1
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Qi M, Yi X, Yue B, Huang M, Zhou S, Xiong J. S100A6 inhibits MDM2 to suppress breast cancer growth and enhance sensitivity to chemotherapy. Breast Cancer Res 2023; 25:55. [PMID: 37217945 DOI: 10.1186/s13058-023-01657-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND S100A6 and murine double minute 2 (MDM2) are important cancer-related molecules. A previous study identified an interaction between S100A6 and MDM2 by size exclusion chromatography and surface plasmon resonance experiments. The present study investigated whether S100A6 could bind to MDM2 in vivo and further explored its functional implication. METHODS Co-immunoprecipitation, glutathione-S-transferase pull-down assay, and immunofluorescence were performed to determine the in vivo interaction between S100A6 and MDM2. Cycloheximide pulse-chase assay and ubiquitination assay were performed to clarify the mechanism by which S100A6 downregulated MDM2. In addition, clonogenic assay, WST-1 assay, and flow cytometry of apoptosis and the cell cycle were performed and a xenograft model was established to evaluate the effects of the S100A6/MDM2 interaction on growth and paclitaxel-induced chemosensitivity of breast cancer. The expressions of S100A6 and MDM2 in patients with invasive breast cancer were analyzed by immunohistochemistry. In addition, the correlation between the expression of S100A6 and the response to neoadjuvant chemotherapy was statistically analyzed. RESULTS S100A6 promoted the MDM2 translocation from nucleus to cytoplasm, in which the S100A6 bound to the binding site of the herpesvirus-associated ubiquitin-specific protease (HAUSP) in MDM2, disrupted the MDM2-HAUSP-DAXX interactions, and induced the MDM2 self-ubiquitination and degradation. Furthermore, the S100A6-mediated MDM2 degradation suppressed the growth of breast cancer and enhanced its sensitivity to paclitaxel both in vitro and in vivo. For patients with invasive breast cancer who received epirubicin and cyclophosphamide followed by docetaxel (EC-T), expressions of S100A6 and MDM2 were negatively correlated, and high expression of S100A6 suggested a higher rate of pathologic complete response (pCR). Univariate and multivariate analyses showed that the high expression of S100A6 was an independent predictor of pCR. CONCLUSION These results reveal a novel function for S100A6 in downregulating MDM2, which directly enhances sensitivity to chemotherapy.
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Affiliation(s)
- Mengxin Qi
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xianglan Yi
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Baohui Yue
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Mingxiang Huang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Sheng Zhou
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Jing Xiong
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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2
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de Oliveira Ribeiro H, Cortez AP, de Ávila RI, da Silva ACG, de Carvalho FS, Menegatti R, Lião LM, Valadares MC. Small-molecule MDM2 inhibitor LQFM030-induced apoptosis in p53-null K562 chronic myeloid leukemia cells. Fundam Clin Pharmacol 2020; 34:444-457. [PMID: 32011031 DOI: 10.1111/fcp.12540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 01/01/2023]
Abstract
Our group designed and synthesized the N-phenyl-piperazine LQFM030 [1-(4-((1-(4-chlorophenyl)-1H-pyrazol-4-yl)methyl) piperazin-1-yl) ethanone], a small molecule derived from molecular simplification of the Nutlin-1, an inhibitor of the human homologue of murine double minute 2 (MDM2) protein that is expressed in several types of cancer. To better investigate the effects of LQFM030 regarding the p53 mutation status, this study investigated the antiproliferative activity of LQFM030 against the p53-null K562 leukemia cells as well as the cell death pathways involved. In addition, the effects of LQFM030 on the levels of the p53/MDM2 complex were also carried out using 3T3 cells as a p53 wild-type model. Our data suggest that LQFM030 triggered apoptosis in K562 cells via different mechanisms including cell cycle arrest, caspase activation, reduction of mitochondrial activity, decrease in MDM2 expression, and transcriptional modulation of MDMX, p73, MYC, and NF-ĸB. Additionally, it promoted effects in p53/MDM2 binding in p53 wild-type 3T3 cells. Therefore, LQFM030 has antiproliferative effects in cancer cells by a p53 mutation status-independent manner with different signaling pathways. These findings open new perspectives to the treatment of leukemic cells considering the resistance development associated with cancer treatment with conventional cytotoxic drugs.
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Affiliation(s)
- Higor de Oliveira Ribeiro
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Alane Pereira Cortez
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Renato Ivan de Ávila
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Artur Christian Garcia da Silva
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Flávio Silva de Carvalho
- Laboratório de Química Farmacêutica Medicinal (LQFM), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Ricardo Menegatti
- Laboratório de Química Farmacêutica Medicinal (LQFM), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Luciano Morais Lião
- Laboratório de Ressonância Magnética Nuclear, Instituto de Química, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Marize Campos Valadares
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
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3
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Song H, Sun B, Liao Y, Xu D, Guo W, Wang T, Jing B, Hu M, Li K, Yao F, Deng J. GPRC5A deficiency leads to dysregulated MDM2 via activated EGFR signaling for lung tumor development. Int J Cancer 2018; 144:777-787. [PMID: 29992578 DOI: 10.1002/ijc.31726] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/09/2018] [Accepted: 06/20/2018] [Indexed: 11/07/2022]
Abstract
GPRC5A, a retinoic acid induced gene, is preferentially expressed in lung tissue. Gprc5a gene deletion leads to spontaneous lung tumor development. However, the mechanism of Gprc5a-mediated lung tumor suppression is not fully understood. Here we showed that MDM2, a p53-negative regulator, was dysregulated in Gprc5a-knockout (ko) mouse tracheal epithelial cells (KO-MTEC) compared to wild type ones. Targeting MDM2 in 1601-a Gprc5a-ko mouse derived lung tumor cell line-and A549-human lung cancer cells, by MDM2 inhibitor Nutlin-3a or small hairpin RNA (sh-RNA)-restored p53 signaling pathway, reduced cancer stem cell markers, and inhibited tumorigenicity. This suggests that dysregulated MDM2 pathway is essential for the oncogenic activities of these cells. MDM2 was found to be stabilized mainly by activated EGFR signaling as targeting EGFR by Erlotinib or sh-RNA repressed MDM2 in a transcription-independent manner. Importantly, overexpression of MDM2 and reduced GPRC5A expression at both protein and mRNA levels were frequently found in clinical human lung cancer tissues. Taken together, GPRC5A deficiency contributes to dysregulated MDM2 via activated EGFR signaling, which promotes lung tumor development.
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Affiliation(s)
- Hongyong Song
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Beibei Sun
- Translation Medicine Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yueling Liao
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dongliang Xu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenzheng Guo
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tong Wang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bo Jing
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Min Hu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Kaimi Li
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Feng Yao
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jiong Deng
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Minister of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Translation Medicine Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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Nör F, Warner KA, Zhang Z, Acasigua GA, Pearson AT, Kerk SA, Helman JI, Sant'Ana Filho M, Wang S, Nör JE. Therapeutic Inhibition of the MDM2-p53 Interaction Prevents Recurrence of Adenoid Cystic Carcinomas. Clin Cancer Res 2016; 23:1036-1048. [PMID: 27550999 DOI: 10.1158/1078-0432.ccr-16-1235] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/13/2016] [Accepted: 08/15/2016] [Indexed: 01/10/2023]
Abstract
Purpose: Conventional chemotherapy has modest efficacy in advanced adenoid cystic carcinomas (ACC). Tumor recurrence is a major challenge in the management of ACC patients. Here, we evaluated the antitumor effect of a novel small-molecule inhibitor of the MDM2-p53 interaction (MI-773) combined with cisplatin in patient-derived xenograft (PDX) ACC tumors.Experimental Design: Therapeutic strategies with MI-773 and/or cisplatin were evaluated in SCID mice harboring PDX ACC tumors (UM-PDX-HACC-5) and in low passage primary human ACC cells (UM-HACC-2A, -2B, -5, -6) in vitro The effect of therapy on the fraction of cancer stem cells (CSC) was determined by flow cytometry for ALDH activity and CD44 expression.Results: Combined therapy with MI-773 with cisplatin caused p53 activation, induction of apoptosis, and regression of ACC PDX tumors. Western blots revealed induction of MDM2, p53 and downstream p21 expression, and regulation of apoptosis-related proteins PUMA, BAX, Bcl-2, Bcl-xL, and active caspase-9 upon MI-773 treatment. Both single-agent MI-773 and MI-773 combined with cisplatin decreased the fraction of CSCs in PDX ACC tumors. Notably, neoadjuvant MI-773 and surgery eliminated tumor recurrences during a postsurgical follow-up of more than 300 days. In contrast, 62.5% of mice that received vehicle control presented with palpable tumor recurrences within this time period (P = 0.0097).Conclusions: Collectively, these data demonstrate that therapeutic inhibition of MDM2-p53 interaction by MI-773 decreased the CSC fraction, sensitized ACC xenograft tumors to cisplatin, and eliminated tumor recurrence. These results suggest that patients with ACC might benefit from the therapeutic inhibition of the MDM2-p53 interaction. Clin Cancer Res; 23(4); 1036-48. ©2016 AACR.
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Affiliation(s)
- Felipe Nör
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan.,Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Kristy A Warner
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Zhaocheng Zhang
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Gerson A Acasigua
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan.,Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Alexander T Pearson
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan.,Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Samuel A Kerk
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Joseph I Helman
- Department of Oral and Maxillofacial Surgery, University of Michigan School of Dentistry, Ann Arbor, Michigan.,University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan, USA
| | - Manoel Sant'Ana Filho
- Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Shaomeng Wang
- Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan.,University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan, USA.,Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan.,Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Ann Arbor, Michigan
| | - Jacques E Nör
- Department of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan. .,University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan, USA.,Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, Michigan.,Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, Michigan
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5
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Warner KA, Nör F, Acasigua GA, Martins MD, Zhang Z, McLean SA, Spector ME, Chepeha DB, Helman J, Wick MJ, Moskaluk CA, Castilho RM, Pearson AT, Wang S, Nör JE. Targeting MDM2 for Treatment of Adenoid Cystic Carcinoma. Clin Cancer Res 2016; 22:3550-9. [PMID: 26936915 DOI: 10.1158/1078-0432.ccr-15-1698] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 02/08/2016] [Indexed: 02/05/2023]
Abstract
PURPOSE There are no effective treatment options for patients with advanced adenoid cystic carcinoma (ACC). Here, we evaluated the effect of a new small molecule inhibitor of the MDM2-p53 interaction (MI-773) in preclinical models of ACC. EXPERIMENTAL DESIGN To evaluate the anti-tumor effect of MI-773, we administered it to mice harboring three different patient-derived xenograft (PDX) models of ACC expressing functional p53. The effect of MI-773 on MDM2, p53, phospho-p53, and p21 was examined by Western blots in 5 low passage primary human ACC cell lines and in MI-773-treated PDX tumors. RESULTS Single-agent MI-773 caused tumor regression in the 3 PDX models of ACC studied here. For example, we observed a tumor growth inhibition index of 127% in UM-PDX-HACC-5 tumors that was associated with an increase in the fraction of apoptotic cells (P = 0.015). The number of p53-positive cells was increased in MI-773-treated PDX tumors (P < 0.001), with a correspondent shift in p53 localization from the nucleus to the cytoplasm. Western blots demonstrated that MI-773 potently induced expression of p53 and its downstream targets p21, MDM2, and induced phosphorylation of p53 (serine 392) in low passage primary human ACC cells. Notably, MI-773 induced a dose-dependent increase in the fraction of apoptotic ACC cells and in the fraction of cells in the G1 phase of cell cycle (P < 0.05). CONCLUSIONS Collectively, these data demonstrate that therapeutic inhibition of the MDM2-p53 interaction with MI-773 activates downstream effectors of apoptosis and causes robust tumor regression in preclinical models of ACC. Clin Cancer Res; 22(14); 3550-9. ©2016 AACR.
