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Wang, Xiao-Fan

Overview:

The current research in the Wang laboratory mainly focuses on the elucidation of molecular nature and signaling mechanisms associated with the initiation of cellular senescence. In addition, we continue to study changes in tumor microenvironment that promotes tumor progression and metastasis, particularly how tumor cells interact with the immune system. Ultimately, we hope that our studies in these areas to lead to the development of novel therapeutics for the treatment of various types of human cancer.

Positions:

Donald and Elizabeth Cooke Professor of Cancer Research, in the School of Medicine

Pharmacology & Cancer Biology
School of Medicine

Professor of Pharmacology and Cancer Biology

Pharmacology & Cancer Biology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

B.S. 1982

B.S. — Wuhan University (China)

Ph.D. 1986

Ph.D. — University of California at Los Angeles

Grants:

Training Program in Developmental and Stem Cell Biology

Administered By
Basic Science Departments
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
May 01, 2001
End Date
April 30, 2022

Analysis of mechanisms associated with Her2-positive breast cancer resistance to therapy

Administered By
Pharmacology & Cancer Biology
AwardedBy
Department of Defense
Role
Principal Investigator
Start Date
September 30, 2016
End Date
September 29, 2019

Fibulin-3 as a Novel Biomarker and Trget in the Breast Tumor Microenvironment

Administered By
Medicine, Medical Oncology
AwardedBy
Susan G. Komen Breast Cancer Foundation
Role
Key Faculty
Start Date
December 01, 2015
End Date
November 30, 2018

The anti-senescence activity of trefoil factor 1

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
April 01, 2012
End Date
March 31, 2018

The Roles of MicroRNAs in Glioblastoma

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 25, 2012
End Date
May 31, 2017

Kinase Target of Diverse Cell Surface Receptors in Cancer Invasion and Metastasis

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Collaborator
Start Date
July 21, 2011
End Date
April 30, 2017

Research Training In Neuro-Oncology

Administered By
Neurosurgery, Neuro-Oncology
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 01, 1998
End Date
August 31, 2016

Molecular determinants underlying herceptin sensitivity and resistance

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 2014
End Date
June 30, 2016

Determine the potential therapeutic effect of HDAC6 inhibitors in inhibiting breast cancer metastasis and glioblastoma

Administered By
Pharmacology & Cancer Biology
AwardedBy
Acetylon Pharmaceuticals, Inc.
Role
Principal Investigator
Start Date
May 02, 2014
End Date
July 20, 2015

The role of TGF-beta in tumorigenesis

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
June 07, 2010
End Date
April 30, 2015

27-hydroxycholesterol as a link between obesity and breast cancer pathogenesis

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Co-Mentor
Start Date
January 01, 2013
End Date
August 31, 2014

Preclinical Evaluation of PK2 Antagonists for Pancreatic Cancer

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 2011
End Date
December 30, 2013

The Role of OTX2 in Molecular Pathogenesis of Medulloblastoma

Administered By
Pathology
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
July 01, 2006
End Date
May 31, 2012

Mechanisms of TGF-B/Smad Signaling

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
May 01, 2008
End Date
February 29, 2012

TGFBI and tumorigenesis

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
September 01, 2006
End Date
July 31, 2011

Rad17- & p53-mediated apoptotic pathways in response to DNA damage

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
August 18, 2006
End Date
July 31, 2011

Research Training In Neuro-Oncology

Administered By
Neurosurgery, Neuro-Oncology
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
September 15, 2005
End Date
August 31, 2010

TGFbeta-PTEN Interactions in Glioma Biology & Therapy

Administered By
Neurology, General & Community Neurology
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
August 01, 2006
End Date
September 30, 2008

Molecular Mechanisms of SPARC Mediated Glioma Invasion

Administered By
Neurology, General & Community Neurology
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
February 15, 2006
End Date
September 30, 2008

TGF-Beta Signaling in MSCs and Osteoblast

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
January 01, 2004
End Date
April 30, 2008

Analysis of Rad17-mediated Checkpoint Signaling

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 18, 2002
End Date
April 30, 2008

Analysis of the Functional Role of TPF in Tumorigenesis

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 2000
End Date
June 30, 2005

The Role Of Tumor Supressor Smads In Tgf-B Signaling

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 1998
End Date
April 30, 2004

Functional Analysis of TGFRP, A Putative Angiogenic Factor in Breast Carcinogenics

Administered By
Pharmacology & Cancer Biology
AwardedBy
US Army Medical Research
Role
Principal Investigator
Start Date
July 01, 1999
End Date
June 30, 2002

The Role Of Tgfb In Brain Tumors

Administered By
Neurology, General & Community Neurology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
July 01, 1998
End Date
June 30, 2001

Tgf-Beta Signaling Pathway And Cell Growth Regulation

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
January 01, 1995
End Date
June 30, 2001

Tgf-B Signaling Pathway And Cell Growth Regulation

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 26, 1996
End Date
June 30, 1999

Examination Of Tgfb Induced Cell Death Pathway

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
August 01, 1995
End Date
July 31, 1998

Analysis Of Tgf-B Receptor Ii Signalling Mechanism

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
January 01, 1994
End Date
December 31, 1995

Analysis Of Tgf Beta Receptor Ii Signalling Mechanism

Administered By
Pharmacology & Cancer Biology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
January 01, 1993
End Date
December 31, 1995
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Awards:

International Scientific Cooperation Award. Chinese Academy of Sciences.

Type
International
Awarded By
Chinese Academy of Sciences
Date
January 01, 2013

Ray Wu Award. Chinese Biological Investigators Society, USA.

Type
International
Awarded By
Chinese Biological Investigators Society, USA
Date
January 01, 2013

Outstanding Alumni Award. Wuhan University, China.

Type
International
Awarded By
Wuhan University (China)
Date
January 01, 2011

AAAS Fellows. American Association for the Advancement of Science, The.

Type
National
Awarded By
American Association for the Advancement of Science, The
Date
January 01, 2009

Publications:

TGF-β Family Signaling in the Control of Cell Proliferation and Survival.

The transforming growth factor β (TGF-β) family controls many fundamental aspects of cellular behavior. With advances in the molecular details of the TGF-β signaling cascade and its cross talk with other signaling pathways, we now have a more coherent understanding of the cytostatic program induced by TGF-β. However, the molecular mechanisms are still largely elusive for other cellular processes that are regulated by TGF-β and determine a cell's proliferation and survival, apoptosis, dormancy, autophagy, and senescence. The difficulty in defining TGF-β's roles partly stems from the context-dependent nature of TGF-β signaling. Here, we review our current understanding and recent progress on the biological effects of TGF-β at the cellular level, with the hope of providing a framework for understanding how cells respond to TGF-β signals in specific contexts, and why disruption of such mechanisms may result in different human diseases including cancer.

Authors
Zhang, Y; Alexander, PB; Wang, X-F
MLA Citation
Zhang, Y, Alexander, PB, and Wang, X-F. "TGF-β Family Signaling in the Control of Cell Proliferation and Survival." Cold Spring Harbor perspectives in biology 9.4 (April 2017). (Review)
PMID
27920038
Source
epmc
Published In
Cold Spring Harbor perspectives in biology
Volume
9
Issue
4
Publish Date
2017
DOI
10.1101/cshperspect.a022145

Distinct Receptor Tyrosine Kinase Subsets Mediate Anti-HER2 Drug Resistance in Breast Cancer.

Targeted inhibitors of the human epidermal growth factor receptor 2 (HER2), such as trastuzumab and lapatinib, are among the first examples of molecularly targeted cancer therapy and have proven largely effective for the treatment of HER2-positive breast cancers. However, approximately half of those patients either do not respond to these therapies or develop secondary resistance. Although a few signaling pathways have been implicated, a comprehensive understanding of mechanisms underlying HER2 inhibitor drug resistance is still lacking. To address this critical question, we undertook a concerted approach using patient expression data sets, HER2-positive cell lines, and tumor samples biopsied both before and after trastuzumab treatment. Together, these methods revealed that high expression and activation of a specific subset of receptor tyrosine kinases (RTKs) was strongly associated with poor clinical prognosis and the development of resistance. Mechanistically, these RTKs are capable of maintaining downstream signal transduction to promote tumor growth via the suppression of cellular senescence. Consequently, these findings provide the rationale for the design of therapeutic strategies for overcoming drug resistance in breast cancer via combinational inhibition of the limited number of targets from this specific subset of RTKs.

Authors
Alexander, PB; Chen, R; Gong, C; Yuan, L; Jasper, JS; Ding, Y; Markowitz, GJ; Yang, P; Xu, X; McDonnell, DP; Song, E; Wang, X-F
MLA Citation
Alexander, PB, Chen, R, Gong, C, Yuan, L, Jasper, JS, Ding, Y, Markowitz, GJ, Yang, P, Xu, X, McDonnell, DP, Song, E, and Wang, X-F. "Distinct Receptor Tyrosine Kinase Subsets Mediate Anti-HER2 Drug Resistance in Breast Cancer." The Journal of biological chemistry 292.2 (January 2017): 748-759.
Website
http://hdl.handle.net/10161/15359
PMID
27903634
Source
epmc
Published In
The Journal of biological chemistry
Volume
292
Issue
2
Publish Date
2017
Start Page
748
End Page
759
DOI
10.1074/jbc.m116.754960

UHRF1 is required for basal stem cell proliferation in response to airway injury.

Cellular senescence is a cell fate characterized by an irreversible cell cycle arrest, but the molecular mechanism underlying this senescence hallmark remains poorly understood. Through an unbiased search for novel senescence regulators in airway basal cells, we discovered that the epigenetic regulator ubiquitin-like with PHD and ring finger domain-containing protein 1 (UHRF1) is critical for regulating cell cycle progression. Upon injury, basal cells in the mouse airway rapidly induce the expression of UHRF1 in order to stimulate stem cell proliferation and tissue repair. Targeted depletion of Uhrf1 specifically in airway basal cells causes a profound defect in cell cycle progression. Consistently, cultured primary human basal cells lacking UHRF1 do not exhibit cell death or differentiation phenotypes but undergo a spontaneous program of senescence. Mechanistically, UHRF1 loss induces G1 cell cycle arrest by abrogating DNA replication factory formation as evidenced by loss of proliferating cell nuclear antigen (PCNA) puncta and an inability to enter the first cell cycle. This proliferation defect is partially mediated by the p15 pathway. Overall, our study provides the first evidence of an indispensable role of UHRF1 in somatic stem cells proliferation during the process of airway regeneration.

Authors
Xiang, H; Yuan, L; Gao, X; Alexander, PB; Lopez, O; Lau, C; Ding, Y; Chong, M; Sun, T; Chen, R; Liu, S-Q; Wu, H; Wan, Y; Randell, SH; Li, Q-J; Wang, X-F
MLA Citation
Xiang, H, Yuan, L, Gao, X, Alexander, PB, Lopez, O, Lau, C, Ding, Y, Chong, M, Sun, T, Chen, R, Liu, S-Q, Wu, H, Wan, Y, Randell, SH, Li, Q-J, and Wang, X-F. "UHRF1 is required for basal stem cell proliferation in response to airway injury." Cell discovery 3 (January 2017): 17019-.
Website
http://hdl.handle.net/10161/15358
PMID
28626588
Source
epmc
Published In
Cell Discovery
Volume
3
Publish Date
2017
Start Page
17019
DOI
10.1038/celldisc.2017.19

The histone deacetylase inhibitor trichostatin a decreases lymphangiogenesis by inducing apoptosis and cell cycle arrest via p21-dependent pathways

Authors
Hrgovic, I; Doll, M; Kleemann, J; Wang, X-F; Zoeller, N; Pinter, A; Kippenberger, S; Kaufmann, R; Meissner, M
MLA Citation
Hrgovic, I, Doll, M, Kleemann, J, Wang, X-F, Zoeller, N, Pinter, A, Kippenberger, S, Kaufmann, R, and Meissner, M. "The histone deacetylase inhibitor trichostatin a decreases lymphangiogenesis by inducing apoptosis and cell cycle arrest via p21-dependent pathways." December 2016.
Source
crossref
Published In
BMC Cancer
Volume
16
Issue
1
Publish Date
2016
DOI
10.1186/s12885-016-2807-y

Carcinogen 7,12-dimethylbenz[a]anthracene-induced mammary tumorigenesis is accelerated in Smad3 heterozygous mice compared to Smad3 wild type mice.

Previous studies based on cell culture and xenograft animal models suggest that Smad3 has tumor suppressor function for breast cancer during early stages of tumorigenesis. In this report, we show that DMBA (7,12-dimethylbenz[a]anthracene), a chemical carcinogen, induces mammary tumor formation at a significantly higher frequency in the Smad3 heterozygous mice than in the Smad3 wild type mice. This is the first genetic evidence showing that Smad3 inhibits mammary tumor formation in a mouse model. Our findings support the notion that Smad3 has important tumor suppressor function for breast cancer.

Authors
Liu, Z; Kundu-Roy, T; Matsuura, I; Wang, G; Lin, Y; Lou, Y-R; Barnard, NJ; Wang, X-F; Huang, M-T; Suh, N; Liu, F
MLA Citation
Liu, Z, Kundu-Roy, T, Matsuura, I, Wang, G, Lin, Y, Lou, Y-R, Barnard, NJ, Wang, X-F, Huang, M-T, Suh, N, and Liu, F. "Carcinogen 7,12-dimethylbenz[a]anthracene-induced mammary tumorigenesis is accelerated in Smad3 heterozygous mice compared to Smad3 wild type mice." Oncotarget 7.40 (October 2016): 64878-64885.
PMID
27588495
Source
epmc
Published In
Oncotarget
Volume
7
Issue
40
Publish Date
2016
Start Page
64878
End Page
64885
DOI
10.18632/oncotarget.11713

The histone deacetylase inhibitor trichostatin a decreases lymphangiogenesis by inducing apoptosis and cell cycle arrest via p21-dependent pathways.

The formation of new lymphatic vessels provides an additional route for tumour cells to metastasize. Therefore, inhibiting lymphangiogenesis represents an interesting target in cancer therapy. First evidence suggests that histone deacetylase inhibitors (HDACi) may mediate part of their antitumor effects by interfering with lymphangiogenesis. However, the underlying mechanisms of HDACi induced anti-lymphangiogenic properties are not fully investigated so far and in part remain unknown.Human lymphatic endothelial cells (LEC) were cultured in vitro and treated with or without HDACi. Effects of HDACi on proliferation and cell cycle progress were analysed by BrdU assay and flow cytometry. Apoptosis was measured by quantifying mono- and oligonucleosomes in the cytoplasmic fraction of cell lysates. In vitro lymphangiogenesis was investigated using the Matrigel short term lymphangiogenesis assay. The effects of TSA on cell cycle regulatory proteins and apoptosis-related proteins were examined by western blotting, immunofluorescence staining and semi-quantitative RT-PCR. Protein- and mRNA half-life of p21 were analysed by western blotting and quantitative RT-PCR. The activity of the p21 promoter was determined using a dual luciferase assay and DNA-binding activity of Sp1/3 was investigated using EMSA. Furthermore, siRNA assays were performed to analyse the role of p21 and p53 on TSA-mediated anti-lymphangiogenic effects.We found that HDACi inhibited cell proliferation and that the pan-HDACi TSA induced G0/G1 arrest in LEC. Cell cycle arrest was accompanied by up-regulation of p21, p27 and p53. Additionally, we observed that p21 protein accumulated in cellular nuclei after treatment with TSA. Moreover, we found that p21 mRNA was significantly up-regulated by TSA, while the protein and mRNA half-life remained largely unaffected. The promoter activity of p21 was enhanced by TSA indicating a transcriptional mechanism. Subsequent EMSA analyses showed increased constitutive Sp1/3-dependent DNA binding in response to HDACi. We demonstrated that p53 was not required for TSA induced p21 expression and growth inhibition of LECs. Interestingly, siRNA-mediated p21 depletion almost completely reversed the anti-proliferative effects of TSA in LEC. In addition, TSA induced apoptosis by cytochrome c release contributed to activating caspases-9, -7 and -3 and downregulating the anti-apoptotic proteins cIAP-1 and -2.In conclusion, we demonstrate that TSA - a pan-HDACi - has distinct anti-lymphangiogenic effects in primary human lymphatic endothelial cells by activating intrinsic apoptotic pathway and cell cycle arrest via p21-dependent pathways.

Authors
Hrgovic, I; Doll, M; Kleemann, J; Wang, X-F; Zoeller, N; Pinter, A; Kippenberger, S; Kaufmann, R; Meissner, M
MLA Citation
Hrgovic, I, Doll, M, Kleemann, J, Wang, X-F, Zoeller, N, Pinter, A, Kippenberger, S, Kaufmann, R, and Meissner, M. "The histone deacetylase inhibitor trichostatin a decreases lymphangiogenesis by inducing apoptosis and cell cycle arrest via p21-dependent pathways." BMC cancer 16.1 (September 30, 2016): 763-.
PMID
27716272
Source
epmc
Published In
BMC Cancer
Volume
16
Issue
1
Publish Date
2016
Start Page
763
DOI
10.1186/s12885-016-2807-y

HIF-miR-215-KDM1B promotes glioma-initiating cell adaptation to hypoxia.

Authors
Hu, J; Wang, X-F
MLA Citation
Hu, J, and Wang, X-F. "HIF-miR-215-KDM1B promotes glioma-initiating cell adaptation to hypoxia." Cell cycle (Georgetown, Tex.) 15.15 (August 2016): 1939-1940.
PMID
27164290
Source
epmc
Published In
Cell Cycle
Volume
15
Issue
15
Publish Date
2016
Start Page
1939
End Page
1940
DOI
10.1080/15384101.2016.1181877

Iron overload in hereditary tyrosinemia type 1 induces liver injury through the Sp1/Tfr2/hepcidin axis.

Iron is an essential metal for fundamental metabolic processes, but little is known regarding the involvement of iron in other nutritional disorders. In the present study, we investigated disordered iron metabolism in a murine model of hereditary tyrosinemia type I (HT1), a disease of the tyrosine degradation pathway.We analysed the status of iron accumulation following NTBC withdrawal from Fah(-/-) mice, a murine model for HT1. Liver histology and serum parameters were used to assess the extent of liver injury and iron deposition. To determine the physiological significance of iron accumulation, mice were subjected to a low-iron food intake to reduce the iron accumulation. Mechanistic studies were performed on tissues and cells using immunoblotting, qRT-PCR, adenovirus transfection and other assays.Severe iron overload was observed in the murine model of HT1 with dramatically elevated hepatic and serum iron levels. Mechanistic studies revealed that downregulation and dysfunction of Tfr2 decreased hepcidin, leading to iron overload. The Fah(-/-) hepatocytes lost the ability of transferrin-sensitive induction of hepcidin. Forced expression of Tfr2 in the murine liver reduced the iron accumulation. Moreover, transcription factor Sp1 was downregulated and identified as a new regulator of Tfr2 here. Additionally, low-iron food intake effectively reduced the iron deposits, protected the liver and prolonged the survival in these mice.Iron was severely overloaded in the HT1 mice via the Sp1/Tfr2/Hepcidin axis. The iron overload induced liver injury in the HT1 mice, and reduction of the iron accumulation ameliorated liver injury.Primary and secondary iron overload is an abnormal status affecting millions of people worldwide. Here, we reported severe iron overload in a murine model of HT1, a disease of the tyrosine degradation pathway, and elucidated the mechanistic basis and the physiological significance of iron overload in HT1. These studies are of general interest not only with respect to secondary iron-induced liver injury in HT1 but also are important to elucidate the crosstalk between the two metabolic pathways.

Authors
Bao, W-D; Fan, Y; Deng, Y-Z; Long, L-Y; Wang, J-J; Guan, D-X; Qian, Z-Y; An, P; Feng, Y-Y; He, Z-Y; Wang, X-F; Phillip Koeffler, H; Hu, R; Wang, J; Wang, X; Wang, F; Li, J-J; Xie, D
MLA Citation
Bao, W-D, Fan, Y, Deng, Y-Z, Long, L-Y, Wang, J-J, Guan, D-X, Qian, Z-Y, An, P, Feng, Y-Y, He, Z-Y, Wang, X-F, Phillip Koeffler, H, Hu, R, Wang, J, Wang, X, Wang, F, Li, J-J, and Xie, D. "Iron overload in hereditary tyrosinemia type 1 induces liver injury through the Sp1/Tfr2/hepcidin axis." Journal of hepatology 65.1 (July 2016): 137-145.
PMID
27013087
Source
epmc
Published In
Journal of Hepatology
Volume
65
Issue
1
Publish Date
2016
Start Page
137
End Page
145
DOI
10.1016/j.jhep.2016.03.007

Inflammation-Dependent IL18 Signaling Restricts Hepatocellular Carcinoma Growth by Enhancing the Accumulation and Activity of Tumor-Infiltrating Lymphocytes.

Chronic inflammation in liver tissue is an underlying cause of hepatocellular carcinoma. High levels of inflammatory cytokine IL18 in the circulation of patients with hepatocellular carcinoma correlates with poor prognosis. However, conflicting results have been reported for IL18 in hepatocellular carcinoma development and progression. In this study, we used tissue specimens from hepatocellular carcinoma patients and clinically relevant mouse models of hepatocellular carcinoma to evaluate IL18 expression and function. In a mouse model of liver fibrosis that recapitulates a tumor-promoting microenvironment, global deletion of the IL18 receptor IL18R1 enhanced tumor growth and burden. Similarly, in a carcinogen-induced model of liver tumorigenesis, IL18R1 deletion increased tumor burden. Mechanistically, we found that IL18 exerted inflammation-dependent tumor-suppressive effects largely by promoting the differentiation, activity, and survival of tumor-infiltrating T cells. Finally, differences in the expression of IL18 in tumor tissue versus nontumor tissue were more predictive of patient outcome than overall tissue expression. Taken together, our findings resolve a long-standing contradiction regarding a tumor-suppressive role for IL18 in established hepatocellular carcinoma and provide a mechanistic explanation for the complex relationship between its expression pattern and hepatocellular carcinoma prognosis. Cancer Res; 76(8); 2394-405. ©2016 AACR.

Authors
Markowitz, GJ; Yang, P; Fu, J; Michelotti, GA; Chen, R; Sui, J; Yang, B; Qin, W-H; Zhang, Z; Wang, F-S; Diehl, AM; Li, Q-J; Wang, H; Wang, X-F
MLA Citation
Markowitz, GJ, Yang, P, Fu, J, Michelotti, GA, Chen, R, Sui, J, Yang, B, Qin, W-H, Zhang, Z, Wang, F-S, Diehl, AM, Li, Q-J, Wang, H, and Wang, X-F. "Inflammation-Dependent IL18 Signaling Restricts Hepatocellular Carcinoma Growth by Enhancing the Accumulation and Activity of Tumor-Infiltrating Lymphocytes." Cancer research 76.8 (April 2016): 2394-2405.
PMID
26893476
Source
epmc
Published In
Cancer Research
Volume
76
Issue
8
Publish Date
2016
Start Page
2394
End Page
2405
DOI
10.1158/0008-5472.can-15-1548

MiR-148a functions to suppress metastasis and serves as a prognostic indicator in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) presents a major challenge in the clinic due to its lack of reliable prognostic markers and targeted therapies. Accumulating evidence strongly supports the notion that microRNAs (miRNAs) are involved in tumorigenesis and could serve as biomarkers for diagnostic purposes. To identify miRNAs that functionally suppress metastasis of TNBC, we employed a concerted approach with selecting miRNAs that display differential expression profiles from bioinformatic analyses of breast cancer patient databases and validating top candidates with functional assays using breast cancer cell lines and mouse models. We have found that miR-148a exhibits properties as a tumor suppressor as its expression is inversely correlated with the ability of both human and mouse breast cancer cells to colonize the lung in mouse xenograft tumor models. Mechanistically, miR-148a appears to suppress the extravasation process of cancer cells, likely by targeting two genes WNT1 and NRP1 in a cell non-autonomous manner. Importantly, lower expression of miR-148a is detected in higher-grade tumor samples and correlated with increased likelihood to develop metastases and poor prognosis in subsets of breast cancer patients, particularly those with TNBC. Thus, miR-148a is functionally defined as a suppressor of breast cancer metastasis and may serve as a prognostic biomarker for this disease.

Authors
Xu, X; Zhang, Y; Jasper, J; Lykken, E; Alexander, PB; Markowitz, GJ; McDonnell, DP; Li, Q-J; Wang, X-F
MLA Citation
Xu, X, Zhang, Y, Jasper, J, Lykken, E, Alexander, PB, Markowitz, GJ, McDonnell, DP, Li, Q-J, and Wang, X-F. "MiR-148a functions to suppress metastasis and serves as a prognostic indicator in triple-negative breast cancer." Oncotarget 7.15 (April 2016): 20381-20394.
PMID
26967387
Source
epmc
Published In
Oncotarget
Volume
7
Issue
15
Publish Date
2016
Start Page
20381
End Page
20394
DOI
10.18632/oncotarget.7953

Dimethylfumarate effectively inhibits lymphangiogenesis via p21 induction and G1 cell cycle arrest.

Different pathologies, such as lymphoedema, cancer or psoriasis, are associated with abnormal lymphatic vessel formation. Therefore, influencing lymphangiogenesis is an interesting target. Recent evidence suggests that dimethylfumarate (DMF), an antipsoriatic agent, might have antitumorigenic and antilymphangiogenic properties. To prove this assumption, we performed proliferation and functional assays with primary human dermal lymphendothelial cells (DLEC). We could demonstrated that DMF suppresses DLEC proliferation and formation of capillary-like structures. Underlying apoptotic mechanisms could be ruled out. Cell cycle analysis demonstrated a pronounced G1-arrest. Further evaluations revealed increases in p21 expression. In addition, DMF suppressed Cyclin D1 and Cyclin A expression in a concentration-dependent manner. p21 knockdown experiments demonstrated a p21-dependent mechanism of regulation. Further analysis showed an increased p21 mRNA expression after DMF treatment. This transcriptional regulation was enforced by post-transcriptional and post-translational mechanisms. In addition, we could demonstrate that the combination of a proteasomal inhibitor and DMF superinduced the p21 expression. Hence, DMF is a new antilymphangiogenic compound and might be used in various illnesses associated with increased lymphangiogenesis.

Authors
Valesky, EM; Hrgovic, I; Doll, M; Wang, X-F; Pinter, A; Kleemann, J; Kaufmann, R; Kippenberger, S; Meissner, M
MLA Citation
Valesky, EM, Hrgovic, I, Doll, M, Wang, X-F, Pinter, A, Kleemann, J, Kaufmann, R, Kippenberger, S, and Meissner, M. "Dimethylfumarate effectively inhibits lymphangiogenesis via p21 induction and G1 cell cycle arrest." Experimental dermatology 25.3 (March 2016): 200-205.
PMID
26663097
Source
epmc
Published In
Experimental Dermatology
Volume
25
Issue
3
Publish Date
2016
Start Page
200
End Page
205
DOI
10.1111/exd.12907

TGF-β-Regulated MicroRNAs and Their Function in Cancer Biology.

The transforming growth factor-β (TGF-β) is known to regulate a large number of biological processes and is involved in various aspects of tumor development. Recent studies have shown that the biogenesis of miRNAs can be regulated by TGF-β signaling directly via Smad-dependent mechanisms and/or other unknown mechanisms, which may induce autoregulatory feedback loops in response to the activation of TGF-β signaling, influencing the fate of tumor cells. In this chapter, we summarize the currently described mechanisms underlying TGF-β's regulation of miRNA biogenesis, and the functional role of TGF-β-regulated miRNAs in tumor initiation, epithelial-mesenchymal transition, and tumor microenvironment modulation. Finally, we introduce methods to study TGF-β-regulated miRNAs and their functions in tumor progression and metastasis using an example of publication from our lab demonstrating the presence of a TGF-β-miR-34a-CCL22 signaling axis, which serves as a potent etiological pathway for the development of hepatocellular carcinoma venous metastases.

Authors
Yang, P; Zhang, Y; Markowitz, GJ; Guo, X; Wang, X-F
MLA Citation
Yang, P, Zhang, Y, Markowitz, GJ, Guo, X, and Wang, X-F. "TGF-β-Regulated MicroRNAs and Their Function in Cancer Biology." Methods in molecular biology (Clifton, N.J.) 1344 (January 2016): 325-339.
PMID
26520135
Source
epmc
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
1344
Publish Date
2016
Start Page
325
End Page
339
DOI
10.1007/978-1-4939-2966-5_21

MiR-215 Is Induced Post-transcriptionally via HIF-Drosha Complex and Mediates Glioma-Initiating Cell Adaptation to Hypoxia by Targeting KDM1B.

The hypoxic tumor microenvironment serves as a niche for maintaining the glioma-initiating cells (GICs) that are critical for glioblastoma (GBM) occurrence and recurrence. Here, we report that hypoxia-induced miR-215 is vital for reprograming GICs to fit the hypoxic microenvironment via suppressing the expression of an epigenetic regulator KDM1B and modulating activities of multiple pathways. Interestingly, biogenesis of miR-215 and several miRNAs is accelerated post-transcriptionally by hypoxia-inducible factors (HIFs) through HIF-Drosha interaction. Moreover, miR-215 expression correlates inversely with KDM1B while correlating positively with HIF1α and GBM progression in patients. These findings reveal a direct role of HIF in regulating miRNA biogenesis and consequently activating the miR-215-KDM1B-mediated signaling required for GIC adaptation to hypoxia.

Authors
Hu, J; Sun, T; Wang, H; Chen, Z; Wang, S; Yuan, L; Liu, T; Li, H-R; Wang, P; Feng, Y; Wang, Q; McLendon, RE; Friedman, AH; Keir, ST; Bigner, DD; Rathmell, J; Fu, X-D; Li, Q-J; Wang, H; Wang, X-F
MLA Citation
Hu, J, Sun, T, Wang, H, Chen, Z, Wang, S, Yuan, L, Liu, T, Li, H-R, Wang, P, Feng, Y, Wang, Q, McLendon, RE, Friedman, AH, Keir, ST, Bigner, DD, Rathmell, J, Fu, X-D, Li, Q-J, Wang, H, and Wang, X-F. "MiR-215 Is Induced Post-transcriptionally via HIF-Drosha Complex and Mediates Glioma-Initiating Cell Adaptation to Hypoxia by Targeting KDM1B." Cancer cell 29.1 (January 2016): 49-60.
Website
http://hdl.handle.net/10161/11667
PMID
26766590
Source
epmc
Published In
Cancer Cell
Volume
29
Issue
1
Publish Date
2016
Start Page
49
End Page
60
DOI
10.1016/j.ccell.2015.12.005

Noncoding RNAs Regulating Cancer Signaling Network.

The cellular signaling network plays a fundamental role during development and disease, especially cancer progression. By deregulating signaling pathways, cancer cells acquire hallmarks of the disease including uncontrolled proliferation, evasion from cell death, activation of angiogenesis, invasion, and metastasis. Noncoding RNAs make substantial contributions to regulating signal transduction in cancer, thereby promoting or suppressing different biological processes during tumorigenesis. This chapter provides an overview on the regulatory functions of noncoding RNAs in the signaling network in cancer cells. It summarizes examples of noncoding RNAs that act as oncogenes or tumor-suppressing genes involved in key signal pathways as well as signal crosstalk in cancer cells.

Authors
Hu, J; Markowitz, GJ; Wang, X
MLA Citation
Hu, J, Markowitz, GJ, and Wang, X. "Noncoding RNAs Regulating Cancer Signaling Network." Advances in experimental medicine and biology 927 (January 2016): 297-315. (Review)
PMID
27376740
Source
epmc
Published In
Advances in experimental medicine and biology
Volume
927
Publish Date
2016
Start Page
297
End Page
315
DOI
10.1007/978-981-10-1498-7_11

Isolation of Glioma-Initiating Cells for Biological Study.

Glioblastoma multiforme (GBM, WHO grade IV astrocytoma) is the most common and lethal primary brain tumor in adults, with an average survival of slightly more than 1 year after initial diagnosis. GBMs display significant heterogeneity within the tumor mass, among which a subpopulation of cells called glioma-initiating cells (GICs) is responsible for tumorigenesis and resistance to conventional therapies. Therefore, understanding the mechanism underlying the biological properties of GICs would help develop better therapies to target this population for GBM treatment. This protocol provides detailed procedures to isolate GICs and non-GICs from patient's specimen and glioma xenografts, which serves as the first step for the biological studies of GICs. Upon separation of GICs and non-GICs, a series of studies, such as expression profiling and functional screen, etc., can be performed to identify signal pathways responsible for the malignant nature of GICs. Besides, translational studies can also be conducted to examine drug responses of GICs. In sum, isolation of GICs with reliable methods will provide the basis for the further biological studies.

Authors
Hu, J; Markowitz, G; Wang, X-F
MLA Citation
Hu, J, Markowitz, G, and Wang, X-F. "Isolation of Glioma-Initiating Cells for Biological Study." Advances in experimental medicine and biology 899 (January 2016): 197-209.
PMID
27325268
Source
epmc
Published In
Advances in experimental medicine and biology
Volume
899
Publish Date
2016
Start Page
197
End Page
209
DOI
10.1007/978-3-319-26666-4_11

Smad3 Signaling Promotes Fibrosis While Preserving Cardiac and Aortic Geometry in Obese Diabetic Mice.

Heart failure in diabetics is associated with cardiac hypertrophy, fibrosis and diastolic dysfunction. Activation of transforming growth factor-β/Smad3 signaling in the diabetic myocardium may mediate fibrosis and diastolic heart failure, while preserving matrix homeostasis. We hypothesized that Smad3 may play a key role in the pathogenesis of cardiovascular remodeling associated with diabetes mellitus and obesity.We generated leptin-resistant db/db Smad3 null mice and db/db Smad3+/- animals. Smad3 haploinsufficiency did not affect metabolic function in db/db mice, but protected from myocardial diastolic dysfunction, while causing left ventricular chamber dilation. Improved cardiac compliance and chamber dilation in db/db Smad3+/- animals were associated with decreased cardiomyocyte hypertrophy, reduced collagen deposition, and accentuated matrix metalloproteinase activity. Attenuation of hypertrophy and fibrosis in db/db Smad3+/- hearts was associated with reduced myocardial oxidative and nitrosative stress. db/db Smad3 null mice had reduced weight gain and decreased adiposity associated with attenuated insulin resistance, but also exhibited high early mortality, in part, because of spontaneous rupture of the ascending aorta. Ultrasound studies showed that both lean and obese Smad3 null animals had significant aortic dilation. Aortic dilation in db/db Smad3 null mice occurred despite reduced hypertension and was associated with perturbed matrix balance in the vascular wall.Smad3 mediates diabetic cardiac hypertrophy, fibrosis, and diastolic dysfunction, while preserving normal cardiac geometry and maintaining the integrity of the vascular wall.

Authors
Biernacka, A; Cavalera, M; Wang, J; Russo, I; Shinde, A; Kong, P; Gonzalez-Quesada, C; Rai, V; Dobaczewski, M; Lee, D-W; Wang, X-F; Frangogiannis, NG
MLA Citation
Biernacka, A, Cavalera, M, Wang, J, Russo, I, Shinde, A, Kong, P, Gonzalez-Quesada, C, Rai, V, Dobaczewski, M, Lee, D-W, Wang, X-F, and Frangogiannis, NG. "Smad3 Signaling Promotes Fibrosis While Preserving Cardiac and Aortic Geometry in Obese Diabetic Mice." Circulation. Heart failure 8.4 (July 2015): 788-798.
PMID
25985794
Source
epmc
Published In
Circulation: Heart Failure
Volume
8
Issue
4
Publish Date
2015
Start Page
788
End Page
798
DOI
10.1161/circheartfailure.114.001963

A niche role for cancer exosomes in metastasis.

Cancer cells are known to secrete exosomes with pro-metastatic effects. Pancreatic-cancer-derived exosomes are now shown to promote liver metastasis by eliciting pre-metastatic niche formation through a multi-step process. This involves uptake of exosome-derived factors by liver Kupffer cells and hepatic stellate cell activation to generate a fibrotic microenvironment with immune cell infiltrates that favours metastasis.

Authors
Zhang, Y; Wang, X-F
MLA Citation
Zhang, Y, and Wang, X-F. "A niche role for cancer exosomes in metastasis." Nature cell biology 17.6 (June 2015): 709-711.
PMID
26022917
Source
epmc
Published In
Nature Cell Biology
Volume
17
Issue
6
Publish Date
2015
Start Page
709
End Page
711
DOI
10.1038/ncb3181

Resistance to receptor tyrosine kinase inhibition in cancer: molecular mechanisms and therapeutic strategies.

