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Yin Q, Hu Y, Dong Z, Lu J, Wang H. Cellular, Structural Basis, and Recent Progress for Targeting Murine Double Minute X (MDMX) in Tumors. J Med Chem 2024; 67:14723-14741. [PMID: 39185935 DOI: 10.1021/acs.jmedchem.4c00913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Murine double minute X (MDMX) is an oncoprotein that mainly has a negative regulatory effect on the tumor suppressor p53 to induce tumorigenesis. As MDMX is highly expressed in various types of tumor cells, targeting and inhibiting MDMX are becoming a promising strategy for treating cancers. However, the high degree of structural homology between MDMX and its homologous protein murine double minute 2 (MDM2) is a great challenge for the development of MDMX-targeted therapies. This review introduces the structure, distribution, and regulation of the MDMX, summarizes the structural features and structure-activity relationships (SARs) of MDMX ligands, and focuses on the differences between MDMX and MDM2 in these aspects. Our purpose of this work is to propose potential strategies to achieve the specific targeting of MDMX.
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Affiliation(s)
- Qikun Yin
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China
| | - Yuemiao Hu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China
| | - Zhiwen Dong
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China
| | - Jing Lu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China
| | - Hongbo Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China
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2
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Ni Y, Chen H, Cheng X, Sun B, Wu Z, Zhan Q, Zhuang Z. Hdm2 disrupts HdmX-mediated nuclear export of p53 by sequestering it in nucleus. Exp Cell Res 2024; 441:114185. [PMID: 39069150 DOI: 10.1016/j.yexcr.2024.114185] [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: 05/07/2024] [Revised: 07/24/2024] [Accepted: 07/25/2024] [Indexed: 07/30/2024]
Abstract
Dysfunction of the tumor suppressor p53 occurs in most human cancers, Hdm2 and HdmX play critical roles in p53 inactivation and degradation. Under unstressed conditions, HdmX binds to p53 like Hdm2, but HdmX cannot directly induce p53 degradation. Moreover, HdmX has been reported to stimulate Hdm2-mediated ubiquitination and degradation of p53. Here we reported that HdmX promoted the nuclear export of p53 independent of Hdm2 in living cells using FRET technology. Whereas, Hdm2 impeded HdmX-mediated nuclear export of p53 by sequestering it in nucleus. Interestingly, the C-terminal RING domain mutant Hdm2C464A formed heterooligomers with p53 in nucleus, which was inhibited by HdmX. The heterooligomers were located near PML-NBs. This study indicate that the nuclear Hdm2-HdmX interaction aborts the HdmX-mediated nuclear export of p53.
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Affiliation(s)
- Yue Ni
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China; Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510631, China
| | - Hongce Chen
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China.
| | - Xuecheng Cheng
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China
| | - Beini Sun
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China
| | - Zhirui Wu
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China
| | - Qiuqiang Zhan
- Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510631, China
| | - Zhengfei Zhuang
- MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, School of Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510631, China.
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3
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Lin W, Yan Y, Huang Q, Zheng D. MDMX in Cancer: A Partner of p53 and a p53-Independent Effector. Biologics 2024; 18:61-78. [PMID: 38318098 PMCID: PMC10839028 DOI: 10.2147/btt.s436629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/08/2023] [Indexed: 02/07/2024]
Abstract
The p53 tumor suppressor protein plays an important role in physiological and pathological processes. MDM2 and its homolog MDMX are the most important negative regulators of p53. Many studies have shown that MDMX promotes the growth of cancer cells by influencing the regulation of the downstream target gene of tumor suppressor p53. Studies have found that inhibiting the MDMX-p53 interaction can effectively restore the tumor suppressor activity of p53. MDMX has growth-promoting activities without p53 or in the presence of mutant p53. Therefore, it is extremely important to study the function of MDMX in tumorigenesis, progression and prognosis. This article mainly reviews the current research progress and mechanism on MDMX function, summarizes known MDMX inhibitors and provides new ideas for the development of more specific and effective MDMX inhibitors for cancer treatment.
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Affiliation(s)
- Wu Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, People’s Republic of China
| | - Yuxiang Yan
- Fujian Key Laboratory of Oral Diseases, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, People’s Republic of China
| | - Qingling Huang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, People’s Republic of China
| | - Dali Zheng
- Fujian Key Laboratory of Oral Diseases, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, People’s Republic of China
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4
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Zhou Y, Nakajima R, Shirasawa M, Fikriyanti M, Zhao L, Iwanaga R, Bradford AP, Kurayoshi K, Araki K, Ohtani K. Expanding Roles of the E2F-RB-p53 Pathway in Tumor Suppression. BIOLOGY 2023; 12:1511. [PMID: 38132337 PMCID: PMC10740672 DOI: 10.3390/biology12121511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
The transcription factor E2F links the RB pathway to the p53 pathway upon loss of function of pRB, thereby playing a pivotal role in the suppression of tumorigenesis. E2F fulfills a major role in cell proliferation by controlling a variety of growth-associated genes. The activity of E2F is controlled by the tumor suppressor pRB, which binds to E2F and actively suppresses target gene expression, thereby restraining cell proliferation. Signaling pathways originating from growth stimulative and growth suppressive signals converge on pRB (the RB pathway) to regulate E2F activity. In most cancers, the function of pRB is compromised by oncogenic mutations, and E2F activity is enhanced, thereby facilitating cell proliferation to promote tumorigenesis. Upon such events, E2F activates the Arf tumor suppressor gene, leading to activation of the tumor suppressor p53 to protect cells from tumorigenesis. ARF inactivates MDM2, which facilitates degradation of p53 through proteasome by ubiquitination (the p53 pathway). P53 suppresses tumorigenesis by inducing cellular senescence or apoptosis. Hence, in almost all cancers, the p53 pathway is also disabled. Here we will introduce the canonical functions of the RB-E2F-p53 pathway first and then the non-classical functions of each component, which may be relevant to cancer biology.
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Affiliation(s)
- Yaxuan Zhou
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Rinka Nakajima
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Mashiro Shirasawa
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Mariana Fikriyanti
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Lin Zhao
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
| | - Ritsuko Iwanaga
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Andrew P. Bradford
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Kenta Kurayoshi
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan;
| | - Keigo Araki
- Department of Morphological Biology, Ohu University School of Dentistry, 31-1 Misumido Tomitamachi, Koriyama, Fukushima 963-8611, Japan;
| | - Kiyoshi Ohtani
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan; (Y.Z.); (R.N.); (M.S.); (M.F.); (L.Z.)
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Mitobe Y, Suzuki S, Nakagawa-Saito Y, Togashi K, Sugai A, Sonoda Y, Kitanaka C, Okada M. Antagonizing MDM2 Overexpression Induced by MDM4 Inhibitor CEP-1347 Effectively Reactivates Wild-Type p53 in Malignant Brain Tumor Cells. Cancers (Basel) 2023; 15:4326. [PMID: 37686602 PMCID: PMC10486490 DOI: 10.3390/cancers15174326] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/14/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
The development of MDM4 inhibitors as an approach to reactivating p53 in human cancer is attracting increasing attention; however, whether they affect the function of MDM2 and how they interact with MDM2 inhibitors remain unknown. We addressed this question in the present study using CEP-1347, an inhibitor of MDM4 protein expression. The effects of CEP-1347, the genetic and/or pharmacological inhibition of MDM2, and their combination on the p53 pathway in malignant brain tumor cell lines expressing wild-type p53 were investigated by RT-PCR and Western blot analyses. The growth inhibitory effects of CEP-1347 alone or in combination with MDM2 on inhibition were examined by dye exclusion and/or colony formation assays. The treatment of malignant brain tumor cell lines with CEP-1347 markedly increased MDM2 protein expression, while blocking CEP-1347-induced MDM2 overexpression by genetic knockdown augmented the effects of CEP-1347 on the p53 pathway and cell growth. Blocking the MDM2-p53 interaction using the small molecule MDM2 inhibitor RG7112, but not MDM2 knockdown, reduced MDM4 expression. Consequently, RG7112 effectively cooperated with CEP-1347 to reduce MDM4 expression, activate the p53 pathway, and inhibit cell growth. The present results suggest the combination of CEP-1347-induced MDM2 overexpression with the selective inhibition of MDM2's interaction with p53, while preserving its ability to inhibit MDM4 expression, as a novel and rational strategy to effectively reactivate p53 in wild-type p53 cancer cells.
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Affiliation(s)
- Yuta Mitobe
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
- Department of Neurosurgery, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Shuhei Suzuki
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
- Department of Clinical Oncology, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Yurika Nakagawa-Saito
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Keita Togashi
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
- Department of Ophthalmology and Visual Sciences, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Asuka Sugai
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Yukihiko Sonoda
- Department of Neurosurgery, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Chifumi Kitanaka
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
- Research Institute for Promotion of Medical Sciences, Faculty of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Masashi Okada
- Department of Molecular Cancer Science, School of Medicine, Yamagata University, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
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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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Traweek RS, Cope BM, Roland CL, Keung EZ, Nassif EF, Erstad DJ. Targeting the MDM2-p53 pathway in dedifferentiated liposarcoma. Front Oncol 2022; 12:1006959. [PMID: 36439412 PMCID: PMC9684653 DOI: 10.3389/fonc.2022.1006959] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/19/2022] [Indexed: 10/12/2023] Open
Abstract
Dedifferentiated liposarcoma (DDLPS) is an aggressive adipogenic cancer with poor prognosis. DDLPS tumors are only modestly sensitive to chemotherapy and radiation, and there is a need for more effective therapies. Genetically, DDLPS is characterized by a low tumor mutational burden and frequent chromosomal structural abnormalities including amplification of the 12q13-15 chromosomal region and the MDM2 gene, which are defining features of DDLPS. The MDM2 protein is an E3 ubiquitin ligase that targets the tumor suppressor, p53, for proteasomal degradation. MDM2 amplification or overexpression in human malignancies is associated with cell-cycle progression and worse prognosis. The MDM2-p53 interaction has thus garnered interest as a therapeutic target for DDLPS and other malignancies. MDM2 binds p53 via a hydrophobic protein interaction that is easily accessible with synthetic analogues. Multiple agents have been developed, including Nutlins such as RG7112 and small molecular inhibitors including SAR405838 and HDM201. Preclinical in vitro and animal models have shown promising results with MDM2 inhibition, resulting in robust p53 reactivation and cancer cell death. However, multiple early-phase clinical trials have failed to show a benefit with MDM2 pathway inhibition for DDLPS. Mechanisms of resistance are being elucidated, and novel inhibitors and combination therapies are currently under investigation. This review provides an overview of these strategies for targeting MDM2 in DDLPS.