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Affiliation(s)
- Kristy A Warner
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Felipe Nör
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan. Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gerson A Acasigua
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan. Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Manoela D Martins
- Department of Oral Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Zhaocheng Zhang
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Scott A McLean
- Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, Michigan. University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan
| | - Matthew E Spector
- Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, Michigan. University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan
| | - Douglas B Chepeha
- Department of Otolaryngology, University of Toronto, Ontario, Canada
| | - Joseph Helman
- University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan. Department of Oral and Maxillofacial Surgery, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Michael J Wick
- South Texas Accelerated Research Therapeutics, San Antonio, Texas
| | | | - Rogerio M Castilho
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Alexander T Pearson
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan. University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan. Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Shaomeng Wang
- University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan. Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan. Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan. Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Ann Arbor, Michigan
| | - Jacques E Nör
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan. Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, Michigan. University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan. Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, Michigan.
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6
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Macher-Goeppinger S, Keith M, Tagscherer KE, Singer S, Winkler J, Hofmann TG, Pahernik S, Duensing S, Hohenfellner M, Kopitz J, Schirmacher P, Roth W. PBRM1 (BAF180) protein is functionally regulated by p53-induced protein degradation in renal cell carcinomas. J Pathol 2015; 237:460-71. [PMID: 26178300 DOI: 10.1002/path.4592] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 06/23/2015] [Accepted: 07/13/2015] [Indexed: 01/28/2023]
Abstract
About 40% of clear-cell renal cell carcinomas (ccRCC) harbour mutations in Polybromo-1 (PBRM1), encoding the BAF180 subunit of a SWI/SNF chromatin remodelling complex. This qualifies PBRM1 as a major cancer gene in ccRCC. The PBRM1 protein alters chromatin structure and its known functions include transcriptional regulation by controlling the accessibility of DNA and influencing p53 transcriptional activity. Since little is known about the regulation of PBRM1, we studied possible mechanisms and interaction partners involved in the regulation of PBRM1 expression. Activation of p53 in RCC cells resulted in a marked decrease of PBRM1 protein levels. This effect was abolished by siRNA-mediated down-regulation of p53, and transcriptional activity was not crucial for p53-dependent PBRM1 regulation. Pulse-chase experiments determined post-translational protein degradation to be the underlying mechanism for p53-dependent PBRM1 regulation, which was accordingly inhibited by proteasome inhibitors. The effects of p53 activation on PBRM1 expression were confirmed in RCC tissue ex vivo. Our results demonstrate that PBRM1 is a target of p53-induced proteasomal protein degradation and provide further evidence for the influence of PBRM1 on p53 function in RCC tumour cells. Considering the paramount role of p53 in carcinogenesis and the presumptive impact of PBRM1 in RCC development, this novel regulation mechanism might be therapeutically exploited in the future.
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Affiliation(s)
- Stephan Macher-Goeppinger
- Institute of Pathology, University Hospital Heidelberg, Germany.,Molecular Tumour Pathology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Martina Keith
- Institute of Pathology, University Hospital Heidelberg, Germany.,Molecular Tumour Pathology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Katrin E Tagscherer
- Institute of Pathology, University Hospital Heidelberg, Germany.,Molecular Tumour Pathology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Stephan Singer
- Institute of Pathology, University Hospital Heidelberg, Germany
| | - Juliane Winkler
- Institute of Pathology, University Hospital Heidelberg, Germany
| | - Thomas G Hofmann
- Cellular Senescence, German Cancer Research Centre (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Sascha Pahernik
- Department of Urology, University Hospital Heidelberg, Germany
| | - Stefan Duensing
- Molecular Uro-oncology, Department of Urology, University Hospital Heidelberg, Germany
| | | | - Juergen Kopitz
- Department of Applied Tumour Biology, Institute of Pathology, University Hospital Heidelberg, Germany
| | | | - Wilfried Roth
- Institute of Pathology, University Hospital Heidelberg, Germany.,Molecular Tumour Pathology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
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7
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Study of MDM2 and SUMO-1 expression in actinic cheilitis and lip cancer. Arch Dermatol Res 2014; 306:837-41. [DOI: 10.1007/s00403-014-1500-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 08/26/2014] [Accepted: 09/07/2014] [Indexed: 01/10/2023]
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8
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Proietti S, Cucina A, Dobrowolny G, D'Anselmi F, Dinicola S, Masiello MG, Pasqualato A, Palombo A, Morini V, Reiter RJ, Bizzarri M. Melatonin down-regulates MDM2 gene expression and enhances p53 acetylation in MCF-7 cells. J Pineal Res 2014; 57:120-9. [PMID: 24920214 DOI: 10.1111/jpi.12150] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/06/2014] [Indexed: 01/10/2023]
Abstract
Compelling evidence demonstrated that melatonin increases p53 activity in cancer cells. p53 undergoes acetylation to be stabilized and activated for driving cells destined for apoptosis/growth inhibition. Over-expression of p300 induces p53 acetylation, leading to cell growth arrest by increasing p21 expression. In turn, p53 activation is mainly regulated in the nucleus by MDM2. MDM2 also acts as E3 ubiquitin ligase, promoting the proteasome-dependent p53 degradation. MDM2 entry into the nucleus is finely tuned by two different modulations: the ribosomal protein L11, acts by sequestering MDM2 in the cytosol, whereas the PI3K-AkT-dependent MDM2 phosphorylation is mandatory for MDM2 translocation across the nuclear membrane. In addition, MDM2-dependent targeting of p53 is regulated in a nonlinear fashion by MDM2/MDMX interplay. Melatonin induces both cell growth inhibition and apoptosis in MCF7 breast cancer cells. We previously reported that this effect is associated with reduced MDM2 levels and increased p53 activity. Herein, we demonstrated that melatonin drastically down-regulates MDM2 gene expression and inhibits MDM2 shuttling into the nucleus, given that melatonin increases L11 and inhibits Akt-PI3K-dependent MDM2 phosphorylation. Melatonin induces a 3-fold increase in both MDMX and p300 levels, decreasing simultaneously Sirt1, a specific inhibitor of p300 activity. Consequently, melatonin-treated cells display significantly higher values of both p53 and acetylated p53. Thus, a 15-fold increase in p21 levels was observed in melatonin-treated cancer cells. Our results provide evidence that melatonin enhances p53 acetylation by modulating the MDM2/MDMX/p300 pathway, disclosing new insights for understanding its anticancer effect.
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Affiliation(s)
- Sara Proietti
- Department of Surgery "P. Valdoni", "Sapienza" University of Rome, Rome, Italy
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9
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Alam MJ, Devi GR, Ravins, Ishrat R, Agarwal SM, Singh RKB. Switching p53 states by calcium: dynamics and interaction of stress systems. MOLECULAR BIOSYSTEMS 2013; 9:508-21. [PMID: 23360948 DOI: 10.1039/c3mb25277a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The integration of calcium and a p53-Mdm2 oscillator model is studied using a deterministic as well as a stochastic approach, to investigate the impact of a calcium wave on single cell dynamics and on the inter-oscillator interaction. The high dose of calcium in the system activates the nitric oxide synthase, synthesizing nitric oxide which then downregulates Mdm2 and influences drastically the p53-Mdm2 network regulation, lifting the system from a normal to a stressed state. The increase in calcium level switches the system to different states, as identified by the different behaviours of the p53 temporal dynamics, i.e. oscillation death to sustain the oscillation state via a mixed state of dampened and oscillation death states. Further increase of the calcium dose in the system switches the system from sustained to oscillation death state again, while an excess of calcium shifts the cell to an apoptotic state. Another important property of the calcium ion is its ability to behave as a synchronizing agent among the interacting systems. The time evolution of the p53 dynamics of the two diffusively coupled systems at stress condition via Ca(2+) shows synchronization between the two systems. The noise contained in the system interestingly helps the system to maintain its stabilized state (normal condition). However, noise has the tendency to destruct the synchronization effect, which means that it tries to restrict the system from external signals to maintain its normal condition. However, at the stress condition, the synchronization rate is found to be faster.
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Affiliation(s)
- Md Jahoor Alam
- Center for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, 110025, India
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10
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Oliveira Alves MG, Balducci I, Rodarte Carvalho Y, Cabral LAG, Nunes FD, Almeida JD. Evaluation of the expression of p53, MDM2, and SUMO-1 in oral lichen planus. Oral Dis 2013; 19:775-80. [DOI: 10.1111/odi.12068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/24/2012] [Accepted: 12/26/2012] [Indexed: 01/10/2023]
Affiliation(s)
- MG Oliveira Alves
- Department of Biosciences and Oral Diagnosis; São José dos Campos Dental School; UNESP - Univ Estadual Paulista; São José dos Campos; São Paulo; Brazil
| | - I Balducci
- Department of Social Science and Pediatric Dentisty; São José dos Campos Dental School; UNESP - Univ Estadual Paulista; São José dos Campos; São Paulo; Brazil
| | - Y Rodarte Carvalho
- Department of Biosciences and Oral Diagnosis; São José dos Campos Dental School; UNESP - Univ Estadual Paulista; São José dos Campos; São Paulo; Brazil
| | - LAG Cabral
- Department of Biosciences and Oral Diagnosis; São José dos Campos Dental School; UNESP - Univ Estadual Paulista; São José dos Campos; São Paulo; Brazil
| | - FD Nunes
- Department of Oral Pathology; School of Dentistry; University of São Paulo; São Paulo; São Paulo; Brazil
| | - JD Almeida
- Department of Biosciences and Oral Diagnosis; São José dos Campos Dental School; UNESP - Univ Estadual Paulista; São José dos Campos; São Paulo; Brazil
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11
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Protein-protein interactions and multi-component complexes of aminoacyl-tRNA synthetases. Top Curr Chem (Cham) 2013; 344:119-44. [PMID: 24072587 DOI: 10.1007/128_2013_479] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Protein-protein interaction occurs transiently or stably when two or more proteins bind together to mediate a wide range of cellular processes such as protein modification, signal transduction, protein trafficking, and structural folding. The macromolecules involved in protein biosynthesis such as aminoacyl-tRNA synthetase (ARS) have a number of protein-protein interactions. The mammalian multi-tRNA synthetase complex (MSC) consists of eight different enzymes: EPRS, IRS, LRS, QRS, MRS, KRS, RRS, and DRS, and three auxiliary proteins: AIMP1/p43, AIMP2/p38, and AIMP/p18. The distinct ARS proteins are also connected to diverse protein networks to carry out biological functions. In this chapter we first show the protein networks of the entire MSC and explain how MSC components interact with or can regulate other proteins. Finally, it is pointed out that the understanding of protein-protein interaction mechanism will provide insight to potential therapeutic application for diseases related to the MSC network.
