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Qin S, Kitty I, Hao Y, Zhao F, Kim W. Maintaining Genome Integrity: Protein Kinases and Phosphatases Orchestrate the Balancing Act of DNA Double-Strand Breaks Repair in Cancer. Int J Mol Sci 2023; 24:10212. [PMID: 37373360 DOI: 10.3390/ijms241210212] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most lethal DNA damages which lead to severe genome instability. Phosphorylation is one of the most important protein post-translation modifications involved in DSBs repair regulation. Kinases and phosphatases play coordinating roles in DSB repair by phosphorylating and dephosphorylating various proteins. Recent research has shed light on the importance of maintaining a balance between kinase and phosphatase activities in DSB repair. The interplay between kinases and phosphatases plays an important role in regulating DNA-repair processes, and alterations in their activity can lead to genomic instability and disease. Therefore, study on the function of kinases and phosphatases in DSBs repair is essential for understanding their roles in cancer development and therapeutics. In this review, we summarize the current knowledge of kinases and phosphatases in DSBs repair regulation and highlight the advancements in the development of cancer therapies targeting kinases or phosphatases in DSBs repair pathways. In conclusion, understanding the balance of kinase and phosphatase activities in DSBs repair provides opportunities for the development of novel cancer therapeutics.
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Affiliation(s)
- Sisi Qin
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Ichiwa Kitty
- Department of Integrated Biomedical Science, Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Chungcheongnam-do, Republic of Korea
| | - Yalan Hao
- Analytical Instrumentation Center, Hunan University, Changsha 410082, China
| | - Fei Zhao
- College of Biology, Hunan University, Changsha 410082, China
| | - Wootae Kim
- Department of Integrated Biomedical Science, Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Chungcheongnam-do, Republic of Korea
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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Ratushnyy AY, Rudimova YV, Buravkova LB. Alteration of Hypoxia-Associated Gene Expression in Replicatively Senescent Mesenchymal Stromal Cells under Physiological Oxygen Level. BIOCHEMISTRY (MOSCOW) 2019; 84:263-271. [PMID: 31221064 DOI: 10.1134/s0006297919030088] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mesenchymal stromal cells (MSCs) are a population of adult stem cells that modulate functional state of neighboring tissues. During cell aging, the biological activity of MSC changes, which may affect tissue homeostasis. It is known that reducing the oxygen level in vitro to physiological values typical to a particular cell niche leads to attenuation of some morphological and functional changes associated with aging. This work aimed to study gene expression in MSCs involved in response to physiological hypoxia using a replicative aging model under physiological (5%) and atmospheric (20%) oxygen in cultures. Our results show that significant reduction of proliferative activity of MSCs is observed after 20 passages (~50 cell generations). Regardless of the oxygen, in senescent cells PKM2, SERPINE1, and VEGFA were upregulated while ANKRD37, DDIT4, HIF1A, and TXNIP were downregulated. Also, ADORA2B, BNIPL, CCNG2, EGLN1, MAP3K1, MXI1, and P4HA1 were downregulated under hypoxia. The effect of oxygen was more pronounced at earlier passages both on the cellular and transcription levels. Irrespective of the passage, genes ANGPTL4, GYS1, PKM2, SERPINE1, and TP53 were downregulated under hypoxia. Also, decreased expression was observed for ADM, F10, HMOX1, P4HB, PFKL, SLC16A3 in earlier passages, and for HK2 - in later passages. Upregulation was only observed for ANKRD37, both at early and late cultures.
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Affiliation(s)
- A Yu Ratushnyy
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia
| | - Yu V Rudimova
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia
| | - L B Buravkova
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia.
