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Feng Y, Xuan X, Hu Y, Lu J, Dong Z, Sun Z, Yao H, Hu L, Yin Q, Liu Y, Wang H. Targeting G-rich sequence to regulate the transcription of murine double minute (MDM) genes in triple-negative breast cancers. Eur J Med Chem 2024; 267:116156. [PMID: 38295687 DOI: 10.1016/j.ejmech.2024.116156] [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: 11/20/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 02/25/2024]
Abstract
Murine double minute 2 (MDM2) and homologous protein murine double minute X (MDMX) are p53 negative regulators that perform significant driving effects in tumorigenesis, and targeting these oncoproteins has became an efficient strategy in treating cancers. However, the definite antitumor activity and significance ordering of each protein in MDM family is still unclear due to the similar structure and complicated regulation. Herein, we identified two G-rich sequences (G1 and G5) located in the promoter that could assemble the G-quadruplex to respectively inhibit and promote the transcription of the MDM2 and MDMX. Based on this target, we designed and synthesized a novel G-quadruplex ligand A3f and achieved the differentiated regulation of MDM protein. In triple-negative breast cancer (TNBC) cells, A3f could induce MDM2-dependent proliferation arrest and exhibit additive therapeutic effect with MDMX inhibitors. Overall, this study provided a novel strategy to regulate the transcription of MDM genes by targeting certain G-rich sequences, and discovered an active antitumor molecule for use in TNBC treatment.
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Affiliation(s)
- Yuxin Feng
- 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
| | - Xuan Xuan
- 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
| | - Jiaguo 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
| | - 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
| | - Ziqiang Sun
- School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, China
| | - Hongying Yao
- 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
| | - Lei Hu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - 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.
| | - Yi Liu
- School of Chemistry and Chemical Engineering, 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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Jia Y, Li Y, Shang H, Luo Y, Tian Y. Ganoderic Acid A and Its Amide Derivatives as Potential Anti-Cancer Agents by Regulating the p53-MDM2 Pathway: Synthesis and Biological Evaluation. Molecules 2023; 28:molecules28052374. [PMID: 36903622 PMCID: PMC10004777 DOI: 10.3390/molecules28052374] [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: 02/08/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
The mechanisms of action of natural products and the identification of their targets have long been a research hotspot. Ganoderic acid A (GAA) is the earliest and most abundant triterpenoids discovered in Ganoderma lucidum. The multi-therapeutic potential of GAA, in particular its anti-tumor activity, has been extensively studied. However, the unknown targets and associated pathways of GAA, together with its low activity, limit in-depth research compared to other small molecule anti-cancer drugs. In this study, GAA was modified at the carboxyl group to synthesize a series of amide compounds, and the in vitro anti-tumor activities of the derivatives were investigated. Finally, compound A2 was selected to study its mechanism of action because of its high activity in three different types of tumor cell lines and low toxicity to normal cells. The results showed that A2 could induce apoptosis by regulating the p53 signaling pathway and may be involved in inhibiting the interaction of MDM2 and p53 by binding to MDM2 (KD = 1.68 µM). This study provides some inspiration for the research into the anti-tumor targets and mechanisms of GAA and its derivatives, as well as for the discovery of active candidates based on this series.
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Wang Q, Li J, Zhu J, Mao J, Duan C, Liang X, Zhu L, Zhu M, Zhang Z, Lin F, Guo R. Genome-wide CRISPR/Cas9 screening for therapeutic targets in NSCLC carrying wild-type TP53 and receptor tyrosine kinase genes. Clin Transl Med 2022; 12:e882. [PMID: 35692096 PMCID: PMC9189421 DOI: 10.1002/ctm2.882] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 04/21/2022] [Accepted: 05/03/2022] [Indexed: 11/25/2022] Open
Abstract
Background Targeted drugs have greatly improved the therapeutic outcome of non‐small cell lung cancer (NSCLC) patients compared with conventional chemotherapy, whereas about one‐third of patients are so far not suitable for targeted therapy due to lack of known driver oncogenes such as a mutated receptor tyrosine kinase (RTK) genes. In this study, we aimed to identify therapeutic targets for this subgroup of NSCLC patients. Methods We performed genome‐wide CRISPR/Cas9 screens in two NSCLC cell lines carrying wild‐type TP53 and receptor tyrosine kinase (wtTP53‐RTK) genes using a GeCKO v2.0 lentiviral library (containing 123411 sgRNAs and targeting 19050 genes). MAGeCKFlute was used to analyse and identify candidate genes. Genetic perturbation and pharmacological inhibition were used to validate the result in vitro and in vivo. Results The Genome‐wide CRISPR/Cas9 screening identified MDM2 as a potential therapeutic target for wtTP53‐RTK NSCLC. Genetic and pharmacological inhibition of MDM2 reduced cell proliferation and impaired tumour growth in the xenograft model, thus confirming the finding of the CRISPR/Cas9 screening. Moreover, treatment by a selective MDM2 inhibitor RG7388 triggered both cell cycle arrest and apoptosis in several NSCLC cell lines. Additionally, RG7388 and pemetrexed synergistically blocked the cell proliferation and growth of wtTP53‐RTK tumours but had limited effects for other genotypes. Conclusions We identified MDM2 as an essential gene and a potential therapeutic target in wtTP53‐RTK NSCLC via a genome‐wide CRISPR/Cas9 screening. For this subgroup, treatment by RG7388 alone or by its combination with pemetrexed resulted in significant tumour inhibition.
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Affiliation(s)
- Qianqian Wang
- Department of Oncologythe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Jun Li
- Department of Oncologythe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Jing Zhu
- Department of Oncologythe Affiliated Jiangning Hospital of Nanjing Medical UniversityNanjingChina
| | - Jiaqi Mao
- Department of Cell BiologySchool of Basic Medical SciencesInstitute for Brain Tumors & Key Laboratory of Rare Metabolic DiseasesNanjing Medical UniversityNanjingChina
| | - Chao Duan
- Department of Cell BiologySchool of Basic Medical SciencesInstitute for Brain Tumors & Key Laboratory of Rare Metabolic DiseasesNanjing Medical UniversityNanjingChina
| | - Xiao Liang
- Department of Oncologythe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Lingyun Zhu
- Department of Cell BiologySchool of Basic Medical SciencesInstitute for Brain Tumors & Key Laboratory of Rare Metabolic DiseasesNanjing Medical UniversityNanjingChina
| | - Mengyan Zhu
- Department of BioinformaticsNanjing Medical UniversityNanjingChina
| | - Zhihong Zhang
- Department of Pathologythe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Fan Lin
- Department of Cell BiologySchool of Basic Medical SciencesInstitute for Brain Tumors & Key Laboratory of Rare Metabolic DiseasesNanjing Medical UniversityNanjingChina
| | - Renhua Guo
- Department of Oncologythe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
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Nicholls PK, Page DC. Germ cell determination and the developmental origin of germ cell tumors. Development 2021; 148:239824. [PMID: 33913479 DOI: 10.1242/dev.198150] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In each generation, the germline is tasked with producing somatic lineages that form the body, and segregating a population of cells for gametogenesis. During animal development, when do cells of the germline irreversibly commit to producing gametes? Integrating findings from diverse species, we conclude that the final commitment of the germline to gametogenesis - the process of germ cell determination - occurs after primordial germ cells (PGCs) colonize the gonads. Combining this understanding with medical findings, we present a model whereby germ cell tumors arise from cells that failed to undertake germ cell determination, regardless of their having colonized the gonads. We propose that the diversity of cell types present in these tumors reflects the broad developmental potential of migratory PGCs.
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Affiliation(s)
- Peter K Nicholls
- Whitehead Institute, 455 Main Street, Cambridge, MA 02142, USA.,Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - David C Page
- Whitehead Institute, 455 Main Street, Cambridge, MA 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Howard Hughes Medical Institute, Whitehead Institute, Cambridge, MA 02142, USA
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Caggiano C, Guida E, Todaro F, Bielli P, Mori M, Ghirga F, Quaglio D, Botta B, Moretti F, Grimaldi P, Rossi P, Jannini EA, Barchi M, Dolci S. Sempervirine inhibits RNA polymerase I transcription independently from p53 in tumor cells. Cell Death Discov 2020; 6:111. [PMID: 33298840 PMCID: PMC7595235 DOI: 10.1038/s41420-020-00345-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/05/2020] [Indexed: 12/18/2022] Open
Abstract
In the search of small molecules that can target MDM2/p53 pathway in testicular germ cell tumors (TGCTs), we identified sempervirine (2,3,4,13-tetrahydro-1H-benz[g]indolo[2,3-a]quinolizin-6-ium), an alkaloid of Gelsemium sempervirens, that has been previously proposed as an inhibitor of MDM2 that targets p53-wildtype (wt) tumor cells. We found that sempervirine not only affects cell growth of p53-wt cancer cells, but it is also active in p53-mutated and p53-null cells by triggering p53-dependent and independent pathways without affecting non-transformed cells. To understand which mechanism/s could be activated both in p53-wt and -null cells, we found that sempervirine induced nucleolar remodeling and nucleolar stress by reducing protein stability of RPA194, the catalytic subunit of RNA polymerase I, that led to rRNA synthesis inhibition and to MDM2 block. As shown for other cancer cell models, MDM2 inhibition by nucleolar stress downregulated E2F1 protein levels both in p53-wt and p53-null TGCT cells with the concomitant upregulation of unphosphorylated pRb. Finally, we show that sempervirine is able to enter the nucleus and accumulates within the nucleolus where it binds rRNA without causing DNA damage. Our results identify semperivirine as a novel rRNA synthesis inhibitor and indicate this drug as a non-genotoxic anticancer small molecule.
