio, R, and Millington, DS. "Urinary biomarkers of oxidative status in a clinical model of oxidative assault." Cancer Epidemiol Biomarkers Prev 19.6 (June 2010): 1506-1510.
PMID
20501773
Source
pubmed
Published In
Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
Volume
19
Issue
6
Publish Date
2010
Start Page
1506
End Page
1510
DOI
10.1158/1055-9965.EPI-10-0211

Effect of pazopanib on tumor microenvironment and liposome delivery.

Pathologic angiogenesis creates an abnormal microenvironment in solid tumors, characterized by elevated interstitial fluid pressure (IFP) and hypoxia. Emerging theories suggest that judicious downregulation of proangiogenic signaling pathways may transiently "normalize" the vascular bed, making it more suitable for drug delivery and radiotherapy. In this work, we investigate the role of pazopanib, a small-molecule inhibitor of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptors, on tumor IFP, angiogenesis, hypoxia, and liposomal drug delivery. Nude mice bearing A549 human non-small cell lung cancer xenografts were treated with 100 mg/kg pazopanib (n = 20) or vehicle (n = 20) through oral gavage for 8 days, followed by a one-time intravenous dose of 10 mg/kg Doxil (liposomal doxorubicin). Pazopanib treatment resulted in significant reduction of tumor IFP and decreased vessel density, assessed by CD31 staining. Despite these trends toward normalization, high-performance liquid chromatography revealed no differences in doxorubicin concentration between pazopanib-treated and control tumors, with Doxil penetration from microvessels being significantly reduced in the pazopanib group. Additionally, tumor hypoxia, evaluated by CA-IX immunostaining and confirmed in a second study by EF5 expression (n = 4, 100 mg/kg pazopanib; n = 4, vehicle), was increased in pazopanib-treated tumors. Our results suggest that the classic definition of tumor "normalization" may undermine the crucial role of vessel permeability and oncotic pressure gradients in liposomal drug delivery, and that functional measures of normalization, such as reduced IFP and hypoxia, may not occur in parallel temporal windows.

Authors
Tailor, TD; Hanna, G; Yarmolenko, PS; Dreher, MR; Betof, AS; Nixon, AB; Spasojevic, I; Dewhirst, MW
MLA Citation
Tailor, TD, Hanna, G, Yarmolenko, PS, Dreher, MR, Betof, AS, Nixon, AB, Spasojevic, I, and Dewhirst, MW. "Effect of pazopanib on tumor microenvironment and liposome delivery." Mol Cancer Ther 9.6 (June 2010): 1798-1808.
PMID
20515941
Source
pubmed
Published In
Molecular cancer therapeutics
Volume
9
Issue
6
Publish Date
2010
Start Page
1798
End Page
1808
DOI
10.1158/1535-7163.MCT-09-0856

PHASE I STUDY OF PERIFOSINE (AKT INHIBITOR) FOR RECURRENT PEDIATRIC SOLID TUMORS

Authors
Becher, OJ; Trippett, T; Gilheeney, S; Khakoo, Y; Lyden, D; Haque, S; Petriccione, M; Camelia, S; Lassman, A; Fischer, C; Kolesar, J; Jiang, Z; Modak, S; Holland, E; Dunkel, I
MLA Citation
Becher, OJ, Trippett, T, Gilheeney, S, Khakoo, Y, Lyden, D, Haque, S, Petriccione, M, Camelia, S, Lassman, A, Fischer, C, Kolesar, J, Jiang, Z, Modak, S, Holland, E, and Dunkel, I. "PHASE I STUDY OF PERIFOSINE (AKT INHIBITOR) FOR RECURRENT PEDIATRIC SOLID TUMORS." June 2010.
PMID
28035748
Source
wos-lite
Published In
Neuro-Oncology
Volume
12
Issue
6
Publish Date
2010
Start Page
II42
End Page
II42

Effects of genistein and daidzein on erythrocyte membrane fluidity: an electron paramagnetic resonance study.

The maintenance of erythrocyte membrane fluidity at the physiological level is an important factor affecting the ability of erythrocytes to pass through blood vessels of small luminal diameter. Genistein and daidzein, which are used as alternative therapeutics in cardiovascular conditions, can be incorporated into the cell membrane and change its fluidity. The aim of this study was to examine the effects of genistein and daidzein on erythrocyte membrane fluidity at graded depths. We used electron paramagnetic resonance (EPR) spectroscopy and fatty acid spin probes (5-DS and 12-DS) where EPR spectra were dependent on fluidity. The results showed that genistein significantly (p < 0.05) decreased erythrocyte membrane fluidity near the hydrophilic surface, while daidzein significantly (p < 0.05) increased the same parameter in deeper regions of the membrane. These data suggest that the deep fluidizing effects of daidzein on erythrocyte membranes make it a better therapeutic choice than genistein in some cardiovascular conditions.

Authors
Ajdzanović, V; Spasojević, I; Filipović, B; Sosić-Jurjević, B; Sekulić, M; Milosević, V
MLA Citation
Ajdzanović, V, Spasojević, I, Filipović, B, Sosić-Jurjević, B, Sekulić, M, and Milosević, V. "Effects of genistein and daidzein on erythrocyte membrane fluidity: an electron paramagnetic resonance study." Canadian journal of physiology and pharmacology 88.4 (April 2010): 497-500.
PMID
20555419
Source
epmc
Published In
Canadian Journal of Physiology and Pharmacology
Volume
88
Issue
4
Publish Date
2010
Start Page
497
End Page
500
DOI
10.1139/y10-020

Non-invasive monitoring of intra-tumor drug concentration and therapeutic response using optical spectroscopy.

Optical spectroscopy was used to monitor changes in tumor physiology with therapy, and its influence on drug delivery and treatment efficacy for hyperthermia treatment combined with free doxorubicin or a low-temperature sensitive liposomal formulation. Monte Carlo-based modeling techniques were used to characterize the intrinsic absorption, scattering, and fluorescence properties of tissue. Fluorescence assessment of drug concentration was validated against HPLC and found to be significantly linearly correlated (r=0.88). Cluster analysis on the physiologic data obtained by optical spectroscopy revealed two physiologic phenotypes prior to treatment. One of these was relatively hypoxic, with relatively low total hemoglobin content. This hypoxic group was found to have a significantly shorter time to reach 3 times pre-treatment volume, indicating a more treatment resistant phenotype (p=0.003). Influence of tumor physiology was assessed in more detail for the liposomal doxorubicin+hyperthermia group, which demonstrated a highly significant correlation between pre-treatment hemoglobin saturation and tumor growth delay, and also between post-hyperthermia total hemoglobin content and tumor drug delivery. Finally, it was found that the doxorubicin concentration, measured in vivo using fluorescence techniques significantly predicted for chemoresponse (hazard ratio: 0.34, p=0.0007). The ability to characterize drug delivery and tumor physiology in vivo makes this a potentially useful tool for evaluating the efficacy of targeted delivery systems in preclinical studies, and may be translatable for monitoring and predicting individual treatment responses in the clinic.

Authors
Palmer, GM; Boruta, RJ; Viglianti, BL; Lan, L; Spasojevic, I; Dewhirst, MW
MLA Citation
Palmer, GM, Boruta, RJ, Viglianti, BL, Lan, L, Spasojevic, I, and Dewhirst, MW. "Non-invasive monitoring of intra-tumor drug concentration and therapeutic response using optical spectroscopy." J Control Release 142.3 (March 19, 2010): 457-464.
PMID
19896999
Source
pubmed
Published In
Journal of Controlled Release
Volume
142
Issue
3
Publish Date
2010
Start Page
457
End Page
464
DOI
10.1016/j.jconrel.2009.10.034

Electron Paramagnetic Resonance - A Powerful Tool of Medical Biochemistry in Discovering Mechanisms of Disease and Treatment Prospects

Authors
Spasojević, I
MLA Citation
Spasojević, I. "Electron Paramagnetic Resonance - A Powerful Tool of Medical Biochemistry in Discovering Mechanisms of Disease and Treatment Prospects." Journal of Medical Biochemistry 29.3 (January 1, 2010).
Source
crossref
Published In
Journal of Medical Biochemistry
Volume
29
Issue
3
Publish Date
2010
DOI
10.2478/v10011-010-0020-0

Different roles of radical scavengers--ascorbate and urate in the cerebrospinal fluid of amyotrophic lateral sclerosis patients.

Ferrous iron, released from iron deposits in the motor cortex and other brain regions of amyotrophic lateral sclerosis (ALS) patients, participates in the Fenton reaction in cerebrospinal fluid (CSF) alongside H(2)O(2), which is continuously released by neuronal cells. In vivo, the production of notoriously reactive hydroxyl radicals via this reaction could lead to the progression of the disease. Herein, we have examined the effect of ascorbate and uric acid on the production of hydroxyl radicals in CSF from both sporadic ALS patients and control subjects. Electron paramagnetic resonance spectroscopy identified ascorbyl radicals in CSF from ALS patients whereas it was undetectable in control CSF. The addition of H(2)O(2) to the CSF from ALS patients provoked further formation of ascorbyl radicals and the formation of hydroxyl radicals ex vivo. The hydroxyl addition of uric acid to CSF from ALS patients diminished the production of hydroxyl radicals. In conclusion, there are clear differences between the roles of the two examined radical scavengers in the CSF of ALS patients indicating that the use of ascorbate could have unfavourable effects in ALS patients.

Authors
Spasojević, I; Stević, Z; Nikolić-Kokić, A; Jones, DR; Blagojević, D; Spasić, MB
MLA Citation
Spasojević, I, Stević, Z, Nikolić-Kokić, A, Jones, DR, Blagojević, D, and Spasić, MB. "Different roles of radical scavengers--ascorbate and urate in the cerebrospinal fluid of amyotrophic lateral sclerosis patients." Redox report : communications in free radical research 15.2 (January 2010): 81-86.
PMID
20500989
Source
epmc
Published In
Redox Report
Volume
15
Issue
2
Publish Date
2010
Start Page
81
End Page
86
DOI
10.1179/174329210x12650506623320

Bioavailability and catalytic properties of copper and iron for Fenton chemistry in human cerebrospinal fluid.

A breakdown in homeostasis of redox-active metals represents an important factor for neurodegeneration. We have used EPR spectroscopy and BMPO spin-trap to investigate the catalytic properties and ligand modulation of redox activity of copper and iron in human cerebrospinal fluid (CSF). In contrast to iron, copper supplementation provoked a statistically significant increase in hydroxyl free radical generation in CSF treated with H(2)O(2). However, in a binary copper/iron containing Fenton system, iron catalytically activated copper. The chelator EDTA, which represents a model of physiological metal ligands, completely prevented copper's redox activity in CSF, while iron chelation led to a significant increase in hydroxyl radical generation, indicating that copper and iron do not only have diverse catalytic properties in the CSF but also that their redox activities are differently modulated by ligands. The application of DDC reduced hydroxyl radical generation in the CSF containing catalytically active metals (free Cu(2+) or Fe(3+)-EDTA complex). We conclude that chelators, such as DDC, are capable of preventing the prooxidative activity of both metals and may be suitable for reducing hydroxyl radical formation in certain pathophysiological settings.

Authors
Spasojević, I; Mojović, M; Stević, Z; Spasić, SD; Jones, DR; Morina, A; Spasić, MB
MLA Citation
Spasojević, I, Mojović, M, Stević, Z, Spasić, SD, Jones, DR, Morina, A, and Spasić, MB. "Bioavailability and catalytic properties of copper and iron for Fenton chemistry in human cerebrospinal fluid." Redox report : communications in free radical research 15.1 (January 2010): 29-35.
PMID
20196926
Source
epmc
Published In
Redox Report
Volume
15
Issue
1
Publish Date
2010
Start Page
29
End Page
35
DOI
10.1179/174329210x12650506623087

Comparative effects of thermosensitive doxorubicin-containing liposomes and hyperthermia in human and murine tumours.

PURPOSE: In previous reports, laboratory-made lysolecithin-containing thermosensitive liposome encapsulating doxorubicin (LTSL-DOX) showed potent anticancer effects in FaDu human squamous cell carcinoma. To further study the spectrum of LTSL-DOX activity, the efficacy of its commercial formulation was re-examined in FaDu and compared in HCT116, PC3, SKOV-3 and 4T07 cancer cell lines. Factors that may influence differences in HT-LTSL-DOX efficacy were also examined. METHODS: Anticancer effect was measured using standard growth delay methods. We measured doubling time and clonogenic survival after doxorubicin exposure in vitro, and interstitial pH and drug concentrations in vivo. RESULTS: In all five tumour types, HT-LTSL-DOX increased median tumour growth time compared with untreated controls (p < 0.0006) and HT alone (p < 0.01), and compared with LTSL-DOX alone in FaDu, PC-3 and HCT-116 (p < 0.0006). HT-LTSL-DOX yielded significantly higher drug concentrations than LTSL-DOX (p < 0.0001). FaDu was most sensitive (p < 0.0014) to doxorubicin (IC(50) = 90 nM) in vitro, compared to the other cell lines (IC(50) = 129-168 nM). Of the parameters tested for correlation with efficacy, only the correlation of in vitro doubling time and in vivo median growth time was significant (Pearson r = 0.98, p = 0.0035). Slower-growing SKOV-3 and PC-3 had the greatest numbers of complete regressions and longest tumour growth delays, which are clinically important parameters. CONCLUSIONS: These results strongly suggest that variations in anti-tumour effect of HT-LTSL-DOX are primarily related to in vitro doubling time. In the clinic, the rate of tumour progression must be considered in design of treatment regimens involving HT-LTSL-DOX.

Authors
Yarmolenko, PS; Zhao, Y; Landon, C; Spasojevic, I; Yuan, F; Needham, D; Viglianti, BL; Dewhirst, MW
MLA Citation
Yarmolenko, PS, Zhao, Y, Landon, C, Spasojevic, I, Yuan, F, Needham, D, Viglianti, BL, and Dewhirst, MW. "Comparative effects of thermosensitive doxorubicin-containing liposomes and hyperthermia in human and murine tumours." Int J Hyperthermia 26.5 (2010): 485-498.
PMID
20597627
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
26
Issue
5
Publish Date
2010
Start Page
485
End Page
498
DOI
10.3109/02656731003789284

High lipophilicity of meta Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase mimics compensates for their lower antioxidant potency and makes them as effective as ortho analogues in protecting superoxide dismutase-deficient Escherichia coli.

Lipophilicity/bioavailibility of Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase (SOD) mimics has a major impact on their in vivo ability to suppress oxidative stress. Meta isomers are less potent SOD mimics than ortho analogues but are 10-fold more lipophilic and more planar. Enhanced lipophilicity contributes to their higher accumulation in cytosol of SOD-deficient Escherichia coli, compensating for their lower potency; consequently, both isomers exert similar-to-identical protection of SOD-deficient E. coli. Thus meta isomers may be prospective therapeutics as are ortho porphyrins.

Authors
Kos, I; Benov, L; Spasojević, I; Rebouças, JS; Batinić-Haberle, I
MLA Citation
Kos, I, Benov, L, Spasojević, I, Rebouças, JS, and Batinić-Haberle, I. "High lipophilicity of meta Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase mimics compensates for their lower antioxidant potency and makes them as effective as ortho analogues in protecting superoxide dismutase-deficient Escherichia coli." J Med Chem 52.23 (December 10, 2009): 7868-7872.
PMID
19954250
Source
pubmed
Published In
Journal of Medicinal Chemistry
Volume
52
Issue
23
Publish Date
2009
Start Page
7868
End Page
7872
DOI
10.1021/jm900576g

Supraspinal inactivation of mitochondrial superoxide dismutase is a source of peroxynitrite in the development of morphine antinociceptive tolerance.

Effective treatment of chronic pain with morphine is limited by decreases in the drug's analgesic action with chronic administration (antinociceptive tolerance). Because opioids are mainstays of pain management, restoring their efficacy has great clinical importance. We have recently reported that formation of peroxynitrite (ONOO(-), PN) in the dorsal horn of the spinal cord plays a critical role in the development of morphine antinociceptive tolerance and have further documented that nitration and enzymatic inactivation of mitochondrial superoxide dismutase (MnSOD) at that site provides a source for this nitroxidative species. We now report for the first time that antinociceptive tolerance in mice is also associated with the inactivation of MnSOD at supraspinal sites. Inactivation of MnSOD led to nitroxidative stress as evidenced by increased levels of products of oxidative DNA damage and activation of the nuclear factor poly (ADP-ribose) polymerase in whole brain homogenates. Co-administration of morphine with potent Mn porphyrin-based peroxynitrite scavengers, Mn(III) 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP5+) and Mn(III) 5,10,15,20-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP5+) (1) restored the enzymatic activity of MnSOD, (2) attenuated PN-derived nitroxidative stress, and (3) blocked the development of morphine-induced antinociceptive tolerance. The more lipophilic analogue, MnTnHex-2-PyP5+ was able to cross the blood-brain barrier at higher levels than its lipophylic counterpart MnTE-2-PyP5+ and was about 30-fold more efficacious. Collectively, these data suggest that PN-mediated enzymatic inactivation of supraspinal MnSOD provides a source of nitroxidative stress, which in turn contributes to central sensitization associated with the development of morphine antinociceptive tolerance. These results support our general contention that PN-targeted therapeutics may have potential as adjuncts to opiates in pain management.

Authors
Doyle, T; Bryant, L; Batinic-Haberle, I; Little, J; Cuzzocrea, S; Masini, E; Spasojevic, I; Salvemini, D
MLA Citation
Doyle, T, Bryant, L, Batinic-Haberle, I, Little, J, Cuzzocrea, S, Masini, E, Spasojevic, I, and Salvemini, D. "Supraspinal inactivation of mitochondrial superoxide dismutase is a source of peroxynitrite in the development of morphine antinociceptive tolerance." Neuroscience 164.2 (December 1, 2009): 702-710.
PMID
19607887
Source
pubmed
Published In
Neuroscience
Volume
164
Issue
2
Publish Date
2009
Start Page
702
End Page
710
DOI
10.1016/j.neuroscience.2009.07.019

The SLCO1B1*5 genetic variant is associated with statin-induced side effects.

OBJECTIVES: We sought to identify single nucleotide polymorphisms associated with mild statin-induced side effects. BACKGROUND: Statin-induced side effects can interfere with therapy. Single nucleotide polymorphisms in cytochrome P450 enzymes impair statin metabolism; the reduced function SLCO1B1*5 allele impairs statin clearance and is associated with simvastatin-induced myopathy with creatine kinase (CK) elevation. METHODS: The STRENGTH (Statin Response Examined by Genetic Haplotype Markers) study was a pharmacogenetics study of statin efficacy and safety. Subjects (n = 509) were randomized to atorvastatin 10 mg, simvastatin 20 mg, or pravastatin 10 mg followed by 80 mg, 80 mg, and 40 mg, respectively. We defined a composite adverse event (CAE) as discontinuation for any side effect, myalgia, or CK >3x upper limit of normal during follow-up. We sequenced CYP2D6, CYP2C8, CYP2C9, CYP3A4, and SLCO1B1 and tested 7 reduced function alleles for association with the CAE. RESULTS: The CAE occurred in 99 subjects (54 discontinuations, 49 myalgias, and 9 CK elevations). Sex was associated with CAE (percent female in CAE vs. no CAE groups, 66% vs. 50%, p < 0.01). SLCO1B1*5 was associated with CAE (percent with > or = 1 allele in CAE vs. no CAE groups, 37% vs. 25%, p = 0.03) and those with CAE with no significant CK elevation (p < or = 0.03). Furthermore, there was evidence for a gene-dose effect (percent with CAE in those with 0, 1, or 2 alleles: 19%, 27%, and 50%, trend p = 0.01). Finally, the CAE risk appeared to be greatest in those carriers assigned to simvastatin. CONCLUSIONS: SLCO1B1*5 genotype and female sex were associated mild statin-induced side effects. These findings expand the results of a recent genome-wide association study of statin myopathy with CK >3x normal to milder, statin-induced, muscle side effects.

Authors
Voora, D; Shah, SH; Spasojevic, I; Ali, S; Reed, CR; Salisbury, BA; Ginsburg, GS
MLA Citation
Voora, D, Shah, SH, Spasojevic, I, Ali, S, Reed, CR, Salisbury, BA, and Ginsburg, GS. "The SLCO1B1*5 genetic variant is associated with statin-induced side effects." J Am Coll Cardiol 54.17 (October 20, 2009): 1609-1616.
PMID
19833260
Source
pubmed
Published In
Journal of the American College of Cardiology
Volume
54
Issue
17
Publish Date
2009
Start Page
1609
End Page
1616
DOI
10.1016/j.jacc.2009.04.053

Antioxidant properties of phenolics in Castanea sativa mill. Extracts

Using electron paramagnetic resonance (EPR) spectroscopy, antioxidant properties of chestnut extracts have been investigated as a source of phenolic compounds. In addition to their high antioxidant activities against hydroxyl and organic free (DPPH) radicals, phenolics showed to be potent protectors of membranes from lipid peroxidation. To the best of our knowledge, the ability of an antioxidant to overcome body's refractory response towards antioxidant supplementation has been examined for the first time. The water soluble extracts obtained from leaves, catkins, and outer brown peel of Castanea sativa Mill. showed high antioxidant activity in scavenging ·OH and DPPH radical. All extracts, except for sweet chestnut catkins, showed the ability to protect liposomes from peroxidation. Phenolic compounds, as active antioxidants, have the ability to enter and protect cell membranes from lipid peroxidation, thus overcoming the body's refractory response to the antioxidant supplements in the diet. It is shown that phenolics are easily accessible natural antioxidants that can be used as food supplements or for the treatment of pathophysiological conditions related to oxidative stress.

