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Singh AK, Yadav D, Malviya R. Splicing DNA Damage Adaptations for the Management of Cancer Cells. Curr Gene Ther 2024; 24:135-146. [PMID: 38282448 DOI: 10.2174/0115665232258528231018113410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/07/2023] [Accepted: 09/25/2023] [Indexed: 01/30/2024]
Abstract
Maintaining a tumour cell's resistance to apoptosis (organized cell death) is essential for cancer to metastasize. Signal molecules play a critical function in the tightly regulated apoptotic process. Apoptosis may be triggered by a wide variety of cellular stresses, including DNA damage, but its ultimate goal is always the same: the removal of damaged cells that might otherwise develop into tumours. Many chemotherapy drugs rely on cancer cells being able to undergo apoptosis as a means of killing them. The mechanisms by which DNA-damaging agents trigger apoptosis, the interplay between pro- and apoptosis-inducing signals, and the potential for alteration of these pathways in cancer are the primary topics of this review.
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Affiliation(s)
- Arun Kumar Singh
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
| | - Deepika Yadav
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
| | - Rishabha Malviya
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
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2
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Kim DJ, Iwasaki A, Chien AL, Kang S. UVB-mediated DNA damage induces matrix metalloproteinases to promote photoaging in an AhR- and SP1-dependent manner. JCI Insight 2022; 7:156344. [PMID: 35316219 PMCID: PMC9090247 DOI: 10.1172/jci.insight.156344] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/18/2022] [Indexed: 11/17/2022] Open
Abstract
It is currently thought that UVB radiation drives photoaging of the skin primarily by generating ROS. In this model, ROS purportedly activates activator protein-1 to upregulate MMPs 1, 3, and 9, which then degrade collagen and other extracellular matrix components to produce wrinkles. However, these MMPs are expressed at relatively low levels and correlate poorly with wrinkles, suggesting that another mechanism distinct from ROS and MMP1/3/9 may be more directly associated with photoaging. Here we show that MMP2, which degrades type IV collagen, is abundantly expressed in human skin, increases with age in sun-exposed skin, and correlates robustly with aryl hydrocarbon receptor (AhR), a transcription factor directly activated by UV-generated photometabolites. Through mechanistic studies with HaCaT human immortalized keratinocytes, we found that AhR, specificity protein 1 (SP1), and other pathways associated with DNA damage are required for the induction of both MMP2 and MMP11 (another MMP implicated in photoaging), but not MMP1/3. Last, we found that topical treatment with AhR antagonists vitamin B12 and folic acid ameliorated UVB-induced wrinkle formation in mice while dampening MMP2 expression in the skin. These results directly implicate DNA damage in photoaging and reveal AhR as a potential target for preventing wrinkles.
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Affiliation(s)
- Daniel J Kim
- Department of Immunobiology, Yale University School of Medicine, New Haven, United States of America
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, United States of America
| | - Anna L Chien
- Department of Dermatology, Johns Hopkins School of Medicine, Baltimore, United States of America
| | - Sewon Kang
- Department of Dermatology, Johns Hopkins School of Medicine, Baltimore, United States of America
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3
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Fujita J, Taniguchi M, Hashizume C, Ueda Y, Sakai S, Kondo T, Hashimoto-Nishimura M, Hanada K, Kosaka T, Okazaki T. Nuclear Ceramide Is Associated with Ataxia Telangiectasia Mutated Activation in the Neocarzinostatin-Induced Apoptosis of Lymphoblastoid Cells. Mol Pharmacol 2022; 101:322-333. [PMID: 35273080 DOI: 10.1124/molpharm.121.000379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/22/2022] [Indexed: 01/14/2023] Open
Abstract