Drug resistance is a major factor that limits the efficacy of targeted cancer therapies. In this review, we discuss the main known mechanisms of resistance to receptor tyrosine kinase inhibitors, which are the most prevalent class of targeted therapeutic agent in current clinical use. Here we focus on bypass track resistance, which involves the activation of alternate signaling molecules by tumor cells to bypass inhibition and maintain signaling output, and consider the problems of signaling pathway redundancy and how the activation of different receptor tyrosine kinases translates into intracellular signal transduction in different cancer types. This information is presented in the context of research strategies for the discovery of new targets for pharmacological intervention, with the goal of overcoming resistance in order to improve patient outcomes.

Authors
Alexander, PB; Wang, X-F
MLA Citation
Alexander, PB, and Wang, X-F. "Resistance to receptor tyrosine kinase inhibition in cancer: molecular mechanisms and therapeutic strategies." Frontiers of medicine 9.2 (June 2015): 134-138. (Review)
PMID
25957263
Source
epmc
Published In
Frontiers of Medicine
Volume
9
Issue
2
Publish Date
2015
Start Page
134
End Page
138
DOI
10.1007/s11684-015-0396-9

SMAD3 deficiency promotes vessel wall remodeling, collagen fiber reorganization and leukocyte infiltration in an inflammatory abdominal aortic aneurysm mouse model.

TGF-β signaling plays critical roles in the pathogenesis of aneurysms; however, it is still unclear whether its role is protective or destructive. In this study, we investigate the role of SMAD3 in the pathogenesis of calcium chloride (CaCl2)-induced abdominal aortic aneurysms (AAA) in Smad3(-/-), Smad3(+/-) and Smad3(+/+) mice. We find that loss of SMAD3 drastically increases wall thickening of the abdominal aorta. Histological analyses show significant vessel wall remodeling with elastic fiber fragmentation. Remarkably, under polarized light, collagen fibers in the hyperplastic adventitia of Smad3(-/-) mice show extensive reorganization accompanied by loosely packed thin and radial collagen fibers. The expressions of matrix metalloproteinases including MMP2, MMP9, and MMP12 and infiltration of macrophage/T cells are drastically enhanced in the vascular wall of Smad3(-/-) mice. We also observe marked increase of NF-κB and ERK1/2 signaling as well as the expression of nuclear Smad2, Smad4 and TGF-β1 in the vessel wall of Smad3(-/-) mice. In addition, we find that SMAD3 expression is reduced in the dedifferentiated medial smooth muscle-like cells of human AAA patients. These findings provide direct in vivo evidence to support the essential roles of SMAD3 in protecting vessel wall integrity and suppressing inflammation in the pathogenesis of AAAs.

Authors
Dai, X; Shen, J; Annam, NP; Jiang, H; Levi, E; Schworer, CM; Tromp, G; Arora, A; Higgins, M; Wang, X-F; Yang, M; Li, HJ; Zhang, K; Kuivaniemi, H; Li, L
MLA Citation
Dai, X, Shen, J, Annam, NP, Jiang, H, Levi, E, Schworer, CM, Tromp, G, Arora, A, Higgins, M, Wang, X-F, Yang, M, Li, HJ, Zhang, K, Kuivaniemi, H, and Li, L. "SMAD3 deficiency promotes vessel wall remodeling, collagen fiber reorganization and leukocyte infiltration in an inflammatory abdominal aortic aneurysm mouse model." Scientific reports 5 (May 18, 2015): 10180-.
PMID
25985281
Source
epmc
Published In
Scientific Reports
Volume
5
Publish Date
2015
Start Page
10180
DOI
10.1038/srep10180

Inflammatory models drastically alter tumor growth and the immune microenvironment in hepatocellular carcinoma.

Initiation and progression of hepatocellular carcinoma (HCC) is intimately associated with a chronically diseased liver tissue. This diseased liver tissue background is a drastically different microenvironment from the healthy liver, especially with regard to immune cell prevalence and presence of mediators of immune function. To better understand the consequences of liver disease on tumor growth and the interplay with its microenvironment, we utilized two standard methods of fibrosis induction and orthotopic implantation of tumors into the inflamed and fibrotic liver to mimic the liver condition in human HCC patients. Compared to non-diseased controls, tumor growth was significantly enhanced under fibrotic conditions. The immune cells that infiltrated the tumors were also drastically different, with decreased numbers of natural killer cells but greatly increased numbers of immune-suppressive CD11b+ Gr1hi myeloid cells in both models of fibrosis. In addition, there were model-specific differences: Increased numbers of CD11b+ myeloid cells and CD4+ CD25+ T cells were found in tumors in the bile duct ligation model but not in the carbon tetrachloride model. Induction of fibrosis altered the cytokine production of implanted tumor cells, which could have farreaching consequences on the immune infiltrate and its functionality. Taken together, this work demonstrates that the combination of fibrosis induction with orthotopic tumor implantation results in a markedly different tumor microenvironment and tumor growth kinetics, emphasizing the necessity for more accurate modeling of HCC progression in mice, which takes into account the drastic changes in the tissue caused by chronic liver disease.

Authors
Markowitz, GJ; Michelotti, GA; Diehl, AM; Wang, X-F
MLA Citation
Markowitz, GJ, Michelotti, GA, Diehl, AM, and Wang, X-F. "Inflammatory models drastically alter tumor growth and the immune microenvironment in hepatocellular carcinoma." Science bulletin 60.8 (April 2015): 762-772.
PMID
26029472
Source
epmc
Published In
Science bulletin (Beijing)
Volume
60
Issue
8
Publish Date
2015
Start Page
762
End Page
772
DOI
10.1007/s11434-015-0772-5

EGF promotes mammalian cell growth by suppressing cellular senescence.

Authors
Alexander, PB; Yuan, L; Yang, P; Sun, T; Chen, R; Xiang, H; Chen, J; Wu, H; Radiloff, DR; Wang, X-F
MLA Citation
Alexander, PB, Yuan, L, Yang, P, Sun, T, Chen, R, Xiang, H, Chen, J, Wu, H, Radiloff, DR, and Wang, X-F. "EGF promotes mammalian cell growth by suppressing cellular senescence." Cell research 25.1 (January 2015): 135-138. (Letter)
PMID
25367123
Source
epmc
Published In
Cell Research
Volume
25
Issue
1
Publish Date
2015
Start Page
135
End Page
138
DOI
10.1038/cr.2014.141

Post-transcriptional regulation of MTA family by microRNAs in the context of cancer.

MicroRNAs (miRNAs) are a class of 20-24 nt small non-coding RNAs that regulate a wide range of biological processes through changing the stability and translation of their target messenger RNA (mRNA) genes. Shortly after their identification, many miRNA genes have been found dysregulated in a variety of human cancers, indicating a pathological function of this gene class in mediating cancer progression. Over the past decade, accumulated literature has shown that miRNAs participate in numerous cancer-relevant processes including cell proliferation, apoptosis, differentiation, metabolism, and importantly, metastasis, which accounts for the mortality of approximately 90 % of cancer patients. Several recent publications have linked miRNAs with metastasis-associated protein (MTA) family members. Given the fact that the MTA family members are widely overexpressed in human cancers and their nature of serving as both corepressor and coactivator in gene regulation, it is intriguing to study whether certain miRNAs regulate cancer progression through modulating the expression of MTA family members. In this review, we will focus on recent advances in understanding the regulatory relationship between certain miRNAs and MTA family members.

Authors
Zhang, Y; Wang, X-F
MLA Citation
Zhang, Y, and Wang, X-F. "Post-transcriptional regulation of MTA family by microRNAs in the context of cancer." Cancer metastasis reviews 33.4 (December 2014): 1011-1016. (Review)
PMID
25332146
Source
epmc
Published In
Cancer and Metastasis Reviews
Volume
33
Issue
4
Publish Date
2014
Start Page
1011
End Page
1016
DOI
10.1007/s10555-014-9526-0

Post-transcriptional regulation of MTA family by microRNAs in the context of cancer

Authors
Zhang, Y; Wang, X-F
MLA Citation
Zhang, Y, and Wang, X-F. "Post-transcriptional regulation of MTA family by microRNAs in the context of cancer." Cancer and Metastasis Reviews 33.4 (December 2014): 1011-1016.
Source
crossref
Published In
Cancer and Metastasis Reviews
Volume
33
Issue
4
Publish Date
2014
Start Page
1011
End Page
1016
DOI
10.1007/s10555-014-9526-0

Intrahepatic landscape of regulatory T-cell subsets in chronically HCV-infected patients with cirrhosis and HCC.

Authors
Wang, X-F; Korangy, F
MLA Citation
Wang, X-F, and Korangy, F. "Intrahepatic landscape of regulatory T-cell subsets in chronically HCV-infected patients with cirrhosis and HCC." Hepatology (Baltimore, Md.) 60.5 (November 2014): 1461-1462.
PMID
24954163
Source
epmc
Published In
Hepatology
Volume
60
Issue
5
Publish Date
2014
Start Page
1461
End Page
1462
DOI
10.1002/hep.27271

Abstract 3536: Roles of miR-215 and regulatory mechanisms for its biogenesis in response to hypoxia in glioblastoma stem cells

Authors
Hu, J; Sun, T; Wang, H; Wang, P; Fu, X-D; Li, Q-J; Wang, X-F
MLA Citation
Hu, J, Sun, T, Wang, H, Wang, P, Fu, X-D, Li, Q-J, and Wang, X-F. "Abstract 3536: Roles of miR-215 and regulatory mechanisms for its biogenesis in response to hypoxia in glioblastoma stem cells." October 1, 2014.
Source
crossref
Published In
Cancer Research
Volume
74
Issue
19 Supplement
Publish Date
2014
Start Page
3536
End Page
3536
DOI
10.1158/1538-7445.AM2014-3536

miR-33a promotes glioma-initiating cell self-renewal via PKA and NOTCH pathways.

Glioblastoma (GBM) is the most common and lethal brain tumor in adults. Glioma-initiating cells (GICs) are stem-like cells that have been implicated in glioblastoma progression and recurrence; however, the distinct properties of GICs and non-GICs within GBM tumors are largely uncharacterized. Here, we evaluated stem cell-associated microRNA (miR) expression in GICs from GBM patients and GICs derived from xenografted human glioma cell lines and determined that miR-33a promotes GIC growth and self-renewal. Moreover, evaluation of a GBM tissue array revealed that higher miR-33a expression was associated with poor prognosis of GBM patients. Antagonizing miR-33a function in GICs reduced self-renewal and tumor progression in immune-compromised mice, whereas overexpression of miR-33a in non-GICs promoted the display of features associated with GICs. We identified the mRNAs encoding phosphodiesterase 8A (PDE8A) and UV radiation resistance-associated gene (UVRAG) as direct miR-33a targets. PDE8A and UVRAG negatively regulated the cAMP/PKA and NOTCH pathways, respectively; therefore, miR-33a-dependent reduction of these proteins promoted growth and self-renewal of GICs by enhancing PKA and NOTCH activity. Furthermore, in GBM specimens, there was an inverse correlation between the expression levels of miR-33a and PDE8A and UVRAG expression. These findings reveal a miR-33a-centered signaling network that promotes GIC maintenance and has potential as a therapeutic target for GBM treatment.

Authors
Wang, H; Sun, T; Hu, J; Zhang, R; Rao, Y; Wang, S; Chen, R; McLendon, RE; Friedman, AH; Keir, ST; Bigner, DD; Li, Q-J; Wang, H; Wang, X-F
MLA Citation
Wang, H, Sun, T, Hu, J, Zhang, R, Rao, Y, Wang, S, Chen, R, McLendon, RE, Friedman, AH, Keir, ST, Bigner, DD, Li, Q-J, Wang, H, and Wang, X-F. "miR-33a promotes glioma-initiating cell self-renewal via PKA and NOTCH pathways." The Journal of clinical investigation 124.10 (October 2014): 4489-4502.
PMID
25202981
Source
epmc
Published In
Journal of Clinical Investigation
Volume
124
Issue
10
Publish Date
2014
Start Page
4489
End Page
4502
DOI
10.1172/jci75284

The hepatitis B virus-associated tumor microenvironment in hepatocellular carcinoma.

In contrast to a majority of cancer types, the initiation of hepatocellular carcinoma (HCC) is intimately associated with a chronically diseased liver tissue, with one of the most prevalent etiological factors being hepatitis B virus (HBV). Transformation of the liver in HBV-associated HCC often follows from or accompanies long-term symptoms of chronic hepatitis, inflammation and cirrhosis, and viral load is a strong predictor for both incidence and progression of HCC. Besides aiding in transformation, HBV plays a crucial role in modulating the accumulation and activation of both cellular components of the microenvironment, such as immune cells and fibroblasts, and non-cellular components of the microenvironment, such as cytokines and growth factors, markedly influencing disease progression and prognosis. This review will explore some of these components and mechanisms to demonstrate both underlying themes and the inherent complexity of these interacting systems in the initiation, progression, and metastasis of HBV-positive HCC.

Authors
Yang, P; Markowitz, GJ; Wang, X-F
MLA Citation
Yang, P, Markowitz, GJ, and Wang, X-F. "The hepatitis B virus-associated tumor microenvironment in hepatocellular carcinoma." National science review 1.3 (July 2014): 396-412.
PMID
25741453
Source
epmc
Published In
National science review
Volume
1
Issue
3
Publish Date
2014
Start Page
396
End Page
412
DOI
10.1093/nsr/nwu038

Rad17 recruits the MRE11-RAD50-NBS1 complex to regulate the cellular response to DNA double-strand breaks.

The MRE11-RAD50-NBS1 (MRN) complex is essential for the detection of DNA double-strand breaks (DSBs) and initiation of DNA damage signaling. Here, we show that Rad17, a replication checkpoint protein, is required for the early recruitment of the MRN complex to the DSB site that is independent of MDC1 and contributes to ATM activation. Mechanistically, Rad17 is phosphorylated by ATM at a novel Thr622 site resulting in a direct interaction of Rad17 with NBS1, facilitating recruitment of the MRN complex and ATM to the DSB, thereby enhancing ATM signaling. Repetition of these events creates a positive feedback for Rad17-dependent activation of MRN/ATM signaling which appears to be a requisite for the activation of MDC1-dependent MRN complex recruitment. A point mutation of the Thr622 residue of Rad17 leads to a significant reduction in MRN/ATM signaling and homologous recombination repair, suggesting that Thr622 phosphorylation is important for regulation of the MRN/ATM signaling by Rad17. These findings suggest that Rad17 plays a critical role in the cellular response to DNA damage via regulation of the MRN/ATM pathway.

Authors
Wang, Q; Goldstein, M; Alexander, P; Wakeman, TP; Sun, T; Feng, J; Lou, Z; Kastan, MB; Wang, X-F
MLA Citation
Wang, Q, Goldstein, M, Alexander, P, Wakeman, TP, Sun, T, Feng, J, Lou, Z, Kastan, MB, and Wang, X-F. "Rad17 recruits the MRE11-RAD50-NBS1 complex to regulate the cellular response to DNA double-strand breaks." The EMBO journal 33.8 (April 2014): 862-877.
PMID
24534091
Source
epmc
Published In
EMBO Journal
Volume
33
Issue
8
Publish Date
2014
Start Page
862
End Page
877
DOI
10.1002/embj.201386064

Microenvironmental regulation of cancer metastasis by miRNAs

miRNAs are a class of small, non-coding RNAs that regulate cancer progression, especially the processes of invasion and metastasis. Although earlier studies in metastasis primarily focused on the impact that miRNAs have on the intrinsic properties of cancer cells, recent reports reveal that miRNAs also shape interactions between cancer cells and their associated stroma. In this review, we discuss current known mechanisms by which miRNAs execute their microenvironmental regulation of cancer metastasis, including regulating expression of cell membrane-bound and secreted proteins or directly transmitting mature miRNAs between different cell types. The significance of miRNA-mediated tumor-stroma interactions in regulating metastasis suggests that miRNAs may be a potential therapeutic target. © 2013 Elsevier Ltd.

Authors
Zhang, Y; Yang, P; Wang, XF
MLA Citation
Zhang, Y, Yang, P, and Wang, XF. "Microenvironmental regulation of cancer metastasis by miRNAs." Trends in Cell Biology 24.3 (March 1, 2014): 153-160. (Review)
Source
scopus
Published In
Trends in Cell Biology
Volume
24
Issue
3
Publish Date
2014
Start Page
153
End Page
160
DOI
10.1016/j.tcb.2013.09.007

Microenvironmental regulation of cancer metastasis by miRNAs.

miRNAs are a class of small, non-coding RNAs that regulate cancer progression, especially the processes of invasion and metastasis. Although earlier studies in metastasis primarily focused on the impact that miRNAs have on the intrinsic properties of cancer cells, recent reports reveal that miRNAs also shape interactions between cancer cells and their associated stroma. In this review, we discuss current known mechanisms by which miRNAs execute their microenvironmental regulation of cancer metastasis, including regulating expression of cell membrane-bound and secreted proteins or directly transmitting mature miRNAs between different cell types. The significance of miRNA-mediated tumor-stroma interactions in regulating metastasis suggests that miRNAs may be a potential therapeutic target.

Authors
Zhang, Y; Yang, P; Wang, X-F
MLA Citation
Zhang, Y, Yang, P, and Wang, X-F. "Microenvironmental regulation of cancer metastasis by miRNAs." Trends Cell Biol 24.3 (March 2014): 153-160. (Review)
PMID
24125906
Source
pubmed
Published In
Trends in Cell Biology
Volume
24
Issue
3
Publish Date
2014
Start Page
153
End Page
160
DOI
10.1016/j.tcb.2013.09.007

COUP-TFII and AKT are cancer targets pursued by SCBA award winners.

This thematic issue of Cell & Bioscience highlights review articles by Sophia Y. Tsai and Ming-Jer Tsai's research team on roles of COUP-TFII in tumor progression and metastasis and by Hui-Kuan Lin and his colleagues on posttranslational regulation of Akt in human cancer. Drs. Sophia Tsai and Ming-Jer Tsai were the 2013 Society of Chinese Bioscientists in America (SCBA) Lifetime Achievement Award winners. Dr. Hui-Kuan Lin was the 2013 SCBA Outstanding Young Investigator Award winner.

Authors
Hu, J; Wang, X-F
MLA Citation
Hu, J, and Wang, X-F. "COUP-TFII and AKT are cancer targets pursued by SCBA award winners." Cell & bioscience 4.1 (January 2014): 57-.
PMID
25328663
Source
epmc
Published In
Cell and Bioscience
Volume
4
Issue
1
Publish Date
2014
Start Page
57
DOI
10.1186/2045-3701-4-57

Differential effects of Smad3 targeting in a murine model of chronic kidney disease.

Transforming growth factor (TGF)-β1 has a pivotal role in the pathogenesis of progressive kidney diseases that are characterized by fibrosis. The main intracellular signaling pathway of TGF-β1 is the Smad system, where Smad2 and Smad3 play a central role in transcriptional regulation of target genes involved in extracellular matrix (ECM) metabolism. This study analyzes the hypothesis that blockade of Smad3 attenuates the development of TGF-β1-driven renal fibrosis. This was examined in vivo in a transgenic model of TGF-β1-induced chronic kidney disease with Smad3 or without Smad3 expression and in vitro in mesangial cells and glomerular endothelial cells with Smad2/3 inhibitors or Smad3-knockdown. Electron microscopy was used for evaluation of morphological changes, real-time polymerase chain reaction for detection of RNA expression, and immunohistochemistry for localization of ECM components. Matrix metalloproteinase (MMP) level was assessed by gelatin zymography electrophoresis and located by in situ zymography. The results show TGF-β1-induced mesangial matrix expansion, tubulointerstitial fibrosis, and tubular basement membrane thickening that are attenuated by Smad3 deletion, whereas TGF-β1-induced glomerular basement membrane thickening is not shown. The amount and distribution profile of MMP-2 may suggest a role of the enzyme herein. We conclude that Smad3 targeting is not exclusively beneficial as Smad3 has diverse transcriptional regulatory effects in different cell types in the kidney.

Authors
Kellenberger, T; Krag, S; Danielsen, CC; Wang, X-F; Nyengaard, JR; Pedersen, L; Yang, C; Gao, S; Wogensen, L
MLA Citation
Kellenberger, T, Krag, S, Danielsen, CC, Wang, X-F, Nyengaard, JR, Pedersen, L, Yang, C, Gao, S, and Wogensen, L. "Differential effects of Smad3 targeting in a murine model of chronic kidney disease." Physiological reports 1.7 (December 15, 2013): e00181-.
PMID
24744860
Source
epmc
Published In
Physiological Reports
Volume
1
Issue
7
Publish Date
2013
Start Page
e00181
DOI
10.1002/phy2.181

A P(E)RM(I)T for BMP signaling.

In this issue, Xu et al. (2013) report their interesting discovery of a critical step for initiating BMP signal transduction that requires arginine methylation at the plasma membrane.

Authors
Guo, X; Wang, X-F
MLA Citation
Guo, X, and Wang, X-F. "A P(E)RM(I)T for BMP signaling." Molecular cell 51.1 (July 2013): 1-2.
PMID
23849627
Source
epmc
Published In
Molecular Cell
Volume
51
Issue
1
Publish Date
2013
Start Page
1
End Page
2
DOI
10.1016/j.molcel.2013.06.016

miR-126 and miR-126* repress recruitment of mesenchymal stem cells and inflammatory monocytes to inhibit breast cancer metastasis.

The tumour stroma is an active participant during cancer progression. Stromal cells promote tumour progression and metastasis through multiple mechanisms including enhancing tumour invasiveness and angiogenesis, and suppressing immune surveillance. We report here that miR-126/miR-126(*), a microRNA pair derived from a single precursor, independently suppress the sequential recruitment of mesenchymal stem cells and inflammatory monocytes into the tumour stroma to inhibit lung metastasis by breast tumour cells in a mouse xenograft model. miR-126/miR-126(*) directly inhibit stromal cell-derived factor-1 alpha (SDF-1α) expression, and indirectly suppress the expression of chemokine (C-C motif) ligand 2 (Ccl2) by cancer cells in an SDF-1α-dependent manner. miR-126/miR-126(*) expression is downregulated in cancer cells by promoter methylation of their host gene Egfl7. These findings determine how this microRNA pair alters the composition of the primary tumour microenvironment to favour breast cancer metastasis, and demonstrate a correlation between miR-126/126(*) downregulation and poor metastasis-free survival of breast cancer patients.

Authors
Zhang, Y; Yang, P; Sun, T; Li, D; Xu, X; Rui, Y; Li, C; Chong, M; Ibrahim, T; Mercatali, L; Amadori, D; Lu, X; Xie, D; Li, Q-J; Wang, X-F
MLA Citation
Zhang, Y, Yang, P, Sun, T, Li, D, Xu, X, Rui, Y, Li, C, Chong, M, Ibrahim, T, Mercatali, L, Amadori, D, Lu, X, Xie, D, Li, Q-J, and Wang, X-F. "miR-126 and miR-126* repress recruitment of mesenchymal stem cells and inflammatory monocytes to inhibit breast cancer metastasis." Nat Cell Biol 15.3 (March 2013): 284-294.
PMID
23396050
Source
pubmed
Published In
Nature Cell Biology
Volume
15
Issue
3
Publish Date
2013
Start Page
284
End Page
294
DOI
10.1038/ncb2690

A PK2/Bv8/PROK2 antagonist suppresses tumorigenic processes by inhibiting angiogenesis in glioma and blocking myeloid cell infiltration in pancreatic cancer.

Infiltration of myeloid cells in the tumor microenvironment is often associated with enhanced angiogenesis and tumor progression, resulting in poor prognosis in many types of cancer. The polypeptide chemokine PK2 (Bv8, PROK2) has been shown to regulate myeloid cell mobilization from the bone marrow, leading to activation of the angiogenic process, as well as accumulation of macrophages and neutrophils in the tumor site. Neutralizing antibodies against PK2 were shown to display potent anti-tumor efficacy, illustrating the potential of PK2-antagonists as therapeutic agents for the treatment of cancer. In this study we demonstrate the anti-tumor activity of a small molecule PK2 antagonist, PKRA7, in the context of glioblastoma and pancreatic cancer xenograft tumor models. For the highly vascularized glioblastoma, PKRA7 was associated with decreased blood vessel density and increased necrotic areas in the tumor mass. Consistent with the anti-angiogenic activity of PKRA7 in vivo, this compound effectively reduced PK2-induced microvascular endothelial cell branching in vitro. For the poorly vascularized pancreatic cancer, the primary anti-tumor effect of PKRA7 appears to be mediated by the blockage of myeloid cell migration/infiltration. At the molecular level, PKRA7 inhibits PK2-induced expression of certain pro-migratory chemokines and chemokine receptors in macrophages. Combining PKRA7 treatment with standard chemotherapeutic agents resulted in enhanced effects in xenograft models for both types of tumor. Taken together, our results indicate that the anti-tumor activity of PKRA7 can be mediated by two distinct mechanisms that are relevant to the pathological features of the specific type of cancer. This small molecule PK2 antagonist holds the promise to be further developed as an effective agent for combinational cancer therapy.

Authors
Curtis, VF; Wang, H; Yang, P; McLendon, RE; Li, X; Zhou, Q-Y; Wang, X-F
MLA Citation
Curtis, VF, Wang, H, Yang, P, McLendon, RE, Li, X, Zhou, Q-Y, and Wang, X-F. "A PK2/Bv8/PROK2 antagonist suppresses tumorigenic processes by inhibiting angiogenesis in glioma and blocking myeloid cell infiltration in pancreatic cancer." PLoS One 8.1 (2013): e54916-.
Website
http://hdl.handle.net/10161/4982
PMID
23372791
Source
pubmed
Published In
PloS one
Volume
8
Issue
1
Publish Date
2013
Start Page
e54916
DOI
10.1371/journal.pone.0054916

Smad3 Loss is Associated with Aortic Dilation and Spontaneous Aortic Rupture in Lean and in Obese Diabetic Db/db Mice

Authors
Biernacka, A; Gonzalez-Quesada, C; Kong, P; Rai, V; Christia, P; Dobaczewski, M; Lee, D-W; Wang, X-F; Frangogiannis, NG
MLA Citation
Biernacka, A, Gonzalez-Quesada, C, Kong, P, Rai, V, Christia, P, Dobaczewski, M, Lee, D-W, Wang, X-F, and Frangogiannis, NG. "Smad3 Loss is Associated with Aortic Dilation and Spontaneous Aortic Rupture in Lean and in Obese Diabetic Db/db Mice." November 20, 2012.
Source
wos-lite
Published In
Circulation
Volume
126
Issue
21
Publish Date
2012

TGF-β-miR-34a-CCL22 signaling-induced Treg cell recruitment promotes venous metastases of HBV-positive hepatocellular carcinoma.

Portal vein tumor thrombus (PVTT) is strongly correlated to a poor prognosis for patients with hepatocellular carcinoma (HCC). In this study, we uncovered a causative link between hepatitis B virus (HBV) infection and development of PVTT. Mechanistically, elevated TGF-β activity, associated with the persistent presence of HBV in the liver tissue, suppresses the expression of microRNA-34a, leading to enhanced production of chemokine CCL22, which recruits regulatory T (Treg) cells to facilitate immune escape. These findings strongly suggest that HBV infection and activity of the TGF-β-miR-34a-CCL22 axis serve as potent etiological factors to predispose HCC patients for the development of PVTT, possibly through the creation of an immune-subversive microenvironment to favor colonization of disseminated HCC cells in the portal venous system.

Authors
Yang, P; Li, Q-J; Feng, Y; Zhang, Y; Markowitz, GJ; Ning, S; Deng, Y; Zhao, J; Jiang, S; Yuan, Y; Wang, H-Y; Cheng, S-Q; Xie, D; Wang, X-F
MLA Citation
Yang, P, Li, Q-J, Feng, Y, Zhang, Y, Markowitz, GJ, Ning, S, Deng, Y, Zhao, J, Jiang, S, Yuan, Y, Wang, H-Y, Cheng, S-Q, Xie, D, and Wang, X-F. "TGF-β-miR-34a-CCL22 signaling-induced Treg cell recruitment promotes venous metastases of HBV-positive hepatocellular carcinoma." Cancer Cell 22.3 (September 11, 2012): 291-303.
PMID
22975373
Source
pubmed
Published In
Cancer Cell
Volume
22
Issue
3
Publish Date
2012
Start Page
291
End Page
303
DOI
10.1016/j.ccr.2012.07.023

Bat3 facilitates H3K79 dimethylation by DOT1L and promotes DNA damage-induced 53BP1 foci at G1/G2 cell-cycle phases.

The methyltransferase DOT1L methylates histone H3 at K79 to facilitate specific biological events. H3K79 dimethylation (H3K79-2Me) by DOT1L influences the DNA damage response by promoting 53BP1 recruitment to DNA damage sites; however, it is unclear if this methylation is required as 53BP1 interacts with dimethylated H4 (H4K20-2Me) with a much higher affinity. We demonstrate that H3K79-2Me, while negligible during S-phase, is required for ionizing radiation (IR)-induced 53BP1 foci formation during G1/G2-phases when H4K20-2Me levels are low. Further, we describe an essential role for HLA-B-associated transcript 3 (Bat3) in regulating this process in U2OS cells. Bat3 co-localizes with DOT1L at histone H3, and Bat3 knockdown results in decreased DOT1L-H3 interaction and H3K79-2Me, leading to a reduction in IR-induced 53BP1 foci formation, defects in DNA repair and increased sensitivity to IR. We demonstrate that a conserved Bat3 ubiquitin-like motif and a conserved DOT1L ubiquitin-interacting motif promote DOT1L-Bat3 interaction to facilitate efficient H3K79-2Me and IR-induced 53BP1 foci formation during G1/G2-phases. Taken together, our findings identify a novel role for Bat3 in regulating DOT1L function, which plays a critical role in DNA damage response.

Authors
Wakeman, TP; Wang, Q; Feng, J; Wang, X-F
MLA Citation
Wakeman, TP, Wang, Q, Feng, J, and Wang, X-F. "Bat3 facilitates H3K79 dimethylation by DOT1L and promotes DNA damage-induced 53BP1 foci at G1/G2 cell-cycle phases." EMBO J 31.9 (May 2, 2012): 2169-2181.
PMID
22373577
Source
pubmed
Published In
EMBO Journal
Volume
31
Issue
9
Publish Date
2012
Start Page
2169
End Page
2181
DOI
10.1038/emboj.2012.50

TGFΒ/Smad3 signal pathway is not required for epidermal langerhans cell development

Authors
Xu, Y-P; Shi, Y; Cui, Z-Z; Jiang, HH; Li, L; Wang, X-F; Zhou, L; Mi, Q-S
MLA Citation
Xu, Y-P, Shi, Y, Cui, Z-Z, Jiang, HH, Li, L, Wang, X-F, Zhou, L, and Mi, Q-S. "TGFΒ/Smad3 signal pathway is not required for epidermal langerhans cell development." Journal of Investigative Dermatology 132.8 (2012): 2106-2109.
PMID
22437318
Source
scival
Published In
Journal of Investigative Dermatology
Volume
132
Issue
8
Publish Date
2012
Start Page
2106
End Page
2109
DOI
10.1038/jid.2012.71

A mediator lost in the war on cancer

An unexpected role for a Mediator subunit, MED12, in resistance to multiple anticancer agents is revealed by Huang et al. Loss of MED12 confers drug resistance by activating transforming growth factor β (TGF-β) signaling. Inhibition of the TGF-β pathway resensitizes cells to therapeutic drugs, suggesting a new combinatorial cancer treatment. © 2012 Elsevier Inc.

Authors
Guo, X; Wang, X-F
MLA Citation
Guo, X, and Wang, X-F. "A mediator lost in the war on cancer." Cell 151.5 (2012): 927-929.
PMID
23178113
Source
scival
Published In
Cell
Volume
151
Issue
5
Publish Date
2012
Start Page
927
End Page
929
DOI
10.1016/j.cell.2012.11.003

A pentapeptide monocyte locomotion inhibitory factor protects brain ischemia injury by targeting the eEF1A1/endothelial nitric oxide synthase pathway

BACKGROUND AND PURPOSE-: Ischemic stroke is a major cause of death worldwide but lacks viable treatment or treatment targets. Monocyte locomotion inhibitory factor (MLIF) is a small heat-stable pentapeptide produced by Entamoeba histolytica in axenic culture, which is supposed to protect the brain from ischemic injury; the mechanism, however, remains unknown. In this study, we further investigated the mechanism underlying the protective role of MLIF in brain ischemia. METHODS-: A middle cerebral artery occlusion model in rats was used for detecting the effect of MLIF in the brain ischemia in vivo. To identify targets of MLIF in brain endothelial cells, we performed immunoprecipitation of biotin-conjugated MLIF and mass spectrometry. RESULTS-: MLIF can protect the brain from ischemic injury in vivo, yielding decreased ischemic volume, prolonged survival, and improved neurological outcome. In vitro studies showed that MLIF displayed protective effects through inhibition of expression of pathological inflammatory adhesion molecules and enhancing endothelial nitric oxide synthase expression and nitric oxide release in the cerebrovascular endothelium. The target screening experiments demonstrated binding of MLIF to the ribosomal protein translation elongation factor eEF1A1. MLIF enhanced endothelial nitric oxide synthase expression through stabilization of endothelial nitric oxide synthase mRNA, and eEF1A1 was shown to be necessary for this enhanced expression. Knockdown of eEF1A1 or inhibition of endothelial nitric oxide synthase attenuated MLIF-mediated inhibition of adhesion molecule expression. CONCLUSIONS-: In this study, we identified a new potential pharmacologically targetable mechanism underlying MLIF's protective effects in brain ischemia through the eEF1A1/endothelial nitric oxide synthase pathway. © 2012 American Heart Association, Inc.

Authors
Zhang, Y; Chen, J; Li, F; Li, D; Xiong, Q; Lin, Y; Zhang, D; Wang, X-F; Yang, P; Rui, Y-C
MLA Citation
Zhang, Y, Chen, J, Li, F, Li, D, Xiong, Q, Lin, Y, Zhang, D, Wang, X-F, Yang, P, and Rui, Y-C. "A pentapeptide monocyte locomotion inhibitory factor protects brain ischemia injury by targeting the eEF1A1/endothelial nitric oxide synthase pathway." Stroke 43.10 (2012): 2764-2773.
PMID
22829547
Source
scival
Published In
Stroke
Volume
43
Issue
10
Publish Date
2012
Start Page
2764
End Page
2773
DOI
10.1161/STROKEAHA.112.657908

New secrets behind bone metastasis

Secreted proteins play essential roles in every step of cancer metastasis, while the identities and functions of those that contribute to tissue-specific metastasis are largely uncharacterized. Two articles in Cell Research report the discovery and functional analyses of novel secreted proteins that are biologically and clinically relevant to bone metastasis. The combinatory approaches represented here, together with advances in related technology, will promise a better understanding of the cancer secretome. © 2012 IBCB, SIBS, CAS All rights reserved.

Authors
Guo, X; Wang, X-F
MLA Citation
Guo, X, and Wang, X-F. "New secrets behind bone metastasis." Cell Research 22.9 (2012): 1309-1311.
PMID
22785562
Source
scival
Published In
Cell Research
Volume
22
Issue
9
Publish Date
2012
Start Page
1309
End Page
1311
DOI
10.1038/cr.2012.99

A novel, non-apoptotic role for Scythe/BAT3: A functional switch between the pro- and anti-proliferative roles of p21 during the cell cycle

Background: Scythe/BAT3 is a member of the BAG protein family whose role in apoptosis has been extensively studied. However, since the developmental defects observed in Bat3-null mouse embryos cannot be explained solely by defects in apoptosis, we investigated whether BAT3 is also involved in cell-cycle progression. Methods/Principal Findings: Using a stable-inducible Bat3-knockdown cellular system, we demonstrated that reduced BAT3 protein level causes a delay in both G1/S transition and G2/M progression. Concurrent with these changes in cell-cycle progression, we observed a reduction in the turnover and phosphorylation of the CDK inhibitor p21, which is best known as an inhibitor of DNA replication; however, phosphorylated p21 has also been shown to promote G2/M progression. Our findings indicate that in Bat3-knockdown cells, p21 continues to be synthesized during cell-cycle phases that do not normally require p21, resulting in p21 protein accumulation and a subsequent delay in cell-cycle progression. Finally, we showed that BAT3 co-localizes with p21 during the cell cycle and is required for the translocation of p21 from the cytoplasm to the nucleus during the G1/S transition and G2/M progression. Conclusion: Our study reveals a novel, non-apoptotic role for BAT3 in cell-cycle regulation. By maintaining a low p21 protein level during the G1/S transition, BAT3 counteracts the inhibitory effect of p21 on DNA replication and thus enables the cells to progress from G1 to S phase. Conversely, during G2/M progression, BAT3 facilitates p21 phosphorylation by cyclin A/Cdk2, an event required for G2/M progression. BAT3 modulates these pro- and anti-proliferative roles of p21 at least in part by regulating cyclin A abundance, as well as p21 translocation between the cytoplasm and the nucleus to ensure that it functions in the appropriate intracellular compartment during each phase of the cell cycle. © 2012 Yong, Wang.

