301
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Abdullah A, Sane S, Freeling JL, Wang H, Zhang D, Rezvani K. Nucleocytoplasmic Translocation of UBXN2A Is Required for Apoptosis during DNA Damage Stresses in Colon Cancer Cells. J Cancer 2015; 6:1066-78. [PMID: 26516353 PMCID: PMC4615341 DOI: 10.7150/jca.12134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 08/02/2015] [Indexed: 12/12/2022] Open
Abstract
The subcellular localization, expression level, and activity of anti-cancer proteins alter in response to intrinsic and extrinsic cellular stresses to reverse tumor progression. The purpose of this study is to determine whether UBXN2A, an activator of the p53 tumor suppressor protein, has different subcellular compartmentalization in response to the stress of DNA damage. We measured trafficking of the UBXN2A protein in response to two different DNA damage stresses, UVB irradiation and the genotoxic agent Etoposide, in colon cancer cell lines. Using a cytosol-nuclear fractionation technique followed by western blot and immunofluorescence staining, we monitored and quantitated UBXN2A and p53 proteins as well as p53's downstream apoptotic pathway. We showed that the anti-cancer protein UBXN2A acts in the early phase of cell response to two different DNA damage stresses, being induced to translocate into the cytoplasm in a dose- and time-dependent manner. UVB-induced cytoplasmic UBXN2A binds to mortalin-2 (mot-2), a known oncoprotein in colon tumors. UVB-dependent upregulation of UBXN2A in the cytoplasm decreases p53 binding to mot-2 and activates apoptotic events in colon cancer cells. In contrast, the shRNA-mediated depletion of UBXN2A leads to significant reduction in apoptosis in colon cancer cells exposed to UVB and Etoposide. Leptomycin B (LMB), which was able to block UBXN2A nuclear export following Etoposide treatment, sustained p53-mot-2 interaction and had partially antagonistic effects with Etoposide on cell apoptosis. The present study shows that nucleocytoplasmic translocation of UBXN2A in response to stresses is necessary for its anti-cancer function in the cytoplasm. In addition, LMB-dependent suppression of UBXN2A's translocation to the cytoplasm upon stress allows the presence of an active mot-2 oncoprotein in the cytoplasm, resulting in p53 sequestration as well as activation of other mot-2-dependent growth promoting pathways.
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Affiliation(s)
- Ammara Abdullah
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Sanam Sane
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Jessica L Freeling
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Hongmin Wang
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Dong Zhang
- 2. Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Northern Blvd., P.O. Box 8000, Old Westbury, NY 11568-8000, USA
| | - Khosrow Rezvani
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
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302
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Bauer NC, Doetsch PW, Corbett AH. Mechanisms Regulating Protein Localization. Traffic 2015; 16:1039-61. [PMID: 26172624 DOI: 10.1111/tra.12310] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 12/23/2022]
Abstract
Cellular functions are dictated by protein content and activity. There are numerous strategies to regulate proteins varying from modulating gene expression to post-translational modifications. One commonly used mode of regulation in eukaryotes is targeted localization. By specifically redirecting the localization of a pool of existing protein, cells can achieve rapid changes in local protein function. Eukaryotic cells have evolved elegant targeting pathways to direct proteins to the appropriate cellular location or locations. Here, we provide a general overview of these localization pathways, with a focus on nuclear and mitochondrial transport, and present a survey of the evolutionarily conserved regulatory strategies identified thus far. We end with a description of several specific examples of proteins that exploit localization as an important mode of regulation.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Current address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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303
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Ke JY, Dai CJ, Wu WL, Gao JH, Xia AJ, Liu GP, Lv KS, Wu CL. USP11 regulates p53 stability by deubiquitinating p53. J Zhejiang Univ Sci B 2015; 15:1032-8. [PMID: 25471832 DOI: 10.1631/jzus.b1400180] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppressor function, which is tightly controlled by ubiquitin-dependent degradation primarily through its negative regulator murine double minute 2 (Mdm2). To better understand the regulation of p53, we tested the interaction between p53 and USP11 using co-immunoprecipitation. The results show that USP11, an ubiquitin-specific protease, forms specific complexes with p53 and stabilizes p53 by deubiquitinating it. Moreover, down-regulation of USP11 dramatically attenuated p53 induction in response to DNA damage stress. These findings reveal that USP11 is a novel regulator of p53, which is required for p53 activation in response to DNA damage.
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Affiliation(s)
- Jia-ying Ke
- College of Chemistry and Life Science, Quanzhou Normal University, Quanzhou 36200, China; The Higher Educational Key Laboratory for Molecular Biology and Pharmacology of Fujian Province, Quanzhou 36200, China; Xiamen Women and Children Health Hospital, Xiamen 361005, China; Shouguang People's Hospital, Shouguang 262700, China; Department of Orthopedics, Central Hospital of Zibo, Zibo 255000, China; Department of Pathology, University of Chicago, Chicago 60102, Illinois, USA; Department of Pathology, the Second Affiliated Hospital of Fujian Medical University, Quanzhou 36200, China
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304
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Pal A, Donato NJ. Ubiquitin-specific proteases as therapeutic targets for the treatment of breast cancer. Breast Cancer Res 2015; 16:461. [PMID: 25606592 PMCID: PMC4384352 DOI: 10.1186/s13058-014-0461-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Key mediators of signaling pathways in breast cancer involve post-translational protein modification, primarily mediated through phosphorylation and ubiquitination. While previous studies focused on phosphorylation events, more recent analysis suggests that ubiquitin plays a parallel and equally important role in several signaling and cell regulatory events in breast cancer. Availability of new tools capable of sensitive detection of gene mutations and aberrant expression of genes and proteins coupled with gene-specific knockdown and silencing protocols have provided insight into the previously unexplored ubiquitin regulatory process within these tumors. Ubiquitin-specific proteases are one class of enzymes with protein deubiquitinating activity, making up the majority of protein deubiquitinating diversity within mammalian cells. Ubiquitin-specific proteases are also emerging as potential therapeutic targets in many diseases, including cancer. In this report, we summarize the involvement of this class of enzymes in breast cancer signaling and cell regulation and illustrate the potential for additional studies to define novel targets and approaches in breast cancer therapy.
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Affiliation(s)
- Anupama Pal
- Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan Comprehensive Cancer Center, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA
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305
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Hanpude P, Bhattacharya S, Dey AK, Maiti TK. Deubiquitinating enzymes in cellular signaling and disease regulation. IUBMB Life 2015; 67:544-55. [PMID: 26178252 DOI: 10.1002/iub.1402] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 12/27/2022]
Abstract
Protein post-translational modification by ubiquitin represents a complex signaling system that regulates many cellular events including proteostasis to intercellular communications. Deubiquitinating enzymes (DUBs) that specifically disassemble Ub-chains or regulate ubiquitin homeostasis reside as a central component in ubiquitin signaling. Human genome encodes almost 100 DUBs and majority of them are not well characterized. Considerable progress has been made in the understanding of enzymatic mechanism; however, their cellular substrate specificity and regulation are largely unknown. Involvement of DUBs in disease regulation has been depicted since its discovery and several attempts have been made for evaluating DUBs as a drug target. In this review, we have updated briefly a new insight of DUBs activity, their cellular role, disease regulation, and therapeutic potential.
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Affiliation(s)
- Pranita Hanpude
- Laboratory of Proteomics and Cellular Signaling, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Bhakri Village, Faridabad, India
| | - Sushmita Bhattacharya
- Laboratory of Proteomics and Cellular Signaling, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Bhakri Village, Faridabad, India
| | - Amit Kumar Dey
- Laboratory of Proteomics and Cellular Signaling, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Bhakri Village, Faridabad, India
| | - Tushar Kanti Maiti
- Laboratory of Proteomics and Cellular Signaling, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Bhakri Village, Faridabad, India
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306
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Yun SI, Kim HH, Yoon JH, Park WS, Hahn MJ, Kim HC, Chung CH, Kim KK. Ubiquitin specific protease 4 positively regulates the WNT/β-catenin signaling in colorectal cancer. Mol Oncol 2015; 9:1834-51. [PMID: 26189775 DOI: 10.1016/j.molonc.2015.06.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 12/12/2022] Open
Abstract
β-catenin is a key signal transducer in the canonical WNT pathway and is negatively regulated by ubiquitin-dependent proteolysis. Through screening of various deubiquitinating enzymes (DUBs), we identified ubiquitin specific protease 4 (USP4) as a candidate for β-catenin-specific DUB. The effects of USP4 overexpression or knockdown suggested that USP4 positively controls the stability of β-catenin and enhances β-catenin-regulated transcription. Domain mapping results revealed that the C-terminal catalytic domain is responsible for β-catenin binding and nuclear transport. Examination of colon cancer tissues from patients revealed a correlation between elevated expression levels of USP4 and β-catenin. Consistent with this correlation, USP4 knockdown in HCT116, a colon cancer cell line, reduced invasion and migration activity. These observations indicate that USP4 acts as a positive regulator of the WNT/β-catenin pathway by deubiquitination and facilitates nuclear localization of β-catenin. Therefore, we propose that USP4 is a potential target for anti-cancer therapeutics.
