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Wang W, Albadari N, Du Y, Fowler JF, Sang HT, Xian W, McKeon F, Li W, Zhou J, Zhang R. MDM2 Inhibitors for Cancer Therapy: The Past, Present, and Future. Pharmacol Rev 2024; 76:414-453. [PMID: 38697854 PMCID: PMC11068841 DOI: 10.1124/pharmrev.123.001026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/28/2023] [Accepted: 01/16/2024] [Indexed: 05/05/2024] Open
Abstract
Since its discovery over 35 years ago, MDM2 has emerged as an attractive target for the development of cancer therapy. MDM2's activities extend from carcinogenesis to immunity to the response to various cancer therapies. Since the report of the first MDM2 inhibitor more than 30 years ago, various approaches to inhibit MDM2 have been attempted, with hundreds of small-molecule inhibitors evaluated in preclinical studies and numerous molecules tested in clinical trials. Although many MDM2 inhibitors and degraders have been evaluated in clinical trials, there is currently no Food and Drug Administration (FDA)-approved MDM2 inhibitor on the market. Nevertheless, there are several current clinical trials of promising agents that may overcome the past failures, including agents granted FDA orphan drug or fast-track status. We herein summarize the research efforts to discover and develop MDM2 inhibitors, focusing on those that induce MDM2 degradation and exert anticancer activity, regardless of the p53 status of the cancer. We also describe how preclinical and clinical investigations have moved toward combining MDM2 inhibitors with other agents, including immune checkpoint inhibitors. Finally, we discuss the current challenges and future directions to accelerate the clinical application of MDM2 inhibitors. In conclusion, targeting MDM2 remains a promising treatment approach, and targeting MDM2 for protein degradation represents a novel strategy to downregulate MDM2 without the side effects of the existing agents blocking p53-MDM2 binding. Additional preclinical and clinical investigations are needed to finally realize the full potential of MDM2 inhibition in treating cancer and other chronic diseases where MDM2 has been implicated. SIGNIFICANCE STATEMENT: Overexpression/amplification of the MDM2 oncogene has been detected in various human cancers and is associated with disease progression, treatment resistance, and poor patient outcomes. This article reviews the previous, current, and emerging MDM2-targeted therapies and summarizes the preclinical and clinical studies combining MDM2 inhibitors with chemotherapy and immunotherapy regimens. The findings of these contemporary studies may lead to safer and more effective treatments for patients with cancers overexpressing MDM2.
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Affiliation(s)
- Wei Wang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Najah Albadari
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Yi Du
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Josef F Fowler
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Hannah T Sang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Wa Xian
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Frank McKeon
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Wei Li
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Jia Zhou
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
| | - Ruiwen Zhang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy (W.W., Y.D., J.F.F., H.T.S., R.Z.), Drug Discovery Institute (W.W., R.Z.), Stem Cell Center, Department of Biology and Biochemistry (W.X., F.M.), University of Houston, Houston, Texas; College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee (N.A., W.L.); and Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (J.Z.)
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Mokhtari K, Peymani M, Rashidi M, Hushmandi K, Ghaedi K, Taheriazam A, Hashemi M. Colon cancer transcriptome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:49-82. [PMID: 37059270 DOI: 10.1016/j.pbiomolbio.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/16/2023]
Abstract
Over the last four decades, methodological innovations have continuously changed transcriptome profiling. It is now feasible to sequence and quantify the transcriptional outputs of individual cells or thousands of samples using RNA sequencing (RNA-seq). These transcriptomes serve as a connection between cellular behaviors and their underlying molecular mechanisms, such as mutations. This relationship, in the context of cancer, provides a chance to unravel tumor complexity and heterogeneity and uncover novel biomarkers or treatment options. Since colon cancer is one of the most frequent malignancies, its prognosis and diagnosis seem to be critical. The transcriptome technology is developing for an earlier and more accurate diagnosis of cancer which can provide better protectivity and prognostic utility to medical teams and patients. A transcriptome is a whole set of expressed coding and non-coding RNAs in an individual or cell population. The cancer transcriptome includes RNA-based changes. The combined genome and transcriptome of a patient may provide a comprehensive picture of their cancer, and this information is beginning to affect treatment decision-making in real-time. A full assessment of the transcriptome of colon (colorectal) cancer has been assessed in this review paper based on risk factors such as age, obesity, gender, alcohol use, race, and also different stages of cancer, as well as non-coding RNAs like circRNAs, miRNAs, lncRNAs, and siRNAs. Similarly, they have been examined independently in the transcriptome study of colon cancer.
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Affiliation(s)
- Khatere Mokhtari
- Department of Modern Biology, ACECR Institute of Higher Education (Isfahan Branch), Isfahan, Iran
| | - Maryam Peymani
- Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
| | - Mohsen Rashidi
- Department Pharmacology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, 4815733971, Iran; The Health of Plant and Livestock Products Research Center, Mazandaran University of Medical Sciences, Sari, 4815733971, Iran
| | - Kiavash Hushmandi
- Department of Food Hygiene and Quality Control, Division of Epidemiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Kamran Ghaedi
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
| | - Afshin Taheriazam
- Farhikhtegan Medical Convergence Sciences Research Center, Farhikhtegan Hospital Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; Department of Orthopedics, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | - Mehrdad Hashemi
- Farhikhtegan Medical Convergence Sciences Research Center, Farhikhtegan Hospital Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
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Huang H, Park S, Zhang H, Park S, Kwon W, Kim E, Zhang X, Jang S, Yoon D, Choi SK, Yi JK, Kim SH, Dong Z, Lee MH, Ryoo Z, Kim MO. Targeting AKT with costunolide suppresses the growth of colorectal cancer cells and induces apoptosis in vitro and in vivo. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:114. [PMID: 33785035 PMCID: PMC8010944 DOI: 10.1186/s13046-021-01895-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/25/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Colorectal cancer (CRC) is a clinically challenging malignant tumor worldwide. As a natural product and sesquiterpene lactone, Costunolide (CTD) has been reported to possess anticancer activities. However, the regulation mechanism and precise target of this substance remain undiscovered in CRC. In this study, we found that CTD inhibited CRC cell proliferation in vitro and in vivo by targeting AKT. METHODS Effects of CTD on colon cancer cell growth in vitro were evaluated in cell proliferation assays, migration and invasion, propidium iodide, and annexin V-staining analyses. Targets of CTD were identified utilizing phosphoprotein-specific antibody array; Costunolide-sepharose conjugated bead pull-down analysis and knockdown techniques. We investigated the underlying mechanisms of CTD by ubiquitination, immunofluorescence staining, and western blot assays. Cell-derived tumour xenografts (CDX) in nude mice and immunohistochemistry were used to assess anti-tumour effects of CTD in vivo. RESULTS CTD suppressed the proliferation, anchorage-independent colony growth and epithelial-mesenchymal transformation (EMT) of CRC cells including HCT-15, HCT-116 and DLD1. Besides, the CTD also triggered cell apoptosis and cell cycle arrest at the G2/M phase. The CTD activates and induces p53 stability by inhibiting MDM2 ubiquitination via the suppression of AKT's phosphorylation in vitro. The CTD suppresses cell growth in a p53-independent fashion manner; p53 activation may contribute to the anticancer activity of CTD via target AKT. Finally, the CTD decreased the volume of CDX tumors without of the body weight loss and reduced the expression of AKT-MDM2-p53 signaling pathway in xenograft tumors. CONCLUSIONS Our project has uncovered the mechanism underlying the biological activity of CTD in colon cancer and confirmed the AKT is a directly target of CTD. All of which These results revealed that CTD might be a new AKT inhibitor in colon cancer treatment, and CTD is worthy of further exploration in preclinical and clinical trials.
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Affiliation(s)
- Hai Huang
- Department of Animal Science and Biotechnology, ITRD, Kyungpook National University, Sangju, 37224, Republic of Korea
| | - Song Park
- Core Protein Resources Center, DGIST, Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
| | - Haibo Zhang
- Department of Animal Science and Biotechnology, ITRD, Kyungpook National University, Sangju, 37224, Republic of Korea
| | - Sijun Park
- School of Life Science, Kyungpook National University, Daegu, Republic of Korea
| | - Wookbong Kwon
- Division of Biotechnology, DGIST, Daegu, Republic of Korea
| | - Enugyung Kim
- Department of Animal Science and Biotechnology, ITRD, Kyungpook National University, Sangju, 37224, Republic of Korea
| | - Xiujuan Zhang
- Department of Pulmonary and Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Soyoung Jang
- School of Life Science, Kyungpook National University, Daegu, Republic of Korea
| | - Duhak Yoon
- Department of Animal Science and Biotechnology, ITRD, Kyungpook National University, Sangju, 37224, Republic of Korea
| | - Seong-Kyoon Choi
- Core Protein Resources Center, DGIST, Daegu, Republic of Korea.,Division of Biotechnology, DGIST, Daegu, Republic of Korea
| | - Jun-Koo Yi
- Gyeongsangbuk-do Livestock Research Institute, Yeongju, South Korea
| | - Sung-Hyun Kim
- Department of Bio-Medical Analysis, Korea Polytechnic College, Chungnam, Korea
| | - Zigang Dong
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450008, Henan, China
| | - Mee-Hyun Lee
- College of Korean Medicine, Dongshin University, Naju, Jeollanamdo, 58245, Republic of Korea.
| | - Zaeyoung Ryoo
- School of Life Science, Kyungpook National University, Daegu, Republic of Korea.
| | - Myoung Ok Kim
- Department of Animal Science and Biotechnology, ITRD, Kyungpook National University, Sangju, 37224, Republic of Korea.
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Li W, Peng X, Lang J, Xu C. Targeting Mouse Double Minute 2: Current Concepts in DNA Damage Repair and Therapeutic Approaches in Cancer. Front Pharmacol 2020; 11:631. [PMID: 32477121 PMCID: PMC7232544 DOI: 10.3389/fphar.2020.00631] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/21/2020] [Indexed: 01/14/2023] Open
Abstract
Defects in DNA damage repair may cause genome instability and cancer development. The tumor suppressor gene p53 regulates cell cycle arrest to allow time for DNA repair. The oncoprotein mouse double minute 2 (MDM2) promotes cell survival, proliferation, invasion, and therapeutic resistance in many types of cancer. The major role of MDM2 is to inhibit p53 activity and promote its degradation. In this review, we describe the influence of MDM2 on genomic instability, the role of MDM2 on releasing p53 and binding DNA repair proteins to inhibit repair, and the regulation network of MDM2 including its transcriptional modifications, protein stability, and localization following DNA damage in genome integrity maintenance and in MDM2-p53 axis control. We also discuss p53-dependent and p53 independent oncogenic function of MDM2 and the outcomes of clinical trials that have been used with clinical inhibitors targeting p53-MDM2 to treat certain cancers.