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Affiliation(s)
- Cinzia Caggiano
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Eugenia Guida
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Federica Todaro
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Pamela Bielli
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Francesca Ghirga
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Deborah Quaglio
- Department of Chemistry and Drug Technology, University of Rome La Sapienza, Rome, Italy
| | - Bruno Botta
- Department of Chemistry and Drug Technology, University of Rome La Sapienza, Rome, Italy
| | - Fabiola Moretti
- Institute of Cell Biology and Neurobiology, National Research Council of Italy (CNR), Rome, Italy
| | - Paola Grimaldi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Pellegrino Rossi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | | | - Marco Barchi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
| | - Susanna Dolci
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
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Silva-Carvalho AÉ, Alencar APD, Resende MR, da Costa DF, Nonino A, Neves FAR, Saldanha-Araujo F. Epigenetic priming by EHMT1/EHMT2 in acute lymphoblastic leukemia induces TP53 and TP73 overexpression and promotes cell death. Toxicol In Vitro 2020; 69:104992. [PMID: 32889036 DOI: 10.1016/j.tiv.2020.104992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/19/2020] [Accepted: 08/29/2020] [Indexed: 01/25/2023]
Abstract
Euchromatic histone-lysine N-methyltransferase 1 (EHMT1) and EHMT2 are upregulated in various human cancers, and their deregulation is associated with tumor development and progression. In this paper, we investigated the expression level of EHMT1/EHMT2 in acute lymphoblastic leukemia (ALL) and whether the modulation of these enzymes could have any cellular or molecular impact on ALL cells. For this, we used UNC0646 as a priming strategy to target EHMT1/EHMT2 and investigated its effect on proliferation and cell viability of Jurkat cells by MTT assay. Then, considering the IC50 and IC75, cellular death was determined by Annexin V/PI staining using flow cytometry. Finally, we investigated by RT-PCR the molecular bases that could be involved in the observed effects. Interestingly, accessing the International Microarray Innovations in Leukemia (MILE) study group, we detected that both EHMT1 and EHMT2 are overexpressed in ALL. More important, we determined that inhibition of EHMT1/EHMT2 significantly decreased Jurkat cell viability in a dose-dependent manner. Accordingly, we observed that inhibition of EHMT1/EHMT2 promoted Jurkat cell death, which was accompanied by increased expression of P53, TP73, BAX, and MDM4. These results clearly indicate that inhibition of EHMT1/EHMT2 induces pro-apoptotic gene expression in ALL and promotes cell death. More importantly, the modulation of these histone methyltransferases may be a promising epigenetic target for ALL treatment.
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Affiliation(s)
- Amandda Évelin Silva-Carvalho
- Laboratório de Farmacologia Molecular, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil; Laboratório de Hematologia e Células-tronco, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil
| | - Ana Paula Dorneles Alencar
- Laboratório de Farmacologia Molecular, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil; Laboratório de Hematologia e Células-tronco, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil
| | - Marielly Reis Resende
- Laboratório de Farmacologia Molecular, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil; Laboratório de Hematologia e Células-tronco, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil
| | - Daniel Freitas da Costa
- Laboratório de Hematologia e Células-tronco, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil
| | - Alexandre Nonino
- Hospital de Base do Distrito Federal, Setor Hospitalar Sul, Área Especial, Quadra 101, Brasília, DF 70.330-150, Brazil
| | - Francisco Assis Rocha Neves
- Laboratório de Farmacologia Molecular, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil
| | - Felipe Saldanha-Araujo
- Laboratório de Farmacologia Molecular, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil; Laboratório de Hematologia e Células-tronco, Universidade de Brasília, Av. L2 Norte, Brasília, DF 70.910-900, Brazil.
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Huang Q, Chen L, Schonbrunn E, Chen J. MDMX inhibits casein kinase 1α activity and stimulates Wnt signaling. EMBO J 2020; 39:e104410. [PMID: 32511789 DOI: 10.15252/embj.2020104410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/20/2022] Open
Abstract
Casein kinase 1 alpha (CK1α) is a serine/threonine kinase with numerous functions, including regulating the Wnt/β-catenin and p53 pathways. CK1α has a well-established role in inhibiting the p53 tumor suppressor by binding to MDMX and stimulating MDMX-p53 interaction. MDMX purified from cells contains near-stoichiometric amounts of CK1α, suggesting that MDMX may in turn regulate CK1α function. We present evidence that MDMX is a potent competitive inhibitor of CK1α kinase activity (Ki = 8 nM). Depletion of MDMX increases CK1α activity and β-catenin S45 phosphorylation, whereas ectopic MDMX expression inhibits CK1α activity and β-catenin phosphorylation. The MDMX acidic domain and zinc finger are necessary and sufficient for binding and inhibition of CK1α. P53 binding to MDMX disrupts an intramolecular auto-regulatory interaction and enhances its ability to inhibit CK1α. P53-null mice expressing the MDMXW 200S/W201G mutant, defective in CK1α binding, exhibit reduced Wnt/β-catenin target gene expression and delayed tumor development. Therefore, MDMX is a physiological inhibitor of CK1α and has a role in modulating cellular response to Wnt signaling. The MDMX-CK1α interaction may account for certain p53-independent functions of MDMX.
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Affiliation(s)
- Qingling Huang
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, FL, USA
| | - Lihong Chen
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, FL, USA
| | - Ernst Schonbrunn
- Drug Discovery Department, Moffitt Cancer Center, Tampa, FL, USA
| | - Jiandong Chen
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, FL, USA
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Cisplatin Resistance in Testicular Germ Cell Tumors: Current Challenges from Various Perspectives. Cancers (Basel) 2020; 12:cancers12061601. [PMID: 32560427 PMCID: PMC7352163 DOI: 10.3390/cancers12061601] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/13/2020] [Accepted: 06/16/2020] [Indexed: 02/07/2023] Open
Abstract
Testicular germ cell tumors share a marked sensitivity to cisplatin, contributing to their overall good prognosis. However, a subset of patients develop resistance to platinum-based treatments, by still-elusive mechanisms, experiencing poor quality of life due to multiple (often ineffective) interventions and, eventually, dying from disease. Currently, there is a lack of defined treatment opportunities for these patients that tackle the mechanism(s) underlying the emergence of resistance. Herein, we aim to provide a multifaceted overview of cisplatin resistance in testicular germ cell tumors, from the clinical perspective, to the pathobiology (including mechanisms contributing to induction of the resistant phenotype), to experimental models available for studying this occurrence. We provide a systematic summary of pre-target, on-target, post-target, and off-target mechanisms putatively involved in cisplatin resistance, providing data from preclinical studies and from those attempting validation in clinical samples, including those exploring specific alterations as therapeutic targets, some of them included in ongoing clinical trials. We briefly discuss the specificities of resistance related to teratoma (differentiated) phenotype, including the phenomena of growing teratoma syndrome and development of somatic-type malignancy. Cisplatin resistance is most likely multifactorial, and a combination of therapeutic strategies will most likely produce the best clinical benefit.
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Lobo J, Alzamora MA, Guimarães R, Cantante M, Lopes P, Braga I, Maurício J, Jerónimo C, Henrique R. p53 and MDM2 expression in primary and metastatic testicular germ cell tumors: Association with clinical outcome. Andrology 2020; 8:1233-1242. [PMID: 32384200 DOI: 10.1111/andr.12814] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/01/2020] [Accepted: 05/03/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND Testicular germ cell tumors (TGCTs) are highly sensitive to platinum-based chemotherapy, and wild-type p53 seems to play a pivotal role in this susceptibility. On the other hand, overexpression of MDM2 seems to entail treatment resistance and unfavorable prognosis. OBJECTIVES We aimed to describe p53 and MDM2 immunoexpression in a well-characterized cohort of primary and metastatic TGCTs and evaluate associations with clinicopathological and prognostic variables, including survival. MATERIALS AND METHODS 237 primary tumor samples and 12 metastases were evaluated for p53 and MDM2 immunoexpression using digital image analysis. Clinical records of all patients were reviewed for baseline clinical/pathologic characteristics and follow-up. RESULTS A significant positive correlation between p53 and MDM2 H-scores was found (rs = 0.590, P < .0001). Non-seminomas showed significantly higher expression levels of both p53 and MDM2 (P = .0002, P < .0001), which peaked in embryonal carcinomas and choriocarcinomas. Percentage of immunoexpressing cells and H-score were significantly higher in chemo-treated metastases compared with chemo-naïve primary tumors for MDM2 (P ≤ .0001 for both), but not for p53 (P = .919 and P = .703, respectively). Cases with higher MDM2 immunoexpression showed a statistically significant trend for association with poorer prognosis (P = .043). Relapse/progression-free survival at 12 months post-diagnosis was lower in the "MDM2-high" (≥P50) vs. the "MDM2-low" (<P50) expression groups. DISCUSSION AND CONCLUSION In TGCTs, MDM2 overexpression may indicate a more aggressive tumor phenotype, with propensity for therapy resistance and recurrence. If validated in larger multi-institutional studies with precise quantification, it may be envisioned as a useful predictive biomarker of poor response to cisplatin.
