1
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Chen Q, Wu Y, Dai Z, Zhang Z, Yang X. Phosphorylation and specific DNA improved the incorporation ability of p53 into functional condensates. Int J Biol Macromol 2023; 230:123221. [PMID: 36634798 DOI: 10.1016/j.ijbiomac.2023.123221] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/26/2022] [Accepted: 01/07/2023] [Indexed: 01/11/2023]
Abstract
The transcription factor p53 acted as a critical tumor suppressor by activating the expression of various target genes to regulate diverse cellular responses. The phosphorylation of p53 influenced the binding of p53 to promotor-specific DNA and the choice of cell fate. In this study, we found that full-length wild-type p53 and pol II CTD could form heterotypic phase separation condensates in vitro. The heterotypic condensates of p53 and pol II CTD were mediated by electrostatic and hydrophobic interactions between pol II CTD and multiple domains of p53. The mobility of heterotypic p53 and pol II CTD droplets was significantly higher than that of p53 droplet. The phosphorylation promoted p53 to be recruited into pol II CTD droplets and transcription condensates. The specific DNA could further enhance the incorporation ability of p53 into functional condensates. Therefore, we proposed that the p53 droplet might be in a mediate state, the mutations resulting in p53 mutants with gain-of-function impelled the aggregate of p53, while the phosphorylation promoted p53 to be recruited into functional condensates as a client molecule to exert its function. This study might provide insights into the regulation mechanism that the phosphorylation and nuclei acid affected the phase behavior of p53.
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Affiliation(s)
- Qunyang Chen
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong Province 510006, PR China
| | - Yiping Wu
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong Province 510006, PR China
| | - Zhuojun Dai
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong Province 510006, PR China
| | - Zhuqing Zhang
- College of life sciences, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xiaorong Yang
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong Province 510006, PR China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, PR China.
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2
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Haronikova L, Bonczek O, Zatloukalova P, Kokas-Zavadil F, Kucerikova M, Coates PJ, Fahraeus R, Vojtesek B. Resistance mechanisms to inhibitors of p53-MDM2 interactions in cancer therapy: can we overcome them? Cell Mol Biol Lett 2021; 26:53. [PMID: 34911439 PMCID: PMC8903693 DOI: 10.1186/s11658-021-00293-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/05/2021] [Indexed: 12/13/2022] Open
Abstract
Since the discovery of the first MDM2 inhibitors, we have gained deeper insights into the cellular roles of MDM2 and p53. In this review, we focus on MDM2 inhibitors that bind to the p53-binding domain of MDM2 and aim to disrupt the binding of MDM2 to p53. We describe the basic mechanism of action of these MDM2 inhibitors, such as nutlin-3a, summarise the determinants of sensitivity to MDM2 inhibition from p53-dependent and p53-independent points of view and discuss the problems with innate and acquired resistance to MDM2 inhibition. Despite progress in MDM2 inhibitor design and ongoing clinical trials, their broad use in cancer treatment is not fulfilling expectations in heterogenous human cancers. We assess the MDM2 inhibitor types in clinical trials and provide an overview of possible sources of resistance to MDM2 inhibition, underlining the need for patient stratification based on these aspects to gain better clinical responses, including the use of combination therapies for personalised medicine.
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Affiliation(s)
- Lucia Haronikova
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic.
| | - Ondrej Bonczek
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
- Department of Medical Biosciences, Umea University, 901 87, Umea, Vasterbotten, Sweden
| | - Pavlina Zatloukalova
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
| | - Filip Kokas-Zavadil
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
| | - Martina Kucerikova
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Philip J Coates
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
| | - Robin Fahraeus
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic
- Department of Medical Biosciences, Umea University, 901 87, Umea, Vasterbotten, Sweden
- Inserm UMRS1131, Institut de Génétique Moléculaire, Université Paris 7, Hôpital St. Louis, 75010, Paris, France
| | - Borivoj Vojtesek
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic.
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3
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Visser H, Thomas AD. MicroRNAs and the DNA damage response: How is cell fate determined? DNA Repair (Amst) 2021; 108:103245. [PMID: 34773895 DOI: 10.1016/j.dnarep.2021.103245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/25/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022]
Abstract
It is becoming clear that the DNA damage response orchestrates an appropriate response to a given level of DNA damage, whether that is cell cycle arrest and repair, senescence or apoptosis. It is plausible that the alternative regulation of the DNA damage response (DDR) plays a role in deciding cell fate following damage. MicroRNAs (miRNAs) are associated with the transcriptional regulation of many cellular processes. They have diverse functions, affecting, presumably, all aspects of cell biology. Many have been shown to be DNA damage inducible and it is conceivable that miRNA species play a role in deciding cell fate following DNA damage by regulating the expression and activation of key DDR proteins. From a clinical perspective, miRNAs are attractive targets to improve cancer patient outcomes to DNA-damaging chemotherapy. However, cancer tissue is known to be, or to become, well adapted to DNA damage as a means of inducing chemoresistance. This frequently results from an altered DDR, possibly owing to miRNA dysregulation. Though many studies provide an overview of miRNAs that are dysregulated within cancerous tissues, a tangible, functional association is often lacking. While miRNAs are well-documented in 'ectopic biology', the physiological significance of endogenous miRNAs in the context of the DDR requires clarification. This review discusses miRNAs of biological relevance and their role in DNA damage response by potentially 'fine-tuning' the DDR towards a particular cell fate in response to DNA damage. MiRNAs are thus potential therapeutic targets/strategies to limit chemoresistance, or improve chemotherapeutic efficacy.
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Affiliation(s)
- Hartwig Visser
- Centre for Research in Biosciences, University of the West of England, Frenchay Campus, Bristol BS16 1QY, United Kingdom
| | - Adam D Thomas
- Centre for Research in Biosciences, University of the West of England, Frenchay Campus, Bristol BS16 1QY, United Kingdom.
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4
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Zhao CX, Zeng CM, Wang K, He QJ, Yang B, Zhou FF, Zhu H. Ubiquitin-proteasome system-targeted therapy for uveal melanoma: what is the evidence? Acta Pharmacol Sin 2021; 42:179-188. [PMID: 32601365 DOI: 10.1038/s41401-020-0441-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 12/22/2022] Open
Abstract
Uveal melanoma (UM) is a rare ocular tumor. The loss of BRCA1-associated protein 1 (BAP1) and the aberrant activation of G protein subunit alpha q (GNAQ)/G protein subunit alpha 11 (GNA11) contribute to the frequent metastasis of UM. Thus far, limited molecular-targeted therapies have been developed for the clinical treatment of UM. However, an increasing number of studies have revealed the close relationship between the ubiquitin proteasome system (UPS) and the malignancy of UM. UPS consists of a three-enzyme cascade, i.e. ubiquitin-activating enzymes (E1s); ubiquitin-conjugating enzymes (E2s); and ubiquitin-protein ligases (E3s), as well as 26S proteasome and deubiquitinases (DUBs), which work coordinately to dictate the fate of intracellular proteins through regulating ubiquitination, thus influencing cell viability. Due to the critical role of UPS in tumors, we here provide an overview of the crosstalk between UPS and the malignancy of UM, discuss the current UPS-targeted therapies in UM and highlight its potential in developing novel regimens for UM.