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Affiliation(s)
- Sun-Il Yun
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea
| | - Hyeon Ho Kim
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Seoul 135-710, South Korea; Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 135-710, South Korea
| | - Jung Hwan Yoon
- Department of Pathology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, South Korea
| | - Won Sang Park
- Department of Pathology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, South Korea
| | - Myong-Joon Hahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea
| | - Hee Cheol Kim
- Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul 135-710, South Korea
| | - Chin Ha Chung
- School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea; Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Seoul 135-710, South Korea; Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 135-710, South Korea.
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307
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Abstract
RNA stress granules (SGs) represent a cell-intrinsic antiviral defense mechanism. The assembly of SGs in response to viral infection is coordinated by the cellular protein G3BP, which is targeted by many viruses to block SG formation. We recently showed that proteins containing the short linear motif Phe-Gly-Asp-Phe (FGDF), bind G3BP in a hydrophobic groove on the surface of the nuclear transport factor-2-like domain. Binding in this manner blocks the ability of G3BP to form SGs and allows efficient replication of viruses carrying this motif.
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Affiliation(s)
- Gerald M McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet , Stockholm, Sweden
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308
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Nakagawa T, Nakayama K. Protein monoubiquitylation: targets and diverse functions. Genes Cells 2015; 20:543-62. [PMID: 26085183 PMCID: PMC4744734 DOI: 10.1111/gtc.12250] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/19/2015] [Indexed: 12/14/2022]
Abstract
Ubiquitin is a 76-amino acid protein whose conjugation to protein targets is a form of post-translational modification. Protein ubiquitylation is characterized by the covalent attachment of the COOH-terminal carboxyl group of ubiquitin to an amino group of the substrate protein. Given that the NH2 -terminal amino group is usually masked, internal lysine residues are most often targeted for ubiquitylation. Polyubiquitylation refers to the formation of a polyubiquitin chain on the substrate as a result of the ubiquitylation of conjugated ubiquitin. The structures of such polyubiquitin chains depend on the specific lysine residues of ubiquitin targeted for ubiquitylation. Most of the polyubiquitin chains other than those linked via lysine-63 and methionine-1 of ubiquitin are recognized by the proteasome and serve as a trigger for substrate degradation. In contrast, polyubiquitin chains linked via lysine-63 and methionine-1 serve as a binding platform for proteins that function in immune signal transduction or DNA repair. With the exception of a few targets such as histones, the functions of protein monoubiquitylation have remained less clear. However, recent proteomics analysis has shown that monoubiquitylation occurs more frequently than polyubiquitylation, and studies are beginning to provide insight into its biologically important functions. Here, we summarize recent findings on protein monoubiquitylation to provide an overview of the targets and molecular functions of this modification.
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Affiliation(s)
- Tadashi Nakagawa
- Division of Cell Proliferation, ART, Graduate School of Medicine, Tohoku University, Sendai, 980-8575, Miyagi, Japan
| | - Keiko Nakayama
- Division of Cell Proliferation, ART, Graduate School of Medicine, Tohoku University, Sendai, 980-8575, Miyagi, Japan
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309
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Sahtoe DD, Sixma TK. Layers of DUB regulation. Trends Biochem Sci 2015; 40:456-67. [PMID: 26073511 DOI: 10.1016/j.tibs.2015.05.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/06/2015] [Accepted: 05/11/2015] [Indexed: 11/15/2022]
Abstract
Proteolytic enzymes, such as (iso-)peptidases, are potentially hazardous for cells. To neutralize their potential danger, tight control of their activities has evolved. Deubiquitylating enzymes (DUBs) are isopeptidases involved in eukaryotic ubiquitylation. They reverse ubiquitin signals by hydrolyzing ubiquitin adducts, giving them control over all aspects of ubiquitin biology. The importance of DUB function is underscored by their frequent deregulation in human disease, making these enzymes potential drug targets. Here, we review the different layers of DUB enzyme regulation. We discuss how post-translational modification (PTM), regulatory domains within DUBs, and incorporation of DUBs into macromolecular complexes contribute to their activity. We conclude that most DUBs are likely to use a combination of these basic regulatory mechanisms.
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Affiliation(s)
- Danny D Sahtoe
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Titia K Sixma
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
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310
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Oi N, Yuan J, Malakhova M, Luo K, Li Y, Ryu J, Zhang L, Bode AM, Xu Z, Li Y, Lou Z, Dong Z. Resveratrol induces apoptosis by directly targeting Ras-GTPase-activating protein SH3 domain-binding protein 1. Oncogene 2015; 34:2660-71. [PMID: 24998844 PMCID: PMC4286533 DOI: 10.1038/onc.2014.194] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 05/06/2014] [Accepted: 05/09/2014] [Indexed: 12/12/2022]
Abstract
Resveratrol (trans-3,5,4'-truhydroxystilbene) possesses a strong anticancer activity exhibited as the induction of apoptosis through p53 activation. However, the molecular mechanism and direct target(s) of resveratrol-induced p53 activation remain elusive. Here, the Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) was identified as a potential target of resveratrol, and in vitro binding assay results using resveratrol-conjugated Sepharose 4B beads confirmed their direct binding. Depletion of G3BP1 significantly diminishes resveratrol-induced p53 expression and apoptosis. We also found that G3BP1 negatively regulates p53 expression by interacting with ubiquitin-specific protease 10 (USP10), a deubiquitinating enzyme of p53. Disruption of the interaction of p53 with USP10 by G3BP1 interference leads to the suppression of p53 deubiquitination. Resveratrol, on the other hand, directly binds to G3BP1 and prevents the G3BP1/USP10 interaction, resulting in enhanced USP10-mediated deubiquitination of p53, and consequently increased p53 expression. These findings disclose a novel mechanism of resveratrol-induced p53 activation and resveratrol-induced apoptosis by direct targeting of G3BP1.
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Affiliation(s)
- Naomi Oi
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Jian Yuan
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
| | - Margarita Malakhova
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Kuntian Luo
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Yunhui Li
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Joohyun Ryu
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Lei Zhang
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Ann M. Bode
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Zengguang Xu
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
| | - Yan Li
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Zhenkun Lou
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
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311
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Panas MD, Kedersha N, McInerney GM. Methods for the characterization of stress granules in virus infected cells. Methods 2015; 90:57-64. [PMID: 25896634 PMCID: PMC7128402 DOI: 10.1016/j.ymeth.2015.04.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 12/25/2022] Open
Abstract
Stress granules are induced as a cellular defence against virus infection. We discuss methods for the detection of viral and cellular proteins and RNA in SGs. In addition, we describe a surrogate in vitro assay for SG formation.
Stress granules are induced in many different viral infections, and in turn are inhibited by the expression of viral proteins or RNAs. It is therefore evident that these bodies are not compatible with efficient viral replication, but the mechanism by which they act to restrict viral gene expression or genome replication is not yet understood. This article discusses a number of methods that can be employed to gain a more complete understanding of the relationship between cellular SGs and viral RNA and protein synthesis in cells infected with diverse viruses.
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Affiliation(s)
- Marc D Panas
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Nancy Kedersha
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA
| | - Gerald M McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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312
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Abstract
The post-translational modification of proteins with ubiquitin represents a complex signalling system that co-ordinates essential cellular functions, including proteolysis, DNA repair, receptor signalling and cell communication. DUBs (deubiquitinases), the enzymes that disassemble ubiquitin chains and remove ubiquitin from proteins, are central to this system. Reflecting the complexity and versatility of ubiquitin signalling, DUB activity is controlled in multiple ways. Although several lines of evidence indicate that aberrant DUB function may promote human disease, the underlying molecular mechanisms are often unclear. Notwithstanding, considerable interest in DUBs as potential drug targets has emerged over the past years. The future success of DUB-based therapy development will require connecting the basic science of DUB function and enzymology with drug discovery. In the present review, we discuss new insights into DUB activity regulation and their links to disease, focusing on the role of DUBs as regulators of cell identity and differentiation, and discuss their potential as emerging drug targets.
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313
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Wang W, Huang X, Xin HB, Fu M, Xue A, Wu ZH. TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase. J Biol Chem 2015; 290:13372-85. [PMID: 25861989 DOI: 10.1074/jbc.m115.643767] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Indexed: 01/26/2023] Open
Abstract
DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination.