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Affiliation(s)
- João Lobo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal.,Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Porto, Portugal.,Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Maria Ana Alzamora
- Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Rita Guimarães
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Mariana Cantante
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Paula Lopes
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Isaac Braga
- Department of Urology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Joaquina Maurício
- Department of Medical Oncology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Porto, Portugal
| | - Rui Henrique
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (GEBC CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto) & Porto Comprehensive Cancer Center (P.CCC), Porto, Portugal.,Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), Porto, Portugal.,Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Porto, Portugal
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de Oliveira Ribeiro H, Cortez AP, de Ávila RI, da Silva ACG, de Carvalho FS, Menegatti R, Lião LM, Valadares MC. Small-molecule MDM2 inhibitor LQFM030-induced apoptosis in p53-null K562 chronic myeloid leukemia cells. Fundam Clin Pharmacol 2020; 34:444-457. [PMID: 32011031 DOI: 10.1111/fcp.12540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 01/01/2023]
Abstract
Our group designed and synthesized the N-phenyl-piperazine LQFM030 [1-(4-((1-(4-chlorophenyl)-1H-pyrazol-4-yl)methyl) piperazin-1-yl) ethanone], a small molecule derived from molecular simplification of the Nutlin-1, an inhibitor of the human homologue of murine double minute 2 (MDM2) protein that is expressed in several types of cancer. To better investigate the effects of LQFM030 regarding the p53 mutation status, this study investigated the antiproliferative activity of LQFM030 against the p53-null K562 leukemia cells as well as the cell death pathways involved. In addition, the effects of LQFM030 on the levels of the p53/MDM2 complex were also carried out using 3T3 cells as a p53 wild-type model. Our data suggest that LQFM030 triggered apoptosis in K562 cells via different mechanisms including cell cycle arrest, caspase activation, reduction of mitochondrial activity, decrease in MDM2 expression, and transcriptional modulation of MDMX, p73, MYC, and NF-ĸB. Additionally, it promoted effects in p53/MDM2 binding in p53 wild-type 3T3 cells. Therefore, LQFM030 has antiproliferative effects in cancer cells by a p53 mutation status-independent manner with different signaling pathways. These findings open new perspectives to the treatment of leukemic cells considering the resistance development associated with cancer treatment with conventional cytotoxic drugs.
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Affiliation(s)
- Higor de Oliveira Ribeiro
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Alane Pereira Cortez
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Renato Ivan de Ávila
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Artur Christian Garcia da Silva
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Flávio Silva de Carvalho
- Laboratório de Química Farmacêutica Medicinal (LQFM), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Ricardo Menegatti
- Laboratório de Química Farmacêutica Medicinal (LQFM), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Luciano Morais Lião
- Laboratório de Ressonância Magnética Nuclear, Instituto de Química, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
| | - Marize Campos Valadares
- Laboratory of Education and Research in In Vitro Toxicology - Tox In, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, 74605-220, Brazil
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11
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Sang P, Shi Y, Lu J, Chen L, Yang L, Borcherds W, Abdulkadir S, Li Q, Daughdrill G, Chen J, Cai J. α-Helix-Mimicking Sulfono-γ-AApeptide Inhibitors for p53-MDM2/MDMX Protein-Protein Interactions. J Med Chem 2020; 63:975-986. [PMID: 31971801 PMCID: PMC7025332 DOI: 10.1021/acs.jmedchem.9b00993] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The use of peptidomimetic scaffolds is a promising strategy for the inhibition of protein-protein interactions (PPIs). Herein, we demonstrate that sulfono-γ-AApeptides can be rationally designed to mimic the p53 α-helix and inhibit p53-MDM2 PPIs. The best inhibitor, with Kd and IC50 values of 26 nM and 0.891 μM toward MDM2, respectively, is among the most potent unnatural peptidomimetic inhibitors disrupting the p53-MDM2/MDMX interaction. Using fluorescence polarization assays, circular dichroism, nuclear magnetic resonance spectroscopy, and computational simulations, we demonstrate that sulfono-γ-AApeptides adopt helical structures resembling p53 and competitively inhibit the p53-MDM2 interaction by binding to the hydrophobic cleft of MDM2. Intriguingly, the stapled sulfono-γ-AApeptides showed promising cellular activity by enhancing p53 transcriptional activity and inducing expression of MDM2 and p21. Moreover, sulfono-γ-AApeptides exhibited remarkable resistance to proteolysis, augmenting their biological potential. Our results suggest that sulfono-γ-AApeptides are a new class of unnatural helical foldamers that disrupt PPIs.
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Affiliation(s)
- Peng Sang
- Department of Chemistry , University of South Florida , 4202 E. Fowler Avenue , Tampa , Florida 33620 , United States
| | - Yan Shi
- Department of Chemistry , University of South Florida , 4202 E. Fowler Avenue , Tampa , Florida 33620 , United States
| | - Junhao Lu
- Department of Molecular Oncology , H. Lee Moffitt Cancer Center and Research Institute , 12902 Magnolia Drive , Tampa , Florida 33612 , United States
| | - Lihong Chen
- Department of Molecular Oncology , H. Lee Moffitt Cancer Center and Research Institute , 12902 Magnolia Drive , Tampa , Florida 33612 , United States
| | - Leixiang Yang
- Department of Molecular Oncology , H. Lee Moffitt Cancer Center and Research Institute , 12902 Magnolia Drive , Tampa , Florida 33612 , United States
| | - Wade Borcherds
- Department of Cell Biology, Microbiology and Molecular Biology , University of South Florida , Tampa , Florida 33620 , United States
| | - Sami Abdulkadir
- Department of Chemistry , University of South Florida , 4202 E. Fowler Avenue , Tampa , Florida 33620 , United States
| | - Qi Li
- Department of Medical Oncology , Shuguang Hospital, Shanghai University of Traditional Chinese Medicine , Shanghai 201203 , China
| | - Gary Daughdrill
- Department of Cell Biology, Microbiology and Molecular Biology , University of South Florida , Tampa , Florida 33620 , United States
| | - Jiandong Chen
- Department of Molecular Oncology , H. Lee Moffitt Cancer Center and Research Institute , 12902 Magnolia Drive , Tampa , Florida 33612 , United States
| | - Jianfeng Cai
- Department of Chemistry , University of South Florida , 4202 E. Fowler Avenue , Tampa , Florida 33620 , United States
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12
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De Giorgi U, Casadei C, Bergamini A, Attademo L, Cormio G, Lorusso D, Pignata S, Mangili G. Therapeutic Challenges for Cisplatin-Resistant Ovarian Germ Cell Tumors. Cancers (Basel) 2019; 11:cancers11101584. [PMID: 31627378 PMCID: PMC6826947 DOI: 10.3390/cancers11101584] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/13/2022] Open
Abstract
The majority of patients with advanced ovarian germ cell cancer are treated by cisplatin-based chemotherapy. Despite adequate first-line treatment, nearly one third of patients relapse and almost half develop cisplatin-resistant disease, which is often fatal. The treatment of cisplatin-resistant disease is challenging and prognosis remains poor. There are limited data on the efficacy of specific chemotherapeutic regimens, high-dose chemotherapy with autologous progenitor cell support and targeted therapies. The inclusion of patients in clinical trials is strongly recommended, especially in clinical trials on the most frequent male germ cell tumors, to offer wider therapeutic opportunities. Here, we provide an overview of current and potential new treatment options including combination chemotherapy, high-dose chemotherapy and molecular targeted therapies, for patients with cisplatin-resistant ovarian germ cell tumors.
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Affiliation(s)
- Ugo De Giorgi
- Department of Medical Oncology and Hematology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Chiara Casadei
- Department of Medical Oncology and Hematology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Alice Bergamini
- Department of Obstetrics and Gynaecology, San Raffaele Scientific Institute, 20132 Milan, Italy.
| | - Laura Attademo
- Department of Urology and Gynecology, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, 80138 Naples, Italy.
| | - Gennaro Cormio
- Gynecologic Oncology Unit, IRCCS Istituto Oncologico Giovanni Paolo II, 70124 Bari, Italy.
| | - Domenica Lorusso
- Gynecologic Oncology Unit, Department of Woman, Child Health and Public Health, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, 00168 Rome, Italy.
| | - Sandro Pignata
- Department of Urology and Gynecology, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, 80138 Naples, Italy.
| | - Giorgia Mangili
- Department of Obstetrics and Gynaecology, San Raffaele Scientific Institute, 20132 Milan, Italy.
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13
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Das MK, Kleppa L, Haugen TB. Functions of genes related to testicular germ cell tumour development. Andrology 2019; 7:527-535. [DOI: 10.1111/andr.12663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/05/2019] [Accepted: 05/12/2019] [Indexed: 12/15/2022]
Affiliation(s)
- M. K. Das
- Faculty of Health Sciences; OsloMet - Oslo Metropolitan University; Oslo Norway
- Department of Molecular Medicine, Faculty of Medicine; University of Oslo; Oslo Norway
| | - L. Kleppa
- Faculty of Health Sciences; OsloMet - Oslo Metropolitan University; Oslo Norway
| | - T. B. Haugen
- Faculty of Health Sciences; OsloMet - Oslo Metropolitan University; Oslo Norway
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14
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Liu Y, Wang X, Wang G, Yang Y, Yuan Y, Ouyang L. The past, present and future of potential small-molecule drugs targeting p53-MDM2/MDMX for cancer therapy. Eur J Med Chem 2019; 176:92-104. [PMID: 31100649 DOI: 10.1016/j.ejmech.2019.05.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 02/05/2023]
Abstract
The p53 gene, a well-known tumor suppressor gene, plays a crucial role in cell cycle regulation, DNA repair, cell differentiation, and apoptosis. MDM2 exerts p53-dependent activity mainly by binding to p53 protein to form MDM2-p53 negative feedback loop. In addition, MDM2 is involved in a number of pathways that regulate cell proliferation and apoptosis, playing a p53-independent role. The p53 binding domain of MDMX bind to p53 transcriptional activation domain, inhibiting the transcriptional activity of p53 on its downstream genes, but does not mediate the degradation of p53. The anti-tumor effect is exerted by inhibiting the interaction between the MDM2/MDMX protein and the p53 protein by a small-molecule or by restoring the activity of the p53 protein. This review describes in the structural features, biological functions and mechanisms of p53-MDM2/MDMX, and summarizes small-molecule targeting p53-MDM2/MDMX.