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5
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p21 WAF1/CIP1 promotes p53 protein degradation by facilitating p53-Wip1 and p53-Mdm2 interaction. Biochem Biophys Res Commun 2021; 543:23-28. [PMID: 33503543 DOI: 10.1016/j.bbrc.2021.01.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/20/2021] [Indexed: 12/28/2022]
Abstract
Downregulation of the p53 tumor suppressor in cancers is frequently accompanied by the upregulation of Wip1 (a phosphatase) and Mdm2 (an E3 ubiquitin ligase). Mdm2 binds and ubiquitinates p53, promoting its degradation by the proteasome. As the p53/Mdm2 interaction is alleviated by the phosphorylation of the serine-15 (S15) residue of p53, Wip1, which can directly dephosphorylate phospho-S15, facilitates the Mdm2-mediated degradation of p53. Here, we found that p21WAF1/CIP1, previously shown to bind p53 and Mdm2, reduces the cellular levels of p53 protein by decreasing its stability. This is accompanied by a decrease in p53-S15 phosphorylation levels. In agreement, p21 promotes the p53/Wip1 interaction. Additionally, p21 interacts with Wip1, forming a trimeric complex of p53, p21, and Wip1. Studies using a p21 deletion mutant that cannot bind p53 revealed that the p53/p21 complex is more efficient than p53 alone in facilitating the binding of p53 to Wip1 and Mdm2. These findings indicate that p21 is a novel negative regulator of p53 stability and therefore, may be used as a target to restore p53 activity by preventing the action of Wip1 and Mdm2 on p53.
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6
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Clonal Hematopoiesis and risk of Acute Myeloid Leukemia. Best Pract Res Clin Haematol 2019; 32:177-185. [PMID: 31203999 DOI: 10.1016/j.beha.2019.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 05/23/2019] [Indexed: 12/20/2022]
Abstract
Acute Myeloid Leukemia, the most common form of acute leukemia in adults, is an aggressive hematopoietic stem cell malignancy that is associated with significant morbidity and mortality. Though AML generally presents de novo, risk factors include exposure to chemotherapy and/or radiation, as well as both familial and acquired bone marrow failure syndromes. Clonal Hematopoiesis (CH) refers to an expansion of blood or marrow cells resulting from somatic mutations in leukemia-associated genes detected in individuals without cytopenias or hematological malignancies. While CH is considered part of normal ageing, CH is also significantly associated with cardiovascular disease, solid tumors, and hematological malignancies. In this review, we will discuss evidence linking CH with the development of AML, as well as describe challenges in and strategies for monitoring patients with high risk CH mutations.
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7
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Desai P, Roboz GJ. Clonal Hematopoiesis and therapy related MDS/AML. Best Pract Res Clin Haematol 2019; 32:13-23. [DOI: 10.1016/j.beha.2019.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 12/20/2022]
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8
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Rossi M, Colecchia D, Ilardi G, Acunzo M, Nigita G, Sasdelli F, Celetti A, Strambi A, Staibano S, Croce CM, Chiariello M. MAPK15 upregulation promotes cell proliferation and prevents DNA damage in male germ cell tumors. Oncotarget 2018; 7:20981-98. [PMID: 26988910 PMCID: PMC4991506 DOI: 10.18632/oncotarget.8044] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 01/29/2016] [Indexed: 12/09/2022] Open
Abstract
Germ cell tumors (GCT) are the most common malignancies in males between 15 and 35 years of age. Despite the high cure rate, achieved through chemotherapy and/or surgery, the molecular basis of GCT etiology is still largely obscure. Here, we show a positive correlation between MAPK15 (ERK8; ERK7) expression and specific GCT subtypes, with the highest levels found in the aggressive embryonal carcinomas (EC). Indeed, in corresponding cellular models for EC, MAPK15 enhanced tumorigenicity in vivo and promoted cell proliferation in vitro, supporting a role for this kinase in human GCT. At molecular level, we demonstrated that endogenous MAPK15 is necessary to sustain cell cycle progression of EC cells, by limiting p53 activation and preventing the triggering of p53-dependent mechanisms resulting in cell cycle arrest. To understand MAPK15-dependent mechanisms impinging on p53 activation, we demonstrate that this kinase efficiently protects cells from DNA damage. Moreover, we show that the ability of MAPK15 to control the autophagic process is necessary for basal management of DNA damage and for tumor formation controlled by the kinase. In conclusion, our findings suggest that MAPK15 overexpression may contribute to the malignant transformation of germ cells by controlling a “stress support” autophagic pathway, able to prevent DNA damage and the consequent activation of the p53 tumor suppressor. Moreover, in light of these results, MAPK15-specific inhibitors might represent new tools to enhance the therapeutic index of cytotoxic therapy in GCT treatment, and to increase the sensitivity to DNA-damaging drugs in other chemotherapy-resistant human tumors.
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Affiliation(s)
- Matteo Rossi
- Istituto Toscano Tumori (ITT), Core Research Laboratory (CRL), AOU Senese, Siena, Italy
| | - David Colecchia
- Istituto Toscano Tumori (ITT), Core Research Laboratory (CRL), AOU Senese, Siena, Italy.,Istituto di Fisiologia Clinica (IFC), Consiglio Nazionale delle Ricerche (CNR), Siena, Italy
| | - Gennaro Ilardi
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli "Federico II", Napoli, Italy
| | - Mario Acunzo
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Giovanni Nigita
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Federica Sasdelli
- Istituto Toscano Tumori (ITT), Core Research Laboratory (CRL), AOU Senese, Siena, Italy.,Istituto di Fisiologia Clinica (IFC), Consiglio Nazionale delle Ricerche (CNR), Siena, Italy
| | - Angela Celetti
- Istituto di Endocrinologia e Oncologia Sperimentale "G. Salvatore", CNR, Napoli, Italy
| | - Angela Strambi
- Istituto Toscano Tumori (ITT), Core Research Laboratory (CRL), AOU Senese, Siena, Italy
| | - Stefania Staibano
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli "Federico II", Napoli, Italy
| | - Carlo Maria Croce
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Mario Chiariello
- Istituto Toscano Tumori (ITT), Core Research Laboratory (CRL), AOU Senese, Siena, Italy.,Istituto di Fisiologia Clinica (IFC), Consiglio Nazionale delle Ricerche (CNR), Siena, Italy
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9
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Pechackova S, Burdova K, Benada J, Kleiblova P, Jenikova G, Macurek L. Inhibition of WIP1 phosphatase sensitizes breast cancer cells to genotoxic stress and to MDM2 antagonist nutlin-3. Oncotarget 2018; 7:14458-75. [PMID: 26883108 PMCID: PMC4924728 DOI: 10.18632/oncotarget.7363] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 01/29/2016] [Indexed: 02/07/2023] Open
Abstract
PP2C family serine/threonine phosphatase WIP1 acts as a negative regulator of the tumor suppressor p53 and is implicated in silencing of cellular responses to genotoxic stress. Chromosomal locus 17q23 carrying the PPM1D (coding for WIP1) is commonly amplified in breast carcinomas and WIP1 was proposed as potential pharmacological target. Here we employed a cellular model with knocked out PPM1D to validate the specificity and efficiency of GSK2830371, novel small molecule inhibitor of WIP1. We have found that GSK2830371 increased activation of the DNA damage response pathway to a comparable level as the loss of PPM1D. In addition, GSK2830371 did not affect proliferation of cells lacking PPM1D but significantly supressed proliferation of breast cancer cells with amplified PPM1D. Over time cells treated with GSK2830371 accumulated in G1 and G2 phases of the cell cycle in a p21-dependent manner and were prone to induction of senescence by a low dose of MDM2 antagonist nutlin-3. In addition, combined treatment with GSK2830371 and doxorubicin or nutlin-3 potentiated cell death through a strong induction of p53 pathway and activation of caspase 9. We conclude that efficient inhibition of WIP1 by GSK2830371 sensitizes breast cancer cells with amplified PPM1D and wild type p53 to chemotherapy.