Ceramide is a bioactive sphingolipid that mediates ionizing radiation- and chemotherapy-induced apoptosis. Neocarzinostatin (NCS) is a genotoxic anti-cancer drug that induces apoptosis in response to DNA double-strand breaks (DSBs) through ataxia telangiectasia mutated (ATM) activation. However, the involvement of ceramide in NCS-evoked nuclear events such as DSB-activated ATM has not been clarified. Here, we found that nuclear ceramide increased by NCS-mediated apoptosis through the enhanced assembly of ATM and the meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 (MRN) complex proteins in human lymphoblastoid L-39 cells. NCS induced an increase of ceramide production through activation of neutral sphingomyelinase (nSMase) and suppression of sphingomyelin synthase (SMS) upstream of DSB-mediated ATM activation. In ATM-deficient lymphoblastoid AT-59 cells compared with L-39 cells, NCS treatment showed a decrease of apoptosis even though ceramide increase and DSBs were observed. Expression of wild-type ATM, but not the kinase-dead mutant ATM, in AT-59 cells increased NCS-induced apoptosis despite similar ceramide accumulation. Interestingly, NCS increased ceramide content in the nucleus through nSMase activation and SMS suppression and promoted colocalization of ceramide with phosphorylated ATM and foci of MRN complex. Inhibition of ceramide generation by the overexpression of SMS suppressed NCS-induced apoptosis through the inhibition of ATM activation and assembly of the MRN complex. In addition, inhibition of ceramide increased by the nSMase inhibitor GW4869 prevented NCS-mediated activation of the ATM. Therefore, our findings suggest the involvement of the nuclear ceramide with ATM activation in NCS-mediated apoptosis. SIGNIFICANCE STATEMENT: This study demonstrates that regulation of ceramide with neutral sphingomyelinase and sphingomyelin synthase in the nucleus in double-strand break-mimetic agent neocarzinostatin (NCS)-induced apoptosis. This study also showed that ceramide increase in the nucleus plays a role in NCS-induced apoptosis through activation of the ataxia telangiectasia mutated/meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 complex in human lymphoblastoid cells.
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Affiliation(s)
- Jun Fujita
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Makoto Taniguchi
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Chieko Hashizume
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Yoshibumi Ueda
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Shota Sakai
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Tadakazu Kondo
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Mayumi Hashimoto-Nishimura
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Kentaro Hanada
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Takeo Kosaka
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Toshiro Okazaki
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
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4
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Chen PH, Wu J, Ding CKC, Lin CC, Pan S, Bossa N, Xu Y, Yang WH, Mathey-Prevot B, Chi JT. Kinome screen of ferroptosis reveals a novel role of ATM in regulating iron metabolism. Cell Death Differ 2020; 27:1008-1022. [PMID: 31320750 PMCID: PMC7206124 DOI: 10.1038/s41418-019-0393-7] [Citation(s) in RCA: 160] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 06/22/2019] [Accepted: 07/01/2019] [Indexed: 01/18/2023] Open
Abstract
Ferroptosis is a specialized iron-dependent cell death that is associated with lethal lipid peroxidation. Modulation of ferroptosis may have therapeutic potential since it has been implicated in various human diseases as well as potential antitumor activities. However, much remains unknown about the underlying mechanisms and genetic determinants of ferroptosis. Given the critical role of kinases in most biological processes and the availability of various kinase inhibitors, we sought to systemically identify kinases essential for ferroptosis. We performed a forward genetic-based kinome screen against ferroptosis in MDA-MB-231 cells triggered by cystine deprivation. This screen identified 34 essential kinases involved in TNFα and NF-kB signaling. Unexpectedly, the DNA damage response serine/threonine kinase ATM (mutated in Ataxia-Telangiectasia) was found to be essential for ferroptosis. The pharmacological or genetic inhibition of ATM consistently rescued multiple cancer cells from ferroptosis triggered by cystine deprivation or erastin. Instead of the canonical DNA damage pathways, ATM inhibition rescued ferroptosis by increasing the expression of iron regulators involved in iron storage (ferritin heavy and light chain, FTH1 and FTL) and export (ferroportin, FPN1). The coordinated changes of these iron regulators during ATM inhibition resulted in a lowering of labile iron and prevented the iron-dependent ferroptosis. Furthermore, we found that ATM inhibition enhanced the nuclear translocation of metal-regulatory transcription factor 1 (MTF1), responsible for regulating expression of Ferritin/FPN1 and ferroptosis protection. Genetic depletion of MTF-1 abolished the regulation of iron-regulatory elements by ATM and resensitized the cells to ferroptosis. Together, we have identified an unexpected ATM-MTF1-Ferritin/FPN1 regulatory axis as novel determinants of ferroptosis through regulating labile iron levels.