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Affiliation(s)
- Raymond S. Traweek
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Brandon M. Cope
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Christina L. Roland
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Emily Z. Keung
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Elise F. Nassif
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Derek J. Erstad
- Division of Surgical Oncology, Baylor College of Medicine, Houston, TX, United States
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Nagpal I, Yuan ZM. p53-mediated metabolic response to low doses of ionizing radiation. Int J Radiat Biol 2022; 99:934-940. [DOI: 10.1080/09553002.2022.2142983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Isha Nagpal
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Zhi-Min Yuan
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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9
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Lama R, Galster SL, Xu C, Davison LW, Chemler SR, Wang X. Dual Targeting of MDM4 and FTH1 by MMRi71 for Induced Protein Degradation and p53-Independent Apoptosis in Leukemia Cells. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27227665. [PMID: 36431769 PMCID: PMC9695299 DOI: 10.3390/molecules27227665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
MDM2 and MDM4 are cancer drug targets validated in multiple models for p53-based cancer therapies. The RING domains of MDM2 and non-p53-binder MDM2 splice isoforms form RING domain heterodimer polyubiquitin E3 ligases with MDM4, which regulate p53 stability in vivo and promote tumorigenesis independent of p53. Despite the importance of the MDM2 RING domain in p53 regulation and cancer development, small molecule inhibitors targeting the E3 ligase activity of MDM2-MDM4 are poorly explored. Here, we describe the synthesis and characterization of quinolinol derivatives for the identification of analogs that are capable of targeting the MDM2-MDM4 heterodimer E3 ligase and inducing apoptosis in cells. The structure-activity-relationship (SAR) study identified structural moieties critical for the inhibitory effects toward MDM2-MDM4 E3 ligase, the targeted degradation of MDM4 and FTH1 in cells, and anti-proliferation activity. Lead optimization led to the development of compound MMRi71 with improved activity. In addition to accumulating p53 proteins in wt-p53 bearing cancer cells as expected of any MDM2 inhibitors, MMRi71 effectively kills p53-null leukemia cells, an activity that conventional MDM2-p53 disrupting inhibitors lack. This study provides a prototype structure for developing MDM4/FTH1 dual-targeting inhibitors as potential cancer therapeutics.
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Affiliation(s)
- Rati Lama
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Samuel L. Galster
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Chao Xu
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Luke W. Davison
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Sherry R. Chemler
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
- Correspondence: (S.R.C.); (X.W.)
| | - Xinjiang Wang
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Correspondence: (S.R.C.); (X.W.)
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10
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Chen Q, Yang M, Liu X, Zhang J, Mi S, Wang Y, Xiao W, Yu Y. Blood transcriptome analysis and identification of genes associated with supernumerary teats in Chinese Holstein cows. J Dairy Sci 2022; 105:9837-9852. [DOI: 10.3168/jds.2022-22346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/20/2022] [Indexed: 11/17/2022]
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11
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Chinnam M, Xu C, Lama R, Zhang X, Cedeno CD, Wang Y, Stablewski AB, Goodrich DW, Wang X. MDM2 E3 ligase activity is essential for p53 regulation and cell cycle integrity. PLoS Genet 2022; 18:e1010171. [PMID: 35588102 PMCID: PMC9119546 DOI: 10.1371/journal.pgen.1010171] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/27/2022] [Indexed: 12/12/2022] Open
Abstract
MDM2 and MDM4 are key regulators of p53 and function as oncogenes when aberrantly expressed. MDM2 and MDM4 partner to suppress p53 transcriptional transactivation and polyubiquitinate p53 for degradation. The importance of MDM2 E3-ligase-mediated p53 regulation remains controversial. To resolve this, we generated mice with an Mdm2 L466A mutation that specifically compromises E2 interaction, abolishing MDM2 E3 ligase activity while preserving its ability to bind MDM4 and suppress p53 transactivation. Mdm2L466A/L466A mice exhibit p53-dependent embryonic lethality, demonstrating MDM2 E3 ligase activity is essential for p53 regulation in vivo. Unexpectedly, cells expressing Mdm2L466A manifest cell cycle G2-M transition defects and increased aneuploidy even in the absence of p53, suggesting MDM2 E3 ligase plays a p53-independent role in cell cycle regulation and genome integrity. Furthermore, cells bearing the E3-dead MDM2 mutant show aberrant cell cycle regulation in response to DNA damage. This study uncovers an uncharacterized role for MDM2’s E3 ligase activity in cell cycle beyond its essential role in regulating p53’s stability in vivo. The most frequently mutated protein in human cancer, the p53 tumor suppressor protein, is negatively regulated by the potentially oncogenic proteins MDM2 and MDM4. MDM2/MDM4 regulates p53 through two mechanisms, MDM2 E3 ubiquitin ligase activity marks p53 for degradation while MDM2/MDM4 can bind p53 to inhibit its ability to promote RNA transcription. Whether these mechanisms contribute to normal p53 regulation in vivo remains controversial. Using a newly developed mouse model that genetically separates these two mechanisms, we find that mice expressing MDM2 deficient specifically for E3 ubiquitin ligase activity do not survive embryonic development because unregulated p53 is lethal. In contrast to prior reports, MDM2 E3 ubiquitin ligase activity is thus required for p53 regulation during embryonic development. In addition, cells lacking MDM2 E3 ubiquitin ligase activity have cell cycle defects regardless of p53 status, uncovering a p53-independent function for MDM2 in regulating the cell cycle. Activating p53 by blocking physical interaction with MDM2/MDM4 is one currently pursued approach for cancer therapy, but this approach does not account for cancer-promoting activities of MDM2/MDM4 independent of p53. Findings reported here suggest targeting MDM2 E3 ligase activity directly may be advantageous as it would inhibit both p53-dependent and p53-independent oncogenic mechanisms.
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Affiliation(s)
- Meenalakshmi Chinnam
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
| | - Chao Xu
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
| | - Rati Lama
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
| | - Xiaojing Zhang
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
| | - Carlos D. Cedeno
- Flow and Image Cytometry Shared Resource, Buffalo, New York, United States of America
| | - Yanqing Wang
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
| | - Aimee B. Stablewski
- Department of Molecular & Cellular Biology, Buffalo, New York, United States of America
- Gene Targeting and Transgenic Shared Resource, Roswell Park Comprehensive Cancer Center, Buffalo, New York, United States of America
| | - David W. Goodrich
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
- * E-mail: (XW); (DWG)
| | - Xinjiang Wang
- Department of Pharmacology and Therapeutics, Buffalo, New York, United States of America
- * E-mail: (XW); (DWG)
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12
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Zhou R, Li Y, Wang N, Niu C, Huang X, Cao S, Huo X. MDM4 polymorphisms associated with the risk but not the prognosis of esophageal cancer in Cixian high-incidence region from northern China. Asia Pac J Clin Oncol 2022; 18:e435-e441. [PMID: 35098683 DOI: 10.1111/ajco.13746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 12/04/2021] [Indexed: 11/27/2022]
Abstract
AIM The mouse double minute 4 (MDM4) may contribute to tumorgenesis by inhibiting p53 tumor suppressor activity. This study was designed to investigate whether MDM4 polymorphisms could affect susceptibility to esophageal squamous cell carcinoma (ESCC) and the survival of ESCC patients in a population from Cixian high-incidence region of northern China, which has not been explored. METHODS MDM4 rs1380576 and rs4245739 were genotyped by polymerase chain reaction-ligase detection reaction (PCR-LDR) in 568 ESCC patients and 578 controls. RESULTS Compared to rs1380576 C/C genotype, C/G genotype was associated with decreased risk of ESCC (odds ratio [OR] = 0.761, 95% confidence interval [CI] = 0.595-0.973). Compared to rs4245739 A/A genotype, A/C or C/C genotype was related to increased susceptibility to ESCC (OR = 1.551, 95% CI = 1.001-2.402). Individuals with GC haplotype had significantly higher risk of ESCC than those with CA or GA haplotype (OR = 1.598, 95% CI = 1.048-2.438). Neither rs1380576 nor rs4245739 influenced the survival of ESCC patients. CONCLUSION rs1380576 and rs4245739 may be used to predict susceptibility to ESCC for population in Cixian high-incidence region.
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Affiliation(s)
- Rongmiao Zhou
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yan Li
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Na Wang
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Chaoxu Niu
- Department of Surgery, Shijiazhuang Ping'an Hospital, Shijiazhuang, China
| | - Xi Huang
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Shiru Cao
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiangran Huo
- Hebei Provincial Cancer Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
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13
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Kung CP, Weber JD. It’s Getting Complicated—A Fresh Look at p53-MDM2-ARF Triangle in Tumorigenesis and Cancer Therapy. Front Cell Dev Biol 2022; 10:818744. [PMID: 35155432 PMCID: PMC8833255 DOI: 10.3389/fcell.2022.818744] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/07/2022] [Indexed: 01/31/2023] Open
Abstract
Anti-tumorigenic mechanisms mediated by the tumor suppressor p53, upon oncogenic stresses, are our bodies’ greatest weapons to battle against cancer onset and development. Consequently, factors that possess significant p53-regulating activities have been subjects of serious interest from the cancer research community. Among them, MDM2 and ARF are considered the most influential p53 regulators due to their abilities to inhibit and activate p53 functions, respectively. MDM2 inhibits p53 by promoting ubiquitination and proteasome-mediated degradation of p53, while ARF activates p53 by physically interacting with MDM2 to block its access to p53. This conventional understanding of p53-MDM2-ARF functional triangle have guided the direction of p53 research, as well as the development of p53-based therapeutic strategies for the last 30 years. Our increasing knowledge of this triangle during this time, especially through identification of p53-independent functions of MDM2 and ARF, have uncovered many under-appreciated molecular mechanisms connecting these three proteins. Through recognizing both antagonizing and synergizing relationships among them, our consideration for harnessing these relationships to develop effective cancer therapies needs an update accordingly. In this review, we will re-visit the conventional wisdom regarding p53-MDM2-ARF tumor-regulating mechanisms, highlight impactful studies contributing to the modern look of their relationships, and summarize ongoing efforts to target this pathway for effective cancer treatments. A refreshed appreciation of p53-MDM2-ARF network can bring innovative approaches to develop new generations of genetically-informed and clinically-effective cancer therapies.