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Affiliation(s)
- Sona Pechackova
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic
| | - Kamila Burdova
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic
| | - Jan Benada
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic
| | - Petra Kleiblova
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic.,Institute of Biochemistry and Experimental Oncology, Charles University in Prague, CZ-12853 Prague, Czech Republic
| | - Gabriela Jenikova
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic
| | - Libor Macurek
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220 Prague, Czech Republic
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10
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Pecháčková S, Burdová K, Macurek L. WIP1 phosphatase as pharmacological target in cancer therapy. J Mol Med (Berl) 2017; 95:589-599. [PMID: 28439615 PMCID: PMC5442293 DOI: 10.1007/s00109-017-1536-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/13/2017] [Accepted: 04/19/2017] [Indexed: 12/31/2022]
Abstract
DNA damage response (DDR) pathway protects cells from genome instability and prevents cancer development. Tumor suppressor p53 is a key molecule that interconnects DDR, cell cycle checkpoints, and cell fate decisions in the presence of genotoxic stress. Inactivating mutations in TP53 and other genes implicated in DDR potentiate cancer development and also influence the sensitivity of cancer cells to treatment. Protein phosphatase 2C delta (referred to as WIP1) is a negative regulator of DDR and has been proposed as potential pharmaceutical target. Until recently, exploitation of WIP1 inhibition for suppression of cancer cell growth was compromised by the lack of selective small-molecule inhibitors effective at cellular and organismal levels. Here, we review recent advances in development of WIP1 inhibitors and discuss their potential use in cancer treatment.
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Affiliation(s)
- Soňa Pecháčková
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic
| | - Kamila Burdová
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic
| | - Libor Macurek
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic.
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11
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Wen J, Lee J, Malhotra A, Nahta R, Arnold AR, Buss MC, Brown BD, Maier C, Kenney AM, Remke M, Ramaswamy V, Taylor MD, Castellino RC. WIP1 modulates responsiveness to Sonic Hedgehog signaling in neuronal precursor cells and medulloblastoma. Oncogene 2016; 35:5552-5564. [PMID: 27086929 PMCID: PMC5069081 DOI: 10.1038/onc.2016.96] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 12/28/2015] [Accepted: 01/22/2016] [Indexed: 12/18/2022]
Abstract
High-level amplification of the protein phosphatase PPM1D (WIP1) is present in a subset of medulloblastomas (MBs) that have an expression profile consistent with active Sonic Hedgehog (SHH) signaling. We found that WIP1 overexpression increased expression of Shh target genes and cell proliferation in response to Shh stimulation in NIH3T3 and cerebellar granule neuron precursor cells in a p53-independent manner. Thus, we developed a mouse in which WIP1 is expressed in the developing brain under control of the Neurod2 promoter (ND2:WIP1). The external granule layer (EGL) in early postnatal ND2:WIP1 mice exhibited increased proliferation and expression of Shh downstream targets. MB incidence increased and survival decreased when ND2:WIP1 mice were crossed with an Shh-activated MB mouse model. Conversely, Wip1 knockout significantly suppressed MB formation in two independent mouse models of Shh-activated MB. Furthermore, Wip1 knockdown or treatment with a WIP1 inhibitor suppressed the effects of Shh stimulation and potentiated the growth inhibitory effects of SHH pathway-inhibiting drugs in Shh-activated MB cells in vitro. This suggests an important cross-talk between SHH and WIP1 pathways that accelerates tumorigenesis and supports WIP1 inhibition as a potential treatment strategy for MB.
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Affiliation(s)
- Jing Wen
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Juhyun Lee
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Anshu Malhotra
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Rita Nahta
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Pharmacology, Atlanta, GA 30322, USA
| | - Amanda R. Arnold
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Meghan C. Buss
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Briana D. Brown
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Caroline Maier
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
| | - Anna M. Kenney
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Marc Remke
- Division of Neurosurgery, Arthur and Sonia Labatt Brain Tumour Research Center, and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Vijay Ramaswamy
- Division of Neurosurgery, Arthur and Sonia Labatt Brain Tumour Research Center, and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michael D. Taylor
- Division of Neurosurgery, Arthur and Sonia Labatt Brain Tumour Research Center, and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Robert C. Castellino
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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12
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Datta K, Suman S, Kumar S, Fornace AJ. Colorectal Carcinogenesis, Radiation Quality, and the Ubiquitin-Proteasome Pathway. J Cancer 2016; 7:174-83. [PMID: 26819641 PMCID: PMC4716850 DOI: 10.7150/jca.13387] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/01/2015] [Indexed: 12/12/2022] Open
Abstract
Adult colorectal epithelium undergoes continuous renewal and maintains homeostatic balance through regulated cellular proliferation, differentiation, and migration. The canonical Wnt signaling pathway involving the transcriptional co-activator β-catenin is important for colorectal development and normal epithelial maintenance, and deregulated Wnt/β-catenin signaling has been implicated in colorectal carcinogenesis. Colorectal carcinogenesis has been linked to radiation exposure, and radiation has been demonstrated to alter Wnt/β-catenin signaling, as well as the proteasomal pathway involved in the degradation of the signaling components and thus regulation of β-catenin. The current review discusses recent progresses in our understanding of colorectal carcinogenesis in relation to different types of radiation and roles that radiation quality plays in deregulating β-catenin and ubiquitin-proteasome pathway (UPP) for colorectal cancer initiation and progression.