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Affiliation(s)
- Wei Wang
- From the Department of Pathology and Laboratory Medicine and Center for Cancer Research, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Xuan Huang
- the Institute of Translational Medicine, Nanchang University, Nanchang 330031, China
| | - Hong-Bo Xin
- the Institute of Translational Medicine, Nanchang University, Nanchang 330031, China
| | - Mingui Fu
- the Department of Basic Medical Science, University of Missouri Kansas City, Kansas City, Missouri 64108, and
| | - Aimin Xue
- the Department of Forensic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhao-Hui Wu
- From the Department of Pathology and Laboratory Medicine and Center for Cancer Research, University of Tennessee Health Science Center, Memphis, Tennessee 38163,
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314
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Jeong CH. Inhibition of Ubiquitin-specific Peptidase 8 Suppresses Growth of Gefitinib-resistant Non-small Cell Lung Cancer Cells by Inducing Apoptosis. J Cancer Prev 2015; 20:57-63. [PMID: 25853104 PMCID: PMC4384715 DOI: 10.15430/jcp.2015.20.1.57] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 02/26/2015] [Accepted: 02/26/2015] [Indexed: 01/17/2023] Open
Abstract
Background: Therapeutic approach by treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) like gefitinib or erlotinib to non-small cell lung cancer (NSCLC) patients has been limited due to emergence of acquired drug resistance. Our study was aimed to investigate whether the inhibition of ubiquitin-specific peptidase 8 (USP8) could be an alternative strategy capable of overcoming acquired resistance to EGFR-TKIs for treatment of NSCLCs. Methods: The anticancer effect of USP8 inhibitor was determined by testing anchorage-dependent or independent growth of gefitinib-sensitive or resistant NSCLCs. The immunoprecipitation and western blotting were conducted to check molecular interaction and signaling pathway followed by USP8 inhibition. Results: Inhibition of USP8 induced overall degradation of oncogenic receptor tyrosine kinases including EGFR and Met, leading to a suppression of anchorage-dependent or independent cell growth of gefitinib-sensitive or resistant NSCLCs. Also, treatment with the USP8 inhibitor markedly induced apoptosis in HCC827GR cells. Notably, treatment with the USP8 inhibitor was more effective in suppressing cell growth and inducing apoptosis in gefitinib-resistant HCC827GR cells than that of gefitinib-sensitive HCC827 cells. Conclusions: Inhibition of USP8 could be an effective strategy for overcoming gefitinib resistance in NSCLCs.
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Affiliation(s)
- Chul-Ho Jeong
- College of Pharmacy, Keimyung University, Daegu, Korea
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315
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Brinkmann K, Schell M, Hoppe T, Kashkar H. Regulation of the DNA damage response by ubiquitin conjugation. Front Genet 2015; 6:98. [PMID: 25806049 PMCID: PMC4354423 DOI: 10.3389/fgene.2015.00098] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/23/2015] [Indexed: 12/12/2022] Open
Abstract
In response to DNA damage, cells activate a highly conserved and complex kinase-based signaling network, commonly referred to as the DNA damage response (DDR), to safeguard genomic integrity. The DDR consists of a set of tightly regulated events, including detection of DNA damage, accumulation of DNA repair factors at the site of damage, and finally physical repair of the lesion. Upon overwhelming damage the DDR provokes detrimental cellular actions by involving the apoptotic machinery and inducing a coordinated demise of the damaged cells (DNA damage-induced apoptosis, DDIA). These diverse actions involve transcriptional activation of several genes that govern the DDR. Moreover, recent observations highlighted the role of ubiquitylation in orchestrating the DDR, providing a dynamic cellular regulatory circuit helping to guarantee genomic stability and cellular homeostasis (Popovic et al., 2014). One of the hallmarks of human cancer is genomic instability (Hanahan and Weinberg, 2011). Not surprisingly, deregulation of the DDR can lead to human diseases, including cancer, and can induce resistance to genotoxic anti-cancer therapy (Lord and Ashworth, 2012). Here, we summarize the role of ubiquitin-signaling in the DDR with special emphasis on its role in cancer and highlight the therapeutic value of the ubiquitin-conjugation machinery as a target in anti-cancer treatment strategy.
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Affiliation(s)
- Kerstin Brinkmann
- Centre for Molecular Medicine Cologne and Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of CologneCologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University Hospital of CologneCologne, Germany
| | - Michael Schell
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University Hospital of CologneCologne, Germany
- Institute for Genetics, University of CologneCologne, Germany
| | - Thorsten Hoppe
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University Hospital of CologneCologne, Germany
- Institute for Genetics, University of CologneCologne, Germany
| | - Hamid Kashkar
- Centre for Molecular Medicine Cologne and Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of CologneCologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University Hospital of CologneCologne, Germany
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316
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TRIM25 has a dual function in the p53/Mdm2 circuit. Oncogene 2015; 34:5729-38. [PMID: 25728675 DOI: 10.1038/onc.2015.21] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 12/17/2014] [Accepted: 12/19/2014] [Indexed: 12/20/2022]
Abstract
P53 is an important tumor suppressor that, upon activation, induces growth arrest and cell death. Control of p53 is thus of prime importance for proliferating cells, but also for cancer therapy, where p53 activity contributes to the eradication of tumors. Mdm2 functionally inhibits p53 and targets the tumor suppressor protein for degradation. In a genetic screen, we identified TRIM25 as a novel regulator of p53 and Mdm2. TRIM25 increased p53 and Mdm2 abundance by inhibiting their ubiquitination and degradation in 26 S proteasomes. TRIM25 co-precipitated with p53 and Mdm2 and interfered with the association of p300 and Mdm2, a critical step for p53 polyubiquitination. Despite the increase in p53 levels, p53 activity was inhibited in the presence of TRIM25. Downregulation of TRIM25 resulted in an increased acetylation of p53 and p53-dependent cell death in HCT116 cells. Upon genotoxic insults, TRIM25 dampened the p53-dependent DNA damage response. The downregulation of TRIM25 furthermore resulted in massive apoptosis during early embryogenesis of medaka, which was rescued by the concomitant downregulation of p53, demonstrating the functional relevance of the regulation of p53 by TRIM25 in an organismal context.
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317
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Deubiquitinase inhibition as a cancer therapeutic strategy. Pharmacol Ther 2015; 147:32-54. [DOI: 10.1016/j.pharmthera.2014.11.002] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 12/27/2022]
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318
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Panas MD, Schulte T, Thaa B, Sandalova T, Kedersha N, Achour A, McInerney GM. Viral and cellular proteins containing FGDF motifs bind G3BP to block stress granule formation. PLoS Pathog 2015; 11:e1004659. [PMID: 25658430 PMCID: PMC4450067 DOI: 10.1371/journal.ppat.1004659] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 01/06/2015] [Indexed: 02/08/2023] Open
Abstract
The Ras-GAP SH3 domain-binding proteins (G3BP) are essential regulators of the formation of stress granules (SG), cytosolic aggregates of proteins and RNA that are induced upon cellular stress, such as virus infection. Many viruses, including Semliki Forest virus (SFV), block SG induction by targeting G3BP. In this work, we demonstrate that the G3BP-binding motif of SFV nsP3 consists of two FGDF motifs, in which both phenylalanine and the glycine residue are essential for binding. In addition, we show that binding of the cellular G3BP-binding partner USP10 is also mediated by an FGDF motif. Overexpression of wt USP10, but not a mutant lacking the FGDF-motif, blocks SG assembly. Further, we identified FGDF-mediated G3BP binding site in herpes simplex virus (HSV) protein ICP8, and show that ICP8 binding to G3BP also inhibits SG formation, which is a novel function of HSV ICP8. We present a model of the three-dimensional structure of G3BP bound to an FGDF-containing peptide, likely representing a binding mode shared by many proteins to target G3BP.
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Affiliation(s)
- Marc D. Panas
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Tim Schulte
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Bastian Thaa
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Tatiana Sandalova
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Nancy Kedersha
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Adnane Achour
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Gerald M. McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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319
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Zhang L, Gong F. Involvement of USP24 in the DNA damage response. Mol Cell Oncol 2015; 3:e1011888. [PMID: 27308530 DOI: 10.1080/23723556.2015.1011888] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 10/23/2022]
Abstract
Deubiquitination has emerged as an important mechanism of regulating DNA repair pathways. We recently reported that USP24 is a novel p53 deubiquitinase that stabilizes p53 upon DNA damage. USP24 is upregulated by DNA damaging agents and plays an important role in maintaining genome stability.