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Affiliation(s)
- Yao Liu
- State Key Laboratory of Biotherapy and Cancer Center, Department of Thoracic Surgery, West China Hospital, Sichuan University, China
| | - Xiaohui Wang
- Department of Pharmacy, Naval Authorities Clinic, Beijing, 100841, China
| | - Guan Wang
- State Key Laboratory of Biotherapy and Cancer Center, Department of Thoracic Surgery, West China Hospital, Sichuan University, China
| | - Yushang Yang
- State Key Laboratory of Biotherapy and Cancer Center, Department of Thoracic Surgery, West China Hospital, Sichuan University, China
| | - Yong Yuan
- State Key Laboratory of Biotherapy and Cancer Center, Department of Thoracic Surgery, West China Hospital, Sichuan University, China.
| | - Liang Ouyang
- State Key Laboratory of Biotherapy and Cancer Center, Department of Thoracic Surgery, West China Hospital, Sichuan University, China.
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15
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Schmidtova S, Kalavska K, Kucerova L. Molecular Mechanisms of Cisplatin Chemoresistance and Its Circumventing in Testicular Germ Cell Tumors. Curr Oncol Rep 2018; 20:88. [PMID: 30259297 DOI: 10.1007/s11912-018-0730-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Testicular germ cell tumors (TGCTs) represent the most common solid tumors affecting young men. Majority of TGCTs respond well to cisplatin-based chemotherapy. However, patients with refractory disease have limited treatment modalities associated with poor prognosis. Here, we discuss the main molecular mechanisms associated with acquired cisplatin resistance in TGCTs and how their understanding might help in the development of new approaches to tackle this clinically relevant problem. We also discuss recent data on the strategies of circumventing the cisplatin resistance from different tumor types potentially efficient also in TGCTs. RECENT FINDINGS Recent data regarding deregulation of various signaling pathways as well as genetic and epigenetic mechanisms in cisplatin-resistant TGCTs have contributed to understanding of the mechanisms related to the resistance to cisplatin-based chemotherapy in these tumors. Understanding of these mechanisms enabled explaining why majority but not all TGCTs patients are curable with cisplatin-based chemotherapy. Moreover, it could lead to the development of more effective treatment of refractory TGCTs and potentially other solid tumors resistant to platinum-based chemotherapy. This review provides additional insights into mechanisms associated with cisplatin resistance in TGCTs, which is a complex phenomenon, and there is a need for novel modalities to overcome it.
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Affiliation(s)
- Silvia Schmidtova
- Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05, Bratislava, Slovakia
| | - Katarina Kalavska
- Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05, Bratislava, Slovakia
- 2nd Department of Oncology, Faculty of Medicine, Comenius University and National Cancer Institute, Klenová 1, 833 10, Bratislava, Slovakia
- Translational Research Unit, Faculty of Medicine, Comenius University, Klenová 1, Bratislava, 833 10, Slovakia
| | - Lucia Kucerova
- Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05, Bratislava, Slovakia.
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16
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Romano FJ, Rossetti S, Conteduca V, Schepisi G, Cavaliere C, Di Franco R, La Mantia E, Castaldo L, Nocerino F, Ametrano G, Cappuccio F, Malzone G, Montanari M, Vanacore D, Quagliariello V, Piscitelli R, Pepe MF, Berretta M, D'Aniello C, Perdonà S, Muto P, Botti G, Ciliberto G, Veneziani BM, De Falco F, Maiolino P, Caraglia M, Montella M, De Giorgi U, Facchini G. Role of DNA repair machinery and p53 in the testicular germ cell cancer: a review. Oncotarget 2018; 7:85641-85649. [PMID: 27821802 PMCID: PMC5356765 DOI: 10.18632/oncotarget.13063] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/19/2016] [Indexed: 12/21/2022] Open
Abstract
Notwithstanding the peculiar sensitivity to cisplatin-based treatment, resulting in a very high percentage of cures even in advanced stages of the disease, still we do not know the biological mechanisms that make Testicular Germ Cell Tumor (TGCT) “unique” in the oncology scene. p53 and MDM2 seem to play a pivotal role, according to several in vitro observations, but no correlation has been found between their mutational or expression status in tissue samples and patients clinical outcome. Furthermore, other players seem to be on stage: DNA Damage Repair Machinery (DDR) , especially Homologous Recombination (HR) proteins, above all Ataxia Telangiectasia Mutated (ATM), cooperates with p53 in response to DNA damage, activating apoptotic cascade and contributing to cell “fate”. Homologous Recombination deficiency has been assumed to be a Germ Cell Tumor characteristic underlying platinum-sensitivity, whereby Poly(ADP-ribose) polymerase (PARP), an enzyme involved in HR DNA repair, is an intriguing target: PARP inhibitors have already entered in clinical practice of other malignancies and trials are recruiting TGCT patients in order to validate their role in this disease. This paper aims to summarize evidence, trying to outline an overview of DDR implications not only in TGCT curability, but also in resistance to chemotherapy.
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Affiliation(s)
- Francesco Jacopo Romano
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy
| | - Sabrina Rossetti
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori 'Fondazione G. Pascale', IRCCS, Naples, Italy
| | - Vincenza Conteduca
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRCCS, Meldola, Italy
| | - Giuseppe Schepisi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRCCS, Meldola, Italy
| | - Carla Cavaliere
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Department of Onco-Ematology Medical Oncology, S.G. Moscati Hospital of Taranto, Taranto, Italy
| | - Rossella Di Franco
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Radiation Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Elvira La Mantia
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Pathology Unit, Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy
| | - Luigi Castaldo
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Department of Uro-Gynaecological Oncology, Division of Urology, Istituto Nazionale Tumori 'Fondazione G. Pascale', IRCCS, Naples, Italy
| | - Flavia Nocerino
- Epidemiology Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Gianluca Ametrano
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Radiation Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Francesca Cappuccio
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Psicology Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Gabriella Malzone
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Pathology Unit, Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy
| | - Micaela Montanari
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Naples, Italy
| | - Daniela Vanacore
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy
| | - Vincenzo Quagliariello
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy
| | - Raffaele Piscitelli
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Pharmacy Unit, Istituto Nazionale Tumori, Istituto Nazionale Tumori-Fondazione G. Pascale Naples, Italy
| | - Maria Filomena Pepe
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Pathology Unit, Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy
| | - Massimiliano Berretta
- Department of Medical Oncology, CRO Aviano, National Cancer Institute, Aviano, Italy
| | - Carmine D'Aniello
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Division of Medical Oncology, A.O.R.N. dei COLLI "Ospedali Monaldi-Cotugno-CTO", Napoli, Italy
| | - Sisto Perdonà
- Department of Uro-Gynaecological Oncology, Division of Urology, Istituto Nazionale Tumori 'Fondazione G. Pascale', IRCCS, Naples, Italy
| | - Paolo Muto
- Radiation Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Gerardo Botti
- Pathology Unit, Istituto Nazionale Tumori "Fondazione G. Pascale"-IRCCS, Naples, Italy
| | - Gennaro Ciliberto
- Scientific Directorate, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Bianca Maria Veneziani
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Naples, Italy
| | - Francesco De Falco
- Psicology Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Piera Maiolino
- Pharmacy Unit, Istituto Nazionale Tumori, Istituto Nazionale Tumori-Fondazione G. Pascale Naples, Italy
| | - Michele Caraglia
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Maurizio Montella
- Epidemiology Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori 'Fondazione Giovanni Pascale', IRCCS, Napoli, Italy
| | - Ugo De Giorgi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRCCS, Meldola, Italy
| | - Gaetano Facchini
- Progetto ONCONET2.0, Linea Progettuale 14 per L'implementazione della Prevenzione e Diagnosi Precoce del Tumore alla Prostata e Testicolo, Regione Campania, Italy.,Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori 'Fondazione G. Pascale', IRCCS, Naples, Italy
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17
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Optimal Affinity Enhancement by a Conserved Flexible Linker Controls p53 Mimicry in MdmX. Biophys J 2017; 112:2038-2042. [PMID: 28487147 DOI: 10.1016/j.bpj.2017.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/29/2017] [Accepted: 04/17/2017] [Indexed: 01/10/2023] Open
Abstract
MdmX contains an intramolecular binding motif that mimics the binding of the p53 tumor suppressor. This intramolecular binding motif is connected to the p53 binding domain of MdmX by a conserved flexible linker that is 85 residues long. The sequence of this flexible linker has an identity of 51% based on multiple protein sequence alignments of 52 MdmX homologs. We used polymer statistics to estimate a global KD value for p53 binding to MdmX in the presence of the flexible linker and the intramolecular binding motif by assuming the flexible linker behaves as a wormlike chain. The global KD estimated from the wormlike chain modeling was nearly identical to the value measured using isothermal titration calorimetry. According to our calculations and measurements, the intramolecular binding motif reduces the apparent affinity of p53 for MdmX by a factor of 400. This study promotes a more quantitative understanding of the role that flexible linkers play in intramolecular binding and provides valuable information to further studies of cellular inhibition of the p53/MdmX interaction.
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18
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Zhou X, Cao B, Lu H. Negative auto-regulators trap p53 in their web. J Mol Cell Biol 2017; 9:62-68. [PMID: 28069666 PMCID: PMC5907828 DOI: 10.1093/jmcb/mjx001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/14/2016] [Accepted: 01/06/2017] [Indexed: 01/07/2023] Open
Abstract
The transcriptional factor p53 activates the expression of a myriad of target genes involving a complicated signalling network, resulting in various cellular outcomes, such as growth arrest, senescence, apoptosis, and metabolic changes, and leading to consequent suppression of tumour growth and progression. Because of the profoundly adverse effect of p53 on growth and proliferation of cancer cells, several feedback mechanisms have been employed by the cells to constrain p53 activity. Two major antagonists MDM2 and MDMX (the long forms) are transcriptionally induced by p53, but in return block p53 activity, forming a negative feedback circuit and rendering chemoresistance of several cancer cells. However, they are not alone, as cancer cells also employ other proteins encoded by p53 target genes to inhibit p53 activity at transcriptional, translational, and posttranslational levels. This essay is thus composed to review a recent progress in understanding the mechanisms for how cancer cells hijack the p53 autoregulation by these proteins for their growth advantage and to discuss the clinical implications of these autoregulatory loops.