Authors
Živković, J; Zeković, Z; Mujić, I; Tumbas, V; Cvetković, D; Spasojević, I
MLA Citation
Živković, J, Zeković, Z, Mujić, I, Tumbas, V, Cvetković, D, and Spasojević, I. "Antioxidant properties of phenolics in Castanea sativa mill. Extracts." Food Technology and Biotechnology 47.4 (October 1, 2009): 421-427.
Source
scopus
Published In
Food Technology and Biotechnology
Volume
47
Issue
4
Publish Date
2009
Start Page
421
End Page
427

Antiangiogenic action of redox-modulating Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), via suppression of oxidative stress in a mouse model of breast tumor.

MnTE-2-PyP(5+) is a potent catalytic scavenger of reactive oxygen and nitrogen species, primarily superoxide and peroxynitrite. It therefore not only attenuates primary oxidative damage, but was found to modulate redox-based signaling pathways (HIF-1alpha, NF-kappaB, SP-1, and AP-1) and thus, in turn, secondary oxidative injury also. Cancer has been widely considered an oxidative stress condition. The goal of this study was to prove if and why a catalytic SOD mimic/peroxynitrite scavenger would exert anti-cancer effects, i.e., to evaluate whether the attenuation of the oxidative stress by MnTE-2-PyP(5+) could suppress tumor growth in a 4T1 mouse breast tumor model. Tumor cells were implanted into Balb/C mouse flanks. Three groups of mice (n=25) were studied: control (PBS) and 2 and 15 mg/kg/day of MnTE-2-PyP(5+) given subcutaneously twice daily starting when the tumors averaged 200 mm(3) (until they reached approximately 5-fold the initial volume). Intratumoral hypoxia (pimonidazole, carbonic anhydrase), HIF-1alpha, VEGF, proliferating capillary index (CD105), microvessel density (CD31), protein nitration, DNA oxidation (8-OHdG), NADPH oxidase (Nox-4), apoptosis (CD31), macrophage infiltration (CD68), and tumor drug levels were assessed. With 2 mg/kg/day a trend toward tumor growth delay was observed, and a significant trend was observed with 15 mg/kg/day. The 7.5-fold increase in drug dose was accompanied by a similar (6-fold) increase in tumor drug levels. Oxidative stress was largely attenuated as observed through the decreased levels of DNA damage, protein 3-nitrotyrosine, macrophage infiltration, and NADPH oxidase. Further, hypoxia was significantly decreased as were the levels of HIF-1alpha and VEGF. Consequently, suppression of angiogenesis was observed; both the microvessel density and the endothelial cell proliferation were markedly decreased. Our study indicates for the first time that MnTE-2-PyP(5+) has anti-cancer activity in its own right. The anti-cancer activity via HIF/VEGF pathways probably arises from the impact of the drug on the oxidative stress. Therefore, the catalytic scavenging of ROS/RNS by antioxidants, which in turn suppresses cellular transcriptional activity, could be an appropriate strategy for anti-cancer therapy. Enhancement of the anti-cancer effects may be achieved by optimizing the dosing regime, utilizing more bioavailable Mn porphyrins (MnP), and combining MnP treatment with irradiation, hyperthermia, and chemotherapy. Mn porphyrins may be advantageous compared to other anti-cancer drugs, owing to their radioprotection of normal tissue and the ability to afford pain management in cancer patients via prevention of chronic morphine tolerance.

Authors
Rabbani, ZN; Spasojevic, I; Zhang, X; Moeller, BJ; Haberle, S; Vasquez-Vivar, J; Dewhirst, MW; Vujaskovic, Z; Batinic-Haberle, I
MLA Citation
Rabbani, ZN, Spasojevic, I, Zhang, X, Moeller, BJ, Haberle, S, Vasquez-Vivar, J, Dewhirst, MW, Vujaskovic, Z, and Batinic-Haberle, I. "Antiangiogenic action of redox-modulating Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), via suppression of oxidative stress in a mouse model of breast tumor." Free Radic Biol Med 47.7 (October 1, 2009): 992-1004.
PMID
19591920
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
7
Publish Date
2009
Start Page
992
End Page
1004
DOI
10.1016/j.freeradbiomed.2009.07.001

Protective role of fructose in the metabolism of astroglial C6 cells exposed to hydrogen peroxide.

Astroglial cells represent the main line of defence against oxidative damage related to neurodegeneration. Therefore, protection of astroglia from an excess of reactive oxygen species could represent an important target of the treatment of such conditions. The aim of our study was to compare the abilities of glucose and fructose, the two monosaccharides used in diet and infusion, to protect C6 cells from hydrogen peroxide (H(2)O(2))-mediated oxidative stress. It was observed using confocal microscopy with fluorescent labels and the MTT test that fructose prevents changes of oxidative status of the cells exposed to H(2)O(2) and preserves their viability. Even more pronounced protective effects were observed for fructose 1,6-bis(phosphate). We propose that fructose and its intracellular forms prevent H(2)O(2) from participating in the Fenton reaction via iron sequestration. As fructose and fructose 1,6-bis(phosphate) are able to pass the blood-brain barrier, they could provide antioxidative protection of nervous tissue in vivo. So, in contrast to the well-known negative effects of frequent consumption of fructose under physiological conditions, acute infusion or ingestion of fructose or fructose 1,6-bis(phosphate) could be of benefit in the cytoprotective therapy of neurodegenerative disorders related to oxidative stress.

Authors
Spasojević, I; Bajić, A; Jovanović, K; Spasić, M; Andjus, P
MLA Citation
Spasojević, I, Bajić, A, Jovanović, K, Spasić, M, and Andjus, P. "Protective role of fructose in the metabolism of astroglial C6 cells exposed to hydrogen peroxide." Carbohydrate research 344.13 (September 2009): 1676-1681.
PMID
19591975
Source
epmc
Published In
Carbohydrate Research
Volume
344
Issue
13
Publish Date
2009
Start Page
1676
End Page
1681
DOI
10.1016/j.carres.2009.05.023

Potential role of hydrogen peroxide and melanin in the cold hardiness of Ostrinia nubilalis (Lepidoptera: Pyralidae)

Authors
KOJIC, D; SPASOJEVIC, I; MOJOVIC, M; BLAGOJEVIC, D; WORLAND, MR; GRUBOR-LAJSIC, G; SPASIC, MB
MLA Citation
KOJIC, D, SPASOJEVIC, I, MOJOVIC, M, BLAGOJEVIC, D, WORLAND, MR, GRUBOR-LAJSIC, G, and SPASIC, MB. "Potential role of hydrogen peroxide and melanin in the cold hardiness of Ostrinia nubilalis (Lepidoptera: Pyralidae)." European Journal of Entomology 106.3 (July 24, 2009): 451-454.
Source
crossref
Published In
European journal of entomology
Volume
106
Issue
3
Publish Date
2009
Start Page
451
End Page
454
DOI
10.14411/eje.2009.056

Lipophilicity of potent porphyrin-based antioxidants: comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins.

Mn(III) N-alkylpyridylporphyrins are among the most potent known SOD mimics and catalytic peroxynitrite scavengers and modulators of redox-based cellular transcriptional activity. In addition to their intrinsic antioxidant capacity, bioavailability plays a major role in their in vivo efficacy. Although of identical antioxidant capacity, lipophilic MnTnHex-2-PyP is up to 120-fold more efficient in reducing oxidative stress injuries than hydrophilic MnTE-2-PyP. Owing to limitations of an analytical nature, porphyrin lipophilicity has been often estimated by the thin-layer chromatographic R(f) parameter, instead of the standard n-octanol/water partition coefficient, P(OW). Herein we used a new methodological approach to finally describe the MnP lipophilicity, using the conventional log P(OW) means, for a series of biologically active ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins. Three new porphyrins (MnTnBu-3-PyP, MnTnHex-3-PyP, and MnTnHep-2-PyP) were synthesized to strengthen the conclusions. The log P(OW) was linearly related to R(f) and to the number of carbons in the alkyl chain (n(C)) for both isomer series, the meta isomers being 10-fold more lipophilic than the analogous ortho porphyrins. Increasing the length of the alkyl chain by one carbon atom increases the log P(OW) value approximately 1 log unit with both isomers. Dramatic approximately 4 and approximately 5 orders of magnitude increases in the lipophilicity of the ortho isomers, by extending the pyridyl alkyl chains from two (MnTE-2-PyP, log P(OW)=-6.89) to six (MnTnHex-2-PyP, log P(OW)=-2.76) and eight carbon atoms (MnTnOct-2-PyP, log P(OW)=-1.24), parallels the increased efficacy in several oxidative-stress injury models, particularly those of the central nervous system, in which transport across the blood-brain barrier is critical. Although meta isomers are only slightly less potent SOD mimics and antioxidants than their ortho analogues, their higher lipophilicity and smaller bulkiness may lead to a higher cellular uptake and overall similar effectiveness in vivo.

Authors
Kos, I; Rebouças, JS; DeFreitas-Silva, G; Salvemini, D; Vujaskovic, Z; Dewhirst, MW; Spasojević, I; Batinić-Haberle, I
MLA Citation
Kos, I, Rebouças, JS, DeFreitas-Silva, G, Salvemini, D, Vujaskovic, Z, Dewhirst, MW, Spasojević, I, and Batinić-Haberle, I. "Lipophilicity of potent porphyrin-based antioxidants: comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins." Free Radic Biol Med 47.1 (July 1, 2009): 72-78.
PMID
19361553
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
1
Publish Date
2009
Start Page
72
End Page
78
DOI
10.1016/j.freeradbiomed.2009.04.002

EPR Spin-Trapping and Spin-Probing Spectroscopy in Assessing Antioxidant Properties: Example on Extracts of Catkin, Leaves, and Spiny Burs of Castanea sativa

Authors
Živković, J; Zeković, Z; Mujić, I; Gođevac, D; Mojović, M; Mujić, A; Spasojević, I
MLA Citation
Živković, J, Zeković, Z, Mujić, I, Gođevac, D, Mojović, M, Mujić, A, and Spasojević, I. "EPR Spin-Trapping and Spin-Probing Spectroscopy in Assessing Antioxidant Properties: Example on Extracts of Catkin, Leaves, and Spiny Burs of Castanea sativa." Food Biophysics 4.2 (June 2009): 126-133.
Source
crossref
Published In
Food Biophysics
Volume
4
Issue
2
Publish Date
2009
Start Page
126
End Page
133
DOI
10.1007/s11483-009-9109-8

Optimizing melphalan pharmacokinetics in regional melanoma therapy: does correcting for ideal body weight alter regional response or toxicity?

BACKGROUND: This study aims to determine what effect correcting melphalan dosing for ideal body weight (IBW) has on toxicity and response in isolated limb infusion (ILI) in patients with advanced extremity melanoma. METHODS: This was an open observational study examining whether correcting the melphalan dose for IBW will influence response and toxicity in patients undergoing ILI for advanced extremity melanoma in 41 patients undergoing 42 procedures (13 without correction for IBW; and 29 with correction for IBW). Melphalan pharmacokinetics, limb toxicity, serologic toxicity, and response at 3 months were compared. RESULTS: The corrected group had a lower estimated limb volume (V (esti)) to melphalan volume at steady state (V (ss)) (P < .0001) ratio as well as lower incidence of grade > or =3 regional toxicity, serologic toxicity, and compartment syndrome (P = .0249, P = .027, P = .02). There was a positive correlation of V (esti)/V (ss) to toxicity (P = .0127, r = .382). No significant difference in response (P = .3609) between the groups was found, although there was a trend of association between V (esti)/V (ss) and response (P = .051, r = .3383). CONCLUSIONS: Correcting for IBW in ILI lowers toxicity without significantly altering response rates.

Authors
McMahon, N; Cheng, TY; Beasley, GM; Spasojevic, I; Petros, W; Augustine, CK; Zipfel, P; Padussis, JC; Sanders, G; Tyler, DS
MLA Citation
McMahon, N, Cheng, TY, Beasley, GM, Spasojevic, I, Petros, W, Augustine, CK, Zipfel, P, Padussis, JC, Sanders, G, and Tyler, DS. "Optimizing melphalan pharmacokinetics in regional melanoma therapy: does correcting for ideal body weight alter regional response or toxicity?." Ann Surg Oncol 16.4 (April 2009): 953-961.
PMID
19184236
Source
pubmed
Published In
Annals of Surgical Oncology
Volume
16
Issue
4
Publish Date
2009
Start Page
953
End Page
961
DOI
10.1245/s10434-008-0288-1

Effect of lipophilicity of Mn (III) ortho N-alkylpyridyl- and diortho N, N'-diethylimidazolylporphyrins in two in-vitro models of oxygen and glucose deprivation-induced neuronal death.

In vivo investigations have confirmed the beneficial effects of hydrophilic, cationic Mn(III) porphyrin-based catalytic antioxidants in different models of oxidative stress. Using a cell culture model of rat mixed neuronal/glial cells, this study investigated the effect of MnTnOct-2-PyP5+ on oxygen and glucose deprivation (OGD)-induced cell death as compared to the effects of widely studied hydrophilic analogues MnTE-2-PyP5+ and MnTDE-2-ImP5+ and a standard compound, dizocilpine (MK-801). It was hypothesized that the octylpyridylporphyrin, MnTnOct-2-PyP5+, a lipophilic but equally potent antioxidant as the other two porphyrins, would be more efficacious in reducing OGD-induced cell death due to its higher bioavailability. Cell death was evaluated at 24 h using lactate dehydrogenase (LDH) release and propidium iodide staining. At concentrations from 3-100 microM, all three porphyrins reduced cell death as compared to cultures exposed to OGD alone, the effects depending upon the concentrations and type of treatment. To assess the effect of lipophilicity the additional experiments were performed using submicromolar concentrations of MnTnOct-2-PyP5+ in an organotypic hippocampal slice model of OGD with propidium iodide and Sytox staining. When compared to oxygen and glucose deprivation alone, concentrations of MnTnOct-2-PyP5+ as low as 0.01 microM significantly (p<0.001; power 1.0) reduced neuronal cells similar to control. This is the first in vitro study on the mammalian cells which indicates that MnTnOct-2-PyP5+ is up to 3000-fold more efficacious than equally potent hydrophilic analogues, due entirely to its increased bioavailability. Such remarkable increase in efficacy parallels 5.7-orders of magnitude increase in lipophilicity of MnTnOct-2-PyP5+ (log P=-0.77) when compared to MnTE-2-PyP5+ (log POW=-6.43), POW being partition coefficient between n-octanol and water.

Authors
Wise-Faberowski, L; Warner, DS; Spasojevic, I; Batinic-Haberle, I
MLA Citation
Wise-Faberowski, L, Warner, DS, Spasojevic, I, and Batinic-Haberle, I. "Effect of lipophilicity of Mn (III) ortho N-alkylpyridyl- and diortho N, N'-diethylimidazolylporphyrins in two in-vitro models of oxygen and glucose deprivation-induced neuronal death." Free Radic Res 43.4 (April 2009): 329-339.
PMID
19259881
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
43
Issue
4
Publish Date
2009
Start Page
329
End Page
339
DOI
10.1080/10715760902736283

Lipophilicity is a critical parameter that dominates the efficacy of metalloporphyrins in blocking the development of morphine antinociceptive tolerance through peroxynitrite-mediated pathways.

Severe pain syndromes reduce the quality of life of patients with inflammatory and neoplastic diseases, partly because reduced analgesic effectiveness with chronic opiate therapy (i.e., tolerance) leads to escalating doses and distressing side effects. Peroxynitrite-mediated nitroxidative stress in the dorsal horn of the spinal cord plays a critical role in the induction and development of antinociceptive tolerance to morphine. This provides a valid pharmacological basis for developing peroxynitrite scavengers as potent adjuncts to opiates in the management of pain. The cationic Mn(III) ortho-N-alkylpyridylporphyrins MnTE-2-PyP(5+) and MnTnHex-2-PyP(5+) are among the most potent peroxynitrite scavengers, with nearly identical scavenging rate constants (approximately 10(7) M(-1) s(-1)). Yet, MnTnHex-2-PyP(5+) is significantly more lipophilic and more bioavailable and, in turn, was 30-fold more effective in blocking the development of morphine antinociceptive tolerance than MnTE-2-PyP(5+) using the hot-plate test in a well-characterized murine model. The hydrophilic MnTE-2-PyP(5+) and the lipophilic MnTnHex-2-PyP(5+) were 10- and 300-fold, respectively, more effective in inhibiting morphine tolerance than the hydrophilic Fe(III) porphyrin FeTM-4-PyP(5+). Both Mn porphyrins decreased levels of TNF-alpha, IL-1 beta, and IL-6 to normal values. Neither of them affected acute morphine antinociceptive effects nor caused motor function impairment. Also neither was able to reverse already established morphine tolerance. We have recently shown that the anionic porphyrin Mn(III) tetrakis(4-carboxylatophenyl)porphyrin is selective in removing ONOO(-) over O(2)(-), but at approximately 2 orders of magnitude lower efficacy than MnTE-2-PyP(5+) and MnTnHex-2-PyP(5+), which in turn parallels up to 100-fold lower ability to reverse morphine tolerance. These data (1) support the role of peroxynitrite rather than superoxide as a major mechanism in blocking the development of morphine tolerance and (2) show that lipophilicity is a critical parameter in enhancing the potency of such novel peroxynitrite scavengers.

Authors
Batinić-Haberle, I; Ndengele, MM; Cuzzocrea, S; Rebouças, JS; Spasojević, I; Salvemini, D
MLA Citation
Batinić-Haberle, I, Ndengele, MM, Cuzzocrea, S, Rebouças, JS, Spasojević, I, and Salvemini, D. "Lipophilicity is a critical parameter that dominates the efficacy of metalloporphyrins in blocking the development of morphine antinociceptive tolerance through peroxynitrite-mediated pathways." Free Radic Biol Med 46.2 (January 15, 2009): 212-219.
PMID
18983908
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
46
Issue
2
Publish Date
2009
Start Page
212
End Page
219
DOI
10.1016/j.freeradbiomed.2008.09.037

Pure MnTBAP selectively scavenges peroxynitrite over superoxide: comparison of pure and commercial MnTBAP samples to MnTE-2-PyP in two models of oxidative stress injury, an SOD-specific Escherichia coli model and carrageenan-induced pleurisy.

MnTBAP is often referred to as an SOD mimic in numerous models of oxidative stress. We have recently reported that pure MnTBAP does not dismute superoxide, but commercial or poorly purified samples are able to perform O2.- dismutation with low-to-moderate efficacy via non-innocent Mn-containing impurities. Herein, we show that neither commercial nor pure MnTBAP could substitute for SOD enzyme in a SOD-deficient Escherichia coli model, whereas MnTE-2-PyP-treated SOD-deficient E. coli grew as well as a wild-type strain. This SOD-specific system indicates that MnTBAP does not act as an SOD mimic in vivo. In another model, carrageenan-induced pleurisy in mice, inflammation was evidenced by increased pleural fluid exudate and neutrophil infiltration and activation: these events were blocked by 0.3 mg/kg MnTE-2-PyP and, to a slightly lesser extent, by 10 mg/kg of either MnTBAP. Also, 3-nitrotyrosine formation, an indication of peroxynitrite existence in vivo, was blocked by both compounds; again MnTE-2-PyP was 33-fold more effective. Pleurisy model data indicate that MnTBAP exerts some protective actions in common with MnTE-2-PyP, which are not O2.- related and can be fully rationalized if one considers that the common biological role shared by MnTBAP and MnTE-2-PyP is related to their reduction of peroxynitrite and carbonate radical, the latter arising from ONOOCO2 adduct. The log kcat (O2.-) value for MnTBAP is estimated to be about 3.16, which is approximately 5 and approximately 6 orders of magnitude smaller than the SOD activities of the potent SOD mimic MnTE-2-PyP and Cu,Zn-SOD, respectively. This very low value indicates that MnTBAP is too inefficient at dismuting superoxide to be of any biological impact, which was confirmed in the SOD-deficient E. coli model. The peroxynitrite scavenging ability of MnTBAP, however, is only approximately 2.5 orders of magnitude smaller than that of MnTE-2-PyP and is not significantly affected by the presence of the SOD-active impurities in the commercial MnTBAP sample (log k red (ONOO-) = 5.06 for pure and 4.97 for commercial sample). The reduction of carbonate radical is equally fast with MnTBAP and MnTE-2-PyP. The dose of MnTBAP required to yield oxidative stress protection and block nitrotyrosine formation in the pleurisy model is > 1.5 orders of magnitude higher than that of MnTE-2-PyP, which could be related to the lower ability of MnTBAP to scavenge peroxynitrite. The slightly better protection observed with the commercial MnTBAP sample (relative to the pure MnTBAP) could arise from its impurities, which, by scavenging O2.-, reduce consequently the overall peroxynitrite and secondary ROS/RNS levels. These observations have profound biological repercussions as they may suggest that the effect of MnTBAP observed in numerous studies may conceivably relate to peroxynitrite scavenging. Moreover, provided that pure MnTBAP is unable to dismute superoxide at any significant extent, but is able to partially scavenge peroxynitrite and carbonate radical, this compound may prove valuable in distinguishing ONOO-/CO3.- from O2.- pathways.