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Affiliation(s)
- Po-Han Chen
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Jianli Wu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Chien-Kuang Cornelia Ding
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Chao-Chieh Lin
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Samuel Pan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Nathan Bossa
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, USA
| | - Yitong Xu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Wen-Hsuan Yang
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Bernard Mathey-Prevot
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Jen-Tsan Chi
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA. .,Duke Center for Genomic and Computational Biology, Duke University, Durham, NC, USA.
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5
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Goncalves MB, Moehlin J, Clarke E, Grist J, Hobbs C, Carr AM, Jack J, Mendoza-Parra MA, Corcoran JPT. RARβ Agonist Drug (C286) Demonstrates Efficacy in a Pre-clinical Neuropathic Pain Model Restoring Multiple Pathways via DNA Repair Mechanisms. iScience 2019; 20:554-566. [PMID: 31655065 PMCID: PMC6833472 DOI: 10.1016/j.isci.2019.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/06/2019] [Accepted: 09/12/2019] [Indexed: 01/05/2023] Open
Abstract
Neuropathic pain (NP) is associated with profound gene expression alterations within the nociceptive system. DNA mechanisms, such as epigenetic remodeling and repair pathways have been implicated in NP. Here we have used a rat model of peripheral nerve injury to study the effect of a recently developed RARβ agonist, C286, currently under clinical research, in NP. A 4-week treatment initiated 2 days after the injury normalized pain sensation. Genome-wide and pathway enrichment analysis showed that multiple mechanisms persistently altered in the spinal cord were restored to preinjury levels by the agonist. Concomitant upregulation of DNA repair proteins, ATM and BRCA1, the latter being required for C286-mediated pain modulation, suggests that early DNA repair may be important to prevent phenotypic epigenetic imprints in NP. Thus, C286 is a promising drug candidate for neuropathic pain and DNA repair mechanisms may be useful therapeutic targets to explore.
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Affiliation(s)
- Maria B Goncalves
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK.
| | - Julien Moehlin
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
| | - Earl Clarke
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - John Grist
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Carl Hobbs
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Julian Jack
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Marco Antonio Mendoza-Parra
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France.
| | - Jonathan P T Corcoran
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK.
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6
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Kamran MZ, Ranjan A, Kaur N, Sur S, Tandon V. Radioprotective Agents: Strategies and Translational Advances. Med Res Rev 2016; 36:461-93. [PMID: 26807693 DOI: 10.1002/med.21386] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/15/2015] [Accepted: 01/01/2016] [Indexed: 01/08/2023]
Abstract
Radioprotectors are agents required to protect biological system exposed to radiation, either naturally or through radiation leakage, and they protect normal cells from radiation injury in cancer patients undergoing radiotherapy. It is imperative to study radioprotectors and their mechanism of action comprehensively, looking at their potential therapeutic applications. This review intimately chronicles the rich intellectual, pharmacological story of natural and synthetic radioprotectors. A continuous effort is going on by researchers to develop clinically promising radioprotective agents. In this article, for the first time we have discussed the impact of radioprotectors on different signaling pathways in cells, which will create a basis for scientific community working in this area to develop novel molecules with better therapeutic efficacy. The bright future of exceptionally noncytotoxic derivatives of bisbenzimidazoles is also described as radiomodulators. Amifostine, an effective radioprotectant, has been approved by the FDA for limited clinical use. However, due to its adverse side effects, it is not routinely used clinically. Recently, CBLB502 and several analog of a peptide are under clinical trial and showed high success against radiotherapy in cancer. This article reviews the different types of radioprotective agents with emphasis on the strategies for the development of novel radioprotectors for drug development. In addition, direction for future strategies relevant to the development of radioprotectors is also addressed.