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Affiliation(s)
- Wen Li
- Cancer Clinical Research Center & Integrative Cancer Center, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xinhao Peng
- Cancer Clinical Research Center & Integrative Cancer Center, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.,Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jinyi Lang
- Cancer Clinical Research Center & Integrative Cancer Center, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.,Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Chuan Xu
- Cancer Clinical Research Center & Integrative Cancer Center, Sichuan Cancer Hospital & Institute Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
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Wang S, Huang J, Li C, Zhao L, Wong CC, Zhai J, Zhou Y, Deng W, Zeng Y, Gao S, Zhang Y, Wang G, Guan XY, Wei H, Wong SH, He HH, Shay JW, Yu J. MAP9 Loss Triggers Chromosomal Instability, Initiates Colorectal Tumorigenesis, and Is Associated with Poor Survival of Patients with Colorectal Cancer. Clin Cancer Res 2019; 26:746-757. [PMID: 31662330 DOI: 10.1158/1078-0432.ccr-19-1611] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 09/12/2019] [Accepted: 10/25/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE Chromosomal instability (CIN) is a common phenomenon in colorectal cancer, but its role and underlying cause remain unknown. We have identified that mitotic regulator microtubule-associated protein 9 (MAP9) is a critical regulator of CIN in colorectal cancer. We thus studied the effect of MAP9 loss on colorectal cancer in Map9-knockout mice and in cell lines. EXPERIMENTAL DESIGN We generated colon epithelial-specific Map9-knockout mice and evaluated colorectal cancer development. Effect of Map9 knockout on colorectal cancer progression was determined in chemical or ApcMin /+ -induced colorectal cancer. Molecular mechanism of MAP9 was determined using spectral karyotyping, microtubule assays, and whole-genome sequencing (WGS). Clinical significance of MAP9 was examined in 141 patients with CRC. RESULTS Spontaneous colonic tumors (9.1%) were developed in colon epithelium-specific Map9-knockout mice at 17 months, but none was observed in wild-type littermates. Map9 deletion accelerated colorectal cancer formation both in ApcMin /+ mice and azoxymethane-treated mice, and reduced survival in ApcMin /+ mice. Mechanistically, MAP9 stabilized microtubules and mediated mitotic spindle assembly. MAP9 also maintained the spindle pole integrity and protected K-fiber from depolymerization at spindle poles. MAP9 loss induced severe mitosis failure, chromosome segregation errors, and aneuploidy, leading to transformation of normal colon epithelial cells. WGS confirmed enhanced CIN in intestinal tumors from Map9 knockout ApcMin /+ mice. In patients with colorectal cancer, MAP9 was frequently silenced and its downregulation was associated with poor survival. CONCLUSIONS MAP9 is a microtubule stabilizer that contributes to spindle stability and inhibits colorectal tumorigenesis, supporting the role of MAP9 as a tumor suppressor for preventing CIN in colorectal cancer.
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Affiliation(s)
- Shiyan Wang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Junzhe Huang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Chuangen Li
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Liuyang Zhao
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Chi Chun Wong
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Jianning Zhai
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Yunfei Zhou
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Wen Deng
- School of Nursing, Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Yong Zeng
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Shanshan Gao
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Yanquan Zhang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Guoping Wang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Xin Yuan Guan
- Department of Clinical Oncology, The University of Hong Kong, Hong Kong
| | - Hong Wei
- Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Sunny H Wong
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong
| | - Housheng H He
- Princess Margaret Cancer Center/University Health Network, Toronto, Ontario, Canada
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jun Yu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong.
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Cao Z, Xue J, Cheng Y, Wang J, Liu Y, Li H, Jiang W, Li G, Gui Y, Zhang X. MDM2 promotes genome instability by ubiquitinating the transcription factor HBP1. Oncogene 2019; 38:4835-4855. [PMID: 30816344 PMCID: PMC6756050 DOI: 10.1038/s41388-019-0761-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 12/09/2018] [Accepted: 02/10/2019] [Indexed: 12/26/2022]
Abstract
Genome instability is a common feature of tumor cells, and the persistent presence of genome instability is a potential mechanism of tumorigenesis. The E3 ubiquitin ligase MDM2 is intimately involved in genome instability, but its mechanisms are unclear. Our data demonstrated that the transcription factor HBP1 is a target of MDM2. MDM2 facilitates HBP1 proteasomal degradation by ubiquitinating HBP1, regardless of p53 status, thus attenuating the transcriptional inhibition of HBP1 in the expression of its target genes, such as the DNA methyltransferase DNMT1 and histone methyltransferase EZH2, which results in global DNA hypermethylation and histone hypermethylation and ultimately genome instability. The repression of HBP1 by MDM2 finally promotes cell growth and tumorigenesis. Next, we thoroughly explored the regulatory mechanism of the MDM2/HBP1 axis in DNA damage repair following ionizing radiation. Our data indicated that MDM2 overexpression-mediated repression of HBP1 delays DNA damage repair and causes cell death in a p53-independent manner. This investigation elucidated the mechanism of how MDM2 promotes genome instability and enhances tumorigenesis in the absence of p53, thus providing a theoretical and experimental basis for targeting MDM2 as a cancer therapy.
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Affiliation(s)
- Zhengyi Cao
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Junhui Xue
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Yuning Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Jiyin Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Yujuan Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Hui Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Wei Jiang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Gang Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Yaoting Gui
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen-Peking University-the Hong Kong University of Science and Technology Medical Center, Shenzhen, 518000, P. R. China
| | - Xiaowei Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, P. R. China.
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Gronroos E, López-García C. Tolerance of Chromosomal Instability in Cancer: Mechanisms and Therapeutic Opportunities. Cancer Res 2018; 78:6529-6535. [PMID: 30420473 DOI: 10.1158/0008-5472.can-18-1958] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/24/2018] [Accepted: 09/12/2018] [Indexed: 11/16/2022]
Abstract
Chromosomal instability (CIN) is the result of ongoing changes in the number (aneuploidy) and structure of chromosomes. CIN is induced by chromosome missegregation in mitosis and leads to karyotypic diversity within the cancer cell population, thereby adding to intratumor heterogeneity. Regardless of the overall pro-oncogenic function of CIN, its onset is typically detrimental for cell fitness and thus tumors must develop CIN-tolerance mechanisms in order to propagate. There is overwhelming genetic and functional evidence linking mutations in the tumor suppressor TP53 with CIN-tolerance. However, the pathways leading to p53 activation following chromosome missegregation remain controversial. Recently, additional mechanisms have been identified in CIN-surveillance, resulting in a more complex network of pathways acting independently or in cooperation with p53. Tolerance might also be achieved by modifying aspects of the cancer cell physiology in order to attenuate CIN or by adaptation to the consequences of aneuploid karyotypes. In this review, we summarize the current knowledge about p53-dependent and -independent mechanisms of CIN-tolerance in cancer, the adaptations observed in CIN cells buffering CIN levels, its consequences for cellular homeostasis, and the potential of exploiting these adaptations in order to design new cancer therapies.
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Affiliation(s)
- Eva Gronroos
- Translational Cancer Therapeutics Laboratory, Francis Crick Institute, London, United Kingdom
| | - Carlos López-García
- Translational Cancer Therapeutics Laboratory, Francis Crick Institute, London, United Kingdom. .,National Heart and Lung Institute, Airway Disease Group, Faculty of Medicine, Imperial College London, London, United Kingdom
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8
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Greenawalt EJ, Edmonds MD, Jain N, Adams CM, Mitra R, Eischen CM. Targeting of SGK1 by miR-576-3p Inhibits Lung Adenocarcinoma Migration and Invasion. Mol Cancer Res 2018; 17:289-298. [PMID: 30257988 DOI: 10.1158/1541-7786.mcr-18-0364] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/28/2018] [Accepted: 09/06/2018] [Indexed: 01/07/2023]
Abstract
Metastatic lung cancer is common in patients with lung adenocarcinoma, but the molecular mechanisms of metastasis remain incompletely resolved. miRNA regulate gene expression and contribute to cancer development and progression. This report identifies miR-576-3p and its mechanism of action in lung cancer progression. miR-576-3p was determined to be significantly decreased in clinical specimens of late-stage lung adenocarcinoma. Overexpression of miR-576-3p in lung adenocarcinoma cells decreased mesenchymal marker expression and inhibited migration and invasion. Inhibition of miR-576-3p in nonmalignant lung epithelial cells increased migration and invasion as well as mesenchymal markers. Serum/glucocorticoid-regulated kinase 1 (SGK1) was a direct target of miR-576-3p, and modulation of miR-576-3p levels led to alterations in SGK1 protein and mRNA as well as changes in activation of its downstream target linked to metastasis, N-myc downstream regulated 1 (NDRG1). Loss of the ability of miR-576-3p to bind the 3'-UTR of SGK1 rescued the inhibition in migration and invasion observed with miR-576-3p overexpression. In addition, increased SGK1 levels were detected in lung adenocarcinoma patient samples expressing mesenchymal markers, and pharmacologic inhibition of SGK1 resulted in a similar inhibition of migration and invasion of lung adenocarcinoma cells as observed with miR-576-3p overexpression. Together, these results reveal miR-576-3p downregulation is selected for in late-stage lung adenocarcinoma due to its ability to inhibit migration and invasion by targeting SGK1. Furthermore, these results also support targeting SGK1 as a potential therapeutic for lung adenocarcinoma. IMPLICATIONS: This study reveals SGK1 inhibition with miR-576-3p or pharmacologically inhibits migration and invasion of lung adenocarcinoma, providing mechanistic insights into late-stage lung adenocarcinoma and a potential new treatment avenue.
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Affiliation(s)
- Evan J Greenawalt
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Mick D Edmonds
- Department of Genetics, University of Alabama, Birmingham, Alabama
| | - Neha Jain
- Vanderbilt Ingram Cancer Center, Nashville, Tennessee
| | - Clare M Adams
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ramkrishna Mitra
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.
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9
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Li D, Tavana O, Sun SC, Gu W. Peli1 Modulates the Subcellular Localization and Activity of Mdmx. Cancer Res 2018; 78:2897-2910. [PMID: 29523541 PMCID: PMC5984691 DOI: 10.1158/0008-5472.can-17-3531] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/12/2018] [Accepted: 03/05/2018] [Indexed: 12/21/2022]
Abstract
Mdm2 and Mdmx, both major repressors of p53 in human cancers, are predominantly localized to the nucleus and cytoplasm, respectively. The mechanism by which subcellular localization of Mdmx is regulated remains unclear. In this study, we identify the E3 ligase Peli1 as a major binding partner and regulator of Mdmx in human cells. Peli1 bound Mdmx in vitro and in vivo and promoted high levels of ubiquitination of Mdmx. Peli1-mediated ubiquitination was degradation-independent, promoting cytoplasmic localization of Mdmx, which in turn resulted in p53 activation. Consistent with this, knockdown or knockout Peli1 in human cancer cells induced nuclear localization of Mdmx and suppressed p53 activity. Myc-induced tumorigenesis was accelerated in Peli1-null mice and associated with downregulation of p53 function. Clinical samples of human cutaneous melanoma had decreased Peli1 expression, which was associated with poor overall survival. Together, these results demonstrate that Peli1 acts as a critical factor for the Mdmx-p53 axis by modulating the subcellular localization and activity of Mdmx, thus revealing a novel mechanism of Mdmx deregulation in human cancers.Significance: Peli1-mediated regulation of Mdmx, a major inhibitor of p53, provides critical insight into activation of p53 function in human cancers. Cancer Res; 78(11); 2897-910. ©2018 AACR.