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12
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Zhang X, Zhang Z, Cheng J, Li M, Wang W, Xu W, Wang H, Zhang R. Transcription factor NFAT1 activates the mdm2 oncogene independent of p53. J Biol Chem 2012; 287:30468-76. [PMID: 22787160 DOI: 10.1074/jbc.m112.373738] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the MDM2-p53 interaction has been well documented, MDM2 overexpression is observed in human cancers with little or no functional p53, suggesting that mdm2 expression is regulated by mechanisms independent of p53. Dysregulation of NFAT signaling is associated with malignant transformation and cancer development and progression. In this study, we demonstrate that the human mdm2 P2 promoter contains a consensus binding site for the NFAT1 transcription factor. NFAT1 directly binds the mdm2 P2 promoter in vitro and in vivo, resulting in the up-regulation of mdm2 transcription. Enforced expression of NFAT1 results in an elevated MDM2 protein level and reduces p53 activation and function in response to DNA damage. Both NFAT1 and MDM2 are highly expressed in human hepatocellular carcinoma tissues, compared with adjacent normal liver tissues. There is a positive correlation between the NFAT1 and MDM2 levels in tumor tissues. The novel function of NFAT1 in the control of MDM2 expression provides a basis for future investigations of the role of NFAT1 in cancer development, progression, and therapy.
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Affiliation(s)
- Xu Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
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13
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Zerrouqi A, Pyrzynska B, Febbraio M, Brat DJ, Van Meir EG. P14ARF inhibits human glioblastoma-induced angiogenesis by upregulating the expression of TIMP3. J Clin Invest 2012; 122:1283-95. [PMID: 22378045 DOI: 10.1172/jci38596] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 01/11/2012] [Indexed: 11/17/2022] Open
Abstract
Malignant gliomas are the most common and the most lethal primary brain tumors in adults. Among malignant gliomas, 60%-80% show loss of P14ARF tumor suppressor activity due to somatic alterations of the INK4A/ARF genetic locus. The tumor suppressor activity of P14ARF is in part a result of its ability to prevent the degradation of P53 by binding to and sequestering HDM2. However, the subsequent finding of P14ARF loss in conjunction with TP53 gene loss in some tumors suggests the protein may have other P53-independent tumor suppressor functions. Here, we report what we believe to be a novel tumor suppressor function for P14ARF as an inhibitor of tumor-induced angiogenesis. We found that P14ARF mediates antiangiogenic effects by upregulating expression of tissue inhibitor of metalloproteinase-3 (TIMP3) in a P53-independent fashion. Mechanistically, this regulation occurred at the gene transcription level and was controlled by HDM2-SP1 interplay, where P14ARF relieved a dominant negative interaction of HDM2 with SP1. P14ARF-induced expression of TIMP3 inhibited endothelial cell migration and vessel formation in response to angiogenic stimuli produced by cancer cells. The discovery of this angiogenesis regulatory pathway may provide new insights into P53-independent P14ARF tumor-suppressive mechanisms that have implications for the development of novel therapies directed at tumors and other diseases characterized by vascular pathology.
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Affiliation(s)
- Abdessamad Zerrouqi
- Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, School of Medicine, Emory University, Atlanta, Georgia 30322, USA
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14
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Inuzuka H, Fukushima H, Shaik S, Wei W. Novel insights into the molecular mechanisms governing Mdm2 ubiquitination and destruction. Oncotarget 2011; 1:685-90. [PMID: 21317463 DOI: 10.18632/oncotarget.101011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Mdm2/p53 pathway is compromised in more than 50% of all human cancers, therefore it is an intensive area of research to understand the upstream regulatory pathways governing Mdm2/p53 activity. Mdm2 is frequently overexpressed in human cancers while the molecular mechanisms underlying the timely destruction of Mdm2 remain unclear. We recently reported that Casein Kinase I phosphorylates Mdm2 at multiple sites to trigger Mdm2 interaction with, and subsequent ubiquitination and destruction by the SCF(β-TRCP) E3 ubiquitin ligase. We also demonstrated that the E3 ligase activity-deficient Mdm2 was still unstable in the G1 phase and could be efficiently degraded by SCF(β-TRCP). Thus our finding expands the current knowledge on how Mdm2 is tightly regulated by both self- and SCF(β-TRCP)-dependent ubiquitination to control p53 activity in response to stress. It further indicates that loss of β-TRCP or Casein Kinase I function contributes to elevated Mdm2 expression that is frequently found in various types of tumors.
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Affiliation(s)
- Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
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15
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Furlan A, Stagni V, Hussain A, Richelme S, Conti F, Prodosmo A, Destro A, Roncalli M, Barilà D, Maina F. Abl interconnects oncogenic Met and p53 core pathways in cancer cells. Cell Death Differ 2011; 18:1608-16. [PMID: 21455220 DOI: 10.1038/cdd.2011.23] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The simplicity of BCR-ABL 'oncogene addiction' characterizing leukemia contrasts with the complexity of solid tumors where multiple 'core pathways', including receptor tyrosine kinases (RTKs) and p53, are often altered. This discrepancy illustrates the limited success of RTK antagonists in solid tumor treatment compared with the impact of Imatinib in BCR-ABL-dependent leukemia. Here, we identified c-Abl as a signaling node interconnecting Met-RTK and p53 core pathways, and showed that its inhibition impairs Met-dependent tumorigenesis. Met ensures cell survival through a new path in which c-Abl and p38-MAPK are employed to elicit p53 phosphorylation on Ser(392) and Mdm2 upregulation. We found a clinical correlation between activated Met, phospho-p53, and Mdm2 levels in human tumors, supporting the role of this path in tumorigenesis. Our findings introduce the concept that RTK-driven tumors may be therapeutically treated by hitting signaling nodes interconnecting core pathways. Moreover, they underline the importance of evaluating the relevance of c-Abl antagonists for combined therapies, based on the tumor signaling signature.
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Affiliation(s)
- A Furlan
- Developmental Biology Institute of Marseille-Luminy (IBDML), UMR 6216, CNRS - Inserm - Université de la Méditerranée, Campus de Luminy-Case 907, 13288 Marseille Cedex 9, France
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16
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Inuzuka H, Fukushima H, Shaik S, Wei W. Novel insights into the molecular mechanisms governing Mdm2 ubiquitination and destruction. Oncotarget 2010; 1:685-690. [PMID: 21317463 PMCID: PMC3248122 DOI: 10.18632/oncotarget.202] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 10/18/2010] [Indexed: 01/10/2023] Open
Abstract
The Mdm2/p53 pathway is compromised in more than 50% of all human cancers, therefore it is an intensive area of research to understand the upstream regulatory pathways governing Mdm2/p53 activity. Mdm2 is frequently overexpressed in human cancers while the molecular mechanisms underlying the timely destruction of Mdm2 remain unclear. We recently reported that Casein Kinase I phosphorylates Mdm2 at multiple sites to trigger Mdm2 interaction with, and subsequent ubiquitination and destruction by the SCF(β-TRCP) E3 ubiquitin ligase. We also demonstrated that the E3 ligase activity-deficient Mdm2 was still unstable in the G1 phase and could be efficiently degraded by SCF(β-TRCP). Thus our finding expands the current knowledge on how Mdm2 is tightly regulated by both self- and SCF(β-TRCP)-dependent ubiquitination to control p53 activity in response to stress. It further indicates that loss of β-TRCP or Casein Kinase I function contributes to elevated Mdm2 expression that is frequently found in various types of tumors.
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17
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Inuzuka H, Tseng A, Gao D, Zhai B, Zhang Q, Shaik S, Wan L, Ang XL, Mock C, Yin H, Stommel JM, Gygi S, Lahav G, Asara J, Jim Xiao ZX, Kaelin WG, Harper JW, Wei W. Phosphorylation by casein kinase I promotes the turnover of the Mdm2 oncoprotein via the SCF(beta-TRCP) ubiquitin ligase. Cancer Cell 2010; 18:147-59. [PMID: 20708156 PMCID: PMC2923652 DOI: 10.1016/j.ccr.2010.06.015] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 01/20/2010] [Accepted: 06/28/2010] [Indexed: 01/10/2023]
Abstract
Mdm2 is the major negative regulator of the p53 pathway. Here, we report that Mdm2 is rapidly degraded after DNA damage and that phosphorylation of Mdm2 by casein kinase I (CKI) at multiple sites triggers its interaction with, and subsequent ubiquitination and destruction, by SCF(beta-TRCP). Inactivation of either beta-TRCP or CKI results in accumulation of Mdm2 and decreased p53 activity, and resistance to apoptosis induced by DNA damaging agents. Moreover, SCF(beta-TRCP)-dependent Mdm2 turnover also contributes to the control of repeated p53 pulses in response to persistent DNA damage. Our results provide insight into the signaling pathways controlling Mdm2 destruction and further suggest that compromised regulation of Mdm2 results in attenuated p53 activity, thereby facilitating tumor progression.
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Affiliation(s)
- Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Alan Tseng
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Daming Gao
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Bo Zhai
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Qing Zhang
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Shavali Shaik
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Lixin Wan
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Xiaolu L. Ang
- Department of Pathology, Harvard Medical School, Boston, MA 02115
| | - Caroline Mock
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - Haoqiang Yin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
- Department of Biochemistry, Boston University Medical Center, Boston, MA 02118
| | - Jayne M. Stommel
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Steven Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Galit Lahav
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - John Asara
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Zhi-Xiong Jim Xiao
- Department of Biochemistry, Boston University Medical Center, Boston, MA 02118
| | - William G. Kaelin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - J. Wade Harper
- Department of Pathology, Harvard Medical School, Boston, MA 02115
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
- To whom correspondence should be addressed: Wenyi Wei, Ph.D., Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, Phone: (617)-735-2495;
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18
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Identification of BERP (brain-expressed RING finger protein) as a p53 target gene that modulates seizure susceptibility through interacting with GABA(A) receptors. Proc Natl Acad Sci U S A 2010; 107:11883-8. [PMID: 20543135 DOI: 10.1073/pnas.1006529107] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
p53 is a central player in responses to cellular stresses and a major tumor suppressor. The identification of unique molecules within the p53 signaling network can reveal functions of this important transcription factor. Here, we show that brain-expressed RING finger protein (BERP) is a gene whose expression is up-regulated in a p53-dependent manner in human cells and in mice. We generated BERP-deficient mice by gene targeting and demonstrated that they exhibit increased resistance to pentylenetetrazol-induced seizures. Electrophysiological and biochemical studies of cultured cortical neurons of BERP-deficient mice showed a decrease in the amplitude of GABA(A) receptor (GABA(A)R)-mediated miniature inhibitory postsynaptic currents as well as reduced surface protein expression of GABA(A)Rs containing the gamma2-subunit. However, BERP deficiency did not decrease GABA(A)Rgamma2 mRNA levels, raising the possibility that BERP may act at a posttranscriptional level to regulate the intracellular trafficking of GABA(A)Rs. Our results indicate that BERP is a unique p53-regulated gene and suggest a role for p53 within the central nervous system.