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Affiliation(s)
- Che-Pei Kung
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
| | - Jason D. Weber
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
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14
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Pant V, Aryal NK, Xiong S, Chau GP, Fowlkes NW, Lozano G. Alterations of the MDM2 C-terminus differentially impact its function in vivo. Cancer Res 2022; 82:1313-1320. [PMID: 35078816 PMCID: PMC8983537 DOI: 10.1158/0008-5472.can-21-2381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/07/2021] [Accepted: 01/20/2022] [Indexed: 01/10/2023]
Abstract
Murine double minute 2 (Mdm2) is the principal E3-ubiquitin ligase for p53 and contains a C2H2C4 type RING domain wherein the last cysteine residue is followed by an evolutionarily conserved 13 amino acid C-terminal tail. Previous studies have indicated that integrity of the C-terminal tail is critical for Mdm2 function. Recently, a mutation extending the MDM2 length by five amino acids was identified and associated with enhanced p53 response in fibroblasts and premature aging in a human patient. To investigate the importance of the conserved Mdm2 C-terminal length on p53 regulatory function in vivo, we engineered three novel mouse alleles using CRISPR-Cas9 technology. Genetic studies with these murine models showed that curtailing Mdm2 C-terminal length by even a single amino acid leads to p53-dependent embryonic lethality. Extension of the Mdm2 C-terminal length by five amino acids (QLTCL) yielded viable mice that are smaller in size, exhibit fertility problems, and have a shortened life span. Analysis of early passage mouse embryonic fibroblasts indicated impaired Mdm2 function correlates with enhanced p53 activity under stress conditions. Furthermore, analysis in mice showed tissue-specific alterations in p53 target gene expression and enhanced radiosensitivity. These results confirm the physiological importance of the evolutionarily conserved Mdm2 C-terminus in regulating p53 functions. SIGNIFICANCE This in vivo study highlights that alterations to the C-terminus of Mdm2 perturb its regulation of the tumor suppressor p53.
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Affiliation(s)
- Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Neeraj K. Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Current address: Oncology R&D, AstraZeneca, 35 Gatehouse Park, Waltham, MA 02451
| | - Shunbin Xiong
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Gilda P Chau
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Natalie W. Fowlkes
- Department of Veterinary Medicine & Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Corresponding author: Guillermina Lozano, PhD, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, Tel. 713 834 6386,
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15
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The roles of mouse double minute 2 (MDM2) oncoprotein in ocular diseases: A review. Exp Eye Res 2022; 217:108910. [PMID: 34998788 DOI: 10.1016/j.exer.2021.108910] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 12/03/2021] [Accepted: 12/21/2021] [Indexed: 12/19/2022]
Abstract
Mouse double minute 2 (MDM2), an E3 ubiquitin ligase and the primary negative regulator of the tumor suppressor p53, cooperates with its structural homolog MDM4/MDMX to control intracellular p53 level. In turn, overexpression of p53 upregulates and forms an autoregulatory feedback loop with MDM2. The MDM2-p53 axis plays a pivotal role in modulating cell cycle control and apoptosis. MDM2 itself is regulated by the PI3K-AKT and RB-E2F-ARF pathways. While amplification of the MDM2 gene or overexpression of MDM2 (due to MDM2 SNP T309G, for instance) is associated with various malignancies, numerous studies have shown that MDM2/p53 alterations may also play a part in the pathogenetic process of certain ocular disorders (Fig. 1). These include cancers (retinoblastoma, uveal melanoma), fibrocellular proliferative diseases (proliferative vitreoretinopathy, pterygium), neovascular diseases, degenerative diseases (cataract, primary open-angle glaucoma, age-related macular degeneration) and infectious/inflammatory diseases (trachoma, uveitis). In addition, MDM2 is implicated in retinogenesis and regeneration after optic nerve injury. Anti-MDM2 therapy has shown potential as a novel approach to treating these diseases. Despite major safety concerns, there are high expectations for the clinical value of reformative MDM2 inhibitors. This review summarizes important findings about the role of MDM2 in ocular pathologies and provides an overview of recent advances in treating these diseases with anti-MDM2 therapies.
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16
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Nagpal I, Yuan ZM. The Basally Expressed p53-Mediated Homeostatic Function. Front Cell Dev Biol 2021; 9:775312. [PMID: 34888311 PMCID: PMC8650216 DOI: 10.3389/fcell.2021.775312] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/08/2021] [Indexed: 01/04/2023] Open
Abstract
Apart from mutations in the p53 gene, p53 functions can be alternatively compromised by a decrease in nuclear p53 protein levels or activities. In accordance, enhanced p53 protein turnover due to elevated expression of the critical p53 E3 ligase MDM2 or MDM2/MDMX is found in many human cancers. Likewise, the HPV viral E6 protein-mediated p53 degradation critically contributes to the tumorigenesis of cervical cancer. In addition, growth-promoting signaling-induced cell proliferation is accompanied by p53 downregulation. Animal studies have also shown that loss of p53 is essential for oncogenes to drive malignant transformation. The close association between p53 downregulation and carcinogenesis implicates a critical role of basally expressed p53. In accordance, available evidence indicates that a reduced level of basal p53 is usually associated with disruption of homeostasis, suggesting a homeostatic function mediated by basal p53. However, basally expressed p53 under non-stress conditions is maintained at a relatively low abundance with little transcriptional activity, raising the question of how basal p53 could protect homeostasis. In this review, we summarize the findings pertinent to basal p53-mediated activities in the hope of developing a model in which basally expressed p53 functions as a barrier to anabolic metabolism to preserve homeostasis. Future investigation is necessary to characterize basal p53 functionally and to obtain an improved understanding of p53 homeostatic function, which would offer novel insight into the role of p53 in tumor suppression.
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Affiliation(s)
- Isha Nagpal
- John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, MA, United States
| | - Zhi-Min Yuan
- John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, MA, United States
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17
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MDM2, MDMX, and p73 regulate cell-cycle progression in the absence of wild-type p53. Proc Natl Acad Sci U S A 2021; 118:2102420118. [PMID: 34716260 DOI: 10.1073/pnas.2102420118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 09/21/2021] [Indexed: 02/08/2023] Open
Abstract
The p53 tumor suppressor protein, known to be critically important in several processes including cell-cycle arrest and apoptosis, is highly regulated by multiple mechanisms, most certifiably the Murine Double Minute 2-Murine Double Minute X (MDM2-MDMX) heterodimer. The role of MDM2-MDMX in cell-cycle regulation through inhibition of p53 has been well established. Here we report that in cells either lacking p53 or expressing certain tumor-derived mutant forms of p53, loss of endogenous MDM2 or MDMX, or inhibition of E3 ligase activity of the heterocomplex, causes cell-cycle arrest. This arrest is correlated with a reduction in E2F1, E2F3, and p73 levels. Remarkably, direct ablation of endogenous p73 produces a similar effect on the cell cycle and the expression of certain E2F family members at both protein and messenger RNA levels. These data suggest that MDM2 and MDMX, working at least in part as a heterocomplex, may play a p53-independent role in maintaining cell-cycle progression by promoting the activity of E2F family members as well as p73, making them a potential target of interest in cancers lacking wild-type p53.
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18
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The ion channel TRPM7 regulates zinc-depletion-induced MDMX degradation. J Biol Chem 2021; 297:101292. [PMID: 34627839 PMCID: PMC8561006 DOI: 10.1016/j.jbc.2021.101292] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/04/2021] [Accepted: 10/06/2021] [Indexed: 12/22/2022] Open
Abstract
Zinc deficiency has been linked to human diseases, including cancer. MDMX, a crucial zinc-containing negative regulator of p53, has been found to be amplified or overexpressed in various cancers and implicated in the cancer initiation and progression. We report here that zinc depletion by the ion chelator TPEN or Chelex resin results in MDMX protein degradation in a ubiquitination-independent and 20S proteasome-dependent manner. Restoration of zinc led to recovery of cellular levels of MDMX. Further, TPEN treatment inhibits growth of the MCF-7 breast cancer cell line, which is partially rescued by overexpression of MDMX. Moreover, in a mass-spectrometry-based proteomics analysis, we identified TRPM7, a zinc-permeable ion channel, as a novel MDMX-interacting protein. TRPM7 stabilizes and induces the appearance of faster migrating species of MDMX on SDS-PAGE. Depletion of TRPM7 attenuates, while TRPM7 overexpression facilitates, the recovery of MDMX levels upon adding back zinc to TPEN-treated cells. Importantly, we found that TRPM7 inhibition, like TPEN treatment, decreases breast cancer cell MCF-7 proliferation and migration. The inhibitory effect on cell migration upon TRPM7 inhibition is also partially rescued by overexpression of MDMX. Together, our data indicate that TRPM7 regulates cellular levels of MDMX in part by modulating the intracellular Zn2+ concentration to promote tumorigenesis.
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19
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Zhang S, Lou J, Li Y, Zhou F, Yan Z, Lyu X, Zhao Y. Recent Progress and Clinical Development of Inhibitors that Block MDM4/p53 Protein-Protein Interactions. J Med Chem 2021; 64:10621-10640. [PMID: 34286973 DOI: 10.1021/acs.jmedchem.1c00940] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MDM4 is a homologue of MDM2, serving cooperatively as the negative regulator of tumor suppressor p53. Under the shadow of MDM2 inhibitors, limited efforts had been put into the discovery of MDM4 modulators. Recent studies of the experimental drug ALRN-6924, a dual MDM4 and MDM2 inhibitor, suggest that concurrent inhibition of MDM4 and MDM2 might be beneficial over only MDM2 inhibition. In view of the present research progress, we summarized published inhibitors of MDM4/p53 interactions including both peptide-based compounds and small molecules. Cocrystal structures of ligand/MDM4 complexes have been examined, and their structural features were compiled and compared in order to show the molecular basis required for high MDM4 binding affinities. Representative examples of small-molecule MDM4 inhibitors were discussed, followed by clinical results of ALRN-6924, together, providing a consolidated reference for further development of MDM4 inhibitors, either dual or selective.
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Affiliation(s)
- Shiyan Zhang
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.,State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Jianfeng Lou
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.,State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Yafang Li
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou, Jiangsu 215123, China.,State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Feilong Zhou
- State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Ziqin Yan
- State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Xilin Lyu
- State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Yujun Zhao
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.,State Key Laboratory of Drug Research and Small-Molecule Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.,School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
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20
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Yu D, Xu Z, Cheng X, Qin J. The role of miRNAs in MDMX-p53 interplay. J Evid Based Med 2021; 14:152-160. [PMID: 33988919 DOI: 10.1111/jebm.12428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 04/16/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023]
Abstract
MicroRNAs (miRNAs) are endogenous noncoding RNAs of 19-24 nucleotides in length and are tightly related to tumorigenesis and progression. Recent studies have demonstrated that the tumor suppressor p53 and its negative controller MDMX are regulated by miRNAs in different ways. Some miRNAs directly target p53 and regulate its expression and function, whereas some miRNAs target MDMX and regulate p53's activity indirectly. The overexpression of several miRNAs can restore the activity of p53 by negatively regulating MDMX in cancer cells. Therefore, a better understanding of the miRNAs-MDMX-p53 network will put forward potential research directions for developing anticancer therapeutics. In the present review, we mainly focus on the regulatory effects of miRNAs on the MDMX-p53 interplay as well as the role of the miRNAs-MDMX-p53 network in human cancer.