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Affiliation(s)
- Dawei Li
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Omid Tavana
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Shao-Cong Sun
- Department of Immunology, the University of Texas MD Anderson Cancer Center, MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Wei Gu
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York.
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10
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MDMX acidic domain inhibits p53 DNA binding in vivo and regulates tumorigenesis. Proc Natl Acad Sci U S A 2018; 115:E3368-E3377. [PMID: 29581299 DOI: 10.1073/pnas.1719090115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The MDM2 homolog MDMX oncoprotein is indispensable for inhibition of p53 during normal embryonic development and malignant transformation, yet how MDMX harnesses p53 functions is unclear. In addition to a canonical N-terminal p53-binding domain, recent work suggests the central acidic domain of MDMX regulates p53 interaction through intramolecular mimicry and engages in second-site interaction with the p53 core domain in vitro. To test the physiological relevance of these interactions, we generated an MDMX knockin mouse having substitutions in a conserved WW motif necessary for these functions (W201S/W202G). Notably, MDMXSG cells have normal p53 level but increased p53 DNA binding and target gene expression, and rapidly senesce. In vivo, MDMXSG inhibits early-phase disease in Eµ-Myc transgenic mice but accelerates the onset of lethal lymphoma and shortens overall survival. Therefore, MDMX is an important regulator of p53 DNA binding, which complements the role of MDM2 in regulating p53 level. Furthermore, the results suggest that the WW motif has dual functions that regulate p53 and inhibit Myc-driven lymphomas independent of p53.
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11
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Zhao Y, Tan M, Liu X, Xiong X, Sun Y. Inactivation of ribosomal protein S27-like confers radiosensitivity via the Mdm2-p53 and Mdm2-MRN-ATM axes. Cell Death Dis 2018; 9:145. [PMID: 29396424 PMCID: PMC5833388 DOI: 10.1038/s41419-017-0192-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 01/21/2023]
Abstract
RPS27L (ribosomal protein S27-like) is an evolutionarily conserved ribosomal protein and a direct p53 target. We recently reported that Rps27l disruption triggers ribosomal stress to induce p53, causing postnatal death, which can be rescued by Trp53+/−. Whether and how Rps27l modulates radiosensitivity is unknown. Here we report that Rps27l−/−; Trp53+/− mice are extremely sensitive to radiation due to reduced proliferation and massive induction of apoptosis in radiation-sensitive organs. Mechanistically, the radiation sensitivity is mediated by two signaling pathways: (1) activated p53 pathway due to imbalanced Mdm2/Mdm4 levels and reduced E3 ligase activity; and (2) reduced DNA damage response due to reduced MRN/Atm signal as a result of elevated Mdm2 binding of Nbs1 to inhibit Nbs1–Atm binding and subsequent Atm activation. Indeed, heterozygous deletion of Mdm2 restores the MRN/Atm signal. Collectively, our study revealed a physiological condition under which Rps27l regulates the Mdm2/p53 and MRN/Atm axes to maintain DNA damage response and to confer radioprotection in vivo.
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Affiliation(s)
- Yongchao Zhao
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China. .,Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA. .,Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Mingjia Tan
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Xia Liu
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiufang Xiong
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China. .,Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
| | - Yi Sun
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China. .,Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA. .,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China.
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12
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Mitra R, Chen X, Greenawalt EJ, Maulik U, Jiang W, Zhao Z, Eischen CM. Decoding critical long non-coding RNA in ovarian cancer epithelial-to-mesenchymal transition. Nat Commun 2017; 8:1604. [PMID: 29150601 PMCID: PMC5693921 DOI: 10.1038/s41467-017-01781-0] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 10/16/2017] [Indexed: 12/17/2022] Open
Abstract
Long non-coding RNA (lncRNA) are emerging as contributors to malignancies. Little is understood about the contribution of lncRNA to epithelial-to-mesenchymal transition (EMT), which correlates with metastasis. Ovarian cancer is usually diagnosed after metastasis. Here we report an integrated analysis of >700 ovarian cancer molecular profiles, including genomic data sets, from four patient cohorts identifying lncRNA DNM3OS, MEG3, and MIAT overexpression and their reproducible gene regulation in ovarian cancer EMT. Genome-wide mapping shows 73% of MEG3-regulated EMT-linked pathway genes contain MEG3 binding sites. DNM3OS overexpression, but not MEG3 or MIAT, significantly correlates to worse overall patient survival. DNM3OS knockdown results in altered EMT-linked genes/pathways, mesenchymal-to-epithelial transition, and reduced cell migration and invasion. Proteotranscriptomic characterization further supports the DNM3OS and ovarian cancer EMT connection. TWIST1 overexpression and DNM3OS amplification provides an explanation for increased DNM3OS levels. Therefore, our results elucidate lncRNA that regulate EMT and demonstrate DNM3OS specifically contributes to EMT in ovarian cancer.
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Affiliation(s)
- Ramkrishna Mitra
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Xi Chen
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Evan J Greenawalt
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Ujjwal Maulik
- Department of Computer Science and Engineering, Jadavpur University, Jadavpur, 700032, India
| | - Wei Jiang
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Christine M Eischen
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
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13
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Adams CM, Mitra R, Gong JZ, Eischen CM. Non-Hodgkin and Hodgkin Lymphomas Select for Overexpression of BCLW. Clin Cancer Res 2017; 23:7119-7129. [PMID: 28855351 PMCID: PMC5700812 DOI: 10.1158/1078-0432.ccr-17-1144] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/21/2017] [Accepted: 08/23/2017] [Indexed: 01/25/2023]
Abstract
Purpose: B-cell lymphomas must acquire resistance to apoptosis during their development. We recently discovered BCLW, an antiapoptotic BCL2 family member thought only to contribute to spermatogenesis, was overexpressed in diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. To gain insight into the contribution of BCLW to B-cell lymphomas and its potential to confer resistance to BCL2 inhibitors, we investigated the expression of BCLW and the other antiapoptotic BCL2 family members in six different B-cell lymphomas.Experimental Design: We performed a large-scale gene expression analysis of datasets comprising approximately 2,300 lymphoma patient samples, including non-Hodgkin and Hodgkin lymphomas as well as indolent and aggressive lymphomas. Data were validated experimentally with qRT-PCR and IHC.Results: We report BCLW is significantly overexpressed in aggressive and indolent lymphomas, including DLBCL, Burkitt, follicular, mantle cell, marginal zone, and Hodgkin lymphomas. Notably, BCLW was preferentially overexpressed over that of BCL2 and negatively correlated with BCL2 in specific lymphomas. Unexpectedly, BCLW was overexpressed as frequently as BCL2 in follicular lymphoma. Evaluation of all five antiapoptotic BCL2 family members in six types of B-cell lymphoma revealed that BCL2, BCLW, and BCLX were consistently overexpressed, whereas MCL1 and A1 were not. In addition, individual lymphomas frequently overexpressed more than one antiapoptotic BCL2 family member.Conclusions: Our comprehensive analysis indicates B-cell lymphomas commonly select for BCLW overexpression in combination with or instead of other antiapoptotic BCL2 family members. Our results suggest BCLW may be equally as important in lymphomagenesis as BCL2 and that targeting BCLW in lymphomas should be considered. Clin Cancer Res; 23(22); 7119-29. ©2017 AACR.
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Affiliation(s)
- Clare M Adams
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ramkrishna Mitra
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jerald Z Gong
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
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14
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Chen D, Tavana O, Chu B, Erber L, Chen Y, Baer R, Gu W. NRF2 Is a Major Target of ARF in p53-Independent Tumor Suppression. Mol Cell 2017; 68:224-232.e4. [PMID: 28985506 DOI: 10.1016/j.molcel.2017.09.009] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/25/2017] [Accepted: 09/06/2017] [Indexed: 12/18/2022]
Abstract
Although ARF can suppress tumor growth by activating p53 function, the mechanisms by which it suppresses tumor growth independently of p53 are not well understood. Here, we identified ARF as a key regulator of nuclear factor E2-related factor 2 (NRF2) through complex purification. ARF inhibits the ability of NRF2 to transcriptionally activate its target genes, including SLC7A11, a component of the cystine/glutamate antiporter that regulates reactive oxygen species (ROS)-induced ferroptosis. As a consequence, ARF expression sensitizes cells to ferroptosis in a p53-independent manner while ARF depletion induces NRF2 activation and promotes cancer cell survival in response to oxidative stress. Moreover, the ability of ARF to induce p53-independent tumor growth suppression in mouse xenograft models is significantly abrogated upon NRF2 overexpression. These results demonstrate that NRF2 is a major target of p53-independent tumor suppression by ARF and also suggest that the ARF-NRF2 interaction acts as a new checkpoint for oxidative stress responses.
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Affiliation(s)
- Delin Chen
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Omid Tavana
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Bo Chu
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Luke Erber
- Departments of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yue Chen
- Departments of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Richard Baer
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Wei Gu
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA.
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15
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Abstract
Mdm2 and Mdmx are critical regulators of the p53 tumour suppressor and are overexpressed in many human malignancies. However, in recent years, their impact on genome instability was shown to be at least, in part, independent of p53. Both Mdm2 and Mdmx inhibit DNA break repair through their association with the Mre11/Rad50/Nbs1 DNA repair complex. Recent evidence indicates that harnessing Mdm2 and/or Mdmx-mediated inhibition of DNA break repair in cancer cells could provide a therapeutic opportunity, particularly for those malignancies that have lost functional p53.
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Affiliation(s)
- Christine M Eischen
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA19107, USA
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16
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Aydin Y, Chedid M, Chava S, Danielle Williams D, Liu S, Hagedorn CH, Sumitran-Holgersson S, Reiss K, Moroz K, Lu H, Balart LA, Dash S. Activation of PERK-Nrf2 oncogenic signaling promotes Mdm2-mediated Rb degradation in persistently infected HCV culture. Sci Rep 2017; 7:9223. [PMID: 28835697 PMCID: PMC5569052 DOI: 10.1038/s41598-017-10087-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/26/2017] [Indexed: 02/06/2023] Open
Abstract
The mechanism of how chronic hepatitis C virus (HCV) infection leads to such a high rate of hepatocellular carcinoma (HCC) is unknown. We found that the PERK axis of endoplasmic reticulum (ER) stress elicited prominent nuclear translocation of Nrf2 in 100% of HCV infected hepatocytes. The sustained nuclear translocation of Nrf2 in chronically infected culture induces Mdm2-mediated retinoblastoma protein (Rb) degradation. Silencing PERK and Nrf2 restored Mdm2-mediated Rb degradation, suggesting that sustained activation of PERK/Nrf2 axis creates oncogenic stress in chronically infected HCV culture model. The activation of Nrf2 and its nuclear translocation were prevented by ER-stress and PERK inhibitors, suggesting that PERK axis is involved in the sustained activation of Nrf2 signaling during chronic HCV infection. Furthermore, we show that HCV clearance induced by interferon-α based antiviral normalized the ER-stress response and prevented nuclear translocation of Nrf2, whereas HCV clearance by DAAs combination does neither. In conclusion, we report here a novel mechanism for how sustained activation of PERK axis of ER-stress during chronic HCV infection activates oncogenic Nrf2 signaling that promotes hepatocyte survival and oncogenesis by inducing Mdm2-mediated Rb degradation.