Authors
Batinić-Haberle, I; Cuzzocrea, S; Rebouças, JS; Ferrer-Sueta, G; Mazzon, E; Di Paola, R; Radi, R; Spasojević, I; Benov, L; Salvemini, D
MLA Citation
Batinić-Haberle, I, Cuzzocrea, S, Rebouças, JS, Ferrer-Sueta, G, Mazzon, E, Di Paola, R, Radi, R, Spasojević, I, Benov, L, and Salvemini, D. "Pure MnTBAP selectively scavenges peroxynitrite over superoxide: comparison of pure and commercial MnTBAP samples to MnTE-2-PyP in two models of oxidative stress injury, an SOD-specific Escherichia coli model and carrageenan-induced pleurisy." Free Radic Biol Med 46.2 (January 15, 2009): 192-201.
PMID
19007878
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
46
Issue
2
Publish Date
2009
Start Page
192
End Page
201
DOI
10.1016/j.freeradbiomed.2008.09.042

Diethyldithiocarbamate potentiates the effects of protamine sulphate in the isolated rat uterus.

Protamine sulphate causes potassium ion channel-mediated relaxation of spontaneous and calcium ion-induced contractions of the isolated rat uterus. Diethyldithiocarbamate (DDC) potentiated the effect of protamine sulphate. A mechanism for DDC's action was postulated on the basis of its interactions with divalent iron ions and Cu,Zn-SOD. DDC chelates divalent iron ions creating DDC-iron (Fe-DDC) complexes. Fe-DDC forms stable NO-Fe-DDC(2) complexes by NO scavenging and de-nitrosylation processes, which in combination with DDC (5 mM) provoke inhibition of Cu,Zn-SOD resulting in specific oxidative conditions culminating in potassium ion channel opening, membrane hyperpolarisation, inhibition of calcium ion influx and subsequent muscle relaxation. As Fe-DDC and NO-Fe-DDC(2) complexes exclude divalent iron ions from participating in the hydroxyl radical generating Fenton reaction, DDC can also prevent iron-related pathophysiological manifestations. Such permissive roles of DDC open the possibility for application of its pharmacological form (disulfiram) to a wider spectrum of pathophysiological conditions related to smooth muscles.

Authors
Orescanin-Dusić, Z; Milovanović, S; Blagojević, D; Nikolić-Kokić, A; Radojicić, R; Spasojević, I; Spasić, M
MLA Citation
Orescanin-Dusić, Z, Milovanović, S, Blagojević, D, Nikolić-Kokić, A, Radojicić, R, Spasojević, I, and Spasić, M. "Diethyldithiocarbamate potentiates the effects of protamine sulphate in the isolated rat uterus." Redox report : communications in free radical research 14.2 (January 2009): 48-54.
PMID
19389271
Source
epmc
Published In
Redox Report
Volume
14
Issue
2
Publish Date
2009
Start Page
48
End Page
54
DOI
10.1179/135100009x392476

Antioxidative defense enzymes in placenta protect placenta and fetus in inherited thrombophilia from hydrogen peroxide.

Our aim was to investigate the activities of antioxidative defense enzymes in the placenta, fetal blood and amnion fluid in inherited thrombophilia. Thrombophilia was associated with nearly threefold increase of activity (p < 0.001) of the placental catalase (81.1 +/- 20.6 U/mg of proteins in controls and 270.0 +/- 69.9 U/mg in thrombophilic subjects), glutathione (GSH) peroxidase (C: 20.2 +/- 10.1 U/mg; T: 60.0 +/- 15.5 U/mg), and GSH reductase (C: 28.9 +/- 5.6 U/mg; T: 72.7 +/- 23.0 U/mg). The placental activities of superoxide dismutating enzymes--MnSOD and CuZnSOD, did not differ in controls and thrombophilia. Likewise, the activities of catalase and SOD in the fetal blood, and the level of ascorbyl radical which represents a marker of oxidative status of amniotic fluid, were similar in controls and thrombophilic subjects. From this we concluded that in thrombophilia, placental tissue is exposed to H(2)O(2)-mediated oxidative stress, which could be initiated by pro-thrombic conditions in maternal blood. Increased activity of placental H(2)O(2)-removing enzymes protects fetus and mother during pregnancy, but may increase the risk of postpartum thrombosis.

Authors
Pristov, JB; Spasojevic, I; Mikovic, Z; Mandic, V; Cerovic, N; Spasic, M
MLA Citation
Pristov, JB, Spasojevic, I, Mikovic, Z, Mandic, V, Cerovic, N, and Spasic, M. "Antioxidative defense enzymes in placenta protect placenta and fetus in inherited thrombophilia from hydrogen peroxide." Oxidative medicine and cellular longevity 2.1 (January 2009): 14-18.
PMID
20046640
Source
epmc
Published In
Oxidative Medicine and Cellular Longevity
Volume
2
Issue
1
Publish Date
2009
Start Page
14
End Page
18
DOI
10.4161/oxim.2.1.7705

Relevance of the capacity of phosphorylated fructose to scavenge the hydroxyl radical.

The hydroxyl radical (*OH) has detrimental biological activity due to its very high reactivity. Our experiments were designed to determine the effects of equimolar concentrations of glucose, fructose and mannitol and three phosphorylated forms of fructose (fructose-1-phosphate (F1P); fructose-6-phosphate (F6P); and fructose-1,6-bis(phosphate) (F16BP)) on *OH radical production via the Fenton reaction. EPR spectroscopy using spin-trap DEPMPO was applied to detect radical production. We found that the percentage inhibition of *OH radical formation decreased in the order F16BP>F1P>F6P>fructose>mannitol=glucose. As ketoses can sequester redox-active iron thus preventing the Fenton reaction, the Haber-Weiss-like system was also employed to generate *OH, so that the effect of iron sequestration could be distinguished from direct *OH radical scavenging. In the latter system, the rank order of *OH scavenging activity was F16BP>F1P>F6P>fructose=mannitol=glucose. Our results clearly demonstrate that intracellular phosphorylated forms of fructose have more scavenging properties than fructose or glucose, leading us to conclude that the acute administration of fructose could overcome the body's reaction to exogenous antioxidants during appropriate therapy in certain pathophysiological conditions related to oxidative stress, such as sepsis, neurodegenerative diseases, atherosclerosis, malignancy, and some complications of pregnancy.

Authors
Spasojević, I; Mojović, M; Blagojević, D; Spasić, SD; Jones, DR; Nikolić-Kokić, A; Spasić, MB
MLA Citation
Spasojević, I, Mojović, M, Blagojević, D, Spasić, SD, Jones, DR, Nikolić-Kokić, A, and Spasić, MB. "Relevance of the capacity of phosphorylated fructose to scavenge the hydroxyl radical." Carbohydrate research 344.1 (January 2009): 80-84.
PMID
18947823
Source
epmc
Published In
Carbohydrate Research
Volume
344
Issue
1
Publish Date
2009
Start Page
80
End Page
84
DOI
10.1016/j.carres.2008.09.025

Decreased oxygen transfer capacity of erythrocytes as a cause of 5-fluorouracil related ischemia.

Various mechanisms have been proposed to account for chemotherapy related ischemia, but none of them can explain the available clinical data. In order to explore the possibility that the decreased ability of erythrocytes to deliver oxygen to the heart could be responsible for cardiotoxicity, we have performed an ex vivo and in vivo study of the effects of cisplatin/5-FU on erythrocytes, using a variety of biophysical techniques. Combining EPR and microscopy it was concluded that both cardiotoxic 5-FU and non-cardiotoxic cisplatin have similar effects on the erythrocyte membrane, thus eliminating those changes as a potential source of cardiotoxicity. On the contrary, 31P-NMR and polarography showed that the effects of these cytostatics on the intracellular milieu differ significantly. 5-FU provoked a pronounced decrease of the O2 level in blood and affected the metabolism of phosphate compounds, while cisplatin had no such effects. When combined these two drugs showed synergistic effects, which matches the higher frequency of cardiotoxicity of the combination relative to the sole application of 5-FU. Preliminary results acquired on blood of patients receiving cisplatin/5-FU therapy verified observations obtained ex vivo. These results open a possibility of applying NMR in preclinical trials of new drugs in order to predict their ischemic potential.

Authors
Spasojević, I; Jelić, S; Zakrzewska, J; Bacić, G
MLA Citation
Spasojević, I, Jelić, S, Zakrzewska, J, and Bacić, G. "Decreased oxygen transfer capacity of erythrocytes as a cause of 5-fluorouracil related ischemia." Molecules (Basel, Switzerland) 14.1 (January 2009): 53-67.
PMID
19127237
Source
epmc
Published In
Molecules (Basel, Switzerland)
Volume
14
Issue
1
Publish Date
2009
Start Page
53
End Page
67
DOI
10.3390/molecules14010053

Quality of potent Mn porphyrin-based SOD mimics and peroxynitrite scavengers for pre-clinical mechanistic/therapeutic purposes.

Cationic Mn porphyrins are among the most potent SOD mimics and peroxynitrite scavengers. They have been widely and successfully used in different models of oxidative stress and are either progressing towards or are in phase I of clinical trials. The most frequently used compounds are Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+) or AEOL10113), its methyl analogue (MnTM-2-PyP(5+) or AEOL10112), and Mn(III) meso-tetrakis(4-benzoic acid)porphyrin (MnTBAP). A great discrepancy between the in vivo data obtained with Calbiochem preparations and those of authentic MnTE-2-PyP(5+) and MnTM-2-PyP(5+) samples were recently observed. Surprisingly, the commercial samples were invariably of poor identity and consisted of mixtures of nearly equal contributions of non-alkylated, mono-, di-, tri- and tetraalkylated porphyrins, lacking thus the major structural entity that determines their antioxidant potency, i.e., the four positively charged orthoN-alkylpyridyl groups that afford thermodynamic tuning of the active site and electrostatic guidance of anionic superoxide and peroxynitrite species toward the metal center. The MnTE-2-PyP(5+) and MnTM-2-PyP(5+) compounds were not even the major species in the commercial samples sold as "MnTE-2-PyP" and "MnTM-2-PyP", respectively. While we have already reported the insufficient impurity of the MnTBAP samples from Alexis and other suppliers, in one more recent lot the situation is dramatic, as 25% of the sample was not MnTBAP, but metal-free ligand, H(2)TBAP. The (unintentional) use of the Mn porphyrins of low quality compromises therapeutic and/or mechanistic conclusions. Simple techniques, which include thin-layer chromatography, electrospray-mass spectrometry, UV-vis spectroscopy, and electrochemistry described here could be used routinely to check the overall quality of Mn porphyrins in order to avoid misleading conclusions and waste of valuable resources (animals, compounds, time, manpower).

Authors
Rebouças, JS; Spasojević, I; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, and Batinić-Haberle, I. "Quality of potent Mn porphyrin-based SOD mimics and peroxynitrite scavengers for pre-clinical mechanistic/therapeutic purposes." J Pharm Biomed Anal 48.3 (November 4, 2008): 1046-1049.
PMID
18804338
Source
pubmed
Published In
Journal of Pharmaceutical and Biomedical Analysis
Volume
48
Issue
3
Publish Date
2008
Start Page
1046
End Page
1049
DOI
10.1016/j.jpba.2008.08.005

Pharmacokinetics of the potent redox-modulating manganese porphyrin, MnTE-2-PyP(5+), in plasma and major organs of B6C3F1 mice.

Mn(III) tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), a potent catalytic superoxide and peroxynitrite scavenger, has been beneficial in several oxidative stress-related diseases thus far examined. Pharmacokinetic studies are essential for the better assessment of the therapeutic potential of MnTE-2-PyP(5+) and similar compounds, as well as for the modulation of their bioavailability and toxicity. Despite high hydrophilicity, this drug entered mitochondria after a single 10 mg/kg intraperitoneal injection at levels high enough (5.1 muM; 2.95 ng/mg protein) to protect against superoxide/peroxynitrite damage. Utilizing the same analytical approach, which involves the reduction of MnTE-2-PyP(5+) followed by the exchange of Mn(2+) with Zn(2+) and HPLC/fluorescence detection of ZnTE-2-PyP(4+), we measured levels of MnTE-2-PyP(5+) in mouse plasma, liver, kidney, lung, heart, spleen, and brain over a period of 7 days after a single intraperitoneal injection of 10 mg/kg. Two B6C3F1 female mice per time point were used. The pharmacokinetic profile in plasma and organs was complex; thus a noncompartmental approach was utilized to calculate the area under the curve, c(max), t(max), and drug elimination half-time (t(1/2)). In terms of levels of MnTE-2-PyP(5+) found, the organs can be classified into three distinct groups: (1) high levels (kidney, liver, and spleen), (2) moderate levels (lung and heart), and (3) low levels (brain). The maximal levels in plasma, kidney, spleen, lung, and heart are reached within 45 min, whereas in the case of liver a prolonged absorption phase was observed, with the maximal concentration reached at 8 h. Moreover, accumulation of the drug in brain continued beyond the time of the experiment (7 days) and is likely to be driven by the presence of negatively charged phospholipids. For tissues other than brain, a slow elimination phase (single exponential decay, t(1/2)=60 to 135 h) was observed. The calculated pharmacokinetic parameters will be used to design optimal dosing regimens in future preclinical studies utilizing this and similar compounds.

Authors
Spasojević, I; Chen, Y; Noel, TJ; Fan, P; Zhang, L; Rebouças, JS; St Clair, DK; Batinić-Haberle, I
MLA Citation
Spasojević, I, Chen, Y, Noel, TJ, Fan, P, Zhang, L, Rebouças, JS, St Clair, DK, and Batinić-Haberle, I. "Pharmacokinetics of the potent redox-modulating manganese porphyrin, MnTE-2-PyP(5+), in plasma and major organs of B6C3F1 mice." Free Radic Biol Med 45.7 (October 1, 2008): 943-949.
PMID
18598757
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
45
Issue
7
Publish Date
2008
Start Page
943
End Page
949
DOI
10.1016/j.freeradbiomed.2008.05.015

SOD-like activity of Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-3-yl)porphyrin equals that of the enzyme itself.

Mn porphyrins are among the most efficient SOD mimics with potency approaching that of SOD enzymes. The most potent ones, Mn(III) N-alkylpyridylporphyrins bear positive charges in a close proximity to the metal site, affording thermodynamic and kinetic facilitation for the reaction with negatively charged superoxide. The addition of electron-withdrawing bromines onto beta-pyrrolic positions dramatically improves thermodynamic facilitation for the O2*- dismutation. We have previously characterized the para isomer, Mn(II)Br(8)TM-4-PyP(4+) [Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-4-yl)porphyrin]. Herein we fully characterized its meta analogue, Mn(II)Br(8)TM-3-PyP(4+) with respect to UV/vis spectroscopy, electron spray mass spectrometry, electrochemistry, O2*- dismutation, metal-ligand stability, and the ability to protect SOD-deficient Escherichia coli in comparison with its para analogue. The increased electron-deficiency of the metal center stabilizes Mn in its +2 oxidation state. The metal-centered Mn(III)/Mn(II) reduction potential, E((1/2))=+468 mV vs NHE, is increased by 416 mV with respect to non-brominated analogue, Mn(III)TM-3-PyP(5+) and is only 12 mV less positive than for para isomer. Yet, the complex is significantly more stable towards the loss of metal than its para analogue. As expected, based on the structure-activity relationships, an increase in E((1/2)) results in a higher catalytic rate constant for the O2*- dismutation, log k(cat)> or =8.85; 1.5-fold increase with respect to the para isomer. The IC(50) was calculated to be < or =3.7 nM. Manipulation of the electron-deficiency of a cationic porphyrin resulted, therefore, in the highest k(cat) ever reported for a metalloporphyrin, being essentially identical to the k(cat) of superoxide dismutases (log k(cat)=8.84-9.30). The positive kinetic salt effect points to the unexpected, unique and first time recorded behavior of Mn beta-octabrominated porphyrins when compared to other Mn porphyrins studied thus far. When species of opposing charges react, the increase in ionic strength invariably results in the decreased rate constant; with brominated porphyrins the opposite was found to be true. The effect is 3.5-fold greater with meta than with para isomer, which is discussed with respect to the closer proximity of the quaternary nitrogens of the meta isomer to the metal center than that of the para isomer. The potency of Mn(II)Br(8)TM-3-PyP(4+) was corroborated by in vivo studies, where 500 nM allows SOD-deficient E. coli to grow >60% of the growth of wild type; at concentrations > or =5 microM it exhibits toxicity. Our work shows that exceptionally high k(cat) for the O2*- disproportionation can be achieved not only with an N(5)-type coordination motif, as rationalized previously for aza crown ether (cyclic polyamines) complexes, but also with a N(4)-type motif as in the Mn porphyrin case; both motifs sharing "up-down-up-down" steric arrangement.

Authors
DeFreitas-Silva, G; Rebouças, JS; Spasojević, I; Benov, L; Idemori, YM; Batinić-Haberle, I
MLA Citation
DeFreitas-Silva, G, Rebouças, JS, Spasojević, I, Benov, L, Idemori, YM, and Batinić-Haberle, I. "SOD-like activity of Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-3-yl)porphyrin equals that of the enzyme itself." Arch Biochem Biophys 477.1 (September 1, 2008): 105-112.
PMID
18477465
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
477
Issue
1
Publish Date
2008
Start Page
105
End Page
112
DOI
10.1016/j.abb.2008.04.032

Role of fructose in the adaptation of plants to cold-induced oxidative stress.

This work presents findings, which indicate important role of fructose, fructose 6-phosphate (F6P), and fructose 1,6-bisphosphate (FBP) in preservation of homeostasis in plants under low temperature. Cold combined with light is known to incite increased generation of superoxide in chloroplasts leading to photoinhibition, but also an increased level of soluble sugars. In the present study, oxidative stress in pea leaves provoked by cold/light regime was asserted by the observed decrease of the level of oxidized form of PSI pigment P700 (P700+). Alongside, the increased antioxidative status and the accumulation of fructose were observed. The antioxidative properties of fructose and its phosphorylated forms were evaluated to appraise their potential protective role in plants exposed to chilling stress. Fructose, and particularly F6P and FBP exhibited high capacities for scavenging superoxide and showed to be involved in antioxidative protection in pea leaves. These results combined with previously established links implicate that the increase in level of fructose sugars through various pathways intercalated into physiological mechanisms of homeostasis represents important non-enzymatic antioxidative defense in plants under cold-related stress.

Authors
Bogdanović, J; Mojović, M; Milosavić, N; Mitrović, A; Vucinić, Z; Spasojević, I
MLA Citation
Bogdanović, J, Mojović, M, Milosavić, N, Mitrović, A, Vucinić, Z, and Spasojević, I. "Role of fructose in the adaptation of plants to cold-induced oxidative stress." September 2008.
PMID
18214465
Source
epmc
Published In
European Biophysics Journal
Volume
37
Issue
7
Publish Date
2008
Start Page
1241
End Page
1246
DOI
10.1007/s00249-008-0260-9

Phase I evaluation of gemcitabine, mitoxantrone, and their effect on plasma disposition of fludarabine in patients with relapsed or refractory acute myeloid leukemia.

Our aim was to estimate the duration of maximum tolerated dose (MTD) duration for gemcitabine given as a continuous infusion in combination with fludarabine and mitoxantrone and to evaluate potential pharmacokinetic (PK) interactions in 17 patients with refractory or relapsed acute myeloid leukaemia (AML). Gemcitabine was administered at 10 mg/m(2)/min for 3-15 h, fludarabine at 25 mg/m(2) daily for days 1-5 and mitoxantrone at 10 mg/m(2) daily on days 1-3. PK studies revealed that fludarabine clearance was not affected by gemcitabine but mean terminal half-life and volume of distribution of fludarabine were slightly increased. The duration of MTD for gemcitabine was 12 h. Our previous in vitro work has demonstrated the binary combination of gemcitabine + fludarabine is most synergistic at a molar ratio around 0.002. However, with MTD dosing this drug ratio is not optimal to produce synergy and future studies using ratiometric dosing are required to confirm these findings.

Authors
Rao, AV; Younis, IR; Sand, GJ; Spasojevic, I; Adams, DJ; Decastro, CM; Gockerman, JP; Peterson, BL; Petros, WP; Moore, JO; Rizzieri, DA
MLA Citation
Rao, AV, Younis, IR, Sand, GJ, Spasojevic, I, Adams, DJ, Decastro, CM, Gockerman, JP, Peterson, BL, Petros, WP, Moore, JO, and Rizzieri, DA. "Phase I evaluation of gemcitabine, mitoxantrone, and their effect on plasma disposition of fludarabine in patients with relapsed or refractory acute myeloid leukemia." Leuk Lymphoma 49.8 (August 2008): 1523-1529.
PMID
18766965
Source
pubmed
Published In
Leukemia & Lymphoma (Informa)
Volume
49
Issue
8
Publish Date
2008
Start Page
1523
End Page
1529
DOI
10.1080/10428190802210700

Impact of electrostatics in redox modulation of oxidative stress by Mn porphyrins: protection of SOD-deficient Escherichia coli via alternative mechanism where Mn porphyrin acts as a Mn carrier.