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Affiliation(s)
- Mohammad Zahid Kamran
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Atul Ranjan
- Kansas University of Medical Center, Kansas City, KS, 66160
| | - Navrinder Kaur
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, 110007, India
| | - Souvik Sur
- Department of Chemistry, University of Delhi, Delhi, 110007, India
| | - Vibha Tandon
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.,Department of Chemistry, University of Delhi, Delhi, 110007, India
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7
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Sinha S, Ghildiyal R, Mehta VS, Sen E. ATM-NFκB axis-driven TIGAR regulates sensitivity of glioma cells to radiomimetics in the presence of TNFα. Cell Death Dis 2013; 4:e615. [PMID: 23640457 PMCID: PMC3674344 DOI: 10.1038/cddis.2013.128] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Gliomas are resistant to radiation therapy, as well as to TNFα induced killing. Radiation-induced TNFα triggers Nuclear factor κB (NFκB)-mediated radioresistance. As inhibition of NFκB activation sensitizes glioma cells to TNFα-induced apoptosis, we investigated whether TNFα modulates the responsiveness of glioma cells to ionizing radiation-mimetic Neocarzinostatin (NCS). TNFα enhanced the ability of NCS to induce glioma cell apoptosis. NCS-mediated death involved caspase-9 activation, reduction of mitochondrial copy number and lactate production. Death was concurrent with NFκB, Akt and Erk activation. Abrogation of Akt and NFκB activation further potentiated the death inducing ability of NCS in TNFα cotreated cells. NCS-induced p53 expression was accompanied by increase in TP53-induced glycolysis and apoptosis regulator (TIGAR) levels and ATM phosphorylation. siRNA-mediated knockdown of TIGAR abrogated NCS-induced apoptosis. While DN-IκB abrogated NCS-induced TIGAR both in the presence and absence of TNFα, TIGAR had no effect on NFκB activation. Transfection with TIGAR mutant (i) decreased apoptosis and γH2AX foci formation (ii) decreased p53 (iii) elevated ROS and (iv) increased Akt/Erk activation in cells cotreated with NCS and TNFα. Heightened TIGAR expression was observed in GBM tumors. While NCS induced ATM phosphorylation in a NFκB independent manner, ATM inhibition abrogated TIGAR and NFκB activation. Metabolic gene profiling indicated that TNFα affects NCS-mediated regulation of several genes associated with glycolysis. The existence of ATM-NFκB axis that regulate metabolic modeler TIGAR to overcome prosurvival response in NCS and TNFα cotreated cells, suggests mechanisms through which inflammation could affect resistance and adaptation to radiomimetics despite concurrent induction of death.
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Affiliation(s)
- S Sinha
- Cellular and Molecular Neuroscience Division, National Brain Research Centre, Manesar, Haryana, India
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8
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Abstract
Long interspersed element-1 (LINE-1 or L1) is a repetitive DNA retrotransposon capable of duplication by a copy-and-paste genetic mechanism. Scattered throughout mammalian genomes, L1 is typically quiescent in most somatic cell types. In developing neurons, however, L1 can express and retrotranspose at high frequency. The L1 element can insert into various genomic locations including intragenic regions. These insertions can alter the dynamic of the neuronal transcriptome by changing the expression pattern of several nearby genes. The consequences of L1 genomic alterations in somatic cells are still under investigation, but the high level of mutagenesis within neurons suggests that each neuron is genetically unique. Furthermore, some neurological diseases, such as Rett syndrome and ataxia telangiectasia, misregulate L1 retrotransposition, which could contribute to some pathological aspects. In this review, we survey the literature related to neurodevelopmental retrotransposition and discuss possible relevance to neuronal function, evolution, and neurological disease.
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Affiliation(s)
- Charles A Thomas
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California 92093, USA
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9
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ATM kinase activity modulates ITCH E3-ubiquitin ligase activity. Oncogene 2013; 33:1113-23. [PMID: 23435430 PMCID: PMC3938399 DOI: 10.1038/onc.2013.52] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 12/27/2022]
Abstract
Ataxia Telangiectasia Mutated (ATM) kinase, a central regulator of the DNA damage response regulates the activity of several E3-ubiquitin ligases and the ubiquitination-proteasome system is a consistent target of ATM. ITCH is an E3-ubiquitin ligase that modulates the ubiquitination of several targets, therefore participating to the regulation of several cellular responses, among which the DNA damage response, TNFα, Notch and Hedgehog signalling and T cell development. Here we uncover ATM as a novel positive modulator of ITCH E3-ubiquitin ligase activity. A single residue on ITCH protein, S161, which is part of an ATM SQ consensus motif, is required for ATM-dependent activation of ITCH. ATM activity enhances ITCH enzymatic activity, which in turn drives the ubiquitination and degradation of c-FLIP-L and c-Jun, previously identified as ITCH substrates. Importantly, Atm deficient mice show resistance to hepatocyte cell death, similarly to Itch deficient animals, providing in vivo genetic evidence for this circuit. Our data identify ITCH as a novel component of the ATM-dependent signaling pathway and suggest that the impairment of the correct functionality of ITCH caused by Atm deficiency may contribute to the complex clinical features linked to Ataxia Telangiectasia.