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Affiliation(s)
- Yucel Aydin
- Department of Medicine, Division of Gastroenterology and Hepatology, New Orleans, Louisiana, USA
| | - Milad Chedid
- Department of Pathology and Laboratory Medicine, New Orleans, Louisiana, USA
| | - Srinivas Chava
- Department of Pathology and Laboratory Medicine, New Orleans, Louisiana, USA
| | | | - Shuanghu Liu
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Curt H Hagedorn
- Department of Medicine and Genetics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | | | - Krzysztof Reiss
- School of Medicine, LSU Health Sciences Center, New Orleans, Louisiana, USA
| | - Krzysztof Moroz
- Department of Pathology and Laboratory Medicine, New Orleans, Louisiana, USA
| | - Hua Lu
- Department of Biochemistry, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Luis A Balart
- Department of Medicine, Division of Gastroenterology and Hepatology, New Orleans, Louisiana, USA
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, New Orleans, Louisiana, USA. .,Department of Medicine, Division of Gastroenterology and Hepatology, New Orleans, Louisiana, USA.
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17
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How gene polymorphisms can influence clinical response and toxicity following R-CHOP therapy in patients with diffuse large B cell lymphoma. Blood Rev 2017; 31:235-249. [DOI: 10.1016/j.blre.2017.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 12/07/2016] [Accepted: 02/03/2017] [Indexed: 12/20/2022]
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18
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Feeley KP, Adams CM, Mitra R, Eischen CM. Mdm2 Is Required for Survival and Growth of p53-Deficient Cancer Cells. Cancer Res 2017; 77:3823-3833. [PMID: 28576884 DOI: 10.1158/0008-5472.can-17-0809] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/15/2017] [Accepted: 05/24/2017] [Indexed: 02/06/2023]
Abstract
p53 deletion prevents the embryonic lethality of normal tissues lacking Mdm2, suggesting that cells can survive without Mdm2 if p53 is also absent. Here we report evidence challenging this view, with implications for therapeutically targeting Mdm2. Deletion of Mdm2 in T-cell lymphomas or sarcomas lacking p53 induced apoptosis and G2 cell-cycle arrest, prolonging survival of mice with these tumors. p53-/- fibroblasts showed similar results, indicating that the effects of Mdm2 loss extend to premalignant cells. Mdm2 deletion in p53-/- cells upregulated p53 transcriptional target genes that induce apoptosis and cell-cycle arrest. Mdm2 deletion also increased levels of p73, a p53 family member. RNAi-mediated attenuation of p73 rescued the transcriptional and biological effects of Mdm2 loss, indicating that p73 mediates the consequences of Mdm2 deletion. In addition, Mdm2 deletion differed from blocking Mdm2 interaction with p53 family members, as Nutlin-3 induced G1 arrest but did not activate apoptosis in p53-/- sarcoma cells. Our results indicate that, in contrast to current dogma, Mdm2 expression is required for cell survival even in the absence of p53. Moreover, our results suggest that p73 compensates for loss of p53 and that targeting Mdm2 in p53-deficient cancers has therapeutic potential. Cancer Res; 77(14); 3823-33. ©2017 AACR.
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Affiliation(s)
- Kyle P Feeley
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Clare M Adams
- Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Ramkrishna Mitra
- Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee. .,Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
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19
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Adams CM, Kim AS, Mitra R, Choi JK, Gong JZ, Eischen CM. BCL-W has a fundamental role in B cell survival and lymphomagenesis. J Clin Invest 2017; 127:635-650. [PMID: 28094768 DOI: 10.1172/jci89486] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 11/22/2016] [Indexed: 12/29/2022] Open
Abstract
Compromised apoptotic signaling is a prerequisite for tumorigenesis. The design of effective therapies for cancer treatment depends on a comprehensive understanding of the mechanisms that govern cell survival. The antiapoptotic proteins of the BCL-2 family are key regulators of cell survival and are frequently overexpressed in malignancies, leading to increased cancer cell survival. Unlike BCL-2 and BCL-XL, the closest antiapoptotic relative BCL-W is required for spermatogenesis, but was considered dispensable for all other cell types. Here, however, we have exposed a critical role for BCL-W in B cell survival and lymphomagenesis. Loss of Bcl-w conferred sensitivity to growth factor deprivation-induced B cell apoptosis. Moreover, Bcl-w loss profoundly delayed MYC-mediated B cell lymphoma development due to increased MYC-induced B cell apoptosis. We also determined that MYC regulates BCL-W expression through its transcriptional regulation of specific miR. BCL-W expression was highly selected for in patient samples of Burkitt lymphoma (BL), with 88.5% expressing BCL-W. BCL-W knockdown in BL cell lines induced apoptosis, and its overexpression conferred resistance to BCL-2 family-targeting BH3 mimetics. Additionally, BCL-W was overexpressed in diffuse large B cell lymphoma and correlated with decreased patient survival. Collectively, our results reveal that BCL-W profoundly contributes to B cell lymphoma, and its expression could serve as a biomarker for diagnosis and aid in the development of better targeted therapies.
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MESH Headings
- Animals
- Apoptosis
- Apoptosis Regulatory Proteins
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Burkitt Lymphoma/diagnosis
- Burkitt Lymphoma/genetics
- Burkitt Lymphoma/metabolism
- Burkitt Lymphoma/pathology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- Lymphoma, Large B-Cell, Diffuse/diagnosis
- Lymphoma, Large B-Cell, Diffuse/genetics
- Lymphoma, Large B-Cell, Diffuse/metabolism
- Mice
- Mice, Knockout
- Proteins/genetics
- Proteins/metabolism
- Proto-Oncogene Proteins c-myc/genetics
- Proto-Oncogene Proteins c-myc/metabolism
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20
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Carr MI, Jones SN. Regulation of the Mdm2-p53 signaling axis in the DNA damage response and tumorigenesis. Transl Cancer Res 2016; 5:707-724. [PMID: 28690977 PMCID: PMC5501481 DOI: 10.21037/tcr.2016.11.75] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The p53 tumor suppressor acts as a guardian of the genome in mammalian cells undergoing DNA double strand breaks induced by a various forms of cell stress, including inappropriate growth signals or ionizing radiation. Following damage, p53 protein levels become greatly elevated in cells and p53 functions primarily as a transcription factor to regulate the expression a wide variety of genes that coordinate this DNA damage response. In cells undergoing high amounts of DNA damage, p53 can promote apoptosis, whereas in cells undergoing less damage, p53 promotes senescence or transient cell growth arrest and the expression of genes involved in DNA repair, depending upon the cell type and level of damage. Failure of the damaged cell to undergo growth arrest or apoptosis, or to respond to the DNA damage by other p53-coordinated mechanisms, can lead to inappropriate cell growth and tumorigenesis. In cells that have successfully responded to genetic damage, the amount of p53 present in the cell must return to basal levels in order for the cell to resume normal growth and function. Although regulation of p53 levels and function is coordinated by many proteins, it is now widely accepted that the master regulator of p53 is Mdm2. In this review, we discuss the role(s) of p53 in the DNA damage response and in tumor suppression, and how post-translational modification of Mdm2 regulates the Mdm2-p53 signaling axis to govern p53 activities in the cell.
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Affiliation(s)
- Michael I Carr
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Stephen N Jones
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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21
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Fontebasso AM, Shirinian M, Khuong-Quang DA, Bechet D, Gayden T, Kool M, De Jay N, Jacob K, Gerges N, Hutter B, Şeker-Cin H, Witt H, Montpetit A, Brunet S, Lepage P, Bourret G, Klekner A, Bognár L, Hauser P, Garami M, Farmer JP, Montes JL, Atkinson J, Lambert S, Kwan T, Korshunov A, Tabori U, Collins VP, Albrecht S, Faury D, Pfister SM, Paulus W, Hasselblatt M, Jones DTW, Jabado N. Non-random aneuploidy specifies subgroups of pilocytic astrocytoma and correlates with older age. Oncotarget 2016; 6:31844-56. [PMID: 26378811 PMCID: PMC4741644 DOI: 10.18632/oncotarget.5571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 08/15/2015] [Indexed: 11/25/2022] Open
Abstract
Pilocytic astrocytoma (PA) is the most common brain tumor in children but is rare in adults, and hence poorly studied in this age group. We investigated 222 PA and report increased aneuploidy in older patients. Aneuploid genomes were identified in 45% of adult compared with 17% of pediatric PA. Gains were non-random, favoring chromosomes 5, 7, 6 and 11 in order of frequency, and preferentially affecting non-cerebellar PA and tumors with BRAF V600E mutations and not with KIAA1549-BRAF fusions or FGFR1 mutations. Aneuploid PA differentially expressed genes involved in CNS development, the unfolded protein response, and regulators of genomic stability and the cell cycle (MDM2, PLK2),whose correlated programs were overexpressed specifically in aneuploid PA compared to other glial tumors. Thus, convergence of pathways affecting the cell cycle and genomic stability may favor aneuploidy in PA, possibly representing an additional molecular driver in older patients with this brain tumor.