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Affiliation(s)
- Ling Zhang
- Department of Biochemistry and Molecular Biology; University of Miami Miller School of Medicine ; Miami, FL USA
| | - Feng Gong
- Department of Biochemistry and Molecular Biology; University of Miami Miller School of Medicine ; Miami, FL USA
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320
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Zhang L, Nemzow L, Chen H, Lubin A, Rong X, Sun Z, Harris TK, Gong F. The deubiquitinating enzyme USP24 is a regulator of the UV damage response. Cell Rep 2015; 10:140-7. [PMID: 25578727 DOI: 10.1016/j.celrep.2014.12.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 11/17/2014] [Accepted: 12/11/2014] [Indexed: 02/06/2023] Open
Abstract
Regulation of p53 by ubiquitination and deubiquitination is important for its function. In this study, we demonstrate that USP24 deubiquitinates p53 in human cells. Functional USP24 is required for p53 stabilization, and p53 destabilization in USP24-depleted cells can be corrected by the forced expression of USP24. We show that USP24 depletion renders cells resistant to apoptosis after UV irradiation, consistent with the requirement of USP24 for p53 stabilization and PUMA activation in vivo. Additionally, purified USP24 protein is able to cleave ubiquitinated p53 in vitro. Importantly, cells with USP24 depletion exhibited significantly elevated mutation rates at the endogenous HPRT locus, implying an important role for USP24 in maintaining genome stability. Our data reveal that the USP24 deubiquitinase regulates the DNA damage response by directly targeting the p53 tumor suppressor.
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Affiliation(s)
- Ling Zhang
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Leah Nemzow
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Hua Chen
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Abigail Lubin
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xi Rong
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Zhongyi Sun
- Department of Urology and Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Thomas K Harris
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Feng Gong
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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321
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Takeda H, Wei Z, Koso H, Rust AG, Yew CCK, Mann MB, Ward JM, Adams DJ, Copeland NG, Jenkins NA. Transposon mutagenesis identifies genes and evolutionary forces driving gastrointestinal tract tumor progression. Nat Genet 2015; 47:142-50. [PMID: 25559195 DOI: 10.1038/ng.3175] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 12/04/2014] [Indexed: 12/14/2022]
Abstract
To provide a more comprehensive understanding of the genes and evolutionary forces driving colorectal cancer (CRC) progression, we performed Sleeping Beauty (SB) transposon mutagenesis screens in mice carrying sensitizing mutations in genes that act at different stages of tumor progression. This approach allowed us to identify a set of genes that appear to be highly relevant for CRC and to provide a better understanding of the evolutionary forces and systems properties of CRC. We also identified six genes driving malignant tumor progression and a new human CRC tumor-suppressor gene, ZNF292, that might also function in other types of cancer. Our comprehensive CRC data set provides a resource with which to develop new therapies for treating CRC.
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Affiliation(s)
- Haruna Takeda
- 1] Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore. [2] Department of Oncologic Pathology, School of Medicine, Kanazawa Medical University, Ishikawa, Japan
| | - Zhubo Wei
- Cancer Research Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Hideto Koso
- 1] Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore. [2] Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Alistair G Rust
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Christopher Chin Kuan Yew
- Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Michael B Mann
- 1] Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore. [2] Cancer Research Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Jerrold M Ward
- Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - David J Adams
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Neal G Copeland
- 1] Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore. [2] Cancer Research Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Nancy A Jenkins
- 1] Division of Genomics and Genetics, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore. [2] Cancer Research Program, Houston Methodist Research Institute, Houston, Texas, USA
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322
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Mechanisms of p53 degradation. Clin Chim Acta 2015; 438:139-47. [DOI: 10.1016/j.cca.2014.08.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 11/19/2022]
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323
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Kumari R, Kohli S, Das S. p53 regulation upon genotoxic stress: intricacies and complexities. Mol Cell Oncol 2014; 1:e969653. [PMID: 27308356 DOI: 10.4161/23723548.2014.969653] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 12/11/2022]
Abstract
p53, the revered savior of genomic integrity, receives signals from diverse stress sensors and strategizes to maintain cellular homeostasis. However, the predominance of p53 overshadows the fact that this herculean task is no one-man show; rather, there is a huge army of regulators that reign over p53 at various levels to avoid an unnecessary surge in its levels and sculpt it dynamically to favor one cellular outcome over another. This governance starts right at the time of p53 translation, which is gated by proteins that bind to p53 mRNA and keep a stringent check on p53 protein levels. The same effect is also achieved by ubiquitylases and deubiquitylases that fine-tune p53 turnover and miRNAs that modulate p53 levels, adding precision to this entire scheme. In addition, extensive covalent modifications and differential protein interactions allow p53 to trigger a tailor-made response for a given circumstance. To magnify the marvel, these various tiers of regulation operate simultaneously and in various combinations. In this review, we have tried to provide a glimpse into this bewildering labyrinth. We believe that further studies will result in a better understanding of p53 regulation and that new insights will help unravel many aspects of cancer biology.
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Affiliation(s)
- Rajni Kumari
- Molecular Oncology Laboratory; National Institute of Immunology ; New Delhi, India
| | - Saishruti Kohli
- Molecular Oncology Laboratory; National Institute of Immunology ; New Delhi, India
| | - Sanjeev Das
- Molecular Oncology Laboratory; National Institute of Immunology ; New Delhi, India
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324
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Reidick C, El Magraoui F, Meyer HE, Stenmark H, Platta HW. Regulation of the Tumor-Suppressor Function of the Class III Phosphatidylinositol 3-Kinase Complex by Ubiquitin and SUMO. Cancers (Basel) 2014; 7:1-29. [PMID: 25545884 PMCID: PMC4381249 DOI: 10.3390/cancers7010001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/08/2014] [Indexed: 12/19/2022] Open
Abstract
The occurrence of cancer is often associated with a dysfunction in one of the three central membrane-involution processes—autophagy, endocytosis or cytokinesis. Interestingly, all three pathways are controlled by the same central signaling module: the class III phosphatidylinositol 3-kinase (PI3K-III) complex and its catalytic product, the phosphorylated lipid phosphatidylinositol 3-phosphate (PtdIns3P). The activity of the catalytic subunit of the PI3K-III complex, the lipid-kinase VPS34, requires the presence of the membrane-targeting factor VPS15 as well as the adaptor protein Beclin 1. Furthermore, a growing list of regulatory proteins associates with VPS34 via Beclin 1. These accessory factors define distinct subunit compositions and thereby guide the PI3K-III complex to its different cellular and physiological roles. Here we discuss the regulation of the PI3K-III complex components by ubiquitination and SUMOylation. Especially Beclin 1 has emerged as a highly regulated protein, which can be modified with Lys11-, Lys48- or Lys63-linked polyubiquitin chains catalyzed by distinct E3 ligases from the RING-, HECT-, RBR- or Cullin-type. We also point out other cross-links of these ligases with autophagy in order to discuss how these data might be merged into a general concept.
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Affiliation(s)
- Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum 44801, Germany.
| | - Fouzi El Magraoui
- Biomedical Research, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften-ISAS, Dortmund 44139, Germany.
| | - Helmut E Meyer
- Biomedical Research, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften-ISAS, Dortmund 44139, Germany.
| | - Harald Stenmark
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo 0310, Norway.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum 44801, Germany.
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325
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Hock AK, Vigneron AM, Vousden KH. Ubiquitin-specific peptidase 42 (USP42) functions to deubiquitylate histones and regulate transcriptional activity. J Biol Chem 2014; 289:34862-70. [PMID: 25336640 PMCID: PMC4263885 DOI: 10.1074/jbc.m114.589267] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/21/2014] [Indexed: 12/22/2022] Open
Abstract
Ubiquitin-specific peptidase 42 (USP42) is a deubiquitylating enzyme that can target p53 and contribute to the stabilization of p53 in response to stress. We now show that USP42 can also regulate transcription independently of p53. USP42 co-localized with RNA polymerase II (RNA Pol II) in nuclear foci, bound to histone H2B, and deubiquitylated H2B. Depletion of USP42 increased H2B ubiquitylation at a model promoter and decreased both basal and induced transcription from a number of promoters. These results are consistent with a role for USP42 in regulating transcription by deubiquitylating histones.
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Affiliation(s)
- Andreas K Hock
- From the Cancer Research UK Beatson Institute, Glasgow G61 1BD, Scotland, United Kingdom
| | - Arnaud M Vigneron
- From the Cancer Research UK Beatson Institute, Glasgow G61 1BD, Scotland, United Kingdom
| | - Karen H Vousden
- From the Cancer Research UK Beatson Institute, Glasgow G61 1BD, Scotland, United Kingdom
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326
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Automated analysis of immunohistochemistry images identifies candidate location biomarkers for cancers. Proc Natl Acad Sci U S A 2014; 111:18249-54. [PMID: 25489103 DOI: 10.1073/pnas.1415120112] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Molecular biomarkers are changes measured in biological samples that reflect disease states. Such markers can help clinicians identify types of cancer or stages of progression, and they can guide in tailoring specific therapies. Many efforts to identify biomarkers consider genes that mutate between normal and cancerous tissues or changes in protein or RNA expression levels. Here we define location biomarkers, proteins that undergo changes in subcellular location that are indicative of disease. To discover such biomarkers, we have developed an automated pipeline to compare the subcellular location of proteins between two sets of immunohistochemistry images. We used the pipeline to compare images of healthy and tumor tissue from the Human Protein Atlas, ranking hundreds of proteins in breast, liver, prostate, and bladder based on how much their location was estimated to have changed. The performance of the system was evaluated by determining whether proteins previously known to change location in tumors were ranked highly. We present a number of candidate location biomarkers for each tissue, and identify biochemical pathways that are enriched in proteins that change location. The analysis technology is anticipated to be useful not only for discovering new location biomarkers but also for enabling automated analysis of biomarker distributions as an aid to determining diagnosis.