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Tuncbag N, Kar G, Gursoy A, Keskin O, Nussinov R. Towards inferring time dimensionality in protein-protein interaction networks by integrating structures: the p53 example. MOLECULAR BIOSYSTEMS 2010; 5:1770-8. [PMID: 19585003 PMCID: PMC2898629 DOI: 10.1039/b905661k] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Structural data, efficient structural comparison algorithms and appropriate datasets and filters can assist in getting an insight into time dimensionality in interaction networks; in predicting which interactions can and cannot co-exist; and in obtaining concrete predictions consistent with experiment.
Inspection of protein–protein interaction maps illustrates that a hub protein can interact with a very large number of proteins, reaching tens and even hundreds. Since a single protein cannot interact with such a large number of partners at the same time, this presents a challenge: can we figure out which interactions can occur simultaneously and which are mutually excluded? Addressing this question adds a fourth dimension into interaction maps: that of time. Including the time dimension in structural networks is an immense asset; time dimensionality transforms network node-and-edge maps into cellular processes, assisting in the comprehension of cellular pathways and their regulation. While the time dimensionality can be further enhanced by linking protein complexes to time series of mRNA expression data, current robust, network experimental data are lacking. Here we outline how, using structural data, efficient structural comparison algorithms and appropriate datasets and filters can assist in getting an insight into time dimensionality in interaction networks; in predicting which interactions can and cannot co-exist; and in obtaining concrete predictions consistent with experiment. As an example, we present p53-linked processes.
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Affiliation(s)
- Nurcan Tuncbag
- Koc University, Center for Computational Biology and Bioinformatics, College of Engineering, Rumelifeneri Yolu, 34450 Sariyer Istanbul, Turkey
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Vasileiou Z, Barlos K, Gatos D. Convergent solid-phase and solution approaches in the synthesis of the cysteine-rich Mdm2 RING finger domain. J Pept Sci 2010; 15:824-31. [PMID: 19824037 DOI: 10.1002/psc.1182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The RING finger domain of the Mdm2, located at the C-terminus of the protein, is necessary for regulation of p53, a tumor suppressor protein. The 48-residues long Mdm2 peptide is an important target for studying its interaction with small anticancer drug candidates. For the chemical synthesis of the Mdm2 RING finger domain, the fragment condensation on solid-phase and the fragment condensation in solution were studied. The latter method was performed using either protected or free peptides at the C-terminus as the amino component. Best results were achieved using solution condensation where the N-component was applied with the C-terminal carboxyl group left unprotected. The developed method is well suited for large-scale synthesis of Mdm2 RING finger domain, combining the advantages of both solid-phase and solution synthesis.
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Affiliation(s)
- Zoe Vasileiou
- Department of Chemistry, University of Patras, Patras, Greece
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21
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Mathijs K, Brauers KJJ, Jennen DGJ, Boorsma A, van Herwijnen MHM, Gottschalk RWH, Kleinjans JCS, van Delft JHM. Discrimination for Genotoxic and Nongenotoxic Carcinogens by Gene Expression Profiling in Primary Mouse Hepatocytes Improves with Exposure Time. Toxicol Sci 2009; 112:374-84. [DOI: 10.1093/toxsci/kfp229] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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22
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Kim SY, Hur W, Choi JE, Kim D, Wang JS, Yoon HY, Piao LS, Yoon SK. Functional characterization of human oncoprotein gankyrin in Zebrafish. Exp Mol Med 2009; 41:8-16. [PMID: 19287195 DOI: 10.3858/emm.2009.41.1.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Gankyrin is an oncoprotein containing seven ankyrin repeats that is overexpressed in hepatocellular carcinoma (HCC). Gankyrin binds to Mdm2, which results in accelerated ubiquitylation via degradation of p53, and it also plays an important role in cell proliferation. However, little is known about the relationships between p53 levels, cell proliferation, and gankyrin over-expression. In order to investigate the influence of gankyrin protein on p53 and Mdm2 in a zebrafish model, we injected human gankyrin (hgankyrin) containing expression vectors (pCS2-hgankyrin, pCS2- hgankyrin-EGFP) into zebrafish embryos. To measure p53 and Mdm2 expression in hgankyrin-injected embryos, RT-PCR, Northern blot and in-situ hybridization and BrdU immunostaining were used. In addition, to know the effect of hgankyrin on cell proliferation in vitro, cell viability assays such as MTT, trypan blue staining and RT-PCR following transfection of hgankyrin-containing vector into HEK 293 cell line were performed. In vivo results indicated that p53 mRNA levels decreased but those of Mdm2 were not decreased in the presence of hgankyrin. These results suggest that gankyrin downregulates p53 expression and not Mdm2 expression. In the study of cell proliferation, BrdU-positive cells were predominantly increased in the head and tail regions in hgankyrin-injected zebrafish. Additional in vitro studies using trypan blue staining and MTT assay showed that gankyrin-expressing HEK 293 cells proliferated at a faster rate, indicating that gankyrin promotes cell proliferation. Our results demonstrate that hgankyrin overexpression downregulates p53 expression and promotes cell proliferation in zebrafish. Gankyrin may play an important role in tumorigenesis via its effects on p53 and cell proliferation.
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Affiliation(s)
- So Yeon Kim
- Department of Internal Medicine and WHO Collaborating Center of Viral Hepatitis, The Catholic University of Korea, Seoul 137-701, Korea
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Fu W, Ma Q, Chen L, Li P, Zhang M, Ramamoorthy S, Nawaz Z, Shimojima T, Wang H, Yang Y, Shen Z, Zhang Y, Zhang X, Nicosia SV, Zhang Y, Pledger JW, Chen J, Bai W. MDM2 acts downstream of p53 as an E3 ligase to promote FOXO ubiquitination and degradation. J Biol Chem 2009; 284:13987-4000. [PMID: 19321440 DOI: 10.1074/jbc.m901758200] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Members of the FOXO (forkhead O) class of transcription factors are tumor suppressors that also control aging and organismal life span. Mammalian FOXO degradation is proteasome-mediated, although the ubiquitin E3 ligase for FOXO factors remains to be defined. We show that MDM2 binds to FOXO1 and FOXO3A and promotes their ubiquitination and degradation, a process apparently dependent on FOXO phosphorylation at AKT sites and the E3 ligase activity of MDM2. Binding of MDM2 to FOXO occurs through the region of MDM2 that directs its cellular trafficking and the forkhead box of FOXO1. MDM2 promotes the ubiquitination of FOXO1 in a cell-free system, and its knockdown by small interfering RNA causes accumulation of endogenous FOXO3A protein in cells and enhances the expression of FOXO target genes. In cells stably expressing a temperature-sensitive p53 mutant, activation of p53 by shifting to permissive temperatures leads to MDM2 induction and degradation of endogenous FOXO3A. These data suggest that MDM2 acts as an ubiquitin E3 ligase, downstream of p53, to regulate the degradation of mammalian FOXO factors.
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Affiliation(s)
- Wei Fu
- Department of Pathology and Cell Biology, University of South Florida College of Medicine, Tampa, Florida 33612, USA
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Hdm2 is regulated by K-Ras and mediates p53-independent functions in pancreatic cancer cells. Oncogene 2008; 28:709-20. [DOI: 10.1038/onc.2008.423] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Mu Z, Hachem P, Hensley H, Stoyanova R, Kwon HW, Hanlon AL, Agrawal S, Pollack A. Antisense MDM2 enhances the response of androgen insensitive human prostate cancer cells to androgen deprivation in vitro and in vivo. Prostate 2008; 68:599-609. [PMID: 18196567 PMCID: PMC2763092 DOI: 10.1002/pros.20731] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Antisense MDM2 oligonucleotide (AS-MDM2) sensitizes androgen sensitive LNCaP cells to androgen deprivation (AD) in vitro and in vivo. In this study, we investigated the effects of AS-MDM2 combined with AD on androgen resistant LNCaP (LNCaP-Res) and moderately androgen resistant bcl-2 overexpressing LNCaP (LNCaP-BST) cells. METHODS The LNCaP-Res cell line was generated by culturing LNCaP cells in medium containing charcoal-stripped serum for more than 1 year. Apoptosis was quantified in vitro by Annexin V staining and caspase 3 + 7 activity. For the in vivo studies, orthotopic tumor growth was monitored by magnetic resonance imaging (MRI). AS-MDM2 and the mismatch control were given by i.p. injection at doses of 25 mg/kg per day, 5 days/week for 15 days. RESULTS LNCaP-Res cells expressed high levels of androgen receptor (AR) and bcl-2, and displayed no growth inhibition to AD. AS-MDM2 caused significant reductions in MDM2 and AR expression, and increases in p53 and p21 expression in both cell lines. AS-MDM2 + AD resulted in the highest levels of apoptosis in vitro and tumor growth inhibition in vivo in both cell lines; although, these effects were less pronounced in LNCaP-BST cells. CONCLUSIONS AS-MDM2 + AD enhanced apoptotic cell death in vitro and tumor growth inhibition in vivo in androgen resistant cell lines. The action of AS-MDM2 + AD was influenced somewhat by bcl-2 expression as an isolated change (LNCaP-BST cells), but not when accompanied by other molecular changes associated with androgen insensitivity (LNCaP-Res cells). MDM2 knockdown has promise for the treatment of men with early hormone refractory disease.
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Affiliation(s)
- Zhaomei Mu
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Paul Hachem
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Harvey Hensley
- Department of Basic Science, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Radka Stoyanova
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Hae Won Kwon
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Alexandra L. Hanlon
- Department of Public Education, Temple University, Philadelphia, Pennsylvania
| | | | - Alan Pollack
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Correspondence to: Alan Pollack, MD, PhD, Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111.