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Affiliation(s)
- Xiang Zhou
- Fudan University Shanghai Cancer Center and the Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Bo Cao
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
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19
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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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20
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The genomic landscape of testicular germ cell tumours: from susceptibility to treatment. Nat Rev Urol 2016; 13:409-19. [PMID: 27296647 DOI: 10.1038/nrurol.2016.107] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The genomic landscape of testicular germ cell tumour (TGCT) can be summarized using four overarching hypotheses. Firstly, TGCT risk is dominated by inherited genetic factors, which determine nearly half of all disease risk and are highly polygenic in nature. Secondly KIT-KITLG signalling is currently the major pathway that is implicated in TGCT formation, both as a predisposition risk factor and a somatic driver event. Results from genome-wide association studies have also consistently suggested that other closely related pathways involved in male germ cell development and sex determination are associated with TGCT risk. Thirdly, the method of disease formation is unique, with tumours universally stemming from a noninvasive precursor lesion, probably of fetal origin, which lies dormant through childhood into adolescence and then eventually begins malignant growth in early adulthood. Formation of a 12p isochromosome, a hallmark of TGCT observed in nearly all tumours, is likely to be a key triggering event for malignant transformation. Finally, TGCT have been shown to have a distinctive somatic mutational profile, with a low rate of point mutations contrasted with frequent large-scale chromosomal gains. These four hypotheses by no means constitute a complete model that explains TGCT tumorigenesis, but advances in genomic technologies have enabled considerable progress in describing and understanding the disease. Further advancing our understanding of the genomic basis of TGCT offers a clear opportunity for clinical benefit in terms of preventing invasive cancer arising in young men, decreasing the burden of chemotherapy-related survivorship issues and reducing mortality in the minority of patients who have treatment-refractory disease.
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21
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Oing C, Kollmannsberger C, Oechsle K, Bokemeyer C. Investigational targeted therapies for the treatment of testicular germ cell tumors. Expert Opin Investig Drugs 2016; 25:1033-43. [PMID: 27286362 DOI: 10.1080/13543784.2016.1195808] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Germ cell tumors (GCTs) are the most common malignancy among men aged between 15 to 45. Despite high cure rates of >90% over all GCTs, 3 to 5% of patients will still die of platinum-refractory disease. New systemic treatment options are needed to improve treatment success in this challenging setting. AREAS COVERED To review targeted treatment options and preclinical developments in platinum-refractory GCTs, a comprehensive literature search of PubMed, Medline and scientific meeting abstracts on published clinical trials and reports on molecularly targeted approaches was conducted. Outcomes of platinum-refractory disease and of patients failing high-dose chemotherapy remain poor. Currently, no molecularly targeted treatment has shown clinically meaningful activity in unselected patient populations in clinical trials, but individual patients may achieve short-lived objective responses by treatment with sunitinib, brentuximab vedotin or imatinib. Targeted trials based on molecular selection of patients have not yet been performed. EXPERT OPINION The limited activity of targeted agents in refractory GCT is disappointing. Assessment of druggable biomarkers and marker-stratified treatment may help individual patients, but is largely lacking. The low incidence and high curability of GCTs make the design of larger clinical trials difficult. The potential of novel agents, i.e. immune-checkpoint inhibitors, remains to be elucidated.
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Affiliation(s)
- Christoph Oing
- a Department of Oncology, Hematology and Bone Marrow Transplantation , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Christian Kollmannsberger
- b Division of Medical Oncology, British Columbia Cancer Agency Vancouver Cancer Center , University of British Columbia , Vancouver , Canada
| | - Karin Oechsle
- a Department of Oncology, Hematology and Bone Marrow Transplantation , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Carsten Bokemeyer
- a Department of Oncology, Hematology and Bone Marrow Transplantation , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
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22
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Boublikova L, Bakardjieva-Mihaylova V, Skvarova Kramarzova K, Kuzilkova D, Dobiasova A, Fiser K, Stuchly J, Kotrova M, Buchler T, Dusek P, Grega M, Rosova B, Vernerova Z, Klezl P, Pesl M, Zachoval R, Krolupper M, Kubecova M, Stahalova V, Abrahamova J, Babjuk M, Kodet R, Trka J. Wilms tumor gene 1 (WT1), TP53, RAS/BRAF and KIT aberrations in testicular germ cell tumors. Cancer Lett 2016; 376:367-76. [PMID: 27085458 DOI: 10.1016/j.canlet.2016.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/04/2016] [Accepted: 04/08/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE Wilms tumor gene 1 (WT1), a zinc-finger transcription factor essential for testis development and function, along with other genes, was investigated for their role in the pathogenesis of testicular germ cell tumors (TGCT). METHODS In total, 284 TGCT and 100 control samples were investigated, including qPCR for WT1 expression and BRAF mutation, p53 immunohistochemistry detection, and massively parallel amplicon sequencing. RESULTS WT1 was significantly (p < 0.0001) under-expressed in TGCT, with an increased ratio of exon 5-lacking isoforms, reaching low levels in chemo-naïve relapsed TGCT patients vs. high levels in chemotherapy-pretreated relapsed patients. BRAF V600E mutation was identified in 1% of patients only. p53 protein was lowly expressed in TGCT metastases compared to the matched primary tumors. Of 9 selected TGCT-linked genes, RAS/BRAF and WT1 mutations were frequent while significant TP53 and KIT variants were not detected (p = 0.0003). CONCLUSIONS WT1 has been identified as a novel factor involved in TGCT pathogenesis, with a potential prognostic impact. Distinct biologic nature of the two types of relapses occurring in TGCT has been demonstrated. Differential mutation rate of the key TGCT-related genes has been documented.
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Affiliation(s)
- L Boublikova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic.
| | - V Bakardjieva-Mihaylova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - K Skvarova Kramarzova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - D Kuzilkova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - A Dobiasova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - K Fiser
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - J Stuchly
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - M Kotrova
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - T Buchler
- Department of Oncology, 1st Faculty of Medicine, Charles University and Thomayer Hospital, Prague, Czech Republic
| | - P Dusek
- Department of Urology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - M Grega
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - B Rosova
- Department of Pathology and Molecular Medicine, Thomayer Hospital, Prague, Czech Republic
| | - Z Vernerova
- Department of Pathology, 3rd Faculty of Medicine, Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - P Klezl
- Department of Urology, 3rd Faculty of Medicine, Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - M Pesl
- Department of Urology, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - R Zachoval
- Department of Urology, Thomayer Hospital, Prague, Czech Republic
| | - M Krolupper
- Department of Urology, Na Bulovce Hospital, Prague, Czech Republic
| | - M Kubecova
- Department of Oncology and Radiotherapy, 3rd Faculty of Medicine, Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - V Stahalova
- Institute of Radiotherapy and Oncology, 1st Faculty of Medicine, Charles University and Na Bulovce Hospital, Prague, Czech Republic
| | - J Abrahamova
- Department of Oncology, 1st Faculty of Medicine, Charles University and Thomayer Hospital, Prague, Czech Republic
| | - M Babjuk
- Department of Urology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - R Kodet
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - J Trka
- Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
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23
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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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Abstract
The p53 inhibitor MDMX is controlled by multiple stress signaling pathways. Using a proteolytic fragment release (PFR) assay, we detected an intramolecular interaction in MDMX that mechanistically mimics the interaction with p53, resulting in autoinhibition of MDMX. This mimicry is mediated by a hydrophobic peptide located in a long disordered central segment of MDMX that has sequence similarity to the p53 transactivation domain. NMR spectroscopy was used to show this hydrophobic peptide interacts with the N-terminal domain of MDMX in a structurally analogous manner to p53. Mutation of two critical tryptophan residues in the hydrophobic peptide disrupted the intramolecular interaction and increased p53 binding, providing further evidence for mechanistic mimicry. The PFR assay also revealed a second intramolecular interaction between the RING domain and central region that regulates MDMX nuclear import. These results establish the importance of intramolecular interactions in MDMX regulation, and validate a new assay for the study of intramolecular interactions in multidomain proteins with intrinsically disordered regions.
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25
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Chong KH, Samarasinghe S, Kulasiri D. Mathematical modelling of p53 basal dynamics and DNA damage response. Math Biosci 2015; 259:27-42. [DOI: 10.1016/j.mbs.2014.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 10/23/2014] [Accepted: 10/31/2014] [Indexed: 02/06/2023]
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26
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The chemosensitivity of testicular germ cell tumors. Cell Oncol (Dordr) 2014; 37:79-94. [PMID: 24692098 DOI: 10.1007/s13402-014-0168-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2014] [Indexed: 12/13/2022] Open
Abstract
Although rare cancers overall, testicular germ cell tumors (TGCTs) are the most common type of cancer in young males below 40 years of age. Both subtypes of TGCTs, i.e., seminomas and non-seminomas, are highly curable and the majority of even metastatic patients may expect to be cured. These high cure rates are not due to the indolent nature of these cancers, but rather to their sensitivity to chemotherapy (and for seminomas to radiotherapy). The delineation of the cause of chemosensitivity at the molecular level is of paramount importance, because it may provide insights into the minority of TGCTs that are chemo-resistant and, thereby, provide opportunities for specific therapeutic interventions aimed at reverting them to chemosensitivity. In addition, delineation of the molecular basis of TGCT chemo-sensitivity may be informative for the cause of chemo-resistance of other more common types of cancer and, thus, may create new therapeutic leads. p53, a frequently mutated tumor suppressor in cancers in general, is not mutated in TGCTs, a fact that has implications for their chemo-sensitivity. Oct4, an embryonic transcription factor, is uniformly expressed in the seminoma and embryonic carcinoma components of non-seminomas, and its interplay with p53 may be important in the chemotherapy response of these tumors. This interplay, together with other features of TGCTs such as the gain of genetic material from the short arm of chromosome 12 and the association with disorders of testicular development, will be discussed in this paper and integrated in a unifying hypothesis that may explain their chemo-sensitivity.