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Affiliation(s)
- Dehua Yu
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhiyuan Xu
- Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, China
| | - Xiangdong Cheng
- Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, China
| | - Jiangjiang Qin
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, China
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21
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Klein AM, de Queiroz RM, Venkatesh D, Prives C. The roles and regulation of MDM2 and MDMX: it is not just about p53. Genes Dev 2021; 35:575-601. [PMID: 33888565 PMCID: PMC8091979 DOI: 10.1101/gad.347872.120] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this review, Klein et al. discuss the p53-independent roles of MDM2 and MDMX. First, they review the structural and functional features of MDM2 and MDMX proteins separately and together that could be relevant to their p53-independent activities. Following this, they summarize how these two proteins are regulated and how they can function in cells that lack p53. Most well studied as proteins that restrain the p53 tumor suppressor protein, MDM2 and MDMX have rich lives outside of their relationship to p53. There is much to learn about how these two proteins are regulated and how they can function in cells that lack p53. Regulation of MDM2 and MDMX, which takes place at the level of transcription, post-transcription, and protein modification, can be very intricate and is context-dependent. Equally complex are the myriad roles that these two proteins play in cells that lack wild-type p53; while many of these independent outcomes are consistent with oncogenic transformation, in some settings their functions could also be tumor suppressive. Since numerous small molecules that affect MDM2 and MDMX have been developed for therapeutic outcomes, most if not all designed to prevent their restraint of p53, it will be essential to understand how these diverse molecules might affect the p53-independent activities of MDM2 and MDMX.
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Affiliation(s)
- Alyssa M Klein
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University, New York, New York 10032, USA
| | | | - Divya Venkatesh
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Carol Prives
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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22
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Li F, Yu S, Huang X, Dong C, Ren J. Studying Homo-oligomerization and Hetero-oligomerization of MDMX and MDM2 Proteins in Single Living Cells by Using In Situ Fluorescence Correlation Spectroscopy. Biochemistry 2021; 60:1498-1505. [PMID: 33870698 DOI: 10.1021/acs.biochem.1c00153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protein oligomerization plays a very important role in many physiological processes. p53 acts as a key tumor suppressor by regulating cell cycle arrest, DNA repair, and apoptosis, and its antitumor activity is regulated by the hetero- and homo-oligomerization of MDMX and MDM2 proteins. So far, some traditional methods have been utilized to study the oligomerization of MDMX and MDM2 in vitro, but they have not clarified some controversial issues or whether the extracellular results can represent the intracellular results. Here, we put forward an in situ method for studying protein homo- and hetero-oligomerization in single living cells by using fluorescence correlation spectroscopy. In this study, MDMX and MDM2 were labeled with fluorescent proteins using lentiviral transfection. Autocorrelation spectroscopy and cross-correlation spectroscopy methods were used to study the oligomerization of MDMX and MDM2 in situ and the effect of regulation of MDMX oligomerization on p53-MDMX interactions in single living cells. We observed the homo- and hetero-oligomerization of MDMX and MDM2 in living cells. Meanwhile, the levels of the homo-oligomers of MDMX and MDM2 were increased due to the lack of hetero-oligomerization. Finally, the binding affinity of MDMX for p53 was improved with an increase in the level of MDMX hetero-oligomerization.
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Affiliation(s)
- Fucai Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Shengrong Yu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Xiangyi Huang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Chaoqing Dong
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Jicun Ren
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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Yang J, Jin A, Han J, Chen X, Zheng J, Zhang Y. MDMX Recruits UbcH5c to Facilitate MDM2 E3 Ligase Activity and Subsequent p53 Degradation In Vivo. Cancer Res 2021; 81:898-909. [PMID: 33277368 PMCID: PMC8026549 DOI: 10.1158/0008-5472.can-20-0790] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 10/21/2020] [Accepted: 12/01/2020] [Indexed: 11/16/2022]
Abstract
MDM2 regulates p53 degradation by functioning as an E3 ubiquitin ligase. The role of MDMX, an MDM2 homolog that lacks E3 ligase activity, in the regulation of p53 degradation remains incompletely understood and sometime controversial. This confusion is due at least in part to studies of p53 degradation mainly carried out in in vitro settings, as elimination of either MDM2 or MDMX from mice results in p53-dependent embryonic lethality, thus obfuscating in vivo studies of the individual roles of MDM2 and MDMX in p53 degradation. To overcome this problem, we generated mice expressing an inducible p53 allele under various MDM2 and MDMX deletion and mutation statuses and studied in vivo p53 degradation. Degradation of p53 in vivo was largely prevented in mice and mouse embryonic fibroblast retaining MDM2 but lacking MDMX. Although MDM2 and MDMX interacted with p53 in the absence of each other, they bound p53 more efficiently as a heterodimer. MDMX, but not MDM2, interacted with ubiquitin-conjugating enzyme UbcH5c, an interaction that was essential for MDMX to enable MDM2 E3 ligase activity for p53 degradation. Grafting the C-terminal residues of MDMX to the C-terminus of MDM2 allowed MDM2 to interact with UbcH5c and enhanced MDM2-mediated p53 degradation in the absence of MDMX. Together, these data indicate that MDMX plays an essential role for p53 degradation in vivo by recruiting UbcH5c to facilitate MDM2 E3 ligase function. SIGNIFICANCE: This study provides the first in vivo evidence of MDMX facilitating MDM2-mediated p53 degradation, clarifying its role in the regulation of this critical tumor suppressor.
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Affiliation(s)
- Jing Yang
- Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Jiangsu Province Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Aiwen Jin
- Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jing Han
- Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Jiangsu Province Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Xin Chen
- Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Jiangsu Province Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Junnian Zheng
- Center of Clinical Oncology, Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, Jiangsu, China.
| | - Yanping Zhang
- Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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24
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Yu DH, Xu ZY, Mo S, Yuan L, Cheng XD, Qin JJ. Targeting MDMX for Cancer Therapy: Rationale, Strategies, and Challenges. Front Oncol 2020; 10:1389. [PMID: 32850448 PMCID: PMC7419686 DOI: 10.3389/fonc.2020.01389] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/01/2020] [Indexed: 12/11/2022] Open
Abstract
The oncogene MDMX, also known as MDM4 is a critical negative regulator of the tumor suppressor p53 and has been implicated in the initiation and progression of human cancers. Increasing evidence indicates that MDMX is often amplified and highly expressed in human cancers, promotes cancer cell growth, and inhibits apoptosis by dampening p53-mediated transcription of its target genes. Inhibiting MDMX-p53 interaction has been found to be effective for restoring the tumor suppressor activity of p53. Therefore, MDMX is becoming one of the most promising molecular targets for developing anticancer therapeutics. In the present review, we mainly focus on the current MDMX-targeting strategies and known MDMX inhibitors, as well as their mechanisms of action and in vitro and in vivo anticancer activities. We also propose other potential targeting strategies for developing more specific and effective MDMX inhibitors for cancer therapy.
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Affiliation(s)
- De-Hua Yu
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhi-Yuan Xu
- Institute of Cancer and Basic Medicine, Chinese Academy of Sciences, Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou, China
| | - Shaowei Mo
- First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Li Yuan
- First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiang-Dong Cheng
- Institute of Cancer and Basic Medicine, Chinese Academy of Sciences, Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou, China
| | - Jiang-Jiang Qin
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Cancer and Basic Medicine, Chinese Academy of Sciences, Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou, China
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25
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Kook S, Zhan X, Thibeault K, Ahmed MR, Gurevich VV, Gurevich EV. Mdm2 enhances ligase activity of parkin and facilitates mitophagy. Sci Rep 2020; 10:5028. [PMID: 32193420 PMCID: PMC7081349 DOI: 10.1038/s41598-020-61796-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 02/21/2020] [Indexed: 12/11/2022] Open
Abstract
Loss-of-function mutations in the E3 ubiquitin ligase parkin have been implicated in the death of dopaminergic neurons in the substantia nigra, which is the root cause of dopamine deficit in the striatum in Parkinson's disease. Parkin ubiquitinates proteins on mitochondria that lost membrane potential, promoting the elimination of damaged mitochondria. Neuroprotective activity of parkin has been linked to its critical role in the mitochondria maintenance. Here we report a novel regulatory mechanism: another E3 ubiquitin ligase Mdm2 directly binds parkin and enhances its enzymatic activity in vitro and in intact cells. Mdm2 translocates to damaged mitochondria independently of parkin, enhances parkin-dependent ubiquitination of the outer mitochondria membrane protein mitofusin1. Mdm2 facilitates and its knockdown reduces parkin-dependent mitophagy. Thus, ubiquitously expressed Mdm2 might enhance cytoprotective parkin activity. The data suggest that parkin activation by Mdm2 could be targeted to increase its neuroprotective functions, which has implications for anti-parkinsonian therapy.
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Affiliation(s)
- Seunghyi Kook
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
- Department of Pediatrics, Division of Neonatology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Xuanzhi Zhan
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
- Department of Chemistry, Tennessee Technological University, Cookeville, TN, 38505, USA
| | - Kimberly Thibeault
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Mohamed R Ahmed
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
- Biomaterials and Advanced Drug Delivery Laboratories, Stanford University, Palo Alto, CA, 94304, USA
| | - Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Eugenia V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA.
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26
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Kosztyu P, Slaninová I, Valčíková B, Verlande A, Müller P, Paleček JJ, Uldrijan S. A Single Conserved Amino Acid Residue as a Critical Context-Specific Determinant of the Differential Ability of Mdm2 and MdmX RING Domains to Dimerize. Front Physiol 2019; 10:390. [PMID: 31024344 PMCID: PMC6465955 DOI: 10.3389/fphys.2019.00390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/21/2019] [Indexed: 12/02/2022] Open
Abstract
Mdm2 and MdmX are related proteins serving in the form of the Mdm2 homodimer or Mdm2/MdmX heterodimer as an E3 ubiquitin ligase for the tumor suppressor p53. The dimerization is required for the E3 activity and is mediated by the conserved RING domains present in both proteins, but only the RING domain of Mdm2 can form homodimers efficiently. We performed a systematic mutational analysis of human Mdm2, exchanging parts of the RING with the corresponding MdmX sequence, to identify the molecular determinants of this difference. Mdm2 can also promote MdmX degradation, and we identified several mutations blocking it. They were located mainly at the Mdm2/E2 interface and did not disrupt the MdmX-Mdm2 interaction. Surprisingly, some mutations of the Mdm2/E2 interface inhibited MdmX degradation, which is mediated by the Mdm2/MdmX heterodimer, but did not affect p53 degradation, mediated by the Mdm2 homodimer. Only one mutant, replacing a conserved cysteine 449 with asparagine (C449N), disrupted the ability of Mdm2 to dimerize with MdmX. When we introduced the cysteine residue into the corresponding site in MdmX, the RING domain became capable of forming dimers with other MdmX molecules in vivo, suggesting that one conserved amino acid residue in the RINGs of Mdm2 and MdmX could serve as the determinant of the differential ability of these domains to form dimers and their E3 activity. In immunoprecipitations, however, the homodimerization of MdmX could be observed only when the asparagine residue was replaced with cysteine in both RINGs. This result suggested that heterocomplexes consisting of one mutated MdmX RING with cysteine and one wild-type MdmX RING with asparagine might be less stable, despite being readily detectable in the cell-based assay. Moreover, Mdm2 C449N blocked Mdm2-MdmX heterodimerization but did not disrupt the ability of Mdm2 homodimer to promote p53 degradation, suggesting that the effect of the conserved cysteine and asparagine residues on dimerization was context-specific. Collectively, our results indicate that the effects of individual exchanges of conserved residues between Mdm2 and MdmX RING domains might be context-specific, supporting the hypothesis that Mdm2 RING homodimers and Mdm2-MdmX heterodimers may not be entirely structurally equivalent, despite their apparent similarity.