Understanding the factors that determine the ability of Mn porphyrins to scavenge reactive species is essential for tuning their in vivo efficacy. We present herein the revised structure-activity relationships accounting for the critical importance of electrostatics in the Mn porphyrin-based redox modulation systems and show that the design of effective SOD mimics (per se) based on anionic porphyrins is greatly hindered by inappropriate electrostatics. A new strategy for the beta-octabromination of the prototypical anionic Mn porphyrins Mn(III) meso-tetrakis(p-carboxylatophenyl)porphyrin ([Mn(III)TCPP](3-) or MnTBAP(3-)) and Mn(III) meso-tetrakis(p-sulfonatophenyl)porphyrin ([Mn(III)TSPP](3-)), to yield the corresponding anionic analogues [Mn(III)Br(8)TCPP](3-) and [Mn(III)Br(8)TSPP](3-), respectively, is described along with characterization data, stability studies, and their ability to substitute for SOD in SOD-deficient Escherichia coli. Despite the Mn(III)/Mn(II) reduction potential of [Mn(III)Br(8)TCPP](3-) and [Mn(III)Br(8)TSPP](3-) being close to the SOD-enzyme optimum and nearly identical to that of the cationic Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin (Mn(III)TM-2-PyP(5+)), the SOD activity of both anionic brominated porphyrins ([Mn(III)Br(8)TCPP](3-), E(1/2)=+213 mV vs NHE, log k(cat)=5.07; [Mn(III)Br(8)TSPP](3-), E(1/2)=+209 mV, log k(cat)=5.56) is considerably lower than that of Mn(III)TM-2-PyP(5+) (E(1/2)=+220 mV, log k(cat)=7.79). This illustrates the impact of electrostatic guidance of O(2)(-) toward the metal center of the mimic. With low k(cat), the [Mn(III)TCPP](3-), [Mn(III)TSPP](3-), and [Mn(III)Br(8)TCPP](3-) did not rescue SOD-deficient E. coli. The striking ability of [Mn(III)Br(8)TSPP](3-) to substitute for the SOD enzymes in the E. coli model does not correlate with its log k(cat). In fact, the protectiveness of [Mn(III)Br(8)TSPP](3-) is comparable to or better than that of the potent SOD mimic Mn(III)TM-2-PyP(5+), even though the dismutation rate constant of the anionic complex is 170-fold smaller. Analyses of the medium and E. coli cell extract revealed that the major species in the [Mn(III)Br(8)TSPP](3-) system is not the Mn complex, but the free-base porphyrin [H(2)Br(8)TSPP](4-) instead. Control experiments with extracellular MnCl(2) showed the lack of E. coli protection, indicating that "free" Mn(2+) cannot enter the cell to a significant extent. We proposed herein the alternative mechanism where a labile Mn porphyrin [Mn(III)Br(8)TSPP](3-) is not an SOD mimic per se but carries Mn into the E. coli cell.

Authors
Rebouças, JS; DeFreitas-Silva, G; Spasojević, I; Idemori, YM; Benov, L; Batinić-Haberle, I
MLA Citation
Rebouças, JS, DeFreitas-Silva, G, Spasojević, I, Idemori, YM, Benov, L, and Batinić-Haberle, I. "Impact of electrostatics in redox modulation of oxidative stress by Mn porphyrins: protection of SOD-deficient Escherichia coli via alternative mechanism where Mn porphyrin acts as a Mn carrier." Free Radic Biol Med 45.2 (July 15, 2008): 201-210.
PMID
18457677
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
45
Issue
2
Publish Date
2008
Start Page
201
End Page
210
DOI
10.1016/j.freeradbiomed.2008.04.009

Spin-trapping of oxygen free radicals in chemical and biological systems: new traps, radicals and possibilities.

The choice of the spin-trap that is to be applied in any EPR study represents the crossroad between a comprehensive investigation and an "ordinary" quantification of production of radicals. So, the scope of our study was to compare the performance of different spin-traps for qualitative analysis of radical-generating systems, and their ability to recognize previously unnoticed radicals. In addition, we present a brief account of the difficulties involved in the detection of oxygen-centered radicals in chemical and biological systems accompanied by the rationale for using the EPR spin-trapping technique in quantitative studies of such reactive species. Certain technical aspects of EPR experiments related to efficient trapping of free radicals in biochemical systems are also discussed. As an example we present here results obtained using EPR spectroscopy and the spin-trap DEPMPO, which show that the Fenton reaction, as well as various biological systems generate a previously unappreciated hydrogen (*H) atom.

Authors
Bacić, G; Spasojević, I; Sećerov, B; Mojović, M
MLA Citation
Bacić, G, Spasojević, I, Sećerov, B, and Mojović, M. "Spin-trapping of oxygen free radicals in chemical and biological systems: new traps, radicals and possibilities." Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 69.5 (May 2008): 1354-1366.
PMID
18255335
Source
epmc
Published In
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Volume
69
Issue
5
Publish Date
2008
Start Page
1354
End Page
1366
DOI
10.1016/j.saa.2007.09.047

Evaluation of antioxidant capacity of Allium ursinum L. volatile oil and its effect on membrane fluidity

Authors
Gođevac, D; Vujisić, L; Mojović, M; Ignjatović, A; Spasojević, I; Vajs, V
MLA Citation
Gođevac, D, Vujisić, L, Mojović, M, Ignjatović, A, Spasojević, I, and Vajs, V. "Evaluation of antioxidant capacity of Allium ursinum L. volatile oil and its effect on membrane fluidity." Food Chemistry 107.4 (April 2008): 1692-1700.
Source
crossref
Published In
Food Chemistry
Volume
107
Issue
4
Publish Date
2008
Start Page
1692
End Page
1700
DOI
10.1016/j.foodchem.2007.10.017

Redox modulation of oxidative stress by Mn porphyrin-based therapeutics: the effect of charge distribution.

We evaluate herein the impact of positive charge distribution on the in vitro and in vivo properties of Mn porphyrins as redox modulators possessing the same overall 5+ charge and of minimal stericity demand: Mn(III) meso-tetrakis(trimethylanilinium-4-yl)porphyrin (MnTTriMAP(5+)), Mn(III) meso-tetrakis(N,N'-dimethylpyrazolium-4-yl)porphyrin (MnTDM-4-PzP(5+)), Mn(III) meso-tetrakis(N,N'-dimethylimidazolium-2-yl)porphyrin (MnTDM-2-ImP(5+)), and the ortho and para methylpyridinium complexes Mn(III) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (MnTM-4-PyP(5+)) and Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin (MnTM-2-PyP(5+)). Both Mn(III)/Mn(II) reduction potential and SOD activity within the series follow the order: MnTTriMAP(5+)

Authors
Rebouças, JS; Spasojević, I; Tjahjono, DH; Richaud, A; Méndez, F; Benov, L; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, Tjahjono, DH, Richaud, A, Méndez, F, Benov, L, and Batinić-Haberle, I. "Redox modulation of oxidative stress by Mn porphyrin-based therapeutics: the effect of charge distribution." Dalton Trans 9 (March 7, 2008): 1233-1242.
PMID
18283384
Source
pubmed
Published In
Dalton Transactions
Issue
9
Publish Date
2008
Start Page
1233
End Page
1242
DOI
10.1039/b716517j

Pure manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is not a superoxide dismutase mimic in aqueous systems: a case of structure-activity relationship as a watchdog mechanism in experimental therapeutics and biology.

Superoxide is involved in a plethora of pathological and physiological processes via oxidative stress and/or signal transduction pathways. Superoxide dismutase (SOD) mimics have, thus, been actively sought for clinical and mechanistic purposes. Manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is one of the most intensely explored "SOD mimics" in biology and medicine. However, we show here that this claimed SOD activity of MnTBAP in aqueous media is not corroborated by comprehensive structure-activity relationship studies for a wide set of Mn porphyrins and that MnTBAP from usual commercial sources contains different amounts of noninnocent trace impurities (Mn clusters), which inhibited xanthine oxidase and had SOD activity in their own right. In addition, the preparation and thorough characterization of a high-purity MnTBAP is presented for the first time and confirmed that pure MnTBAP has no SOD activity in aqueous medium. These findings call for an assessment of the relevance and suitability of using MnTBAP (or its impurities) as a mechanistic probe and antioxidant therapeutic; conclusions on the physiological and pathological role of superoxide derived from studies using MnTBAP of uncertain purity should be examined judiciously. An unequivocal distinction between the biological effects due to MnTBAP and that of its impurities can only be unambiguously made if a pure sample is/was used. This work also illustrates the contribution of fundamental structure-activity relationship studies not only for drug design and optimization, but also as a "watchdog" mechanism for checking/spotting eventual incongruence of drug activity in chemical and biological settings.

Authors
Rebouças, JS; Spasojević, I; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, and Batinić-Haberle, I. "Pure manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is not a superoxide dismutase mimic in aqueous systems: a case of structure-activity relationship as a watchdog mechanism in experimental therapeutics and biology." J Biol Inorg Chem 13.2 (February 2008): 289-302.
PMID
18046586
Source
pubmed
Published In
JBIC Journal of Biological Inorganic Chemistry
Volume
13
Issue
2
Publish Date
2008
Start Page
289
End Page
302
DOI
10.1007/s00775-007-0324-9

Fludarabine-based nonmyeloablative stem cell transplantation for sickle cell disease with and without renal failure: clinical outcome and pharmacokinetics.

End-organ damage is common in patients with sickle cell disease (SCD) thereby limiting the use of allogeneic stem cell transplantation (SCT). We report the outcome of 2 adult SCD patients, 1 with end-stage renal disease (ESRD), who underwent fludarabine-based nonmyeloablative SCT from HLA-identical matched siblings. To prevent fludarabine toxicity, the patient with ESRD underwent aggressive dialysis following adjusted fludarabine dosing. Pharmacokinetics of the fludarabine metabolite F-Ara-A was studied on the patient with ESRD and 2 additional patients with normal renal function. Both patients with SCD achieved full donor erythroid chimerism, have normal blood counts, and are on no immunosuppressive medications. With a 20% dose reduction followed by daily dialysis, we achieved fludarabine drug exposure that is nearly identical to that achieved in patients with normal renal function. We conclude that fludarabine-based nonmyeloablative allogeneic SCT for adult patients with SCD is feasible, even in the setting of ESRD.

Authors
Horwitz, ME; Spasojevic, I; Morris, A; Telen, M; Essell, J; Gasparetto, C; Sullivan, K; Long, G; Chute, J; Chao, N; Rizzieri, D
MLA Citation
Horwitz, ME, Spasojevic, I, Morris, A, Telen, M, Essell, J, Gasparetto, C, Sullivan, K, Long, G, Chute, J, Chao, N, and Rizzieri, D. "Fludarabine-based nonmyeloablative stem cell transplantation for sickle cell disease with and without renal failure: clinical outcome and pharmacokinetics." Biol Blood Marrow Transplant 13.12 (December 2007): 1422-1426.
PMID
18022571
Source
pubmed
Published In
Biology of Blood and Marrow Transplantation
Volume
13
Issue
12
Publish Date
2007
Start Page
1422
End Page
1426
DOI
10.1016/j.bbmt.2007.08.050

Design and synthesis of manganese porphyrins with tailored lipophilicity: investigation of redox properties and superoxide dismutase activity.

Thirteen new manganese porphyrins and two porphodimethenes bearing one to three different substituents at the meso positions in a variety of architectures have been synthesized. The substituents employed generally are (i) electron-withdrawing to tune the reduction potential to the desirable range (near +0.3V vs NHE), and/or (ii) lipophilic to target the interior of lipid bilayer membranes and/or the blood-brain barrier. The influence of the substituents on the Mn(III)/Mn(II) reduction potentials has been characterized, and the superoxide dismutase activity of the compounds has been examined.

Authors
Lahaye, D; Muthukumaran, K; Hung, C-H; Gryko, D; Rebouças, JS; Spasojević, I; Batinić-Haberle, I; Lindsey, JS
MLA Citation
Lahaye, D, Muthukumaran, K, Hung, C-H, Gryko, D, Rebouças, JS, Spasojević, I, Batinić-Haberle, I, and Lindsey, JS. "Design and synthesis of manganese porphyrins with tailored lipophilicity: investigation of redox properties and superoxide dismutase activity." Bioorg Med Chem 15.22 (November 15, 2007): 7066-7086.
PMID
17822908
Source
pubmed
Published In
Bioorganic & Medicinal Chemistry
Volume
15
Issue
22
Publish Date
2007
Start Page
7066
End Page
7086
DOI
10.1016/j.bmc.2007.07.015

Treatment with imatinib improves drug delivery and efficacy in NSCLC xenografts.

Imatinib, an inhibitor of PDGF-Rbeta and other tyrosine kinase receptors, has been shown to decrease microvessel density and interstitial fluid pressure in solid tumours, thereby improving subsequent delivery of small molecules. The purpose of this study was to test whether pretreatment with imatinib increases the efficacy of traditional chemotherapy in mice bearing non-small cell lung carcinoma xenografts, and to investigate the effects of imatinib on liposomal drug delivery. Efficacy treatment groups included (n=9-10): saline control, imatinib alone (oral gavage, 100 mg kg(-1) x 7 days), docetaxel alone (10 mg kg(-1) i.p. 2 x /week until killing), and imatinib plus docetaxel (started on day 7 of imatinib). Tumours were monitored until they reached four times the initial treatment volume (4 x V) or 28 days. A separate experiment compared tumour doxorubicin concentrations (using high performance liquid chromatography) 24 h after treatment with liposomal doxorubicin alone (6 mg kg(-1) i.v., n=9) or imatinib plus liposomal doxorubicin (n=16). Imatinib plus docetaxel resulted in significantly improved antitumour efficacy (0/10 animals reached 4 x V by 28 days) when compared to docetaxel alone (3/9 reached 4 x V, P=0.014) or imatinib alone (9/10 reached 4 x V, P=0.025). Pretreatment with imatinib also significantly increased tumour concentrations of liposomal doxorubicin. Overall, these preclinical studies emphasise the potential of imatinib as an adjunct to small molecule or liposomal chemotherapy.

Authors
Vlahovic, G; Ponce, AM; Rabbani, Z; Salahuddin, FK; Zgonjanin, L; Spasojevic, I; Vujaskovic, Z; Dewhirst, MW
MLA Citation
Vlahovic, G, Ponce, AM, Rabbani, Z, Salahuddin, FK, Zgonjanin, L, Spasojevic, I, Vujaskovic, Z, and Dewhirst, MW. "Treatment with imatinib improves drug delivery and efficacy in NSCLC xenografts." Br J Cancer 97.6 (September 17, 2007): 735-740.
PMID
17712313
Source
pubmed
Published In
British Journal of Cancer
Volume
97
Issue
6
Publish Date
2007
Start Page
735
End Page
740
DOI
10.1038/sj.bjc.6603941

Mn porphyrin-based superoxide dismutase (SOD) mimic, MnIIITE-2-PyP5+, targets mouse heart mitochondria.

The Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnIIITE-2-PyP5+ (AEOL-10113) has proven effective in treating oxidative stress-induced conditions including cancer, radiation damage, diabetes, and central nervous system trauma. The ortho cationic pyridyl nitrogens of MnTE-2-PyP5+ are essential for its high antioxidant potency. The exceptional ability of MnIIITE-2-PyP5+ to dismute O2.- parallels its ability to reduce ONOO- and CO3-. Decreasing levels of these species are considered its predominant mode of action, which may also involve redox regulation of signaling pathways. Recently, Ferrer-Sueta at al. (Free Radic. Biol. Med. 41:503-512; 2006) showed, with submitochondrial particles, that>or=3 microM MnIIITE-2-PyP5+ was able to protect components of the mitochondrial electron transport chain from peroxynitrite-mediated damage. Our study complements their data in showing, for the first time that micromolar mitochondrial concentrations of MnIIITE-2-PyP5+ are obtainable in vivo. For this study we have developed a new and sensitive method for MnIIITE-2-PyP5+ determination in tissues. The method is based on the exchange of porphyrin Mn2+ with Zn2+, followed by the HPLC/fluorescence detection of ZnIITE-2-PyP4+. At 4 and 7 h after a single 10 mg/kg intraperitoneal administration of MnIIITE-2-PyP5+, the mice (8 in total) were anesthetized and perfused with saline. Mitochondria were then isolated by the method of Mela and Seitz (Methods Enzymol.55:39-46; 1979). We found MnIIITE-2-PyP5+ localized in heart mitochondria to 2.95 ng/mg protein. Given the average value of mitochondrial volume of 0.6 microL/mg protein, the calculated MnIIITE-2-PyP5+ concentration is 5.1 microM, which is sufficient to protect mitochondria from oxidative damage. This study establishes, for the first time, that MnIIITE-2-PyP5+, a highly charged metalloporphyrin, is capable of entering mitochondria in vivo at levels sufficient to exert there its antioxidant action; such a result encourages its development as a prospective therapeutic agent.

Authors
Spasojević, I; Chen, Y; Noel, TJ; Yu, Y; Cole, MP; Zhang, L; Zhao, Y; St Clair, DK; Batinić-Haberle, I
MLA Citation
Spasojević, I, Chen, Y, Noel, TJ, Yu, Y, Cole, MP, Zhang, L, Zhao, Y, St Clair, DK, and Batinić-Haberle, I. "Mn porphyrin-based superoxide dismutase (SOD) mimic, MnIIITE-2-PyP5+, targets mouse heart mitochondria." Free Radic Biol Med 42.8 (April 15, 2007): 1193-1200.
PMID
17382200
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
42
Issue
8
Publish Date
2007
Start Page
1193
End Page
1200
DOI
10.1016/j.freeradbiomed.2007.01.019

Pharmacodynamic and pharmacokinetic study of chronic low-dose metronomic cyclophosphamide therapy in mice

Prolonged, frequently administered low-dose metronomic chemotherapy (LDM) is being explored (pre)clinically as a promising antiangiogenic antitumor strategy. Although appealing because of a favorable side effect profile and mostly oral dosing, LDM involves new challenges different from conventional maximum tolerated dose chemotherapy. These include possible altered pharmacokinetic characteristics due to long-term drug exposure potentially resulting in acquired resistance and increased risk of unfavorable drug interactions. We therefore compared the antitumor and antivascular effects of LDM cyclophosphamide (CPA) given to mice that had been pretreated with either LDM CPA or normal saline, obtained blood 4-hydroxy-CPA (activated CPA) concentrations using either gas chromatography/mass spectrometry or liquid chromatography/tandem mass spectrometry in mice treated with LDM CPA, and measured hepatic and intratumoral activity of enzymes involved in the biotransformation of CPA and many other drugs [i.e., cytochrome P450 3A4 (CYP3A4) and aldehyde dehydrogenase]. Exposure of mice to LDM CPA for ≥8 weeks did not compromise subsequent activity of LDM CPA therapy, and biologically active 4-hydroxy-CPA levels were maintained during long-term LDM CPA administration. Whereas the effects on CYP3A4 were complex, aldehyde dehydrogenase activity was not affected. In summary, our findings suggest that acquired resistance to LDM CPA is unlikely accounted for by altered CPA biotransformation. In the absence of reliable pharmacodynamic surrogate markers, pharmacokinetic parameters might become helpful to individualize/optimize LDM CPA therapy. LDM CPA-associated changes of CYP3A4 activity point to a potential risk of unfavorable drug interactions when compounds that are metabolized by CYP3A4 are coadministered with LDM CPA. Copyright © 2007 American Association for Cancer Research.

Authors
Emmenegger, U; Shaked, Y; Man, S; Bocci, G; Spasojevic, I; Francia, G; Kouri, A; Coke, R; Cruz-Munoz, W; Ludeman, SM; Colvin, OM; Kerbel, RS
MLA Citation
Emmenegger, U, Shaked, Y, Man, S, Bocci, G, Spasojevic, I, Francia, G, Kouri, A, Coke, R, Cruz-Munoz, W, Ludeman, SM, Colvin, OM, and Kerbel, RS. "Pharmacodynamic and pharmacokinetic study of chronic low-dose metronomic cyclophosphamide therapy in mice." Molecular Cancer Therapeutics 6.8 (2007): 2280-2289.
PMID
17671082
Source
scival
Published In
Molecular cancer therapeutics
Volume
6
Issue
8
Publish Date
2007
Start Page
2280
End Page
2289
DOI
10.1158/1535-7163.MCT-07-0181

Suppression of RelB-mediated manganese superoxide dismutase expression reveals a primary mechanism for radiosensitization effect of 1α,25-dihydroxyvitamin D3 in prostate cancer cells

Nuclear factor-κB provides an adaptive response to protect cancer cells against cytotoxicity induced by redox active therapeutics. RelB is uniquely expressed at a high level in prostate cancer with high Gleason scores. Recently, we showed that the level of RelB rapidly increases in androgen-independent prostate cancer cells after exposure to ionizing radiation (IR), leading to a reduction in intrinsic radiosensitivity. Here, we show that interaction of 1α,25-dihydroxyvitamin D3 [1α,25-(OH) 2D3] with the vitamin D receptor significantly enhances radiosensitivity of prostate cancer cells at clinically relevant radiation doses. The radiosensitization effect of 1α,25-(OH)2D 3 is mediated, at least in part, by selectively suppressing IR-mediated RelB activation, leading to a reduced expression of its target gene MnSOD, a primary antioxidant enzyme in mitochondria. These results suggest that suppression of manganese superoxide dismutase is a mechanism by which 1α,25-(OH)2D3 exerts its radiosensitization effect and that 1α,25-(OH)2D3 may serve as an effective pharmacologic agent for selectively sensitizing prostate cancer cells to IR via suppression of antioxidant responses in mitochondria. Copyright © 2007 American Association for Cancer Research.