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Zhang L, Lu P, Yan L, Yang L, Wang Y, Chen J, Dai J, Li Y, Kang Z, Bai T, Xi Y, Xu J, Sun G, Yang T. MRPL35 Is Up-Regulated in Colorectal Cancer and Regulates Colorectal Cancer Cell Growth and Apoptosis. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:1105-1120. [PMID: 30862482 DOI: 10.1016/j.ajpath.2019.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 01/28/2019] [Accepted: 02/05/2019] [Indexed: 02/07/2023]
Abstract
Mitochondrial ribosome proteins (MRPs), which are encoded by the nuclear genomic DNA, are important for mitochondrial-encoded protein synthesis and mitochondrial function. Emerging evidence suggests that several MRPs also exhibit important extra-mitochondrial functions, such as involvement in apoptosis, protein biosynthesis, and signal transduction. In this study, we demonstrate a significant role of MRP L35 (MRPL35) in colorectal cancer (CRC). The expression of MRPL35 was higher in CRC tissues than in matched cancer-adjacent tissues and higher in CRC cells than in normal mucosal epithelial cells. Higher MRPL35 expression in CRC tissue correlated with shorter overall survival for CRC patients. In vitro, down-regulation of MRPL35 led to increased production of reactive oxygen species (ROS) together with DNA damage, loss of cell proliferation, G2/M arrest, a decrease in mitochondrial membrane potential, apoptosis, and autophagy induction. MRPL35 knockdown inhibited tumor proliferation in a CRC xenograft nude mouse model. Furthermore, overexpression of MRPL35 or treatment of cells with the ROS scavenger, N-acetyl cysteine, abrogated ROS production, cell cycle arrest, and apoptosis in vitro. These findings suggest that MRPL35 plays an essential role in the development of CRC and may be a potential therapeutic target for CRC.
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Affiliation(s)
- Litao Zhang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Peifen Lu
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Lihong Yan
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Lijun Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yutao Wang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Junjun Chen
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Jie Dai
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Yahui Li
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Zhiming Kang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China
| | - Tao Bai
- Department of Pathology, First Affiliated Hospital of Shanxi Medical University, Taiyuan, China
| | - Yanfeng Xi
- Department of Pathology, Shanxi Provincial Cancer Hospital, Taiyuan, China
| | - Jun Xu
- Department of General Surgery, Shanxi Grand Hospital, Taiyuan, China
| | - Gongqin Sun
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China; Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island.
| | - Tao Yang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China.
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Kidane D. Molecular Mechanisms of H. pylori-Induced DNA Double-Strand Breaks. Int J Mol Sci 2018; 19:ijms19102891. [PMID: 30249046 PMCID: PMC6213211 DOI: 10.3390/ijms19102891] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/11/2018] [Accepted: 09/21/2018] [Indexed: 12/17/2022] Open
Abstract
Infections contribute to carcinogenesis through inflammation-related mechanisms. H. pylori infection is a significant risk factor for gastric carcinogenesis. However, the molecular mechanism by which H. pylori infection contributes to carcinogenesis has not been fully elucidated. H. pylori-associated chronic inflammation is linked to genomic instability via reactive oxygen and nitrogen species (RONS). In this article, we summarize the current knowledge of H. pylori-induced double strand breaks (DSBs). Furthermore, we provide mechanistic insight into how processing of oxidative DNA damage via base excision repair (BER) leads to DSBs. We review recent studies on how H. pylori infection triggers NF-κB/inducible NO synthase (iNOS) versus NF-κB/nucleotide excision repair (NER) axis-mediated DSBs to drive genomic instability. This review discusses current research findings that are related to mechanisms of DSBs and repair during H. pylori infection.
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Affiliation(s)
- Dawit Kidane
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. R1800, Austin, TX 78723, USA.
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Chang BH, Johnson K, LaTocha D, Rowley JSJ, Bryant J, Burke R, Smith RL, Loriaux M, Müschen M, Mullighan C, Druker BJ, Tyner JW. YM155 potently kills acute lymphoblastic leukemia cells through activation of the DNA damage pathway. J Hematol Oncol 2015; 8:39. [PMID: 25895498 PMCID: PMC4408565 DOI: 10.1186/s13045-015-0132-6] [Citation(s) in RCA: 29] [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: 10/30/2014] [Accepted: 03/26/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Novel-targeted therapies are in rapid development for the treatment of acute lymphoblastic leukemia (ALL) to overcome resistance and decrease toxicity. Survivin, a member of the inhibitor of apoptosis gene family and chromosome passenger complex, is critical in a variety of human cancers, including ALL. A well-established suppressor of survivin has been the small molecule, YM155. Reports are identifying other mechanisms of action for YM155. Therefore, we sought to investigate the mode of action and role of YM155 for therapeutic use in the context of ALL. METHODS Primary ALL samples and ALL cell lines were interrogated with YM155 to identify drug sensitivity. Ph(+)ALL harboring the BCR-ABL1 oncogene were tested for any interaction with YM155 and the multi-kinase inhibitor dasatinib. Representative ALL cell lines were tested to identify the response to YM155 using standard biochemical assays as well as RNA expression and phosphorylation arrays. RESULTS ALL samples exhibited significant sensitivity to YM155, and an additive response was observed with dasatinib in the setting of Ph(+)ALL. ALL cells were more sensitive to YM155 during S phase during DNA replication. YM155 activates the DNA damage pathway leading to phosphorylation of Chk2 and H2AX. Interestingly, screening of primary patient samples identified unique and exquisite YM155 sensitivity in some but not all ALL specimens. CONCLUSION These results are the first to have screened a large number of primary patient leukemic samples to identify individual variations of response to YM155. Our studies further support that YM155 in ALL induces DNA damage leading to S phase arrest. Finally, only subsets of ALL have exquisite sensitivity to YM155 presumably through both suppression of survivin expression and activation of the DNA damage pathway underscoring its potential for therapeutic development.