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Affiliation(s)
- Pavlína Kosztyu
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Iva Slaninová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Barbora Valčíková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czechia
| | - Amandine Verlande
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czechia
| | - Petr Müller
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czechia
| | - Jan J Paleček
- Central European Institute of Technology, Masaryk University, Brno, Czechia.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czechia
| | - Stjepan Uldrijan
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czechia
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27
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Yu F, Jiang Z, Song A. Association of rs11801299 and rs1380576 polymorphisms at MDM4 with risk, clinicopathological features and prognosis in patients with retinoblastoma. Cancer Epidemiol 2019; 58:153-159. [PMID: 30597480 DOI: 10.1016/j.canep.2018.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 10/28/2018] [Accepted: 12/17/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND rs11801299 and rs1380576, two novel polymorphisms in MDM4 gene, have been investigated in several different cancer types. However, the role of these two polymorphisms in retinoblastoma (RB) remains unclear. METHODS A total of 126 patients with primary RB and 148 age-/gender-matched controls were included in this retrospective study. The frequency of rs11801299 and rs1380576 were determined between RB patients and controls. The association of these two polymorphisms with clinicopathological characteristics, prognosis were further evaluated. RESULTS AA genotype at rs11801299 was significantly associated with an increased risk of developing RB (OR = 2.06, 95%CI 1.09-3.90). The possibility of developing RB was also significantly increased in individuals with A allele at rs11801299 (OR = 1.49, 95%CI 1.06-2.08). RB patients carrying AA genotype and A allele at rs11801299 were more likely to have tumor invasion and poor differentiation. As for rs1380576, a significantly lower risk of developing RB was observed in patients with G allele (CG + GG) compared with wild-type CC genotype (OR = 0.59, 95%CI 0.36-3.95). RB patients with GG genotype or G allele had a lower risk of developing highly aggressive cancer. Kaplan-Meier curves and log-rank results revealed that RB patients carrying AA genotype or A allele (AA + GA) at rs11801299 had significantly poorer prognosis. Multivariate COX analysis showed that the rs11801299 G allele was associated with decreased survival but was not an independent prognostic factor. CONCLUSION rs11801299 was significantly associated with RB risk, pathological differentiation, tumor aggressiveness and poor prognosis.
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Affiliation(s)
- Fenghua Yu
- Department of Ophthalmology, Central Hospital of Linyi, Yishui, Shandong, 276400, China
| | - Zhongming Jiang
- Department of Ophthalmology, Central Hospital of Linyi, Yishui, Shandong, 276400, China
| | - Aiping Song
- Department of Ophthalmology, Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, 250014, China.
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28
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Association of Single Nucleotide Polymorphisms of the MDM4 Gene With the Susceptibility to Breast Cancer in a Southeast Iranian Population Sample. Clin Breast Cancer 2018; 18:e883-e891. [DOI: 10.1016/j.clbc.2018.01.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/12/2018] [Accepted: 01/13/2018] [Indexed: 01/14/2023]
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29
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Li D, Tavana O, Sun SC, Gu W. Peli1 Modulates the Subcellular Localization and Activity of Mdmx. Cancer Res 2018; 78:2897-2910. [PMID: 29523541 PMCID: PMC5984691 DOI: 10.1158/0008-5472.can-17-3531] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/12/2018] [Accepted: 03/05/2018] [Indexed: 12/21/2022]
Abstract
Mdm2 and Mdmx, both major repressors of p53 in human cancers, are predominantly localized to the nucleus and cytoplasm, respectively. The mechanism by which subcellular localization of Mdmx is regulated remains unclear. In this study, we identify the E3 ligase Peli1 as a major binding partner and regulator of Mdmx in human cells. Peli1 bound Mdmx in vitro and in vivo and promoted high levels of ubiquitination of Mdmx. Peli1-mediated ubiquitination was degradation-independent, promoting cytoplasmic localization of Mdmx, which in turn resulted in p53 activation. Consistent with this, knockdown or knockout Peli1 in human cancer cells induced nuclear localization of Mdmx and suppressed p53 activity. Myc-induced tumorigenesis was accelerated in Peli1-null mice and associated with downregulation of p53 function. Clinical samples of human cutaneous melanoma had decreased Peli1 expression, which was associated with poor overall survival. Together, these results demonstrate that Peli1 acts as a critical factor for the Mdmx-p53 axis by modulating the subcellular localization and activity of Mdmx, thus revealing a novel mechanism of Mdmx deregulation in human cancers.Significance: Peli1-mediated regulation of Mdmx, a major inhibitor of p53, provides critical insight into activation of p53 function in human cancers. Cancer Res; 78(11); 2897-910. ©2018 AACR.
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Affiliation(s)
- Dawei Li
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Omid Tavana
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Shao-Cong Sun
- Department of Immunology, the University of Texas MD Anderson Cancer Center, MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Wei Gu
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York.
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30
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MDMX acidic domain inhibits p53 DNA binding in vivo and regulates tumorigenesis. Proc Natl Acad Sci U S A 2018; 115:E3368-E3377. [PMID: 29581299 DOI: 10.1073/pnas.1719090115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The MDM2 homolog MDMX oncoprotein is indispensable for inhibition of p53 during normal embryonic development and malignant transformation, yet how MDMX harnesses p53 functions is unclear. In addition to a canonical N-terminal p53-binding domain, recent work suggests the central acidic domain of MDMX regulates p53 interaction through intramolecular mimicry and engages in second-site interaction with the p53 core domain in vitro. To test the physiological relevance of these interactions, we generated an MDMX knockin mouse having substitutions in a conserved WW motif necessary for these functions (W201S/W202G). Notably, MDMXSG cells have normal p53 level but increased p53 DNA binding and target gene expression, and rapidly senesce. In vivo, MDMXSG inhibits early-phase disease in Eµ-Myc transgenic mice but accelerates the onset of lethal lymphoma and shortens overall survival. Therefore, MDMX is an important regulator of p53 DNA binding, which complements the role of MDM2 in regulating p53 level. Furthermore, the results suggest that the WW motif has dual functions that regulate p53 and inhibit Myc-driven lymphomas independent of p53.
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31
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Chopra H, Khan Z, Contreras J, Wang H, Sedrak A, Zhu Y. Activation of p53 and destabilization of androgen receptor by combinatorial inhibition of MDM2 and MDMX in prostate cancer cells. Oncotarget 2017; 9:6270-6281. [PMID: 29464071 PMCID: PMC5814211 DOI: 10.18632/oncotarget.23569] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 10/13/2017] [Indexed: 01/22/2023] Open
Abstract
Castration-resistant prostate cancer (CRPC) frequently develops after initial standard radiation and androgen deprivation therapy, leaving patients with limited further treatment options. Androgen receptor (AR) is a transcription factor that plays a key role in the initiation and progression of prostate cancer. p53, a major tumor suppressor that is rarely mutated in early-stages of prostate cancer, is often deregulated during prostate cancer progression. Here, we report an unusual co-amplification of MDM2 and MDMX, two crucial negative regulators of p53, in CRPC datasets. We demonstrate that combinatorial inhibition of MDM2 and MDMX, with nutlin-3 and NSC207895 respectively, has a profound inhibitory effect on cell proliferation of androgen-responsive, wild-type TP53 gene carrying prostate cancer cells LNCaP and 22Rv1. We further show that the combinatorial inhibition of MDM2 and MDMX not only activates p53, but also decreases cellular levels of AR and represses its function. Additionally, co-expression of MDM2 and MDMX stabilizes AR. Together, our results indicate that combinatorial inhibition of MDM2 and MDMX may offer a novel compelling strategy for prostate cancer therapy.
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Affiliation(s)
- Harman Chopra
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Zara Khan
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Jamie Contreras
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Herui Wang
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Abanob Sedrak
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Yan Zhu
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
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32
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Chee SMQ, Wongsantichon J, Siau J, Thean D, Ferrer F, Robinson RC, Lane DP, Brown CJ, Ghadessy FJ. Structure-activity studies of Mdm2/Mdm4-binding stapled peptides comprising non-natural amino acids. PLoS One 2017; 12:e0189379. [PMID: 29228061 PMCID: PMC5724825 DOI: 10.1371/journal.pone.0189379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/24/2017] [Indexed: 11/24/2022] Open
Abstract
As primary p53 antagonists, Mdm2 and the closely related Mdm4 are relevant cancer therapeutic targets. We have previously described a series of cell-permeable stapled peptides that bind to Mdm2 with high affinity, resulting in activation of the p53 tumour suppressor. Within this series, highest affinity was obtained by modification of an obligate tryptophan residue to the non-natural L-6-chlorotryptophan. To understand the structural basis for improved affinity we have solved the crystal structure of this stapled peptide (M011) bound to Mdm2 (residues 6–125) at 1.66 Å resolution. Surprisingly, near identity to the structure of a related peptide (M06) without the 6-chloro modification is observed. Further analysis of linear and stapled peptides comprising 6-Me-tryptophan provides mechanistic insight into dual Mdm2/Mdm4 antagonism and confirms L98 of Mdm4 as a mutable steric gate. The results also highlight a possible role of the flexible hinge region in determining Mdm2/Mdm4 plasticity.