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Affiliation(s)
- Adam M Fontebasso
- Division of Experimental Medicine, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Margret Shirinian
- Department of Experimental Pathology, Immunology and Microbiology, American University Of Beirut, Beirut, Lebanon
| | - Dong-Anh Khuong-Quang
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Denise Bechet
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Tenzin Gayden
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Marcel Kool
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Nicolas De Jay
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Karine Jacob
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Noha Gerges
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Barbara Hutter
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Huriye Şeker-Cin
- Division of Pediatric Neurooncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Hendrik Witt
- Division of Pediatric Neurooncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany.,Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
| | - Alexandre Montpetit
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec, Canada
| | - Sébastien Brunet
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec, Canada
| | - Pierre Lepage
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec, Canada
| | - Geneviève Bourret
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec, Canada
| | - Almos Klekner
- Department of Neurosurgery, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | - László Bognár
- Department of Neurosurgery, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | - Peter Hauser
- 2nd Department of Paediatrics, Semmelweis University, Budapest, Hungary
| | - Miklós Garami
- 2nd Department of Paediatrics, Semmelweis University, Budapest, Hungary
| | - Jean-Pierre Farmer
- Department of Neurosurgery, Montreal Children's Hospital and McGill University Health Centre, Montreal, Canada
| | - Jose-Luis Montes
- Department of Neurosurgery, Montreal Children's Hospital and McGill University Health Centre, Montreal, Canada
| | - Jeffrey Atkinson
- Department of Neurosurgery, Montreal Children's Hospital and McGill University Health Centre, Montreal, Canada
| | - Sally Lambert
- Division of Molecular Histopathology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Tony Kwan
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec, Canada
| | - Andrey Korshunov
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Uri Tabori
- Division of Pediatric Hematology-Oncology and The Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada
| | - V Peter Collins
- Division of Molecular Histopathology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Steffen Albrecht
- Department of Pathology, Montreal Children's Hospital and McGill University Health Centre, Montreal, Canada
| | - Damien Faury
- Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
| | - Stefan M Pfister
- Division of Pediatric Neurooncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany.,Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
| | - Werner Paulus
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Martin Hasselblatt
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - David T W Jones
- Division of Pediatric Neurooncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Nada Jabado
- Division of Experimental Medicine, McGill University and McGill University Health Centre, Montreal, Quebec, Canada.,Departments of Pediatrics and Human Genetics, McGill University and McGill University Health Centre, Montreal, Quebec, Canada
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22
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Genome-scale functional analysis of the human genes modulating p53 activity by regulating MDM2 expression in a p53-independent manner. Biochem Biophys Res Commun 2016; 478:976-81. [PMID: 27524244 DOI: 10.1016/j.bbrc.2016.08.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 01/10/2023]
Abstract
MDM2, a critical negative regulator of p53, is often overexpressed in leukemia, but few p53 mutations are found, suggesting that p53-independent MDM2 expression occurs due to alterations in MDM2 upstream regulators. In this study, a high MDM2 transcription level was observed (41.17%) regardless of p53 expression in patient with acute myeloid leukemia (AML). Therefore, we performed genome-scale functional screening of the human genes modulating MDM2 expression in a p53-independent manner. We searched co-expression profiles of genes showing a positive or negative pattern with MDM2 expression in a DNA microarray database, selected1089 links, and composed a screening library of 368 genes. Using MDM2 P1 and P2 promoter-reporter systems, we screened clones regulating MDM2 transcriptions in a p53-independent manner by overexpression. Nine clones from the screening library showed enhanced MDM2 promoter activity and MDM2 expression in p53-deficient HCT116 cells. Among them, six clones, including NTRK2, GNA15, SFRS2, EIF5A, ELAVL1, and YWHAB mediated MAPK signaling for expressing MDM2. These results indicate that p53-independent upregulation of MDM2 by increasing selected clones may lead to oncogenesis in AML and that MDM2-modulating genes are novel potential targets for AML treatment.
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23
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Xu X, Xiong X, Sun Y. The role of ribosomal proteins in the regulation of cell proliferation, tumorigenesis, and genomic integrity. SCIENCE CHINA-LIFE SCIENCES 2016; 59:656-72. [DOI: 10.1007/s11427-016-0018-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/06/2016] [Indexed: 01/29/2023]
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Abstract
It is now clear that functional p53 is critical to protect the genome from alterations that lead to tumorigenesis. However, with the myriad of cellular stresses and pathways linked to p53 activation, much remains unknown about how p53 maintains genome stability and the proteins involved. The current understanding of the multiple ways p53 contributes to genome stability and how two of its negative regulators, Mdm2 and Mdmx, induce genome instability will be described.
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Affiliation(s)
- Christine M Eischen
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37212
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25
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Histone deacetylase inhibition reveals a tumor-suppressive function of MYC-regulated miRNA in breast and lung carcinoma. Cell Death Differ 2016; 23:1312-21. [PMID: 26915294 DOI: 10.1038/cdd.2016.9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/04/2015] [Accepted: 01/14/2016] [Indexed: 02/07/2023] Open
Abstract
Histone deacetylase (HDAC) inhibition leads to dynamic changes in the epigenetic landscape that is postulated to alter the expression of critical mediators of cellular proliferation and death. While current HDAC inhibitors have shown to be efficacious in the treatment of specific hematologic malignancies, their therapeutic utility in epithelial-based cancers warrants further evaluation. Moreover, the mechanisms of HDAC inhibition-induced cancer cell death are not completely understood. Therefore, elucidation of the underlying pathways engaged by HDAC inhibition may enable the development of more effective therapeutic strategies. Here, we report that HDAC inhibition in human breast and lung carcinoma cells activates an apoptotic mechanism mediated by microRNA (miRNA) and induced by the oncogene MYC. Specifically, following HDAC inhibition, MYC, which normally represses miR-15 and let-7 families, transcriptionally activated their expression and MYC was required for this miRNA upregulation. As a result, transcript levels of the tumor-suppressive miR-15 and let-7 families increased, which targeted and decreased the expression of the crucial prosurvival genes BCL-2 and BCL-XL, respectively. MYC was also required for the downregulation of BCL-2 and BCL-XL following HDAC inhibition. Blocking the binding sites of the miR-15 and let-7 families in the 3'-untranslated regions of BCL-2 and BCL-XL protected against HDAC inhibition-induced apoptosis. These results provide important insight into the molecular underpinnings of HDAC inhibition-induced cell death in breast and lung cancer and reveal a tumor-suppressive role for MYC-regulated miRNA that is activated with HDAC inhibition.
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26
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Gifford GK, Gill AJ, Stevenson WS. Molecular subtyping of diffuse large B-cell lymphoma: update on biology, diagnosis and emerging platforms for practising pathologists. Pathology 2016; 48:5-16. [DOI: 10.1016/j.pathol.2015.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/02/2015] [Accepted: 10/12/2015] [Indexed: 01/04/2023]
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27
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Adams CM, Hiebert SW, Eischen CM. Myc Induces miRNA-Mediated Apoptosis in Response to HDAC Inhibition in Hematologic Malignancies. Cancer Res 2015; 76:736-48. [PMID: 26676759 DOI: 10.1158/0008-5472.can-15-1751] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/12/2015] [Indexed: 12/26/2022]
Abstract
Alterations in the expression or function of histone deacetylases (HDAC) contribute to the development and progression of hematologic malignancies. Consequently, the development and implementation of HDAC inhibitors has proven to be therapeutically beneficial, particularly for hematologic malignancies. However, the molecular mechanisms by which HDAC inhibition (HDACi) induces tumor cell death remain unresolved. Here, we investigated the effects of HDACi in Myc-driven B-cell lymphoma and five other hematopoietic malignancies. We determined that Myc-mediated transcriptional repression of the miR-15 and let-7 families in malignant cells was relieved upon HDACi, and Myc was required for their upregulation. The miR-15 and let-7 families then targeted and downregulated the antiapoptotic genes Bcl-2 and Bcl-xL, respectively, to induce HDACi-mediated apoptosis. Notably, Myc also transcriptionally upregulated these miRNA in untransformed cells, indicating that this Myc-induced miRNA-mediated apoptotic pathway is suppressed in malignant cells, but becomes reactivated upon HDACi. Taken together, our results reveal a previously unknown mechanism by which Myc induces apoptosis independent of the p53 pathway and as a response to HDACi in malignant hematopoietic cells.
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Affiliation(s)
- Clare M Adams
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee.
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28
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Urso L, Calabrese F, Favaretto A, Conte P, Pasello G. Critical review about MDM2 in cancer: Possible role in malignant mesothelioma and implications for treatment. Crit Rev Oncol Hematol 2015; 97:220-30. [PMID: 26358421 DOI: 10.1016/j.critrevonc.2015.08.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 07/02/2015] [Accepted: 08/18/2015] [Indexed: 02/07/2023] Open
Abstract
The tumor suppressor p53 regulates genes involved in DNA repair, metabolism, cell cycle arrest, apoptosis and senescence. p53 is mutated in about 50% of the human cancers, while in tumors with wild-type p53 gene, the protein function may be lost because of overexpression of Murine Double Minute 2 (MDM2). MDM2 targets p53 for ubiquitylation and proteasomal degradation. p53 reactivation through MDM2 inhibitors seems to be a promising strategy to sensitize p53 wild-type cancer cells to apoptosis. Moreover, additional p53-independent molecular functions of MDM2, such as neoangiogenesis promotion, have been suggested. Thus, MDM2 might be a target for anticancer treatment because of its antiapoptotic and proangiogenetic role. Malignant pleural mesothelioma (MPM) is an aggressive asbestos-related tumor where wild-type p53 might be present. The present review gives a complete landscape about the role of MDM2 in cancer pathogenesis, prognosis and treatment, with particular focus on Malignant Pleural Mesothelioma.
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Affiliation(s)
- Loredana Urso
- Department of Surgery, Oncology and Gastroenterology, University of Padova, Italy
| | - Fiorella Calabrese
- Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Italy
| | - Adolfo Favaretto
- Medical Oncology 2, Istituto Oncologico Veneto IRCCS, Padova, Italy
| | - PierFranco Conte
- Department of Surgery, Oncology and Gastroenterology, University of Padova, Italy; Medical Oncology 2, Istituto Oncologico Veneto IRCCS, Padova, Italy
| | - Giulia Pasello
- Medical Oncology 2, Istituto Oncologico Veneto IRCCS, Padova, Italy.
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29
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Carrillo AM, Hicks M, Khabele D, Eischen CM. Pharmacologically Increasing Mdm2 Inhibits DNA Repair and Cooperates with Genotoxic Agents to Kill p53-Inactivated Ovarian Cancer Cells. Mol Cancer Res 2015; 13:1197-205. [PMID: 25964101 DOI: 10.1158/1541-7786.mcr-15-0089] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/02/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED The Mdm2 oncogene is a negative regulator of the p53 tumor suppressor and recently identified inhibitor of DNA break repair. Nutlin-3 is a small-molecule inhibitor of Mdm2-p53 interaction that can induce apoptosis in cancer cells through activation of p53. Although this is a promising therapy for those cancers with wild-type p53, half of all human cancers have inactivated p53. Here, we reveal that a previously unappreciated effect of Nutlin is inhibition of DNA break repair, stemming from its ability to increase Mdm2 protein levels. The Nutlin-induced increase in Mdm2 inhibited DNA double-strand break repair and prolonged DNA damage response signaling independent of p53. Mechanistically, this effect of Nutlin required Mdm2 and acted through Nbs1 of the Mre11-Rad50-Nbs1 DNA repair complex. In ovarian cancer cells, where >90% have inactivated p53, Nutlin combined with the genotoxic agents, cisplatin or etoposide, had a cooperative lethal effect resulting in increased DNA damage and apoptosis. Therefore, these data demonstrate an unexpected consequence of pharmacologically increasing Mdm2 levels that when used in combination with genotoxic agents induces synthetic lethality in ovarian cancer cells, and likely other malignant cell types, that have inactivated p53. IMPLICATIONS Data reveal a therapeutically beneficial effect of pharmacologically increasing Mdm2 levels combined with chemotherapeutic agents for malignancies that have lost functional p53.