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Affiliation(s)
- Bill H Chang
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Oregon Health & Science University, Portland, OR, 97239, USA.
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
| | - Kara Johnson
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
| | | | | | - Jade Bryant
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
| | - Russell Burke
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
| | | | - Marc Loriaux
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
- Department of Pathology, Oregon Health & Science University, Portland, OR, 97239, USA.
| | - Markus Müschen
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA, USA.
| | - Charles Mullighan
- Department of Oncology, St Jude Children's Research Hospital and University of Tennessee Health Science Center, Memphis, TN, 38105, USA.
| | - Brian J Druker
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
- Howard Hughes Medical Institute, Portland, OR, 97239, USA.
| | - Jeffrey W Tyner
- OHSU Knight Cancer Institute, Portland, OR, 97239, USA.
- Department Cell & Developmental Biology, Oregon Health & Science University, Portland, OR, 97239, USA.
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Neri P, Bahlis NJ. Genomic instability in multiple myeloma: mechanisms and therapeutic implications. Expert Opin Biol Ther 2013; 13 Suppl 1:S69-82. [PMID: 23782016 DOI: 10.1517/14712598.2013.814637] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Clonal plasma cells in multiple myeloma (MM) are typified by their nearly universal aneuploidy and the presence of recurrent chromosomal aberrations reflecting their chromosomal instability. Multiple myeloma is also recognized to be heterogeneous with distinct molecular subgroups. Deep genome sequencing studies have recently revealed an even wider heterogeneity and genomic instability with the identification of a complex mutational landscape and a branching pattern of clonal evolution. AREAS COVERED Despite the lack of full understanding of the exact mechanisms driving the genomic instability in MM, recent observations have correlated these abnormalities with impairments in the DNA damage repair machinery as well as epigenetic changes. These mechanisms and the resulting therapeutic implications will be the subject of this review. EXPERT OPINION By providing growth advantage of the fittest clone and promoting the acquisition of drug resistance, genomic instability is unarguably beneficial to MM cells, however, it may also well be its Achilles heal by creating exploitable vulnerabilities. As such, targeting presumptive DNA repair defects and other oncogenic addictions represent a promising area of clinical investigation. In particular, by inducing gene or pathway dependencies not present in normal cells, genomic instability can generate targets of contextual synthetic lethality in MM cells.
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Affiliation(s)
- Paola Neri
- University of Calgary, Division of Hematology and Bone Marrow Transplant, Hospital Drive NW, Calgary, AB T2N4N1, Canada
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Abstract
Radiation therapy methods have evolved remarkably in recent years which have resulted in more effective local tumor control with negligible toxicity of surrounding normal tissues. However, local recurrence and distant metastasis often occur following radiation therapy mostly due to the development of radioresistance through the deregulation of the cell cycle, apoptosis, and inhibition of DNA damage repair mechanisms. Over the last decade, extensive progress in radiotherapy and gene therapy combinatorial approaches has been achieved to overcome resistance of tumor cells to radiation. In this review, we summarize the results from experimental cancer therapy studies on the combination of radiation therapy and gene therapy.
