1
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Ehrenfeld M, Segeth F, Mantwill K, Brockhaus C, Zhao Y, Ploner C, Kolk A, Gschwend JE, Nawroth R, Holm PS. Targeting Cell Cycle Facilitates E1A-Independent Adenoviral Replication. J Virol 2023; 97:e0037023. [PMID: 37219458 PMCID: PMC10308897 DOI: 10.1128/jvi.00370-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/01/2023] [Indexed: 05/24/2023] Open
Abstract
DNA replication of E1-deleted first-generation adenoviruses (AdV) in cultured cancer cells has been reported repeatedly and it was suggested that certain cellular proteins could functionally compensate for E1A, leading to the expression of the early region 2 (E2)-encoded proteins and subsequently virus replication. Referring to this, the observation was named E1A-like activity. In this study, we investigated different cell cycle inhibitors with respect to their ability to increase viral DNA replication of dl70-3, an E1-deleted adenovirus. Our analyses of this issue revealed that in particular inhibition of cyclin-dependent kinases 4/6 (CDK4/6i) increased E1-independent adenovirus E2-expression and viral DNA replication. Detailed analysis of the E2-expression in dl70-3 infected cells by RT-qPCR showed that the increase in E2-expression originated from the E2-early promoter. Mutations of the two E2F-binding sites in the E2-early promoter (pE2early-LucM) caused a significant reduction in E2-early promoter activity in trans-activation assays. Accordingly, mutations of the E2F-binding sites in the E2-early promoter in a virus named dl70-3/E2Fm completely abolished CDK4/6i induced viral DNA replication. Thus, our data show that E2F-binding sites in the E2-early promoter are crucial for E1A independent adenoviral DNA replication of E1-deleted vectors in cancer cells. IMPORTANCE E1-deleted AdV vectors are considered replication deficient and are important tools for the study of virus biology, gene therapy, and large-scale vaccine development. However, deletion of the E1 genes does not completely abolish viral DNA replication in cancer cells. Here, we report, that the two E2F-binding sites in the adenoviral E2-early promoter contribute substantially to the so-called E1A-like activity in tumor cells. With this finding, on the one hand, the safety profile of viral vaccine vectors can be increased and, on the other hand, the oncolytic property for cancer therapy might be improved through targeted manipulation of the host cell.
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Affiliation(s)
- Maximilian Ehrenfeld
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Felicia Segeth
- Department of Oral and Maxillofacial Surgery, Medical University of Innsbruck, Innsbruck, Austria
- Department of Molecular Biology, Leopold-Franzens-Universität Innsbruck, Austria
| | - Klaus Mantwill
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Corinna Brockhaus
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Yuling Zhao
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Ploner
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Andreas Kolk
- Department of Oral and Maxillofacial Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Jürgen E. Gschwend
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Roman Nawroth
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Per Sonne Holm
- Department of Urology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Oral and Maxillofacial Surgery, Medical University of Innsbruck, Innsbruck, Austria
- XVir Therapeutics GmbH, Munich, Germany
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2
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Szwarc MM, Guarnieri AL, Joshi M, Duc HN, Laird MC, Pandey A, Khanal S, Dohm E, Bui AK, Sullivan KD, Galbraith MD, Andrysik Z, Espinosa JM. FAM193A is a positive regulator of p53 activity. Cell Rep 2023; 42:112230. [PMID: 36897777 PMCID: PMC10164416 DOI: 10.1016/j.celrep.2023.112230] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/21/2022] [Accepted: 02/21/2023] [Indexed: 03/11/2023] Open
Abstract
Inactivation of the p53 tumor suppressor, either by mutations or through hyperactivation of repressors such as MDM2 and MDM4, is a hallmark of cancer. Although many inhibitors of the p53-MDM2/4 interaction have been developed, such as Nutlin, their therapeutic value is limited by highly heterogeneous cellular responses. We report here a multi-omics investigation of the cellular response to MDM2/4 inhibitors, leading to identification of FAM193A as a widespread regulator of p53 function. CRISPR screening identified FAM193A as necessary for the response to Nutlin. FAM193A expression correlates with Nutlin sensitivity across hundreds of cell lines. Furthermore, genetic codependency data highlight FAM193A as a component of the p53 pathway across diverse tumor types. Mechanistically, FAM193A interacts with MDM4, and FAM193A depletion stabilizes MDM4 and inhibits the p53 transcriptional program. Last, FAM193A expression is associated with better prognosis in multiple malignancies. Altogether, these results identify FAM193A as a positive regulator of p53.