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Affiliation(s)
- Alexia M Carrillo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mellissa Hicks
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dineo Khabele
- Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee.
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30
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Mdm2 overexpression and p73 loss exacerbate genomic instability and dampen apoptosis, resulting in B-cell lymphoma. Oncogene 2015; 35:358-65. [PMID: 25915849 PMCID: PMC4624041 DOI: 10.1038/onc.2015.88] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/19/2015] [Accepted: 02/25/2015] [Indexed: 11/30/2022]
Abstract
Many human tumors express high levels of the p53 inhibitor Mdm2, resulting from amplification of the Mdm2 locus or aberrant post-translational regulation of the Mdm2 protein. While the importance of Mdm2 in regulating p53 is clear, Mdm2 also has p53-independent roles. For example, overexpression of Mdm2 results in genomic instability in a p53-independent manner. In addition, Mdm2 has many additional binding partners; some such as the tumor suppressor p73 have also been implicated in genomic instability. In this study, cells and tumors with Mdm2 overexpression and p73 loss exhibit increased genomic instability as compared to either alteration alone and cooperate in development of B-cell lymphomagenesis. Cytogenetic analyses of mouse embryonic fibroblasts and pre-malignant B-cells demonstrate that loss of p73 exacerbates the chromosome breaks and fusions observed in Mdm2Tg cells. B-cell lymphomas from Mdm2Tg;p73+/− mice retain the remaining p73 allele, and exhibit elevated levels of the anti-apoptotic protein Bcl2 and thus dampen apoptosis. In summary, Mdm2 overexpression and p73 loss cooperate in genomic instability and tumor development, indicating that the oncogenic functions of Mdm2 are a combined effect of inhibiting p53 and p73 functions. Given that p73 is lost or silenced in human B-cell lymphomas [1–4], the Mdm2Tg;p73+/− mouse serves as a model for human disease and may provide additional insight into the pathways that contribute to B-cell lymphomagenesis.
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31
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Kim TH, Leslie P, Zhang Y. Ribosomal proteins as unrevealed caretakers for cellular stress and genomic instability. Oncotarget 2015; 5:860-71. [PMID: 24658219 PMCID: PMC4011588 DOI: 10.18632/oncotarget.1784] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Ribosomal proteins (RPs) have gained much attention for their extraribosomal functions particularly with respect to p53 regulation. To date, about fourteen RPs have shown to bind to MDM2 and regulate p53. Upon binding to MDM2, the RPs suppress MDM2 E3 ubiquitin ligase activity resulting in the stabilization and activation of p53. Of the RPs that bind to MDM2, RPL5 and RPL11 are the most studied and RPL11 appears to have the most significant role in p53 regulation. Considering that more than 17% of RP species have been shown to interact with MDM2, one of the questions remains unresolved is why so many RPs bind MDM2 and modulate p53. Genes encoding RPs are widely dispersed on different chromosomes in both mice and humans. As components of ribosome, RP expression is tightly regulated to meet the appropriate stoichiometric ratio between RPs and rRNAs. Once genomic instability (e.g. aneuploidy) occurs, transcriptional and translational changes due to change of DNA copy number can result in an imbalance in the expression of RPs including those that bind to MDM2. Such an imbalance in RP expression could lead to failure to assemble functional ribosomes resulting in ribosomal stress. We propose that RPs have evolved ability to regulate MDM2 in response to genomic instability as an additional layer of p53 regulation. Full understanding of the biological roles of RPs could potentially establish RPs as a novel class of therapeutic targets in human diseases such as cancer.
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Affiliation(s)
- Tae-Hyung Kim
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC, USA
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32
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Carrillo AM, Bouska A, Arrate MP, Eischen CM. Mdmx promotes genomic instability independent of p53 and Mdm2. Oncogene 2015; 34:846-56. [PMID: 24608433 PMCID: PMC4160436 DOI: 10.1038/onc.2014.27] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 12/02/2013] [Accepted: 12/18/2013] [Indexed: 12/26/2022]
Abstract
The oncogene Mdmx is overexpressed in many human malignancies, and together with Mdm2, negatively regulates the p53 tumor suppressor. However, a p53-independent function of Mdmx that impacts genome stability has been described, but this function is not well understood. In the present study, we determined that of the 13 different cancer types evaluated, 6-90% of those that had elevated levels of Mdmx had concurrent inactivation (mutated or deleted) of p53. We show elevated levels of Mdmx-inhibited double-strand DNA break repair and induced chromosome and chromatid breaks independent of p53, leading to genome instability. Mdmx impaired early DNA damage-response signaling, such as phosphorylation of the serine/threonine-glutamine motif, mediated by the ATM kinase. Moreover, we identified Mdmx associated with Nbs1 of the Mre11-Rad50-Nbs1 (MRN) DNA repair complex, and this association increased upon DNA damage and was detected at chromatin. Elevated Mdmx levels also increased cellular transformation in a p53-independent manner. Unexpectedly, all Mdmx-mediated phenotypes also occurred in cells lacking Mdm2 and were independent of the Mdm2-binding domain (RING) of Mdmx. Therefore, Mdmx-mediated inhibition of the DNA damage response resulted in delayed DNA repair and increased genome instability and transformation independent of p53 and Mdm2. Our results reveal a novel p53- and Mdm2-independent oncogenic function of Mdmx that provides new insight into the many cancers that overexpress Mdmx.
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Affiliation(s)
- Alexia M. Carrillo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - Alyssa Bouska
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
| | - Maria Pia Arrate
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - Christine M. Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
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Mitra R, Edmonds MD, Sun J, Zhao M, Yu H, Eischen CM, Zhao Z. Reproducible combinatorial regulatory networks elucidate novel oncogenic microRNAs in non-small cell lung cancer. RNA (NEW YORK, N.Y.) 2014; 20:1356-68. [PMID: 25024357 PMCID: PMC4138319 DOI: 10.1261/rna.042754.113] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 05/01/2014] [Indexed: 06/03/2023]
Abstract
While previous studies reported aberrant expression of microRNAs (miRNAs) in non-small cell lung cancer (NSCLC), little is known about which miRNAs play central roles in NSCLC's pathogenesis and its regulatory mechanisms. To address this issue, we presented a robust computational framework that integrated matched miRNA and mRNA expression profiles in NSCLC using feed-forward loops. The network consists of miRNAs, transcription factors (TFs), and their common predicted target genes. To discern the biological meaning of their associations, we introduced the direction of regulation. A network edge validation strategy using three independent NSCLC expression profiling data sets pinpointed reproducible biological regulations. Reproducible regulation, which may reflect the true molecular interaction, has not been applied to miRNA-TF co-regulatory network analyses in cancer or other diseases yet. We revealed eight hub miRNAs that connected to a higher proportion of targets validated by independent data sets. Network analyses showed that these miRNAs might have strong oncogenic characteristics. Furthermore, we identified a novel miRNA-TF co-regulatory module that potentially suppresses the tumor suppressor activity of the TGF-β pathway by targeting a core pathway molecule (TGFBR2). Follow-up experiments showed two miRNAs (miR-9-5p and miR-130b-3p) in this module had increased expression while their target gene TGFBR2 had decreased expression in a cohort of human NSCLC. Moreover, we demonstrated these two miRNAs directly bind to the 3' untranslated region of TGFBR2. This study enhanced our understanding of miRNA-TF co-regulatory mechanisms in NSCLC. The combined bioinformatics and validation approach we described can be applied to study other types of diseases.
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Affiliation(s)
- Ramkrishna Mitra
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Mick D Edmonds
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Jingchun Sun
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Min Zhao
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Hui Yu
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Zhongming Zhao
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee 37212, USA Center for Quantitative Sciences, Vanderbilt University, Nashville, Tennessee 37232, USA
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34
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Adams CM, Eischen CM. Inactivation of p53 is insufficient to allow B cells and B-cell lymphomas to survive without Dicer. Cancer Res 2014; 74:3923-34. [PMID: 24840646 DOI: 10.1158/0008-5472.can-13-1866] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inactivation of p53, the master regulator of cellular stress and damage signals, often allows cells that should die or senesce to live. Loss of Dicer, an RNase III-like enzyme critical in microRNA biogenesis, causes embryonic lethality and activation of the p53 pathway. Several nonhematopoietic cell types that contain inactivated p53 have been shown to survive Dicer deletion, suggesting that p53 loss may protect cells from the negative consequences of Dicer deletion. However, here, we report that loss of p53 did not provide a survival advantage to B cells, as they underwent rapid apoptosis upon Dicer deletion. Moreover, a deficiency in p53 neither rescued the Dicer deletion-induced delay in Myc-driven B-cell lymphomagenesis, nor allowed a single B-cell lymphoma to develop with biallelic deletion of Dicer. A p53 deficiency did, however, restore the pre-B/B-cell phenotype and CD19 surface expression of the lymphomas that emerged in conditional Dicer knockout Eμ-myc transgenic mice. Moreover, p53 loss in transformed B cells did not confer protection from apoptosis, as Dicer deletion in established p53-null B-cell lymphomas induced apoptosis, and all of the 1,260 B-cell lymphoma clones analyzed that survived Cre-mediated Dicer deletion retained at least one allele of Dicer. Moreover, Dicer deletion in lymphomas in vivo reduced tumor burden and prolonged survival. Therefore, inactivation of p53 is insufficient to allow untransformed B cells and B-cell lymphomas to survive without Dicer, presenting a potential therapeutic opportunity for the treatment of B-cell lymphomas.
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Affiliation(s)
- Clare M Adams
- Authors' Affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Christine M Eischen
- Authors' Affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
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Eischen CM, Lozano G. The Mdm network and its regulation of p53 activities: a rheostat of cancer risk. Hum Mutat 2014; 35:728-37. [PMID: 24488925 DOI: 10.1002/humu.22524] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/31/2014] [Indexed: 11/07/2022]
Abstract
The potent transcriptional activity of p53 (Trp53, TP53) must be kept in check for normal cell growth and survival. Tumors, which drastically deviate from these parameters, have evolved multiple mechanisms to inactivate TP53, the most prevalent of which is the emergence of TP53 missense mutations, some of which have gain-of-function activities. Another important mechanism by which tumors bypass TP53 functions is via increased levels of two TP53 inhibitors, MDM2, and MDM4. Studies in humans and in mice reveal the complexity of TP53 regulation and the exquisite sensitivity of this pathway to small changes in regulation. Here, we summarize the factors that impinge on TP53 activity and thus cell death/arrest or tumor development.