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27
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Boublikova L, Buchler T, Stary J, Abrahamova J, Trka J. Molecular biology of testicular germ cell tumors: Unique features awaiting clinical application. Crit Rev Oncol Hematol 2014; 89:366-85. [DOI: 10.1016/j.critrevonc.2013.10.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/30/2013] [Accepted: 10/01/2013] [Indexed: 01/29/2023] Open
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28
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Hock AK, Vousden KH. The role of ubiquitin modification in the regulation of p53. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:137-49. [DOI: 10.1016/j.bbamcr.2013.05.022] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/16/2013] [Accepted: 05/23/2013] [Indexed: 01/09/2023]
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29
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Van Maerken T, Rihani A, Van Goethem A, De Paepe A, Speleman F, Vandesompele J. Pharmacologic activation of wild-type p53 by nutlin therapy in childhood cancer. Cancer Lett 2013; 344:157-65. [PMID: 24262662 DOI: 10.1016/j.canlet.2013.11.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/20/2013] [Accepted: 11/10/2013] [Indexed: 02/08/2023]
Abstract
A peculiar feature of several types of childhood cancer is that loss-of-function mutations of the TP53 (p53) tumor suppressor gene are uncommon, in contrast to many adult tumors. As p53 needs to be inactivated in order for tumor cells to survive and thrive, pediatric tumors typically make use of other mechanisms to keep p53 in check. One of the critical negative regulators of p53 is the MDM2 oncoprotein. Many anticancer drug development efforts in the past decade have therefore been devoted to the discovery and optimization of small molecules that selectively disrupt the interaction between MDM2 and p53, which could provide, in principle, a potent means to restore p53 function in tumor cells with wild-type p53. The nutlins are the class of selective inhibitors of the p53-MDM2 interaction that are currently most advanced in their clinical development. We review here the preclinical data that support the potential therapeutic use of nutlin drugs in the treatment of various pediatric tumors, including neuroblastoma, retinoblastoma, osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, medulloblastoma, and childhood acute lymphoblastic leukemia.
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Affiliation(s)
- Tom Van Maerken
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.
| | - Ali Rihani
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Alan Van Goethem
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Anne De Paepe
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Frank Speleman
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Jo Vandesompele
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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30
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Unravelling mechanisms of cisplatin sensitivity and resistance in testicular cancer. Expert Rev Mol Med 2013; 15:e12. [PMID: 24074238 DOI: 10.1017/erm.2013.13] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Testicular cancer is the most frequent solid malignant tumour type in men 20-40 years of age. At the time of diagnosis up to 50% of the patients suffer from metastatic disease. In contrast to most other metastatic solid tumours, the majority of metastatic testicular cancer patients can be cured with highly effective cisplatin-based chemotherapy. This review aims to summarise the current knowledge on response to chemotherapy and the biological basis of cisplatin-induced apoptosis in testicular cancer. The frequent presence of wild-type TP53 and the low levels of p53 in complex with the p53 negative feed-back regulator MDM2 contribute to cisplatin sensitivity. Moreover, the high levels of the pluripotency regulator Oct4 and as a consequence of Oct4 expression high levels of miR-17/106b seed family and pro-apoptotic Noxa and the low levels of cytoplasmic p21 (WAF1/Cip1) appear to be causative for the exquisite sensitivity to cisplatin-based therapy of testicular cancer. However, resistance of testicular cancer to cisplatin-based therapy does occur and can be mediated through aberrant levels of the above mentioned key players. Drugs targeting these key players showed, at least pre-clinically, a sensitising effect to cisplatin treatment. Further clinical development of such treatment strategies will lead to new treatment options for platinum-resistant testicular cancers.
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31
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McCubrey JA, Demidenko ZN. Recent discoveries in the cycling, growing and aging of the p53 field. Aging (Albany NY) 2013; 4:887-93. [PMID: 23425920 PMCID: PMC3615156 DOI: 10.18632/aging.100529] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The P53 gene and it product p53 protein is the most studied tumor suppressor, which was considered as oncogene for two decades until 1990. More than 60 thousand papers on the topic of p53 has been abstracted in Pubmed. What yet could be discovered about its role in cell death, growth arrest and apoptosis, as well as a mediator of the therapeutic effect of anticancer drugs. Still during recent few years even more amazing discoveries have been done. Here we review such topics as suppression of epigenetic silencing of a large number of non-coding RNAs, role of p53 in suppression of the senescence phenotype, inhibition of oncogenic metabolism, protection of normal cells from chemotherapy and even tumor suppression without apoptosis and cell cycle arrest.
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Affiliation(s)
- James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, NC 27858, USA.
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32
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Kenzelmann Broz D, Spano Mello S, Bieging KT, Jiang D, Dusek RL, Brady CA, Sidow A, Attardi LD. Global genomic profiling reveals an extensive p53-regulated autophagy program contributing to key p53 responses. Genes Dev 2013; 27:1016-31. [PMID: 23651856 DOI: 10.1101/gad.212282.112] [Citation(s) in RCA: 321] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mechanisms by which the p53 tumor suppressor acts remain incompletely understood. To gain new insights into p53 biology, we used high-throughput sequencing to analyze global p53 transcriptional networks in primary mouse embryo fibroblasts in response to DNA damage. Chromatin immunoprecipitation sequencing reveals 4785 p53-bound sites in the genome located near 3193 genes involved in diverse biological processes. RNA sequencing analysis shows that only a subset of p53-bound genes is transcriptionally regulated, yielding a list of 432 p53-bound and regulated genes. Interestingly, we identify a host of autophagy genes as direct p53 target genes. While the autophagy program is regulated predominantly by p53, the p53 family members p63 and p73 contribute to activation of this autophagy gene network. Induction of autophagy genes in response to p53 activation is associated with enhanced autophagy in diverse settings and depends on p53 transcriptional activity. While p53-induced autophagy does not affect cell cycle arrest in response to DNA damage, it is important for both robust p53-dependent apoptosis triggered by DNA damage and transformation suppression by p53. Together, our data highlight an intimate connection between p53 and autophagy through a vast transcriptional network and indicate that autophagy contributes to p53-dependent apoptosis and cancer suppression.
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Affiliation(s)
- Daniela Kenzelmann Broz
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305, USA
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33
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Lui K, An J, Montalbano J, Shi J, Corcoran C, He Q, Sun H, Sheikh MS, Huang Y. Negative regulation of p53 by Ras superfamily protein RBEL1A. J Cell Sci 2013; 126:2436-45. [PMID: 23572512 DOI: 10.1242/jcs.118117] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We had previously reported that RBEL1A, a novel Ras-like GTPase, was overexpressed in multiple human malignancies and that its depletion suppressed cell growth. However, the underlying molecular mechanism remained to be elucidated. Here we report that depletion of endogenous RBEL1A results in p53 accumulation due to increased p53 half-life whereas increased expression of RBEL1A reduces p53 levels under unstressed and genotoxic stress conditions. RBEL1A directly interacts with p53 and MDM2, and strongly enhances MDM2-dependent p53 ubiquitylation and degradation. We also found that RBEL1A modulation of p53 ubiquitylation by MDM2 does not depend on its GTPase activity. We have also defined the p53 oligomeric domain and RBEL1A GTPase domain to be the crucial regions for p53-RBEL1A interactions. Importantly, we have found that RBEL1A strongly interferes with p53 transactivation function; thus our results indicate that RBEL1A appears to function as a novel p53 negative regulator that facilitates MDM2-dependent p53 ubiquitylation and degradation.
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Affiliation(s)
- Ki Lui
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, New York 13210, USA
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34
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Matin RN, Chikh A, Chong SLP, Mesher D, Graf M, Sanza' P, Senatore V, Scatolini M, Moretti F, Leigh IM, Proby CM, Costanzo A, Chiorino G, Cerio R, Harwood CA, Bergamaschi D. p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis. ACTA ACUST UNITED AC 2013; 210:581-603. [PMID: 23420876 PMCID: PMC3600906 DOI: 10.1084/jem.20121439] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
p63 is up-regulated in melanoma and prevents nuclear accumulation of p53. The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents.
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Affiliation(s)
- Rubeta N Matin
- Centre for Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, England, UK
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35
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Gutekunst M, Mueller T, Weilbacher A, Dengler MA, Bedke J, Kruck S, Oren M, Aulitzky WE, van der Kuip H. Cisplatin Hypersensitivity of Testicular Germ Cell Tumors Is Determined by High Constitutive Noxa Levels Mediated by Oct-4. Cancer Res 2013; 73:1460-9. [DOI: 10.1158/0008-5472.can-12-2876] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Abstract
As published recently in Cancer Cell, p53 impairs the apoptotic response to chemotherapy and clinical outcome in breast cancer. I discuss that, while treating tumors lacking wt p53, this phenomenon can be exploited to protect normal cells from chemotherapy because all normal cells have wt p53. Also, several therapeutic paradigms can be reassessed, including the role of cellular senescence in cancer therapy.