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Affiliation(s)
- Maria M Szwarc
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anna L Guarnieri
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Molishree Joshi
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Functional Genomics Facility, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Huy N Duc
- Functional Genomics Facility, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Madison C Laird
- Functional Genomics Facility, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ahwan Pandey
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Santosh Khanal
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Emily Dohm
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Aimee K Bui
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kelly D Sullivan
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Matthew D Galbraith
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zdenek Andrysik
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - Joaquin M Espinosa
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Functional Genomics Facility, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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3
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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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4
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Portman N, Chen J, Lim E. MDM2 as a Rational Target for Intervention in CDK4/6 Inhibitor Resistant, Hormone Receptor Positive Breast Cancer. Front Oncol 2021; 11:777867. [PMID: 34804982 PMCID: PMC8596371 DOI: 10.3389/fonc.2021.777867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
With the adoption of inhibitors of cyclin dependent kinases 4 and 6 (CDK4/6i) in combination with endocrine therapy as standard of care for the treatment of advanced and metastatic estrogen receptor positive (ER+) breast cancer, the search is now on for novel therapeutic options to manage the disease after the inevitable development of resistance to CDK4/6i. In this review we will consider the integral role that the p53/MDM2 axis plays in the interactions between CDK4/6, ERα, and inhibitors of these molecules, the current preclinical evidence for the efficacy of MDM2 inhibitors in ER+ breast cancer, and discuss the possibility of targeting the p53/MDM2 via inhibition of MDM2 in the CDK4/6i resistance setting.
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Affiliation(s)
- Neil Portman
- Cancer Theme, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales (UNSW) Sydney, Kensington, NSW, Australia
| | - Julia Chen
- Cancer Theme, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales (UNSW) Sydney, Kensington, NSW, Australia
| | - Elgene Lim
- Cancer Theme, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales (UNSW) Sydney, Kensington, NSW, Australia
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5
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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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6
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Uxa S, Bernhart SH, Mages CFS, Fischer M, Kohler R, Hoffmann S, Stadler PF, Engeland K, Müller GA. DREAM and RB cooperate to induce gene repression and cell-cycle arrest in response to p53 activation. Nucleic Acids Res 2019; 47:9087-9103. [PMID: 31400114 PMCID: PMC6753476 DOI: 10.1093/nar/gkz635] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/07/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
Most human cancers acquire mutations causing defects in the p53 signaling pathway. The tumor suppressor p53 becomes activated in response to genotoxic stress and is essential for arresting the cell cycle to facilitate DNA repair or to initiate apoptosis. p53-induced cell cycle-arrest is mediated by expression of the CDK inhibitor p21WAF1/Cip1, which prevents phosphorylation and inactivation of the pocket proteins RB, p130, and p107. In a hypophosphorylated state, pocket proteins bind to E2F factors forming RB-E2F and DREAM transcriptional repressor complexes. Here, we analyze the influence of RB and DREAM on p53-induced gene repression and cell-cycle arrest. We show that abrogation of DREAM function by knockout of the DREAM component LIN37 results in a reduced repression of cell-cycle genes. We identify the genes repressed by the p53-DREAM pathway and describe a set of genes that is downregulated by p53 independent of LIN37/DREAM. Most strikingly, p53-dependent repression of cell-cycle genes is completely abrogated in LIN37-/-;RB-/- cells leading to a loss of the G1/S checkpoint. Taken together, we show that DREAM and RB are key factors in the p53 signaling pathway to downregulate a large number of cell-cycle genes and to arrest the cell cycle at the G1/S transition.
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Affiliation(s)
- Sigrid Uxa
- Molecular Oncology, Department of Gynaecology, Medical School, Leipzig University, 04103 Leipzig, Germany
| | - Stephan H Bernhart
- Transcriptome Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107 Leipzig, Germany
| | - Christina F S Mages
- Molecular Oncology, Department of Gynaecology, Medical School, Leipzig University, 04103 Leipzig, Germany
| | - Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), 07745 Jena, Germany
| | - Robin Kohler
- Molecular Oncology, Department of Gynaecology, Medical School, Leipzig University, 04103 Leipzig, Germany
| | - Steve Hoffmann
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), 07745 Jena, Germany
| | - Peter F Stadler
- Transcriptome Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107 Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Leipzig Research Center for Civilization Diseases; and Competence Center for Scalable Data Services and Solutions Dresden/Leipzig, Leipzig University, 04107 Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, 04103 Leipzig, Germany.,Institute for Theoretical Chemistry, University of Vienna, A-1090 Wien, Austria.,Facultad de Ciencias, Universidad National de Colombia, Sede Bogota, Colombia.,Santa Fe Institute, Santa Fe, NM 87501, USA
| | - Kurt Engeland
- Molecular Oncology, Department of Gynaecology, Medical School, Leipzig University, 04103 Leipzig, Germany
| | - Gerd A Müller
- Molecular Oncology, Department of Gynaecology, Medical School, Leipzig University, 04103 Leipzig, Germany.,Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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7
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Bazanov DR, Pervushin NV, Savitskaya VY, Anikina LV, Proskurnina MV, Lozinskaya NA, Kopeina GS. 2,4,5-Tris(alkoxyaryl)imidazoline derivatives as potent scaffold for novel p53-MDM2 interaction inhibitors: Design, synthesis, and biological evaluation. Bioorg Med Chem Lett 2019; 29:2364-2368. [PMID: 31196710 DOI: 10.1016/j.bmcl.2019.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
Abstract
Imidazoline-based small molecule inhibitors of p53-MDM2 interaction intended for the treatment of p53 wild-type tumors are the promising structures for design of anticancer drugs. Based on fragment approach we have investigated a key role of substituents in cis-imidazoline core for biological activity of nutlin family compounds. Although the necessity of the substituents in the phenyl rings of cis-imidazoline has been shown, there are no studies in which the replacements of a halogen by other substituents have been investigated. A series of simple cis-imidazoline derivatives containing halogen, hydroxy and alkoxy-substituents were synthesized. The biological activity of the compounds was studied using assays of cytotoxicity (MTT) and p53 level. It was found that the hydroxyl-derivatives were not cytotoxic whereas the alkoxy analogues were the same or more active as halogen-substituted compounds in cell viability test. The synthesized alkoxy derivatives induced an increase of p53 level and did not promote necrotic cell death in the concentration up to 40 µM.