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26
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O'Brien PM, Davies MJ, Scurry JP, Smith AN, Barton CA, Henderson MJ, Saunders DN, Gloss BS, Patterson KI, Clancy JL, Heinzelmann-Schwarz VA, Murali R, Scolyer RA, Zeng Y, Williams ED, Scurr L, Defazio A, Quinn DI, Watts CKW, Hacker NF, Henshall SM, Sutherland RL. The E3 ubiquitin ligase EDD is an adverse prognostic factor for serous epithelial ovarian cancer and modulates cisplatin resistance in vitro. Br J Cancer 2008; 98:1085-93. [PMID: 18349819 PMCID: PMC2275489 DOI: 10.1038/sj.bjc.6604281] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Despite a high initial response rate to first-line platinum/paclitaxel chemotherapy, most women with epithelial ovarian cancer relapse with recurrent disease that becomes refractory to further cytotoxic treatment. We have previously shown that the E3 ubiquitin ligase, EDD, a regulator of DNA damage responses, is amplified and overexpressed in serous ovarian carcinoma. Given that DNA damage pathways are linked to platinum resistance, the aim of this study was to determine if EDD expression was associated with disease recurrence and platinum sensitivity in serous ovarian cancer. High nuclear EDD expression, as determined by immunohistochemistry in a cohort of 151 women with serous ovarian carcinoma, was associated with an approximately two-fold increased risk of disease recurrence and death in patients who initially responded to first-line chemotherapy, independently of disease stage and suboptimal debulking. Although EDD expression was not directly correlated with relative cisplatin sensitivity of ovarian cancer cell lines, sensitivity to cisplatin was partially restored in platinum-resistant A2780-cp70 ovarian cancer cells following siRNA-mediated knockdown of EDD expression. These results identify EDD as a new independent prognostic marker for outcome in serous ovarian cancer, and suggest that pathways involving EDD, including DNA damage responses, may represent new therapeutic targets for chemoresistant ovarian cancer.
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Affiliation(s)
- P M O'Brien
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia .
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Wawrzynow B, Zylicz A, Wallace M, Hupp T, Zylicz M. MDM2 chaperones the p53 tumor suppressor. J Biol Chem 2007; 282:32603-12. [PMID: 17848574 DOI: 10.1074/jbc.m702767200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The murine double minute (mdm2) gene encodes an E3 ubiquitin ligase that plays a key role in the degradation of p53 tumor suppressor protein. Nevertheless recent data highlight other p53-independent functions of MDM2. Given that MDM2 protein binds ATP, can interact with the Hsp90 chaperone, plays a role in the modulation of transcription factors and protection and activation of DNA polymerases, and is involved in ribosome assembly and nascent p53 protein biosynthesis, we have evaluated and found MDM2 protein to possess an intrinsic molecular chaperone activity. MDM2 can substitute for the Hsp90 molecular chaperone in promoting binding of p53 to the p21-derived promoter sequence. This reaction is driven by recycling of MDM2 from the p53 complex, triggered by binding of ATP to MDM2. The ATP binding mutant MDM2 protein (K454A) lacks the chaperone activity both in vivo and in vitro. Mdm2 cotransfected in the H1299 cell line with wild-type p53 stimulates efficient p53 folding in vivo but at the same time accelerates the degradation of p53. MDM2 in which one of the Zn(2+) coordinating residues is mutated (C478S or C464A) blocks degradation but enhances folding of p53. This is the first demonstration that MDM2 possesses an intrinsic molecular chaperone activity, indicating that the ATP binding function of MDM2 can mediate its chaperone function toward the p53 tumor suppressor.
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Affiliation(s)
- Bartosz Wawrzynow
- International Institute of Molecular and Cell Biology in Warsaw, 4 Trojdena Street, Warsaw, Poland
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Zhou G, Zhai Y, Cui Y, Zhang X, Dong X, Yang H, He Y, Yao K, Zhang H, Zhi L, Yuan X, Qiu W, Zhang X, Shen Y, Qiang B, He F. MDM2 Promoter SNP309 Is Associated with Risk of Occurrence and Advanced Lymph Node Metastasis of Nasopharyngeal Carcinoma in Chinese Population. Clin Cancer Res 2007; 13:2627-33. [PMID: 17473193 DOI: 10.1158/1078-0432.ccr-06-2281] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Mouse double minute 2 (MDM2) is a key negative regulator of the p53 activity. Recently, a polymorphism in the MDM2 intronic promoter, SNP309, was shown to influence MDM2 expression and p53 activity. We examined whether the SNP309 was related to the risk of developing nasopharyngeal carcinoma (NPC) among Chinese populations. EXPERIMENTAL DESIGN We genotyped the SNP309 in two independent case-control populations in southern China, one is from Guangxi province (including 593 NPC patients and 480 controls) and the other is from Guangdong province (including 239 patients and 286 controls), by PCR direct sequencing. Multivariate logistic regression analysis was used to calculate adjusted odds ratio (OR) and 95% confidence interval (95% CI). RESULTS We observed that compared with the TT genotype, the genotypes containing G allele (GT + GG genotype) were associated with significant increased susceptibility to NPC in both Guangxi (OR, 1.43; 95% CI, 1.04-1.91) and Guangdong population (OR, 1.53; 95% CI, 1.00-2.36). When these two sample sets were combined, the OR of the GT + GG genotype developing NPC was 1.45 (95% CI, 1.12-1.85) compared with the TT genotype. Furthermore, compared with the TT genotype, the GT + GG genotype was also significantly associated with the advanced lymph node metastasis (OR, 1.84; 95% CI, 1.09-3.05). CONCLUSIONS Our findings suggest that the MDM2 SNP309 may be a risk factor for the occurrence and advanced neck lymph node metastasis of NPC in Chinese population.
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Affiliation(s)
- Gangqiao Zhou
- Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, China.
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29
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Gupta N, Chakrobarty A, Raman G, Banerjee G. Cloning and identification of EDD gene from ultraviolet-irradiated HaCaT cells. PHOTODERMATOLOGY PHOTOIMMUNOLOGY & PHOTOMEDICINE 2007; 22:278-84. [PMID: 17100734 DOI: 10.1111/j.1600-0781.2006.00251.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultraviolet (UV) radiation is one of the most important external stimuli that affects skin by inducing cancer, inflammation and cell death. To identify the regulation of genes regulated by UV during transformation, normal human keratinocyte cell line, HaCaT, was exposed to multiple doses of UVA+B (UVA - 150-200 mJ/cm2 and UVB - 15-20 mJ/cm2 x 6). Malignant transformation was confirmed by formation of colonies on soft agar and DNA methylation assay. To identify the genes involved in this process, random amplification of polymorphic DNA using RNA from unexposed and multiple exposed cells was performed after each exposure. A few up-regulated genes were identified, cloned and sequenced. One of the genes had homology to EDD (E3 identified by differential display) that was up-regulated at second exposure but was down-regulated in colony-forming cells (cells that received six or more exposures) as determined by RT-PCR. This is a progesterone-induced gene and progesterone treatment reduced the extent of colony formation on soft agar plate. It is possible that hormone therapy may have some effects on skin cancer in vivo.
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30
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Cheng TH, Cohen SN. Human MDM2 isoforms translated differentially on constitutive versus p53-regulated transcripts have distinct functions in the p53/MDM2 and TSG101/MDM2 feedback control loops. Mol Cell Biol 2006; 27:111-9. [PMID: 17060450 PMCID: PMC1800643 DOI: 10.1128/mcb.00235-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Proteins encoded by the mdm2 gene, which has a pivotal role in the regulation of growth and differentiation, exist principally in human and murine cells as two isoforms that migrate in gels as 75-kDa and 90-kDa proteins. There is limited understanding of the respective biological roles of these isoforms, their molecular nature, and their mechanism of formation. We report here that human p75(MDM2) is an N-terminally truncated mixture of protein isoforms produced by the initiation of translation at two distinct internal AUG codons. The p75(MDM2) doublets and p90(MDM2), which is the full-length MDM2 protein, are expressed in approximately equal amounts from transcripts initiated at the constitutive P1 promoter of mdm2. Unlike murine transcripts initiated at the p53-activated P2 promoter, human cell transcripts initiated at the P2 promoter preferentially produce p90(MDM2). The ubiquitin enzyme variant protein TSG101, which interacts functionally with MDM2 in an autoregulatory loop that parallels the p53/MDM2 feedback control loop, interferes with degradation of both isoforms; however, only p90(MDM2) promotes proteolysis of TSG101 and p53. Our results reveal the mechanism of formation of the principal MDM2 isoforms, the differential effects of p53 on the production of these isoforms, and the differential abilities of human MDM2 isoforms as regulators of the MDM2/TSG101 and p53/MDM2 feedback control loops.
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Affiliation(s)
- Tzu-Hao Cheng
- Stanford University School of Medicine, Department of Genetics, 300 Pasteur Drive, Stanford, CA 94305-5120, USA
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31
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Ma H, Hu Z, Zhai X, Wang S, Wang X, Qin J, Jin G, Liu J, Wang X, Wei Q, Shen H. Polymorphisms in the MDM2 promoter and risk of breast cancer: a case-control analysis in a Chinese population. Cancer Lett 2006; 240:261-7. [PMID: 16288830 DOI: 10.1016/j.canlet.2005.09.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 09/23/2005] [Accepted: 09/26/2005] [Indexed: 11/17/2022]
Abstract
MDM2 is a phosphoprotein that interacts with P53 and inhibits its activity. Recently, a T/G substitution (SNP309) in the promoter of MDM2 was identified and has been demonstrated to be associated with an increased MDM2 expression and a significantly earlier age of onset of several tumors, including breast cancer. To test the hypothesis that this functional variant in the MDM2 promoter is associated with risk of breast cancer, we conducted a molecular epidemiological study of 366 breast cancer cases (BC), 263 patients with benign breast diseases (BBD) and 605 cancer-free controls in China, in which we genotyped this T/G variant and another common insertion/deletion polymorphism (Del1518) in the MDM2 promoter and evaluated the associations between these two polymorphisms and breast cancer risk. We found that the variant allele frequencies of these two polymorphisms were not statistically different between the cases and controls (SNP309G: 0.500, 0.542, and 0.506 in BC, BBD, and controls, respectively, and Del1518-: 0.296, 0.308, and 0.297 in BC, BBD, and controls, respectively). Logistic regression analyses revealed that the variant genotypes of both MDM2 SNP309 and Del1518 polymorphisms were not significantly associated with risk of breast cancer (adjusted OR, 1.03; 95% CI, 0.74-1.42 for SNP309 TG and GG; and adjusted OR, 1.09; 95% CI, 0.83-1.43 for Del1518 +/- and -/-). These findings suggest that these two MDM2 promoter variants may not play a major role in the etiology of breast cancer.