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327
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Park SY, Choi HK, Choi Y, Kwak S, Choi KC, Yoon HG. Deubiquitinase OTUD5 mediates the sequential activation of PDCD5 and p53 in response to genotoxic stress. Cancer Lett 2014; 357:419-427. [PMID: 25499082 DOI: 10.1016/j.canlet.2014.12.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/02/2014] [Accepted: 12/02/2014] [Indexed: 11/27/2022]
Abstract
Programmed cell death 5 (PDCD5) positively regulates p53-mediated apoptosis and rapidly accumulates upon DNA damage. However, the underlying mechanism of PDCD5 upregulation during the DNA damage response remains unknown. Here, we found that OTU deubiquitinase 5 (OTUD5) was bound to PDCD5 in response to etoposide treatment and increased the stability of PDCD5 by mediating deubiquitination of PDCD5 at Lys-97/98. Overexpression of OTUD5 efficiently enhanced the activation of both PDCD5 and p53. Conversely, PDCD5 knockdown greatly attenuated the effect of OTUD5 on p53 activation. In addition, when OTUD5 was depleted, PDCD5 failed to facilitate p53 activation, demonstrating an essential role for the PDCD5-OTUD5 network in p53 activation. Importantly, we found that OTUD5-dependent PDCD5 stabilization was required for sequential activation of p53 in response to genotoxic stress. The sequential activation of PDCD5 and p53 was abrogated by knockdown of OTUD5. Finally, impairment of the genotoxic stress response upon PDCD5 ablation was substantially rescued by reintroducing PDCD5(WT) but not PDCD5(E94D) (defective for OTUD5 interaction) or PDCD5(E16D) (defective for p53 interaction). Together, our findings have uncovered an apoptotic signaling cascade linking PDCD5, OTUD5, and p53 during genotoxic stress responses.
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Affiliation(s)
- Soo-Yeon Park
- Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, Brain Korea 21 Project for Medical Sciences, Severance Medical Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hyo-Kyoung Choi
- Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, Brain Korea 21 Project for Medical Sciences, Severance Medical Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Youngsok Choi
- Fertility Center of CHA General Hospital, CHA Research Institute, CHA University, Seoul, Korea
| | - Sungmin Kwak
- Department of Biomedical Sciences and Department of Pharmacology, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyung-Chul Choi
- Department of Biomedical Sciences and Department of Pharmacology, University of Ulsan College of Medicine, Seoul, Korea.
| | - Ho-Geun Yoon
- Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic Disease Research, Brain Korea 21 Project for Medical Sciences, Severance Medical Research Institute, Yonsei University College of Medicine, Seoul, Korea
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328
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Zhu M, Zhao H, Liao J, Xu X. HERC2/USP20 coordinates CHK1 activation by modulating CLASPIN stability. Nucleic Acids Res 2014; 42:13074-81. [PMID: 25326330 PMCID: PMC4245974 DOI: 10.1093/nar/gku978] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 09/21/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022] Open
Abstract
CLASPIN is an essential mediator in the DNA replication checkpoint, responsible for ATR (ataxia telangiectasia and Rad3-related protein)-dependent activation of CHK1 (checkpoint kinase 1). Here we found a dynamic signaling pathway that regulates CLASPIN turn over. Under unperturbed conditions, the E3 ubiquitin ligase HERC2 regulates the stability of the deubiquitinating enzyme USP20 by promoting ubiquitination-mediated proteasomal degradation. Under replication stress, ATR-mediated phosphorylation of USP20 results in the disassociation of HERC2 from USP20. USP20 in turn deubiquitinates K48-linked-polyubiquitinated CLASPIN, stabilizing CLASPIN and ultimately promoting CHK1 phosphorylation and CHK1-directed checkpoint activation. Inhibition of USP20 expression promotes chromosome instability and xenograft tumor growth. Taken together, our findings demonstrated a novel function of HERC2/USP20 in coordinating CHK1 activation by modulating CLASPIN stability, which ultimately promotes genome stability and suppresses tumor growth.
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Affiliation(s)
- Min Zhu
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Hongchang Zhao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Ji Liao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Xingzhi Xu
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
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329
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Abstract
The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor-suppressing lipid phosphatase that is frequently absent in breast tumors. Thus, the stability of PTEN is essential for tumor prevention and therapy. The ubiquitinproteasome pathway has an important role in regulating the functions of PTEN. Specifically, carboxyl terminus Hsp70-interacting protein (CHIP), the E3 ubiquitin ligase of PTEN, can regulate PTEN levels. In this study, we report that BCL-2- associated athanogene 5 (BAG5), a known inhibitor of CHIP activity, reduces the degradation of PTEN and maintains its levels via an ubiquitylation-dependent pathway. BAG5 is identified as an antagonist of cell tumorigenicity. [BMB Reports 2013; 46(10): 490-494]
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Affiliation(s)
- Zhang Ying
- Department of Breast Surgery, QiLu Hospital of Shandong University, China
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330
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Pan J, Deng Q, Jiang C, Wang X, Niu T, Li H, Chen T, Jin J, Pan W, Cai X, Yang X, Lu M, Xiao J, Wang P. USP37 directly deubiquitinates and stabilizes c-Myc in lung cancer. Oncogene 2014; 34:3957-67. [DOI: 10.1038/onc.2014.327] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 08/03/2014] [Accepted: 08/19/2014] [Indexed: 01/07/2023]
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331
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ABRO1 suppresses tumourigenesis and regulates the DNA damage response by stabilizing p53. Nat Commun 2014; 5:5059. [PMID: 25283148 PMCID: PMC4205886 DOI: 10.1038/ncomms6059] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 08/21/2014] [Indexed: 01/02/2023] Open
Abstract
Abraxas brother 1 (ABRO1) has been reported to be a component of the BRISC complex, a multiprotein complex that specifically cleaves 'Lys-63'-linked ubiquitin. However, current knowledge of the functions of ABRO1 is limited. Here we report that ABRO1 is frequently downregulated in human liver, kidney, breast and thyroid gland tumour tissues. Depletion of ABRO1 in cancer cells reduces p53 levels and enhances clone formation and cellular transformation. Conversely, overexpression of ABRO1 suppresses cell proliferation and tumour formation in a p53-dependent manner. We further show that ABRO1 stabilizes p53 by facilitating the interaction of p53 with USP7. DNA-damage induced accumulation of endogenous ABRO1 as well as translocation of ABRO1 to the nucleus, and the induction of p53 by DNA damage is almost completely attenuated by ABRO1 depletion. Our study shows that ABRO1 is a novel p53 regulator that plays an important role in tumour suppression and the DNA damage response.
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332
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Abstract
The ubiquitin proteasome pathway is critical in restraining the activities of the p53 tumor suppressor. This review by Pant and Lozano focuses on ubiquitination as a mechanism for regulating p53 stability and function and reviews current findings from in vivo models that evaluate the importance of the ubiquitin proteasome system in regulating p53. The ubiquitin proteasome pathway is critical in restraining the activities of the p53 tumor suppressor. Numerous E3 and E4 ligases regulate p53 levels. Additionally, deubquitinating enzymes that modify p53 directly or indirectly also impact p53 function. When alterations of these proteins result in increased p53 activity, cells arrest in the cell cycle, senesce, or apoptose. On the other hand, alterations that result in decreased p53 levels yield tumor-prone phenotypes. This review focuses on the physiological relevance of these important regulators of p53 and their therapeutic implications.
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Affiliation(s)
- Vinod Pant
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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333
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Activation of diverse signalling pathways by oncogenic PIK3CA mutations. Nat Commun 2014; 5:4961. [PMID: 25247763 PMCID: PMC4210192 DOI: 10.1038/ncomms5961] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 08/12/2014] [Indexed: 12/13/2022] Open
Abstract
The PIK3CA gene is frequently mutated in human cancers. Here we carry out a SILAC-based quantitative phosphoproteomic analysis using isogenic knockin cell lines containing ‘driver’ oncogenic mutations of PIK3CA to dissect the signaling mechanisms responsible for oncogenic phenotypes induced by mutant PIK3CA. From 8,075 unique phosphopeptides identified, we observe that aberrant activation of PI3K pathway leads to increased phosphorylation of a surprisingly wide variety of kinases and downstream signaling networks. Here, by integrating phosphoproteomic data with human protein microarray-based AKT1 kinase assays, we discover and validate six novel AKT1 substrates, including cortactin. Through mutagenesis studies, we demonstrate that phosphorylation of cortactin by AKT1 is important for mutant PI3K enhanced cell migration and invasion. Our study describes a quantitative and global approach for identifying mutation-specific signaling events and for discovering novel signaling molecules as readouts of pathway activation or potential therapeutic targets.