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Affiliation(s)
- Daniil R Bazanov
- Department of Chemistry, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119992 Moscow, Russian Federation
| | - Nikolay V Pervushin
- Department of Medicine, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119991 Moscow, Russian Federation
| | - Victoria Yu Savitskaya
- Department of Chemistry, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119992 Moscow, Russian Federation
| | - Lada V Anikina
- Institute of Physiologically Active Substances of RAS, 1, Northern Passage, 142432 Moscow Region, Russian Federation
| | - Marina V Proskurnina
- Department of Chemistry, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119992 Moscow, Russian Federation; Institute of Physiologically Active Substances of RAS, 1, Northern Passage, 142432 Moscow Region, Russian Federation
| | - Natalia A Lozinskaya
- Department of Chemistry, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119992 Moscow, Russian Federation; Institute of Physiologically Active Substances of RAS, 1, Northern Passage, 142432 Moscow Region, Russian Federation.
| | - Gelina S Kopeina
- Department of Medicine, M. V. Lomonosov Moscow State University, 1, Leninskie Gory, 119991 Moscow, Russian Federation.
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8
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CDK4 inhibition diminishes p53 activation by MDM2 antagonists. Cell Death Dis 2018; 9:918. [PMID: 30206211 PMCID: PMC6133967 DOI: 10.1038/s41419-018-0968-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 07/26/2018] [Indexed: 11/25/2022]
Abstract
The genes encoding MDM2 and CDK4 are frequently co-amplified in sarcomas, and inhibitors to both targets are approved or clinically tested for therapy. However, we show that inhibitors of MDM2 and CDK4 antagonize each other in their cytotoxicity towards sarcoma cells. CDK4 inhibition attenuates the induction of p53-responsive genes upon MDM2 inhibition. Moreover, the p53 response was also attenuated when co-depleting MDM2 and CDK4 with siRNA, compared to MDM2 single knockdown. The complexes of p53 and MDM2, as well as CDK4 and Cyclin D1, physically associated with each other, suggesting direct regulation of p53 by CDK4. Interestingly, CDK4 inhibition did not reduce p53 binding or histone acetylation at promoters, but rather attenuated the subsequent recruitment of RNA Polymerase II. Taken together, our results suggest that caution must be used when considering combined CDK4 and MDM2 inhibition for patient treatment. Moreover, they uncover a hitherto unknown role for CDK4 and Cyclin D1 in sustaining p53 activity.
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9
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Inhibition of MDM2 via Nutlin-3A: A Potential Therapeutic Approach for Pleural Mesotheliomas with MDM2-Induced Inactivation of Wild-Type P53. JOURNAL OF ONCOLOGY 2018; 2018:1986982. [PMID: 30112000 PMCID: PMC6077509 DOI: 10.1155/2018/1986982] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/23/2018] [Accepted: 06/11/2018] [Indexed: 12/12/2022]
Abstract
Previously, our group demonstrated that nuclear expression of E3 ubiquitin ligase (MDM2) in malignant pleural mesothelioma (MPM) is significantly associated with decreased overall survival. A possible explanation may be that overexpression of MDM2 leads to a proteasomal degradation of TP53 that eventually results in a loss of TP53-induced apoptosis and senescence. It is well known from other tumor entities that restoration of TP53 activity, e.g., by MDM2 inhibition, results in an instant TP53-induced stress and/or DNA damage response of cancer cells. Nutlin-3A (a cis-imidazoline analogue) has been described as a potent and selective MDM2 inhibitor preventing MDM2-TP53-interaction by specific binding to the hydrophobic TP53-binding pocket of MDM2. In the present study, the effects of MDM2 inhibition in MPM via Nutlin-3A and standard platinum based chemotherapeutic agents were comparatively tested in three MPM cell lines (NCI-H2052, MSTO-211H, and NCI-H2452) showing different expression profiles of TP53, MDM2, and its physiological inhibitor of MDM2—P14/ARF. Our in vitro experiments on MPM cell lines revealed that Nutlin-3A in combination with cisplatin resulted in up to 9.75 times higher induction of senescence (p=0.0050) and up to 5 times higher apoptosis rate (p=0.0067) compared to the commonly applied cisplatin and pemetrexed regimens. Thus Nutlin-3A, a potent inhibitor of MDM2, is associated with a significant induction of senescence and apoptosis in MPM cell lines, making Nutlin-3A a promising substance for a targeted therapy in the subgroup of MPM showing MDM2 overexpression.