Authors
Xu, Y; Fang, F; Clair, DKS; Josson, S; Sompol, P; Spasojevic, I; Clair, WHS
MLA Citation
Xu, Y, Fang, F, Clair, DKS, Josson, S, Sompol, P, Spasojevic, I, and Clair, WHS. "Suppression of RelB-mediated manganese superoxide dismutase expression reveals a primary mechanism for radiosensitization effect of 1α,25-dihydroxyvitamin D3 in prostate cancer cells." Molecular Cancer Therapeutics 6.7 (2007): 2048-2056.
PMID
17604335
Source
scival
Published In
Molecular cancer therapeutics
Volume
6
Issue
7
Publish Date
2007
Start Page
2048
End Page
2056
DOI
10.1158/1535-7163.MCT-06-0700

A tracer dose of technetium-99m-labeled liposomes can estimate the effect of hyperthermia on intratumoral doxil extravasation.

PURPOSE: A noninvasive method to monitor intratumoral Doxil delivery in individual patients during targeted tumor therapy is important to predict treatment response. The purpose of this study was to determine if a small tracer dose of technetium-99m (99mTc)-labeled liposomes could be used to quantify the effect of local hyperthermia on intratumoral Doxil extravasation. EXPERIMENTAL DESIGN: Experiments were carried out in a rat fibrosarcoma model with transplanted thigh tumors. Liposomes of approximately same size and composition as Doxil were radiolabeled using [technetium-99m (99mTc)]exametazime. Eight treatment groups received either Doxil, a tracer dose or a large dose of 99mTc-labeled liposomes, or a combination of tracer and Doxil, with or without hyperthermia. This design was chosen to assure that coadministration of both liposomal formulations did not influence their intratumoral distribution. Hyperthermia was done for 45 minutes. Scintigraphic images were obtained at 5 and 18 hours. At 18 hours, tumors were removed and gamma counts as well as doxorubicin concentrations were measured. RESULTS: Intratumoral extravasation of the 99mTc-labeled tracer could be imaged scintigraphically under normothermic and hyperthermic conditions. The thermal enhancement ratio was slightly higher for radiolabeled liposomes than for doxorubicin concentration. However, there was a significant positive correlation of intratumoral doxorubicin concentration and intratumoral uptake of the radiolabeled tracer (expressed as percentage of the injected dose per gram of tissue). Coadministration of radiolabeled liposomes did not negatively influence the amount of drug delivered with Doxil. CONCLUSIONS: The use of a radiolabeled tracer has potential value to monitor drug delivery and estimate the effect of an intervention aimed to increase liposomal accumulation, such as local hyperthermia.

Authors
Kleiter, MM; Yu, D; Mohammadian, LA; Niehaus, N; Spasojevic, I; Sanders, L; Viglianti, BL; Yarmolenko, PS; Hauck, M; Petry, NA; Wong, TZ; Dewhirst, MW; Thrall, DE
MLA Citation
Kleiter, MM, Yu, D, Mohammadian, LA, Niehaus, N, Spasojevic, I, Sanders, L, Viglianti, BL, Yarmolenko, PS, Hauck, M, Petry, NA, Wong, TZ, Dewhirst, MW, and Thrall, DE. "A tracer dose of technetium-99m-labeled liposomes can estimate the effect of hyperthermia on intratumoral doxil extravasation." Clin Cancer Res 12.22 (November 15, 2006): 6800-6807.
PMID
17121901
Source
pubmed
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
12
Issue
22
Publish Date
2006
Start Page
6800
End Page
6807
DOI
10.1158/1078-0432.CCR-06-0839

New approach to the activation of anti-cancer pro-drugs by metalloporphyrin-based cytochrome P450 mimics in all-aqueous biologically relevant system.

The low-molecular weight water-soluble Fe(III) and Mn(III) porphyrins--in biologically relevant phosphate-buffered saline medium with ascorbic acid as a source of electrons, under aerobic conditions but without co-oxidant - catalyze the hydroxylation of anti-cancer drug cyclophosphamide to active metabolite 4-hydroxycyclophosphamide in yields similar or higher than those typically obtained by the action of liver enzymes in vivo. The Fe(III) meso tetrakis(2,6-difluoro-3-sulfonatophenyl)porphyrin, highly electron-deficient at the metal site, was the most effective catalyst. If proven viable in vivo, this methodology could be expanded to localized or systemic activation of the entire family of oxazaphosphorine-based (and many other) anti-cancer drugs and become a powerful tool for an aggressive treatment of tumors with less toxic side effects to the patient.

Authors
Spasojević, I; Colvin, OM; Warshany, KR; Batinić-Haberle, I
MLA Citation
Spasojević, I, Colvin, OM, Warshany, KR, and Batinić-Haberle, I. "New approach to the activation of anti-cancer pro-drugs by metalloporphyrin-based cytochrome P450 mimics in all-aqueous biologically relevant system." J Inorg Biochem 100.11 (November 2006): 1897-1902.
PMID
16965820
Source
pubmed
Published In
Journal of Inorganic Biochemistry
Volume
100
Issue
11
Publish Date
2006
Start Page
1897
End Page
1902
DOI
10.1016/j.jinorgbio.2006.07.013

Phase I trial of doxorubicin-containing low temperature sensitive liposomes in spontaneous canine tumors.

PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicities, and pharmacokinetic characteristics of doxorubicin encapsulated in a low temperature sensitive liposome (LTSL) when given concurrently with local hyperthermia to canine solid tumors. EXPERIMENTAL DESIGN: Privately owned dogs with solid tumors (carcinomas or sarcomas) were treated. The tumors did not involve bone and were located at sites amenable to local hyperthermia. LTSL-doxorubicin was given (0.7-1.0 mg/kg i.v.) over 30 minutes during local tumor hyperthermia in a standard phase I dose escalation study. Three treatments, given 3 weeks apart, were scheduled. Toxicity was monitored for an additional month. Pharmacokinetics were evaluated during the first treatment cycle. RESULTS: Twenty-one patients were enrolled: 18 with sarcomas and 3 with carcinomas. Grade 4 neutropenia and acute death secondary to liver failure, possibly drug related, were the dose-limiting toxicities. The maximum tolerated dose was 0.93 mg/kg. Other toxicities, with the possible exception of renal damage, were consistent with those observed following free doxorubicin administration. Of the 20 dogs that received > or = 2 doses of LTSL-doxorubicin, 12 had stable disease, and 6 had a partial response to treatment. Pharmacokinetic variables were more similar to those of free doxorubicin than the marketed liposomal product. Tumor drug concentrations at a dose of 1.0 mg/kg averaged 9.12 +/- 6.17 ng/mg tissue. CONCLUSION: LTSL-doxorubicin offers a novel approach to improving drug delivery to solid tumors. It was well tolerated and resulted in favorable response profiles in these patients. Additional evaluation in human patients is warranted.

Authors
Hauck, ML; LaRue, SM; Petros, WP; Poulson, JM; Yu, D; Spasojevic, I; Pruitt, AF; Klein, A; Case, B; Thrall, DE; Needham, D; Dewhirst, MW
MLA Citation
Hauck, ML, LaRue, SM, Petros, WP, Poulson, JM, Yu, D, Spasojevic, I, Pruitt, AF, Klein, A, Case, B, Thrall, DE, Needham, D, and Dewhirst, MW. "Phase I trial of doxorubicin-containing low temperature sensitive liposomes in spontaneous canine tumors." Clin Cancer Res 12.13 (July 1, 2006): 4004-4010.
PMID
16818699
Source
pubmed
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
12
Issue
13
Publish Date
2006
Start Page
4004
End Page
4010
DOI
10.1158/1078-0432.CCR-06-0226

New PEG-ylated Mn(III) porphyrins approaching catalytic activity of SOD enzyme.

Two new tri(ethyleneglycol)-derivatized Mn(III) porphyrins were synthesized with the aim of increasing their bioavailability, and blood-circulating half-life. These are Mn(III) tetrakis(N-(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)pyridinium-2-yl)porphyrin, MnTTEG-2-PyP5+ and Mn(III) tetrakis(N,N'-di(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)imidazolium-2-yl)porphyrin, MnTDTEG-2-ImP5+. Both porphyrins have ortho pyridyl or di-ortho imidazolyl electron-withdrawing substituents at meso positions of the porphyrin ring that assure highly positive metal centered redox potentials, E1/2 = +250 mV vs. NHE for MnTTEG-2-PyP5+ and E1/2 = + 412 mV vs. NHE for MnTDTEG-2-ImP5+. As expected, from established E1/2 vs. log kcat(O2 *-) structure-activity relationships for metalloporphyrins (Batinic-Haberle et al., Inorg. Chem., 1999, 38, 4011), both compounds exhibit higher SOD-like activity than any meso-substituted Mn(III) porphyrins-based SOD mimic thus far, log kcat = 8.11 (MnTTEG-2-PyP5+) and log kcat = 8.55 (MnTDTEG-2-ImP5+), the former being only a few-fold less potent in disproportionating O2*- than the SOD enzyme itself. The new porphyrins are stable to both acid and EDTA, and non toxic to E. coli. Despite elongated substituents, which could potentially lower their ability to cross the cell wall, MnTTEG-2-PyP5+ and MnTDTEG-2-ImP5+ exhibit similar protection of SOD-deficient E. coli as their much smaller ethyl analogues MnTE-2-PyP5+ and MnTDE-2-ImP5+, respectively. Consequently, with anticipated increased blood-circulating half-life, these new Mn(III) porphyrins may be more effective in ameliorating oxidative stress injuries than ethyl analogues that have been already successfully explored in vivo.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Bondurant, B; Okado-Matsumoto, A; Fridovich, I; Vujasković, Z; Dewhirst, MW
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Bondurant, B, Okado-Matsumoto, A, Fridovich, I, Vujasković, Z, and Dewhirst, MW. "New PEG-ylated Mn(III) porphyrins approaching catalytic activity of SOD enzyme." Dalton Trans 4 (January 28, 2006): 617-624.
PMID
16402149
Source
pubmed
Published In
Dalton Transactions
Issue
4
Publish Date
2006
Start Page
617
End Page
624
DOI
10.1039/b513761f

Detection of hydrogen atom adduct of spin-trap DEPMPO. The relevance for studies of biological systems.

We proposed EPR spectroscopy using spin-trap DEPMPO as a novel method for the detection of a hydrogen atom (*H) produced by chemical and biological systems. In complex EPR spectra of DEPMPO adducts in biological systems, spectral lines of unknown origin have been observed. We have assumed (Bacić, G.; Mojović, M. Ann. N. Y. Acad. Sci. 2005, 1048, 230-243) that those lines represent the spectrum of a hydrogen atom (*H) adduct i.e., DEPMPO/H. An electrochemical system known to produce only *H radicals was used here in order to obtain a separate spectrum of the DEPMPO/H adduct. An acquired spectrum as well as a computer spectral simulation of the DEPMPO/H adduct showed considerable resemblance with additional lines in the EPR spectra of DEPMPO adducts in biological systems-plant plasma membranes and cell walls. This shows that such a radical is produced by plants as well as that DEPMPO is suitable for detection in both electrochemical and biological systems.

Authors
Mojović, M; Spasojević, I; Bacić, G
MLA Citation
Mojović, M, Spasojević, I, and Bacić, G. "Detection of hydrogen atom adduct of spin-trap DEPMPO. The relevance for studies of biological systems." November 2005.
PMID
16309278
Source
epmc
Published In
Journal of Chemical Information and Modeling
Volume
45
Issue
6
Publish Date
2005
Start Page
1716
End Page
1718
DOI
10.1021/ci050173d

Effects of 5-fluorouracil on erythrocytes in relation to its cardiotoxicity: membrane structure and functioning.

In the present study, we showed that the antineoplastic drug 5-fluorouracil (5-FU) induces in vitro exposure-time/dose-dependent changes on the level of an erythrocyte's morphology, ionic balance, and membrane fluidity. These changes are partially or fully irreversible, and we suggest that they are provoked by an irreversible depletion of ATP. Because of these changes that could also occur in vivo during 5-FU infusion, a certain amount of erythrocytes with echinocytic shape and diminished ability to deliver oxygen is present in blood for longer periods of time. This renders oxygen transport and delivery more difficult, leaving the heart with an insufficient supply of oxygen, thus leading to cardiotoxicity.

Authors
Spasojević, I; Maksimović, V; Zakrzewska, J; Bacić, G
MLA Citation
Spasojević, I, Maksimović, V, Zakrzewska, J, and Bacić, G. "Effects of 5-fluorouracil on erythrocytes in relation to its cardiotoxicity: membrane structure and functioning." November 2005.
PMID
16309273
Source
epmc
Published In
Journal of Chemical Information and Modeling
Volume
45
Issue
6
Publish Date
2005
Start Page
1680
End Page
1685
DOI
10.1021/ci0501746

A manganese porphyrin superoxide dismutase mimetic enhances tumor radioresponsiveness.

PURPOSE: To determine the effect of the superoxide dismutase mimetic Mn(III) tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) on tumor radioresponsiveness. METHODS AND MATERIALS: Various rodent tumor (4T1, R3230, B16) and endothelial (SVEC) cell lines were exposed to MnTE-2-PyP(5+) and assayed for viability and radiosensitivity in vitro. Next, tumors were treated with radiation and MnTE-2-PyP(5+)in vivo, and the effects on tumor growth and vascularity were monitored. RESULTS: In vitro, MnTE-2-PyP(5+) was not significantly cytotoxic. However, at concentrations as low as 2 mumol/L it caused 100% inhibition of secretion by tumor cells of cytokines protective of irradiated endothelial cells. In vivo, combined treatment with radiation and MnTE-2-PyP(5+) achieved synergistic tumor devascularization, reducing vascular density by 78.7% within 72 h of radiotherapy (p < 0.05 vs. radiation or drug alone). Co-treatment of tumors also resulted in synergistic antitumor effects, extending tumor growth delay by 9 days (p < 0.01). CONCLUSIONS: These studies support the conclusion that MnTE-2-PyP(5+), which has been shown to protect normal tissues from radiation injury, can also improve tumor control through augmenting radiation-induced damage to the tumor vasculature.

Authors
Moeller, BJ; Batinic-Haberle, I; Spasojevic, I; Rabbani, ZN; Anscher, MS; Vujaskovic, Z; Dewhirst, MW
MLA Citation
Moeller, BJ, Batinic-Haberle, I, Spasojevic, I, Rabbani, ZN, Anscher, MS, Vujaskovic, Z, and Dewhirst, MW. "A manganese porphyrin superoxide dismutase mimetic enhances tumor radioresponsiveness." Int J Radiat Oncol Biol Phys 63.2 (October 1, 2005): 545-552.
PMID
16168847
Source
pubmed
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
63
Issue
2
Publish Date
2005
Start Page
545
End Page
552
DOI
10.1016/j.ijrobp.2005.05.026

31P NMR spectroscopy and polarographic combined study of erythrocytes treated with 5-fluorouracil: cardiotoxicity-related changes in ATP, 2,3-BPG, and O2 metabolism.

Antineoplastic drug 5-fluorouracil (5-FU) frequently shows cardiotoxic effects, the mechanism of which has not yet been elucidated. The objective of the present study was to explore effects of 5-FU on metabolism of ATP, 2,3-BPG, and oxygen in erythrocytes and to relate these to the phenomenon of 5-FU cardiotoxicity. We determined that 5-FU induced rapid increase in O(2) consumption, which led to drastic changes in the metabolism of phosphate compounds in erythrocytes. Decrease in pO(2) provoked increase in production of 2,3-BPG and subsequent deoxygenation of oxyHb to deoxyHb. However, the most important effect of 5-FU on erythrocytes is severe decrease in the level of ATP. This could lead to a number of irreversible changes in erythrocyte structure and functioning, such as echinocytosis, increase in membrane fluidity, and non-functioning of membrane ion pumps. All these changes affect normal functioning of erythrocytes, leading to difficulties in oxygen transport and insufficient supply of oxygen to the heart, and pointing to the importance of studying the effects of antineoplastic drugs on intracellular metabolism of erythrocytes.

Authors
Spasojević, I; Zakrzewska, J; Bacić, GG
MLA Citation
Spasojević, I, Zakrzewska, J, and Bacić, GG. "31P NMR spectroscopy and polarographic combined study of erythrocytes treated with 5-fluorouracil: cardiotoxicity-related changes in ATP, 2,3-BPG, and O2 metabolism." June 2005.
PMID
16154943
Source
epmc
Published In
Annals of the New York Academy of Sciences
Volume
1048
Publish Date
2005
Start Page
311
End Page
320
DOI
10.1196/annals.1342.028

Phase I/II trial of intravenous Doxil and whole abdomen hyperthermia in patients with refractory ovarian cancer.

OBJECTIVE: A phase I/II study of Doxil combined with whole abdomen hyperthermia was conducted in patients with refractory ovarian cancer. Liposomal doxorubicin combined with hyperthermia has been shown to increase both liposomal delivery and drug extravasation into tumour xenografts resulting in enhanced cytotoxic effects. PATIENTS AND METHODS: Thirty patients with either recurrent or persistent epithelial ovarian cancer were enrolled. All patients had either measurable or assessable disease. Patients received intravenous (IV) Doxil at a dose of 40 mg m-2 as a 1-h infusion followed by whole abdomen hyperthermia. The phase I portion of the study was performed to determine the maximal tolerated dose (MTD) of hyperthermia. Quality of life (QoL) was performed at baseline, prior to each cycle and every 3 months. Plasma pharmacokinetic studies were performed with the first cycle. RESULTS: Ten patients participated in the phase I portion of the study which demonstrated that the MTD of hyperthermia was 60 min after either average vaginal and rectal temperatures of 40 degrees C had been achieved or after 30 min of power application, whichever was shorter. All 30 patients were either paclitaxel and/or platinum resistant initially or developed resistant disease. The median number of prior chemotherapeutic regimens was three (range 2-8) and six patients had been previously treated with Doxil. There were three partial responses for a response rate of 10% (95% CI: [2%, 27%]) and eight patients (27%; 95% CI: [12%, 46%]) had disease stabilization. The median time to progression or death was 3.4 months (95% CI: [2.6, 5.2]) and the median survival was 10.8 months (95% CI: [8.8, 17.4]). Twelve patients (40%) experienced palmar-plantar erythrodysesthesia (PPE), but only four (13%) experienced grade 3-4 PPE toxicity. Doxil systemic exposure was higher in those with grade 3-4 PPE compared to those with no PPE. None of the patients had grade 3-4 thermal toxicity due to hyperthermia. QoL was not decreased in patients responding to therapy. CONCLUSIONS: Therapy with intravenous Doxil and whole abdomen hyperthermia for patients with platinum/paclitaxel resistant ovarian cancer is feasible and does not negatively impact quality of life.

Authors
Alvarez Secord, A; Jones, EL; Hahn, CA; Petros, WP; Yu, D; Havrilesky, LJ; Soper, JT; Berchuck, A; Spasojevic, I; Clarke-Pearson, DL; Prosnitz, LR; Dewhirst, MW
MLA Citation
Alvarez Secord, A, Jones, EL, Hahn, CA, Petros, WP, Yu, D, Havrilesky, LJ, Soper, JT, Berchuck, A, Spasojevic, I, Clarke-Pearson, DL, Prosnitz, LR, and Dewhirst, MW. "Phase I/II trial of intravenous Doxil and whole abdomen hyperthermia in patients with refractory ovarian cancer." Int J Hyperthermia 21.4 (June 2005): 333-347.
PMID
16019859
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
21
Issue
4
Publish Date
2005
Start Page
333
End Page
347
DOI
10.1080/02656730500110155

An EPR spin-probe and spin-trap study of the free radicals produced by plant plasma membranes

Authors
Mojovic, M; Spasojevic, I; Vuletic, M; Vucinic, Z; Bacic, G
MLA Citation
Mojovic, M, Spasojevic, I, Vuletic, M, Vucinic, Z, and Bacic, G. "An EPR spin-probe and spin-trap study of the free radicals produced by plant plasma membranes." Journal of the Serbian Chemical Society 70.2 (2005): 177-186.
Source
crossref
Published In
Journal of the Serbian Chemical Society
Volume
70
Issue
2
Publish Date
2005
Start Page
177
End Page
186
DOI
10.2298/JSC0502177M

Mouse spinal cord compression injury is ameliorated by intrathecal cationic manganese(III) porphyrin catalytic antioxidant therapy.

This study evaluated the effects of the cationic manganese(III) tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin catalytic antioxidant Mn(III)TDE-2-ImP5+ (AEOL 10150) on outcome from spinal cord compression (SCC) in the mouse. C57BL/6J mice were subjected to 60 min thoracic SCC after discontinuation of halothane anesthesia. In Experiment 1, mice were given intravenous Mn(III)TDE-2-ImP5+ (0.5 mg/kg bolus followed by 1 mg kg(-1) h(-1) for 24 h), methylprednisolone (30 mg/kg bolus followed by 5.4 mg kg(-1) h(-1) for 24 h), or vehicle (n = 25 per group). In Experiment 2, mice were given intrathecal Mn(III)TDE-2-ImP5+ (2.5 or 5.0 microg/kg) or vehicle (n = 18 per group). In both experiments, treatment began 5 min post-SCC onset. Rotarod performance was measured on post-SCC days 3, 7, 14, and 21. On post-SCC day 21, the spinal cord was histologically examined and a total damage score was calculated. Neither intravenous Mn(III)TDE-2-ImP5+ nor methylprednisolone altered rotarod performance (accelerated rate P = 0.11, fixed rate P = 0.11) or mean +/- S.D. total damage score (Mn(III)TDE-2-ImP5+ = 21 +/- 9, methylprednisolone = 24 +/- 8, vehicle = 22 +/- 10; P = 0.47; shams = 0). Intrathecal Mn(III)TDE-2-ImP5+ (both 2.5 and 5.0 microg) given at SCC-onset improved rotarod performance (P = 0.05) and total damage score (2.5 microg = 19 +/- 10, P = 0.04; 5.0 microg =19 +/- 8, P = 0.03) versus vehicle (26 +/- 10). These studies demonstrate sustained benefit from manganese(III) porphyrin catalytic antioxidant therapy after SCC. However, efficacy was dependent upon route of administration suggesting that bioavailability is critical in defining efficacy.