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10
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Role for Prdx1 as a specific sensor in redox-regulated senescence in breast cancer. Oncogene 2013; 32:5302-14. [PMID: 23334324 DOI: 10.1038/onc.2012.624] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 11/21/2012] [Accepted: 11/30/2012] [Indexed: 02/07/2023]
Abstract
Recent studies suggest that Peroxiredoxin 1 (Prdx1), in addition to its known H₂O₂-scavenging function, mediates cell signaling through redox-specific protein-protein interactions. Our data illustrate how Prdx1 specifically coordinates p38MAPK-induced signaling through regulating p38MAPKα phosphatases in an H₂O₂ dose-dependent manner. MAPK phosphatases (MKP-1 and/or MKP-5), which are known to dephosphorylate and deactivate the senescence-inducing MAPK p38α, belong to a group of redox-sensitive phosphatases (protein tyrosine phosphatases) characterized by a low pKa cysteine in their active sites. We found that Prdx1 bound to both MKP-1 and MKP-5, but dissociated from MKP-1 when the Prdx1 peroxidatic cysteine Cys52 was over-oxidized to sulfonic acid, which in turn resulted in MKP-1 oxidation-induced oligomerization and inactivity toward p38MAPKα. Conversely, over-oxidation of Prdx1-Cys52 was enhancing in the Prdx1:MKP-5 complex with increasing amounts of H₂O₂ concentrations and correlated with a protection from oxidation-induced oligomerization and inactivation of MKP-5 so that activation toward p38MAPK was maintained. Further examination of this Prdx1-specific mechanism in a model of reactive oxygen species-induced senescence of human breast epithelial cells revealed the specific activation of MKP-5, resulting in decreased p38MAPKα activity. Taken together, our data suggest that Prdx1 orchestrates redox signaling in an H₂O₂ dose-dependent manner through the oxidation status of its peroxidatic cysteine Cys52.
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11
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Kondoh K, Nishida E. Regulation of MAP kinases by MAP kinase phosphatases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1227-37. [PMID: 17208316 DOI: 10.1016/j.bbamcr.2006.12.002] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/05/2006] [Accepted: 12/06/2006] [Indexed: 11/24/2022]
Abstract
MAP kinase phosphatases (MKPs) catalyze dephosphorylation of activated MAP kinase (MAPK) molecules and deactivate them. Therefore, MKPs play an important role in determining the magnitude and duration of MAPK activities. MKPs constitute a structurally distinct family of dual-specificity phosphatases. The MKP family members share the sequence homology and the preference for MAPK molecules, but they are different in substrate specificity among MAPK molecules, tissue distribution, subcellular localization and inducibility by extracellular stimuli. Our understanding of their protein structure, substrate recognition mechanisms, and regulatory mechanisms of the enzymatic activity has greatly increased over the past few years. Furthermore, although there are a number of MKPs, that have similar substrate specificities, non-redundant roles of MKPs have begun to be identified. Here we focus on recent findings regarding regulation and function of the MKP family members as physiological regulators of MAPK signaling.
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Affiliation(s)
- Kunio Kondoh
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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12
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Nyati MK, Feng FY, Maheshwari D, Varambally S, Zielske SP, Ahsan A, Chun PY, Arora VA, Davis MA, Jung M, Ljungman M, Canman CE, Chinnaiyan AM, Lawrence TS. Ataxia Telangiectasia Mutated Down-regulates Phospho-Extracellular Signal-Regulated Kinase 1/2 via Activation of MKP-1 in Response to Radiation. Cancer Res 2006; 66:11554-9. [PMID: 17178844 DOI: 10.1158/0008-5472.can-06-1935] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ataxia telangiectasia mutated (ATM) kinase plays a crucial role in the cellular response to DNA damage and in radiation resistance. Although much effort has focused on the relationship between ATM and other nuclear signal transducers, little is known about interactions between ATM and mitogenic signaling pathways. In this study, we show a novel relationship between ATM kinase and extracellular signal-regulated kinase 1/2 (ERK1/2), a key mitogenic stimulator. Activation of ATM by radiation down-regulates phospho-ERK1/2 and its downstream signaling via increased expression of mitogen-activated protein kinase phosphatase MKP-1 in both cell culture and tumor models. This dephosphorylation of ERK1/2 is independent of epidermal growth factor receptor (EGFR) activity and is associated with radioresistance. These findings show a new function for ATM in the control of mitogenic pathways affecting cell signaling and emphasize the key role of ATM in coordinating the cellular response to DNA damage.