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10
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Periyasamy M, Singh AK, Gemma C, Kranjec C, Farzan R, Leach DA, Navaratnam N, Pálinkás HL, Vértessy BG, Fenton TR, Doorbar J, Fuller-Pace F, Meek DW, Coombes RC, Buluwela L, Ali S. p53 controls expression of the DNA deaminase APOBEC3B to limit its potential mutagenic activity in cancer cells. Nucleic Acids Res 2017; 45:11056-11069. [PMID: 28977491 PMCID: PMC5737468 DOI: 10.1093/nar/gkx721] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/30/2017] [Accepted: 08/08/2017] [Indexed: 12/28/2022] Open
Abstract
Cancer genome sequencing has implicated the cytosine deaminase activity of apolipoprotein B mRNA editing enzyme catalytic polypeptide-like (APOBEC) genes as an important source of mutations in diverse cancers, with APOBEC3B (A3B) expression especially correlated with such cancer mutations. To better understand the processes directing A3B over-expression in cancer, and possible therapeutic avenues for targeting A3B, we have investigated the regulation of A3B gene expression. Here, we show that A3B expression is inversely related to p53 status in different cancer types and demonstrate that this is due to a direct and pivotal role for p53 in repressing A3B expression. This occurs through the induction of p21 (CDKN1A) and the recruitment of the repressive DREAM complex to the A3B gene promoter, such that loss of p53 through mutation, or human papilloma virus-mediated inhibition, prevents recruitment of the complex, thereby causing elevated A3B expression and cytosine deaminase activity in cancer cells. As p53 is frequently mutated in cancer, our findings provide a mechanism by which p53 loss can promote cancer mutagenesis.
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Affiliation(s)
- Manikandan Periyasamy
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Anup K. Singh
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Carolina Gemma
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Christian Kranjec
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Raed Farzan
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Damien A. Leach
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Naveenan Navaratnam
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Hajnalka L. Pálinkás
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest 1111, Hungary
- Laboratory of Genome Metabolism and Repair, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary
| | - Beata G. Vértessy
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest 1111, Hungary
- Laboratory of Genome Metabolism and Repair, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary
| | - Tim R. Fenton
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - John Doorbar
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Frances Fuller-Pace
- Division of Cancer Research, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - David W. Meek
- Division of Cancer Research, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - R. Charles Coombes
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Laki Buluwela
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Simak Ali
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
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11
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Kalmodia S, Parameswaran S, Ganapathy K, Yang W, Barrow CJ, Kanwar JR, Roy K, Vasudevan M, Kulkarni K, Elchuri SV, Krishnakumar S. Characterization and Molecular Mechanism of Peptide-Conjugated Gold Nanoparticle Inhibiting p53-HDM2 Interaction in Retinoblastoma. MOLECULAR THERAPY. NUCLEIC ACIDS 2017; 9:349-364. [PMID: 29246314 PMCID: PMC5684491 DOI: 10.1016/j.omtn.2017.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 01/12/2023]
Abstract
Inhibition of the interaction between p53 and HDM2 is an effective therapeutic strategy in cancers that harbor a wild-type p53 protein such as retinoblastoma (RB). Nanoparticle-based delivery of therapeutic molecules has been shown to be advantageous in localized delivery, including to the eye, by overcoming ocular barriers. In this study, we utilized biocompatible gold nanoparticles (GNPs) to deliver anti-HDM2 peptide to RB cells. Characterization studies suggested that GNP-HDM2 was stable in biologically relevant solvents and had optimal cellular internalization capability, the primary requirement of any therapeutic molecule. GNP-HDM2 treatment in RB cells in vitro suggested that they function by arresting RB cells at the G2M phase of the cell cycle and initiating apoptosis. Analysis of molecular changes in GNP-HDM2-treated cells by qRT-PCR and western blotting revealed that the p53 protein was upregulated; however, transactivation of its downstream targets was minimal, except for the PUMA-BCl2 and Bax axis. Global gene expression and in silico bioinformatic analysis of GNP-HDM2-treated cells suggested that upregulation of p53 might presumptively mediate apoptosis through the induction of p53-inducible miRNAs.
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Affiliation(s)
- Sushma Kalmodia
- Department of Nano Biotechnology, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai 600 006, India; Centre for Chemistry and Biotechnology, Deakin University, Geelong Campus, Waurn Ponds, VIC 3216, Australia
| | - Sowmya Parameswaran
- Radheshyam Kanoi Stem Cell Laboratory, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai 600 006, India
| | - Kalaivani Ganapathy
- Department of Nano Biotechnology, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai 600 006, India
| | - Wenrong Yang
- Centre for Chemistry and Biotechnology, Deakin University, Geelong Campus, Waurn Ponds, VIC 3216, Australia
| | - Colin J Barrow
- Centre for Chemistry and Biotechnology, Deakin University, Geelong Campus, Waurn Ponds, VIC 3216, Australia
| | - Jagat R Kanwar
- Nanomedicine -Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Centre for Molecular and Medicine Research (C-MMR), Deakin University, Geelong Campus, Waurn Ponds, VIC 3217, Australia
| | - Kislay Roy
- Nanomedicine -Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Centre for Molecular and Medicine Research (C-MMR), Deakin University, Geelong Campus, Waurn Ponds, VIC 3217, Australia
| | | | | | - Sailaja V Elchuri
- Department of Nano Biotechnology, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai 600 006, India
| | - Subramanian Krishnakumar
- Department of Nano Biotechnology, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai 600 006, India.