Authors
Sheng, H; Spasojevic, I; Warner, DS; Batinic-Haberle, I
MLA Citation
Sheng, H, Spasojevic, I, Warner, DS, and Batinic-Haberle, I. "Mouse spinal cord compression injury is ameliorated by intrathecal cationic manganese(III) porphyrin catalytic antioxidant therapy." Neurosci Lett 366.2 (August 12, 2004): 220-225.
PMID
15276251
Source
pubmed
Published In
Neuroscience Letters
Volume
366
Issue
2
Publish Date
2004
Start Page
220
End Page
225
DOI
10.1016/j.neulet.2004.05.050

Tetrahydrobiopterin rapidly reduces the SOD mimic Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin.

Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) effectively scavenges reactive oxygen and nitrogen species in vitro, and protects in vivo, in different rodent models of oxidative stress injuries. Further, Mn(III)TE-2-PyP(5+) was shown to be readily reduced by cellular reductants such as ascorbic acid and glutathione. We now show that tetrahydrobiopterin (BH(4)) is also able to reduce the metal center. Under anaerobic conditions, in phosphate-buffered saline (pH 7.4) at 25 +/- 0.1 degrees C, reduction of Mn(III)TE-2-PyP(5+) occurs through two reaction steps with rate constants k(1) = 1.0 x 10(4) M(-1) s(-1) and k(2) = 1.5 x 10(3) M(-1) s(-1). We ascribe these steps to the formation of tetrahydrobiopterin radical (BH(4)(.+)) (k(1)) that then undergoes oxidation to 6,7-dihydro-8H-biopterin (k(2)), which upon rearrangement gives rise to 7,8-dihydrobiopterin (7,8-BH(2)). Under aerobic conditions, Mn(III)TE-2-PyP(5+) catalytically oxidizes BH(4). This is also true for its longer chain alkyl analog, Mn(III) ortho-tetrakis(N-n-octylpyridinium-2-yl)porphyrin. The reduced Mn(II) porphyrin cannot be oxidized by 7,8-BH(2) or by l-sepiapterin. The data are discussed with regard to the possible impact of the interaction of Mn(III)TE-2-PyP(5+) with BH(4) on endothelial cell proliferation and hence on tumor antiangiogenesis via inhibition of nitric oxide synthase.

Authors
Batinić-Haberle, I; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Fridovich, I. "Tetrahydrobiopterin rapidly reduces the SOD mimic Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin." Free Radic Biol Med 37.3 (August 1, 2004): 367-374.
PMID
15223070
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
37
Issue
3
Publish Date
2004
Start Page
367
End Page
374
DOI
10.1016/j.freeradbiomed.2004.04.041

New class of potent catalysts of O2.-dismutation. Mn(III) ortho-methoxyethylpyridyl- and di-ortho-methoxyethylimidazolylporphyrins.

Three new Mn(III) porphyrin catalysts of O2.-dismutation (superoxide dismutase mimics), bearing ether oxygen atoms within their side chains, were synthesized and characterized: Mn(III) 5,10,15,20-tetrakis[N-(2-methoxyethyl)pyridinium-2-yl]porphyrin (MnTMOE-2-PyP(5+)), Mn(III)5,10,15,20-tetrakis[N-methyl-N'-(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTM,MOE-2-ImP(5+)) and Mn(III) 5,10,15,20-tetrakis[N,N'-di(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTDMOE-2-ImP(5+)). Their catalytic rate constants for O2.-dismutation (disproportionation) and the related metal-centered redox potentials vs. NHE are: log k(cat)= 8.04 (E(1/2)=+251 mV) for MnTMOE-2-PyP(5+), log k(cat)= 7.98 (E(1/2)=+356 mV) for MnTM,MOE-2-ImP(5+) and log k(cat)= 7.59 (E(1/2)=+365 mV) for MnTDMOE-2-ImP(5+). The new porphyrins were compared to the previously described SOD mimics Mn(III) 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)), Mn(III) 5,10,15,20-tetrakis(N-n-butylpyridinium-2-yl)porphyrin (MnTnBu-2-PyP(5+)) and Mn(III) 5,10,15,20-tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin (MnTDE-2-ImP(5+)). MnTMOE-2-PyP(5+) has side chains of the same length and the same E(1/2), as MnTnBu-2-PyP(5+)(k(cat)= 7.25, E(1/2)=+ 254 mV), yet it is 6-fold more potent a catalyst of O2.-dismutation , presumably due to the presence of the ether oxygen. The log k(cat)vs. E(1/2) relationship for all Mn porphyrin-based SOD mimics thus far studied is discussed. None of the new compounds were toxic to Escherichia coli in the concentration range studied (up to 30 microM), and protected SOD-deficient E. coli in a concentration-dependent manner. At 3 microM levels, the MnTDMOE-2-ImP(5+), bearing an oxygen atom within each of the eight side chains, was the most effective and offered much higher protection than MnTE-2-PyP(5+), while MnTDE-2-ImP(5+) was of very low efficacy.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Hambright, P; Neta, P; Okado-Matsumoto, A; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Hambright, P, Neta, P, Okado-Matsumoto, A, and Fridovich, I. "New class of potent catalysts of O2.-dismutation. Mn(III) ortho-methoxyethylpyridyl- and di-ortho-methoxyethylimidazolylporphyrins." Dalton Trans 11 (June 7, 2004): 1696-1702.
PMID
15252564
Source
pubmed
Published In
Dalton Transactions
Issue
11
Publish Date
2004
Start Page
1696
End Page
1702
DOI
10.1039/b400818a

A no-laminectomy spinal cord compression injury model in mice.

The purpose of this study was to develop a minimally invasive recovery model of spinal cord injury in the C57Bl/6J mouse. Without laminectomy, the epidural space was exposed by disruption of the T10-T11 interspinous ligament. Perpendicular to the rostral-caudal axis of the spine, a 1.5-mm silicone tube (O.D. 0.047 in.) was placed in the T11 epidural space. Prior to placement, a suture was passed through the tube allowing withdrawal of the tube after discontinuation of anesthesia. After 1, 30, 60, or 120 min (n = 5-8) of spinal cord compression (SCC), the tube was withdrawn. Neurological function was measured at 1, 3, 7, and 14 days after injury followed by histologic analysis. BBB locomotor score, rotarod latency, and screen grasping were worsened in a SCC duration-dependent manner (p < 0.0001). With increasing SCC duration, the number of histologically normal neurons in the ventral horns decreased (p < 0.0001) while the cross-sectional area of spinal cord with pancellular necrosis increased (p < 0.0001). Increased duration of SCC caused progressive rostral-caudal spread of histologic damage. The results indicate that this is a simple, reliable model with neurologic and histologic injury highly dependent on SCC duration. This model may be useful for study of spinal cord injury in genetically modified mice in the absence of anesthetic confounds while leaving the vertebral column intact.

Authors
Sheng, H; Wang, H; Homi, HM; Spasojevic, I; Batinic-Haberle, I; Pearlstein, RD; Warner, DS
MLA Citation
Sheng, H, Wang, H, Homi, HM, Spasojevic, I, Batinic-Haberle, I, Pearlstein, RD, and Warner, DS. "A no-laminectomy spinal cord compression injury model in mice." J Neurotrauma 21.5 (May 2004): 595-603.
PMID
15165367
Source
pubmed
Published In
Journal of Neurotrauma
Volume
21
Issue
5
Publish Date
2004
Start Page
595
End Page
603
DOI
10.1089/089771504774129928

Flavin-dependent antioxidant properties of a new series of meso-N,N′-dialkyl-imidazolium substituted manganese(III) porphyrins

A number of synthetic manganese complexes exhibit both in vitro and in vivo catalytic antioxidant activities. This study reports that the antioxidant potencies of a new series of meso-N,N′-dialkyl-imidazolium substituted manganese(III) porphyrins are dependent, in part, on their ability to redox cycle with endogenous flavin-dependent oxidoreductases. Inhibition of lipid peroxidation activities of these novel cationic porphyrins was compared using rat brain homogenate as a source of lipids and endogenous oxidoreductases. Iron and ascorbate was used as initiators of lipid peroxidation, and two indices of lipid peroxidation (thiobarbituric acid reactive species (TBARS) and F 2-isoprostanes) were determined. All meso-N,N′-dialkyl- imidazolium substituted porphyrins tested were potent inhibitors of lipid peroxidation with IC50 ranging from 0.1 to 34μM with a metal-dependent potency of Mn(III)≫Co(III)>Zn(II). A flavin-dependent oxidoreductase antioxidant process was supported by the ability of the diphenyleneiodonium chloride (DPI, a flavoenzyme inhibitor) to decrease the potency of Mn-porphyrins in the lipid peroxidation model and that Mn-porphyrins stimulate NADPH oxidation in rat brain homogenates. These data suggest that metalloporphyrins may have differential antioxidant effects in tissues due to the presence or absence of flavin-dependent oxidoreductases. © 2003 Elsevier Inc. All rights reserved.

Authors
Kachadourian, R; Johnson, CA; Min, E; Spasojevic, I; Day, BJ
MLA Citation
Kachadourian, R, Johnson, CA, Min, E, Spasojevic, I, and Day, BJ. "Flavin-dependent antioxidant properties of a new series of meso-N,N′-dialkyl-imidazolium substituted manganese(III) porphyrins." Biochemical Pharmacology 67.1 (2004): 77-85.
PMID
14667930
Source
scival
Published In
Biochemical Pharmacology
Volume
67
Issue
1
Publish Date
2004
Start Page
77
End Page
85
DOI
10.1016/j.bcp.2003.08.036

Electrostatic contribution in the catalysis of O2*- dismutation by superoxide dismutase mimics. MnIIITE-2-PyP5+ versus MnIIIBr8T-2-PyP+.

The Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) is a potent superoxide dismutase (SOD) mimic in vitro and was beneficial in rodent models of oxidative stress pathologies. Its high activity has been ascribed to both the favorable redox potential of its metal center and to the electrostatic facilitation assured by the four positive charges encircling the metal center. Its comparison with the non-alkylated, singly charged analogue Mn(III) beta-octabromo meso-tetrakis(2-pyridyl)porphyrin (Mn(III)Br(8)T-2-PyP(+)) enabled us to evaluate the electrostatic contribution to the catalysis of O(2)() dismutation. Both compounds exhibit nearly identical metal-centered redox potential for Mn(III)/Mn(II) redox couple: +228 mV for Mn(III)TE-2-PyP(5+) and +219 mV versus NHE for Mn(III)Br(8)T-2-PyP(+). The eight electron-withdrawing beta pyrrolic bromines contribute equally to the redox properties of the parent Mn(III)T-2-PyP(+) as do four quaternized cationic meso ortho pyridyl nitrogens. However, the SOD-like activity of the highly charged Mn(III)TE-2-PyP(5+) is >100-fold higher (log k(cat) = 7.76) than that of the singly charged Mn(III)Br(8)T-2-PyP(+) (log k(cat) = 5.63). The kinetic salt effect showed that the catalytic rate constants of the Mn(III)TE-2-PyP(5+) and of its methyl analogue, Mn(III)TM-2-PyP(5+), are exactly 5-fold more sensitive to ionic strength than is the k(cat) of Mn(III)Br(8)T-2-PyP(+), which parallels the charge ratio of these compounds. Interestingly, only a small effect of ionic strength on the rate constant was found in the case of penta-charged para (Mn(III)TM-4-PyP(5+)) and meta isomers (Mn(III)TM-3-PyP(5+)), indicating that the placement of the positive charges in the close proximity of the metal center (ortho position) is essential for the electrostatic facilitation of O(2)() dismutation.

Authors
Spasojevic, I; Batinic-Haberle, I; Reboucas, JS; Idemori, YM; Fridovich, I
MLA Citation
Spasojevic, I, Batinic-Haberle, I, Reboucas, JS, Idemori, YM, and Fridovich, I. "Electrostatic contribution in the catalysis of O2*- dismutation by superoxide dismutase mimics. MnIIITE-2-PyP5+ versus MnIIIBr8T-2-PyP+." J Biol Chem 278.9 (February 28, 2003): 6831-6837.
PMID
12475974
Source
pubmed
Published In
The Journal of biological chemistry
Volume
278
Issue
9
Publish Date
2003
Start Page
6831
End Page
6837
DOI
10.1074/jbc.M211346200

Meso tetrakis ortho-, meta-, and para-n-alkylpyridinioporphyrins: Kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation

The relative reactivities of the tetrakis(N-alkylpyridinium-X-yl)-porphyrins where X = 4 (alkyl = methyl, ethyl, n-propyl), X = 3 (methyl), and X = 2 (methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl) were studied in aqueous solution. From the ionic strength dependence of the metalation rate constants, the effective charge of a particular cationic porphyrin was usually larger when copper(II) rather than zinc(II) was the reactant. The kinetics of ZnOH+ incorporation and the acid catalyzed removal of zinc from the porphyrins in 1.0 M HCl were also studied. In general, the more basic 4- (para-) and 3- (meta-) isomers were the most reactive, followed by the less basic 2-(ortho-) methyl to n-butyl derivatives, with the lipophilic ortho n-hexyl and n-octyl porphyrins the least reactive. Copyright © 2003 Society of Porphyrins & Phthalocyanines.

Authors
Hambright, P; Batinić-Haberle, I; Spasojević, I
MLA Citation
Hambright, P, Batinić-Haberle, I, and Spasojević, I. "Meso tetrakis ortho-, meta-, and para-n-alkylpyridinioporphyrins: Kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation." Journal of Porphyrins and Phthalocyanines 7.3 (2003): 139-146.
Source
scival
Published In
Journal of Porphyrins and Phthalocyanines
Volume
7
Issue
3
Publish Date
2003
Start Page
139
End Page
146

Rotational isomers of N-alkylpyridylporphyrins and their metal complexes. HPLC separation, (1)H NMR and X-ray structural characterization, electrochemistry, and catalysis of O(2)(.-) disproportionation.

Rotational (atropo-) isomers of Mn(III) meso-tetrakis(N-alkylpyridinium-2-yl)porphyrins and corresponding metal-free porphyrin ligands (where alkyl is methyl, ethyl, n-butyl, n-hexyl) and Zn(II) meso-tetrakis(N-methyl(ethyl,n-hexyl)pyridinium-2-yl)porphyrins were separated and isolated by reverse-phase HPLC. The identity of the rotational isomers of metal-free meso-tetrakis(N-methylpyridinium-2-yl)porphyrin was established by (1)H NMR spectra and by the crystal structure of the fastest eluting fraction (R(f) = 7.7%, R(w) = 9.2%, P2(1)/c, Z = 8, a = 14.2846(15) A, b = 22.2158(24) A, c = 29.369(3) A, beta = 95.374(2) degrees ) which, in accordance with (1)H NMR interpretation, proved to be the alphabetaalphabeta isomer. This result, together with elution intensity patterns, was used to identify the fractions of other Mn(III)-porphyrins, Zn(II)-porphyrins, and corresponding metal-free ligands in the series. All of the atropoisomers were inert toward isomerization which was not observable for 30 days at room temperature and reached only 50% in 16 days at 90 degrees C in the case of the Mn(III)-ethyl analogue. However, a complete freeze-dry removal of the mobile phase from the HPLC fractions caused an almost 100% isomerization. The Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, as a mixture of atropoisomers (AEOL-10113), has been shown to offer protection in oxidative stress injury ascribed to its high reactivity toward superoxide (k(cat) = 5.8 x 10(7) M(-1) s(-1)) as a consequence of its favorable redox potential (E(1/2) = +228 mV vs NHE). In this work, the atropoisomers were found to have similar redox potentials ranging from +240 to +220 mV, to be similarly potent catalysts of O(2)(.-) disproportionation (dismutation), with k(cat) ranging from 5.5 x 10(7) to 6.8 x 10(7) M(-1) s(-1), and not to preferentially bind to biological tissue.

Authors
Spasojević, I; Menzeleev, R; White, PS; Fridovich, I
MLA Citation
Spasojević, I, Menzeleev, R, White, PS, and Fridovich, I. "Rotational isomers of N-alkylpyridylporphyrins and their metal complexes. HPLC separation, (1)H NMR and X-ray structural characterization, electrochemistry, and catalysis of O(2)(.-) disproportionation." Inorg Chem 41.22 (November 4, 2002): 5874-5881.
PMID
12401096
Source
pubmed
Published In
Inorganic Chemistry
Volume
41
Issue
22
Publish Date
2002
Start Page
5874
End Page
5881

A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury.

Radiation therapy (RT) is an important therapeutic modality in the treatment of thoracic tumors. The maximum doses to these tumors are often limited by the radiation tolerance of lung tissues. Lung injury from ionizing radiation is believed to be a consequence of oxidative stress and a cascade of cytokine activity. Superoxide dismutase (SOD) is a key enzyme in cellular defenses against oxidative damage. The objective of this study was to determine whether the SOD mimetic AEOL 10113 [manganese (III) mesotetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP(5+))] increases the tolerance of lung to ionizing radiation. AEOL 10113 was able to significantly reduce the severity of RT-induced lung injury. This was strongly supported with histopathology results and measurements of collagen deposition (hydroxyproline content). There was a significant reduction in the plasma level of the profibrogenic cytokine transforming growth factor-beta (TGF-beta) in the group of rats receiving RT + AEOL 10113. In conclusion, the novel SOD mimetic, AEOL 10113, demonstrates a significant protective effect from radiation-induced lung injury.

Authors
Vujaskovic, Z; Batinic-Haberle, I; Rabbani, ZN; Feng, Q-F; Kang, SK; Spasojevic, I; Samulski, TV; Fridovich, I; Dewhirst, MW; Anscher, MS
MLA Citation
Vujaskovic, Z, Batinic-Haberle, I, Rabbani, ZN, Feng, Q-F, Kang, SK, Spasojevic, I, Samulski, TV, Fridovich, I, Dewhirst, MW, and Anscher, MS. "A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury." Free Radic Biol Med 33.6 (September 15, 2002): 857-863.
PMID
12208373
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
33
Issue
6
Publish Date
2002
Start Page
857
End Page
863

Isomeric N-alkylpyridylporphyrins and their Zn(II) complexes: inactive as SOD mimics but powerful photosensitizers.

The ortho, meta, and para isomers of cationic N-alkylpyridylporphyrins and their Zn(II) complexes were compared in terms of their photodynamic properties. The ortho Zn(II) complex was found to be the most efficient in causing photooxidation of NADH in vitro. In Escherichia coli, however, the para and meta isomers were better photosensitizers than their ortho analogs. The lower potency of the ortho compound in vivo seems to be due to its lower intracellular concentration. All porphyrins tested were more efficient in killing E. coli and in photooxidizing NADH than the hematoporphyrin derivative. Antibiotic resistance did not affect the photokill, which implies that the cationic N-alkylpyridylporphyrins, as their Zn(II) complexes, can be used as bactericidal agents against antibiotic-resistant strains of gram-negative bacteria.

Authors
Benov, L; Batinić-Haberle, I; Spasojević, I; Fridovich, I
MLA Citation
Benov, L, Batinić-Haberle, I, Spasojević, I, and Fridovich, I. "Isomeric N-alkylpyridylporphyrins and their Zn(II) complexes: inactive as SOD mimics but powerful photosensitizers." Arch Biochem Biophys 402.2 (June 15, 2002): 159-165.
PMID
12051659
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
402
Issue
2
Publish Date
2002
Start Page
159
End Page
165
DOI
10.1016/S0003-9861(02)00062-0

Thermodynamics, kinetics, and mechanism of the stepwise dissociation and formation of Tris(L-lysinehydroxamato)iron(III) in aqueous acid.

pK(a) values for the hydroxamic acid, alpha-NH(3)(+), and epsilon-NH(3)(+) groups of L-lysinehydroxamic acid (LyHA, H(3)L(2+)) were found to be 6.87, 8.89, and 10.76, respectively, in aqueous solution (I = 0.1 M, NaClO(4)) at 25 degrees C. O,O coordination to Fe(III) by LyHA is supported by H(+) stoichiometry, UV-vis spectral shifts, and a shift in nu(CO) from 1648 to 1592 cm(-1) upon formation of mono(L-lysinehydroxamato)tetra(aquo)iron(III) (Fe(H(2)L)(H(2)O)(4)(4+)). The stepwise formation of tris(L-lysinehydroxamato)iron(III) from Fe(H(2)O)(6)(3+) and H(3)L(2+) was characterized by spectrophotometric titration, and the values for log beta(1), log beta(2), and log beta(3) are 6.80(9), 12.4(2), and 16.1(2), respectively, at 25 degrees C and I = 2.0 M (NaClO(4)). Stopped-flow spectrophotometry was used to study the proton-driven stepwise ligand dissociation kinetics of tris(L-lysinehydroxamato)iron(III) at 25 degrees C and I = 2.0 M (HClO(4)/NaClO(4)). Defining k(n) and k(-n) as the stepwise ligand dissociation and association rate constants and n as the number of bound LyHA ligands, k(3), k(-3), k(2), k(-2), k(1), and k(-1) are 3.0 x 10(4), 2.4 x 10(1), 3.9 x 10(2), 1.9 x 10(1), 1.4 x 10(-1), and 1.2 x 10(-1) M(-1) s(-1), respectively. These rate and equilibrium constants are compared with corresponding constants for Fe(III) complexes of acetohydroxamic acid (AHA) and N-methylacetohydroxamic acid (NMAHA) in the form of a linear free energy relationship. The role of electrostatics in these complexation reactions to form the highly charged Fe(LyHA)(3)(6+) species is discussed, and an interchange mechanism mediated by charge repulsion is presented. The reduction potential for tris(L-lysinehydroxamato)iron(III) is -214 mV (vs. NHE), and a comparison to other hydroxamic acid complexes of Fe(III) is made through a correlation between E(1/2) and pFe.