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APRIN is a cell cycle specific BRCA2-interacting protein required for genome integrity and a predictor of outcome after chemotherapy in breast cancer. EMBO J 2012; 31:1160-76. [PMID: 22293751 DOI: 10.1038/emboj.2011.490] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 12/15/2011] [Indexed: 12/19/2022] Open
Abstract
Mutations in BRCA2 confer an increased risk of cancer development, at least in part because the BRCA2 protein is required for the maintenance of genomic integrity. Here, we use proteomic profiling to identify APRIN (PDS5B), a cohesion-associated protein, as a BRCA2-associated protein. After exposure of cells to hydroxyurea or aphidicolin, APRIN and other cohesin components associate with BRCA2 in early S-phase. We demonstrate that APRIN expression is required for the normal response to DNA-damaging agents, the nuclear localisation of RAD51 and BRCA2 and efficient homologous recombination. The clinical significance of these findings is indicated by the observation that the BRCA2/APRIN interaction is compromised by BRCA2 missense variants of previously unknown significance and that APRIN expression levels are associated with histological grade in breast cancer and the outcome of breast cancer patients treated with DNA-damaging chemotherapy.
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10
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Deorukhkar A, Krishnan S. Targeting inflammatory pathways for tumor radiosensitization. Biochem Pharmacol 2010; 80:1904-14. [PMID: 20599771 PMCID: PMC3090731 DOI: 10.1016/j.bcp.2010.06.039] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/19/2010] [Accepted: 06/22/2010] [Indexed: 12/16/2022]
Abstract
Although radiation therapy (RT) is an integral component of treatment of patients with many types of cancer, inherent and/or acquired resistance to the cytotoxic effects of RT is increasingly recognized as a significant impediment to effective cancer treatment. Inherent resistance is mediated by constitutively activated oncogenic, proliferative and anti-apoptotic proteins/pathways whereas acquired resistance refers to transient induction of proteins/pathways following radiation exposure. To realize the full potential of RT, it is essential to understand the signaling pathways that mediate inducible radiation resistance, a poorly characterized phenomenon, and identify druggable targets for radiosensitization. Ionizing radiation induces a multilayered signaling response in mammalian cells by activating many pro-survival pathways that converge to transiently activate a few important transcription factors (TFs), including nuclear factor kappa B (NF-κB) and signal transducers and activators of transcription (STATs), the central mediators of inflammatory and carcinogenic signaling. Together, these TFs activate a wide spectrum of pro-survival genes regulating inflammation, anti-apoptosis, invasion and angiogenesis pathways, which confer tumor cell radioresistance. Equally, radiation-induced activation of pro-inflammatory cytokine network (including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α) has been shown to mediate symptom burden (pain, fatigue, local inflammation) in cancer patients. Thus, targeting radiation-induced inflammatory pathways may exert a dual effect of accentuating the tumor radioresponse and reducing normal tissue side-effects, thereby increasing the therapeutic window of cancer treatment. We review recent data demonstrating the pivotal role played by inflammatory pathways in cancer progression and modulation of radiation response.
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Affiliation(s)
- Amit Deorukhkar
- Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Sunil Krishnan
- Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
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11
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Samet JM, Tal TL. Toxicological disruption of signaling homeostasis: tyrosine phosphatases as targets. Annu Rev Pharmacol Toxicol 2010; 50:215-35. [PMID: 20055703 DOI: 10.1146/annurev.pharmtox.010909.105841] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The protein tyrosine phosphatases (PTPs) consist of a diverse group of enzymes whose activity opposes that of the tyrosine kinases. As such, the PTPs have critical roles in maintaining signaling quiescence in resting cells and in restoring homeostasis by effecting signal termination. Interest in these enzymes has increased in recent years following the discovery that the activity of PTPs is modulated through redox mechanisms during signaling. The molecular features that enable redox regulation of PTPs during physiological signaling also render them highly susceptible to oxidative and electrophilic inactivation by a broad spectrum of structurally disparate xenobiotic compounds. The loss of PTP activity results in a profound disregulation of protein phosphotyrosine metabolism, leading to widespread and persistent activation of signaling cascades in the cell.
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Affiliation(s)
- James M Samet
- U.S. Environmental Protection Agency, Chapel Hill, North Carolina, USA.