Authors
Yong, ST; Wang, X-F
MLA Citation
Yong, ST, and Wang, X-F. "A novel, non-apoptotic role for Scythe/BAT3: A functional switch between the pro- and anti-proliferative roles of p21 during the cell cycle." PLoS ONE 7.6 (2012).
Website
http://hdl.handle.net/10161/4958
PMID
22761665
Source
scival
Published In
PloS one
Volume
7
Issue
6
Publish Date
2012
DOI
10.1371/journal.pone.0038085

Where PI3K/Akt meets smads: The crosstalk determines human embryonic stem cell fate

Coordinated interactions between signaling networks govern the balance of cell fate decisions in human embryonic stem cells. In this issue, Singh et al. (2012) report that PI3K/Akt signaling switches Activin/Smad activity between pro-self-renewal and prodifferentiation by regulating ERK and GSK3β/β-catenin signaling. © 2012 Elsevier Inc.

Authors
Chen, Y-G; Li, Z; Wang, X-F
MLA Citation
Chen, Y-G, Li, Z, and Wang, X-F. "Where PI3K/Akt meets smads: The crosstalk determines human embryonic stem cell fate." Cell Stem Cell 10.3 (2012): 231-232.
PMID
22385648
Source
scival
Published In
Cell Stem Cell
Volume
10
Issue
3
Publish Date
2012
Start Page
231
End Page
232
DOI
10.1016/j.stem.2012.02.008

TGF-beta/Smad3 Activation in the Diabetic Mouse Heart Induces Fibrotic Cardiac Remodeling and Diastolic Dysfunction While Protecting From Excessive Matrix Degradation and Preventing the Development of Systolic Dysfunction

Authors
Biernacka, A; Gonzalez-Quesada, C; Tian, Q; Li, N; Dobaczewski, M; Wang, X-F; Frangogiannis, NG
MLA Citation
Biernacka, A, Gonzalez-Quesada, C, Tian, Q, Li, N, Dobaczewski, M, Wang, X-F, and Frangogiannis, NG. "TGF-beta/Smad3 Activation in the Diabetic Mouse Heart Induces Fibrotic Cardiac Remodeling and Diastolic Dysfunction While Protecting From Excessive Matrix Degradation and Preventing the Development of Systolic Dysfunction." November 22, 2011.
Source
wos-lite
Published In
Circulation
Volume
124
Issue
21
Publish Date
2011

Abstract 2482: Bat3 facilitates histone H3 lysine 79 dimethylation by DOT1L to promote ionizing radiation-induced 53BP1 foci formation during G1- and G2-phases of the cell cycle

Authors
Wakeman, TP; Feng, J; Wang, X-F
MLA Citation
Wakeman, TP, Feng, J, and Wang, X-F. "Abstract 2482: Bat3 facilitates histone H3 lysine 79 dimethylation by DOT1L to promote ionizing radiation-induced 53BP1 foci formation during G1- and G2-phases of the cell cycle." Cancer Research 71.8 Supplement (April 15, 2011): 2482-2482.
Source
crossref
Published In
Cancer Research
Volume
71
Issue
8 Supplement
Publish Date
2011
Start Page
2482
End Page
2482
DOI
10.1158/1538-7445.AM2011-2482

Abstract 3311: IL6-Stat3 signaling promotes glioma stem cell (GSC) survival under hypoxia environment through inhibition of cell-death inducing gene Bnip3

Authors
Wang, H; Wang, X-F; Rich, J; Wang, Q; Hjelmeland, A
MLA Citation
Wang, H, Wang, X-F, Rich, J, Wang, Q, and Hjelmeland, A. "Abstract 3311: IL6-Stat3 signaling promotes glioma stem cell (GSC) survival under hypoxia environment through inhibition of cell-death inducing gene Bnip3." Cancer Research 71.8 Supplement (April 15, 2011): 3311-3311.
Source
crossref
Published In
Cancer Research
Volume
71
Issue
8 Supplement
Publish Date
2011
Start Page
3311
End Page
3311
DOI
10.1158/1538-7445.AM2011-3311

Genome variation in Cryptococcus gattii, an emerging pathogen of immunocompetent hosts

Cryptococcus gattii recently emerged as the causative agent of cryptococcosis in healthy individuals in western North America, despite previous characterization of the fungus as a pathogen in tropical or subtropical regions. As a foundation to study the genetics of virulence in this pathogen, we sequenced the genomes of a strain (WM276) representing the predominant global molecular type (VGI) and a clinical strain (R265) of the major genotype (VGIIa) causing disease in North America. We compared these C. gattii genomes with each other and with the genomes of representative strains of the two varieties of Cryptococcus neoformans that generally cause disease in immunocompromised people. Our comparisons included chromosome alignments, analysis of gene content and gene family evolution, and comparative genome hybridization (CGH). These studies revealed that the genomes of the two representative C. gattii strains (genotypes VGI and VGIIa) are colinear for the majority of chromosomes, with some minor rearrangements. However, multiortholog phylogenetic analysis and an evaluation of gene/sequence conservation support the existence of speciation within the C. gattii complex. More extensive chromosome rearrangements were observed upon comparison of the C. gattii and the C. neoformans genomes. Finally, CGH revealed considerable variation in clinical and environmental isolates as well as changes in chromosome copy numbers in C. gattii isolates displaying fluconazole heteroresistance. © 2011 D'Souza et al.

Authors
D'Souza, CA; Kronstad, JW; Taylor, G; Warren, R; Yuen, M; Hu, G; Jung, WH; Sham, A; Kidd, SE; Tangen, K; Lee, N; Zeilmaker, T; Sawkins, J; McVicker, G; Shah, S; Gnerre, S; Griggs, A; Zeng, Q; Bartlett, K; Li, W; Wang, X; Heitman, J; Stajich, JE; Fraser, JA; Meyer, W; Carter, D; Schein, J; Krzywinski, M; Kwon-Chung, KJ; Varma, A; Wang, J; Brunham, R; Fyfe, M; Ouellette, BFF; Siddiqui, A; Marra, M; Jones, S; Holt, R; Birren, BW; Galagan, JE; Cuomoe, CA
MLA Citation
D'Souza, CA, Kronstad, JW, Taylor, G, Warren, R, Yuen, M, Hu, G, Jung, WH, Sham, A, Kidd, SE, Tangen, K, Lee, N, Zeilmaker, T, Sawkins, J, McVicker, G, Shah, S, Gnerre, S, Griggs, A, Zeng, Q, Bartlett, K, Li, W, Wang, X, Heitman, J, Stajich, JE, Fraser, JA, Meyer, W, Carter, D, Schein, J, Krzywinski, M, Kwon-Chung, KJ, Varma, A, Wang, J, Brunham, R, Fyfe, M, Ouellette, BFF, Siddiqui, A, Marra, M, Jones, S, Holt, R, Birren, BW, Galagan, JE, and Cuomoe, CA. "Genome variation in Cryptococcus gattii, an emerging pathogen of immunocompetent hosts." mBio 2.1 (2011).
PMID
21304167
Source
scival
Published In
mBio
Volume
2
Issue
1
Publish Date
2011
DOI
10.1128/mBio.00342-10

Trefoil factor 1 acts to suppress senescence induced by oncogene activation during the cellular transformation process

Senescence is a cellular stress response characterized by persistent cell growth arrest under various stress conditions, including oncogene activation or tumor suppressor loss, which functions as a critical barrier that must be overcome to allow the progression from a precancerous or preinvasive lesion to a malignant tumor. Trefoil factor 1 (TFF1) is a secreted protein involved in maintaining the gastrointestinal epithelium by serving a tumor-suppressive role; however, TFF1 is overexpressed in several types of cancers. Here we report that TFF1 acts as a promoter of tumorigenesis in the context of prostate and pancreatic cancers by suppressing oncogene-induced senescence (OIS). Expression of TFF1 allows human prostate epithelial cells to escape OIS caused by the activated Ras oncogene or by reduced expression of the tumor suppressor PTEN, in part by the involvement of the EGF receptor-mediated pathway and inhibition of the expression of the cell cycle regulator p21. Without intrinsic promitogenic activity TFF1 may act in both autocrine and paracrine manners to enable cells to undergo the initial transformation and expansion against the restrictive microenvironment during early stage tumorigenesis. Taken together, our findings identify TFF1 as a soluble factor designed to act mainly to antagonize the OIS process to accelerate tumorigenesis.

Authors
Radiloff, DR; Wakemana, TP; Feng, J; Schilling, S; Seto, E; Wang, X-F
MLA Citation
Radiloff, DR, Wakemana, TP, Feng, J, Schilling, S, Seto, E, and Wang, X-F. "Trefoil factor 1 acts to suppress senescence induced by oncogene activation during the cellular transformation process." Proceedings of the National Academy of Sciences of the United States of America 108.16 (2011): 6591-6596.
PMID
21451135
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
108
Issue
16
Publish Date
2011
Start Page
6591
End Page
6596
DOI
10.1073/pnas.1017269108

Sorafenib suppresses postsurgical recurrence and metastasis of hepatocellular carcinoma in an orthotopic mouse model

Surgical resection is the first-line treatment for hepatocellular carcinoma (HCC) patients with well-preserved liver function. Nevertheless, the rate of postoperative recurrence at 5 years is as high as 70%, and this gravely jeopardizes the therapeutic outcome. Clearly, new approaches are needed for preventing the relapse of this deadly disease. Taking advantage of a luciferase-labeled orthotopic xenograft model of HCC, we examined the role of sorafenib, the first systemic drug approved for advanced HCC patients, in the prevention of HCC recurrence. We found that sorafenib suppressed the development of postsurgical intrahepatic recurrence and abdominal metastasis and consequently led to prolonged postoperative survival of mice in this model. Furthermore, hyperactivity of extracellular signal-regulated kinase signaling caused by elevated levels of growth factors associated with postoperative liver regeneration enhanced the sensitivity of HCC cells to sorafenib; this provides a plausible explanation for the observation that recurrent tumors are more responsive to growth inhibition by sorafenib. Conclusion: Our results strongly suggest that by effectively reducing postoperative recurrence, sorafenib has a potential application in early-stage HCC patients who have undergone hepatectomy with curative intention. © 2010 American Association for the Study of Liver Diseases.

Authors
Feng, Y-X; Wang, T; Deng, Y-Z; Yang, P; Li, J-J; Guan, D-X; Yao, F; Zhu, Y-Q; Qin, Y; Wang, H; Li, N; Wu, M-C; Wang, H-Y; Wang, X-F; Cheng, S-Q; Xie, D
MLA Citation
Feng, Y-X, Wang, T, Deng, Y-Z, Yang, P, Li, J-J, Guan, D-X, Yao, F, Zhu, Y-Q, Qin, Y, Wang, H, Li, N, Wu, M-C, Wang, H-Y, Wang, X-F, Cheng, S-Q, and Xie, D. "Sorafenib suppresses postsurgical recurrence and metastasis of hepatocellular carcinoma in an orthotopic mouse model." Hepatology 53.2 (2011): 483-492.
PMID
21274870
Source
scival
Published In
Hepatology
Volume
53
Issue
2
Publish Date
2011
Start Page
483
End Page
492
DOI
10.1002/hep.24075

Dopamine and α-synuclein dysfunction in Smad3 null mice

Background: Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration in the substantia nigra (SN). Transforming growth factor-1 (TGF-1) levels increase in patients with PD, although the effects of this increment remain unclear. We have examined the mesostriatal system in adult mice deficient in Smad3, a molecule involved in the intracellular TGF-1 signalling cascade. Results: Striatal monoamine oxidase (MAO)-mediated dopamine (DA) catabolism to 3,4-dihydroxyphenylacetic acid (DOPAC) is strongly increased, promoting oxidative stress that is reflected by an increase in glutathione levels. Fewer astrocytes are detected in the ventral midbrain (VM) and striatal matrix, suggesting decreased trophic support to dopaminergic neurons. The SN of these mice has dopaminergic neuronal degeneration in its rostral portion, and the pro-survival Erk1/2 signalling is diminished in nigra dopaminergic neurons, not associated with alterations to p-JNK or p-p38. Furthermore, inclusions of α-synuclein are evident in selected brain areas, both in the perikaryon (SN and paralemniscal nucleus) or neurites (motor and cingulate cortices, striatum and spinal cord). Interestingly, these α-synuclein deposits are detected with ubiquitin and PS129 α-synuclein in a core/halo cellular distribution, which resemble those observed in human Lewy bodies (LB). Conclusions: Smad3 deficiency promotes strong catabolism of DA in the striatum (ST), decrease trophic and astrocytic support to dopaminergic neurons and may induce α-synuclein aggregation, which may be related to early parkinsonism. These data underline a role for Smad3 in α-synuclein and DA homeostasis, and suggest that modulatory molecules of this signalling pathway should be evaluated as possible neuroprotective agents. © 2011 Tapia-González et al; licensee BioMed Central Ltd.

Authors
Tapia-González, S; Giráldez-Pérez, RM; Cuartero, MI; Casarejos, MJ; Mena, MÁ; Wang, X-F; Sánchez-Capelo, A
MLA Citation
Tapia-González, S, Giráldez-Pérez, RM, Cuartero, MI, Casarejos, MJ, Mena, MÁ, Wang, X-F, and Sánchez-Capelo, A. "Dopamine and α-synuclein dysfunction in Smad3 null mice." Molecular Neurodegeneration 6.1 (2011).
PMID
21995845
Source
scival
Published In
Molecular Neurodegeneration
Volume
6
Issue
1
Publish Date
2011
DOI
10.1186/1750-1326-6-72

Dopamine and α-synuclein dysfunction in Smad3 null mice.

Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration in the substantia nigra (SN). Transforming growth factor-β1 (TGF-β1) levels increase in patients with PD, although the effects of this increment remain unclear. We have examined the mesostriatal system in adult mice deficient in Smad3, a molecule involved in the intracellular TGF-β1 signalling cascade. Striatal monoamine oxidase (MAO)-mediated dopamine (DA) catabolism to 3,4-dihydroxyphenylacetic acid (DOPAC) is strongly increased, promoting oxidative stress that is reflected by an increase in glutathione levels. Fewer astrocytes are detected in the ventral midbrain (VM) and striatal matrix, suggesting decreased trophic support to dopaminergic neurons. The SN of these mice has dopaminergic neuronal degeneration in its rostral portion, and the pro-survival Erk1/2 signalling is diminished in nigra dopaminergic neurons, not associated with alterations to p-JNK or p-p38. Furthermore, inclusions of α-synuclein are evident in selected brain areas, both in the perikaryon (SN and paralemniscal nucleus) or neurites (motor and cingulate cortices, striatum and spinal cord). Interestingly, these α-synuclein deposits are detected with ubiquitin and P(S129)-α-synuclein in a core/halo cellular distribution, which resemble those observed in human Lewy bodies (LB). Smad3 deficiency promotes strong catabolism of DA in the striatum (ST), decrease trophic and astrocytic support to dopaminergic neurons and may induce α-synuclein aggregation, which may be related to early parkinsonism. These data underline a role for Smad3 in α-synuclein and DA homeostasis, and suggest that modulatory molecules of this signalling pathway should be evaluated as possible neuroprotective agents.

Authors
Tapia-González, S; Giráldez-Pérez, RM; Cuartero, MI; Casarejos, MJ; Mena, MÁ; Wang, X-F; Sánchez-Capelo, A
MLA Citation
Tapia-González, S, Giráldez-Pérez, RM, Cuartero, MI, Casarejos, MJ, Mena, MÁ, Wang, X-F, and Sánchez-Capelo, A. "Dopamine and α-synuclein dysfunction in Smad3 null mice." Molecular neurodegeneration 6 (2011): 72--.
Source
scival
Published In
Molecular Neurodegeneration
Volume
6
Publish Date
2011
Start Page
72-
DOI
10.1186/1750-1326-6-72

Tumor initiating cells in esophageal squamous cell carcinomas express high levels of CD44.

BACKGROUND: Esophageal Squamous Cell Carcinoma (ESCC) is a major subtype of esophageal cancer causing significant morbility and mortality in Asia. Mechanism of initiation and progression of this disease is unclear. Tumor initiating cells (TICs) are the subpopulation of cells which have the ability to self-renew, as well as, to drive initiation and progression of cancer. Increasing evidence has shown that TICs exist in a variety of tumors. However, the identification and characterization of TICs in esophageal carcinoma has remained elusive. METHODOLOGY/PRINCIPAL FINDINGS: to identify TICs in ESCC, ESCC cell lines including two primary cells were used for screening suitable surface marker. Then colony formation assay, drug resistant assay and tumorigenicity assay in immune deficient mice were used to characterize TICs in ESCC. We found that just the CD44 expression correlated with tumorigenicity in ESCC cell lines. And then induced differentiation of ESCC cells by all-trans retinoic acid treatment led to decreased expression of CD44. The FACS isolated cell subpopulations with high CD44 expression showed increased colony formation and drug resistance in vitro, as well as significantly enhanced tumorigenicity in NOD/SICD mice, as compared to the low expressing CD44 ESCC cells. CONCLUSIONS/SIGNIFICANCE: our study has discovered a novel TIC surface marker, CD44, which can be utilized to enrich efficiently the TICs in ESCC. These findings will be useful for further studies of these cells and exploring therapeutic approaches.

Authors
Zhao, J-S; Li, W-J; Ge, D; Zhang, P-J; Li, J-J; Lu, C-L; Ji, X-D; Guan, D-X; Gao, H; Xu, L-Y; Li, E-M; Soukiasian, H; Koeffler, HP; Wang, X-F; Xie, D
MLA Citation
Zhao, J-S, Li, W-J, Ge, D, Zhang, P-J, Li, J-J, Lu, C-L, Ji, X-D, Guan, D-X, Gao, H, Xu, L-Y, Li, E-M, Soukiasian, H, Koeffler, HP, Wang, X-F, and Xie, D. "Tumor initiating cells in esophageal squamous cell carcinomas express high levels of CD44." PLoS One 6.6 (2011): e21419-.
PMID
21731740
Source
pubmed
Published In
PloS one
Volume
6
Issue
6
Publish Date
2011
Start Page
e21419
DOI
10.1371/journal.pone.0021419

Smad3 signaling critically regulates fibroblast phenotype and function in healing myocardial infarction

Rationale: Cardiac fibroblasts are key effector cells in the pathogenesis of cardiac fibrosis. Transforming growth factor (TGF)-β/Smad3 signaling is activated in the border zone of healing infarcts and induces fibrotic remodeling of the infarcted ventricle contributing to the development of diastolic dysfunction. Objective: The present study explores the mechanisms responsible for the fibrogenic effects of Smad3 by dissecting its role in modulating cardiac fibroblast phenotype and function. Methods and Results: Smad3 null mice and corresponding wild-type controls underwent reperfused myocardial infarction protocols. Surprisingly, reduced collagen deposition in Smad3-/-infarcts was associated with increased infiltration with myofibroblasts. In vitro studies demonstrated that TGF-β1 inhibited murine cardiac fibroblast proliferation; these antiproliferative effects were mediated via Smad3. Smad3-/-fibroblasts were functionally defective, exhibiting impaired collagen lattice contraction when compared with wild-type cells. Decreased contractile function was associated with attenuated TGF-β-induced expression of α-smooth muscle actin. In addition, Smad3-/- fibroblasts had decreased migratory activity on stimulation with serum, and exhibited attenuated TGF-β1-induced upregulation of extracellular matrix protein synthesis. Upregulation of connective tissue growth factor, an essential downstream mediator in TGF-β-induced fibrosis, was in part dependent on Smad3. Connective tissue growth factor stimulation enhanced extracellular matrix protein expression by cardiac fibroblasts in a Smad3-independent manner. Conclusions: Disruption of Smad3 results in infiltration of the infarct with abundant hypofunctional fibroblasts that exhibit impaired myofibroblast transdifferentiation, reduced migratory potential, and suppressed expression of fibrosis-associated genes. © 2010 American Heart Association, Inc.

Authors
Dobaczewski, M; Bujak, M; Li, N; Gonzalez-Quesada, C; Mendoza, LH; Wang, XF; Frangogiannis, NG
MLA Citation
Dobaczewski, M, Bujak, M, Li, N, Gonzalez-Quesada, C, Mendoza, LH, Wang, XF, and Frangogiannis, NG. "Smad3 signaling critically regulates fibroblast phenotype and function in healing myocardial infarction." Circulation Research 107.3 (August 6, 2010): 418-428.
PMID
20522804
Source
scopus
Published In
Circulation Research
Volume
107
Issue
3
Publish Date
2010
Start Page
418
End Page
428
DOI
10.1161/CIRCRESAHA.109.216101

Notch promotes radioresistance of glioma stem cells.

Radiotherapy represents the most effective nonsurgical treatments for gliomas. However, gliomas are highly radioresistant and recurrence is nearly universal. Results from our laboratory and other groups suggest that cancer stem cells contribute to radioresistance in gliomas and breast cancers. The Notch pathway is critically implicated in stem cell fate determination and cancer. In this study, we show that inhibition of Notch pathway with gamma-secretase inhibitors (GSIs) renders the glioma stem cells more sensitive to radiation at clinically relevant doses. GSIs enhance radiation-induced cell death and impair clonogenic survival of glioma stem cells but not non-stem glioma cells. Expression of the constitutively active intracellular domains of Notch1 or Notch2 protect glioma stem cells against radiation. Notch inhibition with GSIs does not alter the DNA damage response of glioma stem cells after radiation but rather reduces Akt activity and Mcl-1 levels. Finally, knockdown of Notch1 or Notch2 sensitizes glioma stem cells to radiation and impairs xenograft tumor formation. Taken together, our results suggest a critical role of Notch signaling to regulate radioresistance of glioma stem cells. Inhibition of Notch signaling holds promise to improve the efficiency of current radiotherapy in glioma treatment.

Authors
Wang, J; Wakeman, TP; Lathia, JD; Hjelmeland, AB; Wang, X-F; White, RR; Rich, JN; Sullenger, BA
MLA Citation
Wang, J, Wakeman, TP, Lathia, JD, Hjelmeland, AB, Wang, X-F, White, RR, Rich, JN, and Sullenger, BA. "Notch promotes radioresistance of glioma stem cells." Stem Cells 28.1 (January 2010): 17-28.
PMID
19921751
Source
pubmed
Published In
Stem Cells
Volume
28
Issue
1
Publish Date
2010
Start Page
17
End Page
28
DOI
10.1002/stem.261

Proteolysis of Rad17 by Cdh1/APC regulates checkpoint termination and recovery from genotoxic stress

Recent studies have shown a critical function for the ubiquitin-proteasome system (UPS) in regulating the signalling network for DNA damage responses and DNA repair. To search for new UPS targets in the DNA damage signalling pathway, we have carried out a non-biased assay to identify fast-turnover proteins induced by various types of genotoxic stress. This endeavour led to the identification of Rad17 as a protein exhibiting a distinctive pattern of upregulation followed by subsequent degradation after exposure to UV radiation in human primary cells. Our characterization showed that UV-induced Rad17 oscillation is mediated by Cdh1/APC, a ubiquitin-protein ligase. Studies using a degradation-resistant Rad17 mutant demonstrated that Rad17 stabilization prevents the termination of checkpoint signalling, which in turn attenuates the cellular re-entry into cell-cycle progression. The findings provide an insight into how the proteolysis of Rad17 by Cdh1/APC regulates the termination of checkpoint signalling and the recovery from genotoxic stress. © 2010 European Molecular Biology Organization.

Authors
Zhang, L; Park, C-H; Wu, J; Kim, H; Liu, W; Fujita, T; Balasubramani, M; Schreiber, EM; Wang, X-F; Wan, Y
MLA Citation
Zhang, L, Park, C-H, Wu, J, Kim, H, Liu, W, Fujita, T, Balasubramani, M, Schreiber, EM, Wang, X-F, and Wan, Y. "Proteolysis of Rad17 by Cdh1/APC regulates checkpoint termination and recovery from genotoxic stress." EMBO Journal 29.10 (2010): 1726-1737.
PMID
20424596
Source
scival
Published In
EMBO Journal
Volume
29
Issue
10
Publish Date
2010
Start Page
1726
End Page
1737
DOI
10.1038/emboj.2010.55

Liver cancer: EphrinA2 promotes tumorigenicity through Rac1/Akt/NF-κB signaling pathway

Eph/Ephrin family, one of the largest receptor tyrosine kinase families, has been extensively studied in morphogenesis and neural development. Recently, growing attention has been paid to its role in the initiation and progression of various cancers. However, the role of Eph/Ephrins in hepatocellular carcinoma (HCC) has been rarely investigated. In this study, we found that the expression of EphrinA2 was significantly up-regulated in both established cell lines and clinical tissue samples of HCC, and the most significant increase was observed in the tumors invading the portal veins. Forced expression of EphrinA2 in HCC cells significantly promoted in vivo tumorigenicity, whereas knockdown of this gene inhibited this oncogenic effect.Wefurther found that suppression of apoptosis, rather than accelerating proliferation, was responsible for EphrinA2-enhanced tumorigenicity. In addition, EphrinA2 endowed cancer cells with resistance to tumor necrosis factor alpha (TNF-α)-induced apoptosis, thus facilitating their survival. Furthermore, we disclosed a novel EphrinA2/ras-related c3 botulinum toxin substrate 1 (Rac1)/V-akt murine thymoma viral oncogene homolog (Akt)/nuclear factor-kappa B (NF-κB) pathway contributing to the inhibitory effect on apoptosis inHCCcells. Conclusion: This study revealed that EphrinA2 played an important role in the development and progression ofHCCby promoting the survival of cancer cells, indicating its role as a potential therapeutic target in HCC. Copyright © 2009 by the American Association for the Study of Liver Diseases.

Authors
Feng, Y-X; Zhao, J-S; Li, J-J; Wang, T; Cheng, S-Q; Yuan, Y; Wang, F; Wang, X-F; Xie, D
MLA Citation
Feng, Y-X, Zhao, J-S, Li, J-J, Wang, T, Cheng, S-Q, Yuan, Y, Wang, F, Wang, X-F, and Xie, D. "Liver cancer: EphrinA2 promotes tumorigenicity through Rac1/Akt/NF-κB signaling pathway." Hepatology 51.2 (2010): 535-544.
PMID
19918976
Source
scival
Published In
Hepatology
Volume
51
Issue
2
Publish Date
2010
Start Page
535
End Page
544
DOI
10.1002/hep.23313

Smad3-/- Fibroblasts Are Hyperproliferative Cells With Impaired Migratory Capacity, Reduced Contractile Activity and Diminished Synthetic Function: Implications for Cardiac Repair and Remodeling

Authors
Dobaczewski, M; Gonzalez-Ouesada, C; Bujak, M; Li, N; Wang, X-F; Frangogiannis, NG
MLA Citation
Dobaczewski, M, Gonzalez-Ouesada, C, Bujak, M, Li, N, Wang, X-F, and Frangogiannis, NG. "Smad3-/- Fibroblasts Are Hyperproliferative Cells With Impaired Migratory Capacity, Reduced Contractile Activity and Diminished Synthetic Function: Implications for Cardiac Repair and Remodeling." November 3, 2009.
Source
wos-lite
Published In
Circulation
Volume
120
Issue
18
Publish Date
2009
Start Page
S792
End Page
S792

Targeting interleukin 6 signaling suppresses glioma stem cell survival and tumor growth.

Glioblastomas are the most common and most lethal primary brain tumor. Recent studies implicate an important role for a restricted population of neoplastic cells (glioma stem cells (GSCs)) in glioma maintenance and recurrence. We now demonstrate that GSCs preferentially express two interleukin 6 (IL6) receptors: IL6 receptor alpha (IL6R alpha) and glycoprotein 130 (gp130). Targeting IL6R alpha or IL6 ligand expression in GSCs with the use of short hairpin RNAs (shRNAs) significantly reduces growth and neurosphere formation capacity while increasing apoptosis. Perturbation of IL6 signaling in GSCs attenuates signal transducers and activators of transcription three (STAT3) activation, and small molecule inhibitors of STAT3 potently induce GSC apoptosis. These data indicate that STAT3 is a downstream mediator of prosurvival IL6 signals in GSCs. Targeting of IL6R alpha or IL6 expression in GSCs increases the survival of mice bearing intracranial human glioma xenografts. IL6 is clinically significant because elevated IL6 ligand and receptor expression are associated with poor glioma patient survival. The potential utility of anti-IL6 therapies is demonstrated by decreased growth of subcutaneous human GSC-derived xenografts treated with IL6 antibody. Together, our data indicate that IL6 signaling contributes to glioma malignancy through the promotion of GSC growth and survival, and that targeting IL6 may offer benefit for glioma patients.

Authors
Wang, H; Lathia, JD; Wu, Q; Wang, J; Li, Z; Heddleston, JM; Eyler, CE; Elderbroom, J; Gallagher, J; Schuschu, J; MacSwords, J; Cao, Y; McLendon, RE; Wang, X-F; Hjelmeland, AB; Rich, JN
MLA Citation
Wang, H, Lathia, JD, Wu, Q, Wang, J, Li, Z, Heddleston, JM, Eyler, CE, Elderbroom, J, Gallagher, J, Schuschu, J, MacSwords, J, Cao, Y, McLendon, RE, Wang, X-F, Hjelmeland, AB, and Rich, JN. "Targeting interleukin 6 signaling suppresses glioma stem cell survival and tumor growth." Stem Cells 27.10 (October 2009): 2393-2404.
PMID
19658188
Source
pubmed
Published In
Stem Cells
Volume
27
Issue
10
Publish Date
2009
Start Page
2393
End Page
2404
DOI
10.1002/stem.188

NDRG4 is required for cell cycle progression and survival in glioblastoma cells.

NDRG4 is a largely unstudied member of the predominantly tumor suppressive N-Myc downstream-regulated gene (NDRG) family. Unlike its family members NDRG1-3, which are ubiquitously expressed, NDRG4 is expressed almost exclusively in the heart and brain. Given this tissue-specific expression pattern and the established tumor suppressive roles of the NDRG family in regulating cellular proliferation, we investigated the cellular and biochemical functions of NDRG4 in the context of astrocytes and glioblastoma multiforme (GBM) cells. We show that, in contrast to NDRG2, NDRG4 expression is elevated in GBM and NDRG4 is required for the viability of primary astrocytes, established GBM cell lines, and both CD133(+) (cancer stem cell (CSC)-enriched) and CD133(-) primary GBM xenograft cells. While NDRG4 overexpression has no effect on cell viability, NDRG4 knockdown causes G(1) cell cycle arrest followed by apoptosis. The initial G(1) arrest is associated with a decrease in cyclin D1 expression and an increase in p27(Kip1) expression, and the subsequent apoptosis is associated with a decrease in the expression of XIAP and survivin. As a result of these effects on cell cycle progression and survival, NDRG4 knockdown decreases the tumorigenic capacity of established GBM cell lines and GBM CSC-enriched cells that have been implanted intracranially into immunocompromised mice. Collectively, these data indicate that NDRG4 is required for cell cycle progression and survival, thereby diverging in function from its tumor suppressive family member NDRG2 in astrocytes and GBM cells.

Authors
Schilling, SH; Hjelmeland, AB; Radiloff, DR; Liu, IM; Wakeman, TP; Fielhauer, JR; Foster, EH; Lathia, JD; Rich, JN; Wang, X-F; Datto, MB
MLA Citation
Schilling, SH, Hjelmeland, AB, Radiloff, DR, Liu, IM, Wakeman, TP, Fielhauer, JR, Foster, EH, Lathia, JD, Rich, JN, Wang, X-F, and Datto, MB. "NDRG4 is required for cell cycle progression and survival in glioblastoma cells." J Biol Chem 284.37 (September 11, 2009): 25160-25169.
PMID
19592488
Source
pubmed
Published In
The Journal of biological chemistry
Volume
284
Issue
37
Publish Date
2009
Start Page
25160
End Page
25169
DOI
10.1074/jbc.M109.012484

Reduced ATR or Chk1 expression leads to chromosome instability and chemosensitization of mismatch repair-deficient colorectal cancer cells.

Genomic instability in colorectal cancer is categorized into two distinct classes: chromosome instability (CIN) and microsatellite instability (MSI). MSI is the result of mutations in the mismatch repair (MMR) machinery, whereas CIN is often thought to be associated with a disruption in the APC gene. Clinical data has recently shown the presence of heterozygous mutations in ATR and Chk1 in human cancers that exhibit MSI, suggesting that those mutations may contribute to tumorigenesis. To determine whether reduced activity in the DNA damage checkpoint pathway would cooperate with MMR deficiency to induce CIN, we used siRNA strategies to partially decrease the expression of ATR or Chk1 in MMR-deficient colorectal cancer cells. The resultant cancer cells display a typical CIN phenotype, as characterized by an increase in the number of chromosomal abnormalities. Importantly, restoration of MMR proficiency completely inhibited induction of the CIN phenotype, indicating that the combination of partial checkpoint blockage and MMR deficiency is necessary to trigger CIN. Moreover, disruption of ATR and Chk1 in MMR-deficient cells enhanced the sensitivity to treatment with the commonly used colorectal chemotherapeutic compound, 5-fluorouracil. These results provide a basis for the development of a combination therapy for those cancer patients.

Authors
Jardim, MJ; Wang, Q; Furumai, R; Wakeman, T; Goodman, BK; Wang, X-F
MLA Citation
Jardim, MJ, Wang, Q, Furumai, R, Wakeman, T, Goodman, BK, and Wang, X-F. "Reduced ATR or Chk1 expression leads to chromosome instability and chemosensitization of mismatch repair-deficient colorectal cancer cells." Mol Biol Cell 20.17 (September 2009): 3801-3809.
PMID
19570909
Source
pubmed
Published In
Molecular Biology of the Cell
Volume
20
Issue
17
Publish Date
2009
Start Page
3801
End Page
3809
DOI
10.1091/mbc.E09-04-0303

PP2A-dependent dephosphorylation of replication protein A (RPA) is required for the removal of DNA breaks induced by replication stress

Authors
Feng, J; Wakeman, T; Yong, S; Kornbluth, S; Wu, X-H; Wang, X-F
MLA Citation
Feng, J, Wakeman, T, Yong, S, Kornbluth, S, Wu, X-H, and Wang, X-F. "PP2A-dependent dephosphorylation of replication protein A (RPA) is required for the removal of DNA breaks induced by replication stress." May 1, 2009.
Source
wos-lite
Published In
Cancer Research
Volume
69
Publish Date
2009

Protein phosphatase 2A-dependent dephosphorylation of replication protein A is required for the repair of DNA breaks induced by replication stress

Eukaryotic genomic integrity is safeguarded by cell cycle checkpoints and DNA repair pathways, collectively known as the DNA damage response, wherein replication protein A (RPA) is a key regulator playing multiple critical roles. The genotoxic insult-induced phosphorylation of the 32-kDa subunit of human RPA (RPA32), most notably the ATM/ATR-dependent phosphorylation at T21 and S33, acts to suppress DNA replication and recruit other checkpoint/repair proteins to the DNA lesions. It is not clear, however, how the DNA damage-responsive function of phosphorylated RPA is attenuated and how the replication-associated activity of the unphosphorylated form of RPA is restored when cells start to resume the normal cell cycle. We report here that in cells recovering from hydroxyurea (HU)-induced genotoxic stress, RPA32 is dephosphorylated by the serine/threonine protein phosphatase 2A (PP2A). Interference with PP2A catalytic activity causes persistent RPA32 phosphorylation and increased HU sensitivity. The PP2A catalytic subunit binds to RPA following DNA damage and can dephosphorylate RPA32 in vitro. Cells expressing a RPA32 persistent phosphorylation mimetic exhibit normal checkpoint activation and reenter the cell cycle normally after recovery but display a pronounced defect in the repair of DNA breaks. These data indicate that PP2A-mediated RPA32 dephosphorylation is required for the efficient DNA damage repair. Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Authors
Feng, J; Wakeman, T; Yong, S; Wu, X; Kornbluth, S; Wang, X-F
MLA Citation
Feng, J, Wakeman, T, Yong, S, Wu, X, Kornbluth, S, and Wang, X-F. "Protein phosphatase 2A-dependent dephosphorylation of replication protein A is required for the repair of DNA breaks induced by replication stress." Molecular and Cellular Biology 29.21 (2009): 5696-5709.
PMID
19704001
Source
scival
Published In
Molecular and Cellular Biology
Volume
29
Issue
21
Publish Date
2009
Start Page
5696
End Page
5709
DOI
10.1128/MCB.00191-09

Finale: The Last Minutes of Smads

TGF-β ligands induce phosphorylation of receptor-activated Smads at both the C-terminal tail and the linker region. Two papers from Massagué and colleagues (Alarcón et al., 2009; Gao et al., 2009) reveal a dual role for this linker phosphorylation, which is required for activation of Smads and for their degradation. © 2009 Elsevier Inc. All rights reserved.