Authors
Wirgau, JI; Spasojević, I; Boukhalfa, H; Batinić-Haberle, I; Crumbliss, AL
MLA Citation
Wirgau, JI, Spasojević, I, Boukhalfa, H, Batinić-Haberle, I, and Crumbliss, AL. "Thermodynamics, kinetics, and mechanism of the stepwise dissociation and formation of Tris(L-lysinehydroxamato)iron(III) in aqueous acid." Inorg Chem 41.6 (March 25, 2002): 1464-1473.
PMID
11896715
Source
pubmed
Published In
Inorganic Chemistry
Volume
41
Issue
6
Publish Date
2002
Start Page
1464
End Page
1473

Manganese(III) meso-tetrakis(ortho-N-alkylpyridyl)porphyrins. Synthesis, characterization, and catalysis of O2/·- dismutation

A series of ortho isomers of meso-tetrakis(N-alkylpyridyl)porphyrins (alkyl being methyl, ethyl, n-propyl, n-butyl, n-hexyl, and n-octyl) and their Mn(III) complexes were synthesized and characterized by elemental analysis, uv/vis spectroscopy, electrospray ionization mass spectrometry and electrochemistry. An increase in the number of carbon atoms in the alkyl chains from 1 to 8 is accompanied by an increase in: (a) lipophilicity, as measured by the chromatographic retention factor, Rf; (b) metal-centered redox potential, E1/2 from +220 to +367 mV vs. NHE, and (c) proton dissociation constant, pKa2 from 10.9 to 13.2. A linear correlation was found between E1/2 and Rf of the Mn(III) porphyrins and between the pKa2 and Rf of the metal-free compounds. As the porphyrins become increasingly more lipophilic, the decrease in hydration disfavors the creation of charge, while enhancing the electron-withdrawing effect of the positively charged pyridyl nitrogen atoms. Consequently, E1/2 increases linearly with the increase in pKa2, a trend in porphyrin basicity opposite from the one we previously reported for other water-soluble Mn(III) porphyrins. All of these Mn(III) porphyrins are potent catalysts for superoxide dismutation (disproportionation). Despite the favorable increase of E1/2 with the increase in chain length, the catalytic rate constant decreases from methyl (log kcat = 7.79) to n-butyl, and then increases such that the n-octyl is as potent a SOD mimic as are the methyl and ethyl compounds. The observed behavior originates from an interplay of hydration and steric effects that modulate electronic effects.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Hambright, P; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Hambright, P, and Fridovich, I. "Manganese(III) meso-tetrakis(ortho-N-alkylpyridyl)porphyrins. Synthesis, characterization, and catalysis of O2/·- dismutation." Journal of the Chemical Society, Dalton Transactions 13 (2002): 2689-2696.
Source
scival
Published In
Dalton : an international journal of inorganic chemistry.
Issue
13
Publish Date
2002
Start Page
2689
End Page
2696

Synthesis, ligand pK(a), and Fe(III) complexation constants for a series of bipodal dihydroxamic acids.

The synthesis of four bipodal dihydroxamic acids containing an apical C atom and amide linkages is described, where Ia,b represent "normal" and "retro" hydroxamate isomers: (R)CH[C(=O)NH(CH(2))(2)NHC(=O)(CH(2))(n)()R'](2) (Ia, R = CH(3), R' = N(OH)(C=O)CH(3), n = 2; Ib, R = CH(3), R' = (C=O)N(OH)CH(3), n = 2; Ic, R = CH(3), R' = (C=O)N(OH)CH(3), n = 3; Id, R = C(4)H(9), R' = (C=O)N(OH)CH(3), n = 2.). The pK(a1) and pK(a2) values in aqueous solution are reported, and some degree of cooperativity is noted. Complexation equilibria with Fe(aq)(3+) are described, and values for stepwise and overall equilibrium constants are reported. log beta(230) values for Ia-d are 59.22, 59.45, 58.91, and 58.46, slightly lower than for rhodotorulic acid, although the pFe values for the synthetic siderophores are comparable to that for rhodotorulic acid.

Authors
Nguyen-Van-Duong, MK; Guillot, V; Nicolas, L; Gaudemer, A; Lowry, L; Spasojević, I; Crumbliss, AL
MLA Citation
Nguyen-Van-Duong, MK, Guillot, V, Nicolas, L, Gaudemer, A, Lowry, L, Spasojević, I, and Crumbliss, AL. "Synthesis, ligand pK(a), and Fe(III) complexation constants for a series of bipodal dihydroxamic acids." Inorg Chem 40.23 (November 5, 2001): 5948-5953.
PMID
11681910
Source
pubmed
Published In
Inorganic Chemistry
Volume
40
Issue
23
Publish Date
2001
Start Page
5948
End Page
5953

Manganese(III) biliverdin IX dimethyl ester: a powerful catalytic scavenger of superoxide employing the Mn(III)/Mn(IV) redox couple.

A manganese(III) complex of biliverdin IX dimethyl ester, (MnIIIBVDME)2, was prepared and characterized by elemental analysis, UV/vis spectroscopy, cyclic voltammetry, chronocoulometry, electrospray mass spectrometry, freezing-point depression, magnetic susceptibility, and catalytic dismuting of superoxide anion (O2.-). In a dimeric conformation each trivalent manganese is bound to four pyrrolic nitrogens of one biliverdin dimethyl ester molecule and to the enolic oxygen of another molecule. This type of coordination stabilizes the +4 metal oxidation state, whereby the +3/+4 redox cycling of the manganese in aqueous medium was found to be at E1/2 = +0.45 V vs NHE. This potential allows the Mn(III)/Mn(IV) couple to efficiently catalyze the dismutation of O2.- with the catalytic rate constant of kcat = 5.0 x 10(7) M-1 s-1 (concentration calculated per manganese) obtained by cytochrome c assay at pH 7.8 and 25 degrees C. The fifth coordination site of the manganese is occupied by an enolic oxygen, which precludes binding of NO., thus enhancing the specificity of the metal center toward O2.-. For the same reason the (MnIIIBVDME)2 is resistant to attack by H2O2. The compound also proved to be an efficient SOD mimic in vivo, facilitating the aerobic growth of SOD-deficient Escherichia coli.

Authors
Spasojević, I; Batinić-Haberle, I; Stevens, RD; Hambright, P; Thorpe, AN; Grodkowski, J; Neta, P; Fridovich, I
MLA Citation
Spasojević, I, Batinić-Haberle, I, Stevens, RD, Hambright, P, Thorpe, AN, Grodkowski, J, Neta, P, and Fridovich, I. "Manganese(III) biliverdin IX dimethyl ester: a powerful catalytic scavenger of superoxide employing the Mn(III)/Mn(IV) redox couple." Inorg Chem 40.4 (February 12, 2001): 726-739.
PMID
11225116
Source
pubmed
Published In
Inorganic Chemistry
Volume
40
Issue
4
Publish Date
2001
Start Page
726
End Page
739

Aqueous solution speciation of Fe(III) complexes with dihydroxamate siderophores alcaligin and rhodotorulic acid and synthetic analogues using electrospray ionization mass spectrometry.

Aqueous solutions of Fe3+ complexes of cyclic (alcaligin) and linear (rhodotorulic acid) dihydroxamate siderophores and synthetic linear eight-carbon-chain and two-carbon-chain dihydroxamic acids ([CH3N(OH)C=O)]2(CH2)n; H2Ln; n = 2 and 8) were investigated by electrospray ionization mass spectrometry (ESI-MS). Information was obtained relevant to the structure and the speciation of various Fe(III)-dihydroxamate complexes present in aqueous solution by (1) comparing different ionization techniques (ESI and FAB), (2) altering the experimental parameters (Fe3+/ligand ratio, pH, cone voltage), (3) using high-stability hexacoordinated Fe(III) siderophore complex mixtures (ferrioxamine B/ferrioxamine E) as a calibrant to quantify intrinsically neutral (H+ clustered or protonated) and intrinsically charged complexes, and (4) using mixed-metal complexes containing Fe3+, Ga3+, and Al3+. These results illustrate that for all dihydroxamic acid ligands investigated multiple tris- and bis-chelated mono- and di-Fe(III) species are present in relative concentrations that depend on the pH and Fe/L ratio.

Authors
Spasojević, I; Boukhalfa, H; Stevens, RD; Crumbliss, AL
MLA Citation
Spasojević, I, Boukhalfa, H, Stevens, RD, and Crumbliss, AL. "Aqueous solution speciation of Fe(III) complexes with dihydroxamate siderophores alcaligin and rhodotorulic acid and synthetic analogues using electrospray ionization mass spectrometry." Inorg Chem 40.1 (January 1, 2001): 49-58.
PMID
11195388
Source
pubmed
Published In
Inorganic Chemistry
Volume
40
Issue
1
Publish Date
2001
Start Page
49
End Page
58

Nitrosylation of manganese(II) tetrakis(N-ethylpyridinium-2-yl)porphyrin: a simple and sensitive spectrophotometric assay for nitric oxide.

Reaction between NO(*) and manganese tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) was investigated at 25 degrees C. At high excess of NO(*) (1.5 mM) the reaction with the oxidized, air-stable form Mn(III)TE-2-PyP(5+) (5 microM), proceeds very slowly (t(1/2) congruent with 60 min). The presence of excess ascorbate (1 mM) produces the reduced form, Mn(II)TE-2-PyP(4+), which reacts with NO(*) stoichiometrically and in the time of mixing (k congruent with 1 x 10(6) M(-1) s(-1)). The high rate of formation and the stability of the product, Mn(II)TE-2-PyP(NO)(4+) (¿Mn(NO)¿(6)), make the reaction outcompete the reaction of NO(*) with O(2). Our in vitro measurements show a linear absorbance response upon addition of NO to a PBS, pH 7.4, solution containing an excess of ascorbate over Mn(III)TE-2-PyP(5+). Thus, the observed interactions can be the basis of a convenient and sensitive spectrophotometric assay for NO(*). Also, it may have important implications for the in vivo behavior of Mn(III)TE-2-PyP(5+) which is currently exploited as a possible therapeutic agent for various oxygen-radical related disorders.

Authors
Spasojevic, I; Batinic-Haberle, I; Fridovich, I
MLA Citation
Spasojevic, I, Batinic-Haberle, I, and Fridovich, I. "Nitrosylation of manganese(II) tetrakis(N-ethylpyridinium-2-yl)porphyrin: a simple and sensitive spectrophotometric assay for nitric oxide." Nitric Oxide 4.5 (October 2000): 526-533.
PMID
11020341
Source
pubmed
Published In
Nitric Oxide: Biology and Chemistry
Volume
4
Issue
5
Publish Date
2000
Start Page
526
End Page
533
DOI
10.1006/niox.2000.0303

Lucigenin: redox potential in aqueous media and redox cycling with O-(2) production.

The use of lucigenin luminescence as a measure of ¿O-(2) has been questioned because lucigenin has been shown to be capable of mediating the production of O-(2). This being the case, lucigenin can signal the presence of O-(2) even in systems not producing it in the absence of lucigenin. The reduction potential of lucigenin should be in accord with its ability to mediate O-(2) production; but it has not heretofore been measured in aqueous media. The problems facing such measurement are the insolubility of the divalently reduced form, which deposits on the electrode, and the slow conformational transition that follows the second electron transfer and which interferes with reversibility. We have now used rapid scan cyclic voltammetry to determine that the reduction potential for lucigenin is -0.14 +/- 0.02 V versus the normal hydrogen electrode. This value applies to both the first and the second electron transfers to lucigenin and it is in accord with the facile mediation of O-(2) production by this compound.

Authors
Spasojevic, I; Liochev, SI; Fridovich, I
MLA Citation
Spasojevic, I, Liochev, SI, and Fridovich, I. "Lucigenin: redox potential in aqueous media and redox cycling with O-(2) production." Arch Biochem Biophys 373.2 (January 15, 2000): 447-450.
PMID
10620371
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
373
Issue
2
Publish Date
2000
Start Page
447
End Page
450
DOI
10.1006/abbi.1999.1579

Catalytic scavenging of peroxynitrite by isomeric Mn(III) N-methylpyridylporphyrins in the presence of reductants.

Three isomers of manganese(III) 5,10,15, 20-tetrakis(N-methylpyridyl)porphyrin (MnTMPyP) were evaluated for their reaction with peroxynitrite. The Mn(III) complexes reacted with peroxynitrite anion with rate constants of 1.85 x 10(7), 3.82 x 10(6), and 4.33 x 10(6) M(-1) s(-1) at 37 degrees C for MnTM-2-PyP, MnTM-3-PyP, and MnTM-4-PyP, respectively, to yield the corresponding oxo-Mn(IV) complexes. Throughout the pH range from 5 to 8.5, MnTM-2-PyP reacted 5-fold faster than the other two isomers. The oxo-Mn(IV) complexes could in turn be reduced by glutathione, ascorbate, urate, or oxidize tyrosine. The rate constants for the reduction of the oxo-Mn(IV) complexes ranged from >10(7) M(-1) s(-1) for ascorbate to 10(3)-10(4) M(-1) s(-1) for tyrosine and glutathione. Cyclic voltammetry experiments show that there is no significant difference in the E1/2 of the Mn(IV)/Mn(III) couple; thus, the differential reactivity of the three isomeric complexes is interpreted in terms of electrostatic and steric effects. Micromolar concentrations of MnTM-2-PyP compete well with millimolar CO2 at reacting with ONOO-, and it can even scavenge a fraction of the ONOOCO2- that is formed. By being rapidly oxidized by ONOO- and ONOOCO2- and reduced by antioxidants such as ascorbate, urate, and glutathione, these manganese porphyrins, and especially MnTM-2-PyP, can redirect the oxidative potential of peroxynitrite toward natural antioxidants, thus protecting more critical targets such as proteins and nucleic acids.

Authors
Ferrer-Sueta, G; Batinić-Haberle, I; Spasojević, I; Fridovich, I; Radi, R
MLA Citation
Ferrer-Sueta, G, Batinić-Haberle, I, Spasojević, I, Fridovich, I, and Radi, R. "Catalytic scavenging of peroxynitrite by isomeric Mn(III) N-methylpyridylporphyrins in the presence of reductants." Chem Res Toxicol 12.5 (May 1999): 442-449.
PMID
10328755
Source
pubmed
Published In
Chemical Research in Toxicology
Volume
12
Issue
5
Publish Date
1999
Start Page
442
End Page
449
DOI
10.1021/tx980245d

Electrochemical Behavior of the Fe(III) Complexes of the Cyclic Hydroxamate Siderophores Alcaligin and Desferrioxamine E.

The redox behavior of Fe(III) complexes of the cyclic hydroxamate siderophores alcaligin and desferrioxamine E was investigated by cyclic voltammetry. The limiting, pH independent redox potential (E(1/2) vs NHE) is -446 mV for alcaligin above pH 9 and -477 mV for ferrioxamine E above pH 7.5. At lower pH values, the redox potential for both complexes shifts positive, with a loss of voltammetric reversibility which is interpreted to be the consequence of a secondary dissociation of Fe(II) from the reduced form of the complexes. These observations are of biological importance, since they suggest the possibility of a reductive mechanism in microbial cells which utilize these siderophores to acquire Fe. For comparison purposes, cyclic voltammograms were obtained for Fe(III) complexes with trihydroxamic acids of cyclic (ferrioxamine E) and linear (ferrioxamine B) structures, with dihydroxamic acids of cyclic (alcaligin) and linear (rhodotorulic and sebacic acids) structures, and with monohydroxamic acids (acetohydroxamic and N-methylacetohydroxamic acids) at identical conditions. The observed redox potentials allow us to estimate the overall stability constants for fully coordinated Fe(II) complexes as log beta(II)(Fe(2)alcaligin(3)) = 24.6 and log beta(II)(ferrioxamine E) = 12.1. A linear correlation between E(1/2) and pM was found, and the basis for this relationship is discussed in terms of structural (denticity and cyclic/acyclic) and electronic differences among the {alkyl-NOH-CO-alkyl} type of hydroxamic acid ligands studied.

Authors
Spasojevic, I; Armstrong, SK; Brickman, TJ; Crumbliss, AL
MLA Citation
Spasojevic, I, Armstrong, SK, Brickman, TJ, and Crumbliss, AL. "Electrochemical Behavior of the Fe(III) Complexes of the Cyclic Hydroxamate Siderophores Alcaligin and Desferrioxamine E." Inorg Chem 38.3 (February 8, 1999): 449-454.
PMID
11673947
Source
pubmed
Published In
Inorganic Chemistry
Volume
38
Issue
3
Publish Date
1999
Start Page
449
End Page
454

Relationship among redox potentials, proton dissociation constants of pyrrolic nitrogens, and in vivo and in vitro superoxide dismutating activities of manganese(III) and iron(III) water-soluble porphyrins

The log k cat values for the dismutation of O 2- by a series of monohydroxoiron(III) and aquamanganese(III) porphyrins, including ortho, meta, and para isomers of 5,10,15,20-tetrakis(N-alkylpyridiniumyl)porphyrins, were found to vary linearly with the metal-centered redox potentials (E 1/2) for the M(III)/M(II) couple. Each 120 mV increase in E 1/2 imparted a 10-fold increase in k cat. The observed behavior is in accord with the Marcus equation for outer-sphere electron-transfer reactions, suggesting that the same mechanism is operative for iron and manganese porphyrins. The Marcus plot enabled us to estimate the self-exchange rate constants of monohydroxoiron porphyrins to be ∼1 order of magnitude higher than those of aquamanganese porphyrins. Furthermore, E 1/2 values for all of the metalloporhyrins investigated were linearly related to the acid dissociation constants (pK a3) of the pyrrolic nitrogen of the metal-free porphyrins, indicating that either E 1/2, or the more readily measured pK a3, may be useful in predicting SOD activity in vitro. The most potent compounds investigated, with respect to SOD activity, are those of the ortho N-alkylpyridiniumyl series. Ortho N-alkylpyridiniumyl groups are more electron withdrawing than are the meta or para groups, thus imparting a more positive redox potential and a correspondingly higher SOD activity. Sufficiently positive potentials, or sufficiently low pK a3 values, are necessary for useful SOD activity, but so is the absence of toxicity. Despite their favorable redox potentials and SOD activities, all Fe(III) porphyrins investigated were toxic to Escherichia coli under both aerobic and anaerobic conditions and to both SOD-deficient and SOD-proficient strains. Only the ortho and meta manganese isomers of the N-alkylpyridiniumyl series (Mn III-TE-2-PyP 5+, Mn IIITM-2-PyP 5+ and Mn IIITM-3-PyP 5+) significantly protected SOD-deficient E. coli and allowed growth in an aerobic minimal medium. In previous work, we established that the lower toxicity of these compounds is due to diminished ability to bind to nucleic acids. The Mn(III) complexes are preferable to the Fe(III) complexes for SOD mimics possibly due to a lower tendency for axial ligation. We propose E 1/2 ≥ +0.05 V vs NHE and/or pK a3 ≤ 2.0 as necessary requirements for Mn porphyrins to be considered useful SOD mimics. © 1999 American Chemical Society.

Authors
Batinić-Haberle, I; Spasojević, I; Hambright, P; Benov, L; Cmmbliss, AL; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Hambright, P, Benov, L, Cmmbliss, AL, and Fridovich, I. "Relationship among redox potentials, proton dissociation constants of pyrrolic nitrogens, and in vivo and in vitro superoxide dismutating activities of manganese(III) and iron(III) water-soluble porphyrins." Inorganic Chemistry 38.18 (1999): 4011-4022.
Source
scival
Published In
Inorganic Chemistry
Volume
38
Issue
18
Publish Date
1999
Start Page
4011
End Page
4022

PH induced active ("Uphill") liquid membrane transport of ferrioxamine B by the ionizable ionophore lasalocid

Authors
Spasojević, I; Crumbliss, AL
MLA Citation
Spasojević, I, and Crumbliss, AL. "PH induced active ("Uphill") liquid membrane transport of ferrioxamine B by the ionizable ionophore lasalocid." Inorganic Chemistry 38.13 (1999): 3248-3250.
Source
scival
Published In
Inorganic Chemistry
Volume
38
Issue
13
Publish Date
1999
Start Page
3248
End Page
3250

The ortho effect makes manganese(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin a powerful and potentially useful superoxide dismutase mimic.