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Affiliation(s)
- Sharon Min Qi Chee
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | | | - Jiawei Siau
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Dawn Thean
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Fernando Ferrer
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Robert C. Robinson
- Institute of Molecular and Cellular Biology, A*STAR, Singapore, Singapore
| | - David P. Lane
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Christopher J. Brown
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
- * E-mail: (CJB); (FJG)
| | - Farid J. Ghadessy
- p53Lab, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
- * E-mail: (CJB); (FJG)
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33
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Chan JV, Ping Koh DX, Liu Y, Joseph TL, Lane DP, Verma CS, Tan YS. Role of the N-terminal lid in regulating the interaction of phosphorylated MDMX with p53. Oncotarget 2017; 8:112825-112840. [PMID: 29348869 PMCID: PMC5762554 DOI: 10.18632/oncotarget.22829] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023] Open
Abstract
Murine double minute 4 protein (MDMX) is crucial for the regulation of the tumor suppressor protein p53. Phosphorylation of the N-terminal domain of MDMX is thought to affect its binding with the transactivation domain of p53, thus playing a role in p53 regulation. In this study, the effects of MDMX phosphorylation on the binding of p53 were investigated using molecular dynamics simulations. It is shown that in addition to the previously proposed mechanism in which phosphorylated Y99 of MDMX inhibits p53 binding through steric clash with P27 of p53, the N-terminal lid of MDMX also appears to play an important role in regulating the phosphorylation-dependent interactions between MDMX and p53. In the proposed mechanism, phosphorylated Y99 aids in pulling the lid into the p53-binding pocket, thus inhibiting the binding between MDMX and p53. Rebinding of p53 appears to be facilitated by the subsequent phosphorylation of Y55, which draws the lid away from the binding pocket by electrostatic attraction of the lid's positively charged N-terminus. The ability to target these mechanisms for the proper regulation of p53 could have important implications for understanding cancer biology and for drug development.
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Affiliation(s)
- Jane Vin Chan
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore
| | - Dawn Xin Ping Koh
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore
| | - Yun Liu
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore
| | - Thomas L Joseph
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore
| | - David P Lane
- p53 Laboratory, Agency for Science, Technology and Research (ASTAR), Singapore
| | - Chandra S Verma
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore.,Department of Biological Sciences, National University of Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yaw Sing Tan
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore
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34
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Tian H, Tackmann NR, Jin A, Zheng J, Zhang Y. Inactivation of the MDM2 RING domain enhances p53 transcriptional activity in mice. J Biol Chem 2017; 292:21614-21622. [PMID: 29123033 DOI: 10.1074/jbc.ra117.000122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/02/2017] [Indexed: 01/08/2023] Open
Abstract
The MDM2 RING domain harbors E3 ubiquitin ligase activity critical for regulating the degradation of tumor suppressor p53, which controls many cellular pathways. The MDM2 RING domain also is required for an interaction with MDMX. Mice containing a substitution in the MDM2 RING domain, MDM2C462A, disrupting MDM2 E3 function and the MDMX interaction, die during early embryogenesis that can be rescued by p53 deletion. To investigate whether MDM2C462A, which retains p53 binding, has p53-suppressing activity, we generated Mdm2C462A/C462A ;p53ER/- mice, in which we replaced the endogenous p53 alleles with an inducible p53ER/- allele, and compared survival with that of similarly generated Mdm2-/-;p53ER/- mice. Adult Mdm2-null mice died ∼7 days after tamoxifen-induced p53 activation, indicating that in the absence of MDM2, MDMX cannot suppress p53. Surprisingly, Mdm2C462A/C462A ;p53ER/- mice died ∼5 days after tamoxifen injection, suggesting that p53 activity is higher in the presence of MDM2C462A than in the absence of MDM2. Indeed, in MDM2C462A-expressing mouse tissues and embryonic fibroblasts, p53 exhibited higher transcriptional activity than in those expressing no MDM2 or no MDM2 and MDMX. This observation indicated that MDM2C462A not only is unable to suppress p53 but may have gained the ability to enhance p53 activity. We also found that p53 acetylation, a measure of p53 transcriptional activity, was higher in the presence of MDM2C462A than in the absence of MDM2. These results reveal an unexpected role of MDM2C462A in enhancing p53 activity and suggest the possibility that compounds targeting MDM2 RING domain function could produce even more robust p53 activation.
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Affiliation(s)
- Hui Tian
- From the Department of Radiation Oncology, Lineberger Comprehensive Cancer Center and.,the Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
| | - Nicole R Tackmann
- From the Department of Radiation Oncology, Lineberger Comprehensive Cancer Center and.,the Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514 and
| | - Aiwen Jin
- From the Department of Radiation Oncology, Lineberger Comprehensive Cancer Center and
| | - Junnian Zheng
- the Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
| | - Yanping Zhang
- From the Department of Radiation Oncology, Lineberger Comprehensive Cancer Center and .,the Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
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Hauck PM, Wolf ER, Olivos DJ, McAtarsney CP, Mayo LD. The fate of murine double minute X (MdmX) is dictated by distinct signaling pathways through murine double minute 2 (Mdm2). Oncotarget 2017; 8:104455-104466. [PMID: 29262653 PMCID: PMC5732819 DOI: 10.18632/oncotarget.22320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/05/2017] [Indexed: 01/17/2023] Open
Abstract
Mouse double minute 2 (Mdm2) and MdmX dimerize in response to low levels of genotoxic stress to function in a ubiquitinating complex, which signals for destabilization of p53. Under growth conditions, Mdm2 functions as a neddylating ligase, but the importance and extent of MdmX involvement in this process are largely unknown. Here we show that when Mdm2 functions as a neddylating enzyme, MdmX is stabilized. Furthermore, we demonstrate that under growth conditions, MdmX enhances the neddylation activity of Mdm2 on p53 and is a substrate for neddylation itself. Importantly, MdmX knockdown in MCF-7 breast cancer cells resulted in diminished neddylated p53, suggesting that MdmX is important for Mdm2-mediated neddylation. Supporting this finding, the lack of MdmX in transient assays or in p53/MdmX-/- MEFs results in decreased or altered neddylation of p53 respectively; therefore, MdmX is a critical component of the Mdm2-mediated neddylating complex. c-Src is the upstream activator of this Mdm2-MdmX neddylating pathway and loss of Src signaling leads to the destabilization of MdmX that is dependent on the RING (Really Interesting New Gene) domain of MdmX. Treatment with a small molecule inhibitor of neddylation, MLN4924, results in the activation of Ataxia Telangiectasia Mutated (ATM). ATM phosphorylates Mdm2, converting Mdm2 to a ubiquitinating enzyme which leads to the destabilization of MdmX. These data show how distinct signaling pathways engage neddylating or ubiquitinating activities and impact the Mdm2-MdmX axis.
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Affiliation(s)
- Paula M Hauck
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Eric R Wolf
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America
| | - David J Olivos
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Ciaran P McAtarsney
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Lindsey D Mayo
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America.,Indiana University Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America
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36
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Huang C, Wu S, Ji H, Yan X, Xie Y, Murai S, Zhao H, Miyagishi M, Kasim V. Identification of XBP1-u as a novel regulator of the MDM2/p53 axis using an shRNA library. SCIENCE ADVANCES 2017; 3:e1701383. [PMID: 29057323 PMCID: PMC5647124 DOI: 10.1126/sciadv.1701383] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/13/2017] [Indexed: 05/06/2023]
Abstract
Cell cycle progression is a tightly controlled fundamental process in living cells, with any defects being closely linked to various abnormalities. The tumor suppressor p53/p21 axis is a core pathway controlling cell cycle progression; however, its regulatory mechanism has not been fully elucidated. In an effort to unravel this crucial network, we screened a short hairpin RNA expression vector library and identified unspliced X-box binding protein 1 (XBP1-u) as a novel and critical regulator of the p53/p21 axis. Specifically, XBP1-u negatively regulates the p53/p21 axis by enhancing p53 ubiquitination, which in turn down-regulates p21 expression. We show that XBP1-u suppression induces G0-G1 phase arrest and represses cell proliferation. We further report that the carboxyl terminus of XBP1-u, which differs from that of its spliced form (XBP1-s) due to a codon shift, binds and stabilizes mouse double minute homolog 2 (MDM2) protein, a negative regulator of p53, by inhibiting its self-ubiquitination. Concomitantly, XBP-u overexpression enhances tumorigenesis by positively regulating MDM2. Together, our findings suggest that XBP1-u functions far beyond being merely a precursor of XBP1-s and, instead, is involved in fundamental biological processes. Furthermore, this study provides new insights regarding the regulation of the MDM2/p53/p21 axis.
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Affiliation(s)
- Can Huang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Shourong Wu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
- 111 Project Laboratory of Biomechanics and Tissue Repair, College of Bioengineering, Chongqing University, Chongqing 400044, China
- Corresponding author. (V.K.); (S.W.)
| | - Hong Ji
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Xuesong Yan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Yudan Xie
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Saomi Murai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Hezhao Zhao
- Chongqing Cancer Institute, Chongqing 400030, China
| | - Makoto Miyagishi
- Molecular Composite Medicine Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan
| | - Vivi Kasim
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
- 111 Project Laboratory of Biomechanics and Tissue Repair, College of Bioengineering, Chongqing University, Chongqing 400044, China
- Corresponding author. (V.K.); (S.W.)
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37
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Zhang Y, Zeng SX, Hao Q, Lu H. Monitoring p53 by MDM2 and MDMX is required for endocrine pancreas development and function in a spatio-temporal manner. Dev Biol 2017; 423:34-45. [PMID: 28118981 DOI: 10.1016/j.ydbio.2017.01.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 02/06/2023]
Abstract
Although p53 is not essential for normal embryonic development, it plays a pivotal role in many biological and pathological processes, including cell fate determination-dependent and independent events and diseases. The expression and activity of p53 largely depend on its two biological inhibitors, MDM2 and MDMX, which have been shown to form a complex in order to tightly control p53 to an undetectable level during early stages of embryonic development. However, more delicate studies using conditional gene-modification mouse models show that MDM2 and MDMX may function separately or synergistically on p53 regulation during later stages of embryonic development and adulthood in a cell and tissue-specific manner. Here, we report the role of the MDM2/MDMX-p53 pathway in pancreatic islet morphogenesis and functional maintenance, using mouse lines with specific deletion of MDM2 or MDMX in pancreatic endocrine progenitor cells. Interestingly, deletion of MDM2 results in defects of embryonic endocrine pancreas development, followed by neonatal hyperglycemia and lethality, by inducing pancreatic progenitor cell apoptosis and inhibiting cell proliferation. However, unlike MDM2-knockout animals, mice lacking MDMX in endocrine progenitor cells develop normally. But, surprisingly, the survival rate of adult MDMX-knockout mice drastically declines compared to control mice, as blockage of neonatal development of endocrine pancreas by inhibition of cell proliferation and subsequent islet dysfunction and hyperglycemia eventually lead to type 1 diabetes-like disease with advanced diabetic nephropathy. As expected, both MDM2 and MDMX deletion-caused pancreatic defects are completely rescued by loss of p53, verifying the crucial role of the MDM2 and/or MDMX in regulating p53 in a spatio-temporal manner during the development, functional maintenance, and related disease progress of endocrine pancreas. Also, our study suggests a possible mouse model of advanced diabetic nephropathy, which is complementary to other established diabetic models and perhaps useful for the development of anti-diabetes therapies.