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334
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The cultural divide: exponential growth in classical 2D and metabolic equilibrium in 3D environments. PLoS One 2014; 9:e106973. [PMID: 25222612 PMCID: PMC4164521 DOI: 10.1371/journal.pone.0106973] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/04/2014] [Indexed: 01/26/2023] Open
Abstract
INTRODUCTION Cellular metabolism can be considered to have two extremes: one is characterized by exponential growth (in 2D cultures) and the other by a dynamic equilibrium (in 3D cultures). We have analyzed the proteome and cellular architecture at these two extremes and found that they are dramatically different. RESULTS Structurally, actin organization is changed, microtubules are increased and keratins 8 and 18 decreased. Metabolically, glycolysis, fatty acid metabolism and the pentose phosphate shunt are increased while TCA cycle and oxidative phosphorylation is unchanged. Enzymes involved in cholesterol and urea synthesis are increased consistent with the attainment of cholesterol and urea production rates seen in vivo. DNA repair enzymes are increased even though cells are predominantly in Go. Transport around the cell--along the microtubules, through the nuclear pore and in various types of vesicles has been prioritized. There are numerous coherent changes in transcription, splicing, translation, protein folding and degradation. The amount of individual proteins within complexes is shown to be highly coordinated. Typically subunits which initiate a particular function are present in increased amounts compared to other subunits of the same complex. SUMMARY We have previously demonstrated that cells at dynamic equilibrium can match the physiological performance of cells in tissues in vivo. Here we describe the multitude of protein changes necessary to achieve this performance.
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335
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Pal A, Young MA, Donato NJ. Emerging potential of therapeutic targeting of ubiquitin-specific proteases in the treatment of cancer. Cancer Res 2014; 74:4955-66. [PMID: 25172841 DOI: 10.1158/0008-5472.can-14-1211] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The ubiquitin-proteasome system (UPS) has emerged as a therapeutic focus and target for the treatment of cancer. The most clinically successful UPS-active agents (bortezomib and lenalidomide) are limited in application to hematologic malignancies, with only marginal efficacy in solid tumors. Inhibition of specific ubiquitin E3 ligases has also emerged as a valid therapeutic strategy, and many targets are currently being investigated. Another emerging and promising approach in regulation of the UPS involves targeting deubiquitinases (DUB). The DUBs comprise a relatively small group of proteins, most with cysteine protease activity that target several key proteins involved in regulation of tumorigenesis, apoptosis, senescence, and autophagy. Through their multiple contacts with ubiquitinated protein substrates involved in these pathways, DUBs provide an untapped means of modulating many important regulatory proteins that support oncogenic transformation and progression. Ubiquitin-specific proteases (USP) are one class of DUBs that have drawn special attention as cancer targets, as many are differentially expressed or activated in tumors or their microenvironment, making them ideal candidates for drug development. This review attempts to summarize the USPs implicated in different cancers, the current status of USP inhibitor-mediated pharmacologic intervention, and future prospects for USP inhibitors to treat diverse cancers.
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Affiliation(s)
- Anupama Pal
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Matthew A Young
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Nicholas J Donato
- Division of Hematology/Oncology, Department of Internal Medicine, University of Michigan School of Medicine and Comprehensive Cancer Center, Ann Arbor, Michigan.
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336
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Liu H, Xu XF, Zhao Y, Tang MC, Zhou YQ, Lu J, Gao FH. MicroRNA-191 promotes pancreatic cancer progression by targeting USP10. Tumour Biol 2014; 35:12157-63. [PMID: 25168367 DOI: 10.1007/s13277-014-2521-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/18/2014] [Indexed: 12/14/2022] Open
Abstract
Recent studies have shown that microRNAs, a class of small and noncoding RNA molecules, play crucial roles in the initiation and progression of pancreatic cancer. In the present study, the expression and roles of miR-191 were investigated. Through both gain-of function and loss-of function experiments, a pro-oncogenic function of miR-191 was demonstrated. At the molecular level, bioinformatic prediction, luciferase, and protein expression analysis suggested that miR-191 could inhibit protein levels of UPS10, which suppressed the proliferation and growth of cancer cells through stabilizing P53 protein. Collectively, these data suggest that miR-191 could promote pancreatic cancer progression through targeting USP10, implicating a novel mechanism for the tumorigenesis.
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Affiliation(s)
- Hua Liu
- Department of Gastroenterology, The Tenth Hospital Affiliated to Tongji University, No. 301, Yanchang Road, 200072, Shanghai, China
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337
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Ayroldi E, Petrillo MG, Bastianelli A, Marchetti MC, Ronchetti S, Nocentini G, Ricciotti L, Cannarile L, Riccardi C. L-GILZ binds p53 and MDM2 and suppresses tumor growth through p53 activation in human cancer cells. Cell Death Differ 2014; 22:118-30. [PMID: 25168242 DOI: 10.1038/cdd.2014.129] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 07/16/2014] [Accepted: 07/21/2014] [Indexed: 12/31/2022] Open
Abstract
The transcription factor p53 regulates the expression of genes crucial for biological processes such as cell proliferation, metabolism, cell repair, senescence and apoptosis. Activation of p53 also suppresses neoplastic transformations, thereby inhibiting the growth of mutated and/or damaged cells. p53-binding proteins, such as mouse double minute 2 homolog (MDM2), inhibit p53 activation and thus regulate p53-mediated stress responses. Here, we found that long glucocorticoid-induced leucine zipper (L-GILZ), a recently identified isoform of GILZ, activates p53 and that the overexpression of L-GILZ in p53(+/+) HCT116 human colorectal carcinoma cells suppresses the growth of xenografts in mice. In the presence of both p53 and MDM2, L-GILZ binds preferentially to MDM2 and interferes with p53/MDM2 complex formation, making p53 available for downstream gene activation. Consistent with this finding, L-GILZ induced p21 and p53 upregulated modulator of apoptosis (PUMA) expression only in p53(+/+) cells, while L-GILZ silencing reversed the anti-proliferative activity of dexamethasone as well as expression of p53, p21 and PUMA. Furthermore, L-GILZ stabilizes p53 proteins by decreasing p53 ubiquitination and increasing MDM2 ubiquitination. These findings reveal L-GILZ as a regulator of p53 and a candidate for new therapeutic anti-cancer strategies for tumors associated with p53 deregulation.
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Affiliation(s)
- E Ayroldi
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - M G Petrillo
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - A Bastianelli
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - M C Marchetti
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - S Ronchetti
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - G Nocentini
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - L Ricciotti
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - L Cannarile
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
| | - C Riccardi
- Department Medicine, Section of Pharmacology, University of Perugia Medical School, Perugia, Italy
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338
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Down-regulation of HDAC5 inhibits growth of human hepatocellular carcinoma by induction of apoptosis and cell cycle arrest. Tumour Biol 2014; 35:11523-32. [PMID: 25129440 DOI: 10.1007/s13277-014-2358-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 10/24/2022] Open
Abstract
Histone deacetylases (HDACs) play a critical role in the proliferation, differentiation, and apoptosis of cancer cells. An obstacle for the application of HDAC inhibitors as effective anti-cancer therapeutics is that our current knowledge on the contributions of different HDACs in various cancer types remains scarce. The present study reported that the mRNA and protein levels of HDAC5 were up-regulated in human hepatocellular carcinoma (HCC) tissues and cells as shown by quantitative real-time PCR and Western blot. MTT assay and BrdU incorporation assay showed that the down-regulation of HDAC5 inhibited cell proliferation in HepG2, Hep3B, and Huh7 cell lines. Data from in vivo xenograft tumorigenesis model also demonstrated the anti-proliferative effect of HDAC5 depletion on tumor cell growth. Furthermore, the suppression of HDAC5 promoted cell apoptosis and induced G1-phase cell cycle arrest in HCC cells. On the molecular level, we observed altered expression of apoptosis-related proteins such as p53, bax, bcl-2, cyto C, and caspase 3 in HDAC5-shRNA-transfected cells. Knockdown of HDAC5 led to a significant up-regulation of p21 and down-regulation of cyclin D1 and CDK2/4/6. We also found that the down-regulation of HDAC5 substantially increased p53 stability and promoted its nuclear localization and transcriptional activity. Our study suggested that knockdown of HDAC5 could inhibit cancer cell proliferation by the induction of cell cycle arrest and apoptosis; thus, suppression of HDAC5 may be a viable option for treating HCC patients.