Authors
Chen, Y-G; Wang, X-F
MLA Citation
Chen, Y-G, and Wang, X-F. "Finale: The Last Minutes of Smads." Cell 139.4 (2009): 658-660.
PMID
19914161
Source
scival
Published In
Cell
Volume
139
Issue
4
Publish Date
2009
Start Page
658
End Page
660
DOI
10.1016/j.cell.2009.10.038

From breast to the brain: Unraveling the puzzle of metastasis organotropism

Metastatic colonization of different target organs is a highly selective process that depends on specialized properties of tumor cells. In a recent Nature paper, Massagué and colleagues built on their earlier success in functional genomic analysis of breast cancer metastasis to bone and lung and reported the identification of breast cancer brain metastasis genes, highlighting the importance of the stromal environment in the development of organ-specific metastasis. © The Author (2009).

Authors
Hu, G; Kang, Y; Wang, X-F
MLA Citation
Hu, G, Kang, Y, and Wang, X-F. "From breast to the brain: Unraveling the puzzle of metastasis organotropism." Journal of Molecular Cell Biology 1.1 (2009): 3-5.
PMID
19633017
Source
scival
Published In
Journal of Molecular Cell Biology
Volume
1
Issue
1
Publish Date
2009
Start Page
3
End Page
5
DOI
10.1093/jmcb/mjp005

TGFβ-stimulated Smad1/5 phosphorylation requires the ALK5 L45 loop and mediates the pro-migratory TGFβ switch

During the course of breast cancer progression, normally dormant tumour-promoting effects of transforming growth factor β (TGFβ), including migration, invasion, and metastasis are unmasked. In an effort to identify mechanisms that regulate the pro-migratory TGFβ 'switch' in mammary epithelial cells in vitro, we found that TGFβ stimulates the phosphorylation of Smad1 and Smad5, which are typically associated with bone morphogenetic protein signalling. Mechanistically, this phosphorylation event requires the kinase activity and, unexpectedly, the L45 loop motif of the type I TGFβ receptor, ALK5, as evidenced by studies using short hairpin RNA-resistant ALK5 mutants in ALK5-depleted cells and in vitro kinase assays. Functionally, Smad1/5 co-depletion studies demonstrate that this phosphorylation event is essential to the initiation and promotion of TGFβ-stimulated migration. Moreover, this phosphorylation event is preferentially detected in permissive environments such as those created by tumorigenic cells or oncogene activation. Taken together, our data provide evidence that TGFβ-stimulated Smad1/5 phosphorylation, which occurs through a non-canonical mechanism that challenges the notion of selective Smad phosphorylation by ALK5, mediates the pro-migratory TGFβ switch in mammary epithelial cells. © 2009 European Molecular Biology Organization | All Rights Reserved.

Authors
Liu, IM; Schilling, SH; Knouse, KA; Choy, L; Derynck, R; Wang, X-F
MLA Citation
Liu, IM, Schilling, SH, Knouse, KA, Choy, L, Derynck, R, and Wang, X-F. "TGFβ-stimulated Smad1/5 phosphorylation requires the ALK5 L45 loop and mediates the pro-migratory TGFβ switch." EMBO Journal 28.2 (2009): 88-98.
PMID
19096363
Source
scival
Published In
EMBO Journal
Volume
28
Issue
2
Publish Date
2009
Start Page
88
End Page
98
DOI
10.1038/emboj.2008.266

A special issue on TGF-β signaling

Authors
Chen, Y-G; Wang, X-F
MLA Citation
Chen, Y-G, and Wang, X-F. "A special issue on TGF-β signaling." Cell Research 19.1 (2009): 1-2.
PMID
19125152
Source
scival
Published In
Cell Research
Volume
19
Issue
1
Publish Date
2009
Start Page
1
End Page
2
DOI
10.1038/cr.2009.3

Signaling cross-talk between TGF-β/BMP and other pathways

Transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP) signaling is involved in the vast majority of cellular processes and is fundamentally important during the entire life of all metazoans. Deregulation of TGF-β/BMP activity almost invariably leads to developmental defects and/or diseases, including cancer. The proper functioning of the TGF-β/BMP pathway depends on its constitutive and extensive communication with other signaling pathways, leading to synergistic or antagonistic effects and eventually desirable biological outcomes. The nature of such signaling cross-talk is overwhelmingly complex and highly context-dependent. Here we review the different modes of cross-talk between TGF-β/BMP and the signaling pathways of Mitogen-activated protein kinase, phosphatidylinositol-3 kinase/Akt, Wnt, Hedgehog, Notch, and the interleukin/interferon-gamma/tumor necrosis factor-alpha cytokines, with an emphasis on the underlying molecular mechanisms. © 2009 IBCB, SIBS, CAS All rights reserved.

Authors
Guo, X; Wang, X-F
MLA Citation
Guo, X, and Wang, X-F. "Signaling cross-talk between TGF-β/BMP and other pathways." Cell Research 19.1 (2009): 71-88.
PMID
19002158
Source
scival
Published In
Cell Research
Volume
19
Issue
1
Publish Date
2009
Start Page
71
End Page
88
DOI
10.1038/cr.2008.302

Ligand-dependent ubiquitination of Smad3 is regulated by casein kinase 1 gamma 2, an inhibitor of TGF-beta signaling.

Transforming growth factor-beta (TGF-beta) elicits a variety of cellular activities primarily through a signaling cascade mediated by two key transcription factors, Smad2 and Smad3. Numerous regulatory mechanisms exist to control the activity of Smad3, thereby modulating the strength and specificity of TGF-beta responses. In search for potential regulators of Smad3 through a yeast two-hybrid screen, we identified casein kinase 1 gamma 2 (CKIgamma2) as a novel Smad3-interacting protein. In mammalian cells, CKIgamma2 selectively and constitutively binds Smad3 but not Smad1, -2 or -4. Functionally, CKIgamma2 inhibits Smad3-mediated TGF-beta responses including induction of target genes and cell growth arrest, and this inhibition is dependent on CKIgamma2 kinase activity. Mechanistically, CKIgamma2 does not affect the basal levels of Smad proteins or activity of the receptors. Rather, CKIgamma2 preferentially promotes the ubiquitination and degradation of activated Smad3 through direct phosphorylation of its MH2 domain at Ser418. Importantly, mutation of Ser418 to alanine or aspartic acid causes an increase or decrease of Smad3 activity, respectively, in the presence of TGF-beta. CKIgamma2 is the first kinase known to mark activated Smad3 for destruction. Given its negative function in TGF-beta signaling and its reported overexpression in human cancers, CKIgamma2 may act as an oncoprotein during tumorigenesis.

Authors
Guo, X; Waddell, DS; Wang, W; Wang, Z; Liberati, NT; Yong, S; Liu, X; Wang, X-F
MLA Citation
Guo, X, Waddell, DS, Wang, W, Wang, Z, Liberati, NT, Yong, S, Liu, X, and Wang, X-F. "Ligand-dependent ubiquitination of Smad3 is regulated by casein kinase 1 gamma 2, an inhibitor of TGF-beta signaling." Oncogene 27.58 (December 11, 2008): 7235-7247.
PMID
18794808
Source
pubmed
Published In
Oncogene: Including Oncogene Reviews
Volume
27
Issue
58
Publish Date
2008
Start Page
7235
End Page
7247
DOI
10.1038/onc.2008.337

The Smad3 Pathway Critically Regulates Myofibroblast Proliferation And Synthetic Activity In Healing Myocardial Infarcts

Authors
Dobaczewski, M; Bujak, M; Gonzalez, C; Li, N; Wang, X-F; Frangogiannis, NG
MLA Citation
Dobaczewski, M, Bujak, M, Gonzalez, C, Li, N, Wang, X-F, and Frangogiannis, NG. "The Smad3 Pathway Critically Regulates Myofibroblast Proliferation And Synthetic Activity In Healing Myocardial Infarcts." October 28, 2008.
Source
wos-lite
Published In
Circulation
Volume
118
Issue
18
Publish Date
2008
Start Page
S293
End Page
S293

The cytoplasmic deacetylase HDAC6 is required for efficient oncogenic tumorigenesis.

Histone deacetylase inhibitors (HDACI) are promising antitumor agents. Although transcriptional deregulation is thought to be the main mechanism underlying their therapeutic effects, the exact mechanism and targets by which HDACIs achieve their antitumor effects remain poorly understood. It is not known whether any of the HDAC members support robust tumor growth. In this report, we show that HDAC6, a cytoplasmic-localized and cytoskeleton-associated deacetylase, is required for efficient oncogenic transformation and tumor formation. We found that HDAC6 expression is induced upon oncogenic Ras transformation. Fibroblasts deficient in HDAC6 are more resistant to both oncogenic Ras and ErbB2-dependent transformation, indicating a critical role for HDAC6 in oncogene-induced transformation. Supporting this hypothesis, inactivation of HDAC6 in several cancer cell lines reduces anchorage-independent growth and the ability to form tumors in mice. The loss of anchorage-independent growth is associated with increased anoikis and defects in AKT and extracellular signal-regulated kinase activation upon loss of adhesion. Lastly, HDAC6-null mice are more resistant to chemical carcinogen-induced skin tumors. Our results provide the first experimental evidence that a specific HDAC member is required for efficient oncogenic transformation and indicate that HDAC6 is an important component underlying the antitumor effects of HDACIs.

Authors
Lee, Y-S; Lim, K-H; Guo, X; Kawaguchi, Y; Gao, Y; Barrientos, T; Ordentlich, P; Wang, X-F; Counter, CM; Yao, T-P
MLA Citation
Lee, Y-S, Lim, K-H, Guo, X, Kawaguchi, Y, Gao, Y, Barrientos, T, Ordentlich, P, Wang, X-F, Counter, CM, and Yao, T-P. "The cytoplasmic deacetylase HDAC6 is required for efficient oncogenic tumorigenesis." Cancer Res 68.18 (September 15, 2008): 7561-7569.
PMID
18794144
Source
pubmed
Published In
Cancer Research
Volume
68
Issue
18
Publish Date
2008
Start Page
7561
End Page
7569
DOI
10.1158/0008-5472.CAN-08-0188

The cytoplasmic deacetylase HDAC6 is required for efficient oncogenic tumorigenesis

Authors
Lee, Y-S; Lim, K-H; Guo, X; Kawaguchi, Y; Gao, Y; Barrientos, T; Ordentlich, P; Wang, X-F; Counter, CM; Yao, T-P
MLA Citation
Lee, Y-S, Lim, K-H, Guo, X, Kawaguchi, Y, Gao, Y, Barrientos, T, Ordentlich, P, Wang, X-F, Counter, CM, and Yao, T-P. "The cytoplasmic deacetylase HDAC6 is required for efficient oncogenic tumorigenesis." CANCER RESEARCH 68.18 (September 15, 2008): 7561-7569.
Source
wos-lite
Published In
Cancer Research
Volume
68
Issue
18
Publish Date
2008
Start Page
7561
End Page
7569
DOI
10.1159/0008-5472.CAN-08-0188

Aven-dependent activation of ATM following DNA damage.

BACKGROUND: In response to DNA damage, cells undergo either cell-cycle arrest or apoptosis, depending on the extent of damage and the cell's capacity for DNA repair. Cell-cycle arrest induced by double-stranded DNA breaks depends on activation of the ataxia-telangiectasia (ATM) protein kinase, which phosphorylates cell-cycle effectors such as Chk2 and p53 to inhibit cell-cycle progression. ATM is recruited to double-stranded DNA breaks by a complex of sensor proteins, including Mre11/Rad50/Nbs1, resulting in autophosphorylation, monomerization, and activation of ATM kinase. RESULTS: In characterizing Aven protein, a previously reported apoptotic inhibitor, we have found that Aven can function as an ATM activator to inhibit G2/M progression. Aven bound to ATM and Aven overexpressed in cycling Xenopus egg extracts prevented mitotic entry and induced phosphorylation of ATM and its substrates. Immunodepletion of endogenous Aven allowed mitotic entry even in the presence of damaged DNA, and RNAi-mediated knockdown of Aven in human cells prevented autophosphorylation of ATM at an activating site (S1981) in response to DNA damage. Interestingly, Aven is also a substrate of the ATM kinase. Mutation of ATM-mediated phosphorylation sites on Aven reduced its ability to activate ATM, suggesting that Aven activation of ATM after DNA damage is enhanced by ATM-mediated Aven phosphorylation. CONCLUSIONS: These results identify Aven as a new ATM activator and describe a positive feedback loop operating between Aven and ATM. In aggregate, these findings place Aven, a known apoptotic inhibitor, as a critical transducer of the DNA-damage signal.

Authors
Guo, JY; Yamada, A; Kajino, T; Wu, JQ; Tang, W; Freel, CD; Feng, J; Chau, BN; Wang, MZ; Margolis, SS; Yoo, HY; Wang, X-F; Dunphy, WG; Irusta, PM; Hardwick, JM; Kornbluth, S
MLA Citation
Guo, JY, Yamada, A, Kajino, T, Wu, JQ, Tang, W, Freel, CD, Feng, J, Chau, BN, Wang, MZ, Margolis, SS, Yoo, HY, Wang, X-F, Dunphy, WG, Irusta, PM, Hardwick, JM, and Kornbluth, S. "Aven-dependent activation of ATM following DNA damage." Curr Biol 18.13 (July 8, 2008): 933-942.
PMID
18571408
Source
pubmed
Published In
Current Biology
Volume
18
Issue
13
Publish Date
2008
Start Page
933
End Page
942
DOI
10.1016/j.cub.2008.05.045

Extracellular matrix protein betaig-h3/TGFBI promotes metastasis of colon cancer by enhancing cell extravasation.

Metastasis, the major cause of cancer death, is a multistep process that requires interactions between cancer cells and stromal cells and between cancer cells and extracellular matrix. Molecular alterations of the extracellular matrix in the tumor microenvironment have a considerable impact on the metastatic process during tumorigenesis. Here we report that elevated expression of betaig-h3/TGFBI (transforming growth factor, beta-induced), an extracellular matrix protein secreted by colon cancer cells, is associated with high-grade human colon cancers. Ectopic expression of the betaig-h3 protein enhanced the aggressiveness and altered the metastatic properties of colon cancer cells in vivo. Inhibition of betaig-h3 expression dramatically reduced metastasis. Mechanistically, betaig-h3 appears to promote extravasation, a critical step in the metastatic dissemination of cancer cells, by inducing the dissociation of VE-cadherin junctions between endothelial cells via activation of the integrin alphavbeta5-Src signaling pathway. Thus, cancers associated with overexpression of betaig-h3 may have an increased metastatic potential, leading to poor prognosis in cancer patients.

Authors
Ma, C; Rong, Y; Radiloff, DR; Datto, MB; Centeno, B; Bao, S; Cheng, AWM; Lin, F; Jiang, S; Yeatman, TJ; Wang, X-F
MLA Citation
Ma, C, Rong, Y, Radiloff, DR, Datto, MB, Centeno, B, Bao, S, Cheng, AWM, Lin, F, Jiang, S, Yeatman, TJ, and Wang, X-F. "Extracellular matrix protein betaig-h3/TGFBI promotes metastasis of colon cancer by enhancing cell extravasation." Genes Dev 22.3 (February 1, 2008): 308-321.
PMID
18245446
Source
pubmed
Published In
Genes & development
Volume
22
Issue
3
Publish Date
2008
Start Page
308
End Page
321
DOI
10.1101/gad.1632008

Axin and GSK3-beta control Smad3 protein stability and modulate TGF-beta signaling

Authors
Guo, X; Ramirez, A; Waddell, DS; Li, Z; Liu, X; Wang, X-F
MLA Citation
Guo, X, Ramirez, A, Waddell, DS, Li, Z, Liu, X, and Wang, X-F. "Axin and GSK3-beta control Smad3 protein stability and modulate TGF-beta signaling." GENES & DEVELOPMENT 22.1 (January 1, 2008): 106-120.
Source
wos-lite
Published In
Genes & development
Volume
22
Issue
1
Publish Date
2008
Start Page
106
End Page
120
DOI
10.1101/gal.1590908

Axin and GSK3- control Smad3 protein stability and modulate TGF- signaling.

The broad range of biological responses elicited by transforming growth factor-beta (TGF-beta) in various types of tissues and cells is mainly determined by the expression level and activity of the effector proteins Smad2 and Smad3. It is not fully understood how the baseline properties of Smad3 are regulated, although this molecule is in complex with many other proteins at the steady state. Here we show that nonactivated Smad3, but not Smad2, undergoes proteasome-dependent degradation due to the concerted action of the scaffolding protein Axin and its associated kinase, glycogen synthase kinase 3-beta (GSK3-beta). Smad3 physically interacts with Axin and GSK3-beta only in the absence of TGF-beta. Reduction in the expression or activity of Axin/GSK3-beta leads to increased Smad3 stability and transcriptional activity without affecting TGF-beta receptors or Smad2, whereas overexpression of these proteins promotes Smad3 basal degradation and desensitizes cells to TGF-beta. Mechanistically, Axin facilitates GSK3-beta-mediated phosphorylation of Smad3 at Thr66, which triggers Smad3 ubiquitination and degradation. Thr66 mutants of Smad3 show altered protein stability and hence transcriptional activity. These results indicate that the steady-state stability of Smad3 is an important determinant of cellular sensitivity to TGF-beta, and suggest a new function of the Axin/GSK3-beta complex in modulating critical TGF-beta/Smad3-regulated processes during development and tumor progression.

Authors
Guo, X; Ramirez, A; Waddell, DS; Li, Z; Liu, X; Wang, X-F
MLA Citation
Guo, X, Ramirez, A, Waddell, DS, Li, Z, Liu, X, and Wang, X-F. "Axin and GSK3- control Smad3 protein stability and modulate TGF- signaling." Genes Dev 22.1 (January 1, 2008): 106-120.
PMID
18172167
Source
pubmed
Published In
Genes & development
Volume
22
Issue
1
Publish Date
2008
Start Page
106
End Page
120
DOI
10.1101/gad.1590908

In vitro assays for the extracellular matrix protein-regulated extravasation process

Authors
Ma, C; Wang, X-F
MLA Citation
Ma, C, and Wang, X-F. "In vitro assays for the extracellular matrix protein-regulated extravasation process." Cold Spring Harbor Protocols 3.8 (2008).
PMID
21356892
Source
scival
Published In
Cold Spring Harbor Protocols
Volume
3
Issue
8
Publish Date
2008
DOI
10.1101/pdb.prot5034

Smad3 signaling critically regulates infarct healing

Authors
Bujak, MJ; Ren, G; Chatila, KF; Dobaczewski, M; Reddy, A; Taffet, G; Wang, X-F; Frangogiannis, NG
MLA Citation
Bujak, MJ, Ren, G, Chatila, KF, Dobaczewski, M, Reddy, A, Taffet, G, Wang, X-F, and Frangogiannis, NG. "Smad3 signaling critically regulates infarct healing." April 2007.
Source
wos-lite
Published In
The FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Volume
21
Issue
5
Publish Date
2007
Start Page
A11
End Page
A11

Disruption of the Smad3 signaling pathway attenuates post-infarction remodeling

Authors
Buiak, MJ; Ren, G; Chatila, K; Dobaczewski, M; Reddy, A; Taffet, G; Wang, X-F; Frangogiannis, NG
MLA Citation
Buiak, MJ, Ren, G, Chatila, K, Dobaczewski, M, Reddy, A, Taffet, G, Wang, X-F, and Frangogiannis, NG. "Disruption of the Smad3 signaling pathway attenuates post-infarction remodeling." March 6, 2007.
Source
wos-lite
Published In
JACC - Journal of the American College of Cardiology
Volume
49
Issue
9
Publish Date
2007
Start Page
210A
End Page
210A

Essential role of Smad3 in infarct healing and in the pathogenesis of cardiac remodeling

BACKGROUND - Postinfarction cardiac repair is regulated through timely activation and repression of inflammatory pathways, followed by transition to fibrous tissue deposition and formation of a scar. The transforming growth factor-β/Smad3 pathway is activated in healing infarcts and may regulate cellular events critical for the inflammatory and the fibrotic responses. METHODS AND RESULTS - We examined the effects of Smad3 gene disruption on infarct healing and the pathogenesis of cardiac remodeling. In the absence of injury, Smad3-null hearts had comparable function to and similar morphology as wild-type hearts. Smad3-null animals had suppressed peak chemokine expression and decreased neutrophil recruitment in the infarcted myocardium but showed timely repression of inflammatory gene synthesis and resolution of the inflammatory infiltrate. Although myofibroblast density was higher in Smad3-null infarcts, interstitial deposition of collagen and tenascin-C in the remodeling myocardium was markedly reduced. Compared with wild-type animals, Smad3 mice exhibited decreased dilative remodeling and attenuated diastolic dysfunction; however, infarct size was comparable between groups. Transforming growth factor-β-mediated induction of procollagen type III and tenascin-C in isolated cardiac fibroblasts was dependent on Smad3, which suggests that decreased fibrotic remodeling in infarcted Smad3-null hearts may be due to abrogation of the profibrotic transforming growth factor-β responses. CONCLUSIONS - Smad3 loss does not alter the time course of resolution of inflammation in healing infarcts, but it prevents interstitial fibrosis in the noninfarcted myocardium and attenuates cardiac remodeling. Thus, the Smad3 cascade may be a promising therapeutic target for the treatment of myocardial infarction. © 2007 American Heart Association, Inc.

Authors
Bujak, M; Ren, G; Kweon, HJ; Dobaczewski, M; Reddy, A; Taffet, G; Wang, X-F; Frangogiannis, NG
MLA Citation
Bujak, M, Ren, G, Kweon, HJ, Dobaczewski, M, Reddy, A, Taffet, G, Wang, X-F, and Frangogiannis, NG. "Essential role of Smad3 in infarct healing and in the pathogenesis of cardiac remodeling." Circulation 116.19 (2007): 2127-2138.
PMID
17967775
Source
scival
Published In
Circulation
Volume
116
Issue
19
Publish Date
2007
Start Page
2127
End Page
2138
DOI
10.1161/CIRCULATIONAHA.107.704197

Up-regulation of tumor susceptibility gene 101 conveys poor prognosis through suppression of p21 expression in ovarian cancer

Purpose: The function of tumor susceptibility gene 101 (TSG101) in ovarian carcinogenesis is largely unexplored. The aim of this study is to investigate the role of TSG101 in human ovarian cancer development, to examine the expression levels of TSG101 in ovarian carcinomas, and to correlate the results with clinicopathologic variables and survival. Experimental Design: Human ovarian cancer tissue arrays that contain duplicates of 422 cases of primary ovarian carcinoma were used to probe the expression levels of TSG101 and p21 in epithelial ovarian cancer. In vitro studies in ovarian cancer cells using TSG101-specific small interfering RNA (siRNA) were done to further elucidate the mechanism of TSG101-mediated p21 regulation. Results: We show that TSG101 is increasingly overexpressed in borderline tumors and low-grade and high-grade carcinomas. Patients with low expression of TSG101 survive longer than those with high expression. Suppressing TSG101 by siRNA in ovarian cancer cells led to growth inhibition, cell cycle arrest, and apoptosis with concurrent increases in p21 mRNA and protein. Consistent with this negative association between TSG101 and p21, expression levels of these two markers are inversely correlated in ovarian cancer. Conclusions: TSG101 negatively regulates p21 levels, and up-regulation of TSG101 is associated with poor prognosis in ovarian cancer. © 2007 American Association for Cancer Research.

Authors
Young, TW; Rosen, DG; Mei, FC; Li, N; Liu, J; Wang, X-F; Cheng, X
MLA Citation
Young, TW, Rosen, DG, Mei, FC, Li, N, Liu, J, Wang, X-F, and Cheng, X. "Up-regulation of tumor susceptibility gene 101 conveys poor prognosis through suppression of p21 expression in ovarian cancer." Clinical Cancer Research 13.13 (2007): 3848-3854.
PMID
17606716
Source
scival
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
13
Issue
13
Publish Date
2007
Start Page
3848
End Page
3854
DOI
10.1158/1078-0432.CCR-07-0337

Role for the PP2A/B56delta phosphatase in regulating 14-3-3 release from Cdc25 to control mitosis.

DNA-responsive checkpoints prevent cell-cycle progression following DNA damage or replication inhibition. The mitotic activator Cdc25 is suppressed by checkpoints through inhibitory phosphorylation at Ser287 (Xenopus numbering) and docking of 14-3-3. Ser287 phosphorylation is a major locus of G2/M checkpoint control, although several checkpoint-independent kinases can phosphorylate this site. We reported previously that mitotic entry requires 14-3-3 removal and Ser287 dephosphorylation. We show here that DNA-responsive checkpoints also activate PP2A/B56delta phosphatase complexes to dephosphorylate Cdc25 at a site distinct from Ser287 (T138), the phosphorylation of which is required for 14-3-3 release. However, phosphorylation of T138 is not sufficient for 14-3-3 release from Cdc25. Our data suggest that creation of a 14-3-3 "sink," consisting of phosphorylated 14-3-3 binding intermediate filament proteins, including keratins, coupled with reduced Cdc25-14-3-3 affinity, contribute to Cdc25 activation. These observations identify PP2A/B56delta as a central checkpoint effector and suggest a mechanism for controlling 14-3-3 interactions to promote mitosis.

Authors
Margolis, SS; Perry, JA; Forester, CM; Nutt, LK; Guo, Y; Jardim, MJ; Thomenius, MJ; Freel, CD; Darbandi, R; Ahn, J-H; Arroyo, JD; Wang, X-F; Shenolikar, S; Nairn, AC; Dunphy, WG; Hahn, WC; Virshup, DM; Kornbluth, S
MLA Citation
Margolis, SS, Perry, JA, Forester, CM, Nutt, LK, Guo, Y, Jardim, MJ, Thomenius, MJ, Freel, CD, Darbandi, R, Ahn, J-H, Arroyo, JD, Wang, X-F, Shenolikar, S, Nairn, AC, Dunphy, WG, Hahn, WC, Virshup, DM, and Kornbluth, S. "Role for the PP2A/B56delta phosphatase in regulating 14-3-3 release from Cdc25 to control mitosis." Cell 127.4 (November 17, 2006): 759-773.
PMID
17110335
Source
pubmed
Published In
Cell
Volume
127
Issue
4
Publish Date
2006
Start Page
759
End Page
773
DOI
10.1016/j.cell.2006.10.035

A phosphatase controls the fate of receptor-regulated Smads.

In this issue of Cell, Lin et al. (2006) answer one of the long-standing questions in the TGFbeta field by identifying a phosphatase, PPM1A, that directly dephosphorylates Smad2 and Smad3 to limit their activation.

Authors
Schilling, SH; Datto, MB; Wang, X-F
MLA Citation
Schilling, SH, Datto, MB, and Wang, X-F. "A phosphatase controls the fate of receptor-regulated Smads." Cell 125.5 (June 2, 2006): 838-840. (Review)
PMID
16751094
Source
pubmed
Published In
Cell
Volume
125
Issue
5
Publish Date
2006
Start Page
838
End Page
840
DOI
10.1016/j.cell.2006.05.015

Smad3-dependent nuclear translocation of beta-catenin is required for TGF-beta1-induced proliferation of bone marrow-derived adult human mesenchymal stem cells.

Adult mesenchymal stem cells (MSCs) derived from bone marrow contribute to the regeneration of multiple types of mesenchymal tissues. Here we describe the functional role of a novel form of cross-talk between the transforming growth factor beta1 (TGF-beta1) and Wnt signaling pathways in regulating the activities of human MSCs. We show that TGF-beta1 induces rapid nuclear translocation of beta-catenin in MSCs in a Smad3-dependent manner. Functionally, this pathway is required for the stimulation of MSC proliferation and the inhibition of MSC osteogenic differentiation by TGF-beta1, likely through the regulation of specific downstream target genes. These results provide evidence for a new mode of cooperation between the TGF-beta and Wnt signaling pathways in this specific cellular context and suggest a potentially important role for this distinct signaling pathway in the control of self-renewal and differentiation of a specific type of MSCs.

Authors
Jian, H; Shen, X; Liu, I; Semenov, M; He, X; Wang, X-F
MLA Citation
Jian, H, Shen, X, Liu, I, Semenov, M, He, X, and Wang, X-F. "Smad3-dependent nuclear translocation of beta-catenin is required for TGF-beta1-induced proliferation of bone marrow-derived adult human mesenchymal stem cells." Genes Dev 20.6 (March 15, 2006): 666-674.
PMID
16543220
Source
pubmed
Published In
Genes & development
Volume
20
Issue
6
Publish Date
2006
Start Page
666
End Page
674
DOI
10.1101/gad.1388806

Loss of phosphatase and tensin homologue increases transforming growth factor beta-mediated invasion with enhanced SMAD3 transcriptional activity.

In normal epithelial tissues, the multifunctional cytokine transforming growth factor-beta (TGF-beta) acts as a tumor suppressor through growth inhibition and induction of differentiation whereas in advanced cancers, TGF-beta promotes tumor progression through induction of tumor invasion, neoangiogenesis, and immunosuppression. The molecular mechanisms through which TGF-beta shifts from a tumor suppressor to a tumor enhancer are poorly understood. We now show a role for the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in repressing the protumorigenic effects of TGF-beta. The TGF-beta effector SMAD3 inducibly interacts with PTEN on TGF-beta treatment under endogenous conditions. RNA interference (RNAi) suppression of PTEN expression enhances SMAD3 transcriptional activity and TGF-beta-mediated induction of SMAD3 target genes whereas reconstitution of PTEN in a null cancer cell line represses the expression of TGF-beta-regulated target genes. Targeting PTEN expression through RNAi in a PTEN wild-type cell line increases TGF-beta-mediated invasion but does not affect TGF-beta-mediated growth inhibition. Reconstitution of PTEN expression in a PTEN-null cell line blocks TGF-beta-induced invasion but does not modulate TGF-beta-mediated growth regulation. These effects are distinct from Akt and Forkhead family members that also interact with SMAD3 to regulate apoptosis or proliferation, respectively. Pharmacologic inhibitors targeting TGF-beta receptors and phosphatidylinositol 3-kinase signaling downstream from PTEN cooperate to block TGF-beta-mediated invasion. Thus, the loss of PTEN expression in human cancers may contribute to a role for TGF-beta as a tumor enhancer with specific effects on cellular motility and invasion.

Authors
Hjelmeland, AB; Hjelmeland, MD; Shi, Q; Hart, JL; Bigner, DD; Wang, X-F; Kontos, CD; Rich, JN
MLA Citation
Hjelmeland, AB, Hjelmeland, MD, Shi, Q, Hart, JL, Bigner, DD, Wang, X-F, Kontos, CD, and Rich, JN. "Loss of phosphatase and tensin homologue increases transforming growth factor beta-mediated invasion with enhanced SMAD3 transcriptional activity." Cancer Res 65.24 (December 15, 2005): 11276-11281.
PMID
16357132
Source
pubmed
Published In
Cancer Research
Volume
65
Issue
24
Publish Date
2005
Start Page
11276
End Page
11281
DOI
10.1158/0008-5472.CAN-05-3016

Stable RNA interference-mediated suppression of cyclophilin A diminishes non-small-cell lung tumor growth in vivo.

Cyclophilin A (CypA) was recently reported to be overexpressed in non-small-cell lung cancer, and represents a potentially novel therapeutic target. To determine the role of CypA in oncogenesis, stable RNA interference (RNAi)-mediated knockdown of CypA was established in two non-small-cell lung cancer cell lines (ADLC-5M2 and LC-103H), and these cells were grown as xenografts in severe combined immunodeficient mice. Tumor cell proliferation, apoptosis, and angiogenesis were measured by Ki67, terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling, and CD31 immunohistochemistry, respectively. Tumor glucose metabolism was assessed by fluorodeoxyglucose positron emission tomography imaging. Knockdown of CypA correlated in vivo with slower growth, less fluorodeoxyglucose uptake, decreased proliferation, and a greater degree of apoptosis in the tumors. These results establish the relevance of CypA to tumor growth in vivo, specifically to proliferation and apoptosis. Elucidation of the precise role of CypA in these pathways may lead to new targeted therapies for lung cancer.

Authors
Howard, BA; Furumai, R; Campa, MJ; Rabbani, ZN; Vujaskovic, Z; Wang, XF; Patz, EF
MLA Citation
Howard, BA, Furumai, R, Campa, MJ, Rabbani, ZN, Vujaskovic, Z, Wang, XF, and Patz, EF. "Stable RNA interference-mediated suppression of cyclophilin A diminishes non-small-cell lung tumor growth in vivo." Cancer research 65.19 (October 2005): 8853-8860. (Academic Article)
PMID
16204056
Source
manual
Published In
Cancer Research
Volume
65
Issue
19
Publish Date
2005
Start Page
8853
End Page
8860

Ubiquitin-mediated degradation a mechanism for fine-tuning TGF-beta signaling.

Effects of the cytokine TGF-beta can be dampened by E3 ubiquitin ligases that target specific Smads, the TGF-beta signal transducers, for proteolytic destruction. Two papers in this issue of Cell highlight the importance of this mechanism in regulating the in vivo effects of TGF-beta. The first paper identifies and characterizes a novel Smad4 ubiquitin ligase, and the second paper redefines the role of a previously identified Smad1 ubiquitin ligase, Smurf-1 (Dupont et al., 2005; Yamashita et al., 2005).

Authors
Datto, M; Wang, X-F
MLA Citation
Datto, M, and Wang, X-F. "Ubiquitin-mediated degradation a mechanism for fine-tuning TGF-beta signaling." Cell 121.1 (April 8, 2005): 2-4.
PMID
15820671
Source
pubmed
Published In
Cell
Volume
121
Issue
1
Publish Date
2005
Start Page
2
End Page
4
DOI
10.1016/j.cell.2005.03.017

Combination therapy of inhibitors of epidermal growth factor receptor/vascular endothelial growth factor receptor 2 (AEE788) and the mammalian target of rapamycin (RAD001) offers improved glioblastoma tumor growth inhibition.

Malignant gliomas are highly lethal tumors that display striking genetic heterogeneity. Novel therapies that inhibit a single molecular target may slow tumor progression, but tumors are likely not dependent on a signal transduction pathway. Rather, malignant gliomas exhibit sustained mitogenesis and cell growth mediated in part through the effects of receptor tyrosine kinases and the mammalian target of rapamycin (mTOR). AEE788 is a novel orally active tyrosine kinase inhibitor that decreases the kinase activity associated with the epidermal growth factor receptor and, at higher concentrations, the vascular endothelial growth factor receptor 2 (kinase domain region). RAD001 (everolimus) is an orally available mTOR inhibitor structurally related to rapamycin. We hypothesized that combined inhibition of upstream epidermal growth factor receptor and kinase domain region receptors with AEE788 and inhibition of the downstream mTOR pathway with RAD001 would result in increased efficacy against gliomas compared with single-agent therapy. In vitro experiments showed that the combination of AEE788 and RAD001 resulted in increased rates of cell cycle arrest and apoptosis and reduced proliferation more than either agent alone. Combined AEE788 and RAD001 given orally to athymic mice bearing established human malignant glioma tumor xenografts resulted in greater tumor growth inhibition and greater increases in median survival than monotherapy. These studies suggest that simultaneous inhibition of growth factor receptor and mTOR pathways offer increased benefit in glioma therapy.