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12
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Laroche-Clary A, Chaire V, Algeo MP, Derieppe MA, Loarer FL, Italiano A. Combined targeting of MDM2 and CDK4 is synergistic in dedifferentiated liposarcomas. J Hematol Oncol 2017. [PMID: 28629371 PMCID: PMC5477309 DOI: 10.1186/s13045-017-0482-3] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Purpose MDM2 and CDK4 are frequently co-amplified in well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS). We aimed to determine whether combined MDM2/CDK4 targeting is associated with higher antitumour activity than a single agent in preclinical models of DDLPS. Experimental design DDLPS cells were exposed to RG7388 (MDM2 antagonist) and palbociclib (CDK4 inhibitor), and apoptosis and signalling/survival pathway perturbations were monitored by flow cytometry and Western blotting. Xenograft mouse models were used to assess tumour growth and survival. Treatment efficacy was assessed by Western blotting, histopathology and tumour volume. Results RG7388 and palbociclib together exerted a greater antitumour effect than either drug alone, with significant differences in cell viability after a 72-h treatment with RG7388 and/or palbociclib. The combination treatment significantly increased apoptosis compared to the single agents. We then analysed the in vivo antitumour activity of RG7388 and palbociclib in a xenograft model of DDLPS. The combination regimen reduced the tumour growth rate compared with a single agent alone and significantly increased the median progression-free survival. Conclusions Our results provide a strong rationale for evaluating the therapeutic potential of CDK4 inhibitors as potentiators of MDM2 antagonists in DDLPS and justify clinical trials in this setting.
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Affiliation(s)
- Audrey Laroche-Clary
- Université de Bordeaux, Bordeaux, France.,Institut National de la Santé et de la Recherche Medicale (INSERM) U1218, Institut Bergonié, 229 cours de l'Argonne, 33076, Bordeaux cedex, France
| | - Vanessa Chaire
- Université de Bordeaux, Bordeaux, France.,Institut National de la Santé et de la Recherche Medicale (INSERM) U1218, Institut Bergonié, 229 cours de l'Argonne, 33076, Bordeaux cedex, France
| | | | | | | | - Antoine Italiano
- Institut National de la Santé et de la Recherche Medicale (INSERM) U1218, Institut Bergonié, 229 cours de l'Argonne, 33076, Bordeaux cedex, France. .,Department of Medical Oncology, Institut Bergonié, Bordeaux, France.
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13
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Yuan S, Friedman DL, Daniels AB. Alternative Chemotherapeutic Agents for the Treatment of Retinoblastoma Using the Intra-Arterial and Intravitreal Routes: A Path Forward Toward Drug Discovery. Int Ophthalmol Clin 2017; 57:129-141. [PMID: 27898619 DOI: 10.1097/iio.0000000000000154] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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14
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Roles of pRB in the Regulation of Nucleosome and Chromatin Structures. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5959721. [PMID: 28101510 PMCID: PMC5215604 DOI: 10.1155/2016/5959721] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/08/2016] [Indexed: 01/31/2023]
Abstract
Retinoblastoma protein (pRB) interacts with E2F and other protein factors to play a pivotal role in regulating the expression of target genes that induce cell cycle arrest, apoptosis, and differentiation. pRB controls the local promoter activity and has the ability to change the structure of nucleosomes and/or chromosomes via histone modification, epigenetic changes, chromatin remodeling, and chromosome organization. Functional inactivation of pRB perturbs these cellular events and causes dysregulated cell growth and chromosome instability, which are hallmarks of cancer cells. The role of pRB in regulation of nucleosome/chromatin structures has been shown to link to tumor suppression. This review focuses on the ability of pRB to control nucleosome/chromatin structures via physical interactions with histone modifiers and chromatin factors and describes cancer therapies based on targeting these protein factors.
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15
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Merten L, Agaimy A, Moskalev EA, Giedl J, Kayser C, Geddert H, Schaefer IM, Cameron S, Werner M, Ströbel P, Hartmann A, Haller F. Inactivating Mutations of RB1 and TP53 Correlate With Sarcomatous Histomorphology and Metastasis/Recurrence in Gastrointestinal Stromal Tumors. Am J Clin Pathol 2016; 146:718-726. [PMID: 28028119 DOI: 10.1093/ajcp/aqw193] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVES Loss-of-function mutations in TP53 and CDKN2A have been found at varying frequencies in gastrointestinal stromal tumors (GISTs), while no mutations of RB1 have been reported to date. The aim of the current study was to determine the mutation frequency of TP53, RB1, and CDKN2A in GISTs. METHODS A cohort of 83 primary untreated GISTs was analyzed for mutations in TP53, RB1, and CDKN2A by massive parallel sequencing. Tumors with mutations in TP53 and RB1 were analyzed by fluorescence in situ hybridization for the corresponding gene loci. RESULTS Two GISTs harbored inactivating mutations in RB1, and two other GISTs displayed inactivating mutations in TP53 All four tumors were KIT mutant high-risk tumors with highly cellular sarcomatous histomorphology and variable combinations of plump spindle cells to epithelioid highly atypical cells and high mitotic activity. Three of these patients developed recurrent or metastatic disease, while the fourth patient showed tumor rupture intraoperatively. The combined overall frequency of TP53 and RB1 mutations was 13% considering high-risk or malignant GISTs. CONCLUSIONS TP53 and RB1 mutations seem to be restricted to high-risk/malignant GISTs and occur at an equal although relatively low frequency.