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Affiliation(s)
- Yiwei Zhang
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Shelya X Zeng
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Qian Hao
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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38
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Carr MI, Jones SN. Regulation of the Mdm2-p53 signaling axis in the DNA damage response and tumorigenesis. Transl Cancer Res 2016; 5:707-724. [PMID: 28690977 PMCID: PMC5501481 DOI: 10.21037/tcr.2016.11.75] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The p53 tumor suppressor acts as a guardian of the genome in mammalian cells undergoing DNA double strand breaks induced by a various forms of cell stress, including inappropriate growth signals or ionizing radiation. Following damage, p53 protein levels become greatly elevated in cells and p53 functions primarily as a transcription factor to regulate the expression a wide variety of genes that coordinate this DNA damage response. In cells undergoing high amounts of DNA damage, p53 can promote apoptosis, whereas in cells undergoing less damage, p53 promotes senescence or transient cell growth arrest and the expression of genes involved in DNA repair, depending upon the cell type and level of damage. Failure of the damaged cell to undergo growth arrest or apoptosis, or to respond to the DNA damage by other p53-coordinated mechanisms, can lead to inappropriate cell growth and tumorigenesis. In cells that have successfully responded to genetic damage, the amount of p53 present in the cell must return to basal levels in order for the cell to resume normal growth and function. Although regulation of p53 levels and function is coordinated by many proteins, it is now widely accepted that the master regulator of p53 is Mdm2. In this review, we discuss the role(s) of p53 in the DNA damage response and in tumor suppression, and how post-translational modification of Mdm2 regulates the Mdm2-p53 signaling axis to govern p53 activities in the cell.
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Affiliation(s)
- Michael I Carr
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Stephen N Jones
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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39
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Abstract
The p53 tumor suppressor is highly regulated at the level of protein degradation and transcriptional activity. The key players of the pathway, p53, MDM2, and MDMX are present at multiple conformational states that are responsive to regulation by post-translational modifications and protein-protein interactions. The structures of major functional domains of these proteins have been determined, but the mechanisms of several intrinsically disordered regions remain unclear despite their critical roles in signaling and regulation. Recent studies suggest that these disordered regions function in part by dynamic intra molecular interactions with the structured domains to regulate p53 DNA binding, MDM2 ubiquitin E3 ligase activity, and MDMX-p53 binding. These findings provide new insight on how p53 is controlled by various stress signals, and suggest potential targets for the search of allosteric regulators of the p53 pathway.
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Affiliation(s)
- Jiandong Chen
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
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40
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de Polo A, Vivekanandan V, Little JB, Yuan ZM. MDMX under stress: the MDMX-MDM2 complex as stress signals hub. Transl Cancer Res 2016; 5:725-732. [PMID: 30319942 DOI: 10.21037/tcr.2016.12.18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The tumor suppressor p53 plays a central role in safeguarding cellular homeostasis. Upon various types of stress signals such as DNA damage or oncogenic stress, p53 is promptly activated to prevent and repair damages that can threaten the genome stability. The two major negative regulators of p53 are MDM2 and MDMX, two homolog proteins that control p53 activity and turnover, hence keeping it in check during normal cell cycling. In the event of cellular stress, they have to be inhibited in order to relieve p53 from their suppression and allow its activation. As the essential upstream modulator of p53, the MDMX-MDM2 complex integrates multiple signaling pathways regulating p53 response to perturbations of cellular homeostasis. Given its predominantly cytoplasmic localization in normal conditions, we hypothesize that MDMX, rather than MDM2, is the first recipient of signaling cues directed towards the MDMX-MDM2 complex and aimed at modulating p53. In this review we give a synthetic overview of the phosphorylation sites of MDMX that are known to affect its degradation, ubiquitination, intracellular localization and interaction with MDM2 and p53, ultimately modulating the stability and activity of p53. The role of MDMX in response to the main types of cellular stress is also briefly discussed, along with the potential of the MDMX-MDM2 complex as therapeutic target to restore p53 activity.
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Affiliation(s)
- Anna de Polo
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Varunika Vivekanandan
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - John B Little
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Zhi-Min Yuan
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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41
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Gerarduzzi C, de Polo A, Liu XS, El Kharbili M, Little JB, Yuan ZM. Human epidermal growth factor receptor 4 (Her4) Suppresses p53 Protein via Targeting the MDMX-MDM2 Protein Complex: IMPLICATION OF A NOVEL MDMX SER-314 PHOSPHOSITE. J Biol Chem 2016; 291:25937-25949. [PMID: 27777309 DOI: 10.1074/jbc.m116.752303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/03/2016] [Indexed: 12/11/2022] Open
Abstract
Deregulated receptor tyrosine kinase (RTK) signaling is frequently associated with tumorigenesis and therapy resistance, but its underlying mechanisms still need to be elucidated. In this study, we have shown that the RTK human epidermal growth factor receptor 4 (Her4, also known as Erbb4) can inhibit the tumor suppressor p53 by regulating MDMX-mouse double minute 2 homolog (MDM2) complex stability. Upon activation by either overexpression of a constitutively active vector or ligand binding (Neuregulin-1), Her4 was able to stabilize the MDMX-MDM2 complex, resulting in suppression of p53 transcriptional activity, as shown by p53-responsive element-driven luciferase assay and mRNA levels of p53 target genes. Using a phospho-proteomics approach, we functionally identified a novel Her4-induced posttranslational modification on MDMX at Ser-314, a putative phosphorylation site for the CDK4/6 kinase. Remarkably, inhibition of Ser-314 phosphorylation either with Ser-to-Ala substitution or with a specific inhibitor of CDK4/6 kinase blocked Her4-induced stabilization of MDMX-MDM2 and rescued p53 activity. Our study offers insights into the mechanisms of deregulated RTK-induced carcinogenesis and provides the basis for the use of inhibitors targeting RTK-mediated signals for p53 restoration.
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Affiliation(s)
- Casimiro Gerarduzzi
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Anna de Polo
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Xue-Song Liu
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Manale El Kharbili
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
| | - John B Little
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Zhi-Min Yuan
- From the John B. Little Center for Radiation Sciences, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
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42
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Functional characterization of p53 pathway components in the ancient metazoan Trichoplax adhaerens. Sci Rep 2016; 6:33972. [PMID: 27678309 PMCID: PMC5039725 DOI: 10.1038/srep33972] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/06/2016] [Indexed: 01/09/2023] Open
Abstract
The identification of genes encoding a p53 family member and an Mdm2 ortholog in the ancient placozoan Trichoplax adhaerens advocates for the evolutionary conservation of a pivotal stress-response pathway observed in all higher eukaryotes. Here, we recapitulate several key functionalities ascribed to this known interacting protein pair by analysis of the placozoan proteins (Tap53 and TaMdm2) using both in vitro and cellular assays. In addition to interacting with each other, the Tap53 and TaMdm2 proteins are also able to respectively bind human Mdm2 and p53, providing strong evidence for functional conservation. The key p53-degrading function of Mdm2 is also conserved in TaMdm2. Tap53 retained DNA binding associated with p53 transcription activation function. However, it lacked transactivation function in reporter genes assays using a heterologous cell line, suggesting a cofactor incompatibility. Overall, the data supports functional roles for TaMdm2 and Tap53, and further defines the p53 pathway as an evolutionary conserved fulcrum mediating cellular response to stress.
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43
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Teveroni E, Lucà R, Pellegrino M, Ciolli G, Pontecorvi A, Moretti F. Peptides and peptidomimetics in the p53/MDM2/MDM4 circuitry - a patent review. Expert Opin Ther Pat 2016; 26:1417-1429. [DOI: 10.1080/13543776.2017.1233179] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Emanuela Teveroni
- Institute of Cell Biology and Neurobiology, CNR, Roma, Italy
- Institute of Medical Pathology, Catholic University of Roma, Roma, Italy
| | - Rossella Lucà
- Institute of Cell Biology and Neurobiology, CNR, Roma, Italy
| | | | - Germana Ciolli
- Institute of Cell Biology and Neurobiology, CNR, Roma, Italy
- Institute of Medical Pathology, Catholic University of Roma, Roma, Italy
| | - Alfredo Pontecorvi
- Institute of Medical Pathology, Catholic University of Roma, Roma, Italy
| | - Fabiola Moretti
- Institute of Cell Biology and Neurobiology, CNR, Roma, Italy
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Moscetti I, Teveroni E, Moretti F, Bizzarri AR, Cannistraro S. MDM2-MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance. Int J Nanomedicine 2016; 11:4221-9. [PMID: 27621617 PMCID: PMC5012629 DOI: 10.2147/ijn.s114705] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Murine double minute 2 (MDM2) and 4 (MDM4) are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2-MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2-MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD ) in the micromolar range for the MDM2-MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2-MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2-MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation.
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Affiliation(s)
- Ilaria Moscetti
- Biophysics and Nanoscience Centre, Department DEB, Università della Tuscia, Viterbo, Italy
| | - Emanuela Teveroni
- Department of Endocrinology and Metabolism, Università Cattolica di Roma, Roma, Italy; Institute of Cell Biology and Neurobiology, Consiglio Nazionale delle Ricerche (CNR), Roma, Italy
| | - Fabiola Moretti
- Institute of Cell Biology and Neurobiology, Consiglio Nazionale delle Ricerche (CNR), Roma, Italy
| | - Anna Rita Bizzarri
- Biophysics and Nanoscience Centre, Department DEB, Università della Tuscia, Viterbo, Italy
| | - Salvatore Cannistraro
- Biophysics and Nanoscience Centre, Department DEB, Università della Tuscia, Viterbo, Italy
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45
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Mdm2 Phosphorylation Regulates Its Stability and Has Contrasting Effects on Oncogene and Radiation-Induced Tumorigenesis. Cell Rep 2016; 16:2618-2629. [PMID: 27568562 DOI: 10.1016/j.celrep.2016.08.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/17/2016] [Accepted: 08/03/2016] [Indexed: 11/20/2022] Open
Abstract
ATM phosphorylation of Mdm2-S394 is required for robust p53 stabilization and activation in DNA-damaged cells. We have now utilized Mdm2(S394A) knockin mice to determine that phosphorylation of Mdm2-S394 regulates p53 activity and the DNA damage response in lymphatic tissues in vivo by modulating Mdm2 stability. Mdm2-S394 phosphorylation delays lymphomagenesis in Eμ-myc transgenic mice, and preventing Mdm2-S394 phosphorylation obviates the need for p53 mutation in Myc-driven tumorigenesis. However, irradiated Mdm2(S394A) mice also have increased hematopoietic stem and progenitor cell functions, and we observed decreased lymphomagenesis in sub-lethally irradiated Mdm2(S394A) mice. These findings document contrasting effects of ATM-Mdm2 signaling on p53 tumor suppression and reveal that destabilizing Mdm2 by promoting its phosphorylation by ATM would be effective in treating oncogene-induced malignancies, while inhibiting Mdm2-S394 phosphorylation during radiation exposure or chemotherapy would ameliorate bone marrow failure and prevent the development of secondary hematological malignancies.