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339
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ATM-mediated stabilization of ZEB1 promotes DNA damage response and radioresistance through CHK1. Nat Cell Biol 2014; 16:864-75. [PMID: 25086746 PMCID: PMC4150825 DOI: 10.1038/ncb3013] [Citation(s) in RCA: 343] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 06/23/2014] [Indexed: 02/06/2023]
Abstract
Epithelial-mesenchymal transition (EMT) is associated with
characteristics of breast cancer stem cells, including chemoresistance and
radioresistance. However, it is unclear whether EMT itself or specific EMT
regulators play causal roles in these properties. Here we identify an
EMT-inducing transcription factor, zinc finger E-box binding homeobox 1 (ZEB1),
as a regulator of radiosensitivity and DNA damage response (DDR). Radioresistant
subpopulations of breast cancer cells derived from ionizing radiation exhibit
hyperactivation of ATM and upregulation of ZEB1, and ZEB1 promotes tumor cell
radioresistance in vitro and in vivo.
Mechanistically, ATM kinase phosphorylates and stabilizes ZEB1 in response to
DNA damage, and ZEB1 in turn directly interacts with USP7 and enhances its
ability to deubiquitinate and stabilize CHK1, thereby promoting homologous
recombination-dependent DNA repair and resistance to radiation. These findings
identify ZEB1 as an ATM substrate linking ATM to CHK1 and as the mechanism
underlying the association between EMT and radioresistance.
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340
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Rodríguez JA. Interplay between nuclear transport and ubiquitin/SUMO modifications in the regulation of cancer-related proteins. Semin Cancer Biol 2014; 27:11-9. [DOI: 10.1016/j.semcancer.2014.03.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/22/2014] [Accepted: 03/25/2014] [Indexed: 11/25/2022]
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341
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Thirumurthi U, Shen J, Xia W, LaBaff AM, Wei Y, Li CW, Chang WC, Chen CH, Lin HK, Yu D, Hung MC. MDM2-mediated degradation of SIRT6 phosphorylated by AKT1 promotes tumorigenesis and trastuzumab resistance in breast cancer. Sci Signal 2014; 7:ra71. [PMID: 25074979 DOI: 10.1126/scisignal.2005076] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sirtuin 6 (SIRT6) is associated with longevity and is also a tumor suppressor. Identification of molecular regulators of SIRT6 might enable its activation therapeutically in cancer patients. In various breast cancer cell lines, we found that SIRT6 was phosphorylated at Ser(338) by the kinase AKT1, which induced the interaction and ubiquitination of SIRT6 by MDM2, targeting SIRT6 for protease-dependent degradation. The survival of breast cancer patients positively correlated with the abundance of SIRT6 and inversely correlated with the phosphorylation of SIRT6 at Ser(338). In a panel of breast tumor biopsies, SIRT6 abundance inversely correlated with the abundance of phosphorylated AKT. Inhibiting AKT or preventing SIRT6 phosphorylation by mutating Ser(338) prevented the degradation of SIRT6 mediated by MDM2, suppressed the proliferation of breast cancer cells in culture, and inhibited the growth of breast tumor xenografts in mice. Overexpressing MDM2 decreased the abundance of SIRT6 in cells, whereas overexpressing an E3 ligase-deficient MDM2 or knocking down endogenous MDM2 increased SIRT6 abundance. Trastuzumab (known as Herceptin) is a drug that targets a specific receptor common in some breast cancers, and knocking down SIRT6 increased the survival of a breast cancer cell exposed to trastuzumab. Overexpression of a nonphosphorylatable SIRT6 mutant increased trastuzumab sensitivity in a resistant breast cancer cell line. Thus, stabilizing SIRT6 may be a clinical strategy for overcoming trastuzumab resistance in breast cancer patients.
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Affiliation(s)
- Umadevi Thirumurthi
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Jia Shen
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Weiya Xia
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Adam M LaBaff
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Yongkun Wei
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chia-Wei Li
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Wei-Chao Chang
- Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan
| | - Chung-Hsuan Chen
- Genomics Research Center, Academia Sinica, Nankang, Taipei 106, Taiwan. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan. Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Hui-Kuan Lin
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Dihua Yu
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA. Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan. Department of Biotechnology, Asia University, Taichung 413, Taiwan.
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342
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Han L, Yang J, Wang X, Wu Q, Yin S, Li Z, Zhang J, Xing Y, Chen Z, Tsun A, Li D, Piccioni M, Zhang Y, Guo Q, Jiang L, Bao L, Lv L, Li B. The E3 deubiquitinase USP17 is a positive regulator of retinoic acid-related orphan nuclear receptor γt (RORγt) in Th17 cells. J Biol Chem 2014; 289:25546-55. [PMID: 25070893 DOI: 10.1074/jbc.m114.565291] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Stable retinoic acid-related orphan nuclear receptor γt (RORγt) expression is pivotal for the development and function of Th17 cells. Here we demonstrate that expression of the transcription factor RORγt can be regulated through deubiquitination, which prevents proteasome-mediated degradation. We establish that USP17 stabilizes RORγt protein expression by reducing RORγt polyubiquitination at its Lys-360 residue. In contrast, knockdown of endogenous USP17 in Th17 cells resulted in decreased RORγt protein levels and down-regulation of Th17-related genes. Furthermore, USP17 expression was up-regulated in CD4(+) T cells from systemic lupus erythematosus patients. Our data reveal a molecular mechanism in which RORγt expression in Th17 cells can be positively regulated by USP17, thereby modulating Th17 cell functions.
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Affiliation(s)
- Lei Han
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Jing Yang
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Xiuwen Wang
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Qingsi Wu
- the Department of Immunology, Anhui Medical University, Hefei 230032, China
| | - Shuying Yin
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Zhiyuan Li
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Jing Zhang
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Yue Xing
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Zuojia Chen
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China
| | - Andy Tsun
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Dan Li
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Miranda Piccioni
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Yu Zhang
- the Department of Obstetrics and Gynecology and
| | - Qiang Guo
- Department of Rheumatology, Renji Hospital, Shanghai Jiao Tong University Medical School, 1630 Dongfang Road, Shanghai 200127, China
| | - Lindi Jiang
- the Department of Rheumatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China, and
| | - Liming Bao
- the Department of Pathology, Dartmouth-Hitchcock Medical Center, Geisel School of Medicine, Dartmouth College, Lebanon, New Hampshire 03756
| | - Ling Lv
- From the Division of Rheumatology, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China,
| | - Bin Li
- the Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200032, China,
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343
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The deubiquitinating enzyme USP17 is associated with non-small cell lung cancer (NSCLC) recurrence and metastasis. Oncotarget 2014; 4:1836-43. [PMID: 24123619 PMCID: PMC3858568 DOI: 10.18632/oncotarget.1282] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
USP17 is a cell cycle regulated deubiquitinating enzyme that is highly expressed in tumor-derived cell lines and has an established role in cell proliferation and chemotaxis. This is the first study to examine the clinical significance of USP17 expression in non-small cell lung cancer (NSCLC). USP17 was overexpressed in both squamous and adenocarcinoma NSCLC tissue. Patients with USP17 positive tumors had significantly reduced recurrence-free survival than patients with USP17 negative tumors. Moreover, USP17 was more highly expressed in patients with recurrence of disease at distant sites, suggesting that USP17 levels may correlate with NSCLC distant metastases. Overall, these findings establish USP17 as a potentially valuable novel biomarker for metastatic lung cancer.
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344
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Shindyapina AV, Petrunia IV, Komarova TV, Sheshukova EV, Kosorukov VS, Kiryanov GI, Dorokhov YL. Dietary methanol regulates human gene activity. PLoS One 2014; 9:e102837. [PMID: 25033451 PMCID: PMC4102594 DOI: 10.1371/journal.pone.0102837] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 06/23/2014] [Indexed: 12/02/2022] Open
Abstract
Methanol (MeOH) is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of MeOH to formaldehyde (FA), which is toxic. Our recent genome-wide analysis of the mouse brain demonstrated that an increase in endogenous MeOH after ADH inhibition led to a significant increase in the plasma MeOH concentration and a modification of mRNA synthesis. These findings suggest endogenous MeOH involvement in homeostasis regulation by controlling mRNA levels. Here, we demonstrate directly that study volunteers displayed increasing concentrations of MeOH and FA in their blood plasma when consuming citrus pectin, ethanol and red wine. A microarray analysis of white blood cells (WBC) from volunteers after pectin intake showed various responses for 30 significantly differentially regulated mRNAs, most of which were somehow involved in the pathogenesis of Alzheimer's disease (AD). There was also a decreased synthesis of hemoglobin mRNA, HBA and HBB, the presence of which in WBC RNA was not a result of red blood cells contamination because erythrocyte-specific marker genes were not significantly expressed. A qRT-PCR analysis of volunteer WBCs after pectin and red wine intake confirmed the complicated relationship between the plasma MeOH content and the mRNA accumulation of both genes that were previously identified, namely, GAPDH and SNX27, and genes revealed in this study, including MME, SORL1, DDIT4, HBA and HBB. We hypothesized that human plasma MeOH has an impact on the WBC mRNA levels of genes involved in cell signaling.