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12
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Moon SH, Lin L, Zhang X, Nguyen TA, Darlington Y, Waldman AS, Lu X, Donehower LA. Wild-type p53-induced phosphatase 1 dephosphorylates histone variant gamma-H2AX and suppresses DNA double strand break repair. J Biol Chem 2010; 285:12935-47. [PMID: 20118229 DOI: 10.1074/jbc.m109.071696] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In response to DNA double strand breaks, the histone variant H2AX at the break site is phosphorylated at serine 139 by DNA damage sensor kinases such as ataxia telangiectasia-mutated, forming gamma-H2AX. This phosphorylation event is critical for sustained recruitment of other proteins to repair the break. After repair, restoration of the cell to a prestress state is associated with gamma-H2AX dephosphorylation and dissolution of gamma-H2AX-associated damage foci. The phosphatases PP2A and PP4 have previously been shown to dephosphorylate gamma-H2AX. Here, we demonstrate that the wild-type p53-induced phosphatase 1 (WIP1) also dephosphorylates gamma-H2AX at serine 139 in vitro and in vivo. Overexpression of WIP1 reduces formation of gamma-H2AX foci in response to ionizing and ultraviolet radiation and blocks recruitment of MDC1 (mediator of DNA damage checkpoint 1) and 53BP1 (p53 binding protein 1) to DNA damage foci. Finally, these inhibitory effects of WIP1 on gamma-H2AX are accompanied by WIP1 suppression of DNA double strand break repair. Thus, WIP1 has a homeostatic role in reversing the effects of ataxia telangiectasia-mutated phosphorylation of H2AX.
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Affiliation(s)
- Sung-Hwan Moon
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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Wang C, Jurk D, Maddick M, Nelson G, Martin-Ruiz C, von Zglinicki T. DNA damage response and cellular senescence in tissues of aging mice. Aging Cell 2009; 8:311-23. [PMID: 19627270 DOI: 10.1111/j.1474-9726.2009.00481.x] [Citation(s) in RCA: 490] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The impact of cellular senescence onto aging of organisms is not fully clear, not at least because of the scarcity of reliable data on the mere frequency of senescent cells in aging tissues. Activation of a DNA damage response including formation of DNA damage foci containing activated H2A.X (gamma-H2A.X) at either uncapped telomeres or persistent DNA strand breaks is the major trigger of cell senescence. Therefore, gamma-H2A.X immunohistochemistry (IHC) was established by us as a reliable quantitative indicator of senescence in fibroblasts in vitro and in hepatocytes in vivo and the age dependency of DNA damage foci accumulation in ten organs of C57Bl6 mice was analysed over an age range from 12 to 42 months. There were significant increases with age in the frequency of foci-containing cells in lung, spleen, dermis, liver and gut epithelium. In liver, foci-positive cells were preferentially found in the centrilobular area, which is exposed to higher levels of oxidative stress. Foci formation in the intestine was restricted to the crypts. It was not associated with either apoptosis or hyperproliferation. That telomeres shortened with age in both crypt and villus enterocytes, but telomeres in the crypt epithelium were longer than those in villi at all ages were confirmed by us. Still, there was no more than random co-localization between gamma-H2A.X foci and telomeres even in crypts from very old mice, indicating that senescence in the crypt enterocytes is telomere independent. The results suggest that stress-dependent cell senescence could play a causal role for aging of mice.
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Affiliation(s)
- Chunfang Wang
- Ageing Research Laboratories, Institute for Ageing and Health and Center for Integrated Systems Biology of Ageing and Nutrition (CISBAN), Newcastle University, Newcastle upon Tyne NE4 6BE, UK
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Grosjean-Raillard J, Tailler M, Adès L, Perfettini JL, Fabre C, Braun T, De Botton S, Fenaux P, Kroemer G. ATM mediates constitutive NF-kappaB activation in high-risk myelodysplastic syndrome and acute myeloid leukemia. Oncogene 2008; 28:1099-109. [PMID: 19079347 DOI: 10.1038/onc.2008.457] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The anti-apoptotic transcription factor nuclear factor-kappaB (NF-kappaB) is constitutively activated in CD34(+) myeloblasts from high-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) patients. Inhibition of NF-kappaB by suppressing the canonical NF-kappaB activation pathway, for instance by knockdown of the three subunits of the inhibitor of NF-kappaB (I kappaB) kinase (IKK) complex (IKK1, IKK2 and NEMO) triggers apoptosis in such cells. Here, we show that an MDS/AML model cell line exhibits a constitutive interaction, within the nucleus, of activated, S1981-phosphorylated ataxia telangiectasia mutated (ATM) with NEMO. Inhibition of ATM with two distinct pharmacological inhibitors suppressed the activating autophosphorylation of ATM, blocked the interaction of ATM and NEMO, delocalized NEMO as well as another putative NF-kappaB activator, PIDD, from the nucleus, abolished the activating phosphorylation of the catalytic proteins of the IKK complex (IKK1/2 on serines 176/180), enhanced the expression of I kappaB alpha and caused the relocalization of NF-kappaB from the nucleus to the cytoplasm, followed by apoptosis. Knockdown of ATM with small-interfering RNAs had a similar effect that could not be enhanced by knockdown of NEMO, PIDD and the p65 NF-kappaB subunit, suggesting that an ATM inhibition/depletion truly induced apoptosis through inhibition of the NF-kappaB system. Pharmacological inhibition of ATM also induced the nucleocytoplasmic relocalization of p65 in malignant myeloblasts purified from patients with high-risk MDS or AML, correlating with the induction of apoptosis. Altogether, these results support the contention that constitutively active ATM accounts for the activation of NF-kappaB in high-risk MDS and AML.