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46
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MDM2 oligomers: antagonizers of the guardian of the genome. Oncogene 2016; 35:6157-6165. [PMID: 27041565 DOI: 10.1038/onc.2016.88] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 02/08/2023]
Abstract
Over two decades of MDM2 research has resulted in the accumulation of a wealth of knowledge of many aspects of MDM2 regulation and function, particularly with respect to its most prominent target, p53. For example, recent knock-in mouse studies have shown that MDM2 heterooligomer formation with its homolog, MDMX, is necessary and sufficient in utero to suppress p53 but is dispensable during adulthood. However, despite crucial advances such as these, several aspects regarding basic in vivo functions of MDM2 remain unknown. In one such example, although abundant evidence suggests that MDM2 forms homooligomers and heterooligomers with MDMX, the function and regulation of these homo- and heterooligomers in vivo remain incompletely understood. In this review, we discuss the current state of our knowledge of MDM2 oligomerization as well as current efforts to target the MDM2 oligomer as a broad therapeutic option for cancer treatment.
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47
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Swetzig WM, Wang J, Das GM. Estrogen receptor alpha (ERα/ESR1) mediates the p53-independent overexpression of MDM4/MDMX and MDM2 in human breast cancer. Oncotarget 2016; 7:16049-69. [PMID: 26909605 PMCID: PMC4941297 DOI: 10.18632/oncotarget.7533] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/27/2016] [Indexed: 12/31/2022] Open
Abstract
MDM2 and MDM4 are heterodimeric, non-redundant oncoproteins that potently inhibit the p53 tumor suppressor protein. MDM2 and MDM4 also enhance the tumorigenicity of breast cancer cells in in vitro and in vivo models and are overexpressed in primary human breast cancers. Prior studies have characterized Estrogen Receptor Alpha (ERα/ESR1) as a regulator of MDM2 expression and an MDM2- and p53-interacting protein. However, similar crosstalk between ERα and MDM4 has not been investigated. Moreover, signaling pathways that mediate the overexpression of MDM4 in human breast cancer remain to be elucidated. Using the Cancer Genome Atlas (TCGA) breast invasive carcinoma patient cohort, we have analyzed correlations between ERα status and MDM4 and MDM2 expression in primary, treatment-naïve, invasive breast carcinoma samples. We report that the expression of MDM4 and MDM2 is elevated in primary human breast cancers of luminal A/B subtypes and associates with ERα-positive disease, independently of p53 mutation status. Furthermore, in cell culture models, ERα positively regulates MDM4 and MDM2 expression via p53-independent mechanisms, and these effects can be blocked by the clinically-relevant endocrine therapies fulvestrant and tamoxifen. Additionally, ERα also positively regulates p53 expression. Lastly, we report that endogenous MDM4 negatively regulates ERα expression and forms a protein complex with ERα in breast cancer cell lines and primary human breast tumor tissue. This suggests direct signaling crosstalk and negative feedback loops between ERα and MDM4 expression in breast cancer cells. Collectively, these novel findings implicate ERα as a central component of the p53-MDM2-MDM4 signaling axis in human breast cancer.
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Affiliation(s)
- Wendy M. Swetzig
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY, USA
- Department of Molecular Pharmacology and Cancer Therapeutics, The University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Jianmin Wang
- Department of Bioinformatics and Biostatistics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Gokul M. Das
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY, USA
- Department of Molecular Pharmacology and Cancer Therapeutics, The University at Buffalo, State University of New York, Buffalo, NY, USA
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48
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Karni-Schmidt O, Lokshin M, Prives C. The Roles of MDM2 and MDMX in Cancer. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2016; 11:617-44. [PMID: 27022975 DOI: 10.1146/annurev-pathol-012414-040349] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
For more than 25 years, MDM2 and its homolog MDMX (also known as MDM4) have been shown to exert oncogenic activity. These two proteins are best understood as negative regulators of the p53 tumor suppressor, although they may have additional p53-independent roles. Understanding the dysregulation of MDM2 and MDMX in human cancers and how they function either together or separately in tumorigenesis may improve methods of diagnosis and for assessing prognosis. Targeting the proteins themselves, or their regulators, may be a promising therapeutic approach to treating some forms of cancer.
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Affiliation(s)
- Orit Karni-Schmidt
- Department of Biological Sciences, Columbia University, New York, NY 10027;
| | - Maria Lokshin
- Department of Biological Sciences, Columbia University, New York, NY 10027;
| | - Carol Prives
- Department of Biological Sciences, Columbia University, New York, NY 10027;
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Gansmo LB, Bjørnslett M, Halle MK, Salvesen HB, Dørum A, Birkeland E, Hveem K, Romundstad P, Vatten L, Lønning PE, Knappskog S. The MDM4 SNP34091 (rs4245739) C-allele is associated with increased risk of ovarian-but not endometrial cancer. Tumour Biol 2016; 37:10697-702. [PMID: 26867771 PMCID: PMC4999457 DOI: 10.1007/s13277-016-4940-2] [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: 11/17/2015] [Accepted: 01/29/2016] [Indexed: 12/17/2022] Open
Abstract
The MDM4 protein (also known as MDMX or HDMX) is a negative regulator of p53, not only by direct interaction but also through its interaction with MDM2. Further, MDM4 overexpression and amplification have been observed in several cancer forms. Recently, a single nucleotide polymorphism (SNP) in the 3’ untranslated region of the MDM4 gene, SNP34091A > C (rs4245739) was reported to alter MDM4 messenger RNA (mRNA) stability by modulating a microRNA binding site, thereby leading to decreased MDM4 levels. In this case-control study, we aimed to evaluate the possible association between MDM4 SNP34091 status and cancer risk by comparing the genotype frequencies in large hospital-based cohorts of endometrial- (n = 1404) and ovarian (n = 1385) cancer patients with healthy female controls (n = 1870). Genotype frequencies were compared by odds ratio (OR) estimates and Fisher exact tests. We found that individuals harboring the MDM4 SNP34091AC/CC genotypes had a significantly elevated risk for serous ovarian cancer (SOC) in general and high-grade serous ovarian cancer (HGSOC) in particular (SOC: OR = 1.18., 95 % CI = 1.01–1.39; HGSOC: OR = 1.25, CI = 1.02–1.53). No association between SNP34091 genotypes and endometrial cancer risk was observed. Our data indicate the MDM4 SNP34091AC/CC genotypes to be associated with an elevated risk for SOC and in particular the HGSOC type.
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MESH Headings
- 3' Untranslated Regions/genetics
- Adenocarcinoma, Clear Cell/epidemiology
- Adenocarcinoma, Clear Cell/genetics
- Adenocarcinoma, Mucinous/epidemiology
- Adenocarcinoma, Mucinous/genetics
- Alleles
- Carcinoma, Endometrioid/epidemiology
- Carcinoma, Endometrioid/genetics
- Case-Control Studies
- Cell Cycle Proteins
- Cystadenocarcinoma, Serous/epidemiology
- Cystadenocarcinoma, Serous/genetics
- Endometrial Neoplasms/epidemiology
- Endometrial Neoplasms/genetics
- Female
- Gene Frequency
- Genes, Neoplasm
- Genetic Predisposition to Disease
- Genotype
- Humans
- Neoplasm Proteins/genetics
- Norway/epidemiology
- Nuclear Proteins/genetics
- Odds Ratio
- Ovarian Neoplasms/epidemiology
- Ovarian Neoplasms/genetics
- Polymorphism, Single Nucleotide
- Proto-Oncogene Proteins/genetics
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Affiliation(s)
- Liv B Gansmo
- Section of Oncology, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | - Merete Bjørnslett
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Mari Kyllesø Halle
- Department of Gynecology and Obstetrics, Haukeland University Hospital, Bergen, Norway
- Center for Cancer Biomarkers CCBIO, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Helga B Salvesen
- Department of Gynecology and Obstetrics, Haukeland University Hospital, Bergen, Norway
- Center for Cancer Biomarkers CCBIO, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Anne Dørum
- Department of Gynecologic Oncology, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway
| | - Einar Birkeland
- Section of Oncology, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | - Kristian Hveem
- Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Pål Romundstad
- Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lars Vatten
- Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Per Eystein Lønning
- Section of Oncology, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | - Stian Knappskog
- Section of Oncology, Department of Clinical Science, University of Bergen, Bergen, Norway.
- Department of Oncology, Haukeland University Hospital, Bergen, Norway.
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Abstract
p53 has been studied intensively as a major tumour suppressor that detects oncogenic events in cancer cells and eliminates them through senescence (a permanent non-proliferative state) or apoptosis. Consistent with this role, p53 activity is compromised in a high proportion of all cancer types, either through mutation of the TP53 gene (encoding p53) or changes in the status of p53 modulators. p53 has additional roles, which may overlap with its tumour-suppressive capacity, in processes including the DNA damage response, metabolism, aging, stem cell differentiation and fertility. Moreover, many mutant p53 proteins, termed 'gain-of-function' (GOF), acquire new activities that help drive cancer aggression. p53 is regulated mainly through protein turnover and operates within a negative-feedback loop with its transcriptional target, MDM2 (murine double minute 2), an E3 ubiquitin ligase which mediates the ubiquitylation and proteasomal degradation of p53. Induction of p53 is achieved largely through uncoupling the p53-MDM2 interaction, leading to elevated p53 levels. Various stress stimuli acting on p53 (such as hyperproliferation and DNA damage) use different, but overlapping, mechanisms to achieve this. Additionally, p53 activity is regulated through critical context-specific or fine-tuning events, mediated primarily through post-translational mechanisms, particularly multi-site phosphorylation and acetylation. In the present review, I broadly examine these events, highlighting their regulatory contributions, their ability to integrate signals from cellular events towards providing most appropriate response to stress conditions and their importance for tumour suppression. These are fascinating aspects of molecular oncology that hold the key to understanding the molecular pathology of cancer and the routes by which it may be tackled therapeutically.
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