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MESH Headings
- Animals
- Antigens, Differentiation/genetics
- Ataxia Telangiectasia Mutated Proteins
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/pathology
- Carcinoma, Squamous Cell/radiotherapy
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Cycle Proteins/radiation effects
- Cell Line, Tumor
- Cell Survival
- DNA Damage
- DNA Replication
- DNA-Binding Proteins/genetics
- Dual Specificity Phosphatase 1
- Enzyme Activation
- Gene Expression Regulation, Neoplastic
- Humans
- Immediate-Early Proteins/metabolism
- Immediate-Early Proteins/radiation effects
- Membrane Glycoproteins/genetics
- Mice
- Mice, Nude
- Neural Cell Adhesion Molecules/genetics
- Phosphoprotein Phosphatases/metabolism
- Phosphoprotein Phosphatases/radiation effects
- Polymerase Chain Reaction
- Protein Phosphatase 1
- Protein Serine-Threonine Kinases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Protein Tyrosine Phosphatases/radiation effects
- RNA, Neoplasm/genetics
- RNA, Neoplasm/isolation & purification
- Receptors, Immunologic/genetics
- Transplantation, Heterologous
- Tumor Suppressor Proteins/genetics
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Affiliation(s)
- Mukesh K Nyati
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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13
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Lin Y, Yang Q, Wang X, Liu ZG. The Essential Role of the Death Domain Kinase Receptor-interacting Protein in Insulin Growth Factor-I-induced c-Jun N-terminal Kinase Activation. J Biol Chem 2006; 281:23525-32. [PMID: 16793775 DOI: 10.1074/jbc.m601487200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Insulin-like growth factor I (IGF-I) plays an important role in cell survival, proliferation, and differentiation. Diverse kinases, including AKT/protein kinase B, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), can be activated by IGF-I. Here, we show that the receptor-interacting protein (RIP), a key mediator of tumor necrosis factor-induced NF-kappaB and JNK activation, plays a key role in IGF-I receptor signaling. IGF-I induced a robust JNK activation in wild type but not RIP null (RIP-/-) mouse embryonic fibroblast cells. Reconstitution of RIP expression in the RIP-/- cells restored the induction of JNK by IGF-I, suggesting that RIP is essential in IGF-I-induced JNK activation. Reconstitution experiments with different RIP mutants further revealed that the death domain and the kinase activity of RIP are not required for IGF-I-induced JNK activation. Interestingly, the AKT and ERK activation by IGF-I was normal in RIP-/- cells. The phosphatidylinositol 3-kinase inhibitor, wortmannin, did not affect IGF-I-induced JNK activation. These results agree with previous studies showing that the IGF-I-induced JNK activation pathway is distinct from that of ERK and AKT activation. Additionally, physical interaction of ectopically expressed RIP and IGF-IRbeta was detected by co-immunoprecipitation assays. More importantly, RIP was recruited to the IGF-I receptor complex during IGF-I-induced signaling. Furthermore, we found that IGF-I-induced cell proliferation was impaired in RIP-/- cells. Taken together, our results indicate that RIP, a key factor in tumor necrosis factor signaling, also plays a pivotal role in IGF-I-induced JNK activation and cell proliferation.
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Affiliation(s)
- Yong Lin
- Molecular Biology and Lung Cancer Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108, USA.
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14
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Abstract
The ability of a tumour cell to evade programmed cell death (apoptosis) is crucial in the development of cancer. The process of apoptosis is complex and involves the careful interplay of a host of signalling molecules. Cellular stresses, such as DNA-damage, can initiate apoptosis through multiple pathways, all of which eventually lead to eradication of damaged cells that may otherwise go on to form a tumour. Moreover, the relevance of this to combating cancer is very strong since several therapeutic agents used to treat malignant disease utilize the cells' apoptotic machinery. The purpose of this review is to provide an insight into what we know about how apoptosis is initiated by DNA-damaging agents, how pro- and anti-apoptotic signals converge in the execution of cell death, and how such mechanisms can be perturbed in cancer.