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Affiliation(s)
- Anastasia V. Shindyapina
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
- N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Igor V. Petrunia
- N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Tatiana V. Komarova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
- N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | | | | | - Gleb I. Kiryanov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
| | - Yuri L. Dorokhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
- N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
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345
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Sun XX, Dai MS. Deubiquitinating enzyme regulation of the p53 pathway: A lesson from Otub1. World J Biol Chem 2014; 5:75-84. [PMID: 24920999 PMCID: PMC4050119 DOI: 10.4331/wjbc.v5.i2.75] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/11/2014] [Accepted: 03/14/2014] [Indexed: 02/05/2023] Open
Abstract
Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes (DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme (E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.
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346
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Pessina F, Lowndes NF. The RSF1 histone-remodelling factor facilitates DNA double-strand break repair by recruiting centromeric and Fanconi Anaemia proteins. PLoS Biol 2014; 12:e1001856. [PMID: 24800743 PMCID: PMC4011676 DOI: 10.1371/journal.pbio.1001856] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/28/2014] [Indexed: 01/18/2023] Open
Abstract
ATM is a central regulator of the cellular responses to DNA double-strand breaks (DSBs). Here we identify a biochemical interaction between ATM and RSF1 and we characterise the role of RSF1 in this response. The ATM-RSF1 interaction is dependent upon both DSBs and ATM kinase activity. Together with SNF2H/SMARCA5, RSF1 forms the RSF chromatin-remodelling complex. Although RSF1 is specific to the RSF complex, SNF2H/SMARCA5 is a catalytic subunit of several other chromatin-remodelling complexes. Although not required for checkpoint signalling, RSF1 is required for efficient repair of DSBs via both end-joining and homology-directed repair. Specifically, the ATM-dependent recruitment to sites of DSBs of the histone fold proteins CENPS/MHF1 and CENPX/MHF2, previously identified at centromeres, is RSF1-dependent. In turn these proteins recruit and regulate the mono-ubiquitination of the Fanconi Anaemia proteins FANCD2 and FANCI. We propose that by depositing CENPS/MHF1 and CENPX/MHF2, the RSF complex either directly or indirectly contributes to the reorganisation of chromatin around DSBs that is required for efficient DNA repair.
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Affiliation(s)
- Fabio Pessina
- Genome Stability Laboratory, Centre for Chromosome Biology, School of Natural Science, National University of Ireland Galway, Ireland
| | - Noel F. Lowndes
- Genome Stability Laboratory, Centre for Chromosome Biology, School of Natural Science, National University of Ireland Galway, Ireland
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347
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Park J, Yang S, Yu K, Ka S, Lee S, Seol J, Jeon Y, Chung C. Modification of PCNA by ISG15 Plays a Crucial Role in Termination of Error-Prone Translesion DNA Synthesis. Mol Cell 2014; 54:626-38. [DOI: 10.1016/j.molcel.2014.03.031] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/14/2014] [Accepted: 03/10/2014] [Indexed: 12/15/2022]
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348
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Stintzing S, Lenz HJ. Molecular pathways: turning proteasomal protein degradation into a unique treatment approach. Clin Cancer Res 2014; 20:3064-70. [PMID: 24756373 DOI: 10.1158/1078-0432.ccr-13-3175] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cancer treatment regimens have evolved from single cytotoxic substances affecting all proliferative tissues toward antibodies and kinase inhibitors targeting tumor-specific pathways. Treatment efficacy and cancer survival have improved overall, and side effects have become less frequent. The ubiquitin-proteasome system-mediated proteasomal protein degradation is the most critical pathway to regulate the quantity of signal proteins involved in carcinogenesis and tumor progression. These processes are, as well as protein recycling, highly regulated and offer targets for biomarker and drug development. Unspecific proteasome inhibitors such as bortezomib and carfilzomib have shown clinical efficacy and are approved for clinical use. Inhibitors of more substrate-specific enzymes of degradation processes are being developed and are now in early clinical trials. The novel compounds focus on the degradation of key regulatory proteins such as p53, p27(Kip1), and ß-catenin, and inhibitors specific for growth factor receptor kinase turnover are in preclinical testing.
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Affiliation(s)
- Sebastian Stintzing
- Authors' Affiliation: USC/Norris Comprehensive Cancer Center, Keck School of Medicine, Sharon Carpenter Laboratory, Los Angeles, California
| | - Heinz-Josef Lenz
- Authors' Affiliation: USC/Norris Comprehensive Cancer Center, Keck School of Medicine, Sharon Carpenter Laboratory, Los Angeles, California
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349
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Yang Q, Ou C, Liu M, Xiao W, Wen C, Sun F. NRAGE promotes cell proliferation by stabilizing PCNA in a ubiquitin-proteasome pathway in esophageal carcinomas. Carcinogenesis 2014; 35:1643-51. [PMID: 24710624 DOI: 10.1093/carcin/bgu084] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neurotrophin receptor-interacting melanoma antigen-encoding gene homolog (NRAGE) is generally recognized as a tumor suppressor as it induces cell apoptosis and suppresses cell metastasis. However, it has recently been reported that NRAGE is overexpressed in lung cancer, melanoma and colon cancer, implicating a complicated role of NRAGE as we have expected. In the study, we aim to elucidate the functional roles and molecular mechanisms of NRAGE in esophageal carcinoma. We found that both NRAGE mRNA and protein were significantly overexpressed in esophageal tumor tissues. Consistently, both in vivo and in vitro analyses demonstrated that knockdown of NRAGE apparently inhibited cell growth, and cell cycle analysis further demonstrated that NRAGE knockdown cells were mainly arrested in G2M cell phase, accompanied with an apparent reduction of S phase. In the process of exploring molecular mechanisms, we found that either knockdown in vitro or knockout in vivo of NRAGE reduced proliferating cell nuclear antigen (PCNA) protein, expression of which could completely rescue the inhibited proliferation in NRAGE defective cells. Furthermore, NRAGE physically interacted with PCNA in esophageal cancer cells through DNA polymerase III subunit, and knockdown of NRAGE facilitated PCNA K48-linked polyubiquitination, leading PCNA to the proteasome-dependent degradation and a ubiquitin-specific protease USP10 was identified to be a key regulator in the process of K48 polyubiquitination in NRAGE-deleted cells. In conclusion, our study highlights a unique role of NRAGE and implies that NRAGE is likely to be an attractive oncotarget in developing novel genetic anticancer therapeutic strategies for esophageal squamous cell carcinomas.
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Affiliation(s)
- Qingyuan Yang
- Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
| | - Chao Ou
- Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China
| | - Mei Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and
| | - Weifan Xiao
- The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
| | - Chuanjun Wen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and
| | - Fenyong Sun
- Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
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350
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The chemosensitivity of testicular germ cell tumors. Cell Oncol (Dordr) 2014; 37:79-94. [PMID: 24692098 DOI: 10.1007/s13402-014-0168-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2014] [Indexed: 12/13/2022] Open
Abstract
Although rare cancers overall, testicular germ cell tumors (TGCTs) are the most common type of cancer in young males below 40 years of age. Both subtypes of TGCTs, i.e., seminomas and non-seminomas, are highly curable and the majority of even metastatic patients may expect to be cured. These high cure rates are not due to the indolent nature of these cancers, but rather to their sensitivity to chemotherapy (and for seminomas to radiotherapy). The delineation of the cause of chemosensitivity at the molecular level is of paramount importance, because it may provide insights into the minority of TGCTs that are chemo-resistant and, thereby, provide opportunities for specific therapeutic interventions aimed at reverting them to chemosensitivity. In addition, delineation of the molecular basis of TGCT chemo-sensitivity may be informative for the cause of chemo-resistance of other more common types of cancer and, thus, may create new therapeutic leads. p53, a frequently mutated tumor suppressor in cancers in general, is not mutated in TGCTs, a fact that has implications for their chemo-sensitivity. Oct4, an embryonic transcription factor, is uniformly expressed in the seminoma and embryonic carcinoma components of non-seminomas, and its interplay with p53 may be important in the chemotherapy response of these tumors. This interplay, together with other features of TGCTs such as the gain of genetic material from the short arm of chromosome 12 and the association with disorders of testicular development, will be discussed in this paper and integrated in a unifying hypothesis that may explain their chemo-sensitivity.
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