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Affiliation(s)
- Kamal Datta
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC USA
| | - Shubhankar Suman
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC USA
| | - Santosh Kumar
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC USA
| | - Albert J Fornace
- 1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC USA.; 2. Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia
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13
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Tan YS, Ooi KK, Ang KP, Akim AM, Cheah YK, Halim SNA, Seng HL, Tiekink ERT. Molecular mechanisms of apoptosis and cell selectivity of zinc dithiocarbamates functionalized with hydroxyethyl substituents. J Inorg Biochem 2015; 150:48-62. [PMID: 26086852 DOI: 10.1016/j.jinorgbio.2015.06.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 06/03/2015] [Accepted: 06/06/2015] [Indexed: 10/23/2022]
Abstract
In the solid state each of three binuclear zinc dithiocarbamates bearing hydroxyethyl groups, {Zn[S2CN(R)CH2CH2OH]2}2 for R = iPr (1), CH2CH2OH (2), and Me (3), and an all alkyl species, [Zn(S2CNEt2)2]2 (4), features a centrosymmetric {ZnSCS}2 core with a step topology; both 1 and 3 were isolated as monohydrates. All compounds were broadly cytotoxic, specifically against human cancer cell lines compared with normal cells, with greater potency than cisplatin. Notably, some selectivity were indicated with 2 being the most potent against human ovarian carcinoma cells (cisA2780), and 4 being more cytotoxic toward multidrug resistant human breast carcinoma cells (MCF-7R), human colon adenocarcinoma cells (HT-29), and human lung adenocarcinoma epithelial cells (A549). Based on human apoptosis PCR-array analysis, caspase activities, DNA fragmentation, cell apoptotic assays, intracellular reactive oxygen species (ROS) measurements and human topoisomerase I inhibition, induction of apoptosis in HT-29 cells is demonstrated via both extrinsic and intrinsic pathways. Compounds 2-4 activate the p53 gene while 1 activates both p53 and p73. Cell cycle arrest at the S and G2/M phases correlates with inhibition of HT-29 cell growth. Cell invasion is also inhibited by 1-4 which is correlated with down-regulation of NF-κB.
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Affiliation(s)
- Yee Seng Tan
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kah Kooi Ooi
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Kok Pian Ang
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Abdah Md Akim
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Yoke-Kqueen Cheah
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
| | | | - Hoi-Ling Seng
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Biological Sciences, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia
| | - Edward R T Tiekink
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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14
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Richter M, Dayaram T, Gilmartin AG, Ganji G, Pemmasani SK, Van Der Key H, Shohet JM, Donehower LA, Kumar R. WIP1 phosphatase as a potential therapeutic target in neuroblastoma. PLoS One 2015; 10:e0115635. [PMID: 25658463 PMCID: PMC4319922 DOI: 10.1371/journal.pone.0115635] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/25/2014] [Indexed: 12/15/2022] Open
Abstract
The wild-type p53-induced phosphatase 1 (WIP1) is a serine/threonine phosphatase that negatively regulates multiple proteins involved in DNA damage response including p53, CHK2, Histone H2AX, and ATM, and it has been shown to be overexpressed or amplified in human cancers including breast and ovarian cancers. We examined WIP1 mRNA levels across multiple tumor types and found the highest levels in breast cancer, leukemia, medulloblastoma and neuroblastoma. Neuroblastoma is an exclusively TP53 wild type tumor at diagnosis and inhibition of p53 is required for tumorigenesis. Neuroblastomas in particular have previously been shown to have 17q amplification, harboring the WIP1 (PPM1D) gene and associated with poor clinical outcome. We therefore sought to determine whether inhibiting WIP1 with a selective antagonist, GSK2830371, can attenuate neuroblastoma cell growth through reactivation of p53 mediated tumor suppression. Neuroblastoma cell lines with wild-type TP53 alleles were highly sensitive to GSK2830371 treatment, while cell lines with mutant TP53 were resistant to GSK2830371. The majority of tested neuroblastoma cell lines with copy number gains of the PPM1D locus were also TP53 wild-type and sensitive to GSK2830371A; in contrast cell lines with no copy gain of PPM1D were mixed in their sensitivity to WIP1 inhibition, with the primary determinant being TP53 mutational status. Since WIP1 is involved in the cellular response to DNA damage and drugs used in neuroblastoma treatment induce apoptosis through DNA damage, we sought to determine whether GSK2830371 could act synergistically with standard of care chemotherapeutics. Treatment of wild-type TP53 neuroblastoma cell lines with both GSK2830371 and either doxorubicin or carboplatin resulted in enhanced cell death, mediated through caspase 3/7 induction, as compared to either agent alone. Our data suggests that WIP1 inhibition represents a novel therapeutic approach to neuroblastoma that could be integrated with current chemotherapeutic approaches.
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Affiliation(s)
- Mark Richter
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Tajhal Dayaram
- Department of Molecular Virology and Microbiology and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Aidan G. Gilmartin
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Gopinath Ganji
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | | | - Harjeet Van Der Key
- Platform Technology & Science, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Jason M. Shohet
- Texas Children’s Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lawrence A. Donehower
- Department of Molecular Virology and Microbiology and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (LAD); (RK)
| | - Rakesh Kumar
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
- * E-mail: (LAD); (RK)
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15
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Ali AY, Kim JY, Pelletier JF, Vanderhyden BC, Bachvarov DR, Tsang BK. Akt confers cisplatin chemoresistance in human gynecological carcinoma cells by modulating PPM1D stability. Mol Carcinog 2014; 54:1301-14. [PMID: 25154814 DOI: 10.1002/mc.22205] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/11/2014] [Accepted: 06/18/2014] [Indexed: 12/18/2022]
Abstract
Ovarian cancer (OVCA) and cervical cancer (CECA) are lethal gynecological malignancies. Cisplatin (CDDP) and platinum derivatives are first line chemotherapeutics and their resistance impedes successful treatment. Understanding the molecular dysregulation underlying chemoresistance is important in developing rational therapeutic strategies. We have established that Protein Phosphatase Magnesium-dependent 1 D (PPM1D) confers CDDP resistance in gynecological cancer cells by deactivating p53. However, whether CDDP regulates intra-cellular PPM1D localization and whether this regulation is different between chemosensitive and chemoresistant cancer cells is unknown. Moreover, whether Akt regulates PPM1D in the context of CDDP resistance has not been studied. To illustrate the role of PPM1D in gynecological cancer cell chemoresistance and its regulation by Akt we have demonstrated that: (a) CDDP induced PPM1D down-regulation through proteasomal degradation in sensitive CECA cells; (b) CDDP induced PPM1D nuclear localization in resistant CECA cells, and nuclear exclusion in sensitive CECA cells and OVCA xenografts; (c) Over-expression of active Akt in sensitive CECA cells stabilized PPM1D content through inhibition of CDDP-induced PPM1D down-regulation; (d) Inhibition of Akt activity in resistant OVCA cells leads to decreased PPM1D stability and CDDP-induced down-regulation in resistant CECA cells; and (e) PPM1D is highly expressed in human ovarian tumor subtypes and in a tissue microarray panel of human ovarian tumors. In conclusion, we have established that PPM1D plays an important role in promoting CDDP resistance and as a novel downstream target of Akt, PPM1D mediates its action in conferring CDDP resistance in gynecological cancer cells.