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Affiliation(s)
- Christine M Eischen
- Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, Nashville, Tennessee
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Abstract
Mdm2 is best known as the primary negative regulator of p53, but a growing body of evidence suggests that Mdm2 also has a number of functions independent of its role in regulating p53. Although these functions are not yet well-characterized, they have been implicated in regulating of a number of cellular processes, including cell-cycle control, apoptosis, differentiation, genome stability, and transcription, among others. It appears that Mdm2 exerts these functions through a surprisingly wide variety of mechanisms. For example, it has been shown that Mdm2 can ubiquitinate alternative targets, can stimulate the activity of transcription factors, and can directly bind to mRNA to regulate its stability. Dysregulation of p53-independent functions could be responsible for the oncogenic properties of Mdm2 seen even in the absence of p53, and may explain why approximately 10 % of human tumors overexpress Mdm2 instead of inactivating p53 through other mechanisms. As the p53-independent functions of Mdm2 present novel targets for potential therapeutic interventions, fully characterizing these cellular and pathogenic roles of Mdm2 will be important in the study of tumor biology and the treatment of cancer.
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miR-223 regulates cell growth and targets proto-oncogenes in mycosis fungoides/cutaneous T-cell lymphoma. J Invest Dermatol 2013; 134:1101-1107. [PMID: 24304814 PMCID: PMC3961555 DOI: 10.1038/jid.2013.461] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 12/16/2022]
Abstract
The pathogenesis of the cutaneous T-cell lymphoma (CTCL), mycosis fungoides (MF) is unclear. MicroRNA (miRNA) are small non-coding RNA that target mRNA leading to reduced mRNA translation. Recently, specific miRNA were shown to be altered in CTCL. We identified significantly reduced expression of miR-223 in early stage MF skin, and the levels of miR-223 diminished further in advanced stage disease. CTCL peripheral blood mononuclear cells and cell lines also had reduced miR-223 as compared to controls. Elevated expression of miR-223 in these cell lines reduced cell growth and clonogenic potential, whereas inhibition of miR-223 increased cell numbers. Investigations into putative miR-223 targets with oncogenic function, including E2F1 and MEF2C, and the predicted miR-223 target, TOX, revealed all three are targeted by miR-223 in CTCL. E2F1, MEF2C, and TOX proteins were decreased with miR-223 overexpression, while miR-223 inhibition led to increased protein levels in CTCL. In addition, we showed the 3′-UTR of TOX mRNA was a genuine target of miR-223. Therefore, reduced levels of miR-223 in MF/CTCL lead to increased expression of E2F1, MEF2C, and TOX, which likely contribute to the development and/or progression of CTCL. Thus, miR-223 and its targets may be useful for the development of new therapeutics for MF/CTCL.
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MDM2 phenotypic and genotypic profiling, respective to TP53 genetic status, in diffuse large B-cell lymphoma patients treated with rituximab-CHOP immunochemotherapy: a report from the International DLBCL Rituximab-CHOP Consortium Program. Blood 2013; 122:2630-40. [PMID: 23982177 DOI: 10.1182/blood-2012-12-473702] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
MDM2 is a key negative regulator of the tumor suppressor p53, however, the prognostic significance of MDM2 overexpression in diffuse large B-cell lymphoma (DLBCL) has not been defined convincingly. In a p53 genetically-defined large cohort of de novo DLBCL patients treated with rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone (R-CHOP) chemotherapy, we assessed MDM2 and p53 expression by immunohistochemistry (n = 478), MDM2 gene amplification by fluorescence in situ hybridization (n = 364), and a single nucleotide polymorphism in the MDM2 promoter, SNP309, by SNP genotyping assay (n = 108). Our results show that MDM2 overexpression, unlike p53 overexpression, is not a significant prognostic factor in overall DLBCL. Both MDM2 and p53 overexpression do not predict for an adverse clinical outcome in patients with wild-type p53 but predicts for significantly poorer survival in patients with mutated p53. Variable p53 activities may ultimately determine the survival differences, as suggested by the gene expression profiling analysis. MDM2 amplification was observed in 3 of 364 (0.8%) patients with high MDM2 expression. The presence of SNP309 did not correlate with MDM2 expression and survival. This study indicates that evaluation of MDM2 and p53 expression correlating with TP53 genetic status is essential to assess their prognostic significance and is important for designing therapeutic strategies that target the MDM2-p53 interaction.
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Rao CV, Yamada HY. Genomic instability and colon carcinogenesis: from the perspective of genes. Front Oncol 2013; 3:130. [PMID: 23734346 PMCID: PMC3659308 DOI: 10.3389/fonc.2013.00130] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/07/2013] [Indexed: 12/12/2022] Open
Abstract
Colon cancer is the second most lethal cancer; approximately 600,000 people die of it annually in the world. Colon carcinogenesis generally follows a slow and stepwise process of accumulation of mutations under the influence of environmental and epigenetic factors. To adopt a personalized (tailored) cancer therapy approach and to improve current strategies for prevention, diagnosis, prognosis, and therapy overall, advanced understanding of molecular events associated with colon carcinogenesis is necessary. A contemporary approach that combines genetics, epigenomics, and signaling pathways has revealed many genetic/genomic alterations associated with colon cancer progression and their relationships to a genomic instability phenotype prevalent in colon cancer. In this review, we describe the relationship between gene mutations associated with colon carcinogenesis and a genomic instability phenotype, and we discuss possible clinical applications of genomic instability studies. Colon carcinogenesis is associated with frequent mutations in several pathways that include phosphatidylinositol 3-kinase, adenomatous polyposis coli, p53 (TP53), F-box and WD repeat domain containing 7, transforming growth factor-β, chromosome cohesion, and K-RAS. These genes frequently mutated in pathways affecting colon cancer were designated colon cancer (CAN) genes. Aberrations in major colon CAN genes have a causal relationship to genomic instability. Conversely, genomic instability itself plays a role in colon carcinogenesis in experimental settings, as demonstrated in transgenic mouse models with high genomic instability. Thus, there is a feedback-type relationship between CAN gene mutations and genomic instability. These genetic/genomic studies have led to emerging efforts to apply the knowledge to colon cancer prognosis and to targeted therapy.
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Affiliation(s)
- Chinthalapally V Rao
- Department of Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
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Abstract
The MDM2 and MDMX (also known as HDMX and MDM4) proteins are deregulated in many human cancers and exert their oncogenic activity predominantly by inhibiting the p53 tumour suppressor. However, the MDM proteins modulate and respond to many other signalling networks in which they are embedded. Recent mechanistic studies and animal models have demonstrated how functional interactions in these networks are crucial for maintaining normal tissue homeostasis, and for determining responses to oncogenic and therapeutic challenges. This Review highlights the progress made and pitfalls encountered as the field continues to search for MDM-targeted antitumour agents.
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Affiliation(s)
- Mark Wade
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Via Adamello 16, 20139 Milan, Italy
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41
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Abstract
The contribution of Mdm2, and its recently identified family member Mdmx (Mdm4), to tumorigenesis has primarily focused on their negative regulation of the p53 tumor suppressor. Although Mdm2 and Mdmx clearly inhibit p53, which can lead to tumor development, both have also been shown to affect tumorigenesis independent of p53. Given that Mdm2 and/or Mdmx overexpression is common and likely underestimated in human cancers, understanding the functions of these proteins beyond p53 control is critical. In recent years, new functions of Mdm2 and Mdmx that lead to genome instability, a hallmark of malignancy, have emerged. Specifically, roles in the DNA damage response that are distinct from their regulation of p53 have been identified. Inhibition of p53 as well as other components of the DNA damage response by Mdm2 and Mdmx can result in delayed DNA repair and increased genome instability, making Mdm2 and Mdmx a danger to the genome when aberrantly expressed. However, the genome instability caused by altered levels of Mdm2 and Mdmx could be used therapeutically for the treatment of cancer. Specifically, drugs/small molecules that target the interaction between Mdm2 and p53 can stabilize Mdm2, resulting in negative consequences on the genome that could be exploited for cancer treatment, particularly malignancies lacking functional p53.
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Affiliation(s)
- Alexia N Melo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
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Abstract
Cancer cells often have high expression of Mdm2. However, in many cancers mdm2 is alternatively spliced, with more than 40 mRNA variants identified. Many of the alternative spliced mdm2 mRNAs have the potential to encode truncated Mdm2 isoforms. These putative Mdm2 isoforms can theoretically increase the diversity of the cancer proteome. The 3 best characterized are Mdm2-A, Mdm2-B, and Mdm2-C. As described in this review, the exogenous expression of these isoforms results in paradoxical phenotypes of transformation-associated growth as well as the inhibition of growth. Interestingly, these Mdm2 isoforms contribute tumor-promoting capacity in p53-null backgrounds. Herein we describe how alternative splicing of mdm2 may result in Mdm2 protein products that alter signal transduction to promote tumorigenesis. The tumor promoting capacity of Mdm2 isoforms is discussed in the context of functions that do not require the inhibition of p53. When N-terminal portions of Mdm2 are missing, the biochemical functions encoded by exon 12 are proposed to become more important. This may result in growth promoting functions when wild-type p53 is absent or compromised. The p53-independent tumor promoting activity of Mdm2 is proposed to result from C-terminal biochemical contributions of DNA binding, RNA binding, nucleolar localization, and nucleotide binding.
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Affiliation(s)
- Danielle R Okoro
- The City University of New York at Hunter College and the Graduate Center, New York, NY, USA
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Love IM, Grossman SR. It Takes 15 to Tango: Making Sense of the Many Ubiquitin Ligases of p53. Genes Cancer 2012; 3:249-63. [PMID: 23150758 DOI: 10.1177/1947601912455198] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The transcription factor p53 regulates numerous cellular processes to guard against tumorigenesis. Cell-cycle inhibition, apoptosis, and autophagy are all regulated by p53 in a cell- and context-specific manner, underscoring the need for p53 activity to be kept low in most circumstances. p53 is kept in check primarily through its regulated ubiquitination and degradation by a number of different factors, whose contributions may reflect complex context-specific needs to restrain p53 activity. Chief among these E3 ubiquitin ligases in p53 homeostasis is the ubiquitously expressed proto-oncogene MDM2, whose loss renders vertebrates unable to limit p53 activity, resulting in early embryonic lethality. MDM2 has been validated as a critical, universal E3 ubiquitin ligase for p53 in numerous tissues and organisms to date, but additional E3 ligases have also been identified for p53 whose contribution to p53 activity is unclear. In this review, we summarize the recent advances in our knowledge regarding how p53 activity is apparently controlled by a multitude of ubiquitin ligases beyond MDM2.