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Affiliation(s)
- Diane Crighton
- Tumour Cell Death Laboratory, Beatson Institute for Cancer Research, Cancer Research UK Beatson Laboratories, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
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15
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Heinzelmann-Schwarz V, Fedier A, Hornung R, Walt H, Haller U, Fink D. Role of p53 and ATM in photodynamic therapy-induced apoptosis. Lasers Surg Med 2004; 33:182-9. [PMID: 12949948 DOI: 10.1002/lsm.10213] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES Photodynamic therapy (PDT) induces cell death through a laser light-activated photosensitizer and is a treatment option for tumors resistant to radio- and chemo-therapy. STUDY DESIGN/MATERIALS AND METHODS We investigated whether m-THPC-PDT induces cell death by necrosis and/or apoptosis, and whether these responses are modulated by p53 and/or ATM, two cancer-associated genes. Sensitivity of atm(+/+)p53(+/+), atm(+/+)p53(-/-), and atm(-/-)p53(-/-) mouse embryonic fibroblasts to m-THPC-PDT performed at a wavelength of 652 nm was determined by the MTT assay, trypan blue-exclusion, and the TUNEL and caspase3-cleavage apoptosis assays. c-Abl protein level was determined by immunoblotting. RESULTS m-THPC-PDT rapidly induced cell death in a substantial fraction of cells by p53- and Ataxia telangiectasia mutated (ATM)-independent non-apoptotic processes. However, in the subset of apoptotic cells, apoptosis was reduced by loss of p53 and was even more reduced by the additional loss of ATM. Apoptosis correlated inversely with c-Abl level. CONCLUSIONS p53 and ATM are not required for necrosis, but may be required for PDT-mediated apoptosis.
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Affiliation(s)
- Viola Heinzelmann-Schwarz
- Department of Obstetrics and Gynecology, Division of Gynecology, University Hospital of Zurich, 8091 Zurich, Switzerland
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16
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Abstract
Cellular response to genotoxic stress is a very complex process, and it usually starts with the “sensing” or “detection” of the DNA damage, followed by a series of events that include signal transduction and activation of transcription factors. The activated transcription factors induce expressions of many genes which are involved in cellular functions such as DNA repair, cell cycle arrest, and cell death. There have been extensive studies from multiple disciplines exploring the mechanisms of cellular genotoxic responses, which have resulted in the identification of many cellular components involved in this process, including the mitogen-activated protein kinases (MAPKs) cascade. Although the initial activation of protein kinase cascade is not fully understood, human protein kinases ATM (ataxia-telangiectasia, mutated) and ATR (ATM and Rad3-related) are emerging as potential sensors of DNA damage. Current progresses in ATM/ATR research and related signaling pathways are discussed in this review, in an effort to facilitate a better understanding of genotoxic stress response.
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Affiliation(s)
- Jun Yang
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, 353 Yanan Road, Hangzhou, 310031, Zhejiang Province, China
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17
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Abstract
Ataxia telangiectasia is one of a group of recessive hereditary genomic instability disorders and is characterized by progressive neurodegeneration, immunodeficiency and cancer susceptibility. Heterozygotes for the mutated gene are more susceptible to cancer and to ischaemic heart disease. The affected gene, ATM (ataxia telangiectasia mutated), has been cloned and codes for a protein kinase (ATM), which orchestrates the cellular response to DNA double-strand breaks after ionising radiation. An underlying feature of ataxia telangiectasia is oxidative stress and there is chronic activation of stress response pathways in tissues showing pathology such as the cerebellum, but not in the cerebrum or liver. ATM has also been shown to be activated by insulin and to have a wider role in signal transduction and cell growth. Many, but not all, aspects of the phenotype can be attributed to a defective DNA damage response. The oxidative stress may result directly from accumulated DNA damage in affected tissues or ATM may have an additional role in sensing/modulating redox homeostasis. The basis for the observed tissue specificity of the oxidative damage in ataxia telangiectasia is not clear.
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Affiliation(s)
- Dianne J Watters
- School of Biomolecular and Biomedical Science, Griffith University, Brisbane, Queensland, Australia.