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15
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Razvi MH, Peng D, Dar AA, Powell SM, Frierson HF, Moskaluk CA, Washington K, El‐Rifai W. Transcriptional oncogenomic hot spots in Barrett's adenocarcinomas: serial analysis of gene expression. Genes Chromosomes Cancer 2007; 46:914-28. [PMID: 17636545 PMCID: PMC7165894 DOI: 10.1002/gcc.20479] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Serial analysis of gene expression (SAGE) provides quantitative and comprehensive expression profiling in a given cell population. In our efforts to define gene expression alterations in Barrett's-related adenocarcinomas (BA), we produced eight SAGE libraries and obtained a total of 457,894 expressed tags with 32,035 (6.9%) accounting for singleton tags. The tumor samples produced an average of 71,804 tags per library, whereas normal samples produced an average of 42,669 tags per library. Our libraries contained 67,200 unique tags representing 16,040 known gene symbols. Five hundred and sixty-eight unique tags were differentially expressed between BAs and normal tissue samples (at least twofold; P<or=0.05), 395 of these matched to known genes. Interestingly, the distribution of altered genes was not uniform across the human genome. Overexpressed genes tended to cluster in well-defined hot spots located in certain chromosomes. For example, chromosome 19 had 26 overexpressed genes, of which 18 mapped to 19q13. Using the gene ontology approach for functional classification of genes, we identified several groups that are relevant to carcinogenesis. We validated the SAGE results of five representative genes (ANPEP, ECGF1, PP1201, EIF5A1, and GKN1) using quantitative real-time reverse-transcription PCR on 31 BA samples and 26 normal samples. In addition, we performed an immunohistochemistry analysis for ANPEP, which demonstrated overexpression of ANPEP in 6/7 (86%) Barrett's dysplasias and 35/65 (54%) BAs. ANPEP is a secreted protein that may have diagnostic and/or prognostic significance for Barrett's progression. The use of genomic approaches in this study provided useful information about the molecular pathobiology of BAs.