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Affiliation(s)
- Ahmed Y Ali
- Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Ji-Young Kim
- Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Jean-François Pelletier
- Département de Médecine Moleculaire, Faculté de Médecine, Université Laval, Québec City, Québec, Canada.,Centre de Recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec City, Québec, Canada
| | - Barbara C Vanderhyden
- Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Department of Obstetrics & Gynecology, University of Ottawa, Ottawa, Ontario, Canada.,Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Dimcho R Bachvarov
- Département de Médecine Moleculaire, Faculté de Médecine, Université Laval, Québec City, Québec, Canada.,Centre de Recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec City, Québec, Canada
| | - Benjamin K Tsang
- Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Obstetrics & Gynecology, University of Ottawa, Ottawa, Ontario, Canada.,Department of Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada.,World Class University (WCU) Biomodulation Major, Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
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16
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Dayaram T, Lemoine FJ, Donehower LA, Marriott SJ. Activation of WIP1 phosphatase by HTLV-1 Tax mitigates the cellular response to DNA damage. PLoS One 2013; 8:e55989. [PMID: 23405243 PMCID: PMC3566092 DOI: 10.1371/journal.pone.0055989] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 01/08/2013] [Indexed: 12/21/2022] Open
Abstract
Genomic instability stemming from dysregulation of cell cycle checkpoints and DNA damage response (DDR) is a common feature of many cancers. The cancer adult T cell leukemia (ATL) can occur in individuals infected with human T cell leukemia virus type 1 (HTLV-1), and ATL cells contain extensive chromosomal abnormalities, suggesting that they have defects in the recognition or repair of DNA damage. Since Tax is the transforming protein encoded by HTLV-1, we asked whether Tax can affect cell cycle checkpoints and the DDR. Using a combination of flow cytometry and DNA repair assays we showed that Tax-expressing cells exit G1 phase and initiate DNA replication prematurely following damage. Reduced phosphorylation of H2AX (γH2AX) and RPA2, phosphoproteins that are essential to properly initiate the DDR, was also observed in Tax-expressing cells. To determine the cause of decreased DDR protein phosphorylation in Tax-expressing cells, we examined the cellular phosphatase, WIP1, which is known to dephosphorylate γH2AX. We found that Tax can interact with Wip1 in vivo and in vitro, and that Tax-expressing cells display elevated levels of Wip1 mRNA. In vitro phosphatase assays showed that Tax can enhance Wip1 activity on a γH2AX peptide target by 2-fold. Thus, loss of γH2AX in vivo could be due, in part, to increased expression and activity of WIP1 in the presence of Tax. siRNA knockdown of WIP1 in Tax-expressing cells rescued γH2AX in response to damage, confirming the role of WIP1 in the DDR. These studies demonstrate that Tax can disengage the G1/S checkpoint by enhancing WIP1 activity, resulting in reduced DDR. Premature G1 exit of Tax-expressing cells in the presence of DNA lesions creates an environment that tolerates incorporation of random mutations into the host genome.
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Affiliation(s)
- Tajhal Dayaram
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Francene J. Lemoine
- Department of Biological Sciences, Northwestern State University of Louisiana, Natchitoches, Louisiana, United States of America
| | - Lawrence A. Donehower
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Susan J. Marriott
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Abstract
The MDM2 and MDMX (also known as HDMX and MDM4) proteins are deregulated in many human cancers and exert their oncogenic activity predominantly by inhibiting the p53 tumour suppressor. However, the MDM proteins modulate and respond to many other signalling networks in which they are embedded. Recent mechanistic studies and animal models have demonstrated how functional interactions in these networks are crucial for maintaining normal tissue homeostasis, and for determining responses to oncogenic and therapeutic challenges. This Review highlights the progress made and pitfalls encountered as the field continues to search for MDM-targeted antitumour agents.
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Affiliation(s)
- Mark Wade
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Via Adamello 16, 20139 Milan, Italy
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18
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Shi D, Gu W. Dual Roles of MDM2 in the Regulation of p53: Ubiquitination Dependent and Ubiquitination Independent Mechanisms of MDM2 Repression of p53 Activity. Genes Cancer 2012; 3:240-8. [PMID: 23150757 DOI: 10.1177/1947601912455199] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
MDM2 oncogenic protein is the principal cellular antagonist of the p53 tumor suppresser gene. p53 activity needs exquisite control to elicit appropriate responses to differential cellular stress conditions. p53 becomes stabilized and active upon various types of stresses. However, too much p53 is not beneficial to cells and causes lethality. At the steady state, p53 activity needs to be leashed for cell survival. Early studies suggested that the MDM2 oncoprotein negatively regulates p53 activity through the induction of p53 protein degradation. MDM2 serves as an E3 ubiquitin ligase of p53; it catalyzes polyubiquitination and subsequently induces proteasome degradation to downregulate p53 protein level. However, the mechanism by which MDM2 represses p53 is not a single mode. Emerging evidence reveals another cellular location of MDM2-p53 interaction. MDM2 is recruited to chromatin, specifically the p53 responsive promoter regions, in a p53 dependent manner. MDM2 is proposed to directly inhibit p53 transactivity at chromatin. This article provides an overview of the mechanism by which p53 is repressed by MDM2 in both ubiquitination dependent and ubiquitination independent pathways.
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Affiliation(s)
- Dingding Shi
- Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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19
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Doucette TA, Yang Y, Pedone C, Kim JYH, Dubuc A, Northcott PD, Taylor MD, Fults DW, Rao G. WIP1 enhances tumor formation in a sonic hedgehog-dependent model of medulloblastoma. Neurosurgery 2012; 70:1003-10; discussion 1010. [PMID: 22037313 DOI: 10.1227/neu.0b013e31823e5332] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND A significant number of medulloblastomas (MBs) originate from abnormal activation of the sonic hedgehog/patched (SHH/PTC) signaling pathway. Although p53 deficiency enhances tumor formation in mice, inactivation of the p53 gene is seen in a minority of MBs. Wild-type p53-induced phosphatase 1 (WIP1) downregulates p53 expression and has been shown to be overexpressed in MBs. OBJECTIVE We tested the hypothesis that overexpression of WIP1 enhances tumor formation in an SHH-dependent model of MB. METHODS We used the RCAS/Ntv-a system to study the effect of WIP1 in vitro and in vivo. We transfected A375-TVA cells with RCAS-WIP1 and then exposed these cells to cisplatin to determine the effect on p53 expression. We modeled ectopic WIP1 expression independently and in combination with SHH in the cerebella of newborn mice to assess the effect on tumor formation. Mice were observed for 12 weeks or until neurological symptoms developed. The brains were examined for tumor formation. RESULTS A375-TVA cells infected with RCAS-WIP1 demonstrated reduced p53 expression after exposure to cisplatin compared with controls. We detected tumors in 12 of 35 mice (34%) injected with RCAS-WIP1 and RCAS-SHH. Tumors were detected in 3 of 40 mice (8%) injected with RCAS-SHH alone. The difference in tumor formation rates was significant (χ(2) test, P = < .01). Tumors did not form in mice injected with RCAS-WIP1 alone. CONCLUSION We show that ectopic expression of WIP1 cooperates with SHH to enhance formation of MB, although it is insufficient to induce tumors independently. Our results verify the role of WIP1 in MB formation and provide a crucial link to the inactivation of p53 in MBs.
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Affiliation(s)
- Tiffany A Doucette
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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20
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Abstract
p53 plays an important role in the regulation of the cell cycle, DNA repair, and apoptosis and is an attractive cancer therapeutic target. Mdm2 and Mdmx are recognized as the main p53 negative regulators. Although it is still unknown why Mdm2 and Mdmx both are required for p53 degradation, a model has been proposed whereby these two proteins function independent of one another; Mdm2 acts as an E3 ubiquitin ligase that catalyzes the ubiquitination of p53 for degradation, whereas Mdmx inhibits p53 by binding to and masking the transcriptional activation domain of p53, without causing its degradation. However, Mdm2 and Mdmx have been shown to function collaboratively. In fact, recent studies have pointed to a more important role for an Mdm2/Mdmx co-regulatory mechanism for p53 regulation than previously thought. In this review, we summarize current progress in the field about the functional and physical interactions between Mdm2 and Mdmx, their individual and collaborative roles in controlling p53, and inhibitors that target Mdm2 and Mdmx as a novel class of anticancer therapeutics.