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Affiliation(s)
- Hongxia Ma
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
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32
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Mayr C, Bund D, Schlee M, Bamberger M, Kofler DM, Hallek M, Wendtner CM. MDM2 is recognized as a tumor-associated antigen in chronic lymphocytic leukemia by CD8+ autologous T lymphocytes. Exp Hematol 2006; 34:44-53. [PMID: 16413390 DOI: 10.1016/j.exphem.2005.09.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 09/26/2005] [Accepted: 09/29/2005] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Tumor-associated antigens (TAA) are the basis for antigen-specific immunotherapy. The human homolog of the murine double-minute 2 oncoprotein (MDM2) is a putative TAA because it is overexpressed in several malignancies, including chronic lymphocytic leukemia (CLL) cells compared with normal B lymphocytes. PATIENTS AND METHODS Autologous, MDM2-specific human leukocyte antigen (HLA)-A2-restricted T cells were identified using interferon (IFN)-gamma-ELISPOT assays and HLA-A2/dimer-peptide staining after 4 weeks of in vitro culture. RESULTS Using native CLL cells as antigen-presenting cells (APCs), we demonstrate the generation of MDM2-specific T cells in 7/12 CLL patients that recognized specifically the MDM2-derived peptide MDM2(81-88) bound to HLA-A2-dimers while they were inactive against an unrelated MAGE-3 peptide (p = 0.002). After 4 weeks, up to 32.3% of the expanded CD8(+) T cells specifically recognized MDM2(81-88) by HLA-A2-dimer/peptide staining and up to 0.9% of all T cells expanded reacted specifically against this MDM2-derived peptide in the IFN-gamma-ELISPOT assay. If T cells were not expandable using native CLL cells as APC, leukemic cells were stimulated with CD40-ligand to increase the antigen-presenting capacity. This resulted in successful generation of MDM2-specific T cells in three of five remaining cases tested. Additionally, the factor that correlated best with successful generation of antigen-specific T cells in CLL patients was the ability of APCs to secrete IFN-gamma upon stimulation. CONCLUSION In summary, MDM2(81-88) was shown for the first time in humans to elicit a functional autologous immune response. MDM2 was demonstrated to be naturally processed and presented as TAA in primary human CLL cells enabling expansion of functional autologous tumor-specific T cells.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Antigen Presentation/immunology
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/immunology
- B-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cells, Cultured
- Epitopes/immunology
- Female
- Gene Expression Regulation, Leukemic/genetics
- Gene Expression Regulation, Leukemic/immunology
- HLA-A Antigens/immunology
- HLA-A2 Antigen
- Humans
- In Vitro Techniques
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Male
- Middle Aged
- Proto-Oncogene Proteins c-mdm2/genetics
- Proto-Oncogene Proteins c-mdm2/immunology
- RNA, Messenger/genetics
- RNA, Messenger/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- Christine Mayr
- KKG Gene Therapy, GSF-National Research Center for Environment and Health, Munich, Germany
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33
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Yang X, Wang J, Liu C, Grizzle WE, Yu S, Zhang S, Barnes S, Koopman WJ, Mountz JD, Kimberly RP, Zhang HG. Cleavage of p53-vimentin complex enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis of rheumatoid arthritis synovial fibroblasts. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:705-19. [PMID: 16127151 PMCID: PMC1698724 DOI: 10.1016/s0002-9440(10)62045-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Rheumatoid arthritis synovial fibroblasts (RASFs) contribute to arthritic cartilage degradation. Although RASFs are normally resistant to apoptosis, Apo2L/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based gene therapy has been successfully used in a mouse model of arthritis. We investigated this further by treating human RASFs with nontoxic doses of the proteasome inhibitor lactacystin. Treatment induced cytosolic accumulation of p53 and enhanced the susceptibility of RASFs to apoptosis mediated by TRAIL-R2 (DR5) but not Fas. A specific role for p53 in TRAIL-R2-mediated apoptosis was indicated by the ability of p53 siRNA to significantly reduce RASF apoptosis and by the reduced apoptosis of RASFs bearing p53 mutations on treatment with anti-DR5 antibody or anti-DR5 antibody plus lactacystin. p53 immunoprecipitation followed by mass spectrometry identified a vimentin-p53 complex, an interaction that was confirmed by reciprocal vimentin-p53 immunoprecipitation and by co-immunofluorescence. Interestingly, human caspase-4 cleaved human vimentin, and blockade of caspase-4 with a chemical inhibitor or with specific siRNA significantly inhibited TRAIL-R2-mediated apoptosis of RASFs. Furthermore, blockade of caspase-4 was paralleled by persistence of a cytosolic pattern of p53 and absence of p53 translocation to the nucleus. Taken together, our findings suggest a unique role for caspase-4 in cleaving vimentin and releasing cytosolic p53 for nuclear translocation, events that may regulate the sensitivity of RASFs to receptor-mediated apoptosis.
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Affiliation(s)
- Xinwen Yang
- Department of Medicine, University of Alabama at Birmingham, and the Birmingham Veterans Administration Medical Center, Birmingham, AL 35294-0007, USA
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34
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Kojima K, Konopleva M, Samudio IJ, Shikami M, Cabreira-Hansen M, McQueen T, Ruvolo V, Tsao T, Zeng Z, Vassilev LT, Andreeff M. MDM2 antagonists induce p53-dependent apoptosis in AML: implications for leukemia therapy. Blood 2005; 106:3150-9. [PMID: 16014563 PMCID: PMC1895324 DOI: 10.1182/blood-2005-02-0553] [Citation(s) in RCA: 298] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Although TP53 mutations are rare in acute myeloid leukemia (AML), inactivation of wild-type p53 protein frequently occurs through overexpression of its negative regulator MDM2 (murine double minute 2). Recently, small-molecule antagonists of MDM2, Nutlins, have been developed that inhibit the p53-MDM2 interaction and activate p53 signaling. Here, we study the effects of p53 activation by Nutlin-3 in AML cells. Treatment with MDM2 inhibitor triggered several molecular events consistent with induction of apoptosis: loss of mitochondrial membrane potential, caspase activation, phosphatidylserine externalization, and DNA fragmentation. There was a positive correlation in primary AML samples with wild-type p53 between baseline MDM2 protein levels and apoptosis induced by MDM2 inhibition. No induction of apoptosis was observed in AML samples harboring mutant p53. Colony formation of AML progenitors was inhibited in a dose-dependent fashion, whereas normal CD34+ progenitor cells were less affected. Mechanistic studies suggested that Nutlin-induced apoptosis was mediated by both transcriptional activation of proapoptotic Bcl-2 family proteins, and transcription-independent mitochondrial permeabilization resulting from mitochondrial p53 translocation. MDM2 inhibition synergistically enhanced cytotoxicity of cytosine arabinoside and doxorubicin in AML blasts but not in normal hematopoietic progenitor cells. p53 activation by targeting the p53-MDM2 interaction might offer a novel therapeutic strategy for AML that retain wild-type p53.
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Affiliation(s)
- Kensuke Kojima
- Section of Molecular Hematology and Therapy, Department of Blood and Marrow Transplantation, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 448, Houston, TX 77030, USA
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35
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Zhang Y, Fong CC, Wong MS, Tzang CH, Lai WP, Fong WF, Sui SF, Yang M. Molecular mechanisms of survival and apoptosis in RAW 264.7 macrophages under oxidative stress. Apoptosis 2005; 10:545-56. [PMID: 15909117 DOI: 10.1007/s10495-005-1885-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Organisms living in an aerobic environment are continuously exposed to reactive oxygen species (ROS). Apoptosis of cells can be induced by ROS and cells also develop negative feedback mechanisms to limit ROS induced cell death. In this study, RAW264.7 murine macrophage cells were treated with H(2)O(2) and cDNA microarray technique was used to produce gene expression profiles. We found that H(2)O(2) treatment caused up-regulation of stress, survival and apoptosis related genes, and down-regulation of growth and cell cycle promoting genes. Numerous genes of metabolism pathways showed special expression patterns under oxidative stress: glycolysis and lipid synthesis related genes were down-regulated whereas the genes of lipid catabolism and protein synthesis were up-regulated. We also identified several signaling molecules as ROS-responsive, including p53, Akt, NF-kappa B, ERK, JNK, p38, PKC and INF-gamma . They played important roles in the process of apoptosis or cell survival. Finally, an interactive pathway involved in cellular response to oxidative stress was proposed to provide some insight into the molecular events of apoptosis induced by ROS and the feedback mechanisms involved in cell survival.
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Affiliation(s)
- Y Zhang
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China
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36
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Kim E, Deppert W. Transcriptional activities of mutant p53: when mutations are more than a loss. J Cell Biochem 2005; 93:878-86. [PMID: 15449312 DOI: 10.1002/jcb.20271] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The dominant oncogenic properties of mutant p53 have been recognized as a phenomenon associated with tumor progression a long time ago, even before it was realized that the major function of wild type p53 is that of a tumor suppressor. Recent advances in this fascinating area in tumor cell biology reveal that the community of mutant p53 proteins is comprised of proteins that are extremely diverse both structurally and functionally, and elicit a multitude of cellular responses that not only are entirely distinct from those mediated by wild type p53, but also vary among different mutant p53 proteins. Aberrant regulation of transcription is one of the mechanisms underlying the ability of some mutant p53 proteins to act as oncogenic factors. Systematic analyses of the transcriptional activities of mutant p53 suggest that not the loss of transcriptional activity as such, but alterations of target DNA selectivity may be the driving force of mutant p53 specific transcription underlying the growth-promoting effects of mutant p53. This article focuses on mechanistic aspects of mutp53 "gain-of-function" with the emphasis on possible mechanisms underlying transcriptional activation by mutp53.
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Affiliation(s)
- Ella Kim
- Neuro-Oncology Group, Department of Neurosurgery, University of Schleswig-Holstein, Campus Luebeck, Germany
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37
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MacDuff DA, Neuberger MS, Harris RS. MDM2 can interact with the C-terminus of AID but it is inessential for antibody diversification in DT40 B cells. Mol Immunol 2005; 43:1099-108. [PMID: 16122802 DOI: 10.1016/j.molimm.2005.07.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Indexed: 01/10/2023]
Abstract
Activation-induced deaminase (AID) is essential for immunoglobulin gene diversification by the distinct processes of class switch recombination, somatic hypermutation and gene conversion. Most evidence indicates that AID triggers these reactions through the direct deamination of cytosine residues in the DNA. However, AID is predominantly cytoplasmic and the mechanism that directs it to the immunoglobulin loci remains elusive. Like its homolog APOBEC1, which requires at least one additional factor to efficiently edit APOB RNA, other proteins are likely to be required for the proper targeting of AID to the immunoglobulin loci. Here, we show that AID can interact with MDM2, an oncoprotein that shuttles between the nucleus and the cytoplasm and targets p53 for nuclear export and degradation. This interaction mapped to the carboxy-terminal region of AID that harbors a nuclear export sequence, suggesting that MDM2 may be involved in the nucleo-cytoplasmic trafficking of AID. We therefore assessed the role of MDM2 in immunoglobulin gene diversification by disrupting MDM2 in DT40, an avian B cell line that constitutively undergoes AID-dependent immunoglobulin gene diversification. The subcellular localization of AID was unaffected in MDM2-deficient DT40 cells. However, slight hyper-and hypo-conversion phenotypes were caused by MDM2-abrogation and overexpression, respectively. These observations suggested that MDM2 has the capacity to negatively regulate AID. Intriguingly, the same carboxy-terminal residues of AID were recently shown to be inessential for somatic hypermutation and immunoglobulin gene conversion but they were strictly required for class switch recombination.