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Affiliation(s)
- Larissa Merten
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Abbas Agaimy
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Evgeny A Moskalev
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Johannes Giedl
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Claudia Kayser
- Institute of Pathology, Albert-Ludwigs University, Freiburg, Germany
| | - Helene Geddert
- Institute of Pathology, St. Vincentius Hospital, Karlsruhe, Germany
| | - Inga-Marie Schaefer
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; and
| | - Silke Cameron
- Clinic for Gastroenterology and Gastrointestinal Oncology
| | - Martin Werner
- Institute of Pathology, Albert-Ludwigs University, Freiburg, Germany
| | - Philip Ströbel
- Institute of Pathology, Georg August University, Göttingen, Germany
| | - Arndt Hartmann
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Florian Haller
- From the Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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16
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Chen J. The Cell-Cycle Arrest and Apoptotic Functions of p53 in Tumor Initiation and Progression. Cold Spring Harb Perspect Med 2016; 6:a026104. [PMID: 26931810 DOI: 10.1101/cshperspect.a026104] [Citation(s) in RCA: 644] [Impact Index Per Article: 80.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
P53 is a transcription factor highly inducible by many stress signals such as DNA damage, oncogene activation, and nutrient deprivation. Cell-cycle arrest and apoptosis are the most prominent outcomes of p53 activation. Many studies showed that p53 cell-cycle and apoptosis functions are important for preventing tumor development. p53 also regulates many cellular processes including metabolism, antioxidant response, and DNA repair. Emerging evidence suggests that these noncanonical p53 activities may also have potent antitumor effects within certain context. This review focuses on the cell-cycle arrest and apoptosis functions of p53, their roles in tumor suppression, and the regulation of cell fate decision after p53 activation.
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Affiliation(s)
- Jiandong Chen
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, Florida 33612
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17
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Walsh EM, Niu M, Bergholz J, Xiao ZXJ. Nutlin-3 down-regulates retinoblastoma protein expression and inhibits muscle cell differentiation. Biochem Biophys Res Commun 2015; 461:293-9. [PMID: 25871794 DOI: 10.1016/j.bbrc.2015.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/04/2015] [Indexed: 11/17/2022]
Abstract
The p53 tumor suppressor gene plays a critical role in regulation of proliferation, cell death and differentiation. The MDM2 oncoprotein is a major negative regulator for p53 by binding to and targeting p53 for proteasome-mediated degradation. The small molecule inhibitor, nutlin-3, disrupts MDM2-p53 interaction resulting in stabilization and activation of p53 protein. We have previously shown that nutlin-3 activates p53, leading to MDM2 accumulation as concomitant of reduced retinoblastoma (Rb) protein stability. It is well known that Rb is important in muscle development and myoblast differentiation and that rhabdomyosarcoma (RMS), or cancer of the skeletal muscle, typically harbors MDM2 amplification. In this study, we show that nutlin-3 inhibited myoblast proliferation and effectively prevented myoblast differentiation, as evidenced by lack of expression of muscle differentiation markers including myogenin and myosin heavy chain (MyHC), as well as a failure to form multinucleated myotubes, which were associated with dramatic increases in MDM2 expression and decrease in Rb protein levels. These results indicate that nutlin-3 can effectively inhibit muscle cell differentiation.
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Affiliation(s)
- Erica M Walsh
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - MengMeng Niu
- Center of Growth, Metabolism and Aging, College of Life Sciences, Sichuan University, Chengdu, 610014 China
| | - Johann Bergholz
- Center of Growth, Metabolism and Aging, College of Life Sciences, Sichuan University, Chengdu, 610014 China
| | - Zhi-Xiong Jim Xiao
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA; Center of Growth, Metabolism and Aging, College of Life Sciences, Sichuan University, Chengdu, 610014 China.
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18
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Constitutional Nephrin Deficiency in Conditionally Immortalized Human Podocytes Induced Epithelial-Mesenchymal Transition, Supported by β-Catenin/NF-kappa B Activation: A Consequence of Cell Junction Impairment? Int J Nephrol 2013; 2013:457490. [PMID: 24392227 PMCID: PMC3874297 DOI: 10.1155/2013/457490] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/11/2013] [Indexed: 01/08/2023] Open
Abstract
The kidney glomerular podocytes are the cellular target of many chronic nephropathies both determined and acquired genetically. Mutations that affected the expression and/or the function of nephrin, a key component of the slit-diaphragm, are often causes of these pathologies. Recent findings showed that murine podocytes could undergo epithelial-mesenchymal transformation (EMT), suggesting new hypotheses about the pathogenesis of glomerular fibrosis. Here, we show that also human podocytes can undergo EMT, but more importantly nephrin ablation itself can trigger this phenotypic transformation. In fact, a model of human podocyte with engineered nephrin deficiency constitutionally expressed high levels of α-SMA, vimentin, fibronectin, and other hallmarks of EMT. Since it is known that cell contact abrogation is one of the triggers of EMT, we reasoned that nephrin loss could account for such cell junction disruption and cause the EMT. Therefore, we demonstrated that also normal podocytes could spontaneously undergo EMT if grown in Ca2+-free medium, which is known to impair cell contacts. The analysis of the main intracellular signal transduction pathways evidenced some major anomalies consequent with the nephrin abrogation. The most intriguing was the activation of β-catenin pathway, which plays a critical role in podocyte ontogenesis as well as in the nephrin expression and EMT regulation. Also other important signaling proteins, like NF-κB, p53, and retinoblastoma protein (RB), showed important activity modifications. Interestingly, most of the above indicated signaling pathway alterations were again reproducible by cell junction rupture, induced by Ca2+ deprivation. Finally, immunofluorescence analysis on kidney sections of patients with NS of Finnish type confirmed the constitutive expression of α-SMA.