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Affiliation(s)
- Ian M Love
- Division of Hematology, Oncology, and Palliative Care, Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
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Monti S, Chapuy B, Takeyama K, Rodig SJ, Hao Y, Yeda KT, Inguilizian H, Mermel C, Curie T, Dogan A, Kutok JL, Beroukim R, Neuberg D, Habermann T, Getz G, Kung AL, Golub TR, Shipp MA. Integrative analysis reveals an outcome-associated and targetable pattern of p53 and cell cycle deregulation in diffuse large B cell lymphoma. Cancer Cell 2012; 22:359-72. [PMID: 22975378 PMCID: PMC3778921 DOI: 10.1016/j.ccr.2012.07.014] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 04/19/2012] [Accepted: 07/24/2012] [Indexed: 11/20/2022]
Abstract
Diffuse large B cell lymphoma (DLBCL) is a clinically and biologically heterogeneous disease with a high proliferation rate. By integrating copy number data with transcriptional profiles and performing pathway analysis in primary DLBCLs, we identified a comprehensive set of copy number alterations (CNAs) that decreased p53 activity and perturbed cell cycle regulation. Primary tumors either had multiple complementary alterations of p53 and cell cycle components or largely lacked these lesions. DLBCLs with p53 and cell cycle pathway CNAs had decreased abundance of p53 target transcripts and increased expression of E2F target genes and the Ki67 proliferation marker. CNAs of the CDKN2A-TP53-RB-E2F axis provide a structural basis for increased proliferation in DLBCL, predict outcome with current therapy, and suggest targeted treatment approaches.
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Affiliation(s)
| | - Bjoern Chapuy
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Kunihiko Takeyama
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Scott J Rodig
- Department of Pathology, Brigham & Women’s Hospital, Boston, MA
| | - Yangsheng Hao
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Kelly T. Yeda
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Haig Inguilizian
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
| | | | - Treeve Curie
- Department of Pathology, Brigham & Women’s Hospital, Boston, MA
| | - Ahmed Dogan
- Department of Laboratory Medicine and Pathology, College of Medicine, Mayo Clinic, Rochester, MN
| | - Jeffery L Kutok
- Department of Pathology, Brigham & Women’s Hospital, Boston, MA
| | | | - Donna Neuberg
- Department of Biostatistics, Dana-Farber Cancer Institute, Boston, MA
| | - Thomas Habermann
- Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN
| | - Gad Getz
- Cancer Program, Broad Institute, Cambridge, MA
| | - Andrew L Kung
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
| | | | - Margaret A Shipp
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
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Abstract
Mdm2 is an essential regulator of the p53 tumor suppressor. Mdm2 is modified at transcriptional, post-transcriptional, and post-translational levels to control p53 activity in normal versus stressed cells. Importantly, errors in these regulatory mechanisms can result in aberrant Mdm2 expression and failure to initiate programmed cell death in response to DNA damage. Such errors can have severe consequences as evidenced by tumor phenotypes resulting from amplification at the Mdm2 locus and changes in post-transcriptional and post-translational regulation of Mdm2. Although Mdm2 mediated inhibition of p53 is well characterized, Mdm2 interacts with many additional proteins and also targets many of these for proteosomal degradation. Mdm2 also has E3-ligase independent functions and p53-independent functions that have important implications for genome stability and cancer.
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Affiliation(s)
- Maurisa F Riley
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
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46
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Suppression of Ras/Mapk pathway signaling inhibits Myc-induced lymphomagenesis. Cell Death Differ 2012; 19:1220-7. [PMID: 22301919 DOI: 10.1038/cdd.2012.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Although the Myc transcription factor has been shown necessary for the oncogenic function of Ras, the contribution of Ras pathway signaling to the oncogenic function of Myc remains unresolved. We report the novel findings that Myc alone induced Ras/Mapk pathway signaling, and increased signaling following growth factor stimulation. Deletion of the scaffold protein kinase suppressor of Ras 1 (Ksr1) attenuated signaling through the Ras/Mapk pathway, including activation following Myc induction. B cells that lacked Ksr1 exhibited reduced proliferation and increased cytokine deprivation-induced apoptosis. Overexpression of Myc rescued the proliferation defect of Ksr1-null B cells, but loss of Ksr1 increased sensitivity of B cells to Myc-induced apoptosis. Notably, there was a significant delay in lymphoma development in Ksr1-null mice overexpressing Myc in B cells (Eμ-myc transgenic mice). There was an elevated frequency of p53 inactivation, indicative of increased selective pressure to bypass the p53 tumor suppressor pathway, in Ksr1-null Eμ-myc lymphomas. Therefore, loss of Ksr1 inhibits Ras/Mapk pathway signaling leading to increased Myc-induced B-cell apoptosis, and this results in reduced B-cell transformation and lymphoma development. Our data indicate that suppression of Myc-induced Ras/Mapk pathway signaling significantly impairs Myc oncogenic function. These results fill a significant gap in knowledge about Myc and should open new avenues of therapeutic intervention for Myc-overexpressing malignancies.
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Abstract
Aging is thought to negatively affect multiple cellular processes including the ability to maintain chromosome stability. Chromosome instability (CIN) is a common property of cancer cells and may be a contributing factor to cellular transformation. The types of DNA aberrations that arise during aging before tumor development and that contribute to tumorigenesis are currently unclear. Mdm2, a key regulator of the p53 tumor suppressor and modulator of DNA break repair, is frequently overexpressed in malignancies and contributes to CIN. To determine the relationship between aging and CIN and the role of Mdm2, precancerous wild-type C57Bl/6 and littermate-matched Mdm2 transgenic mice at various ages were evaluated. Metaphase analyses of wild-type cells showed a direct correlation between age and increased chromosome and chromatid breaks, chromosome fusions and aneuploidy, but the frequency of polyploidy remained stable over time. Elevated levels of Mdm2 in precancerous mice increased both the numerical and the structural chromosomal abnormalities observed. Chromosome and chromatid breaks, chromosome fusions, aneuploidy and polyploidy were increased in older Mdm2 transgenic mice compared with wild-type littermates. Unexpectedly, chromosome fusions, aneuploidy and polyploidy rates in Mdm2 transgenic mice, but not chromosome and chromatid breaks, showed cooperation between Mdm2 overexpression and age. Notably, Mdm2 overexpression promoted gains in one or more chromosomes with age, while it did not affect the rate of chromosome loss. Therefore, aging increased specific forms of genomic instability, and elevated Mdm2 expression cooperated with aging to increase the likelihood of gaining certain chromosomal abnormalities of the kind thought to lead to cancer development.
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Camacho FI, Bellas C, Corbacho C, Caleo A, Arranz-Sáez R, Cannata J, Menárguez J, Sánchez-Verde L, González-Camacho L, Pérez-Martín ME, Martínez-González MA, Alvaro T, Mollejo M, Ruíz-Marcellán C, Montalbán C, Piris MA. Improved demonstration of immunohistochemical prognostic markers for survival in follicular lymphoma cells. Mod Pathol 2011; 24:698-707. [PMID: 21240256 DOI: 10.1038/modpathol.2010.237] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Follicular lymphoma (FL) is one of the most common forms of the low-grade non-Hodgkin's lymphoma in adults, with a characteristic translocation, t(14;18)(q32;q21) that deregulates the expression of the BCL2 gene. The clinical course of FL patients is variable, whereby a subset of patients survive for long periods even without relapses, whereas the majority have frequent relapses with shorter survival. We have analyzed a series of 186 FLs, studying the correlation between clinical outcome and the tumor cell expression of a set of immunohistochemical markers, using an automated procedure for tissue microarrays to reduce the subjectivity of scoring. The results identified several markers associated with differences in overall survival (OS) in univariate analyses, such as Cyclin E, Mdm2, CD10, p21, IgD, Bcl-xL, CD30, and E2F6. Cases with a higher level of expression of Cyclin E, Mdm2, p21, IgD, Bcl-xL, CD30, and E2F6 were associated with a significantly shorter OS. On the other hand, strong CD10 expression was linked to a significantly better outcome. A Cox model was then constructed, integrating the Follicular Lymphoma International Prognostic Index (FLIPI) score and a restricted selection of three immunohistochemical markers: Cyclin E, Mdm2, and CD10 expression. A potentially useful finding is that the integrated FLIPI plus immunohistochemical model can be used to identify a subset of 26 patients (almost 20% of the total series), with a survival probability of 100% at 5 years. This not only confirms that a group of FL cases may have a very good clinical course, but also indicates that this group can be identified using this integrated clinical and immunohistochemical approach.
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Affiliation(s)
- Francisca I Camacho
- Department of Pathology, Hospital Universitario de Getafe, Carretera de Toledo, Getafe, Madrid, Spain.
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Abstract
Most solid tumors are aneuploid, having a chromosome number that is not a multiple of the haploid number, and many frequently mis-segregate whole chromosomes in a phenomenon called chromosomal instability (CIN). CIN positively correlates with poor patient prognosis, indicating that reduced mitotic fidelity contributes to cancer progression by increasing genetic diversity among tumor cells. Here, we review the mechanisms underlying CIN, which include defects in chromosome cohesion, mitotic checkpoint function, centrosome copy number, kinetochore-microtubule attachment dynamics, and cell-cycle regulation. Understanding these mechanisms provides insight into the cellular consequences of CIN and reveals the possibility of exploiting CIN in cancer therapy.
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50
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Arrate MP, Vincent T, Odvody J, Kar R, Jones SN, Eischen CM. MicroRNA biogenesis is required for Myc-induced B-cell lymphoma development and survival. Cancer Res 2010; 70:6083-92. [PMID: 20587524 DOI: 10.1158/0008-5472.can-09-4736] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Many tumor cells express globally reduced levels of microRNAs (miRNA), suggesting that decreased miRNA expression in premalignant cells contributes to their tumorigenic phenotype. In support of this, Dicer, an RNase III-like enzyme that controls the maturation of miRNA, was recently shown to function as a haploinsufficient tumor suppressor in nonhematopoietic cells. Because the Myc oncoprotein, a critical inducer of B-cell lymphomas, was reported to suppress the expression of multiple miRNAs in lymphoma cells, it was presumed that a deficiency of Dicer and subsequent loss of miRNA maturation would accelerate Myc-induced lymphoma development. We report here that, surprisingly, a haploinsufficiency of Dicer in B cells failed to promote B-cell malignancy or accelerate Myc-induced B-cell lymphomagenesis in mice. Moreover, deletion of Dicer in B cells of CD19-cre(+)/Emicro-myc mice significantly inhibited lymphomagenesis, and all lymphomas that did arise in these mice lacked functional Cre expression and retained at least one functional Dicer allele. Uncharacteristically, the lymphomas that frequently developed in the CD19-cre(+)/Dicer(fl/fl)/Emicro-myc mice were of very early precursor B-cell origin, a stage of B-cell development prior to Cre expression. Therefore, loss of Dicer function was not advantageous for lymphomagenesis, but rather, Dicer ablation was strongly selected against during Myc-induced B-cell lymphoma development. Moreover, deletion of Dicer in established B-cell lymphomas resulted in apoptosis, revealing that Dicer is required for B-cell lymphoma survival. Thus, Dicer does not function as a haploinsufficient tumor suppressor in B cells and is required for B-cell lymphoma development and survival.
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Affiliation(s)
- Maria Pia Arrate
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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