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Affiliation(s)
- Donna A MacDuff
- University of Minnesota, Department of Biochemistry, Minneapolis, MN 55455, USA
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38
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Ma B, Pan Y, Gunasekaran K, Keskin O, Venkataraghavan RB, Levine AJ, Nussinov R. The contribution of the Trp/Met/Phe residues to physical interactions of p53 with cellular proteins. Phys Biol 2005; 2:S56-66. [PMID: 16204849 DOI: 10.1088/1478-3975/2/2/s06] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Dynamic molecular interaction networks underlie biological phenomena. Among the many genes which are involved, p53 plays a central role in networks controlling cellular life and death. It not only operates as a tumor suppressor, but also helps regulate hundreds of genes in response to various types of stress. To accomplish these functions as a guardian of the genome, p53 interacts extensively with both nucleic acids and proteins. This paper examines the physical interfaces of the p53 protein with cellular proteins. Previously, in the analysis of the structures of protein-protein complexes, we have observed that amino acids Trp, Met and Phe are important for protein-protein interactions in general. Here we show that these residues are critical for the many functions of p53. Several clusters of the Trp/Met/Phe residues are involved in the p53 protein-protein interactions. Phe19/Trp23 in the TA1 region extensively binds to the transcriptional factors and the MDM2 protein. Trp53/Phe54 in the TA2 region is crucial for transactivation and DNA replication. Met243 in the core domain interacts with 53BP1, 53BP2 and Rad 51 proteins. Met384/Phe385 in the C-terminal region interacts with the S100B protein and the Bromodomain of the CBP protein. Thus, these residues may assist in elucidating the p53 interactions when structural data are not available.
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Affiliation(s)
- Buyong Ma
- Basic Research Program, SAIC-Frederick, Inc., Laboratory of Experimental and Computational Biology, NCI-Frederick, Frederick, MD 21702, USA.
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Girnita L, Shenoy SK, Sehat B, Vasilcanu R, Girnita A, Lefkowitz RJ, Larsson O. {beta}-Arrestin is crucial for ubiquitination and down-regulation of the insulin-like growth factor-1 receptor by acting as adaptor for the MDM2 E3 ligase. J Biol Chem 2005; 280:24412-9. [PMID: 15878855 DOI: 10.1074/jbc.m501129200] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The insulin-like growth factor-1 receptor (IGF-1R) plays important roles in physiological growth and aging as well as promoting several crucial functions in cancer cells. However, the molecular mechanisms involved in expression and down-regulation of IGF-1R are still poorly understood. Here we provide evidence that beta-arrestin, otherwise known to be involved in the regulation of G protein-coupled receptors, serves as an adaptor to bring the oncoprotein E3 ubiquitin ligase MDM2 to the IGF-1R. In this way, beta-arrestin acts as a crucial component in the ubiquitination and down-regulation of the receptor. Both MDM2 and beta-arrestin co-immunoprecipitated with the IGF-1R. The beta-arrestin isoform 1 appeared to be more strongly associated with the receptor than isoform 2, and in a molecular context it was 4-fold more efficient in inducing polyubiquitination of IGF-1R, a reaction that required the presence of beta-arrestin and MDM2. Ligand stimulation accelerated IGF-1R ubiquitination. In mouse P6 cells (overexpressing human IGF-1R) absence of beta-arrestin 1, but not of beta-arrestin 2, blocked ubiquitination of IGF-1R. Conversely, in the two studied human melanoma cell lines both beta-arrestin isoforms seemed to be involved in IGF-1R ubiquitination. However, because depletion of beta-arrestin 1 almost completely eliminated degradation, and IGF-1 induced down-regulation of the receptor in these cells, whereas beta-arrestin 2 only had a partial effect, beta-arrestin 1 seems to the more important isoform in affecting the expression of IGF-1R. To our knowledge this is the first study demonstrating a defined molecular role of beta-arrestin with direct relevance to cell growth and cancer.
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Affiliation(s)
- Leonard Girnita
- Department of Oncology and Pathology, Division of Cellular and Molecular Tumor Pathology, Cancer Center Karolinska, R8:04, Karolinska Hospital, SE-171 76 Stockholm, Sweden
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40
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Huang W, Zhang J, Washington M, Liu J, Parant JM, Lozano G, Moore DD. Xenobiotic stress induces hepatomegaly and liver tumors via the nuclear receptor constitutive androstane receptor. Mol Endocrinol 2005; 19:1646-53. [PMID: 15831521 DOI: 10.1210/me.2004-0520] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The constitutive androstane receptor (CAR, NR1I3) is a central regulator of xenobiotic metabolism. CAR activation induces hepatic expression of detoxification enzymes and transporters and increases liver size. Here we show that CAR-mediated hepatomegaly is a transient, adaptive response to acute xenobiotic stress. In contrast, chronic CAR activation results in hepatocarcinogenesis. In both acute and chronic xenobiotic responses, hepatocyte DNA replication is increased and apoptosis is decreased. These effects are absent in CAR null mice, which are completely resistant to tumorigenic effects of chronic xenobiotic stress. In the acute response, direct up-regulation of Mdm2 expression by CAR contributes to both increased DNA replication and inhibition of p53-mediated apoptosis. These results demonstrate an essential role for CAR in regulating both liver homeostasis and tumorigenesis in response to xenobiotic stresses, and they also identify a specific molecular mechanism linking chronic environmental stress and tumor formation.
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Affiliation(s)
- Wendong Huang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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Hardie LJ, Darnton SJ, Wallis YL, Chauhan A, Hainaut P, Wild CP, Casson AG. p16 expression in Barrett's esophagus and esophageal adenocarcinoma: association with genetic and epigenetic alterations. Cancer Lett 2005; 217:221-30. [PMID: 15617840 DOI: 10.1016/j.canlet.2004.06.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 06/12/2004] [Accepted: 06/16/2004] [Indexed: 01/23/2023]
Abstract
Alteration of the p16 tumor suppressor gene has been implicated as a critical lesion in the molecular pathogenesis of esophageal adenocarcinoma. The aim of this study was to characterize the spectrum of p16 alterations in surgically resected esophageal tissues, comprising histologically normal esophageal squamous and gastric epithelia, premalignant Barrett's epithelia, and associated esophageal adenocarcinomas, and to explore associations between p16 mRNA expression and p16 mutations, deletions, promoter hypermethylation, p16 protein expression, and clinico-pathologic features for the same tissues. We have shown that while p16 mutations are uncommon (2%; 1/54), hypermethylation of the p16 promoter is detected in 43% (9/21) of histologically normal epithelia, in 77% (14/18) of associated Barrett's epithelia, and in 85% (18/21) of esophageal adenocarcinomas. However, p16 mRNA levels (relative to matched normal epithelia) were variable in Barrett's epithelia and adenocarcinomas, having no clear correlation with methylation status or other molecular and clinico-pathological parameters. These findings are consistent with a role for the p16 tumor suppressor gene early in the molecular progression of Barrett's epithelium to invasive esophageal adenocarcinoma, but do not support the notion that the detection of hypermethylation is systematically associated with low levels of expression.
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Affiliation(s)
- Laura J Hardie
- Molecular Epidemiology Unit and Health Services Research, School of Medicine, Algernon Firth Building, University of Leeds, Leeds LS2 9JT, UK.
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42
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Sphyris N, Harrison DJ. p53 deficiency exacerbates pleiotropic mitotic defects, changes in nuclearity and polyploidy in transdifferentiating pancreatic acinar cells. Oncogene 2005; 24:2184-94. [PMID: 15735758 DOI: 10.1038/sj.onc.1208249] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In a primary culture model for pancreatic acinar-ductal transdifferentiation, cells exhibited increased proliferation, changes in nuclearity and polyploidy. We identify the 'nucleus to centrosome' ratio of the progenitor cell, the dissemination of centrosomes at spindle poles and cytokinesis failure as critical determinants of mitosis outcome and centrosome inheritance. Abortive cytokinesis of mononuclear cells contributes to the binuclear cell pool, whereas enclosure of entire mitotic formations, within a single nuclear envelope, perpetuates polyploidization. Binuclear cell nuclei combine their genomes on a single metaphase plate, doubling descendant ploidy. Moreover, approximately 42% of binuclear and tetraploid cells assemble aberrant spindles with up to 8 centrosomes/poles. These phenotypes were exacerbated in p53-deficient cultures exhibiting increased S-phase entry, giant nuclei, multinucleation, multipolar mitoses and centrosome hyperamplification. The tendency of p53-proficient cells to spontaneously evade the tetraploidy checkpoint degenerates to uncontrolled polyploid progression in p53-deficient cultures, explaining why p53 abrogation alone rapidly descends to aneuploidy in this system. We detected constitutively nuclear mdm2, which may circumvent endogenous cell-cycle checkpoints, and pronounced accumulation of p21 and p27 in multinuclear cells and giant nuclei, consistent with roles in polyploidization. This in vitro model may recapitulate the processes underlying genomic instability in pancreatic tumours in vivo, and attests to the existence of a p53-dependent polyploidy checkpoint acting to limit the degree of polyploidization.
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Affiliation(s)
- Nathalie Sphyris
- Division of Pathology, School of Molecular and Clinical Medicine, The University of Edinburgh, Teviot Place, Edinburgh EH8 9AG, UK
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43
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Minsky N, Oren M. The RING domain of Mdm2 mediates histone ubiquitylation and transcriptional repression. Mol Cell 2005; 16:631-9. [PMID: 15546622 DOI: 10.1016/j.molcel.2004.10.016] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2004] [Revised: 08/29/2004] [Accepted: 09/03/2004] [Indexed: 10/25/2022]
Abstract
Histone modifications play a pivotal role in regulating transcription and other chromatin-associated processes. In yeast, histone H2B monoubiquitylation affects gene silencing. However, mammalian histone ubiquitylation remains poorly understood. We report that the Mdm2 oncoprotein, a RING domain E3 ubiquitin ligase known to ubiquitylate the p53 tumor suppressor protein, can interact directly with histones and promote in vitro monoubiquitylation of histones H2A and H2B. Moreover, Mdm2 induces H2B monoubiquitylation in vivo. Endogenous Mdm2 is tethered in vivo, presumably via p53, to chromatin comprising the p53-responsive p21(waf1) promoter, and Mdm2 overexpression enhances protein ubiquitylation in the vicinity of a p53 binding site within that promoter. Moreover, when recruited to a promoter in the absence of p53, Mdm2 can repress transcription dependently on its RING domain, suggesting that its E3 activity contributes to repression. Histone ubiquitylation may thus constitute a novel mechanism of transcriptional repression by Mdm2, possibly underlying some of its oncogenic activities.
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Affiliation(s)
- Neri Minsky
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
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Abstract
Many kinds of multifunctional regulatory proteins have been identified that perform distinct biochemical functions in the nucleus, the cytoplasm, or both. Here we describe the recent discovery by Hall et al. (2004) of a new type of multifunctional protein: a metabolic enzyme that doubles as a transcription factor. This enzyme, Arg5,6, functions as a catalytic enzyme in ornithine biosynthesis and also binds and regulates the promoters of nuclear and mitochondrial genes. It may also regulate precursor mRNA metabolism. We discuss how proteins that serve as both metabolic enzymes and transcription factors might have evolved.