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19
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Du W, Yi Y, Zhang H, Bergholz J, Wu J, Ying H, Zhang Y, Xiao ZXJ. Rapamycin inhibits IGF-1-mediated up-regulation of MDM2 and sensitizes cancer cells to chemotherapy. PLoS One 2013; 8:e63179. [PMID: 23638184 PMCID: PMC3640086 DOI: 10.1371/journal.pone.0063179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 03/29/2013] [Indexed: 11/19/2022] Open
Abstract
The Murine Double Minute 2 (MDM2) protein is a key regulator of cell proliferation and apoptosis that acts primarily by inhibiting the p53 tumor suppressor. Similarly, the PI3-Kinase (PI3K)/AKT pathway is critical for growth factor-mediated cell survival. Additionally, it has been reported that AKT can directly phosphorylate and activate MDM2. In this study, we show that IGF-1 up-regulates MDM2 protein levels in a PI3K/AKT-dependent manner. Inhibition of mTOR by rapamycin or expression of a dominant negative eukaryotic initiation factor 4E binding protein 1 (4EBP1) mutant protein, as well as ablation of eukaryotic initiation factor 4E (eIF4E), efficiently abolishes IGF-1-mediated up-regulation of MDM2. In addition, we show that rapamycin effectively inhibits MDM2 expression and sensitizes cancer cells to chemotherapy. Taken together, this study reveals a novel mechanism by which IGF-1 activates MDM2 via the mTOR pathway, and that pharmacologic inhibition of mTOR combined with chemotherapy may be more effective in treatment of a subset of cancers harboring increased MDM2 activation.
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Affiliation(s)
- Wei Du
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Yong Yi
- Center of Growth, Metabolism and Aging, College of Life Sciences and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Haibo Zhang
- Center of Growth, Metabolism and Aging, College of Life Sciences and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Johann Bergholz
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Center of Growth, Metabolism and Aging, College of Life Sciences and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Junfeng Wu
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Haoqiang Ying
- The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Yujun Zhang
- Center of Growth, Metabolism and Aging, College of Life Sciences and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Zhi-Xiong Jim Xiao
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Center of Growth, Metabolism and Aging, College of Life Sciences and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
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20
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Live-cell imaging of p53 interactions using a novel Venus-based bimolecular fluorescence complementation system. Biochem Pharmacol 2012; 85:745-52. [PMID: 23261524 DOI: 10.1016/j.bcp.2012.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 11/28/2012] [Accepted: 12/12/2012] [Indexed: 12/14/2022]
Abstract
p53 plays an important role in regulating a wide variety of cellular processes, such as cell cycle arrest and/or apoptosis. Dysfunction of p53 is frequently associated with several pathologies, such as cancer and neurodegenerative diseases. In recent years substantial progress has been made in developing novel p53-activating molecules. Importantly, modulation of p53 interaction with its main inhibitor, Mdm2, has been highlighted as a promising therapeutic target. In this regard, bimolecular fluorescence complementation (BiFC) analysis, by providing direct visualization of protein interactions in living cells, offers a straightforward method to identify potential modulators of protein interactions. In this study, we developed a simple and robust Venus-based BiFC system to screen for modulators of p53-p53 and p53-Mdm2 interactions in live mammalian cells. We used nutlin-3, a well-known disruptor of p53-Mdm2 interaction, to validate the specificity of the assay. The reduction of BiFC signal mediated by nutlin-3 was correlated with an increase in Puma transactivation, PARP cleavage, and cell death. Finally, this novel BiFC approach was exploited to identify potential modulators of p53-Mdm2 complex formation among a commercially available chemical library of 33 protein phosphatase inhibitors. Our results constitute "proof-of-concept" that this model has strong potential as an alternative to traditional target-based drug discovery strategies. Identification of new modulators of p53-p53 and p53-Mdm2 interactions will be useful to achieve synergistic drug efficacy with currently used anti-tumor therapies.