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37
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di Pietro A, Koster R, Boersma-van Eck W, Dam WA, Mulder NH, Gietema JA, de Vries EGE, de Jong S. Pro- and anti-apoptotic effects of p53 in cisplatin-treated human testicular cancer are cell context-dependent. Cell Cycle 2012; 11:4552-62. [PMID: 23165211 DOI: 10.4161/cc.22803] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In murine testicular cancer (TC) cells wild-type p53 contributes to sensitivity to DNA-damaging drugs in a dose-dependent way. In human TC, however, the role of wild-type p53 functionality in chemotherapeutic response remains elusive. We analyzed functionality of wild-type p53 in cisplatin sensitivity in the human TC setting using a p53 short interfering (si)RNA approach. The cisplatin-sensitive TC cell line (Tera), the subline with acquired cisplatin resistance (Tera-CP) and a panel of intrinsically resistant TC cell lines (Scha and 2102EP), all expressing wild-type p53, were used. p53 and p53 transcriptional targets MDM2 and p21 (Waf1/Cip1) (p21) were expressed in a p53 transactivation-dependent way in all TC cell lines. Following cisplatin exposure, expression levels of p53 increased, with a subsequent increase in MDM2 and p21 mRNA and protein levels and Fas cell membrane levels. Downregulation of p53 with siRNA lowered cisplatin-induced apoptosis in Tera and Tera-CP, which was associated with a diminished Fas membrane expression. In contrast, p53 suppression augmented cisplatin-induced apoptosis in Scha and 2102EP and concomitantly strongly suppressed MDM2 and p21 mRNA and protein expression. Our results indicate that p53 is involved in transactivation of pro- and anti-apoptotic genes in untreated and cisplatin-treated TC cells, but subtle differences are present between TC cell lines. The opposite role of p53 in cisplatin-induced apoptosis among TC cell lines demonstrates the importance of the cellular context for the p53 transactivation phenotype in TC cells.
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Affiliation(s)
- Alessandra di Pietro
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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38
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Chen J. The Roles of MDM2 and MDMX Phosphorylation in Stress Signaling to p53. Genes Cancer 2012; 3:274-82. [PMID: 23150760 DOI: 10.1177/1947601912454733] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The p53 tumor suppressor is highly responsive to different physiological stresses such as abnormal cell proliferation, nutrient deprivation, and DNA damage. Distinct signaling mechanisms have evolved to activate p53, which in turn modulate numerous pathways to enhance fitness and survival of the organism. Elucidating the molecular mechanisms of these signaling events is critical for understanding tumor suppression by p53 and development of novel therapeutics. Studies in the past decade have established that MDM2 and MDMX are important targets of signaling input from different pathways. Here, we focus our discussion on MDM2 and MDMX phosphorylation, which is important for p53 activation by DNA damage. Investigations in this area have generated new insight into the inner workings of MDM2 and MDMX and underscore the importance of allosteric communication between different domains in achieving an efficient response to phosphorylation. It is likely that MDM2 and MDMX regulation by phosphorylation will share mechanistic similarities to other signaling hub molecules. Phosphorylation-independent p53 activators such as ARF and ribosomal proteins ultimately achieve the same outcome as phosphorylation, suggesting that they may induce similar changes in the structure and function of MDM2 and MDMX through protein-protein interactions.
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Affiliation(s)
- Jiandong Chen
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, FL, USA
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39
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Ohnstad HO, Castro R, Sun J, Heintz KM, Vassilev LT, Bjerkehagen B, Kresse SH, Meza-Zepeda LA, Myklebost O. Correlation of TP53 and MDM2 genotypes with response to therapy in sarcoma. Cancer 2012; 119:1013-22. [PMID: 23165797 DOI: 10.1002/cncr.27837] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 08/13/2012] [Accepted: 09/04/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Relatively few sarcomas harbor TP53 (tumor protein p53) mutations, but in many cases, amplification of MDM2 (murine double minute 2) effectively inactivate p53. The p53 pathway activity can also be affected by normal genetic variation. METHODS The mutation status of TP53 and expression of MDM2, TP53, and their genetic variants SNP309 and R72P (Arg72Pro) were investigated in 125 sarcoma patient samples and 18 sarcoma cell lines. Association of the different genotypes and gene aberrations with chemotherapy response and survival, as well as response to MDM2 antagonists in vitro was evaluated. RESULTS Twenty-two percent of the tumors had mutant TP53 and 20% MDM2 gene amplification. Patients with wild-type TP53 (TP53(Wt) ) tumors had improved survival (P < .001) and TP53(Wt) was an independent prognostic factor (hazard ratio = 0.41; 95% confidence interval = 0.23-0.74; P = .03). Interestingly, there was a trend toward longer time to progression after chemotherapy for tumors with the apoptosis-prone p53 variant R72 (P = .07), which was strongest with doxorubicin/ifosfamide-based regimens (P = .01). Liposarcomas had low R72 frequency (33% versus 56%), but increased levels of MDM2 and MDM4 (51% and 11%, P < .001). MDM2 overexpression on a TP53(Wt) background predicted better response to MDM2 antagonist Nutlin-3a, irrespective of R72P or SNP309 status. CONCLUSIONS Improved survival after chemotherapy was found in patients with TP53(Wt) tumors harboring the R72 variant. MDM2 overexpression in TP53(Wt) tumors predicted good response to MDM2 antagonists, irrespective of R72P or SNP309 status. Thus, detailed TP53 and MDM2 genotype analyses prior to systemic therapy are recommended.
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Affiliation(s)
- Hege O Ohnstad
- Department of Tumor Biology, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway
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40
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Casein kinase 1α regulates an MDMX intramolecular interaction to stimulate p53 binding. Mol Cell Biol 2012; 32:4821-32. [PMID: 23028042 DOI: 10.1128/mcb.00851-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MDMX is an important regulator of p53 during embryonic development and malignant transformation. Previous studies showed that casein kinase 1α (CK1α) stably associates with MDMX, stimulates MDMX-p53 binding, and cooperates with MDMX to inactivate p53. However, the mechanism by which CK1α stimulates MDMX-p53 interaction remains unknown. Here, we present evidence that p53 binding by the MDMX N-terminal domain is inhibited by the central acidic region through an intramolecular interaction that competes for the p53 binding pocket. CK1α binding to the MDMX central domain and phosphorylation of S289 disrupts the intramolecular interaction, allowing the N terminus to bind p53 with increased affinity. After DNA damage, the MDMX-CK1α complex is disrupted by Chk2-mediated phosphorylation of MDMX at S367, leading to reduced MDMX-p53 binding. Therefore, CK1α is an important functional partner of MDMX. DNA damage activates p53 in part by disrupting CK1α-MDMX interaction and reducing MDMX-p53 binding affinity.
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41
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Abstract
p53 plays an important role in the regulation of the cell cycle, DNA repair, and apoptosis and is an attractive cancer therapeutic target. Mdm2 and Mdmx are recognized as the main p53 negative regulators. Although it is still unknown why Mdm2 and Mdmx both are required for p53 degradation, a model has been proposed whereby these two proteins function independent of one another; Mdm2 acts as an E3 ubiquitin ligase that catalyzes the ubiquitination of p53 for degradation, whereas Mdmx inhibits p53 by binding to and masking the transcriptional activation domain of p53, without causing its degradation. However, Mdm2 and Mdmx have been shown to function collaboratively. In fact, recent studies have pointed to a more important role for an Mdm2/Mdmx co-regulatory mechanism for p53 regulation than previously thought. In this review, we summarize current progress in the field about the functional and physical interactions between Mdm2 and Mdmx, their individual and collaborative roles in controlling p53, and inhibitors that target Mdm2 and Mdmx as a novel class of anticancer therapeutics.
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Affiliation(s)
- Dongsheng Pei
- Laboratory of Biological Cancer Therapy, Xuzhou Medical College, Xuzhou, China
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42
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Abstract
National Cancer Institute has announced 24 provocative questions on cancer. Here I try to answer some of them by linking the dots of existing knowledge.
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Affiliation(s)
- Mikhail V Blagosklonny
- Department of Cell Stress Biology, Roswell Park Cancer Institute, BLSC, L3-312, Elm and Carlton Streets, Buffalo, NY 14263, USA.
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43
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Mdm2 and MdmX partner to regulate p53. FEBS Lett 2012; 586:1390-6. [PMID: 22673503 DOI: 10.1016/j.febslet.2012.02.049] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 02/06/2023]
Abstract
Mdm2 regulates the stability, translation, subcellular localization and transcriptional activity of p53 protein. Mdm2-dependent p53 inhibition is essential in regulating p53 activity during embryonic development and in adult tissues. MdmX, an Mdm2 homolog, is also essential for p53 inhibition in vivo. Recent advances in the field from biochemical and genetic studies have revealed an essential role for the MdmX RING domain in Mdm2-dependent p53 polyubiquitination and degradation. Mdm2 on its own is a monoubiquitin E3 ligase for p53, but is converted to a p53 polyubiquitin E3 ligase by MdmX through their RING-RING domain interactions. MdmX acts as an activator as well as a substrate of Mdm2/MdmX E3 complex. The insufficiency of Mdm2 for p53 polyubiquitination also demands other p53 E3 ligases or E4 factors be incorporated into the p53 degradation arena. Deubiquitinases nullify the effects of E3 actions and reverse the ubiquitination process, which permits a diverse and dynamic pattern of p53 stability control. Unsurprisingly, stress signals target MdmX to disengage the p53/Mdm2 feedback loop for timely and appropriate p53 responses to these stresses.
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44
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Taylor JR, Lehmann BD, Chappell WH, Abrams SL, Steelman LS, McCubrey JA. Cooperative effects of Akt-1 and Raf-1 on the induction of cellular senescence in doxorubicin or tamoxifen treated breast cancer cells. Oncotarget 2012; 2:610-26. [PMID: 21881167 PMCID: PMC3248208 DOI: 10.18632/oncotarget.315] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Escape from cellular senescence induction is a potent mechanism for chemoresistance. Cellular senescence can be induced in breast cancer cell lines by the removal of estrogen signaling with tamoxifen or by the accumulation of DNA damage induced by the chemotherapeutic drug doxorubicin. Long term culturing of the hormone-sensitive breast cancer cell line MCF-7 in doxorubicin (MCF-7/DoxR) reduced the ability of doxorubicin, but not tamoxifen, to induce senescence. Two pathways that are often upregulated in chemo- and hormonal-resistance are the PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways. To determine if active Akt-1 and Raf-1 can influence drug-induced senescence, we stably introduced activated ΔAkt-1(CA) and ΔRaf-1(CA) into drug-sensitive and doxorubicin-resistant cells. Expression of a constitutively-active Raf-1 construct resulted in higher baseline senescence, indicating these cells possessed the ability to undergo oncogene-induced-senescence. Constitutive activation of the Akt pathway significantly decreased drug-induced senescence in response to doxorubicin but not tamoxifen in MCF-7 cells. However, constitutive Akt-1 activation in drug-resistant cells containing high levels of active ERK completely escaped cellular senescence induced by doxorubicin and tamoxifen. These results indicate that up regulation of the Ras/PI3K/PTEN/Akt/mTOR pathway in the presence of elevated Ras/Raf/MEK/ERK signaling together can contribute to drug-resistance by diminishing cell senescence in response to chemotherapy. Understanding how breast cancers containing certain oncogenic mutations escape cell senescence in response to chemotherapy and hormonal based therapies may provide insights into the design of more effective drug combinations for the treatment of breast cancer.