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Affiliation(s)
- Anjana Bhardwaj
- Department of Immunology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4009, USA
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45
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Ougolkov A, Zhang B, Yamashita K, Bilim V, Mai M, Fuchs SY, Minamoto T. Associations Among -TrCP, an E3 Ubiquitin Ligase Receptor, -Catenin, and NF- B in Colorectal Cancer. J Natl Cancer Inst 2004; 96:1161-70. [PMID: 15292388 DOI: 10.1093/jnci/djh219] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The ubiquitin-proteasome pathway is important in regulating protein signaling pathways that are involved in tumorigenesis. beta-transducin repeat-containing proteins (beta-TrCP) are components of the ubiquitin ligase complex targeting beta-catenin and IkappaBalpha for proteasomal degradation and are thus a negative regulator of Wnt/beta-catenin signaling and a positive regulator of NF-kappaB signaling. We analyzed expression of beta-TrCP in colorectal cancers and its association with types of beta-catenin subcellular localization, an indirect measure of activation. METHODS Levels of beta-TrCP1 mRNA and protein were measured by quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively, in samples of tumor and normal tissues from 45 patients with colorectal cancer. Types of beta-catenin activation (diffuse or invasion edge) and NF-kappaB activation were examined by immunohistochemistry. Apoptosis was determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) assay. All statistical tests were two-sided. RESULTS Compared with the beta-TrCP1 levels in normal tissues, 25 (56%) of 45 tumors had increased beta-TrCP1 mRNA and protein levels. Of the 22 (49%) tumors with beta-catenin activation, 12 had the diffuse type (i.e., nuclear accumulation throughout the tumor) and 10 had the invasion edge type (i.e., nuclear accumulation predominantly in the tumor cells that formed the invasion edge). Increased beta-TrCP1 levels were statistically significantly associated with beta-catenin activation (P =.023) and decreased apoptosis (P =.035). beta-TrCP accumulated in the nuclei of tumor cells that contained increased levels of beta-TrCP1 mRNA and the active form of NF-kappaB. Higher levels of beta-TrCP1 mRNA were detected in primary tumors of patients who had metastases (0.960 arbitrary units, 95% confidence interval = 0.878 to 1.042) than in the tumors of patients who did not (0.722 arbitrary units, 95% confidence interval = 0.600 to 0.844; P =.016). CONCLUSION In colorectal cancer, increased expression of beta-TrCP1 is associated with activation of both beta-catenin and NF-kappaB, suggesting that the integration of these signaling pathways by increased beta-TrCP expression may contribute to an inhibition of apoptosis and tumor metastasis.
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Affiliation(s)
- Andrei Ougolkov
- Division of Diagnostic Molecular Oncology, Cancer Research Institute, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
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Mu Z, Hachem P, Agrawal S, Pollack A. Antisense MDM2 oligonucleotides restore the apoptotic response of prostate cancer cells to androgen deprivation. Prostate 2004; 60:187-96. [PMID: 15176048 DOI: 10.1002/pros.20044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Early in the malignant transformation of prostate epithelial cells, the apoptotic response to androgen deprivation (AD) is lost and the principle response is a slowing of cell growth. In this study, we tested whether interruption of MDM2 function using antisense MDM2 oligonucleotide (AS) affects the apoptotic response of prostate cancer cells to AD. METHODS Wild type LNCaP cells and MDM2-overexpressing (LNCaP-MST) cells were treated with AS alone or in combination with AD. Protein levels of MDM2, p53, and p21 were determined by Western blotting. Cell viability was measure by trypan blue staining. Apoptotic cell death was confirmed by cell morphological changes, annexin V/propidium iodide staining and caspase-3 + 7 activity. Overall cell survival was quantified by clonogenic assay. RESULTS AS inhibited MDM2 expression to a greater extent in LNCaP cells, as compared to LNCaP-MST cells. AS enhanced the expression of p53 and p21 in both cell lines. The growth inhibitory and cell death effects of AS + AD were generally greater than AS alone in LNCaP cells. Treatment of LNCaP cells with AS + AD for 72 hr caused a significant increase in cell death (66%) over AD alone (13%), AS alone (33%), or AD + AS + R1881 (34% with synthetic androgen replacement) that was attributable mainly to apoptosis. Clonogenic survival reflected the same pattern. CONCLUSIONS Our results suggest that the apoptotic response of prostate cancer to AD is strongly influenced by MDM2 expression. Antisense MDM2 has broad potential as a therapeutic agent to sensitize prostate cancer cells to AD therapy by enhancing apoptotic cell death.
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Affiliation(s)
- Zhaomei Mu
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
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47
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Dworakowska D, Jassem E, Jassem J, Peters B, Dziadziuszko R, Zylicz M, Jakóbkiewicz-Banecka J, Kobierska-Gulida G, Szymanowska A, Skokowski J, Roessner A, Schneider-Stock R. MDM2 gene amplification: a new independent factor of adverse prognosis in non-small cell lung cancer (NSCLC). Lung Cancer 2004; 43:285-95. [PMID: 15165086 DOI: 10.1016/j.lungcan.2003.09.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Revised: 09/08/2003] [Accepted: 09/11/2003] [Indexed: 01/10/2023]
Abstract
The prognostic impact of MDM2 amplification in non-small cell lung cancer (NSCLC) remains unknown. In this study, we investigated the occurrence of MDM2 amplification in surgically treated NSCLC patients. Molecular data were correlated with clinicopathological factors and evaluated for their prognostic value. The study group included 116 NSCLC patients who underwent pulmonary resection between 1996 and 1999. MDM2 amplification was assessed by real-time PCR using hybridization probe format on a LightCycler (Roche). The calculated ratio was a MDM2 value normalized to the amplification of the housekeeping gene phenylalaninhydroxylase (PAH). Survival curves were drawn according to the Kaplan-Meier method and compared with the use of the log-rank test. Multivariate analysis was based on Cox regression analysis. MDM2 amplification was found in 24 patients (21%). There was no relationship between MDM2 amplification and clinicopathological factors, such as sex, age and stage of disease, pT, pN, histology and tumor differentiation. Median disease-free survival (DFS) in patients with and without MDM2 amplification was 3 and 31 months, and 5-year DFS 24 and 33%, respectively (log-rank, P = 0.02). Likewise, median overall survival (OS) in patients with and without MDM2 amplification was 9 and 33 months, respectively, and 5-year OS 24 and 39%, respectively (log-rank, P = 0.01). The strong prognostic relevance of MDM2 amplification for both DFS and OS was confirmed in multivariate analysis (P < 0.01 for both comparisons). Our results suggest that MDM2 gene amplification analysis provides additional prognostic information in surgically treated NSCLC patients.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/pathology
- Carcinoma, Large Cell/genetics
- Carcinoma, Large Cell/metabolism
- Carcinoma, Large Cell/pathology
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- Carcinoma, Non-Small-Cell Lung/pathology
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Female
- Gene Amplification
- Humans
- Immunoenzyme Techniques
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Lung Neoplasms/pathology
- Male
- Middle Aged
- Nuclear Proteins/genetics
- Prognosis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-mdm2
- RNA, Messenger/genetics
- RNA, Neoplasm/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Survival Rate
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Affiliation(s)
- Dorota Dworakowska
- Department of Internal Medicine, Endocrinology and Haemostatic Disorders, Medical University of Gdańsk, Gdańsk, Poland
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Mu Z, Hachem P, Agrawal S, Pollack A. Antisense MDM2 sensitizes prostate cancer cells to androgen deprivation, radiation, and the combination. Int J Radiat Oncol Biol Phys 2004; 58:336-43. [PMID: 14751501 DOI: 10.1016/j.ijrobp.2003.09.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Antisense MDM2 (AS) sensitizes a variety of tumor cell types, including prostate cancer, to radiation and chemotherapy. We have previously described that AS enhances the apoptotic response to androgen deprivation (AD) and that this translates into a reduction in overall cell survival, as measured by clonogenic assay. Because AD + radiation (RT) is a key strategy for the treatment of men with high-risk prostate cancer, AS was tested for the ability to sensitize cells to the combination of AD+RT. METHODS AND MATERIALS LNCaP cells were cultured in vitro in either complete, androgen deprived (AD), or AD+R1881 (synthetic androgen) medium for 2-3 days before AS was administered. Radiation at 5 Gy was given 18-24 h later. Processing of the cells after RT was done at 3 h for Western blots, 24 and 48 h for trypan blue dye exclusion, 18 h for Annexin V staining by flow cytometric analysis, 18 h for Caspase 3+7 quantification by fluorometric assay, and immediately for clonogenic survival measured 12-14 days later. There were 18 treatment groups that were studied: lipofectin control, AS, antisense mismatch (ASM), AD, AD+R1881, and RT in all possible combinations. Statistical comparisons between groups were accomplished with one-way analysis of variance using the Bonferroni test, considering all 18 groups. RESULTS AS caused a reduction in MDM2 expression and an increase in p53 and p21 expression. Early cell death by trypan blue was found to be reflective of the apoptotic results by Annexin V and Caspase 3+7. AS caused a significant increase in apoptosis over the lipofectin control, AD, and RT controls. Apoptosis was further increased significantly by the addition of AD or RT to AS. When AS, AD, and RT were combined, there was a consistent increase in early cell death over AS+AD and AS+RT by all of the assay methods, although this increase was not significant. Overall cell death measured by clonogenic assay revealed synergistic cell killing of AS+RT beyond that of ASM+RT and RT alone, and AS+RT+AD beyond that of AS+RT, AS+RT+AD+R1881, ASM+RT+AD, and ASM+RT+AD+R1881. CONCLUSION AS sensitizes cells to AD, RT, and AD+RT and shows promise in the treatment of the full range of patients with prostate cancer. AS has the potential to sensitize the primary tumor to AD+RT and metastasis to AD.
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Affiliation(s)
- Zhaomei Mu
- Department of Radiation Oncology, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, PA 19111, USA
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Abstract
The interplay between Mdm2 and p53 represents one of the better-known paradigms of the relationship between an oncogene and a tumor suppressor gene. The Mdm2 protein is a key regulator of cell growth and death and plays a pivotal role in the transformation of normal cells into tumor cells, the hallmark of an oncogene. The primary role of Mdm2 under nonstressed conditions is to target the degradation ofthe tumor suppressor protein p53. In response to stress, however, p53 is not affected by Mdm2 and functions as a transcription factor that induces the transcription of Mdm2 as well as of genes involved in growth control or apoptosis. The effect of Mdm2 on the regulation of cell growth and death depends on p53 but also on a growing number of p53-independent targets. This overview summarizes our current understanding of Mdm2 and p53 regulation, function, and interaction in normal and tumor states.
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Affiliation(s)
- Dania Alarcon Vargas
- Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, New York 10029, USA
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50
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Sandra F. In reply to "Comment on: F. Sandra et al., The role of MDM2 in the proliferative activity of ameloblastoma", Oral Oncology 2002;38(2):153-7. Oral Oncol 2003; 39:745. [PMID: 12907216 DOI: 10.1016/s1368-8375(03)00099-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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