Authors
Goudar, RK; Shi, Q; Hjelmeland, MD; Keir, ST; McLendon, RE; Wikstrand, CJ; Reese, ED; Conrad, CA; Traxler, P; Lane, HA; Reardon, DA; Cavenee, WK; Wang, X-F; Bigner, DD; Friedman, HS; Rich, JN
MLA Citation
Goudar, RK, Shi, Q, Hjelmeland, MD, Keir, ST, McLendon, RE, Wikstrand, CJ, Reese, ED, Conrad, CA, Traxler, P, Lane, HA, Reardon, DA, Cavenee, WK, Wang, X-F, Bigner, DD, Friedman, HS, and Rich, JN. "Combination therapy of inhibitors of epidermal growth factor receptor/vascular endothelial growth factor receptor 2 (AEE788) and the mammalian target of rapamycin (RAD001) offers improved glioblastoma tumor growth inhibition." Mol Cancer Ther 4.1 (January 2005): 101-112.
PMID
15657358
Source
pubmed
Published In
Molecular cancer therapeutics
Volume
4
Issue
1
Publish Date
2005
Start Page
101
End Page
112

Protein phosphatase 5 is required for ATR-mediated checkpoint activation

In response to DNA damage or replication stress, the protein kinase ATR is activated and subsequently transduces genotoxic signals to cell cycle control and DNA repair machinery through phosphorylation of a number of downstream substrates. Very little is known about the molecular mechanism by which ATR is activated in response to genotoxic insults. In this report, we demonstrate that protein phosphatase 5 (PP5) is required for the ATR-mediated checkpoint activation. PP5 forms a complex with ATR in a genotoxic stress-inducible manner. Interference with the expression or the activity of PP5 leads to impairment of the ATR-mediated phosphorylation of hRad17 and Chk1 after UV or hydroxyurea treatment. Similar results are obtained in ATM-deficient cells, suggesting that the observed defect in checkpoint signaling is the consequence of impaired functional interaction between ATR and PP5. In cells exposed to UV irradiation, PP5 is required to elicit an appropriate S-phase checkpoint response. In addition, loss of PP5 leads to premature mitosis after hydroxyurea treatment. Interestingly, reduced PP5 activity exerts differential effects on the formation of intranuclear foci by ATR and replication protein A, implicating a functional role tor PP5 in a specific stage of the checkpoint signaling pathway. Taken together, our results suggest that PP5 plays a critical role in the ATR-mediated checkpoint activation. Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Authors
Zhang, J; Bao, S; Furumai, R; Kucera, KS; Ali, A; Dean, NM; Wang, X-F
MLA Citation
Zhang, J, Bao, S, Furumai, R, Kucera, KS, Ali, A, Dean, NM, and Wang, X-F. "Protein phosphatase 5 is required for ATR-mediated checkpoint activation." Molecular and Cellular Biology 25.22 (2005): 9910-9919.
PMID
16260606
Source
scival
Published In
Molecular and Cellular Biology
Volume
25
Issue
22
Publish Date
2005
Start Page
9910
End Page
9919
DOI
10.1128/MCB.25.22.9910-9919.2005

TLR agonists regulate PDGF-B production and cell proliferation through TGF-β/type I IFN crosstalk

Transforming growth factor-β (TGF-β) and type I interferon (IFN) autocrine/paracrine loops are recognized as key mediators of signaling cascades that control a variety of cellular functions. Here, we describe a novel mechanism by which Toll-like receptor (TLR) agonists utilize these two autocrine/paracrine loops to differentially regulate the induction of PDGF-B, a growth factor implicated in a number of diseases ranging from tumor metastasis to glomerulonephritis. We demonstrate that CpG-specific induction of PDGF-B requires activation of Smads through TGFβ1 autocrine/paracrine signaling. In contrast, polyinosinic:polycytidylic acid strongly represses CpG's as well as its own intrinsic ability to induce PDGF-B mRNA through type I IFN-mediated induction of Smad7, a negative regulator of Smad3/4. Furthermore, we have shown that this crosstalk mechanism translates into similar regulation of mesangial cell proliferation. Thus, our results demonstrate the importance of crosstalk between TGF-β and type I IFNs in determining the specificity of TLR-mediated gene induction. ©2005 European Molecular Biology Organization.

Authors
Chow, EK; O'Connell, RM; Schilling, S; Wang, X-F; Fu, X-Y; Cheng, G
MLA Citation
Chow, EK, O'Connell, RM, Schilling, S, Wang, X-F, Fu, X-Y, and Cheng, G. "TLR agonists regulate PDGF-B production and cell proliferation through TGF-β/type I IFN crosstalk." EMBO Journal 24.23 (2005): 4071-4081.
PMID
16308570
Source
scival
Published In
EMBO Journal
Volume
24
Issue
23
Publish Date
2005
Start Page
4071
End Page
4081
DOI
10.1038/sj.emboj.7600867

Loss of Smad3-mediated negative regulation of Runx2 activity leads to an alteration in cell fate determination

Runx2 is required for osteoblast differentiation but is expressed in certain nonosteoblastic cells without activating the differentiation process, suggesting that its activity is suppressed through a lineage-specific mechanism. Here we report that primary mouse dermal fibroblasts lacking Smad3 can acquire an osteoblast-like phenotype, including activation of Runx2 activity, expression of osteoblast-specific genes, and calcium deposition. We further show that negative regulation of Runx2 activity by Smad3 in dermal fibroblasts is likely mediated by controlling the expression of Msx2, an antagonist of Runx2 in this cellular context. These data support the presence of a novel mechanism for controlling cell fate determination of mesenchymal lineages by preventing differentiation toward the osteoblastic lineage via negative regulation of Runx2 activity. Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Authors
Hjelmeland, AB; Schilling, SH; Guo, X; Quarles, D; Wang, X-F
MLA Citation
Hjelmeland, AB, Schilling, SH, Guo, X, Quarles, D, and Wang, X-F. "Loss of Smad3-mediated negative regulation of Runx2 activity leads to an alteration in cell fate determination." Molecular and Cellular Biology 25.21 (2005): 9460-9468.
PMID
16227596
Source
scival
Published In
Molecular and Cellular Biology
Volume
25
Issue
21
Publish Date
2005
Start Page
9460
End Page
9468
DOI
10.1128/MCB.25.21.9460-9468.2005

Human Rad9 is required for the activation of S-phase checkpoint and the maintenance of chromosomal stability

In response to DNA damage or replication block, cells activate a battery of checkpoint signaling cascades to control cell cycle progression and elicit DNA repair in order to maintain genomic stability and integrity. Identified as a homolog of its fission yeast counterpart, human Rad9 was proposed to form a Rad9-Hus1-Rad1 protein complex to mediate checkpoint signals. However, the precise function of Rad9 in the process of checkpoint activation is not fully understood. Using the RNA interference technique, we investigated the role of Rad9 in the genotoxic stress-induced activation of S-phase checkpoint and the maintenance of chromosomal stability. We found that Rad9 knockdown reduced the phosphorylation of Rad17, Chk1 and Smc1 in response to DNA replication block and certain types of DNA damage. Immunofluorescence studies showed that the removal of Rad9 disrupted the foci formation of phosphorylated Chk1, but not ATR. Moreover, Rad9 knockdown resulted in radioresistant DNA synthesis and reduced cell viability under replication stress. Finally, removal of Rad9 by RNAi led to increased accumulation of spontaneous chromosomal aberrations. Taken together, these results suggest a critical and specific role of Rad9 in the activation of S-phase checkpoint and the maintenance of chromosome stability. © Blackwell Publishing Limited.

Authors
Dang, T; Bao, S; Wang, X-F
MLA Citation
Dang, T, Bao, S, and Wang, X-F. "Human Rad9 is required for the activation of S-phase checkpoint and the maintenance of chromosomal stability." Genes to Cells 10.4 (2005): 287-295.
PMID
15773892
Source
scival
Published In
Genes to Cells
Volume
10
Issue
4
Publish Date
2005
Start Page
287
End Page
295
DOI
10.1111/j.1365-2443.2005.00840.x

Abnormal mouse lung alveolarization caused by Smad3 deficiency is a developmental antecedent of centrilobular emphysema

Transforming growth factor-β (TGF-β) signaling plays an important regulatory role during lung development and remodeling. Smad3 is a major downstream signal transducer in the TGF-β pathway from the cell membrane to the nucleus. In Smad3 null mutant mice, we have observed retarded lung alveolarization from postnatal day 7 to day 28, and subsequently centrilobular emphysema starting from day 28, as determined by morphometric analysis. In addition to the morphological changes, peripheral lung cell proliferation in Smad3 knockout mice was reduced compared with the wild-type control between postnatal days 7 and 28. Expression of tropoelastin at the mRNA level was also dramatically decreased in Smad3 knockout lungs from postnatal day 28 through adulthood. Furthermore, increased matrix metalloproteinase-9 protein expression and activity were detected in the Smad3 knockout mouse lung tissue and the bronchoalveolar lavage fluid at postnatal day 28 when the centrilobular emphysema pathology was just beginning to appear. Therefore, these results indicate that Smad3 not only has a positive regulatory impact on neonatal lung alveolarization but also potentially plays a protective role against the occurrence of centrilobular emphysema later on in life. Copyright © 2005 the American Physiological Society.

Authors
Chen, H; Sun, J; Buckley, S; Chen, C; Warburton, D; Wang, X-F; Shi, W
MLA Citation
Chen, H, Sun, J, Buckley, S, Chen, C, Warburton, D, Wang, X-F, and Shi, W. "Abnormal mouse lung alveolarization caused by Smad3 deficiency is a developmental antecedent of centrilobular emphysema." American Journal of Physiology - Lung Cellular and Molecular Physiology 288.4 32-4 (2005): L683-L691.
PMID
15591413
Source
scival
Published In
American Journal of Physiology - Lung Cellular and Molecular Physiology
Volume
288
Issue
4 32-4
Publish Date
2005
Start Page
L683
End Page
L691
DOI
10.1152/ajplung.00298.2004

Secreted protein acidic, rich in cysteine (SPARC), mediates cellular survival of gliomas through AKT activation.

Secreted protein acidic, rich in cysteine (SPARC), is an extracellular matrix protein expressed in many advanced cancers, including malignant gliomas. We and others have previously shown that human glioma cell lines engineered to overexpress SPARC adopt an invasive phenotype. We now show that SPARC expression increases cell survival under stress initiated by serum withdrawal through a decrease in apoptosis. Phosphatidylinositol 3-OH kinase/AKT is a potent pro-survival pathway that contributes to the malignancy of gliomas. Cells expressing SPARC display increased AKT activation with decreased caspase 3/7 activity. Exogenous SPARC rapidly induces AKT phosphorylation, an effect that is blocked by a neutralizing SPARC antibody. Furthermore, AKT activation is essential for the anti-apoptotic effects of SPARC as the decreased apoptosis and caspase activity associated with SPARC expression can be blocked with dominant-negative AKT or a specific AKT inhibitor. As tumor cells face stressful microenvironments particularly during the process of invasion, these results suggest that SPARC functions, in part, to promote tumor progression by enabling tumor cells to survive under stressful conditions.

Authors
Shi, Q; Bao, S; Maxwell, JA; Reese, ED; Friedman, HS; Bigner, DD; Wang, X-F; Rich, JN
MLA Citation
Shi, Q, Bao, S, Maxwell, JA, Reese, ED, Friedman, HS, Bigner, DD, Wang, X-F, and Rich, JN. "Secreted protein acidic, rich in cysteine (SPARC), mediates cellular survival of gliomas through AKT activation." J Biol Chem 279.50 (December 10, 2004): 52200-52209.
PMID
15469933
Source
pubmed
Published In
The Journal of biological chemistry
Volume
279
Issue
50
Publish Date
2004
Start Page
52200
End Page
52209
DOI
10.1074/jbc.M409630200

ATR functions as a gene dosage-dependent tumor suppressor on a mismatch repair-deficient background.

The ataxia-telangiectasia mutated and rad3-related (ATR) kinase orchestrates cellular responses to DNA damage and replication stress. Complete loss of ATR function leads to chromosomal instability and cell death. However, heterozygous ATR mutations are found in human cancers with microsatellite instability, suggesting that ATR haploinsufficiency contributes to tumorigenesis. To test this possibility, we generated human cell line and mouse model systems in which a single ATR allele was inactivated on a mismatch repair (MMR)-deficient background. Monoallelic ATR gene targeting in MLH1-deficient HCT 116 colon carcinoma cells resulted in hypersensitivity to genotoxic stress accompanied by dramatic increases in fragile site instability, and chromosomal amplifications and rearrangements. The ATR(+/-) HCT 116 cells also displayed compromised activation of Chk1, an important downstream target for ATR. In complementary studies, we demonstrated that mice bearing the same Atr(+/-)/Mlh1(-/-) genotype were highly prone to both embryonic lethality and early tumor development. These results demonstrate that MMR proteins and ATR functionally interact during the cellular response to genotoxic stress, and that ATR serves as a haploinsufficient tumor suppressor in MMR-deficient cells.

Authors
Fang, Y; Tsao, C-C; Goodman, BK; Furumai, R; Tirado, CA; Abraham, RT; Wang, X-F
MLA Citation
Fang, Y, Tsao, C-C, Goodman, BK, Furumai, R, Tirado, CA, Abraham, RT, and Wang, X-F. "ATR functions as a gene dosage-dependent tumor suppressor on a mismatch repair-deficient background." EMBO J 23.15 (August 4, 2004): 3164-3174.
PMID
15282542
Source
pubmed
Published In
EMBO Journal
Volume
23
Issue
15
Publish Date
2004
Start Page
3164
End Page
3174
DOI
10.1038/sj.emboj.7600315

Casein kinase Iepsilon plays a functional role in the transforming growth factor-beta signaling pathway.

The transforming growth factor-beta (TGF-beta) signaling pathway is known to be involved in a wide range of biological events, including development, cellular differentiation, apoptosis, and oncogenesis. The TGF-beta signal is mediated by ligand binding to the type II receptor, leading to the recruitment and activation of the type I receptor, and subsequent activation of a family of intracellular signal transducing proteins called Smads. Here we report a regulatory role for casein kinase Iepsilon (CKIepsilon) in the TGF-beta signaling cascade. We find that CKIepsilon binds to all Smads and the cytoplasmic domains of the type I and type II receptors both in vitro and in vivo. The interaction of CKIepsilon with the type I and type II receptors is independent of TGF-beta stimulation, whereas the CKIepsilon/Smad interaction is transiently disrupted by ligand treatment. Additionally, CKIepsilon is able to phosphorylate the receptor-activated Smads (Smads 1-3 and 5) and the type II receptor in vitro. Transcriptional reporter assays reveal that transient overexpression of wild type CKIepsilon dramatically reduces basal reporter activity but enhances TGF-beta-stimulated transcription. Furthermore, overexpression of a kinase-dead mutant of CKIepsilon inhibits both basal and ligand-induced transcription, whereas inhibition of endogenous CKI catalytic activity with IC261 blocks only TGF-beta-stimulated reporter activity. Finally, knocking down CKIepsilon protein levels results in a significant increase in basal and TGF-beta-induced transcription. These results suggest that CKIepsilon plays a ligand-dependent, differential, and dual regulatory role within the TGF-beta signaling pathway.

Authors
Waddell, DS; Liberati, NT; Guo, X; Frederick, JP; Wang, X-F
MLA Citation
Waddell, DS, Liberati, NT, Guo, X, Frederick, JP, and Wang, X-F. "Casein kinase Iepsilon plays a functional role in the transforming growth factor-beta signaling pathway." The Journal of biological chemistry 279.28 (July 2004): 29236-29246.
PMID
15133026
Source
epmc
Published In
The Journal of biological chemistry
Volume
279
Issue
28
Publish Date
2004
Start Page
29236
End Page
29246
DOI
10.1074/jbc.m400880200

SB-431542, a small molecule transforming growth factor-beta-receptor antagonist, inhibits human glioma cell line proliferation and motility.

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that promotes malignant glioma invasion, angiogenesis, and immunosuppression. Antisense oligonucleotide suppression of TGF-beta(2) ligand expression has shown promise in preclinical and clinical studies but at least two ligands mediate the effects of TGF-beta in gliomas. Therefore, we examined the effects of SB-431542, a novel, small molecule inhibitor of the type I TGF-beta receptor, on a panel of human malignant glioma cell lines. SB-431542 blocked the phosphorylation and nuclear translocation of the SMADs, intracellular mediators of TGF-beta signaling, with decreased TGF-beta-mediated transcription. Furthermore, SB-431542 inhibited the expression of two critical effectors of TGF-beta-vascular endothelial growth factor and plasminogen activator inhibitor-1. SB-431542 treatment of glioma cultures inhibited proliferation, TGF-beta-mediated morphologic changes, and cellular motility. Together, our results suggest that small molecule inhibitors of TGF-beta receptors may offer a novel therapy for malignant gliomas by reducing cell proliferation, angiogenesis, and motility.

Authors
Hjelmeland, MD; Hjelmeland, AB; Sathornsumetee, S; Reese, ED; Herbstreith, MH; Laping, NJ; Friedman, HS; Bigner, DD; Wang, X-F; Rich, JN
MLA Citation
Hjelmeland, MD, Hjelmeland, AB, Sathornsumetee, S, Reese, ED, Herbstreith, MH, Laping, NJ, Friedman, HS, Bigner, DD, Wang, X-F, and Rich, JN. "SB-431542, a small molecule transforming growth factor-beta-receptor antagonist, inhibits human glioma cell line proliferation and motility." Mol Cancer Ther 3.6 (June 2004): 737-745.
PMID
15210860
Source
pubmed
Published In
Molecular cancer therapeutics
Volume
3
Issue
6
Publish Date
2004
Start Page
737
End Page
745

Acquired expression of periostin by human breast cancers promotes tumor angiogenesis through up-regulation of vascular endothelial growth factor receptor 2 expression.

The late stages of human breast cancer development are poorly understood complex processes associated with the expression of genes by cancers that promote specific tumorigenic activities, such as angiogenesis. Here, we describe the identification of periostin as a mesenchyme-specific gene whose acquired expression by human breast cancers leads to a significant enhancement in tumor progression and angiogenesis. Undetectable in normal human breast tissues, periostin was found to be overexpressed by the vast majority of human primary breast cancers examined. Tumor cell lines engineered to overexpress periostin showed a phenotype of accelerated growth and angiogenesis as xenografts in immunocompromised animals. The underlying mechanism of periostin-mediated induction of angiogenesis was found to derive in part from the up-regulation of the vascular endothelial growth factor receptor Flk-1/KDR by endothelial cells through an integrin alpha(v)beta(3)-focal adhesion kinase-mediated signaling pathway. These findings demonstrate the presence of a novel mechanism by which tumor angiogenesis is acquired with the expression of a mesenchyme-specific gene as a crucial step in late stages of tumorigenesis.

Authors
Shao, R; Bao, S; Bai, X; Blanchette, C; Anderson, RM; Dang, T; Gishizky, ML; Marks, JR; Wang, X-F
MLA Citation
Shao, R, Bao, S, Bai, X, Blanchette, C, Anderson, RM, Dang, T, Gishizky, ML, Marks, JR, and Wang, X-F. "Acquired expression of periostin by human breast cancers promotes tumor angiogenesis through up-regulation of vascular endothelial growth factor receptor 2 expression." Mol Cell Biol 24.9 (May 2004): 3992-4003.
PMID
15082792
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
24
Issue
9
Publish Date
2004
Start Page
3992
End Page
4003

Activin induces hepatocyte cell growth arrest through induction of the cyclin-dependent kinase inhibitor p15INK4B and Sp1

In this report, we examined the role of activin in the regulation of cell growth inhibition of human hepatocarcinoma cells. Using RNase protection assay for various cell cycle regulators and Western blotting experiments, we show that activin treatment of HepG2 cells leads to increased gene expression of the cyclin-dependent kinase inhibitor (CDKI) p15INK4B. Furthermore, transient co-transfection studies of the p15INK4B promoter/luciferase construct performed in HepG2 cells demonstrates that activin induction of the p15INK4B promoter is mediated through the Smad pathway. p15 INK4B gene promoter mapping analysis revealed a 66-bp region within the proximal domain of the promoter, which contains a consensus site for the transcription factor Sp1, as critical for mediating the activin effect on p15INK4B gene expression. Finally, gel mobility shift experiments, using the Sp1 consensus site, revealed increased DNA binding of Sp1 in response to activin treatment of HepG2 cells, further confirming the involvement of Sp1 in activin-mediated p15INK4B gene promoter activation. Together, our data indicates an important role for the cyclin-dependent kinase inhibitor p15INK4B in activin-induced cell cycle arrest in liver cells. © 2003 Elsevier Inc. All rights reserved.

Authors
Ho, J; Guise, CD; Kim, C; Lemay, S; Wang, X-F; Lebrun, J-J
MLA Citation
Ho, J, Guise, CD, Kim, C, Lemay, S, Wang, X-F, and Lebrun, J-J. "Activin induces hepatocyte cell growth arrest through induction of the cyclin-dependent kinase inhibitor p15INK4B and Sp1." Cellular Signalling 16.6 (2004): 693-701.
PMID
15093610
Source
scival
Published In
Cellular Signalling
Volume
16
Issue
6
Publish Date
2004
Start Page
693
End Page
701
DOI
10.1016/j.cellsig.2003.11.002

Transforming Growth Factor-β1 Inhibition of Vascular Smooth Muscle Cell Activation Is Mediated via Smad3

Activation of vascular smooth muscle cells (VSMCs) by proinflammatory cytokines is a key feature of atherosclerotic lesion formation. Transforming growth factor (TGF)-β1 is a pleiotropic growth factor that can modulate the inflammatory response in diverse cell types including VSMCs. However, the mechanisms by which TGF-β1 is able to mediate these effects remains incompletely understood. We demonstrate here that the ability of TGF-β1 to inhibit markers of VSMC activation, inducible nitric-oxide synthase (iNOS) and interleukin (IL)-6, is mediated through its downstream effector Smad3. In reporter gene transfection studies, we found that among a panel of Smads, Smad3 could inhibit iNOS induction in an analogous manner as exogenous TGF-β1. Adenoviral overexpression of Smad3 potently repressed inducible expression of endogenous iNOS and IL-6. Conversely, TGF-β1 inhibition of cytokine-mediated induction of iNOS and IL-6 expression was completely blocked in Smad3-deficient VSMCs. Previous studies demonstrate that CCAAT/enhancer-binding protein (C/EBP) and NF-κB sites are critical for cytokine induction of both the iNOS and IL-6 promoters. We demonstrate that the inhibitory effect of Smad3 occurs via a novel antagonistic effect of Smad3 on C/EBP DNA-protein binding and activity. Smad3 mediates this effect in part by inhibiting C/EBP-β and C/EBP-δ through distinct mechanisms. Furthermore, we find that Smad3 prevents the cooperative induction of the iNOS promoter by C/EBP and NF-κB. These data demonstrate that Smad3 plays an essential role in mediating TGF-β1 anti-inflammatory response in VSMCs.

Authors
Feinberg, MW; Watanabe, M; Lebedeva, MA; Depina, AS; Hanai, J-I; Mammoto, T; Frederick, JP; Wang, X-F; Sukhatme, VP; Jain, MK
MLA Citation
Feinberg, MW, Watanabe, M, Lebedeva, MA, Depina, AS, Hanai, J-I, Mammoto, T, Frederick, JP, Wang, X-F, Sukhatme, VP, and Jain, MK. "Transforming Growth Factor-β1 Inhibition of Vascular Smooth Muscle Cell Activation Is Mediated via Smad3." Journal of Biological Chemistry 279.16 (2004): 16388-16393.
PMID
14754879
Source
scival
Published In
Journal of Biological Chemistry
Volume
279
Issue
16
Publish Date
2004
Start Page
16388
End Page
16393
DOI
10.1074/jbc.M309664200

Essential Role for Smad3 in Regulating MCP-1 Expression and Vascular Inflammation

Transforming growth factor (TGF)-β1 is a pleiotropic growth factor with known inhibitory effects on immune cell activation. However, the specific mechanism(s) and in vivo significance of the effectors of TGF-β1 modulation in the context of vascular inflammation are not well characterized. The chemokine monocyte chemoattractant protein (MCP)-1 is critical for the recruitment of macrophages in inflammatory disease states. In this study, we provide definitive evidence that the ability of TGF-β1 to inhibit MCP-1 expression is mediated via its effector Smad3. Adenoviral overexpression of Smad3 potently repressed inducible expression of endogenous MCP-1. Conversely, TGF-β1 inhibition of cytokine-mediated induction of MCP-1 expression was completely blocked in Smad3-deficient macrophages. Consistent with this impaired response, cardiac allografts in Smad3-deficient mice developed accelerated intimal hyperplasia with increased infiltration of adventitial macrophages expressing MCP-1. Previous studies show that MCP-1 inducibility is regulated by an AP-1 complex composed of c-Jun/c-Fos heterodimers. We demonstrate that the inhibitory effect of Smad3 occurs via a novel antagonistic effect of Smad3 on AP-1 DNA-protein binding and activity. Thus, Smad3 plays an essential role in modulating vascular inflammation characteristic of transplant-associated arteriopathy, is important in regulating MCP-1 expression, and plays a critical role in the ability of TGF-β1 to repress stimuli from a major inflammatory signaling pathway.

Authors
Feinberg, MW; Shimizu, K; Lebedeva, M; Haspel, R; Takayama, K; Chen, Z; Frederick, JP; Wang, X-F; Simon, DI; Libby, P; Mitchell, RN; Jain, MK
MLA Citation
Feinberg, MW, Shimizu, K, Lebedeva, M, Haspel, R, Takayama, K, Chen, Z, Frederick, JP, Wang, X-F, Simon, DI, Libby, P, Mitchell, RN, and Jain, MK. "Essential Role for Smad3 in Regulating MCP-1 Expression and Vascular Inflammation." Circulation Research 94.5 (2004): 601-608.
PMID
14752027
Source
scival
Published In
Circulation Research
Volume
94
Issue
5
Publish Date
2004
Start Page
601
End Page
608
DOI
10.1161/01.RES.0000119170.70818.4F

Periostin potently promotes metastatic growth of colon cancer by augmenting cell survival via the Akt/PKB pathway

Molecular mechanisms associated with tumor metastasis remain poorly understood. Here we report that acquired expression of periostin by colon cancer cells greatly promoted metastatic development of colon tumors. Periostin is overexpressed in more than 80% of human colon cancers examined with highest expression in metastatic tumors. Periostin expression dramatically enhanced metastatic growth of colon cancer by both preventing stress-induced apoptosis in the cancer cells and augmenting endothelial cell survival to promote angiogenesis. At the molecular level, periostin activated the Akt/PKB signaling pathway through the αvβ3 integrins to increase cellular survival. These data demonstrated that the survival-promoting function is crucial for periostin to promote tumor metastasis of colon cancer.

Authors
Bao, S; Ouyang, G; Bai, X; Huang, Z; Ma, C; Liu, M; Shao, R; Anderson, RM; Rich, JN; Wang, X-F
MLA Citation
Bao, S, Ouyang, G, Bai, X, Huang, Z, Ma, C, Liu, M, Shao, R, Anderson, RM, Rich, JN, and Wang, X-F. "Periostin potently promotes metastatic growth of colon cancer by augmenting cell survival via the Akt/PKB pathway." Cancer Cell 5.4 (2004): 329-339.
PMID
15093540
Source
scival
Published In
Cancer Cell
Volume
5
Issue
4
Publish Date
2004
Start Page
329
End Page
339
DOI
10.1016/S1535-6108(04)00081-9

Transforming Growth Factor β-Mediated Transcriptional Repression of c-myc Is Dependent on Direct Binding of Smad3 to a Novel Repressive Smad Binding Element

Smad proteins are the most well-characterized intracellular effectors of the transforming growth factor β (TGF-β) signal. The ability of the Smads to act as transcriptional activators via TGF-β-induced recruitment to Smad binding elements (SBE) within the promoters of TGF-β target genes has been firmly established. However, the elucidation of the molecular mechanisms involved in TGF-β-mediated transcriptional repression are only recently being uncovered. The proto-oncogene c-myc is repressed by TGF-β, and this repression is required for the manifestation of the TGF-β cytostatic program in specific cell types. We have shown that Smad3 is required for both TGF-β-induced repression of c-myc and subsequent growth arrest in keratinocytes. The transcriptional repression of c-myc is dependent on direct Smad3 binding to a novel Smad binding site, termed a repressive Smad binding element (RSBE), within the TGF-β inhibitory element (TIE) of the c-myc promoter. The c-myc TIE is a composite element, comprised of an overlapping RSBE and a consensus E2F site, that is capable of binding at least Smad3, Smad4, E2F-4, and p107. The RSBE is distinct from the previously defined SBE and may partially dictate, in conjunction with the promoter context of the overlapping E2F site, whether the Smad3-containing complex actively represses, as opposed to transactivates, the c-myc promoter.

Authors
Frederick, JP; Liberati, NT; Waddell, DS; Shi, Y; Wang, X-F
MLA Citation
Frederick, JP, Liberati, NT, Waddell, DS, Shi, Y, and Wang, X-F. "Transforming Growth Factor β-Mediated Transcriptional Repression of c-myc Is Dependent on Direct Binding of Smad3 to a Novel Repressive Smad Binding Element." Molecular and Cellular Biology 24.6 (2004): 2546-2559.
PMID
14993291
Source
scival
Published In
Molecular and Cellular Biology
Volume
24
Issue
6
Publish Date
2004
Start Page
2546
End Page
2559
DOI
10.1128/MCB.24.6.2546-2559.2004

Transcriptional Activation of p21waf1/cip1 by Alkylphospholipids: Role of the Mitogen-Activated Protein Kinase Pathway in the Transactivation of the Human p21waf1/cip1 Promoter by Sp1

Alkylphospholipids (ALKs) are a novel class of antitumor agents with an unknown mechanism of action. The first ALK tested in the clinic, miltefosine, has been approved recently in Europe for the local treatment of patients with cutaneous metastasis. Perifosine, the only available oral ALK, is being studied currently in human cancer clinical trials. We have shown previously that perifosine induces p21waf1/cip1 in a p53-independent fashion and that induction of p21waf1/cip1 is required for the perifosine-induced cell cycle arrest because cell lines lacking p21 waf1/cip1 are refractory to perifosine. In this report, we investigated the mechanism by which perifosine induces p21waf1/cip1 protein expression. We observed that perifosine induces the accumulation of p21waf1/cip1 mRNA without affecting p21waf1/cip1 mRNA stability. Using several p21waf1/cip1 promoter-driven luciferase reporter plasmids, we observed that perifosine activates the 2.4-kb full-length p21waf1/cip1 promoter as well as a p21 promoter construct lacking p53-binding sites, suggesting that perifosine activates the p21 waf1/cip1 promoter independent of p53. The minimal p21 promoter region required for perifosine-induced p21 promoter activation contains four consensus Sp1-binding sites. Mutations in each particular Sp1 site block perifosine-induced p21waf1/cip1 expression. Moreover, we showed that perifosine activates the mitogen-activated protein/extracellular signal-regulated kinase pathway, and this activation promotes the phosphorylation of Sp1 in known mitogen-activated protein kinase residues (threonine 453 and 739), thereby leading to increased Sp1 binding and enhanced p21waf1/cip1 transcription. These results represent a novel mechanism by which alkylphospholipids modulate transcription, and may contribute to the discovery of new signal transduction pathways crucial for normal and neoplastic cell cycle control.

Authors
Siervi, AD; Marinissen, M; Diggs, J; Wang, X-F; Pages, G; Senderowicz, A
MLA Citation
Siervi, AD, Marinissen, M, Diggs, J, Wang, X-F, Pages, G, and Senderowicz, A. "Transcriptional Activation of p21waf1/cip1 by Alkylphospholipids: Role of the Mitogen-Activated Protein Kinase Pathway in the Transactivation of the Human p21waf1/cip1 Promoter by Sp1." Cancer Research 64.2 (2004): 743-750.
PMID
14744793
Source
scival
Published In
Cancer Research
Volume
64
Issue
2
Publish Date
2004
Start Page
743
End Page
750
DOI
10.1158/0008-5472.CAN-03-2505

Requirement of protein phosphatase 5 in DNA-damage-induced ATM activation

The checkpoint kinase ATM is centrally involved in the cellular response to DNA double-strand breaks. However, the mechanism of ATM activation during genotoxic stress is only partially understood. Here we report a direct regulatory linkage between the protein serine-threonine phosphatase 5 (PP5) and ATM. PP5 interacts with ATM in a DNA-damage-inducible manner. Reduced expression of PP5 attenuated DNA-damage-induced activation of ATM. Expression of a catalytically inactive PP5 mutant inhibited the phosphorylation of ATM substrates and the autophosphorylation of ATM on Ser 1981, and caused an S-phase checkpoint defect in DNA-damaged cells. Together our findings indicate that PP5 plays an essential role in the activation and checkpoint signaling functions of ATM in cells that have suffered DNA double-strand breaks.

Authors
Ali, A; Zhang, J; Bao, S; Liu, I; Otterness, D; Dean, NM; Abraham, RT; Wang, X-F
MLA Citation
Ali, A, Zhang, J, Bao, S, Liu, I, Otterness, D, Dean, NM, Abraham, RT, and Wang, X-F. "Requirement of protein phosphatase 5 in DNA-damage-induced ATM activation." Genes and Development 18.3 (2004): 249-254.
PMID
14871926
Source
scival
Published In
Genes and Development
Volume
18
Issue
3
Publish Date
2004
Start Page
249
End Page
254
DOI
10.1101/gad.1176004

Beta-arrestin 2 mediates endocytosis of type III TGF-beta receptor and down-regulation of its signaling.

beta-Arrestins bind to activated seven transmembrane-spanning (7TMS) receptors (G protein-coupled receptors) after the receptors are phosphorylated by G protein-coupled receptor kinases (GRKs), thereby regulating their signaling and internalization. Here, we demonstrate an unexpected and analogous role of beta-arrestin 2 (betaarr2) for the single transmembrane-spanning type III transforming growth factor-beta (TGF-beta) receptor (TbetaRIII, also referred to as betaglycan). Binding of betaarr2 to TbetaRIII was also triggered by phosphorylation of the receptor on its cytoplasmic domain (likely at threonine 841). However, such phosphorylation was mediated by the type II TGF-beta receptor (TbetaRII), which is itself a kinase, rather than by a GRK. Association with betaarr2 led to internalization of both receptors and down-regulation of TGF-beta signaling. Thus, the regulatory actions of beta-arrestins are broader than previously appreciated, extending to the TGF-beta receptor family as well.

Authors
Chen, W; Kirkbride, KC; How, T; Nelson, CD; Mo, J; Frederick, JP; Wang, X-F; Lefkowitz, RJ; Blobe, GC
MLA Citation
Chen, W, Kirkbride, KC, How, T, Nelson, CD, Mo, J, Frederick, JP, Wang, X-F, Lefkowitz, RJ, and Blobe, GC. "Beta-arrestin 2 mediates endocytosis of type III TGF-beta receptor and down-regulation of its signaling." Science 301.5638 (September 5, 2003): 1394-1397.
PMID
12958365
Source
pubmed
Published In
Science
Volume
301
Issue
5638
Publish Date
2003
Start Page
1394
End Page
1397
DOI
10.1126/science.1083195

Bone-related genes expressed in advanced malignancies induce invasion and metastasis in a genetically defined human cancer model.

We employed a genetically defined human cancer model to investigate the contributions of two genes up-regulated in several cancers to phenotypic changes associated with late stages of tumorigenesis. Specifically, tumor cells expressing two structurally unrelated bone-related genes, osteonectin and osteoactivin, acquired a highly invasive phenotype when implanted intracranially in immunocompromised mice. Mimicking a subset of gliomas, tumor cells invaded brain along blood vessels and developed altered vasculature at the brain-tumor interface, suggesting that production of those two proteins by tumor cells may create a complex relationship between invading tumor and vasculature co-opted during tumor invasion. Interestingly, the same tumor cells formed massive spontaneous metastases when implanted subcutaneously. This dramatic alteration in tumor phenotype indicates that cellular microenvironment plays an important role in defining the specific effects of those gene products in tumor behavior. In vitro examination of tumor cells expressing either osteonectin or osteoactivin revealed that there was no impact on cellular growth or death but increased invasiveness and expression of MMP-9 and MMP-3. Specific pharmacologic inhibitors of MMP-2/9 and MMP-3 blocked the increased in vitro invasion associated with osteoactivin expression, but only MMP-3 inhibition altered the invasive in vitro phenotype mediated by osteonectin. Results from this genetically defined model system are supported by similar findings obtained from several established tumor cell lines derived originally from human patients. In sum, these results reveal that the expression of a single bone-related gene can dramatically alter or modify tumor cell behavior and may confer differential growth characteristics in different microenvironments. Genetically defined human cancer models offer useful tools in functional genomics to define the roles of specific genes in late stages of carcinogenesis.

Authors
Rich, JN; Shi, Q; Hjelmeland, M; Cummings, TJ; Kuan, C-T; Bigner, DD; Counter, CM; Wang, X-F
MLA Citation
Rich, JN, Shi, Q, Hjelmeland, M, Cummings, TJ, Kuan, C-T, Bigner, DD, Counter, CM, and Wang, X-F. "Bone-related genes expressed in advanced malignancies induce invasion and metastasis in a genetically defined human cancer model." J Biol Chem 278.18 (May 2, 2003): 15951-15957.
PMID
12590137
Source
pubmed
Published In
The Journal of biological chemistry
Volume
278
Issue
18
Publish Date
2003
Start Page
15951
End Page
15957
DOI
10.1074/jbc.M211498200

Human T-cell leukemia virus type 1 tax activates cyclin-dependent kinase inhibitor p21/Waf1/Cip1 expression through a p53-independent mechanism: Inhibition of cdk2

We investigated the possible involvement of HTLV-1 Tax in the transcriptional activation of p21/Waf1/Cip1 (hereafter p21), a potent inhibitor of cyclin-dependent kinases and cell growth. Tax transfection resulted in enhanced expression of p21 protein in T and fibroblastoid cells. Similarly, Tax-expressing cells have higher amounts of endogenous p21 protein and RNA. However, neither Tax-negative, HTLV-1 transformed cells or HTLV-1-negative T cell lines had detectable levels of p21 protein and RNA. Cotransfection of Tax strongly activated the p21 promoter. CREB/ATF defective Tax mutant (M47) activated the p21 promoter significantly less efficiently. Tax activated wild type (wt) p21 promoter in p53-negative Jurkat and p53-positive A301 cells, irrespective of endogenous p53 status, and activated a mutant p21 promoter containing a p53 responsive element (p53RE) deletion as strongly as wt promoter. Of importance, cdk2 activity was almost completely abolished in Tax-induced p21-expressing MT-2 cells, suggesting that Tax-induced p21 predominantly affects the activity of cdk2, a late G1 and S phase kinase. Taken together, these findings suggest that HTLV-1 Tax activates p21/Waf1/Cip1, a cell growth inhibitor, in a p53-independent mechanism through CREB/ATF-related transcription factors, and inhibits cdk2. Tax induction of p21 may balance the T-cell proliferation function of Tax and may contribute to the long clinical latency of HTLV-1 infection and the delayed development of adult T-cell leukemia. © 2003 Wiley-Liss, Inc.