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Affiliation(s)
- Mohammad H. Razvi
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Dunfa Peng
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Altaf A. Dar
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Steven M. Powell
- Division of Gastroenterology, Vanderbilt University Medical Center, Nashville, TN
| | - Henry F. Frierson
- Department of Pathology, University of Virginia, Charlottesville, VA
| | | | - Kay Washington
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN
| | - Wael El‐Rifai
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN
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16
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Valerie K, Yacoub A, Hagan MP, Curiel DT, Fisher PB, Grant S, Dent P. Radiation-induced cell signaling: inside-out and outside-in. Mol Cancer Ther 2007; 6:789-801. [PMID: 17363476 DOI: 10.1158/1535-7163.mct-06-0596] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Exposure of tumor cells to clinically relevant doses of ionizing radiation causes DNA damage as well as mitochondria-dependent generation of reactive oxygen species. DNA damage causes activation of ataxia telangiectasia mutated and ataxia telangiectasia mutated and Rad3-related protein, which induce cell cycle checkpoints and also modulate the activation of prosurvival and proapoptotic signaling pathways, such as extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH(2)-terminal kinase 1/2, respectively. Radiation causes a rapid reactive oxygen species-dependent activation of ERBB family and other tyrosine kinases, leading to activation of RAS proteins and multiple protective downstream signaling pathways (e.g., AKT and ERK1/2), which alter transcription factor function and the apoptotic threshold of cells. The initial radiation-induced activation of ERK1/2 can promote the cleavage and release of paracrine ligands, which cause a temporally delayed reactivation of receptors and intracellular signaling pathways in irradiated and unirradiated bystander cells. Hence, signals from within the cell can promote activation of membrane-associated receptors, which signal back into the cytosol: signaling from inside the cell outward to receptors and then inward again via kinase pathways. However, cytosolic signaling can also cause release of membrane-associated paracrine factors, and thus, paracrine signals from outside of the cell can promote activation of growth factor receptors: signaling from the outside inward. The ultimate consequence of these signaling events after multiple exposures may be to reprogram the irradiated and affected bystander cells in terms of their expression levels of growth-regulatory and cell survival proteins, resulting in altered mitogenic rates and thresholds at which genotoxic stresses cause cell death. Inhibition of signaling in one and/or multiple survival pathways enhances radiosensitivity. Prolonged inhibition of any one of these pathways, however, gives rise to lineages of cells, which have become resistant to the inhibitor drug, by evolutionary selection for the clonal outgrowth of cells with point mutations in the specific targeted protein that make the target protein drug resistant or by the reprogramming of multiple signaling processes within all cells, to maintain viability. Thus, tumor cells are dynamic with respect to their reliance on specific cell signaling pathways to exist and rapidly adapt to repeated toxic challenges in an attempt to maintain tumor cell survival.
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Affiliation(s)
- Kristoffer Valerie
- Department of Biochemistry, Virginia Commonwealth University, 401 College Street, Box 980035, Richmond, VA 23298, USA
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17
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Lord CJ, Garrett MD, Ashworth A. Targeting the Double-Strand DNA Break Repair Pathway as a Therapeutic Strategy: Fig. 1. Clin Cancer Res 2006; 12:4463-8. [PMID: 16899589 DOI: 10.1158/1078-0432.ccr-06-1269] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DNA repair pathways are crucial for the maintenance of genome integrity. The pathway that repairs DNA double-strand breaks (DSB) has components involved in both signaling and repairing DNA damage. Impairing DSB repair using specific inhibitors of signaling or repair might, in principle, sensitize tumor cells to particular DNA-damaging agents. Moreover, the existence of specific defects in DNA repair pathways in tumors provides the rationale for the use of "synthetic lethal" approaches targeting this cellular "Achilles' heel." Here, we discuss the mechanisms involved in DSB repair and detail potential therapeutic approaches based on targeting this pathway.
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Affiliation(s)
- Christopher J Lord
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
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18
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Abstract
Loss of DNA mismatch repair (MMR) in mammalian cells, as well as having a causative role in cancer, has been linked to resistance to certain DNA damaging agents including clinically important cytotoxic chemotherapeutics. MMR-deficient cells exhibit defects in G2/M cell cycle arrest and cell killing when treated with these agents. MMR-dependent cell cycle arrest occurs, at least for low doses of alkylating agents, only after the second S-phase following DNA alkylation, suggesting that two rounds of DNA replication are required to generate a checkpoint signal. These results point to an indirect role for MMR proteins in damage signalling where aberrant processing of mismatches leads to the generation of DNA structures (single-strand gaps and/or double-strand breaks) that provoke checkpoint activation and cell killing. Significantly, recent studies have revealed that the role of MMR proteins in mismatch repair can be uncoupled from the MMR-dependent damage responses. Thus, there is a threshold of expression of MSH2 or MLH1 required for proper checkpoint and cell-death signalling, even though sub-threshold levels are sufficient for fully functional MMR repair activity. Segregation is also revealed through the identification of mutations in MLH1 or MSH2 that provide alleles functional in MMR but not in DNA damage responses and mutations in MSH6 that compromise MMR but not in apoptotic responses to DNA damaging agents. These studies suggest a direct role for MMR proteins in recognizing and signalling DNA damage responses that is independent of the MMR catalytic repair process. How MMR-dependent G2 arrest may link to cell death remains elusive and we speculate that it is perhaps the resolution of the MMR-dependent G2 cell cycle arrest following DNA damage that is important in terms of cell survival.