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Affiliation(s)
- Dongsheng Pei
- Laboratory of Biological Cancer Therapy, Xuzhou Medical College, Xuzhou, China
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21
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Han C, Wan G, Langley RR, Zhang X, Lu X. Crosstalk between the DNA damage response pathway and microRNAs. Cell Mol Life Sci 2012; 69:2895-906. [PMID: 22430204 PMCID: PMC11115143 DOI: 10.1007/s00018-012-0959-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 12/11/2022]
Abstract
MicroRNAs (miRNAs) are a family of small, non-coding RNAs that control gene expression at the post-transcriptional level by destabilizing and inhibiting translation of their target messenger RNAs. MiRNAs are involved in the regulation of a number of fundamental biological processes, and their dysregulation is thought to contribute to several disease processes. Emerging evidence suggests that miRNAs also play a critical role in protecting the heritable genome by contributing to the regulation of the DNA damage response. Consequently, much recent investigative effort has been directed towards an improved understanding of how miRNAs are regulated in response to DNA damage. In this review, we discuss the most recent findings regarding the regulation of miRNA expression and the functional roles of miRNAs in the DNA damage response.
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Affiliation(s)
- Cecil Han
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Guohui Wan
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Robert R. Langley
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Xinna Zhang
- Department of Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Xiongbin Lu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
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22
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Carson C, Omolo B, Chu H, Zhou Y, Sambade MJ, Peters EC, Tompkins P, Simpson DA, Thomas NE, Fan C, Sarasin A, Dessen P, Shields JM, Ibrahim JG, Kaufmann WK. A prognostic signature of defective p53-dependent G1 checkpoint function in melanoma cell lines. Pigment Cell Melanoma Res 2012; 25:514-26. [PMID: 22540896 DOI: 10.1111/j.1755-148x.2012.01010.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Melanoma cell lines and normal human melanocytes (NHM) were assayed for p53-dependent G1 checkpoint response to ionizing radiation (IR)-induced DNA damage. Sixty-six percent of melanoma cell lines displayed a defective G1 checkpoint. Checkpoint function was correlated with sensitivity to IR with checkpoint-defective lines being radio-resistant. Microarray analysis identified 316 probes whose expression was correlated with G1 checkpoint function in melanoma lines (P≤0.007) including p53 transactivation targets CDKN1A, DDB2, and RRM2B. The 316 probe list predicted G1 checkpoint function of the melanoma lines with 86% accuracy using a binary analysis and 91% accuracy using a continuous analysis. When applied to microarray data from primary melanomas, the 316 probe list was prognostic of 4-yr distant metastasis-free survival. Thus, p53 function, radio-sensitivity, and metastatic spread may be estimated in melanomas from a signature of gene expression.
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Affiliation(s)
- Craig Carson
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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23
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Buss MC, Read TA, Schniederjan MJ, Gandhi K, Castellino RC. HDM2 promotes WIP1-mediated medulloblastoma growth. Neuro Oncol 2012; 14:440-58. [PMID: 22379189 DOI: 10.1093/neuonc/nos001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Medulloblastoma is the most common malignant childhood brain tumor. The protein phosphatase and oncogene WIP1 is over-expressed or amplified in a significant number of primary human medulloblastomas and cell lines. In the present study, we examine an important mechanism by which WIP1 promotes medulloblastoma growth using in vitro and in vivo models. Human cell lines and intracerebellar xenografted animal models were used to study the role of WIP1 and the major TP53 regulator, HDM2, in medulloblastoma growth. Stable expression of WIP1 enhances growth of TP53 wild-type medulloblastoma cells, compared with cells with stable expression of an empty-vector or mutant WIP1. In an animal model, WIP1 enhances proliferation and reduces the survival of immunodeficient mice bearing intracerebellar xenografted human medulloblastoma cells. Cells with increased WIP1 expression also exhibit increased expression of HDM2. HDM2 knockdown or treatment with the HDM2 inhibitor Nutlin-3a, the active enantomer of Nutlin-3, specifically inhibits the growth of medulloblastoma cells with increased WIP1 expression. Nutlin-3a does not affect growth of medulloblastoma cells with stable expression of an empty vector or of mutant WIP1. Knockdown of WIP1 or treatment with the WIP1 inhibitor CCT007093 results in increased phosphorylation of known WIP1 targets, reduced HDM2 expression, and reduced growth specifically in WIP1 wild-type and high-expressing medulloblastoma cells. Combined WIP1 and HDM2 inhibition is more effective than WIP1 inhibition alone in blocking growth of WIP1 high-expressing medulloblastoma cells. Our preclinical study supports a role for therapies that target WIP1 and HDM2 in the treatment of medulloblastoma.
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Affiliation(s)
- Meghan C Buss
- Department of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Atlanta, Georgia, USA
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24
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Park JY, Song JY, Kim HM, Han HS, Seol HS, Jang SJ, Choi J. p53-Independent expression of wild-type p53-induced phosphatase 1 (Wip1) in methylmethane sulfonate-treated cancer cell lines and human tumors. Int J Biochem Cell Biol 2012; 44:896-904. [PMID: 22405851 DOI: 10.1016/j.biocel.2012.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 02/08/2012] [Accepted: 02/15/2012] [Indexed: 01/03/2023]
Abstract
Wild-type p53-induced phosphatase 1 (Wip1, PPM1D) is induced by p53 in response to various stressors and dephosphorylates cellular target proteins involved in DNA repair and cell cycle checkpoint pathways. The Wip1 gene is frequently amplified or overexpressed in human cancers, promoting tumor growth by switching off major checkpoint kinases and p53. To explore wild-type p53-independent Wip1 induction, Wip1 promoter activity and its transcript level were evaluated by luciferase assay and real-time PCR, after methylmethane sulfonate (MMS) treatment in breast cancer cell lines and p53-null cell lines. Wip1 promoter activities in response to UV irradiation and various anti-cancer agents were compared between wild-type and a p53-response element (p53RE) mutated construct. Wip1 expression and its effects were examined in primary non-small cell lung cancer (NSCLC) and colon tumor cells by using Wip1-specific siRNA. MMS induced Wip1 promoter activity in Hs578T, MDA-MB-231, and SK-BR-3 cells expressing DNA binding-deficient p53 mutants. A549-E6 and HCT116 (p53(-/-)) cells retained substantial Wip1 induction. Wip1 promoter activity was reduced, but not eliminated, in cells expressing a promoter containing a mutated p53-response element. Wip1 induction was not blocked by SB202190 or SP600125. MMS increased Wip1 expression in primary non-small cell lung cancer cells expressing a p53 R175H mutant. Our data indicate that Wip1 is induced in the absence of functional p53, like p38 MAPK and JNK, as a stress response terminator.