Authors
Chowdhury, IH; Farhadi, A; Wang, X-F; Robb, ML; Birx, DL; Kim, JH
MLA Citation
Chowdhury, IH, Farhadi, A, Wang, X-F, Robb, ML, Birx, DL, and Kim, JH. "Human T-cell leukemia virus type 1 tax activates cyclin-dependent kinase inhibitor p21/Waf1/Cip1 expression through a p53-independent mechanism: Inhibition of cdk2." International Journal of Cancer 107.4 (2003): 603-611.
PMID
14520699
Source
scival
Published In
International Journal of Cancer
Volume
107
Issue
4
Publish Date
2003
Start Page
603
End Page
611
DOI
10.1002/ijc.11316

HIV-1 Vpr activates cell cycle inhibitor p21/Waf1/Cip1: A potential mechanism of G2/M cell cycle arrest

The Vpr gene of human immunodeficiency virus type 1 (HIV-1) encodes a 14-kDa protein that prevents cell proliferation by causing arrest in the G2/M phase of the cell cycle. Here we report the first evidence that Vpr activates the expression and transcription of the cyclin-dependent kinase inhibitor p21/Waf1/Cip1 (hereafter p21), an inhibitor of the G1 and G2/M phase transitions in T lymphoid and myeloid cells. Vpr activated p21 protein expression in a dose-dependent manner. Vpr also caused a three- to eightfold induction of the p21 promoter. This induction was dose- and time-dependent and was comparable to levels of p21 induction induced by p53. Of note, Vpr activated p21 transcription in endogenous p53 positive cells, but not in p53-deleted or p53 nonfunctional cells. Vpr and p53 had an additive effect on p21 transcription. Mutational analysis indicated that wt Vpr, but not cell cycle inactive Vpr mutants, activated the p21 promoter. These data demonstrate that HIV-1 Vpr utilizes the cyclin-dependent kinase inhibitor p21, in addition to cdc2, to arrest cells in G2/M. © 2003 Elsevier Science (USA).

Authors
Chowdhury, IH; Wang, X-F; Landau, NR; Robb, ML; Polonis, VR; Birx, DL; Kim, JH
MLA Citation
Chowdhury, IH, Wang, X-F, Landau, NR, Robb, ML, Polonis, VR, Birx, DL, and Kim, JH. "HIV-1 Vpr activates cell cycle inhibitor p21/Waf1/Cip1: A potential mechanism of G2/M cell cycle arrest." Virology 305.2 (2003): 371-377.
PMID
12573582
Source
scival
Published In
Virology
Volume
305
Issue
2
Publish Date
2003
Start Page
371
End Page
377
DOI
10.1006/viro.2002.1777

Smad3 deficiency attenuates bleomycin-induced pulmonary fibrosis in mice.

Transforming growth factor-beta (TGF-beta) signaling plays an important regulatory role during lung fibrogenesis. Smad3 was identified in the pathway for transducing TGF-beta signals from the cell membrane to the nucleus. Using mice without Smad3 gene expression, we investigated whether Smad3 could regulate bleomycin-induced pulmonary fibrosis in vivo. Mice deficient in Smad3 demonstrated suppressed type I procollagen mRNA expression and reduced hydroxyproline content in the lungs compared with wild-type mice treated with bleomycin. Furthermore, loss of Smad3 greatly attenuated morphological fibrotic responses to bleomycin in the mouse lungs, suggesting that Smad3 is implicated in the pathogenesis of pulmonary fibrosis. These results show that Smad3 contributes to bleomycin-induced lung injury and that Smad3 may serve as a novel target for potential therapeutic treatment of lung fibrosis.

Authors
Zhao, J; Shi, W; Wang, Y-L; Chen, H; Bringas, P; Datto, MB; Frederick, JP; Wang, X-F; Warburton, D
MLA Citation
Zhao, J, Shi, W, Wang, Y-L, Chen, H, Bringas, P, Datto, MB, Frederick, JP, Wang, X-F, and Warburton, D. "Smad3 deficiency attenuates bleomycin-induced pulmonary fibrosis in mice." American journal of physiology. Lung cellular and molecular physiology 282.3 (March 2002): L585-L593.
PMID
11839555
Source
epmc
Published In
American journal of physiology. Lung cellular and molecular physiology
Volume
282
Issue
3
Publish Date
2002
Start Page
L585
End Page
L593
DOI
10.1152/ajplung.00151.2001

Smad3 deficiency attenuates bleomycin-induced pulmonary fibrosis in mice

Transforming growth factor-β (TGF-β) signaling plays an important regulatory role during lung fibrogenesis. Smad3 was identified in the pathway for transducing TGF-β signals from the cell membrane to the nucleus. Using mice without Smad3 gene expression, we investigated whether Smad3 could regulate bleomycin-induced pulmonary fibrosis in vivo. Mice deficient in Smad3 demonstrated suppressed type I procollagen mRNA expression and reduced hydroxyproline content in the lungs compared with wild-type mice treated with bleomycin. Furthermore, loss of Smad3 greatly attenuated morphological fibrotic responses to bleomycin in the mouse lungs, suggesting that Smad3 is implicated in the pathogenesis of pulmonary fibrosis. These results show that Smad3 contributes to bleomycin-induced lung injury and that Smad3 may serve as a novel target for potential therapeutic treatment of lung fibrosis.

Authors
Zhao, J; Shi, W; Wang, Y-L; Chen, H; Jr, PB; Datto, MB; Frederick, JP; Wang, X-F; Warburton, D
MLA Citation
Zhao, J, Shi, W, Wang, Y-L, Chen, H, Jr, PB, Datto, MB, Frederick, JP, Wang, X-F, and Warburton, D. "Smad3 deficiency attenuates bleomycin-induced pulmonary fibrosis in mice." American Journal of Physiology - Lung Cellular and Molecular Physiology 282.3 26-3 (2002): L585-L593.
Source
scival
Published In
American journal of physiology. Lung cellular and molecular physiology
Volume
282
Issue
3 26-3
Publish Date
2002
Start Page
L585
End Page
L593

HDAC6 is a microtubule-associated deacetylase

Reversible acetylation of α-tubulin has been implicated in regulating microtubule stability and function. The distribution of acetylated α-tubulin is tightly controlled and stereotypic. Acetylated α-tubulin is most abundant in stable microtubules but is absent from dynamic cellular structures such as neuronal growth cones and the leading edges of fibroblasts. However, the enzymes responsible for regulating tubulin acetylation and deacetylation are not known. Here we report that a member of the histone deacetylase family, HDAC6, functions as a tubulin deacetylase. HDAC6 is localized exclusively in the cytoplasm, where it associates with microtubules and localizes with the microtubule motor complex containing p150glued (ref. 3). In vivo, the overexpression of HDAC6 leads to a global deacetylation of α-tubulin, whereas a decrease in HDAC6 increases α-tubulin acetylation. In vitro, purified HDAC6 potently deacetylates α-tubulin in assembled microtubules. Furthermore, overexpression of HDAC6 promotes chemotactic cell movement, supporting the idea that HDAC6-mediated deacetylation regulates microtubule-dependent cell motility. Our results show that HDAC6 is the tubulin deacetylase, and provide evidence that reversible acetylation regulates important biological processes beyond histone metabolism and gene transcription.

Authors
Hubbert, C; Guardiola, A; Shao, R; Kawaguchi, Y; Ito, A; Nixon, A; Yoshida, M; Wang, X-F; Yao, T-P
MLA Citation
Hubbert, C, Guardiola, A, Shao, R, Kawaguchi, Y, Ito, A, Nixon, A, Yoshida, M, Wang, X-F, and Yao, T-P. "HDAC6 is a microtubule-associated deacetylase." Nature 417.6887 (2002): 455-458.
PMID
12024216
Source
scival
Published In
Nature
Volume
417
Issue
6887
Publish Date
2002
Start Page
455
End Page
458
DOI
10.1038/417455a

Smads "freeze" when they Ski

The transforming growth factor-β (TGF-β) signal is manifest through activated heteromeric Smad complex-mediated transcriptional modulation of target genes that translates into diverse, context-specific biologic effects, such as the potent TGF-β-initiated cytostatic program. The TGF-β pathway is effectively antagonized through the direct binding and subsequent repression of activated Smad heteromeric complexes by the Ski family of proto-oncoproteins.

Authors
Frederick, JP; Wang, X-F
MLA Citation
Frederick, JP, and Wang, X-F. "Smads "freeze" when they Ski." Structure 10.12 (2002): 1607-1611.
PMID
12467567
Source
scival
Published In
Structure
Volume
10
Issue
12
Publish Date
2002
Start Page
1607
End Page
1611
DOI
10.1016/S0969-2126(02)00914-0

Transforming growth factor β1 dysregulation in a human oral carcinoma tumour progression model

A human oral tumour progression model was established that consists of normal epithelial cells and three cell lines representing stages from dysplastic to metastatic cells. To investigate the impact of exogenous transforming growth factor-β1 on this model system, we analysed the responsiveness of those cells to transforming growth factor-β1 and explored the potential mechanism underlying the transforming growth factor-β1 activity. We found that the growth of all cell types, regardless of their stage of tumour progression, is inhibited by transforming growth factor-β1, although to different degrees. Transforming growth factor-β1 induced the expression of cyclin-dependent kinase inhibitors p15INK4B, p21WAF1/CIP1 and p27KIP1. In contrast, transforming growth factor-β1 was found to stimulate the invasive potential of one cell type that represents the most advanced stage of tumour phenotype, suggesting that the impact of transforming growth factor-β1 on functional features of tumour cells other than cellular proliferation may play a significant role in the process of oral tumour progression.

Authors
Hsu, S; Borke, JL; Lewis, JB; Singh, B; Aiken, AC; Huynh, CT; Schuster, GS; Caughman, GB; Dickinson, DP; Smith, AK; Osaki, T; Wang, XF
MLA Citation
Hsu, S, Borke, JL, Lewis, JB, Singh, B, Aiken, AC, Huynh, CT, Schuster, GS, Caughman, GB, Dickinson, DP, Smith, AK, Osaki, T, and Wang, XF. "Transforming growth factor β1 dysregulation in a human oral carcinoma tumour progression model." Cell Proliferation 35.3 (2002): 183-192.
PMID
12027954
Source
scival
Published In
Cell Proliferation
Volume
35
Issue
3
Publish Date
2002
Start Page
183
End Page
192
DOI
10.1046/j.1365-2184.2002.00237.x

The loss of Smad3 results in a lower rate of bone formation and osteopenia through dysregulation of osteoblast differentiation and apoptosis.

Smad3 is a well-characterized intracellular effector of the transforming growth factor beta (TGF-beta) signaling pathway and was implicated recently in the potentiation of vitamin D receptor (VDR)-mediated signaling. Given that both TGF-beta and vitamin D are important regulators of bone remodeling, it is expected that Smad3 plays an integral role in normal maintenance of bone. However, the exact mechanisms by which Smad3 functions in bone remodeling are unknown. Here, we show that mice with targeted deletion of Smad3 are osteopenic with less cortical and cancellous bone compared with wild-type littermates. Decreases in bone mineral density (BMD) in Smad3 null mice reflect the inability of osteoblasts to balance osteoclast activity, although osteoclast numbers are normal and vitamin D mediated serum calcium homeostasis is maintained. The osteopenia of Smad3 null mice is attributed to a decreased rate of bone formation associated with increased osteocyte number and apoptosis. These findings are supported by studies with isolated primary osteoblasts that show TGF-beta can no longer inhibit the differentiation of osteoblasts in the absence of Smad3; yet, TGF-beta-stimulated proliferation remains intact. Together these data support a model that a loss of Smad3 increases the osteocyte fate of the osteoblast and decreases the duration of osteoblast function by shortening lifespan, ultimately resulting in osteopenia.

Authors
Borton, AJ; Frederick, JP; Datto, MB; Wang, XF; Weinstein, RS
MLA Citation
Borton, AJ, Frederick, JP, Datto, MB, Wang, XF, and Weinstein, RS. "The loss of Smad3 results in a lower rate of bone formation and osteopenia through dysregulation of osteoblast differentiation and apoptosis." J Bone Miner Res 16.10 (October 2001): 1754-1764.
PMID
11585338
Source
pubmed
Published In
Journal of Bone and Mineral Research
Volume
16
Issue
10
Publish Date
2001
Start Page
1754
End Page
1764
DOI
10.1359/jbmr.2001.16.10.1754

The activity of guanine exchange factor NET1 is essential for transforming growth factor-beta-mediated stress fiber formation.

To examine signaling pathways underlying transforming growth factor-beta (TGF-beta)-mediated changes in cell morphology, we used a microarray system to identify downstream target genes that may play a role in this process. Through this approach, we found that the NET1 gene was induced upon TGF-beta treatment in several cell types. NET1 is a guanine nucleotide exchange factor for RhoA whose activity has been implicated in stress fiber formation. In the Swiss 3T3 cell line, TGF-beta induces NET1 expression, and this correlated with an increase in stress fiber formation. Overexpression of the wild type NET1 gene increases stress fiber formation, and overexpression of a dominant negative NET1 mutant (L392E) prevented TGF-beta dependent increase in stress fiber formation. Furthermore, treatment of the cells with a RhoA kinase inhibitor Y-27632 blocks TGF-beta-induced stress fiber formation. By using a stable cell line expressing dominant negative Smad3, we found that the Smad signaling pathway is essential for the induction of NET1, which in turn leads to the increase of Rho activity. Taken together, those data suggest that induction of NET1 is important for the increase of Rho activity upon TGF-beta treatment, which may represent the critical trigger for a variety of downstream events in different cells. Our results support the presence of a novel signaling pathway by which TGF-beta may regulate the formation of stress fibers and reorganization of cytoskeletal structures.

Authors
Shen, X; Li, J; Hu, PP; Waddell, D; Zhang, J; Wang, XF
MLA Citation
Shen, X, Li, J, Hu, PP, Waddell, D, Zhang, J, and Wang, XF. "The activity of guanine exchange factor NET1 is essential for transforming growth factor-beta-mediated stress fiber formation." J Biol Chem 276.18 (May 4, 2001): 15362-15368.
PMID
11278519
Source
pubmed
Published In
The Journal of biological chemistry
Volume
276
Issue
18
Publish Date
2001
Start Page
15362
End Page
15368
DOI
10.1074/jbc.M009534200

A genetically tractable model of human glioma formation.

Gliomas remain one of the deadliest forms of cancer. Improved therapeutics will require a better understanding of the molecular nature of these tumors. We, therefore, mimicked the most common genetic changes found in grade III-IV gliomas, disruption of the p53 and RB pathways and activation of telomere maintenance and independence from growth factors, through the ectopic expression of the SV40 T/t-Ag oncogene, an oncogenic form of H-ras (H-ras(V12G)), and the human telomerase catalytic subunit hTERT in normal human astrocytes. The resulting cells displayed many of the hallmarks of grade III-IV gliomas, including greatly expanded life span and growth in soft agar and, most importantly, were tumorigenic with pathology consistent with grade III-IV neuroectodermal tumors in mice. This model system will, for the first time, allow the biological significance of selected genetic alterations to be studied in human gliomas.

Authors
Rich, JN; Guo, C; McLendon, RE; Bigner, DD; Wang, XF; Counter, CM
MLA Citation
Rich, JN, Guo, C, McLendon, RE, Bigner, DD, Wang, XF, and Counter, CM. "A genetically tractable model of human glioma formation." Cancer Res 61.9 (May 1, 2001): 3556-3560.
PMID
11325817
Source
pubmed
Published In
Cancer Research
Volume
61
Issue
9
Publish Date
2001
Start Page
3556
End Page
3560

Transforming growth factor-beta signaling in cancer.

Transforming growth factor (TGF-beta) is a multifunctional polypeptide implicated in the regulation of a variety of cellular processes including growth, differentiation, apoptosis, adhesion, and motility. Abnormal activation or inhibition of these TGF-beta regulated processes is implicated in many diseases, including cancer. Cancers can develop through selective exploitation of defects in TGF-beta signaling that occur at several different levels in the pathway. The TGF-beta signal transduction cascade is initiated when TGF-beta binds to transmembrane receptors. The TGF-beta receptors then phosphorylate and activate Smad proteins, which transduce the signal from the cytoplasm to the nucleus. In the nucleus, Smads can bind directly to DNA and cooperate with other transcription factors to induce transcription of TGF-beta target genes. Mutations in target genes, Smads, or the TGF-beta receptor are associated with certain human cancers.

Authors
Rich, J; Borton, A; Wang, X
MLA Citation
Rich, J, Borton, A, and Wang, X. "Transforming growth factor-beta signaling in cancer." Microsc Res Tech 52.4 (February 15, 2001): 363-373. (Review)
PMID
11170295
Source
pubmed
Published In
Microscopy Research and Technique
Volume
52
Issue
4
Publish Date
2001
Start Page
363
End Page
373
DOI
10.1002/1097-0029(20010215)52:4<363::AID-JEMT1021>3.0.CO;2-F

An Essential Role for Mad Homology Domain 1 in the Association of Smad3 with Histone Deacetylase Activity

The Smads are a family of sequence-specific DNA-binding proteins that modulate transcription in response to transforming growth factor β (TGFβ) by recruiting transcriptional activators like the histone acetyltransferase, p300/CBP, or repressors like the histone deacetylase, HDAC1, to TGFβ target genes. The association of Smads and HDAC1 is mediated in part by direct binding of Smads to the HDAC1-associated proteins, TG-interacting factor, c-ski, and SnoN. Although ectopic expression of these proteins inhibits Smad-activated transcription, the contribution of histone deacetylase enzymatic activity to transcriptional repression by TGFβ is unknown. Here, the biological requirements for the interaction between Smads and endogenous histone deacetylase activity are investigated. We identify residues in Mad homology domain 1 of Smad3 that are required for association with histone deacetylase activity. An amino acid change at one of these critical residues does not disrupt the association of Smad3 with c-ski, SnoN, and transforming growth-interacting factor but does abrogate the ability of Smad3 to repress transcription. These findings indicate that the association of Smad3 and histone deacetylase activity relies on additional protein mediators that make contact with Smad3 at its amino terminus. Moreover, these data suggest that the suppressive effect of Smad3 on transcription is dependent upon its association with histone deacetylase enzymatic activity.

Authors
Liberati, NT; Moniwa, M; Borton, AJ; Davie, JR; Wang, X-F
MLA Citation
Liberati, NT, Moniwa, M, Borton, AJ, Davie, JR, and Wang, X-F. "An Essential Role for Mad Homology Domain 1 in the Association of Smad3 with Histone Deacetylase Activity." Journal of Biological Chemistry 276.25 (2001): 22595-22603.
PMID
11306568
Source
scival
Published In
Journal of Biological Chemistry
Volume
276
Issue
25
Publish Date
2001
Start Page
22595
End Page
22603
DOI
10.1074/jbc.M010778200

ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic responses

Genotoxic stress triggers the activation of checkpoints that delay cell-cycle progression to allow for DNA repair. Studies in fission yeast implicate members of the Rad family of checkpoint proteins, which includes Rad17, Rad1, Rad9 and Hus1, as key early-response elements during the activation of both the DNA damage and replication checkpoints. Here we demonstrate a direct regulatory linkage between the human Rad17 homologue (hRad17) and the checkpoint kinases, ATM and ATR. Treatment of human cells with genotoxic agents induced ATM/ATR-dependent phosphorylation of hRad17 at Ser 635 and Ser 645. Overexpression of a hRad17 mutant (hRad17AA) bearing Ala substitutions at both phosphorylation sites abrogated the DNA-damage-induced G2 checkpoint, and sensitized human fibroblasts to genotoxic stress. In contrast to wild-type hRad17, the hRad17AA mutant showed no ionizing-radiation-inducible association with hRad1, a component of the hRad1-hRad9-hHus1 checkpoint complex. These findings demonstrate that ATR/ATM-dependent phosphorylation of hRad17 is a critical early event during checkpoint signalling in DNA-damaged cells.

Authors
Bao, S; Tibbetts, RS; Brumbaugh, KM; Fang, Y; Richardson, DA; Ali, A; Chen, SM; Abraham, RT; Wang, X-F
MLA Citation
Bao, S, Tibbetts, RS, Brumbaugh, KM, Fang, Y, Richardson, DA, Ali, A, Chen, SM, Abraham, RT, and Wang, X-F. "ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic responses." Nature 411.6840 (2001): 969-974.
PMID
11418864
Source
scival
Published In
Nature
Volume
411
Issue
6840
Publish Date
2001
Start Page
969
End Page
974
DOI
10.1038/35082110

The role of Smad3 in mediating mouse hepatic stellate cell activation

Transforming growth factor β(TGF-β) is the most potent profibrogenic mediator in liver fibrosis. Although Smad proteins have been identified as intracellular mediators in the TGF-β signaling pathway, the function of individual Smad proteins remains poorly understood. The aim of this study was to explore the contribution of Smad3 in mediating TGF-β responses in a model of acute liver injury in vivo and in culture-activated hepatic stellate cells (HSCs). Wild-type, Smad3 heterozygous or Smad3 homozygous knockout mice were treated with a single intragastric administration of CCl4. After 72 hours, the induction of hepatic collagen α1(I) and α2(I) messenger RNA (mRNA) levels in Smad3 knock-out mice was only 42% and 64%, respectively, of the levels induced in wild-type mice. However, smooth muscle α-actin (α-SMA) was expressed at a slightly higher level in livers from knockout mice compared with wild-type mice. In culture-activated HSCs from Smad3 knockout mice, collagen α1(I) mRNA was 73% of wild-type HSCs, but α-SMA expression was the same. HSCs from knockout mice showed a higher proliferation rate than wild-type HSCs. Smad3-deficient HSCs did not form TGF-β1-induced Smad-containing DNA-binding complexes. In conclusion, (1) maximal expression of collagen type I in activated HSCs requires Smad3 in vivo and in culture; (2) Smad3 is not necessary for HSC activation as assessed by α-SMA expression; (3) Smad3 is necessary for inhibition of proliferation of HSCs, which might be TGF-β-dependent; and (4) Smad3 is required for TGF-β1-mediated Smad-containing DNA-binding complex formation in cultured HSCs.

Authors
Schnabl, B; Kweon, YO; Frederick, JP; Wang, X-F; Rippe, RA; Brenner, DA
MLA Citation
Schnabl, B, Kweon, YO, Frederick, JP, Wang, X-F, Rippe, RA, and Brenner, DA. "The role of Smad3 in mediating mouse hepatic stellate cell activation." Hepatology 34.1 (2001): 89-100.
PMID
11431738
Source
scival
Published In
Hepatology
Volume
34
Issue
1
Publish Date
2001
Start Page
89
End Page
100
DOI
10.1053/jhep.2001.25349

The Smads: transcriptional regulation and mouse models.

The field of transforming growth factor-beta (TGF-beta) signaling sees periodic discoveries that revolutionize our thinking, redirect our experiments, and peak our excitement. One of the first such discoveries was less than a decade ago: the molecular cloning of the type I and type II TGF-beta receptors. This breakthrough defined a novel family of serine/threonine kinase receptors, which led to the description of an ever-expanding superfamily. The discovery of how these receptors are grouped on the cell surface, bind TGF-beta and are activated by specific phosphorylation events further defined the uniqueness of this system in comparison to other families of growth factor receptors. Now, once again, the TGF-beta field has been revolutionized. This time, the discovery is the Smad family of proteins. Although one can hardly imagine TGF-beta without the Smads, the cloning of the Smads and their implication in TGF-beta signaling was only four years ago. Since that time, great advances have been made in our understanding of the Smads as transcription factors, which are activated by receptor mediated phosphorylation. In addition, animal models for a loss of Smad function have provided insight into the role of specific Smads in a variety of physiologic systems. The Smad field has been growing exponentially. A comprehensive review of all aspects of the Smads, therefore, would be beyond the scope of a single review. Instead, this review highlights some of the general aspects of Smad function, and then focuses on the role of specific Smad family members in transcriptional regulation, animal physiology, and disease processes.

Authors
Datto, M; Wang, XF
MLA Citation
Datto, M, and Wang, XF. "The Smads: transcriptional regulation and mouse models." Cytokine Growth Factor Rev 11.1-2 (March 2000): 37-48. (Review)
PMID
10708951
Source
pubmed
Published In
Cytokine & Growth Factor Reviews
Volume
11
Issue
1-2
Publish Date
2000
Start Page
37
End Page
48

Acrylamide-regulated neurofilament expression in rat pheochromocytoma cells.

Using the rat pheochromocytoma cell line (PC12), we present molecular evidence that the neurotoxicant acrylamide directly induces neurofilament gene expression, and the signaling pathways are initially distinctive from, but eventually merged into, that for nerve growth factor (NGF)-induced neurofilament expression. In PC12 cells, acrylamide increased neurofilament protein levels and synthesis. Acrylamide had no effect on the stability of neurofilament mRNAs suggesting that it directly increased neurofilament mRNA synthesis. K252a, a selective inhibitor for NGF receptor gp140trk, had no effect on acrylamide induction, but completely inhibited NGF-induced neurofilament protein synthesis. Therefore, the initial step for acrylamide signaling was distinctive from NGF. Dexamethasone reversed the effects of both NGF and acrylamide on neurofilament protein levels and synthesis indicated that there is a dexamethasone-sensitive signaling step upon which NGF and acrylamide merge, suggesting involvement of transcription-activating proteins like AP-1. These results, taken together with previous studies of transgenic mice that overexpress neurofilament genes, may partially explain the mechanisms of neurofilament accumulation in distal parts of large axons, a pathognomonic feature of acrylamide neurotoxicity in animals.

Authors
Lin, WW; Friedman, MA; Wang, XF; Abou-Donia, MB
MLA Citation
Lin, WW, Friedman, MA, Wang, XF, and Abou-Donia, MB. "Acrylamide-regulated neurofilament expression in rat pheochromocytoma cells." Brain Res 852.2 (January 10, 2000): 297-304.
PMID
10678756
Source
pubmed
Published In
Brain Research
Volume
852
Issue
2
Publish Date
2000
Start Page
297
End Page
304

The MEK pathway is required for stimulation of p21(WAF1/CIP1) by transforming growth factor-beta.

Transforming growth factor-beta (TGF-beta)can induce the cyclin-dependent kinase inhibitors p21 and p15 in a variety of cell types. We have shown previously that Smad3 is required for the growth inhibitory activity of TGF-beta, whereas overexpression of Smads is not sufficient to activate the expression of p21 in HaCaT cells. These data suggest that an additional signaling pathway may be involved in stimulating p21 in HaCaT cells. Given the recent finding that the mitogen-activated protein kinase (MAPK) pathway can cause p21 induction and arrest cells, we examined the involvement of this pathway for p21 and p15 induction by TGF-beta. We found that TGF-beta can regulate the MAPK pathway, leading to the increased transactivation ability of transcription factor Elk. Constitutively active components in the MAPK pathway activate p21 expression, and inhibitors or dominant negative constructs for the MAPK pathway significantly decrease p21 induction by TGF-beta. Both constitutively active MEK and inhibitors for MEK have no effect on Smad activity, including DNA binding, localization, and interaction with coactivator p300/CBP. These findings suggest that the MAPK pathway may be an independent pathway that is involved in p21 and p15 induction by TGF-beta.

Authors
Hu, PP; Shen, X; Huang, D; Liu, Y; Counter, C; Wang, XF
MLA Citation
Hu, PP, Shen, X, Huang, D, Liu, Y, Counter, C, and Wang, XF. "The MEK pathway is required for stimulation of p21(WAF1/CIP1) by transforming growth factor-beta." J Biol Chem 274.50 (December 10, 1999): 35381-35387.
PMID
10585406
Source
pubmed
Published In
The Journal of biological chemistry
Volume
274
Issue
50
Publish Date
1999
Start Page
35381
End Page
35387

Transforming growth factor-beta-mediated p15(INK4B) induction and growth inhibition in astrocytes is SMAD3-dependent and a pathway prominently altered in human glioma cell lines.

We sought to characterize the pathway by which the multifunctional cytokine transforming growth factor-beta (TGF-beta) inhibits the proliferation of normal astrocytes, and we analyzed the alterations in the TGF-beta pathway in human glioma cell lines. Upon TGF-beta treatment, primary rat astrocytes showed a significant decrease in DNA synthesis upon thymidine incorporation with a cell cycle arrest in the G(1) phase. Western analysis of the astrocytes revealed that the expression of the cyclin-dependent kinase inhibitor (CdkI) p15(INK4B) was significantly up-regulated upon TGF-beta treatment without a change in other CdkI levels. The retinoblastoma protein (Rb) became hypophosphorylated, and Cdk2 activity decreased. Analysis of Smad3 null mouse astrocytes showed a significant loss of both TGF-beta-mediated growth inhibition and p15(INK4B) induction compared with wild-type mouse astrocytes. Infection of rat astrocytes by SMAD3 and SMAD4 adenoviruses failed to induce increased expression of p15(INK4B), implying indirect transcriptional regulation of p15(INK4B) by SMAD3. High-grade human gliomas secrete TGF-beta, yet are resistant to its growth inhibitory effects. Analysis of the effects of TGF-beta on 12 human glioma cell lines showed that TGF-beta mildly inhibited the growth of six lines, had no effect on four lines, and stimulated the growth of two lines. The majority of glioma lines had homozygous deletions of the p15(INK4B) gene, except for two lines that expressed p15(INK4B) protein, which was induced further upon TGF-beta treatment. Three lines mildly induced CdkI p21(WAF1) expression in response to TGF-beta. Most tumor lines retained other TGF-beta-mediated responses, including extracellular matrix protein and angiogenic factor secretion, which may contribute to increased malignant behavior. This suggests that the loss of p15(INK4B) may explain, in part, the selective loss of growth inhibition by TGF-beta in gliomas to form a more aggressive tumor phenotype.

Authors
Rich, JN; Zhang, M; Datto, MB; Bigner, DD; Wang, XF
MLA Citation
Rich, JN, Zhang, M, Datto, MB, Bigner, DD, and Wang, XF. "Transforming growth factor-beta-mediated p15(INK4B) induction and growth inhibition in astrocytes is SMAD3-dependent and a pathway prominently altered in human glioma cell lines." J Biol Chem 274.49 (December 3, 1999): 35053-35058.
PMID
10574984
Source
pubmed
Published In
The Journal of biological chemistry
Volume
274
Issue
49
Publish Date
1999
Start Page
35053
End Page
35058

c-Jun enhancement of cyclic adenosine 3',5'-monophosphate response element-dependent transcription induced by transforming growth factor-beta is independent of c-Jun binding to DNA.

Transforming growth factor-beta (TGFbeta) enhances transcription from reporter genes regulated by a single consensus cAMP-response element (CRE) upon transfection into the immortalized human keratinocyte cell line, HaCaT. Whereas both CRE-binding protein (CREB) and c-Jun present in extracts of unstimulated cells can complex with a CRE in gel-shift experiments, TGFbeta treatment increases the amount of c-Jun found in the complex. Overexpression of c-Jun is sufficient to increase CRE and GAL4-CREB-dependent transcription and mimics the stimulatory effects of TGFbeta on transcription from either reporter gene. Surprisingly, although a portion of CREB in unstimulated cells is phosphorylated on the activating serine residue, Ser-133, this level of phospho-CREB is not altered by TGFbeta treatment. In fact, the CREB-dependent transcriptional effects of TGFbeta or c-Jun do not require phosphorylation of Ser-133, although CREB-binding protein (CBP) is required as evidenced by the observation that the adenoviral oncoprotein E1A can block the effects of both agents. c-Jun enhancement of CRE or GAL4-CREB-dependent transcription neither requires the DNA-binding nor N-terminal domains of c-Jun. Collectively, these results are consistent with a model in which signaling pathways initiated by TGFbeta can stimulate CREB-dependent transcription by increasing the cellular concentration of c-Jun, which participates in activation of the CBP-containing transcription complex.

Authors
Hu, PP; Harvat, BL; Hook, SS; Shen, X; Wang, XF; Means, AR
MLA Citation
Hu, PP, Harvat, BL, Hook, SS, Shen, X, Wang, XF, and Means, AR. "c-Jun enhancement of cyclic adenosine 3',5'-monophosphate response element-dependent transcription induced by transforming growth factor-beta is independent of c-Jun binding to DNA." Mol Endocrinol 13.12 (December 1999): 2039-2048.
PMID
10598580
Source
pubmed
Published In
Molecular endocrinology (Baltimore, Md.)
Volume
13
Issue
12
Publish Date
1999
Start Page
2039
End Page
2048
DOI
10.1210/mend.13.12.0405

Ras induces p21Cip1/Waf1 cyclin kinase inhibitor transcriptionally through Sp1-binding sites.

p21Cip1/Waf1 cyclin-dependent kinase inhibitor (p21) is inducible by Raf and mitogen-activated protein kinase kinase (MAPKK), but the level of regulation is unknown. We show here by conditional and transient Ras-expression models that Ras induces p21. Induction of p21 in conditionally Ras-expressing cells is posttranscriptional utilizing mitogen-activated protein kinase (MAPK) pathway. Transient, high-level Ras-expression induces transcriptional activation of p21 mediated by a GC-rich region in p21 promoter -83-54 bp relative to the transcription initiation site containing binding sites for Sp1-family transcription factors. Mutation of either Sp1-binding site 2 or 4 in this region decreases the magnitude of induction of promoter activity by Ras, but only the simultaneous mutation of both sites abolishes fully the induction. Electrophoretic mobility shift assays using an oligonucleotide corresponding to Sp1-binding site 2 indicate that both Sp1 and Sp3 transcription factors bind to this region. The results demonstrate that the central cytosolic growth regulator Ras is a potent transcriptional and posttranscriptional inducer of the nuclear growth inhibitor p21.

Authors
Kivinen, L; Tsubari, M; Haapajärvi, T; Datto, MB; Wang, XF; Laiho, M
MLA Citation
Kivinen, L, Tsubari, M, Haapajärvi, T, Datto, MB, Wang, XF, and Laiho, M. "Ras induces p21Cip1/Waf1 cyclin kinase inhibitor transcriptionally through Sp1-binding sites." Oncogene 18.46 (November 4, 1999): 6252-6261.
PMID
10597223
Source
pubmed
Published In
Oncogene: Including Oncogene Reviews
Volume
18
Issue
46
Publish Date
1999
Start Page
6252
End Page
6261
DOI
10.1038/sj.onc.1203000

Cooperation of Sp1 and p300 in the induction of the CDK inhibitor p21WAF1/CIP1 during NGF-mediated neuronal differentiation.

Addition of nerve growth factor (NGF) to PC12 cells promotes neuronal differentiation while inhibiting cell proliferation. In order to understand how NGF exerts its antimitogenic effect during differentiation, we have studied the mechanism by which this factor activates the promoter of the CDK inhibitor p21W4F1/CIP1. The minimal region of the p21 promoter required for the NGF-induction was mapped to a contiguous stretch of 10 bp located 83 bases upstream of the transcription initiation site. This GC-rich region was shown to interact specifically with the transcription factor Sp1 and the related protein Sp3, in either exponentially-growing or NGF-treated PC12 cells. The addition of NGF resulted in an accumulation of the transcriptional co-activator p300 in complexes associated with the NGF-responsive region. Transcriptional activity of Sp1, Sp3 and p300 was specifically induced by NGF in a Gal4-fusion assay, indicating that induction of p21 during neuronal differentiation may involve regulation of the activity of these factors by NGF. Furthermore, p300 was able to act as a co-activator for Sp1-mediated transcriptional activation in PC12 cells, suggesting that p300 and Sp1 may cooperate in activating p21 transcription during the withdrawal of neuronal precursors from the cell cycle. This hypothesis is supported by experiments showing that p300 and Sp1 form complexes in PC12 cells.

Authors
Billon, N; Carlisi, D; Datto, MB; van Grunsven, LA; Watt, A; Wang, XF; Rudkin, BB
MLA Citation
Billon, N, Carlisi, D, Datto, MB, van Grunsven, LA, Watt, A, Wang, XF, and Rudkin, BB. "Cooperation of Sp1 and p300 in the induction of the CDK inhibitor p21WAF1/CIP1 during NGF-mediated neuronal differentiation." Oncogene 18.18 (May 6, 1999): 2872-2882.
PMID
10362258
Source
pubmed
Published In
Oncogene: Including Oncogene Reviews
Volume
18
Issue
18
Publish Date
1999
Start Page
2872
End Page
2882
DOI
10.1038/sj.onc.1202712

Smads bind directly to the Jun family of AP-1 transcription factors.