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Affiliation(s)
- Vincent O'Brien
- Centre for Oncology and Applied Pharmacology, Cancer Research UK Beatson Laboratories, Garscube Estate, Glasgow G61 1BD, UK.
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19
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Lu X, Nannenga B, Donehower LA. PPM1D dephosphorylates Chk1 and p53 and abrogates cell cycle checkpoints. Genes Dev 2005; 19:1162-74. [PMID: 15870257 PMCID: PMC1132003 DOI: 10.1101/gad.1291305] [Citation(s) in RCA: 302] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The ATM (ataxia-telangiectasia mutated) and ATR (ataxia-telangiectasia and Rad3-related) kinases respond to DNA damage by phosphorylating cellular target proteins that activate DNA repair pathways and cell cycle checkpoints in order to maintain genomic integrity. Here we show that the oncogenic p53-induced serine/threonine phosphatase, PPM1D (or Wip1), dephosphorylates two ATM/ATR targets, Chk1 and p53. PPM1D binds Chk1 and dephosphorylates the ATR-targeted phospho-Ser 345, leading to decreased Chk1 kinase activity. PPM1D also dephosphorylates p53 at phospho-Ser 15. PPM1D dephosphorylations are correlated with reduced cellular intra-S and G2/M checkpoint activity in response to DNA damage induced by ultraviolet and ionizing radiation. Thus, a primary function of PPM1D may be to reverse the p53 and Chk1-induced DNA damage and cell cycle checkpoint responses and return the cell to a homeostatic state following completion of DNA repair. These homeostatic functions may be partially responsible for the oncogenic effects of PPM1D when it is amplified and overexpressed in human tumors.
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Affiliation(s)
- Xiongbin Lu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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20
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Abstract
Protein serine/threonine phosphatases control key biological pathways including early embryonic development, cell proliferation, cell death, circadian rhythm and cancer. Recent studies have provided important insights into how several of the many phosphatase regulators, through their interaction with a conserved phosphatase catalytic subunit, control the activity of critical substrates in these diverse pathways. Recent co-crystal structures provided a major insight into how the diverse protein serine/threonine regulators rein in the otherwise promiscuous catalytic subunits.
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Affiliation(s)
- Monica Gallego
- Huntsman Cancer Institute, 2000 Circle of Hope, University of Utah, Salt Lake City, Utah 84112, USA
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21
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Goodarzi AA, Jonnalagadda JC, Douglas P, Young D, Ye R, Moorhead GBG, Lees-Miller SP, Khanna KK. Autophosphorylation of ataxia-telangiectasia mutated is regulated by protein phosphatase 2A. EMBO J 2004; 23:4451-61. [PMID: 15510216 PMCID: PMC526470 DOI: 10.1038/sj.emboj.7600455] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 10/01/2004] [Indexed: 11/09/2022] Open
Abstract
Ionizing radiation induces autophosphorylation of the ataxia-telangiectasia mutated (ATM) protein kinase on serine 1981; however, the precise mechanisms that regulate ATM activation are not fully understood. Here, we show that the protein phosphatase inhibitor okadaic acid (OA) induces autophosphorylation of ATM on serine 1981 in unirradiated cells at concentrations that inhibit protein phosphatase 2A-like activity in vitro. OA did not induce gamma-H2AX foci, suggesting that it induces ATM autophosphorylation by inactivation of a protein phosphatase rather than by inducing DNA double-strand breaks. In support of this, we show that ATM interacts with the scaffolding (A) subunit of protein phosphatase 2A (PP2A), that the scaffolding and catalytic (C) subunits of PP2A interact with ATM in undamaged cells and that immunoprecipitates of ATM from undamaged cells contain PP2A-like protein phosphatase activity. Moreover, we show that IR induces phosphorylation-dependent dissociation of PP2A from ATM and loss of the associated protein phosphatase activity. We propose that PP2A plays an important role in the regulation of ATM autophosphorylation and activity in vivo.
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Affiliation(s)
- Aaron A Goodarzi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, AB, Canada
| | | | - Pauline Douglas
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - David Young
- Queensland Institute of Medical Research, Brisbane, Australia
| | - Ruiqiong Ye
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Greg B G Moorhead
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Susan P Lees-Miller
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Kum Kum Khanna
- Queensland Institute of Medical Research, Brisbane, Australia
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