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21
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Tang YA, Lin RK, Tsai YT, Hsu HS, Yang YC, Chen CY, Wang YC. MDM2 Overexpression Deregulates the Transcriptional Control of RB/E2F Leading to DNA Methyltransferase 3A Overexpression in Lung Cancer. Clin Cancer Res 2012; 18:4325-33. [DOI: 10.1158/1078-0432.ccr-11-2617] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Lenos K, de Lange J, Teunisse AFAS, Lodder K, Verlaan-de Vries M, Wiercinska E, van der Burg MJM, Szuhai K, Jochemsen AG. Oncogenic functions of hMDMX in in vitro transformation of primary human fibroblasts and embryonic retinoblasts. Mol Cancer 2011; 10:111. [PMID: 21910853 PMCID: PMC3179748 DOI: 10.1186/1476-4598-10-111] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 09/12/2011] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In around 50% of all human cancers the tumor suppressor p53 is mutated. It is generally assumed that in the remaining tumors the wild-type p53 protein is functionally impaired. The two main inhibitors of p53, hMDM2 (MDM2) and hMDMX (MDMX/MDM4) are frequently overexpressed in wild-type p53 tumors. Whereas the main activity of hMDM2 is to degrade p53 protein, its close homolog hMDMX does not degrade p53, but it represses its transcriptional activity. Here we study the role of hMDMX in the neoplastic transformation of human fibroblasts and embryonic retinoblasts, since a high number of retinoblastomas contain elevated hMDMX levels. METHODS We made use of an in vitro transformation model using a retroviral system of RNA interference and gene overexpression in primary human fibroblasts and embryonic retinoblasts. Consecutive knockdown of RB and p53, overexpression of SV40-small t, oncogenic HRasV12 and HA-hMDMX resulted in a number of stable cell lines representing different stages of the transformation process, enabling a comparison between loss of p53 and hMDMX overexpression. The cell lines were tested in various assays to assess their oncogenic potential. RESULTS Both p53-knockdown and hMDMX overexpression accelerated proliferation and prevented growth suppression induced by introduction of oncogenic Ras, which was required for anchorage-independent growth and the ability to form tumors in vivo. Furthermore, we found that hMDMX overexpression represses basal p53 activity to some extent. Transformed fibroblasts with very high levels of hMDMX became largely resistant to the p53 reactivating drug Nutlin-3. The Nutlin-3 response of hMDMX transformed retinoblasts was intact and resembled that of retinoblastoma cell lines. CONCLUSIONS Our studies show that hMDMX has the essential properties of an oncogene. Its constitutive expression contributes to the oncogenic phenotype of transformed human cells. Its main function appears to be p53 inactivation. Therefore, developing new drugs targeting hMDMX is a valid approach to obtain new treatments for a subset of human tumors expressing wild-type p53.
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Affiliation(s)
- Kristiaan Lenos
- Department of Molecular Cell Biology, Leiden University Medical Center, P,O, Box 9600, 2300 RC Leiden, The Netherlands
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C1 Domain-targeted isophthalate derivatives induce cell elongation and cell cycle arrest in HeLa cells. PLoS One 2011; 6:e20053. [PMID: 21629792 PMCID: PMC3100349 DOI: 10.1371/journal.pone.0020053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/11/2011] [Indexed: 11/19/2022] Open
Abstract
Diacylglycerol (DAG)-mediated signaling pathways, such as those mediated by protein kinase C (PKC), are central in regulating cell proliferation and apoptosis. DAG-responsive C1 domains are therefore considered attractive drug targets. Our group has designed a novel class of compounds targeted to the DAG binding site within the C1 domain of PKC. We have previously shown that these 5-(hydroxymethyl)isophthalates modulate PKC activation in living cells. In this study we investigated their effects on HeLa human cervical cancer cell viability and proliferation by using standard cytotoxicity tests and an automated imaging platform with machine vision technology. Cellular effects and their mechanisms were further characterized with the most potent compound, HMI-1a3. Isophthalate derivatives with high affinity to the PKC C1 domain exhibited antiproliferative and non-necrotic cytotoxic effects on HeLa cells. The anti-proliferative effect was irreversible and accompanied by cell elongation. HMI-1a3 induced down-regulation of retinoblastoma protein and cyclins A, B1, D1, and E. Effects of isophthalates on cell morphology, cell proliferation and expression of cell cycle-related proteins were different from those induced by phorbol 12-myristate-13-acetate (PMA) or bryostatin 1, but correlated closely to binding affinities. Therefore, the results strongly indicate that the effect is C1 domain-mediated.
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Multiple distinct molecular mechanisms influence sensitivity and resistance to MDM2 inhibitors in adult acute myelogenous leukemia. Blood 2010; 116:71-80. [PMID: 20404136 DOI: 10.1182/blood-2010-01-261628] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The survival of most patients with acute myelogenous leukemia (AML) remains poor, and novel therapeutic approaches are needed to improve outcomes. Given that the fraction of AML with mutated p53 is small ( approximately 10%), it appears rational to study MDM2 inhibitors as therapy for AML. Here, we report results of a detailed characterization of sensitivity and resistance to treatment ex vivo with the MDM2 inhibitor MI219 in AML blasts from 109 patients. In line with previous observations, all AML cases with mutated p53 were resistant to MI219. Importantly, approximately 30% of AML cases with unmutated p53 also demonstrated primary resistance to MI219. Analysis of potential mechanisms associated with MI219 resistance in AML blasts with wild-type p53 uncovered distinct molecular defects, including low or absent p53 protein induction after MDM2 inhibitor treatment or external irradiation. Furthermore, a separate subset of resistant blasts displayed robust p53 protein induction after MI219 treatment, indicative of defective p53 protein function or defects in the apoptotic p53 network. Finally, analysis of very sensitive AML cases uncovered a strong and significant association with mutated Flt3 status (Flt3-ITD), which for the first time identified a clinically high-risk group of AML that may particularly benefit from MDM2 inhibitor treatment.
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