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Affiliation(s)
- Ji-Young Park
- Department of Pathology, University of Ulsan College of Medicine, Asan Medical center, Seoul, Republic of Korea
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25
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MdmX is required for p53 interaction with and full induction of the Mdm2 promoter after cellular stress. Mol Cell Biol 2012; 32:1214-25. [PMID: 22290440 DOI: 10.1128/mcb.06150-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The activity of the tumor suppressor p53 is tightly controlled by its main negative regulator, Mdm2, which inhibits p53's transcriptional activity and targets it for degradation via the proteasome pathway. The closely related Mdm2 homolog, MdmX, is also considered to be a general inhibitor of transactivation by p53, through binding to the p53 activation domain. We show here that, unexpectedly, upon DNA damage and ribosomal stress, MdmX plays a positive role in p53-mediated activation of the Mdm2 gene, but not of numerous other p53 target genes including p21. Downregulation of MdmX results in lower levels of mature and nascent Mdm2 transcripts following cellular stress. This correlates with a longer p53 half-life following DNA damage. In vitro, Mdm2 inhibits the binding of p53 to DNA to a much greater extent than does MdmX, although MdmX does not stimulate p53 interaction with Mdm2 promoter DNA. Strikingly, however, MdmX is required for optimal p53 binding to the Mdm2 promoter in vivo. Thus, we have described a new mechanism by which MdmX can suppress p53, which is through transcriptional activation of p53's principal negative regulator, Mdm2.
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26
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Wang P, Rao J, Yang H, Zhao H, Yang L. Wip1 over-expression correlated with TP53/p14(ARF) pathway disruption in human astrocytomas. J Surg Oncol 2011; 104:679-84. [PMID: 21695702 DOI: 10.1002/jso.22004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 05/31/2011] [Indexed: 12/16/2022]
Abstract
PURPOSE Wip1 over-expression inhibits p53 function and reduces selection for TP53 mutations during cancer progression. To clarify the correlation of Wip1 with TP53/p14(ARF) pathway disruption in astyrocytomas, the expression of Wip1 and TP53/p14(ARF) pathway alterations have been investigated. METHODS Tumor samples of 52 patients of astrocytomas were examined for TP53 mutations, p14(ARF) expression, and Wip1 expression. Direct sequencing of region from exons 5 to 8 of the TP53 gene was performed on the genomic DNA in each sample. The DNA methylation states of the CpG islands of the p14(ARF) gene were determined by MSP. The expression of Wip1 was analyzed by real-time quantitative PCR, Western blot, and immunohistochemical staining. RESULTS Disruption of the TP53/p14ARF pathway was detected in 57.7% of samples. Among 22 cases without TP53 and p14ARF alterations, 11 (50%) had Wip1 mRNA over-expression. In tumors with wild-type TP53 and p14ARF, Wip1 mRNA was over-expressed only 1 case out of 30 (3.3%). Higher levels of Wip1 were associated with TP53 mutations but not with lower levels of expression of p14(ARF) or aberrant promoter hypermethylation of the p14(ARF) gene. CONCLUSION Wip1 is selectively over-expressed in astyrocytomas without alterations in TP53 or p14(ARF). Wip1 may inhibit the TP53/p14(ARF) pathway.
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Affiliation(s)
- Peng Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
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27
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Tuna M, Smid M, Martens JWM, Foekens JA. Prognostic value of acquired uniparental disomy (aUPD) in primary breast cancer. Breast Cancer Res Treat 2011; 132:189-96. [DOI: 10.1007/s10549-011-1579-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 05/07/2011] [Indexed: 11/30/2022]
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Aging and chronic DNA damage response activate a regulatory pathway involving miR-29 and p53. EMBO J 2011; 30:2219-32. [PMID: 21522133 DOI: 10.1038/emboj.2011.124] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 03/30/2011] [Indexed: 12/23/2022] Open
Abstract
Aging is a multifactorial process that affects most of the biological functions of the organism and increases susceptibility to disease and death. Recent studies with animal models of accelerated aging have unveiled some mechanisms that also operate in physiological aging. However, little is known about the role of microRNAs (miRNAs) in this process. To address this question, we have analysed miRNA levels in Zmpste24-deficient mice, a model of Hutchinson-Gilford progeria syndrome. We have found that expression of the miR-29 family of miRNAs is markedly upregulated in Zmpste24(-/-) progeroid mice as well as during normal aging in mouse. Functional analysis revealed that this transcriptional activation of miR-29 is triggered in response to DNA damage and occurs in a p53-dependent manner since p53(-/-) murine fibroblasts do not increase miR-29 expression upon doxorubicin treatment. We have also found that miR-29 represses Ppm1d phosphatase, which in turn enhances p53 activity. Based on these results, we propose the existence of a novel regulatory circuitry involving miR-29, Ppm1d and p53, which is activated in aging and in response to DNA damage.
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Wang P, Rao J, Yang H, Zhao H, Yang L. PPM1D silencing by lentiviral-mediated RNA interference inhibits proliferation and invasion of human glioma cells. ACTA ACUST UNITED AC 2011; 31:94-99. [PMID: 21336731 DOI: 10.1007/s11596-011-0157-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Indexed: 12/20/2022]
Abstract
To construct a lentiviral shRNA vector targeting human protein phosphatase 1D magnesium-dependent (PPM1D) gene and detect its effectiveness of gene silencing in human gliomas, specific siRNA targets with short hairpin frame were designed and synthesized. DNA oligo was cloned into the pFU-GW-iRNA lentiviral expression vector, and then PCR and sequencing analyses were conducted to verify the constructs. After the verified plasmids were transfected into 293T cells, the lentivirus was produced and the titer of virus was determined. Real-time quantitative PCR and Western blot were performed to detect the PPM1D expression level in the infected glioma cells. PCR and Western blot analyses revealed the optimal interfering target, and the virus with a titer of 6×10(8) TU/mL was successfully packaged. The PPM1D expression in human glioma cells was knocked down at both mRNA and protein levels by virus infection. The expression of PPM1D mRNA and protein was decreased by 76.3% and 87.0% respectively as compared with control group. The multiple functions of human glioma cells after PPM1D RNA interference were detected by flow cytometry and cell counting kit-8 (CCK-8). Efficient down-regulation of PPM1D resulted in significantly increased cell apoptosis and reduced cell proliferation and invasion potential in U87-MG cells. We have successfully constructed the lentiviral shRNA expression vector capable of stable PPM1D gene silencing at both mRNA and protein levels in glioma cells. And our data gave evidence that the reduced cell growth observed after PPM1D silencing in glioma cells was at least partly due to increased apoptotic cell death.