Smad3 and Smad4 are sequence-specific DNA-binding factors that bind to their consensus DNA-binding sites in response to transforming growth factor beta (TGFbeta) and activate transcription. Recent evidence implicates Smad3 and Smad4 in the transcriptional activation of consensus AP-1 DNA-binding sites that do not interact with Smads directly. Here, we report that Smad3 and Smad4 can physically interact with AP-1 family members. In vitro binding studies demonstrate that both Smad3 and Smad4 bind all three Jun family members: JunB, cJun, and JunD. The Smad interacting region of JunB maps to a C-terminal 20-amino acid sequence that is partially conserved in cJun and JunD. We show that Smad3 and Smad4 also associate with an endogenous form of cJun that is rapidly phosphorylated in response to TGFbeta. Providing evidence for the importance of this interaction between Smad and Jun proteins, we demonstrate that Smad3 is required for the activation of concatamerized AP-1 sites in a reporter construct that has previously been characterized as unable to bind Smad proteins directly. Together, these data suggest that TGFbeta-mediated transcriptional activation through AP-1 sites may involve a regulated interaction between Smads and AP-1 transcription factors.

Authors
Liberati, NT; Datto, MB; Frederick, JP; Shen, X; Wong, C; Rougier-Chapman, EM; Wang, XF
MLA Citation
Liberati, NT, Datto, MB, Frederick, JP, Shen, X, Wong, C, Rougier-Chapman, EM, and Wang, XF. "Smads bind directly to the Jun family of AP-1 transcription factors." Proc Natl Acad Sci U S A 96.9 (April 27, 1999): 4844-4849.
PMID
10220381
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
96
Issue
9
Publish Date
1999
Start Page
4844
End Page
4849

UV radiation is a transcriptional inducer of p21(Cip1/Waf1) cyclin-kinase inhibitor in a p53-independent manner.

p53 target genes p21(Cip1/Waf1) cyclin-kinase inhibitor (p21 CKI), GADD45, bax, and cyclin G and genes affecting the redox state of the cells are implicated in p53 damage control responses. In order to attribute their functions and dependency of p53 in UV-damaged cells we undertook an analysis of UVC responses of fibroblasts derived from p53 knock-out mice. UVC radiation efficiently and rapidly inhibited DNA replication in both p53 -/- and +/+ cells. The arrest was persistent in p53 -/- fibroblasts and cells underwent apoptosis, whereas p53 +/+ cells recovered and reentered the cycle. Protein and mRNA analyses of p21 expression showed that it was induced up to sixfold with similar kinetics both in the presence and in the absence of p53. However, high doses of UV abrogated the p21 response in p53 -/- cells, whereas it was maintained in cells with normal p53. UVC radiation transcriptionally activated p21 expression as demonstrated by luciferase reporter assays using deletion constructs of the p21 promoter. The promoter assays further confirmed the independency of p53-binding sites in the activation and linked UV-responsive transcriptional regulation of p21 to two Sp1 consensus binding sites within -61 bp of the transcription initiation site. A weaker regulation was mediated by elements between -1300 to -500 bp relative to the transcription initiation site. The results suggest that in fibroblasts UVC radiation is a rapid and efficient inducer of p21 expression also in a p53-independent manner.

Authors
Haapajärvi, T; Kivinen, L; Heiskanen, A; des Bordes, C; Datto, MB; Wang, XF; Laiho, M
MLA Citation
Haapajärvi, T, Kivinen, L, Heiskanen, A, des Bordes, C, Datto, MB, Wang, XF, and Laiho, M. "UV radiation is a transcriptional inducer of p21(Cip1/Waf1) cyclin-kinase inhibitor in a p53-independent manner." Exp Cell Res 248.1 (April 10, 1999): 272-279.
PMID
10094833
Source
pubmed
Published In
Experimental Cell Research
Volume
248
Issue
1
Publish Date
1999
Start Page
272
End Page
279
DOI
10.1006/excr.1999.4403

Targeted disruption of Smad3 reveals an essential role in transforming growth factor beta-mediated signal transduction.

The Smads are a family of nine related proteins which function as signaling intermediates for the transforming growth factor beta (TGF-beta) superfamily of ligands. To discern the in vivo functions of one of these Smads, Smad3, we generated mice harboring a targeted disruption of this gene. Smad3 null mice, although smaller than wild-type littermates, are viable, survive to adulthood, and exhibit an early phenotype of forelimb malformation. To study the cellular functions of Smad3, we generated Smad3 null mouse embryonic fibroblasts (MEFs) and dermal fibroblasts. We demonstrate that null MEFs have lost the ability to form Smad-containing DNA binding complexes and are unable to induce transcription from the TGF-beta-responsive promoter construct, p3TP-lux. Using the primary dermal fibroblasts, we also demonstrate that Smad3 is integral for induction of endogenous plasminogen activator inhibitor 1. We subsequently demonstrate that Smad3 null MEFs are partially resistant to TGF-beta's antiproliferative effect, thus firmly establishing a role for Smad3 in TGF-beta-mediated growth inhibition. We next examined cells in which Smad3 is most highly expressed, specifically cells of immune origin. Although no specific developmental defect was detected in the immune system of the Smad3 null mice, a functional defect was observed in the ability of TGF-beta to inhibit the proliferation of splenocytes activated by specific stimuli. In addition, primary splenocytes display defects in TGF-beta-mediated repression of cytokine production. These data, taken together, establish a role for Smad3 in mediating the antiproliferative effects of TGF-beta and implicate Smad3 as a potential effector for TGF-beta in modulating immune system function.

Authors
Datto, MB; Frederick, JP; Pan, L; Borton, AJ; Zhuang, Y; Wang, XF
MLA Citation
Datto, MB, Frederick, JP, Pan, L, Borton, AJ, Zhuang, Y, and Wang, XF. "Targeted disruption of Smad3 reveals an essential role in transforming growth factor beta-mediated signal transduction." Mol Cell Biol 19.4 (April 1999): 2495-2504.
PMID
10082515
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
19
Issue
4
Publish Date
1999
Start Page
2495
End Page
2504

Smad3-Smad4 and AP-1 complexes synergize in transcriptional activation of the c-Jun promoter by transforming growth factor beta.

Transcriptional regulation by transforming growth factor beta (TGF-beta) is a complex process which is likely to involve cross talk between different DNA responsive elements and transcription factors to achieve maximal promoter activation and specificity. Here, we describe a concurrent requirement for two discrete responsive elements in the regulation of the c-Jun promoter, one a binding site for a Smad3-Smad4 complex and the other an AP-1 binding site. The two elements are located 120 bp apart in the proximal c-Jun promoter, and each was able to independently bind its corresponding transcription factor complex. The effects of independently mutating each of these elements were nonadditive; disruption of either sequence resulted in complete or severe reductions in TGF-beta responsiveness. This simultaneous requirement for two distinct and independent DNA binding elements suggests that Smad and AP-1 complexes function synergistically to mediate TGF-beta-induced transcriptional activation of the c-Jun promoter.

Authors
Wong, C; Rougier-Chapman, EM; Frederick, JP; Datto, MB; Liberati, NT; Li, JM; Wang, XF
MLA Citation
Wong, C, Rougier-Chapman, EM, Frederick, JP, Datto, MB, Liberati, NT, Li, JM, and Wang, XF. "Smad3-Smad4 and AP-1 complexes synergize in transcriptional activation of the c-Jun promoter by transforming growth factor beta." Mol Cell Biol 19.3 (March 1999): 1821-1830.
PMID
10022869
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
19
Issue
3
Publish Date
1999
Start Page
1821
End Page
1830

The mammalian Rad24 homologous to yeast Saccharomyces cerevisiae Rad24 and Schizosaccharomyces pombe Rad17 is involved in DNA damage checkpoint.

Cell cycle checkpoint proteins play critical roles in maintaining genomic stability and integrity to prevent the development of cancer and hereditary diseases. Here we report the isolation of a novel mouse gene encoding the protein MmRad24 [MmRad24 is the mouse homologue of HRad17, which was described recently by A. E. Parker et al. (J. Biol. Chem., 273: 18340-18346, 1998)], which shares significant sequence and structural homology with the budding yeast Rad24 and its fission yeast counterpart Rad17, both of which are required for DNA damage checkpoints. Confocal microscopy revealed that the green fluorescent protein-tagged MmRad24 protein is localized to the nucleus in living cells. Fluorescence-activated cell-sorting analysis showed that overexpression of the wild-type MmRad24 in diploid fibroblast WI-38 cells caused a significant G2 arrest of the cell cycle, whereas overexpression of a mutant MmRad24 (mutated on the nucleotide-binding site) that likely functions as a dominant-negative protein resulted in a defect in cell cycle arrest after DNA damage treatment as measured by bromodeoxyuridine pulse-chase labeling experiments. Taken together, these results suggest that the mammalian Rad24 protein may function as a critical gatekeeper in DNA damage checkpoint control.

Authors
Bao, S; Shen, X; Shen, K; Liu, Y; Wang, XF
MLA Citation
Bao, S, Shen, X, Shen, K, Liu, Y, and Wang, XF. "The mammalian Rad24 homologous to yeast Saccharomyces cerevisiae Rad24 and Schizosaccharomyces pombe Rad17 is involved in DNA damage checkpoint." Cell Growth Differ 9.12 (December 1998): 961-967.
PMID
9869296
Source
pubmed
Published In
Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research
Volume
9
Issue
12
Publish Date
1998
Start Page
961
End Page
967

Molecular mechanisms of transforming growth factor-beta signaling.

Authors
Hu, PP; Datto, MB; Wang, XF
MLA Citation
Hu, PP, Datto, MB, and Wang, XF. "Molecular mechanisms of transforming growth factor-beta signaling." Endocr Rev 19.3 (June 1998): 349-363. (Review)
PMID
9626558
Source
pubmed
Published In
Endocrine reviews
Volume
19
Issue
3
Publish Date
1998
Start Page
349
End Page
363
DOI
10.1210/edrv.19.3.0333

Sp1, but not Sp3, functions to mediate promoter activation by TGF-beta through canonical Sp1 binding sites.

Transforming growth factor beta (TGF-beta) causes growth arrest at the G1 phase of the cell cycle in most cell types. Both the cyclin dependent kinase inhibitor p15(INK4B) and p21(Cip1/WAF1) genes have been found to be induced by TGF-beta in human keratinocyte HaCaT cells. Analyses of the human p15 and p21 promoters have led to the identification of GC-rich sequences capable of binding to Sp1 transcription factors as necessary elements for the TGF-beta induction of both promoters. We report here that canonical Sp1 binding sites derived from the SV40 21 bp repeat could also support promoter induction by TGF-beta when placed upstream of a minimal luciferase reporter construct containing only the TATA and Inr elements. Gel retardation assays identified Sp1, Sp3 and DeltaSp3 as major factors binding to the canonical Sp1 sites in HaCaT cells and that TGF-beta treatment did not change their binding activities over a 24 h period. More importantly, GAL4-Sp1, but not GAL4-Sp3, chimeric protein supported TGF-beta mediated gene induction from a luciferase reporter construct driven by five GAL4 DNA binding sites. Our results suggest that Sp1 binding site can function as a distinct TGF-beta responsive element for TGF-beta mediated promoter expression and Sp1 per se can mediate this response.

Authors
Li, JM; Datto, MB; Shen, X; Hu, PP; Yu, Y; Wang, XF
MLA Citation
Li, JM, Datto, MB, Shen, X, Hu, PP, Yu, Y, and Wang, XF. "Sp1, but not Sp3, functions to mediate promoter activation by TGF-beta through canonical Sp1 binding sites." Nucleic Acids Res 26.10 (May 15, 1998): 2449-2456.
PMID
9580699
Source
pubmed
Published In
Nucleic Acids Research
Volume
26
Issue
10
Publish Date
1998
Start Page
2449
End Page
2456

FKBP12 is not required for the modulation of transforming growth factor beta receptor I signaling activity in embryonic fibroblasts and thymocytes.

Transforming growth factor beta (TGF-beta) signals through a heteromeric complex of type I and type II transmembrane serine-threonine kinases. Recent evidence suggests that the immunophilin FKBP12 modulates the activity of the type I receptor, based on data that immunosuppressive drugs that disrupt FKBP12 binding to the type I receptor enhance TGF-beta signaling in mink lung epithelial cells, and overexpression of FKBP12 inhibits type I receptor phosphorylation by the type II receptor. To determine the physiological relevance of the FKBP12-TGF-beta receptor I interaction, we investigated whether disruption of this interaction affects TGF-beta-signaling in primary mouse embryo fibroblasts and thymocytes. We found that the addition of excess drugs had no effect on either TGF-beta-mediated transcriptional responses or growth inhibition. Dose-response curves for TGF-beta-mediated signaling in primary fibroblasts and thymocytes isolated from either wild-type or FKBP12-deficient mice were identical. Taken together, our results indicate that FKBP12 does not play a unique physiological role in TGF-beta signaling in primary fibroblasts and thymocytes.

Authors
Bassing, CH; Shou, W; Muir, S; Heitman, J; Matzuk, MM; Wang, XF
MLA Citation
Bassing, CH, Shou, W, Muir, S, Heitman, J, Matzuk, MM, and Wang, XF. "FKBP12 is not required for the modulation of transforming growth factor beta receptor I signaling activity in embryonic fibroblasts and thymocytes." Cell Growth Differ 9.3 (March 1998): 223-228.
PMID
9543388
Source
pubmed
Published In
Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research
Volume
9
Issue
3
Publish Date
1998
Start Page
223
End Page
228

Transforming growth factor beta stimulates the human immunodeficiency virus 1 enhancer and requires NF-kappaB activity.

Transforming growth factor beta (TGF-beta) is the prototype of a large superfamily of signaling molecules involved in the regulation of cell growth and differentiation. In certain patients infected with human immunodeficiency virus type 1 (HIV-1), increased levels of TGF-beta promoted the production of virus and also impaired the host immune system. In an effort to understand the signaling events linking TGF-beta action and HIV production, we show here that TGF-beta can stimulate transcription from the HIV-1 long terminal repeat (LTR) promoter through NF-kappaB binding sites in both HaCaT and 300.19 pre-B cells. When introduced into a minimal promoter, NF-kappaB binding sites supported nearly 30-fold activation from the luciferase reporter upon TGF-beta treatment. Electrophoretic mobility shift assay indicated that a major factor binding to the NF-kappaB site is the p50-p65 heterodimeric NF-kappaB in HaCaT cells. Coexpression of Gal4-p65 chimeric proteins supported TGF-beta ligand-dependent gene expression from a luciferase reporter gene driven by Gal4 DNA binding sites. NF-kappaB activity present in HaCaT cells was not affected by TGF-beta treatment as judged by the unchanged DNA binding activity and concentrations of p50 and p65 proteins. Consistently, steady-state levels of IkappaB alpha and IkappaB beta proteins were not changed by TGF-beta treatment. Our results demonstrate that TGF-beta is able to stimulate transcription from the HIV-1 LTR promoter by activating NF-kappaB through a mechanism distinct from the classic NF-kappaB activation mechanism involving the degradation of IkappaB proteins.

Authors
Li, JM; Shen, X; Hu, PP; Wang, XF
MLA Citation
Li, JM, Shen, X, Hu, PP, and Wang, XF. "Transforming growth factor beta stimulates the human immunodeficiency virus 1 enhancer and requires NF-kappaB activity." Mol Cell Biol 18.1 (January 1998): 110-121.
PMID
9418859
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
18
Issue
1
Publish Date
1998
Start Page
110
End Page
121

TGF-β-induced phosphorylation of Smad3 regulates its interaction with coactivator p300/CREB-binding protein

Smads are intermediate effector proteins that transduce the TGF-β signal from the plasma membrane to the nucleus, where they participate in transactivation of downstream target genes. We have shown previously that coactivators p300/CREB-binding protein are involved in TGF-β-mediated transactivation of two Cdk inhibitor genes, p21 and p15. Here we examined the possibility that Smads function to regulate transcription by directly interacting with p300/CREB-binding protein. We show that Smad3 can interact with a C-terminal fragment of p300 in a temporal and phosphorylation- dependent manner. TGF-β-mediated phosphorylation of Smad3 potentiates the association between Smad3 and p300, likely because of an induced conformational change that removes the autoinhibitory interaction between the N- and C-terminal domains of Smad3. Consistent with a role for p300 in the transcription regulation of multiple genes, overexpression of a Smad3 C- terminal fragment causes a general squelching effect on multiple TGF-β- responsive reporter constructs. The adenoviral oncoprotein E1A can partially block Smad-dependent transcriptional activation by directly competing for binding to p300. Taken together, these findings define a new role for phosphorylation of Smad3: in addition to facilitating complex formation with Smad4 and promoting nuclear translocation, the phosphorylation-induced conformational change of Smad3 modulates its interaction with coactivators, leading to transcriptional regulation.

Authors
Shen, X; Hu, PP-C; Liberati, NT; Datto, MB; Frederick, JP; Wang, X-F
MLA Citation
Shen, X, Hu, PP-C, Liberati, NT, Datto, MB, Frederick, JP, and Wang, X-F. "TGF-β-induced phosphorylation of Smad3 regulates its interaction with coactivator p300/CREB-binding protein." Molecular Biology of the Cell 9.12 (1998): 3309-3319.
Source
scival
Published In
Molecular Biology of the Cell
Volume
9
Issue
12
Publish Date
1998
Start Page
3309
End Page
3319

Inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase pathway induces p53-independent transcriptional regulation of p21(WAF1/CIP1) in human prostate carcinoma cells

Progression through the cell cycle is controlled by the induction of cyclins and the activation of cognate cyclin-dependent kinases. The 3- hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor lovastatin induces growth arrest and cell death in certain cancer cell types. We have pursued the mechanism of growth arrest in PC-3-M cells, a p53-null human prostate carcinoma cell line. Lovastatin treatment increased protein and mRNA levels of the cyclin-dependent kinase inhibitor p21(WAFI/CIP1), increased binding of p21 with Cdk2, markedly inhibited cyclin E- and Cdk2-associated phosphorylation of histone H1 or GST-retinoblastoma protein, enhanced binding of the retinoblastoma protein to the transcription factor E2F-1 in vivo, and induced the activation of a p21 promoter reporter construct. By using p21 promoter deletion constructs, the lovastatin-responsive element was mapped to a region between -93 and -64 relative to the transcription start site. Promoter mutation analysis indicated that the lovastatin-responsive site coincided with the previously identified transforming growth factor-β- responsive element. These data indicate that in human prostate carcinoma cells an inhibitor of the HMG-CoA reductase pathway can circumvent the loss of wild-type p53 function and induce critical downstream regulatory events leading to transcriptional activation of p21.

Authors
Lee, SJ; Ha, MJ; Lee, J; Nguyen, P; Choi, YH; Pirnia, F; Kang, W-K; Wang, X-F; Kim, S-J; Trepel, JB
MLA Citation
Lee, SJ, Ha, MJ, Lee, J, Nguyen, P, Choi, YH, Pirnia, F, Kang, W-K, Wang, X-F, Kim, S-J, and Trepel, JB. "Inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase pathway induces p53-independent transcriptional regulation of p21(WAF1/CIP1) in human prostate carcinoma cells." Journal of Biological Chemistry 273.17 (1998): 10618-10623.
PMID
9553123
Source
scival
Published In
The Journal of biological chemistry
Volume
273
Issue
17
Publish Date
1998
Start Page
10618
End Page
10623
DOI
10.1074/jbc.273.17.10618

Quantitive estimates of outcrossing rates in a natural population of Sagittaria potamogetifolia

The outcrossing rates of two subpopulations in a population of Sagittaria potamogetifolia were estimated by sampling from natural habitats and using single genetic marker locus. The value of subpopulation I (t̄̂I = (81. 9 ± 24.1)%) is remarkably higher than that of subpopulation II (t̄̂I = (50. 0 ± 24. 5)%), while subpopulation II had a higher density. For the monoecius spicies S. potamogetifolia, a rate of selfing in a population should be due to the pollination between different inflorescences of same plant, and the levels of selfing/outcrossing in populations should be dependent on the frequency of the individuals with more than two inflorescences.

Authors
Wang, X; Chen, J
MLA Citation
Wang, X, and Chen, J. "Quantitive estimates of outcrossing rates in a natural population of Sagittaria potamogetifolia." Wuhan Daxue Xuebao/Journal of Wuhan University 44.2 (1998): X22-220.
Source
scival
Published In
Wuhan Daxue Xuebao/Journal of Wuhan University
Volume
44
Issue
2
Publish Date
1998
Start Page
X22
End Page
220

Tumor suppressor Smad4 is a transforming growth factor beta-inducible DNA binding protein.

Members of the Smad family of proteins are thought to play important roles in transforming growth factor beta (TGF-beta)-mediated signal transduction. In response to TGF-beta, specific Smads become inducibly phosphorylated, form heteromers with Smad4, and undergo nuclear accumulation. In addition, overexpression of specific Smad combinations can mimic the transcriptional effect of TGF-beta on both the plasminogen activator inhibitor 1 (PAI-1) promoter and the reporter construct p3TP-Lux. Although these data suggest a role for Smads in regulating transcription, the precise nuclear function of these heteromeric Smad complexes remains largely unknown. Here we show that in Mv1Lu cells Smad3 and Smad4 form a TGF-beta-induced, phosphorylation-dependent, DNA binding complex that specifically recognizes a bipartite binding site within p3TP-Lux. Furthermore, we demonstrate that Smad4 itself is a DNA binding protein which recognizes the same sequence. Interestingly, mutations which eliminate the Smad DNA binding site do not interfere with either TGF-beta-dependent transcriptional activation or activation by Smad3/Smad4 cooverexpression. In contrast, mutation of adjacent AP1 sites within this context eliminates both TGF-beta-dependent transcriptional activation and activation in response to Smad3/Smad4 cooverexpression. Furthermore, concatemerized AP1 sites, in isolation, are activated by Smad3/Smad4 cooverexpression and, to a certain extent, by TGF-beta. Taken together, these data suggest that the Smad3/Smad4 complex has at least two separable nuclear functions: it forms a rapid, yet transient sequence-specific DNA binding complex, and it potentiates AP1-dependent transcriptional activation.

Authors
Yingling, JM; Datto, MB; Wong, C; Frederick, JP; Liberati, NT; Wang, XF
MLA Citation
Yingling, JM, Datto, MB, Wong, C, Frederick, JP, Liberati, NT, and Wang, XF. "Tumor suppressor Smad4 is a transforming growth factor beta-inducible DNA binding protein." Mol Cell Biol 17.12 (December 1997): 7019-7028.
PMID
9372933
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
17
Issue
12
Publish Date
1997
Start Page
7019
End Page
7028

E2F4-RB and E2F4-p107 complexes suppress gene expression by transforming growth factor beta through E2F binding sites.

Transforming growth factor beta (TGF-beta) causes growth arrest in most cell types. TGF-beta induces hypophosphorylation of retinoblastoma susceptibility gene 1 product (RB), which sequesters E2F factors needed for progression into S phase of the cell cycle, thereby leading to cell cycle arrest at G1. It is possible, however, that the E2F-RB complex induced by TGF-beta may bind to E2F sites and suppress expression of specific genes whose promoters contain E2F binding sites. We show here that TGF-beta treatment of HaCaT cells induced the formation of E2F4-RB and E2F4-p107 complexes, which are capable of binding to E2F sites. Disruption of their binding to DNA with mutation in the E2F sites did not change the expression from promoters of E2F1, B-myb, or HsORC1 genes in cycling HaCaT cells. However, the same mutation stimulated 5- to 6-fold higher expression from all three promoters in cells treated with TGF-beta. These results suggest that E2F binding sites play an essential role in the transcription repression of these genes under TGF-beta treatment. Consistent with their repression of TGF-beta-induced gene expression, introduction of E2F sites into the promoter of cyclin-dependent kinase inhibitor p15(INK4B) gene effectively inhibited its induction by TGF-beta. Experiments utilizing Gal4-RB and Gal4-p107 chimeric constructs demonstrated that either RB or p107 could directly repress TGF-beta induction of p15(INK4B) gene when tethered to p15(INK4B) promoter through Gal4 DNA binding sites. Therefore, E2F functions to bring RB and p107 to E2F sites and represses gene expression by TGF-beta. These results define a specific function for E2F4-RB and E2F4-p107 complexes in gene repression under TGF-beta treatment, which may constitute an integral part of the TGF-beta-induced growth arrest program.

Authors
Li, JM; Hu, PP; Shen, X; Yu, Y; Wang, XF
MLA Citation
Li, JM, Hu, PP, Shen, X, Yu, Y, and Wang, XF. "E2F4-RB and E2F4-p107 complexes suppress gene expression by transforming growth factor beta through E2F binding sites." Proc Natl Acad Sci U S A 94.10 (May 13, 1997): 4948-4953.
PMID
9144170
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
94
Issue
10
Publish Date
1997
Start Page
4948
End Page
4953

The viral oncoprotein E1A blocks transforming growth factor beta-mediated induction of p21/WAF1/Cip1 and p15/INK4B.

The adenovirus early gene product E1A is a potent stimulator of cellular proliferation, which when overexpressed can overcome the growth-inhibitory effects of the polypeptide hormone transforming growth factor beta (TGF-beta). The ability of TGF-beta to arrest cell growth in G1 correlates with the transcriptional induction of the cyclin-dependent kinase inhibitors, p15/INK4B and p21/WAF1/Cip1; an inhibition of the G1 cyclin-Cdk complexes; and a maintenance of the retinoblastoma susceptibility gene product, Rb, in a hypophosphorylated state. The ability of E1A to overcome TGF-beta-mediated growth inhibition derives, in part, from its ability to sequester Rb and Rb family members. We report here that E1A also acts upstream of Rb by blocking the TGF-beta-mediated induction of p15 and p21. Consistent with these findings, E1A expression also blocks the ability of TGF-beta to inhibit Cdk2 kinase activity, as well as its ability to hold Rb in a hypophosphorylated state. The effect of E1A on the induction of p15 and p21 is independent of E1A's Rb binding activity. The E1A-mediated decrease in p15 levels is primarily the result of a block at the level of transcriptional activation by TGF-beta. This effect is dependent on E1A's ability to bind p300, one of E1A's target proteins. Thus, the ability of E1A to affect p15 and p21 expression represents an additional possible mechanism by which E1A can circumvent the negative regulation of cell cycle progression.

Authors
Datto, MB; Hu, PP; Kowalik, TF; Yingling, J; Wang, XF
MLA Citation
Datto, MB, Hu, PP, Kowalik, TF, Yingling, J, and Wang, XF. "The viral oncoprotein E1A blocks transforming growth factor beta-mediated induction of p21/WAF1/Cip1 and p15/INK4B." Mol Cell Biol 17.4 (April 1997): 2030-2037.
PMID
9121451
Source
pubmed
Published In
Molecular and Cellular Biology
Volume
17
Issue
4
Publish Date
1997
Start Page
2030
End Page
2037

Expression of mRNAs coding for the transforming growth factor-beta receptors in brain regions of euthyroid and hypothyroid neonatal rats and in adult brain.

The TGF-beta family of peptides has been postulated to play a role in control of the cell cycle but also may act in the developing brain to influence neuronal differentiation and survival. Because reception of TGF-beta signals requires the simultaneous expression of all three known receptor subtypes, we examined two neonatal rat brain regions in which neurogenesis has been largely completed. mRNA coding for all three receptors was detectable in both the forebrain and brainstem but only the type II receptor in brainstem showed a difference from adult levels of expression. Animals given perinatal PTU treatment to achieve congenital cretinism did not show significant differences in expression of any of the receptor subtypes in either of the regions, despite the fact that the treatment is known to cause anomalies of neuronal differentiation. These results indicate that regions in which neurons are undergoing axonogenesis and synaptogenesis rather than neurogenesis, nevertheless express the mRNAs coding for TGF-beta receptors and are thus likely to be receptive to trophic signals mediated through TGF-beta. However, synthesis and release of TGF-beta, rather than receptor expression per se, is more likely to be the major point for regulation of signaling. The potential roles of TGF-beta in developmental events outside of the cell cycle, such as synaptogenesis and apoptosis, need to be examined.

Authors
Slotkin, TA; Wang, XF; Symonds, HS; Seidler, FJ
MLA Citation
Slotkin, TA, Wang, XF, Symonds, HS, and Seidler, FJ. "Expression of mRNAs coding for the transforming growth factor-beta receptors in brain regions of euthyroid and hypothyroid neonatal rats and in adult brain." Brain Res Dev Brain Res 99.1 (March 17, 1997): 61-65.
PMID
9088566
Source
pubmed
Published In
Developmental Brain Research
Volume
99
Issue
1
Publish Date
1997
Start Page
61
End Page
65

Smad5 induces ventral fates in Xenopus embryo

The Smad proteins have been implicated in the intracellular signaling of transforming growth factor-β (TGF-β) ligands. Here we describe the function of Smad5 in early Xenopus development. Misexpression of Smad5 in the embryo causes ventralization and induces ventral mesoderm. Moreover, Smad5 induces epidermis in dissociated ectoderm cells which would otherwise form neural tissue. Both of these activities require Smad4 (DPC4) activity. We propose that Smad5 acts downstream of the BMP4 signaling pathway in Xenopus embryos and directs the formation of ventral mesoderm and epidermis.

Authors
Suzuki, A; Chang, C; Yingling, JM; Wang, X-F; Hemmati-Brivanlou, A
MLA Citation
Suzuki, A, Chang, C, Yingling, JM, Wang, X-F, and Hemmati-Brivanlou, A. "Smad5 induces ventral fates in Xenopus embryo." Developmental Biology 184.2 (1997): 402-405.
PMID
9133445
Source
scival
Published In
Developmental Biology
Volume
184
Issue
2
Publish Date
1997
Start Page
402
End Page
405
DOI
10.1006/dbio.1997.8548

Expression of transforming growth factor β (TGFβ) type III receptor restores autocrine TGFβ1 activity in human breast cancer MCF-7 cells

While transforming growth factor β (TGFβ) type III receptor (RIII) is known to increase TGFβ1 binding to its type II receptor (RII), the significance of this phenomenon is not known. We used human breast cancer MCF-7 cells to study the role of RIII in regulating autocrine TGFβ1 activity because they express very little RIII and no detectable autocrine TGFβ activity. A tetracycline-repressible RIII expression vector was stably transfected into this cell line. Expression of RIII increased TGFβ1 binding to TGFβ type I receptor (RI) as well as RII. Treatment with tetracycline suppressed RIII expression and abolished TGFβ1 binding to RI and RII. Growth of RIII-transfected cells was reduced by 40% when plated at low density on plastic. This reduction was reversed by tetracycline treatment and was partially reversed by treatment with a TGFβ1 neutralizing antibody. The activity of a TGFβ1-responsive promoter construct when transiently transfected was more than 3-fold higher in the RIII-transfected cells than in the control cells. Treating the cells with tetracycline or the TGFβ1 neutralizing antibody also significantly attenuated the increased promoter activity. These results suggest that expression of RIII restored autocrine TGFβ1 activity in MCF-7 cells. The RIII-transfected cells were also much less clonogenic in soft agarose than the control cells indicating a reversion of progression. Thus, RIII may be essential for an optimal level of the autocrine TGFβ activity in some cells, especially in the transformed cells with reduced RII expression.

Authors
Chen, C; Wang, X-F; Sun, L
MLA Citation
Chen, C, Wang, X-F, and Sun, L. "Expression of transforming growth factor β (TGFβ) type III receptor restores autocrine TGFβ1 activity in human breast cancer MCF-7 cells." Journal of Biological Chemistry 272.19 (1997): 12862-12867.
PMID
9139748
Source
scival
Published In
The Journal of biological chemistry
Volume
272
Issue
19
Publish Date
1997
Start Page
12862
End Page
12867
DOI
10.1074/jbc.272.19.12862

The TGFβ receptors and signaling pathways

Authors
Datto, MB; Bassing, CH; Wang, X-F
MLA Citation
Datto, MB, Bassing, CH, and Wang, X-F. "The TGFβ receptors and signaling pathways." Growth Factors and Cytokines in Health and Disease 1.C (1996): 395-432.
Source
scival
Published In
Growth Factors and Cytokines in Health and Disease
Volume
1
Issue
C
Publish Date
1996
Start Page
395
End Page
432
DOI
10.1016/S1874-5687(96)80017-6

Nomenclature: vertebrate mediators of TGFbeta family signals.

Authors
Derynck, R; Gelbart, WM; Harland, RM; Heldin, CH; Kern, SE; Massagué, J; Melton, DA; Mlodzik, M; Padgett, RW; Roberts, AB; Smith, J; Thomsen, GH; Vogelstein, B; Wang, XF
MLA Citation
Derynck, R, Gelbart, WM, Harland, RM, Heldin, CH, Kern, SE, Massagué, J, Melton, DA, Mlodzik, M, Padgett, RW, Roberts, AB, Smith, J, Thomsen, GH, Vogelstein, B, and Wang, XF. "Nomenclature: vertebrate mediators of TGFbeta family signals." Cell 87.2 (1996): 173--.
PMID
8861901
Source
scival
Published In
Cell
Volume
87
Issue
2
Publish Date
1996
Start Page
173-

Mammalian dwarfins are phosphorylated in response to transforming growth factor β and are implicated in control of cell growth

The dwarfin protein family has been genetically implicated in transforming growth factor β (TGF-β)like signaling pathways in Drosophila and Caenorhabditis elegans. To investigate the role of these proteins in mammalian signaling pathways, we have isolated and studied two murine dwarfins, dwarfin-A and dwarfin-C. Using antibodies against dwarfin-A and dwarfin-C, we show that these two dwarfins and an immunogenically related protein, presumably also a dwarfin, are phosphorylated in a time- and dose- dependent manner in response to TGF-β. Bone morphogenetic protein 2, a TGF- β superfamily ligand, induces phosphorylation of only the related dwarfin protein. Thus, TGF-β superfamily members may use overlapping yet distinct dwarfins to mediate their intracellular signals. Furthermore, transient overexpression of either dwarfin-A or dwarfin-C causes growth arrest, implicating the dwarfins in growth regulation. This work provides strong biochemical and preliminary functional evidence that dwarfin-A and dwarfin-C represent prototypic members of a family of mammalian proteins that may serve as mediators of signaling pathways for TGF-β superfamily members.

Authors
Yingling, JM; Das, P; Savage, C; Zhang, M; Padgett, RW; Wang, X-F
MLA Citation
Yingling, JM, Das, P, Savage, C, Zhang, M, Padgett, RW, and Wang, X-F. "Mammalian dwarfins are phosphorylated in response to transforming growth factor β and are implicated in control of cell growth." Proceedings of the National Academy of Sciences of the United States of America 93.17 (1996): 8940-8944.
PMID
8799132
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
93
Issue
17
Publish Date
1996
Start Page
8940
End Page
8944
DOI
10.1073/pnas.93.17.8940

Reduced expression of transforming growth factor β type I receptor contributes to the malignancy of human colon carcinoma cells

Transforming growth factor β (TGFβ) type I (RI) and type II (RII) receptors are essential for TGFβ signal transduction. A human colon carcinoma cell line, designated GEO, is marginally responsive to TGFβ and expresses a low level of RI mRNA relative to colon carcinoma cells, which are highly responsive to TGFβ. Hence, the role of RI as a limiting factor for TGFβ sensitivity and the contribution of low RI levels to the malignant phenotype of GEO cells were examined. Stable transfection of a tetracycline- regulatable rat RI cDNA increased TGFβ1 binding to RI and resulted in increased growth inhibition by exogenous TGβ1. In contrast, although stable transfection of an RII expression vector into the same GEO cells increased TGFβ1 binding to RII, growth inhibition by exogenous TGFβ1 was not altered. This indicated that the low level of RI is a limiting factor for the growth-inhibitory effects of TGFβ in GEO cells. RI-transfected cells were growth-arrested at a lower saturation density than GEO control cells. They also showed reduced growth and clonogenicity in plating efficiency and soft agarose assays, whereas RII-transfected cells did not show any differences from the NEO control cells in these assays. Tetracycline repressed RI expression in transfected cells and reversed the reduction in plating efficiency of RI-transfected clones, confirming that growth effects were due to increased RI expression in transfected cells. TGFβ1 neutralizing antibody stimulated the proliferation of RI-transfected cells but had little effect on GEO control cells, indicating that increased autocrine-negative TGFβ activity also resulted from increased RI expression. Tumorigenicity in athymic nude mice was significantly delayed in RI-transfected cells. These results indicate that low RI expression can be a limiting factor for response to exogenous TGFβ, as well as TGFβ autocrine-negative activity, and that reduction of RI expression can contribute to malignant progression.