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Affiliation(s)
- Jackson R Taylor
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University Greenville, NC 27858 USA
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45
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Li X, Gilkes D, Li B, Cheng Q, Pernazza D, Lawrence H, Lawrence N, Chen J. Abnormal MDMX degradation in tumor cells due to ARF deficiency. Oncogene 2011; 31:3721-32. [PMID: 22120712 PMCID: PMC3290737 DOI: 10.1038/onc.2011.534] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
MDMX is a hetero dimeric partner of MDM2 and a critical regulator of p53. MDMX level is generally elevated in tumors with wild type p53 and contributes to p53 inactivation. MDMX degradation is controlled in part by MDM2-mediated ubiquitination. Here we show that MDMX turnover is highly responsive to changes in MDM2 level in non-transformed cells, but not in tumor cells. We found that loss of ARF expression, which occurs in most tumors with wild type p53, significantly reduces MDMX sensitivity to MDM2. Restoration of ARF expression in tumor cells enables MDM2 to degrade MDMX in a dose-dependent fashion. ARF binds to MDM2 and stimulates a second-site interaction between the central region of MDM2 and MDMX, thus increases MDMX-MDM2 binding and MDMX ubiquitination. These results reveal an important abnormality in the p53 regulatory pathway as a consequence of ARF deficiency. Loss of ARF during tumor development not only prevents p53 stabilization by proliferative stress, but also causes accumulation of MDMX that compromises p53 activity. This phenomenon may reduce the clinical efficacy of MDM2-specific inhibitors by preventing MDMX down regulation.
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Affiliation(s)
- X Li
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, FL, USA
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46
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Current World Literature. Curr Opin Oncol 2011; 23:303-10. [DOI: 10.1097/cco.0b013e328346cbfa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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47
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Gutekunst M, Oren M, Weilbacher A, Dengler MA, Markwardt C, Thomale J, Aulitzky WE, van der Kuip H. p53 hypersensitivity is the predominant mechanism of the unique responsiveness of testicular germ cell tumor (TGCT) cells to cisplatin. PLoS One 2011; 6:e19198. [PMID: 21532991 PMCID: PMC3080918 DOI: 10.1371/journal.pone.0019198] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 03/29/2011] [Indexed: 12/20/2022] Open
Abstract
Consistent with the excellent clinical results in testicular germ cell tumors
(TGCT), most cell lines derived from this cancer show an exquisite sensitivity
to Cisplatin. It is well accepted that the high susceptibility of TGCT cells to
apoptosis plays a central role in this hypersensitive phenotype. The role of the
tumor suppressor p53 in this response, however, remains controversial. Here we
show that siRNA-mediated silencing of p53 is sufficient to completely abrogate
hypersensitivity not only to Cisplatin but also to non-genotoxic inducers of p53
such as the Mdm2 antagonist Nutlin-3 and the proteasome inhibitor Bortezomib.
The close relationship between p53 protein levels and induction of apoptosis is
lost upon short-term differentiation, indicating that this predominant
pro-apoptotic function of p53 is unique in pluripotent embryonal carcinoma (EC)
cells. RNA interference experiments as well as microarray analysis demonstrated
a central role of the pro-apoptotic p53 target gene NOXA in the p53-dependent
apoptotic response of these cells. In conclusion, our data indicate that the
hypersensitivity of TGCT cells is a result of their unique sensitivity to p53
activation. Furthermore, in the very specific cellular context of germ
cell-derived pluripotent EC cells, p53 function appears to be limited to
induction of apoptosis.
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Affiliation(s)
- Matthias Gutekunst
- Dr Margarete-Fischer-Bosch Institute of Clinical Pharmacology and
University of Tuebingen, Stuttgart, Germany
| | - Moshe Oren
- Department of Molecular Cell Biology, Weizmann Institute of Science,
Rehovot, Israel
| | - Andrea Weilbacher
- Dr Margarete-Fischer-Bosch Institute of Clinical Pharmacology and
University of Tuebingen, Stuttgart, Germany
| | - Michael A. Dengler
- Dr Margarete-Fischer-Bosch Institute of Clinical Pharmacology and
University of Tuebingen, Stuttgart, Germany
| | - Christiane Markwardt
- Dr Margarete-Fischer-Bosch Institute of Clinical Pharmacology and
University of Tuebingen, Stuttgart, Germany
| | - Jürgen Thomale
- Institute for Cell Biology, University of Duisburg-Essen Medical School,
Essen, Germany
| | - Walter E. Aulitzky
- 2 Department of Internal Medicine, Robert-Bosch-Hospital, Stuttgart,
Germany
| | - Heiko van der Kuip
- Dr Margarete-Fischer-Bosch Institute of Clinical Pharmacology and
University of Tuebingen, Stuttgart, Germany
- * E-mail:
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48
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Disruption of the MDM2-p53 interaction strongly potentiates p53-dependent apoptosis in cisplatin-resistant human testicular carcinoma cells via the Fas/FasL pathway. Cell Death Dis 2011; 2:e148. [PMID: 21509038 PMCID: PMC3122064 DOI: 10.1038/cddis.2011.33] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Wild-type p53 has a major role in the response and execution of apoptosis after chemotherapy in many cancers. Although high levels of wild-type p53 and hardly any TP53 mutations are found in testicular cancer (TC), chemotherapy resistance is still observed in a significant subgroup of TC patients. In the present study, we demonstrate that p53 resides in a complex with MDM2 at higher cisplatin concentrations in cisplatin-resistant human TC cells compared with cisplatin-sensitive TC cells. Inhibition of the MDM2–p53 interaction using either Nutlin-3 or MDM2 RNA interference resulted in hyperactivation of the p53 pathway and a strong induction of apoptosis in cisplatin-sensitive and -resistant TC cells. Suppression of wild-type p53 induced resistance to Nutlin-3 in TC cells, demonstrating the key role of p53 for Nutlin-3 sensitivity. More specifically, our results indicate that p53-dependent induction of Fas membrane expression (∼threefold) and enhanced Fas/FasL interactions at the cell surface are important mechanisms of Nutlin-3-induced apoptosis in TC cells. Importantly, an analogous Fas-dependent mechanism of apoptosis upon Nutlin-3 treatment is executed in wild-type p53 expressing Hodgkin lymphoma and acute myeloid leukaemia cell lines. Finally, we demonstrate that Nutlin-3 strongly augmented cisplatin-induced apoptosis and cell kill via the Fas death receptor pathway. This effect is most pronounced in cisplatin-resistant TC cells.
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49
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Functions of MDMX in the modulation of the p53-response. J Biomed Biotechnol 2011; 2011:876173. [PMID: 21541195 PMCID: PMC3085504 DOI: 10.1155/2011/876173] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/21/2011] [Indexed: 12/21/2022] Open
Abstract
The MDM family proteins MDM2 and MDMX are two critical regulators of the p53 tumor suppressor protein. Expression of both proteins is necessary for allowing the embryonal development by keeping the activity of p53 in check. Upon stresses that need to activate p53 to perform its function as guardian of the genome, p53 has to be liberated from these two inhibitors. In this review, we will discuss the various mechanisms by which MDMX protein levels are downregulated upon various types of stress, including posttranslational modifications of the MDMX protein and the regulation of mdmx mRNA expression, including alternative splicing. In addition, the putative function(s) of the described MDMX splice variants, particularly in tumor development, will be discussed. Lastly, in contrast to common belief, we have recently shown the existence of a p53-MDMX feedback loop, which is important for dampening the p53-response at later phases after genotoxic stress.
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50
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Cross B, Chen L, Cheng Q, Li B, Yuan ZM, Chen J. Inhibition of p53 DNA binding function by the MDM2 protein acidic domain. J Biol Chem 2011; 286:16018-29. [PMID: 21454483 DOI: 10.1074/jbc.m111.228981] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MDM2 regulates p53 predominantly by promoting p53 ubiquitination. However, ubiquitination-independent mechanisms of MDM2 have also been implicated. Here we show that MDM2 inhibits p53 DNA binding activity in vitro and in vivo. MDM2 binding promotes p53 to adopt a mutant-like conformation, losing reactivity to antibody Pab1620, while exposing the Pab240 epitope. The acidic domain of MDM2 is required to induce p53 conformational change and inhibit p53 DNA binding. Alternate reading frame binding to the MDM2 acidic domain restores p53 wild type conformation and rescues DNA binding activity. Furthermore, histone methyl transferase SUV39H1 binding to the MDM2 acidic domain also restores p53 wild type conformation and allows p53-MDM2-SUV39H1 complex to bind DNA. These results provide further evidence for an ubiquitination-independent mechanism of p53 regulation by MDM2 and reveal how MDM2-interacting repressors gain access to p53 target promoters and repress transcription. Furthermore, we show that the MDM2 inhibitor Nutlin cooperates with the proteasome inhibitor Bortezomib by stimulating p53 DNA binding and transcriptional activity, providing a rationale for combination therapy using proteasome and MDM2 inhibitors.
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Affiliation(s)
- Brittany Cross
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, Florida 33612, USA
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