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Affiliation(s)
- Peng Wang
- Department of Neurosurgery, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080, China
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jing Rao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Haifeng Yang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hongyang Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Lin Yang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Wang Z, Li B. Mdm2 links genotoxic stress and metabolism to p53. Protein Cell 2011; 1:1063-72. [PMID: 21213101 DOI: 10.1007/s13238-010-0140-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 11/30/2010] [Indexed: 01/06/2023] Open
Abstract
Mouse double minute 2 (Mdm2) gene was isolated from a cDNA library derived from transformed mouse 3T3 cells, and was classified as an oncogene as it confers 3T3 and Rat2 cells tumorigenicity when overexpressed. It encodes a nucleocytoplasmic shuttling ubiquitin E3 ligase, with its main target being tumor suppressor p53, which is mutated in more than 50% of human primary tumors. Mdm2's oncogenic activity is mainly mediated by p53, which is activated by various stresses, especially genotoxic stress, via Atm (ataxia telangiectasia mutated) and Atr (Atm and Rad3-related). Activated p53 inhibits cell proliferation, induces apoptosis or senescence, and maintains genome integrity. Mdm2 is also a target gene of p53 transcription factor. Thus, Mdm2 and p53 form a feedback regulatory loop. External and internal cues, through multiple signaling pathways, can act on Mdm2 to regulate p53 levels and cell proliferation, death, and senescence. This review will focus on how Mdm2 is regulated under genotoxic stress, and by the Akt1-mTOR-S6K1 pathway that is activated by insulin, growth factors, amino acids, or energy status.
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Affiliation(s)
- Zhongfeng Wang
- Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
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Wade M, Wang YV, Wahl GM. The p53 orchestra: Mdm2 and Mdmx set the tone. Trends Cell Biol 2010; 20:299-309. [PMID: 20172729 DOI: 10.1016/j.tcb.2010.01.009] [Citation(s) in RCA: 342] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/22/2010] [Accepted: 01/28/2010] [Indexed: 11/25/2022]
Abstract
The activities of p53 cover diverse aspects of cell biology, including cell cycle control, apoptosis, metabolism, fertility, differentiation and cellular reprogramming. Although loss of p53 function engenders tumor susceptibility, hyperactivation of p53 is lethal. Therefore, p53 activity must be strictly regulated to maintain normal tissue homeostasis. Critical for the control of p53 function are its two main negative regulators: Mdm2 and Mdmx. Recent reports have provided insight into the complex mechanisms that regulate these two proteins and have revealed novel functions for each. Here, we review and evaluate models of Mdm2- and Mdmx-dependent regulation of p53 activity. Both Mdm2 and Mdmx receive input from numerous signaling pathways and interact with many proteins in addition to p53. Therefore, we also consider roles for Mdm2 and Mdmx in additional cancer-related networks, including Notch signaling and the epithelial-to-mesenchymal transition.
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Affiliation(s)
- Mark Wade
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Rayburn ER, Ezell SJ, Zhang R. Recent advances in validating MDM2 as a cancer target. Anticancer Agents Med Chem 2010; 9:882-903. [PMID: 19538162 DOI: 10.2174/187152009789124628] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 05/14/2008] [Indexed: 12/26/2022]
Abstract
The MDM2 oncogene is overexpressed in various human cancers. Its expression correlates with the phenotypes of high-grade, late-stage, and more resistant tumors. The auto-regulatory loop between MDM2 and the tumor suppressor p53 has long been considered the epitome of a rational target for cancer therapy. As such, many novel agents have been generated to interfere with the interaction of the two proteins, which results in the activation of p53. Among these agents are several small molecule inhibitors synthesized based upon the crystal structures of the MDM2-p53 complex. With use of high-throughput screening, several specific and effective agents for inhibition of the protein-protein interaction were discovered. Recent investigations, however, have demonstrated that many proteins regulate the MDM2-p53 interaction, and that MDM2 may have p53-independent oncogenic functions. In order for novel MDM2 inhibitors to be translated to the clinic, it is necessary to obtain a better understanding of the regulation of MDM2 and of the MDM2-p53 interaction. In particular, the implications of various interactions between certain regulator(s) and MDM2/p53 under different circumstances need to be elucidated to determine which pathway(s) represent the best targets for therapy. Targeting both MDM2 itself and regulators of MDM2 and the MDM2-p53 interaction, or use of MDM2 inhibitors in combination with conventional treatments, may improve prospects for tumor eradication.
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Affiliation(s)
- Elizabeth R Rayburn
- Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, University of Alabama at Birmingham, Birmingham, AL 35294-0019, USA
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Wip1, an oncogene targeting tumor suppressors expressed in intestinal stem cells. CURRENT COLORECTAL CANCER REPORTS 2009. [DOI: 10.1007/s11888-009-0027-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Akinci MAM, Turner H, Taveras M, Barash A, Wang Z, Reinach P, Wolosin JM. Molecular profiling of conjunctival epithelial side-population stem cells: atypical cell surface markers and sources of a slow-cycling phenotype. Invest Ophthalmol Vis Sci 2009; 50:4162-72. [PMID: 19324848 DOI: 10.1167/iovs.08-2861] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Side-population (SP) cells isolated from limbal and conjunctival epithelia derive from cells that are slow cycling in vivo, a known feature of tissue stem cells. The purpose of this study was to define the molecular signature of the conjunctival SP cells and identify markers and signaling pathways associated with the phenotype of these cells. METHODS Overnight cultures of freshly isolated human conjunctival epithelial cells stained with Hoechst 33342 were sorted by flow cytometry into SP and non-SP cohorts. Isolated RNA was processed for microarray analysis using a commercial oligonucleotide spotted array. Results were validated at the gene and protein levels by quantitative PCR and immunologic methods. Data mining methods were used to identify cellular processes relevant for stem cell function. RESULTS Comparative analyses of transcripts expression based on present and absent software calls across four replicate experiments identified 16,993 conjunctival epithelial transcripts including 10,266 unique known genes of approximately 24,000 represented in the array. Of those genes, 1254 and 363 were overexpressed (>2-fold) or underexpressed (<0.5-fold), respectively, in the SP. The overexpressed set included genes coding for proteins that have been associated with (1) embryonic development and/or stem cell self renewal (MSX, MEIS, ID, Hes1, and SIX homeodomain genes); (2) cell survival (e.g., CYP1A1 to degrade aromatic genotoxic compounds); (3) cycling rate (e.g., DUSPs and Pax6 to foster slow cycling); and (4) genes whose expression is not typical in epithelia (e.g., CD62E). CONCLUSIONS The molecular signature of conjunctival SP cells is consistent with a stem cell phenotype. Their gene expression patterns underpin slow cycling and plasticity, features associated with tissue stem cells. The results provide valuable insights for the preservation and/or expansion of epithelial stem cells.
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Affiliation(s)
- M A Murat Akinci
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York 10029-6574, USA
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Lee JT, Lehmann BD, Terrian DM, Chappell WH, Stivala F, Libra M, Martelli AM, Steelman LS, McCubrey JA. Targeting prostate cancer based on signal transduction and cell cycle pathways. Cell Cycle 2008; 7:1745-62. [PMID: 18594202 DOI: 10.4161/cc.7.12.6166] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prostate cancer remains a leading cause of death in men despite increased capacity to diagnose at earlier stages. After prostate cancer has become hormone independent, which often occurs after hormonal ablation therapies, it is difficult to effectively treat. Prostate cancer may arise from mutations and dysregulation of various genes involved in regulation signal transduction (e.g., PTEN, Akt, etc.,) and the cell cycle (e.g., p53, p21(Cip1), p27(Kip1), Rb, etc.,). This review focuses on the aberrant interactions of signal transduction and cell cycle genes products and how they can contribute to prostate cancer and alter therapeutic effectiveness.
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Affiliation(s)
- John T Lee
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, North Carolina 27858, USA
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