The ortho, meta, and para isomers of manganese(III) 5,10,15, 20-tetrakis(N-methylpyridyl)porphyrin, MnTM-2-PyP5+, MnTM-3-PyP5+, and MnTM-4-PyP5+, respectively, were analyzed in terms of their superoxide dismutase (SOD) activity in vitro and in vivo. The impact of their interaction with DNA and RNA on the SOD activity in vivo and in vitro has also been analyzed. Differences in their behavior are due to the combined steric and electrostatic factors. In vitro catalytic activities are closely related to their redox potentials. The half-wave potentials (E1/2) are +0.220 mV, +0.052 mV, and +0.060 V versus normal hydrogen electrode, whereas the rates of dismutation (kcat) are 6.0 x 10(7), 4.1 x 10(6), and 3.8 x 10(6) M-1 s-1 for the ortho, meta, and para isomers, respectively. However, the in vitro activity is not a sufficient predictor of in vivo efficacy. The ortho and meta isomers, although of significantly different in vitro SOD activities, have fairly close in vivo SOD efficacy due to their similarly weak interactions with DNA. In contrast, due to a higher degree of interaction with DNA, the para isomer inhibited growth of SOD-deficient Escherichia coli.

Authors
Batinić-Haberle, I; Benov, L; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Benov, L, Spasojević, I, and Fridovich, I. "The ortho effect makes manganese(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin a powerful and potentially useful superoxide dismutase mimic." J Biol Chem 273.38 (September 18, 1998): 24521-24528.
PMID
9733746
Source
pubmed
Published In
The Journal of biological chemistry
Volume
273
Issue
38
Publish Date
1998
Start Page
24521
End Page
24528

Lariat Ether Carboxylic Acids as Ionizable Hosts in the Second Coordination Sphere of the Siderophore Ferrioxamine B in Chloroform

A new series of lariat ether carboxylic acids (LnCOOH) was synthesized with different lengths of side arm (6, 9, and 12 atom spacers between the benzo-18-crown-6 crown ether ring and the carboxylic acid functional group). These lariat ethers were used as neutral and anionic hosts for the molecular recognition of the cationic siderophore, ferrioxamine B. Lariat ether pKa values were determined by potentiometric titration in 50% methanol (v/v) to be in the range 5.23-5.32. Molecular recognition of ferrioxamine B occurs through second-sphere complexation of the pendant protonated amine (-(CH2)5NH3+) by the lariat ether cavity, utilizing an ion-dipole host-guest interaction to form a supramolecular assembly in wet chloroform. At conditions where the pendant carboxylic acid side arm is not ionized (pH = 3.2), the lariat ethers behave as the parent unsubstituted crown ether structure, benzo-18-crown-6 (B18C6). At pH conditions well above their pKa values, the lariat ether carboxylic acids function both as a host and as an internal counterion. The stability of this binary assembly, {FeHDFB+,LnCOO-}, is significantly increased (log Kapp = 4.85 for L12COO-) compared with that of the ternary assembly involving the protonated lariat ether, {FeHDFB+,LnCOOH,ClO4-} (log K = 3.26 for L12COOH), or the parent crown ether, {FeHDFB+,B18C6,ClO4-} (log K = 3.21). Stability was also observed to increase with the length of the side arm from 6 (log Kapp = 4.29) to 12 atom spacers (log Kapp = 4.85). We attribute this effect to the increased conformational freedom of the longer arm, which facilitates interaction between the protonated amine site and the carboxylate moiety.

Authors
Batinić-Haberle, I; Spasojević, I; Jang, Y; Bartsch, RA; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, Jang, Y, Bartsch, RA, and Crumbliss, AL. "Lariat Ether Carboxylic Acids as Ionizable Hosts in the Second Coordination Sphere of the Siderophore Ferrioxamine B in Chloroform." Inorganic Chemistry 37.7 (1998): 1438-1445.
Source
scival
Published In
Inorganic Chemistry
Volume
37
Issue
7
Publish Date
1998
Start Page
1438
End Page
1445

Bulk liquid membrane transport of ferrioxamine B by neutral and ionizable carriers

Bulk liquid membrane (BLM) transport of ferrioxamine B (FeHDFB+) across an artificial hydrophobia membrane facilitated by neutral and ionizable carriers was studied. Under controlled conditions, ferrioxamine B transport by neutral ionophores follows a simple theoretical model for a diffusion controlled process which predicts a linear dependence of flux upon aqueous-to-chloroform extraction constants. Unsubstituted 18C6 crown ether exhibits the best transport properties among the neutral carriers investigated with a flux of 1.4 × 10-10 mol s-1 cm-2. When transport of FeHDFB+, metal-free desferrioxamine B, H4DFB+, and AlHDFB+ mediated by DC18C6 crown ether was followed, a selectivity was observed with a ratio of measured relative fluxes of 5:3:1, respectively. An ionizable carrier lasalocid {6-[7-[5-ethyl-5-(5-ethyltetrahydro-5-hydroxy-6-methyl-2H-pyran-2-yl)tetrahydro- 3-methyl-2-furanyl]-4-hydroxy-3,5-dimethyl-6-oxonoyl]-2-hydroxy-3-methylbenzoic acid}, negatively charged at neutral pH, outperformed the crown ethers as a ferrioxamine B transporting agent. However, transport by ionizable carriers follows a different mechanism and occurs only when an electrolyte is present in the receiving phase. This requirement was exploited by designing a BLM experiment in which H4DFB+ acts as a counter cation at the receiving interface, whereby FeHDFB+ and H4DFB+ were transported in opposite directions in a synergistic fashion. When the ionizable salicylic acid moiety of lasalocid is transformed into an ester, lasalocid almost entirely loses its transporting properties. This suggests a co-operative mode of binding in which electrostatic recognition of the FeHDFB+ cation by lasalocid anion is a prerequisite for a subsequent encapsulation of the amine site in a host-guest fashion.

Authors
Spasojević, I; Crumbliss, AL
MLA Citation
Spasojević, I, and Crumbliss, AL. "Bulk liquid membrane transport of ferrioxamine B by neutral and ionizable carriers." Journal of the Chemical Society - Dalton Transactions 23 (1998): 4021-4027.
Source
scival
Published In
Journal- Chemical Society Dalton Transactions
Issue
23
Publish Date
1998
Start Page
4021
End Page
4027

A potent superoxide dismutase mimic: manganese beta-octabromo-meso-tetrakis-(N-methylpyridinium-4-yl) porphyrin.

Variously modified metalloporphyrins offer a promising route to stable and active mimics of superoxide dismutase (SOD). Here we explore bromination on the pyrroles as a means of increasing the redox potentials and the catalytic activities of the copper and manganese complexes of a cationic porphyrin. Mn(II) and Cu(II) octabrominated 5,10,15,20-tetrakis-(N-methylpyridinium-4-yl) porphyrin, Mn(II)OBTMPyP4+, and Cu(II)OBTMPyP4+ were prepared and characterized. The rate constants for the porphyrin-catalyzed dismutation of O2.- as determined from the inhibition of the cytochrome c reduction are k(cat) = 2.2 x 10(8) and 2.9 x 10(6) M(-1) s(-1), i.e., IC50 was calculated to be 12 nM and 0.88 microM, respectively. The metal-centered half-wave potential was E(1/2) = +0.48 V vs NHE for the manganese compound. Cu(II)OBTMPyP4+ proved to be extremely stable, while its Mn(II) analog has a moderate stability, log K = 8.08. Nevertheless, slow manganese dissociation from Mn(II)OBTMPyP4+ enabled the complex to persist and exhibit catalytic activity even at the nanomolar concentration level and at biological pH. The corresponding Mn(III)OBTMPyP5+ complex exhibited significantly increased stability, i.e., demetallation was not detected in the presence of a 400-fold molar excess of EDTA at micromolar porphyrin concentration and at pH 7.8. The beta-substituted manganese porphyrin facilitated the growth of a SOD-deficient strain of Escherichia coli when present at 0.05 microM but was toxic at 1.0 microM. The synthetic approach used in the case of manganese and copper compounds offers numerous possibilities whereby the interplay of the type and of the number of beta substituents on the porphyrin ring would hopefully lead to porphyrin compounds of increased stability, catalytic activity, and decreased toxicity.

Authors
Batinić-Haberle, I; Liochev, SI; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Liochev, SI, Spasojević, I, and Fridovich, I. "A potent superoxide dismutase mimic: manganese beta-octabromo-meso-tetrakis-(N-methylpyridinium-4-yl) porphyrin." Arch Biochem Biophys 343.2 (July 15, 1997): 225-233.
PMID
9224734
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
343
Issue
2
Publish Date
1997
Start Page
225
End Page
233
DOI
10.1006/abbi.1997.0157

Solvent effect on second-sphere coordination of ferrioxamine B with substituted 18-crown-6 and 30-crown-10 crown ethers in dichloromethane as compared to chloroform

Stability constants for the second-sphere association of picrate and perchlorate salts of ferrioxamine B (FeHDFB+) with the substituted crown ethers (CE) 18-crown-6, cis-dicyclohexano-18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6 and dibenzo-30-crown-10 were determined in dichloromethane and compared with corresponding data collected in chloroform. The stability of the supramolecular assembly {FeHDFB+ ,CE,X-} is increased in wet CH2Cl2 compared to wet CHCl3 by 0.21 to 0.74 log units. This represents a deviation from the expected trend of higher host-guest stability constants in a less polar solvent. The complexity of the molecular recognition process is discussed in the context of the role of the solvent in relation to the role of the cation and anion, and their hydration shells, and the crown ether structure, in determining the stability of the supramolecular assembly.

Authors
Batinić-Haberle, I; Spasojević, I; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Crumbliss, AL. "Solvent effect on second-sphere coordination of ferrioxamine B with substituted 18-crown-6 and 30-crown-10 crown ethers in dichloromethane as compared to chloroform." Inorganica Chimica Acta 260.1 (1997): 35-41.
Source
scival
Published In
Inorganica Chimica Acta
Volume
260
Issue
1
Publish Date
1997
Start Page
35
End Page
41

Molecular recognition of stable metal complexes through second-sphere coordination by macrocycles

An investigation of second coordination shell complexation of ferrioxamine B by crown ethers, natural ionophores, and other macrocycles through host-guest complexation of the pendant protonated amine group is presented. The influence of guest structure, host structure, solvation shell, and counter ion on host-guest assembly stability is discussed. Application of this form of molecular recognition to bulk liquid membrane transport of a stable metal complex is also presented. The significance of ionophore recognition of a metal complex in the context of iron bioavailability is discussed.

Authors
Crumbliss, AL; Batinić-Haberle, I; Spasojević, I
MLA Citation
Crumbliss, AL, Batinić-Haberle, I, and Spasojević, I. "Molecular recognition of stable metal complexes through second-sphere coordination by macrocycles." Pure and Applied Chemistry 68.6 (1996): 1225-1230.
Source
scival
Published In
Pure and applied chemistry. Chimie pure et appliquee
Volume
68
Issue
6
Publish Date
1996
Start Page
1225
End Page
1230

Stereochemical factors affecting second-sphere co-ordination of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 in chloroform and a comparison with alkali-metal and ammonium cations

Second-sphere co-ordination of ferrioxamine B [Fe(HL)]+ by dicyclohexano-18-crown-6 (eicosahydrodibenzo[b,k][1,4,7,10,13,16]hexaoxacyclooctadecine) occurs through host-guest complex formation with the protonated amine side chain (CH2)5NH3+. The influence of steric factors on the association constants (Ka) for both nitrate and perchlorate salts of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 (CE) in CHCl3 has been investigated. For comparison purposes, association of the perchlorate salt of the indium(III) analogue of ferrioxamine B [In(HL)]+ and the picrate salts of NH4+ and alkali-metal cations are included in this study (picrate = 2,4,6-trinitrophenolate). Although the absolute values of Ka for [M(HL)]X association with CE are strongly dependent on the anion identity, the selectivity ratio expressed for the syn crown ether isomer is 3:1 and is independent of anion variations. Comparison with alkali-metal and ammonium cations shows that the discrimination between syn and anti isomers of cis-dicyclohexano-18-crown-6 is dependent upon cation size and is the least for K+ where the ionic radius best matches the cavity size. While syn isomer discrimination in CHCl3 is closely related to the ionic radius, in water it is related to the hydrated radius. The syn over anti isomer preference exhibited by alkali-metal and ammonium cations is much more pronounced in water than in chloroform, which is likely due to the steric hindrance imposed by the large effective radius of the cations due to their hydration shell. Discrimination between the syn and anti isomers by [M(HL)]+ in CHCl3 is greater than expected based on comparison with the parent NH4+ ion. This is likely due to the significant steric requirements of the bulky metal complex molecule. The selectivity of the syn over the anti isomer is dominated by the preference of the bulky [M(HL)]+ complex for the less hindered face of the syn isomer.

Authors
Batinić-Haberle, I; Spasojević, I; Bartsch, RA; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, Bartsch, RA, and Crumbliss, AL. "Stereochemical factors affecting second-sphere co-ordination of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 in chloroform and a comparison with alkali-metal and ammonium cations." Journal of the Chemical Society, Dalton Transactions 15 (1995): 2503-2508.
Source
scival
Published In
Journal of the Chemical Society. Dalton Transactions
Issue
15
Publish Date
1995
Start Page
2503
End Page
2508
DOI
10.1039/DT9950002503

Supramolecular assembly formation of ferrioxamine B and its Al(III), Ga(III), and In(III) analogues with dicyclohexano-18-crown-6 in chloroform

We have shown that the crown ether dicyclohexano-18-crown-6 recognizes the terminal amine group of deferriferrioxamine B (H4DFB+) and its Al(III), Ga(III), Fe(III), and In(III) complexes (MHDFB+) by host-guest complex formation. Host-guest formation constants for these supramolecular assemblies in chloroform at 25 °C were determined as follows: log Ka(H4DFB+) = 4.56, log Ka(AlHDFB+) = 3.48, log Ka(GaHDFB+) = 3.59, log Ka-(FeHDFB+) = 3.67, log Ka(InHDFB+) = 3.92. Chloroform extraction equilibrium constants (Kex) for the extraction of the MHDFB+ complexes and H4DFB+ in the presence of picrate anion by crown ether were determined as well as distribution constants (Kd) between a chloroform and aqueous phase in the absence of crown ether: log Kex(H4DFB+) = 2.89, log Kex(AlHDFB+) = 2.43, log Kex(GaHDFB+) = 2.84, log Kex(FeHDFB+) = 3.05, log Kex(InHDFB+) = 3.46; log Kd(H4DFB+) = -1.66, log Kd(AlHDFB+) = -1.05, log Kd(GaHDFB+) = -0.75, log Kd(FeHDFB+) = -0.62, log Kd(InHDFB+) = -0.46. In the series InHDFB+, FeHDFB+, GaHDFB+, and AlHDFB+ there is increasing hydration in the second coordination shell, as suggested by a linear relationship between log (Ka,KeX,Kd) and 1/ri (ri = M3+ radius) and M(H2O)63+ hydration enthalpy (ΔHhyd), which consequently increases hydrophilicity (decreases Kd) and increases steric hindrance to crown ether host-guest complex formation (decreases Ka). Correspondingly, the chloroform extraction constants (Kex = Kd·Ka), which depend on chloroform/water distribution (Kd) and host-guest complex formation (Ka), decrease in the same sequence. We conclude that the protonated amine of the free ligand H4DFB+ and its metal complexes provides a recognition site through formation of a supramolecular assembly with a crown ether. Second coordination shell effects (hydrophilicity) provide a mechanism to discriminate between different M(III) complexes of deferriferrioxamine B. The low Kd value obtained for deferriferrioxamine B distribution between the hydrophilic and lipophilic phase is consistent with previous reports concerning the therapeutic use of this ligand to remove intracellular iron from patients with iron overload.

Authors
Spasojević, I; Batinić-Haberle, I; Choo, PL; Crumbliss, AL
MLA Citation
Spasojević, I, Batinić-Haberle, I, Choo, PL, and Crumbliss, AL. "Supramolecular assembly formation of ferrioxamine B and its Al(III), Ga(III), and In(III) analogues with dicyclohexano-18-crown-6 in chloroform." Journal of the American Chemical Society 116.13 (1994): 5714-5721.
Source
scival
Published In
Journal of the American Chemical Society
Volume
116
Issue
13
Publish Date
1994
Start Page
5714
End Page
5721

Hydrolysis of ferrioxamine B in aqueous micellar solution

The association constant for the Fe(III) complex of the linear trihydroxamic acid siderophore ferrioxamine B (FeHDFB+; HDFB2- = H3N-[(CH2)5-N(O)C(O)-(CH2) 2C(O)NH-)]2(CH2)5-N(O)C(O)-CH 3) binding to sodium dodecyl sulfate (SDS) micelles was determined by ultrafiltration and kinetic methods. Both methods are in agreement and yield an average value of the association constant Km = 98 M-1. Association constants for the Al(III) analogue of ferrioxamine B, AlHDFB+, and of the metal-free ligand deferriferrioxamine B, H4DFB+, were also determined by ultrafiltration and found to be Km = 90 and 362 M-1, respectively. Ion-exchange constants (Kex) are calculated from Km values [Kex(FeHDFB+/Na+) = Kex(AlHDFB+/Na+) = 13; Kex(H4DFB+/Na+) = 46] and are discussed in relation to Kex for alkylammonium cations. Kinetic and thermodynamic parameters for the hydrolysis of ferrioxamine B in SDS solutions (0.01-0.15 M) at 25°C have been obtained by stopped-flow and spectrophotometric titration methods at I = 0.1 M (NaClO4/HClO4, NaNO3/HNO3) over a p[H+]tot range from 4.80 to 2.05. Good agreement is found between equilibrium constants determined by spectral and kinetic methods. Comparison with the parameters previously reported for the hydrolysis of FeHDFB+ in aqueous acidic solution suggests that FeHDFB+ resides in the Stern layer of the micelle, and consequently in a region of increased H+ concentration. Once a correction is made for the higher [H+] in the Stern layer, kinetic and thermodynamic parameters obtained in the presence of SDS micelles agree well with those reported for the reaction in aqueous medium. This agreement also gives additional support to the Km and Kex values obtained by ultrafiltration and kinetics. Results reported here show that there is no micellar stabilization of the siderophore complex. © 1994 American Chemical Society.

Authors
Batinić-Haberle, I; Spasojević, I; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Crumbliss, AL. "Hydrolysis of ferrioxamine B in aqueous micellar solution." Inorganic Chemistry 33.14 (1994): 3151-3158.
Source
scival
Published In
Inorganic Chemistry
Volume
33
Issue
14
Publish Date
1994
Start Page
3151
End Page
3158

Functional and chemical characterization of the aging process of an igniter

The igniter consisting of 34% Mg, 60% KNO3, 3% KClO4 and 3% organic binder was subjected to accelerated aging under the conditions of 85% relative humidity at 65 °C, 75 °C and 85 °C, and at 75 °C with 92% relative humidity. Chemical aging was followed through formation of Mg(OH)2 and KNO2. Functional characterization was accomplished in a device constructed to enable simultaneous determination of the heat of combustion and pressure-time recording of the combustion process of both fresh and aged samples. The maximum acceptable deterioration occured at different times depending upon the conditions. The acceleration factor for every 10°C at 85% relative humidity is on average 2.8, leading to a prediction of shelf life of not more than 4 years at 25 °C. At the time when burning characteristics were significantly changed, the mixture suffered only slight chemical changes, with only about 1% Mg(OH)2 and 0.5% KNO2 being formed. Thus, no chemical changes should be tolerated in such formulations.

Authors
Spasojevic, I; Batinic-Haberle, I; Barisin, D
MLA Citation
Spasojevic, I, Batinic-Haberle, I, and Barisin, D. "Functional and chemical characterization of the aging process of an igniter." Propellants, Explosives, Pyrotechnics 18.2 (1993): 89-92.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
18
Issue
2
Publish Date
1993
Start Page
89
End Page
92

Stability characterization of the pyrotechnic system. The degradation of the nitrate oxidant in the presence of magnesium under the accelerated aging conditions

The degradation of the nitrate oxidant was followed in the course of the aging process of tracer pyrotechnic mix containing 22.0% Mg, 46.0% Sr(NO3)2, 22.0% KClO4, 9.0% Al-Mg alloy and 4.0% organic binder. The accelerated aging was conducted under the conditions of the increased humidity (98.5%, 85.0%, 78.5%) at the increased temperature (75°C). Nitrate content as a function of aging time was calculated by substracting nitrite nitrogen from total nitrogen content determined by Devarda's alloy reduction method. The degradation products of the nitrate (nitrite and carbonate) were determined by UV/VIS (Griess reaction) and IR spectroscopy, respectively. Nitrate proved to have a great instability in the presence of the metal, the extent of its conversion to nitrite and carbonate being rather great in comparison to the previously studied alkali metal nitrates in the presence of Mg as well. The loss of the nitrate and the formation of the nitrite and carbonate are governed by the same kinetic laws as fuel degradation to the hydroxide. The rate of the metal oxidation to the hydroxide was faster than the rate of the nitrate degradation process. The failure of the mix is connected to the rather small content of the nitrite (0.4%) while the texture was significantly destroyed.

Authors
Batinic-Haberle, I; Barisin, D; Spasojevic, I; Vranic, Z
MLA Citation
Batinic-Haberle, I, Barisin, D, Spasojevic, I, and Vranic, Z. "Stability characterization of the pyrotechnic system. The degradation of the nitrate oxidant in the presence of magnesium under the accelerated aging conditions." Propellants, Explosives, Pyrotechnics 17.1 (1992): 10-13.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
17
Issue
1
Publish Date
1992
Start Page
10
End Page
13
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