Authors
Wang, J; Han, W; Zborowska, E; Liang, J; Wang, X; Willson, JKV; Sun, L; Brattain, MG
MLA Citation
Wang, J, Han, W, Zborowska, E, Liang, J, Wang, X, Willson, JKV, Sun, L, and Brattain, MG. "Reduced expression of transforming growth factor β type I receptor contributes to the malignancy of human colon carcinoma cells." Journal of Biological Chemistry 271.29 (1996): 17366-17371.
PMID
8663343
Source
scival
Published In
The Journal of biological chemistry
Volume
271
Issue
29
Publish Date
1996
Start Page
17366
End Page
17371
DOI
10.1074/jbc.271.29.17366

Functional analysis of the transforming growth factor beta responsive elements in the WAF1/Cip1/p21 promoter.

The transforming growth factor beta s (TGF-beta s) are a group of multifunctional growth factors that inhibit cell cycle progression in many cell types. The TGF-beta-induced cell cycle arrest has been partially attributed to the regulatory effects of TGF-beta on both the levels and activities of the G1 cyclins and their cyclin-dependent kinase partners. The ability of TGF-beta to inhibit the activity of these kinase complexes derives in part from its regulatory effects on the cyclin-dependent kinase inhibitors, p21/WAF1/Cip1, p27Kip1, and p15. Upon treatment of cells with TGF-beta, these three inhibitors bind to and block the activities of specific cyclin-cyclin-dependent kinase complexes to cause cell cycle arrest. Little is known, however, on the mechanism through which TGF-beta activates these cyclin-dependent kinase inhibitors. In the case of p21, TGF-beta treatment leads to an increase in p21 mRNA. This increase in p21 mRNA is partly due to transcriptional activation of the p21 promoter by TGF-beta. To further define the signaling pathways through which TGF-beta induces p21, we have performed a detailed functional analysis on the p21 promoter. Through both deletion and mutation analysis of the p21 promoter, we have defined a 10-base pair sequence that is required for the activation of the p21 promoter by TGF-beta. In addition, this sequence is sufficient to drive TGF-beta-mediated transcription from a previously nonresponsive promoter. Preliminary gel shift assays demonstrate that this TGF-beta responsive element binds specifically to several proteins in vitro. Two of these proteins are the transcription factors Sp-1 and Sp-3. These studies represent the initial steps toward defining the signaling pathways involved in TGF-beta-mediated transcriptional activation of p21.

Authors
Datto, MB; Yu, Y; Wang, XF
MLA Citation
Datto, MB, Yu, Y, and Wang, XF. "Functional analysis of the transforming growth factor beta responsive elements in the WAF1/Cip1/p21 promoter." J Biol Chem 270.48 (December 1, 1995): 28623-28628.
PMID
7499379
Source
pubmed
Published In
The Journal of biological chemistry
Volume
270
Issue
48
Publish Date
1995
Start Page
28623
End Page
28628

Transforming growth factor beta activates the promoter of cyclin-dependent kinase inhibitor p15INK4B through an Sp1 consensus site.

Transforming growth factor beta (TGF-beta) causes growth arrest in the G1 phase in many cell types. One probable pathway for this growth inhibition is through the TGF-beta-mediated up-regulation of the cyclin-dependent kinase (CDK) inhibitor p15INK4B, which specifically inhibits the enzymatic activities of CDK4 and CDK6. An active cyclin D-CDK4/6 complex is required for pRb phosphorylation to allow the cell cycle to progress from G1 to S phase. To study the molecular mechanism of the p15INK4B induction by TGF-beta, we isolated a 780-base pair promoter sequence of the human p15 gene and inserted this fragment upstream of a luciferase reporter gene. When this construct was transiently transfected into HaCaT cells, luciferase activity was induced more than 10-fold upon TGF-beta treatment, indicating that the induction of p15INK4B expression by TGF-beta is partly exerted at the transcription level. Promoter deletion analysis revealed that the sequence from -110 to -40 relative to the transcription start site is capable of conferring the 10-fold induction by TGF-beta. Within this region there are three Sp1 consensus sites. Mutation of one of these sites, GGGGCGGAG, substantially reduced both the induction by TGF-beta and the basal promoter activity, whereas mutations in the other two Sp1 sites and the spacer sequences had little effect. In addition, gel mobility shift assay indicates that the transcription factors Sp1 and Sp3 bind to this Sp1 site. Taken together, these data suggest that a specific Sp1 consensus site is involved in the mediation of TGF-beta induction as well as the basal promoter activity of the p15 gene and that Sp1 and Sp3 transcription factors might be involved in this regulation.

Authors
Li, JM; Nichols, MA; Chandrasekharan, S; Xiong, Y; Wang, XF
MLA Citation
Li, JM, Nichols, MA, Chandrasekharan, S, Xiong, Y, and Wang, XF. "Transforming growth factor beta activates the promoter of cyclin-dependent kinase inhibitor p15INK4B through an Sp1 consensus site." J Biol Chem 270.45 (November 10, 1995): 26750-26753.
PMID
7592908
Source
pubmed
Published In
The Journal of biological chemistry
Volume
270
Issue
45
Publish Date
1995
Start Page
26750
End Page
26753

Transforming growth factor beta induces the cyclin-dependent kinase inhibitor p21 through a p53-independent mechanism.

The transforming growth factor beta s (TGF-beta s) are a group of multifunctional growth factors which inhibit cell cycle progression in many cell types. The TGF-beta-induced cell cycle arrest has been partially attributed to the regulatory effects of TGF-beta on both the levels and the activities of the G1 cyclins and their kinase partners. The activities of these kinases are negatively regulated by a number of small proteins, p21 (WAF1, Cip1), p27Kip1, p16, and p15INK4B, that physically associate with cyclins, cyclin-dependent kinases, or cyclin-Cdk complexes. p21 has been previously shown to be transcriptionally induced by DNA damage through p53 as a mediator. We demonstrate that TGF-beta also causes a rapid transcriptional induction of p21, suggesting that p21 can respond to both intracellular and extracellular signals for cell cycle arrest. In contrast to DNA damage, however, induction of p21 by TGF-beta is not dependent on wild-type p53. The cell line studied in these experiments, HaCaT, contains two mutant alleles of p53, which are unable to activate transcription from the p21 promoter when overexpressed. In addition, TGF-beta and p53 act through distinct elements in the p21 promoter. Taken together, these findings suggest that TGF-beta can induce p21 through a p53-independent pathway. Previous findings have implicated p27Kip1 and p15INK2B as effectors mediating the TGF-beta growth inhibitory effect. These results demonstrate that a single extracellular antiproliferative signal, TGF-beta, can act through multiple signaling pathways to elicit a growth arrest response.

Authors
Datto, MB; Li, Y; Panus, JF; Howe, DJ; Xiong, Y; Wang, XF
MLA Citation
Datto, MB, Li, Y, Panus, JF, Howe, DJ, Xiong, Y, and Wang, XF. "Transforming growth factor beta induces the cyclin-dependent kinase inhibitor p21 through a p53-independent mechanism." Proc Natl Acad Sci U S A 92.12 (June 6, 1995): 5545-5549.
PMID
7777546
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
92
Issue
12
Publish Date
1995
Start Page
5545
End Page
5549

Expression of the E2F1 transcription factor overcomes type beta transforming growth factor-mediated growth suppression.

Inhibition of cell growth by type beta transforming growth factor (TGF-beta) occurs in mid-G1 and is associated with decreased G1 cyclin-dependent kinase activity and maintenance of the retinoblastoma tumor suppressor protein Rb in an underphosphorylated, growth-suppressive state. A variety of recent experiments suggest that a functional target of Rb is the E2F transcription factor. In addition, the growth-suppressive effects of TGF-beta can be overcome by expression of viral oncogene products that dissociate E2F from Rb and Rb-related polypeptides. These results suggest the possibility that control of E2F may be a downstream event of TGF-beta action. Consistent with that possibility is the observation that E2F1 RNA levels are drastically reduced in TGF-beta-treated cells. We have also used a recombinant adenovirus containing the human E2F1 gene to overexpress the E2F1 product in mink lung epithelial cells that were growth arrested with TGF-beta. We find that overexpression of E2F1 can overcome the TGF-beta-mediated effect as measured by the activation of cellular DNA synthesis. These results suggest that a likely downstream target for the cyclin-dependent kinases, which are controlled by TGF-beta, is the activation of E2F.

Authors
Schwarz, JK; Bassing, CH; Kovesdi, I; Datto, MB; Blazing, M; George, S; Wang, XF; Nevins, JR
MLA Citation
Schwarz, JK, Bassing, CH, Kovesdi, I, Datto, MB, Blazing, M, George, S, Wang, XF, and Nevins, JR. "Expression of the E2F1 transcription factor overcomes type beta transforming growth factor-mediated growth suppression." Proc Natl Acad Sci U S A 92.2 (January 17, 1995): 483-487.
PMID
7831315
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
92
Issue
2
Publish Date
1995
Start Page
483
End Page
487

Restricted expression of type-II TGFβ receptor in murine embryonic development suggests a central role in tissue modeling and CNS patterning

The type-II TGFβ receptor mediates many of the biological responses to TGFβ. An examination of the expression of the type-II TGFβ receptor during mouse embryogenesis therefore provides specific information about the role of TGFβ during embryogenesis than has been available to date. We have isolated the genomic murine homologue of the human type-II TGFβ receptor corresponding to exon 2. The murine and human sequences show a high degree of homology. Using the murine probe, we found that type-II TGFβ receptor expression is regulated in both a spatial and a temporal fashion by using in situ hybridization and ribonuclease protection assays. Type-II TGFβ receptor expression is localized to the mesenchyme during critical interactions with adjacent epithelium such as developing hair follicles, whisker follicles and tooth anlage. In the central nervous system, type-II TGFβ receptor expression is highly restricted to the floor plate. Strong expression is also detected in migrating neural crest cells, meninges, and choroid plexus. Specific mesenchymal localization of type-II TGFβ receptor is also observed in lung, kidney, intestine, stomach, and bladder. The restricted expression of type-II TGFβ receptor in mesenchymal cells at sites of epithelial-mesenchymal interactions suggests that type-II TGFβ receptor plays a major role in mediating the establishment of embryonic organ systems. The highly restricted expression of type-II TGFβ receptor in the developing CNS suggests an important role for a serine/threonine kinase in patterning of the nervous system. © 1995.

Authors
Wang, Y-Q; Sizeland, A; Wang, X-F; Sassoon, D
MLA Citation
Wang, Y-Q, Sizeland, A, Wang, X-F, and Sassoon, D. "Restricted expression of type-II TGFβ receptor in murine embryonic development suggests a central role in tissue modeling and CNS patterning." Mechanisms of Development 52.2-3 (1995): 275-289.
PMID
8541216
Source
scival
Published In
Mechanisms of Development
Volume
52
Issue
2-3
Publish Date
1995
Start Page
275
End Page
289

Demonstration that mutation of the type II transforming growth factor β receptor inactivates its tumor suppressor activity in replication error-positive colon carcinoma cells

Escape from negative growth regulation by transforming growth factor β (TGF-β) as a result of the loss of TGF-β type II receptor (RII) expression has been found to be associated with the replication error (RER) colorectal cancer genotype, which is characteristic of hereditary nonpolyposis colorectal cancers. The RER-positive HCT 116 colon carcinoma cell line was examined for RII mutations. A 1-base deletion was found within a sequence of 10 repeating adenines (nucleotides 709-718), which resulted in a frameshift mutation. Although it is reasonable to predict that the loss of RII function would be an important determinant of malignancy, the large number of potential mutations in cells of this phenotype raises the possibility that an RII mutation may not be a key event in the tumorigenic phenotype of these cells. One way to test directly the importance of RII mutations in determining the malignant phenotype would be to restore its expression. If restoration of expression leads to diminished tumorigenicity, it would indicate that RII mutation is an important determinant of malignancy in the RER phenotype. To determine whether restoration of RII would lead to reversal of malignancy in RER colon cancers, an RII expression vector was transfected into the HCT 116 cell line. RII stable clones showed mRNA and protein expression of transfected RII. The fibronectin mRNA level was increased by exogenous TGF-β1 treatment in a dose-dependent manner in RII-positive clones, whereas the control cells remained insensitive. The RII transfectants showed reduced clonogenicity in both monolayer culture and soft agarose. They were growth arrested at a lower saturation density than control cells. TGF-β1-neutralizing antibody stimulated the proliferation of RII-transfected but not control cells, indicating that the alterations in the growth parameters of the transfected cells were due to the acquisition of autocrine-negative activity. Tumorigenicity in athymic mice was reduced and delayed in RII transfectants. These results indicate that reconstitution of TGF-β autocrine activity by reexpression of RII can reverse malignancy in RER colon cancers, thus verifying that the malignancy of hereditary nonpolyposis colorectal cancer can be directly associated with the loss of RII expression.

Authors
Wang, J; Sun, L; Myeroff, L; Wang, X; Gentry, LE; Yang, J; Liang, J; Zborowska, E; Markowitz, S; Willson, JKV; Brattain, MG
MLA Citation
Wang, J, Sun, L, Myeroff, L, Wang, X, Gentry, LE, Yang, J, Liang, J, Zborowska, E, Markowitz, S, Willson, JKV, and Brattain, MG. "Demonstration that mutation of the type II transforming growth factor β receptor inactivates its tumor suppressor activity in replication error-positive colon carcinoma cells." Journal of Biological Chemistry 270.37 (1995): 22044-22049.
PMID
7665626
Source
scival
Published In
Journal of Biological Chemistry
Volume
270
Issue
37
Publish Date
1995
Start Page
22044
End Page
22049

Signaling by the transforming growth factor-β receptor

Authors
Yingling, JM; Wang, X-F; Bassing, CH
MLA Citation
Yingling, JM, Wang, X-F, and Bassing, CH. "Signaling by the transforming growth factor-β receptor." BBA - Reviews on Cancer 1242.2 (1995): 115-136.
PMID
7492567
Source
scival
Published In
BBA - Reviews on Cancer
Volume
1242
Issue
2
Publish Date
1995
Start Page
115
End Page
136

A transforming growth factor beta type I receptor that signals to activate gene expression.

Transforming growth factor beta (TGF-beta) is a multifunctional factor that regulates many aspects of cellular functions. TGF-beta signals through a heteromeric complex of the type I and type II TGF-beta receptors. However, the molecular mechanism of signal transduction by this receptor complex remains unresolved. The type II receptor belongs to a transmembrane receptor serine-threonine kinase family. A new member of this receptor family (R4) was identified and shown to be a functional TGF-beta type I receptor on the basis of its ability to restore a TGF-beta-induced gene response in mutant cell lines lacking endogenous type I receptor. Both ligand binding and signaling of the R4 protein were dependent on the presence of a functional type II receptor. The type I receptor has an intrinsic serine-threonine kinase activity, which was essential for signal transduction.

Authors
Bassing, CH; Yingling, JM; Howe, DJ; Wang, T; He, WW; Gustafson, ML; Shah, P; Donahoe, PK; Wang, XF
MLA Citation
Bassing, CH, Yingling, JM, Howe, DJ, Wang, T, He, WW, Gustafson, ML, Shah, P, Donahoe, PK, and Wang, XF. "A transforming growth factor beta type I receptor that signals to activate gene expression." Science 263.5143 (January 7, 1994): 87-89.
PMID
8272871
Source
pubmed
Published In
Science
Volume
263
Issue
5143
Publish Date
1994
Start Page
87
End Page
89

TGF-β activates gene expression

Authors
Wang, XF
MLA Citation
Wang, XF. "TGF-β activates gene expression." Biomedicine and Pharmacotherapy 48.8-9 (1994): 410--.
Source
scival
Published In
Biomedicine & Pharmacotherapy
Volume
48
Issue
8-9
Publish Date
1994
Start Page
410-

Receptors for the TGF-beta ligand family.

Authors
Bassing, CH; Yingling, JM; Wang, XF
MLA Citation
Bassing, CH, Yingling, JM, and Wang, XF. "Receptors for the TGF-beta ligand family." Vitamins and Hormones 48 (1994): 111-156.
PMID
7941425
Source
scival
Published In
Vitamins and Hormones
Volume
48
Publish Date
1994
Start Page
111
End Page
156

A single heteromeric receptor complex is sufficient to mediate biological effects of transforming growth factor-β ligands

Transforming growth factor β (TGF-β), a multifunctional cytokine that regulates a variety of biological functions, signals through a heteromeric receptor complex of the type I and type II TGF-β receptors. The type II receptor, a transmembrane serine-threonine kinase, was cloned based on its ability to directly bind TGF-β. Recently, a number of candidate type I TGF- β receptors have been isolated. Although only one of these transmembrane kinases (R4) has been shown to mediate TGF-β-dependent gene activation, others bind TGF-β when overexpressed in COS cells. Consequently, it has been postulated that the diversity of TGF-β responses is generated through the association of distinct type I receptors with the type II TGF-β receptor, thus creating receptor complexes of differential signaling capacities. In contrast to this model, we demonstrate that stable expression of only the R4 type I TGF-β receptor in a mutant cell line lacking endogenous type I TGF- β receptor was able to complex with the endogenous type II TGF-β receptor and restore the effects of TGF-β on inhibition of cell proliferation and activation of specific genes, regardless of which of the three mammalian isoforms of TGF-β was used as the ligand. Therefore, R4 acts as a fully functional type I TGF-β receptor, and the differential effects of TGF-β are likely mediated by a single receptor complex consisting of R4 and the type II receptor.

Authors
Bassing, CH; Howe, DJ; Segarini, PR; Donahoe, PK; Wang, X-F
MLA Citation
Bassing, CH, Howe, DJ, Segarini, PR, Donahoe, PK, and Wang, X-F. "A single heteromeric receptor complex is sufficient to mediate biological effects of transforming growth factor-β ligands." Journal of Biological Chemistry 269.21 (1994): 14861-14864.
PMID
8195115
Source
scival
Published In
Journal of Biological Chemistry
Volume
269
Issue
21
Publish Date
1994
Start Page
14861
End Page
14864

Cloning and developmental expression of the chick type II and type III TGFβ receptors

To address the role of peptide growth factors in chick organogenesis, we have focused on TGFβ2 and have cloned the chick Type II and Type III TGFβ receptors. The chick Type II receptor is a serine/threonine kinase with a ligand binding profile identical to the human receptor and a divergent N- terminus when compared to the mammalian receptors. The chick Type III receptor is a betaglycan that demonstrates a binding profile identical to the rat receptor and contains a single transmembrane spanning domain and short cytoplasmic tail that are highly conserved when compared to the mammalian receptors. Both the Type II and Type III TGFβ receptors are coexpressed during chick embryogenesis in the developing heart, lung, and eye, and are developmentally upregulated in parallel in the heart and lung. Levels of both receptor proteins and mRNAs also increase in cardiocytes cultured from different developmental stages, in agreement with the increase in Type II and Type III receptor mRNA levels observed in the developing heart. Although exhibiting different temporal or spatial profiles from the receptors, TGFβ2 is also expressed in the developing heart, lung, and eye. These findings are consistent with recent data indicating that coexpression of both the Type II and Type III TGFβ receptors is required for high affinity binding of TGFβ2 by the Type II receptor and suggest that TGFβ2 and the Type II and Type III TGFβ receptors participate in heart, lung, and eye development.

Authors
Barnett, JV; Moustakas, A; Lin, W; Wang, X-F; Lin, HY; Galper, JB; Maas, RL
MLA Citation
Barnett, JV, Moustakas, A, Lin, W, Wang, X-F, Lin, HY, Galper, JB, and Maas, RL. "Cloning and developmental expression of the chick type II and type III TGFβ receptors." Developmental Dynamics 199.1 (1994): 12-27.
PMID
8167376
Source
scival
Published In
Developmental Dynamics
Volume
199
Issue
1
Publish Date
1994
Start Page
12
End Page
27

Expression of transforming growth factor β type II receptor leads to reduced malignancy in human breast cancer MCF-7 cells

The role of transforming growth factor (TGF) β type II receptor in reversing the malignant phenotype of human breast cancer MCF-7 cells was examined. MCF-7 cells were insensitive to TGFβ1 and expressed undetectable levels of cell surface TGFβ type I receptor (RI) and type II receptor (RII) by cross-linking with 125I-TGFβ1. Stable transfection of a RII expression vector yielded 3 transfectants with varying levels of exogenous RII mRNA and protein levels. Expression of RII also increased TGFβ1 binding to RI in all 3 clones. Proliferation of RII-positive clones was inhibited by exogenous TGFβ1 in a dose-dependent manner, whereas the control clones remained TGFβ-insensitive. The RII transfectants were growth arrested in monolayer culture at saturation densities which were 41-66% of that of the Neo controls. They also showed reduced clonogenicity in soft-agarose. Tumorigenicity in ovariectomized, estrogen-supplemented nude mice was delayed in transfectants with low RII levels. Transfectants expressing high levels of RII showed a large reduction in tumorigenicity as well as a longer delay in tumor formation. Tumor growth was associated with loss of exogenous RII expression in transfectants. The results indicate that when systems for TGFβ signal transduction are intact, reconstitution of the TGFβ receptor system can lead to reversion of malignancy in cells lacking RII.

Authors
Sun, L; Wu, G; Willson, JKV; Zborowska, E; Yang, J; Rajkarunanayake, I; Wang, J; Gentry, LE; Wang, X-F; Brattain, MG
MLA Citation
Sun, L, Wu, G, Willson, JKV, Zborowska, E, Yang, J, Rajkarunanayake, I, Wang, J, Gentry, LE, Wang, X-F, and Brattain, MG. "Expression of transforming growth factor β type II receptor leads to reduced malignancy in human breast cancer MCF-7 cells." Journal of Biological Chemistry 269.42 (1994): 26449-26455.
PMID
7929366
Source
scival
Published In
The Journal of biological chemistry
Volume
269
Issue
42
Publish Date
1994
Start Page
26449
End Page
26455

Expression cloning of TGF-β receptors

Using a powerful expression cloning method in COS cells, we have cloned the TGF-β types II and III receptors. The type III TGF-β receptor is a membrane-bound proteoglycan with a core protein of about 110 kDa. Stable expression of the type III receptor in L6 myoblasts leads to an apparent increase in the ability of the type II receptor to bind iodinated TGF-β1. The cloned type II receptor has a predicted protein core of about 60 kDa with a cysteine-rich extracellular domain, a single transmembrane domain, and a functional serine/threonine kinase domain that is homologous to the activin receptor and to the C. elegans protein daf-1. These results implicate serine/threonine phosphorylation as an important mechanism of TGF-β action.

Authors
Lin, HY; Wang, X-F
MLA Citation
Lin, HY, and Wang, X-F. "Expression cloning of TGF-β receptors." Molecular Reproduction and Development 32.2 (1992): 105-110.
PMID
1322147
Source
scival
Published In
Molecular Reproduction & Development
Volume
32
Issue
2
Publish Date
1992
Start Page
105
End Page
110
DOI
10.1002/mrd.1080320205

TGFβ signals through a heteromeric protein kinase receptor complex

Transforming growth factor β (TGFβ) binds with high affinity to the type II receptor, a transmembrane protein with a cytoplasmic serine/threonine kinase domain. We show that the type II receptor requires both its kinase activity and association with another TGFβ-binding protein, the type I receptor, to signal growth inhibition and early gene responses. Receptors I and II associate as interdependent components of a heteromeric complex: receptor I requires receptor II to bind TGFβ, and receptor II requires receptor I to signal. This mode of operation points to fundamental differences between this receptor and the protein-tyrosine kinase cytokine receptors.

Authors
Wrana, JL; Attisano, L; Carcamo, J; Zentella, A; Doody, J; Laiho, M; Wang-, XF; Massague, J
MLA Citation
Wrana, JL, Attisano, L, Carcamo, J, Zentella, A, Doody, J, Laiho, M, Wang-, XF, and Massague, J. "TGFβ signals through a heteromeric protein kinase receptor complex." Cell 71.6 (1992): 1003-1014.
PMID
1333888
Source
scival
Published In
Cell
Volume
71
Issue
6
Publish Date
1992
Start Page
1003
End Page
1014
DOI
10.1016/0092-8674(92)90395-S

Expression cloning of the TGF-β type II receptor, a functional transmembrane serine/threonine kinase

A cDNA encoding the TGF-β type II receptor protein has been isolated by an expression cloning strategy. The cloned cDNA, when transfected into COS cells, leads to overexpression of an ∼80 kd protein that specifically binds radioiodinated TGF-β1. Excess TGF-β1 competes for binding of radioiodinated TGF-β1 in a dose-dependent manner and is more effective than TGF-β2. The predicted receptor structure includes a cysteine-rich extracellular domain, a single hydrophobic transmembrane domain, and a predicted cytoplasmic serine/threonine kinase domain. A chimeric protein containing the intracellular domain of the type II receptor and expressed in E. coli can phosphorylate itself on serine and threonine residues in vitro, indicating that the cytoplasmic domain of the type II receptor is a functional kinase. This result implicates serine/ threonine phosphorylation as an important mechanism of TGF-β receptor-mediated signaling.

Authors
Lin, HY; Wang, X-F; Ng-Eaton, E; Weinberg, RA; Lodish, HF
MLA Citation
Lin, HY, Wang, X-F, Ng-Eaton, E, Weinberg, RA, and Lodish, HF. "Expression cloning of the TGF-β type II receptor, a functional transmembrane serine/threonine kinase." Cell 68.4 (1992): 775-785.
PMID
1310899
Source
scival
Published In
Cell
Volume
68
Issue
4
Publish Date
1992
Start Page
775
End Page
785

Expression cloning and characterization of the TGF-β type III receptor

The rat TGF-β type III receptor cDNA has been cloned by overexpression in COS cells. The encoded receptor is an 853 amino acid protein with a large N-terminal extracellular domain containing at least one site for glycosaminoglycan addition, a single hydrophobic transmembrane domain, and a 41 amino acid cytoplasmic tail with no obvious signaling motif. Introduction of the cDNA into COS cells and L6 myoblasts induces expression of a heterogenously glycosylated 280-330 kd protein characteristic of the type III receptor that binds TGF-β1 specifically. In L6 myoblasts lacking the endogenous type III receptor, expression of the recombinant receptor leads to an increase in the amount of ligand bound and cross-linked to surface type II TGF-β receptors. This indicates that the type III receptor may regulate the ligand-binding ability or surface expression of the type II receptor.

Authors
Wang, X-F; Lin, HY; Ng-Eaton, E; Downward, J; Lodish, HF; Weinberg, RA
MLA Citation
Wang, X-F, Lin, HY, Ng-Eaton, E, Downward, J, Lodish, HF, and Weinberg, RA. "Expression cloning and characterization of the TGF-β type III receptor." Cell 67.4 (1991): 797-805.
PMID
1657407
Source
scival
Published In
Cell
Volume
67
Issue
4
Publish Date
1991
Start Page
797
End Page
805

Absence of TGF-beta receptors and growth inhibitory responses in retinoblastoma cells.

The responses of retinoblastoma tumor cells and normal retinal cells to various growth inhibitory factors were examined. Whereas fetal retinal cells were highly sensitive to the antimitogenic effects of transforming growth factor beta 1 (TGF-beta 1), retinoblastoma tumor cell lines were all resistant to this factor. Binding assays and affinity labeling of these cells with radioiodinated TGF-beta 1 revealed that the cells did not have TGF-beta receptors. The retinoblastoma cells lacked the three affinity-labeled proteins of 65, 95, and 300 kilodaltons typically seen in human cell lines and thus differed from normal retinal cells and from other types of neuroectodermal tumors that display the normal pattern of receptors. Loss of TGF-beta receptors, which is a rare event among tumor cells, may represent one mechanism through which these cells escape from negative control and form retinoblastomas.

Authors
Kimchi, A; Wang, XF; Weinberg, RA; Cheifetz, S; Massagué, J
MLA Citation
Kimchi, A, Wang, XF, Weinberg, RA, Cheifetz, S, and Massagué, J. "Absence of TGF-beta receptors and growth inhibitory responses in retinoblastoma cells." Science (New York, N.Y.) 240.4849 (April 1988): 196-199.
PMID
2895499
Source
epmc
Published In
Science
Volume
240
Issue
4849
Publish Date
1988
Start Page
196
End Page
199
DOI
10.1126/science.2895499

In vivo functional analysis of in vitro protein binding sites in the immunoglobulin heavy chain enhancer

We have systematically investigated the functional role of protein binding sites within the mouse immunoglobulin heavy chain enhancer which we previously identified by in vitro binding studies (1,2). Each binding site was deleted, mutant enhancers were cloned 3′ of the chloramphenicol acetyl transferase gene in the vector pA10CAT2 and transfected into plasmacytoma cells. We demonstrate that the newly identified site E, located at 324-338 bp, is important for enhancer function; previously identified sites B(uE1), C1(uE2), C2(uE3) and C3 were also shown to be important for enhancer activity. Sites A and D are not required for IgH enhancer function, as assayed by our methods. Thus, including the octamer site, six protein binding sites which bind at least six different proteins are important for enhancer function in vivo. © 1988 IRL Press Limited.

Authors
Tsao, BP; Wang, X-F; Peterson, CL; Calame, K
MLA Citation
Tsao, BP, Wang, X-F, Peterson, CL, and Calame, K. "In vivo functional analysis of in vitro protein binding sites in the immunoglobulin heavy chain enhancer." Nucleic Acids Research 16.8 (1988): 3239-3253.
PMID
3131736
Source
scival
Published In
Nucleic Acids Research
Volume
16
Issue
8
Publish Date
1988
Start Page
3239
End Page
3253
DOI
10.1093/nar/16.8.3239

Erratum: Deletions of a DNA sequence in retinoblastomas and mesenchymal tumors: Organization of the sequence and its encoded protein (Proc., Natl. Acad. Sci. USA, No. 24, Dec. 1987 (84, 9059-9063))

Authors
Friend, SH; Horowitz, JM; Gerber, MR; Wang, X-F; Bogenmann, E; Li, FP; Weinberg, RA
MLA Citation
Friend, SH, Horowitz, JM, Gerber, MR, Wang, X-F, Bogenmann, E, Li, FP, and Weinberg, RA. "Erratum: Deletions of a DNA sequence in retinoblastomas and mesenchymal tumors: Organization of the sequence and its encoded protein (Proc., Natl. Acad. Sci. USA, No. 24, Dec. 1987 (84, 9059-9063))." Proceedings of the National Academy of Sciences of the United States of America 85.7 (1988): 2234--.
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
85
Issue
7
Publish Date
1988
Start Page
2234-
DOI
10.1073/pnas.85.7.2234

Absence of TGF-β receptors and growth inhibitory responses in retinoblastoma cells

The responses of retinoblastoma tumor cells and normal retinal cells to various growth inhibitory factors were examined. Whereas fetal retinal cells were highly sensitive to the antimitogenic effects of transforming growth factor β1 (TGF-β1), retinoblastoma tumor cell lines were all resistant to this factor. Binding assays and affinity labeling of these cells with radioiodinated TGF-β1 revealed that the cells did not have TGF-β receptors. The retinoblastoma cells lacked the three affinity-labeled proteins of 65, 95, and 300 kilodaltons typically seen in human cell lines and thus differed from normal retinal cells and from other types of neuroectodermal tumors that display the normal pattern of receptors. Loss of TGF-β receptors, which is a rare event among tumor cells, may represent one mechanism through which these cells escape from negative control and form retinoblastomas.

Authors
Kimchi, A; Wang, X-F; Weinberg, RA; Cheifetz, S; Massague, J
MLA Citation
Kimchi, A, Wang, X-F, Weinberg, RA, Cheifetz, S, and Massague, J. "Absence of TGF-β receptors and growth inhibitory responses in retinoblastoma cells." Science 239.4849 (1988): 196-199.
Source
scival
Published In
Science
Volume
239
Issue
4849
Publish Date
1988
Start Page
196
End Page
199

Deletions of a DNA sequence in retinoblastomas and mesenchymal tumors: organization of the sequence and its encoded protein.

Retinoblastoma is a childhood tumor that can arise because of mutant alleles acquired as somatic or germinal mutations. The mutant allele can be carried in the germ line. The mutations creating these alleles act by inactivating copies of a recessive oncogene located within band q14 of chromosome 13 and termed the RB1 locus. We have reported isolation of a cDNA fragment that recognizes chromosomal sequences possessing many of the attributes of the retinoblastoma gene associated with the RB1 locus. We now report that this segment is additionally the target of somatic mutations in mesenchymal tumors among patients having no apparent predisposition to retinoblastoma and no previous evidence of retinoblastoma. These tumors provide additional evidence that the cloned sequences are representative of a gene that is a frequent target of inactivation during tumorigenesis. Sequence analysis of this cDNA provides little insight into its normal functional role.

Authors
Friend, SH; Horowitz, JM; Gerber, MR; Wang, XF; Bogenmann, E; Li, FP; Weinberg, RA
MLA Citation
Friend, SH, Horowitz, JM, Gerber, MR, Wang, XF, Bogenmann, E, Li, FP, and Weinberg, RA. "Deletions of a DNA sequence in retinoblastomas and mesenchymal tumors: organization of the sequence and its encoded protein." Proceedings of the National Academy of Sciences of the United States of America 84.24 (1987): 9059-9063.
PMID
3480530
Source
scival
Published In
Proceedings of the National Academy of Sciences of the United States of America
Volume
84
Issue
24
Publish Date
1987
Start Page
9059
End Page
9063

SV40 enhancer-binding factors are required at the establishment but not the maintenance step of enhancer-dependent transcriptional activation.

We have used temperature-sensitive COS cells to design delayed competition experiments in which competition for simian virus 40 (SV40) enhancer factors occurs after enhancer-dependent transcription has been established. The results demonstrate that competition for SV40 enhancer-binding factors has no effect on enhancer-dependent transcription after transcription has been established at the SV40 early promoter. These data show that the enhancer and factors that bind to it are involved in the establishment of stable transcription complexes, although they do not show whether enhancer factors are an integral part of the transcription complexes. Furthermore, the results of delayed competition experiments with a replicating test plasmid are consistent with the possibility that enhancer-dependent stable transcription complexes could be maintained after DNA replication.

Authors
Wang, XF; Calame, K
MLA Citation
Wang, XF, and Calame, K. "SV40 enhancer-binding factors are required at the establishment but not the maintenance step of enhancer-dependent transcriptional activation." Cell 47.2 (October 1986): 241-247.
PMID
3021335
Source
epmc
Published In
Cell
Volume
47
Issue
2
Publish Date
1986
Start Page
241
End Page
247
DOI
10.1016/0092-8674(86)90446-0

The endogenous immunoglobulin heavy chain enhancer can activate tandem VH promoters separated by a large distance

The availability of a clone containing two linked immunoglobulin heavy chain variable region genes located 15.8 kb apart has allowed us to study the functional capabilities of the immunoglobulin heavy chain transcriptional enhancer element in its normal chromosomal context. In plasmacytoma J606 the 3′ VH gene is joined to D and J gene segments, located within 1.7 kb of the heavy chain enhancer, and expressed; the 5′ VH gene is 17.5 kb from the enhancer in J606 DNA. Run-on transcription in isolated nuclei demonstrated specific transcription of the 5′ VH gene in J606 that was 60% that of the expressed 3′ VH gene. No other enhancer elements are detectable closer to the 5′ VH gene than the known heavy chain enhancer. Thus, the heavy chain enhancer appears to be capable of activating transcription of a VH promoter located 17.5 kb away and of activating two tandem VH promoters. © 1985.

Authors
Wang, X-F; Calame, K
MLA Citation
Wang, X-F, and Calame, K. "The endogenous immunoglobulin heavy chain enhancer can activate tandem VH promoters separated by a large distance." Cell 43.3 PART 2 (1985): 659-665.
PMID
2866846
Source
scival
Published In
Cell
Volume
43
Issue
3 PART 2
Publish Date
1985
Start Page
659
End Page
665

Transcriptional enhancer elements in the mouse immunoglobulin heavy chain locus

Two regions in the immunoglobulin heavy chain locus were tested for their ability to enhance transcription of the SV40 early promoter. A portion of the intervening sequence between the heavy chain joining region (J(h)) and the constant region of the μ chain (Cμ) can enhance transcription when it is cloned either 5' or 3' to the SV40 early promoter. The region between Cα and the alpha switch site, which occurs 5' to the translocated c-myc oncogene in many murine plasmacytomas, does not show transcriptional enhancer activity in this assay.

Authors
Mercola, M; Wang, XF; Olsen, J; Calame, K
MLA Citation
Mercola, M, Wang, XF, Olsen, J, and Calame, K. "Transcriptional enhancer elements in the mouse immunoglobulin heavy chain locus." Science 221.4611 (1983): 663-665.
PMID
6306772
Source
scival
Published In
Science
Volume
221
Issue
4611
Publish Date
1983
Start Page
663
End Page
665
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