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18
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Abstract
The double-strand break (DSB) is believed to be one of the most severe types of DNA damage, and if left unrepaired is lethal to the cell. Several different types of repair act on the DSB. The most important in mammalian cells are nonhomologous end-joining (NHEJ) and homologous recombination repair (HRR). NHEJ is the predominant type of DSB repair in mammalian cells, as opposed to lower eucaryotes, but HRR has recently been implicated in critical cell signaling and regulatory functions that are essential for cell viability. Whereas NHEJ repair appears constitutive, HRR is regulated by the cell cycle and inducible signal transduction pathways. More is known about the molecular details of NHEJ than HRR in mammalian cells. This review focuses on the mechanisms and regulation of DSB repair in mammalian cells, the signaling pathways that regulate these processes and the potential crosstalk between NHEJ and HRR, and between repair and other stress-induced pathways with emphasis on the regulatory circuitry associated with the ataxia telangiectasia mutated (ATM) protein.
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Affiliation(s)
- Kristoffer Valerie
- Department of Radiation Oncology, Medical College of Virginia Commonwealth University, Richmond, VA 23298-0058, USA.
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19
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Abstract
Within the last 15 years, multiple new signal transduction pathways within cells have been discovered. Many of these pathways belong to what is now termed 'the mitogen-activated protein kinase (MAPK) superfamily.' These pathways have been linked to the growth factor-mediated regulation of diverse cellular events such as proliferation, senescence, differentiation and apoptosis. Based on currently available data, exposure of cells to ionizing radiation and a variety of other toxic stresses induces simultaneous compensatory activation of multiple MAPK pathways. These signals play critical roles in controlling cell survival and repopulation effects following irradiation, in a cell-type-dependent manner. Some of the signaling pathways activated following radiation exposure are those normally activated by mitogens, such as the 'classical' MAPK (also known as the ERK) pathway. Other MAPK pathways activated by radiation include those downstream of death receptors and procaspases, and DNA-damage signals, including the JNK and P38 MAPK pathways. The expression and release of autocrine growth factor ligands, such as (transforming growth factor alpha) and TNF-alpha, following irradiation can also enhance the responses of MAPK pathways in cells and, consequently, of bystander cells. Thus, the ability of radiation to activate MAPK signaling pathways may depend on the expression of multiple growth factor receptors, autocrine factors and Ras mutation. Enhanced basal signaling by proto-oncogenes such as K-/H-/N-RAS may provide a radioprotective and growth-promoting signal. In many cell types, this may be via the PI3K pathway; in others, this may occur through nuclear factor-kappa B or multiple MAPK pathways. This review will describe the enzymes within the known MAPK signaling pathways and discuss their activation and roles in cellular radiation responses.
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Affiliation(s)
- Paul Dent
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298-0058, USA.
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20
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Kool J, Hamdi M, Cornelissen-Steijger P, van der Eb AJ, Terleth C, van Dam H. Induction of ATF3 by ionizing radiation is mediated via a signaling pathway that includes ATM, Nibrin1, stress-induced MAPkinases and ATF-2. Oncogene 2003; 22:4235-42. [PMID: 12833146 DOI: 10.1038/sj.onc.1206611] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Exposure of human cells to genotoxic agents induces various signaling pathways involved in the execution of stress- and DNA-damage responses. Inappropriate functioning of the DNA-damage response to ionizing radiation (IR) is associated with the human diseases ataxia-telangiectasia (A-T) and Nijmegen Breakage syndrome (NBS). Here, we show that IR efficiently induces Jun/ATF transcription factor activity in normal human diploid fibroblasts, but not in fibroblasts derived from A-T and NBS patients. IR was found to enhance the expression of c-Jun and, in particular, ATF3, but, in contrast to various other stress stimuli, did not induce the expression of c-Fos. Using specific inhibitors, we found that the ATM- and Nibrin1-dependent activation of ATF3 does neither require p53 nor reactive oxygen species, but is dependent on the p38 and JNK MAPkinases. Via these kinases, IR activates ATF-2, one of the transcription factors acting on the atf3 promoter. The activation of ATF-2 by IR resembles ATF-2 activation by certain growth factors, since IR mainly induced the second step of ATF-2 phosphorylation via the stress-inducible MAPkinases, phosphorylation of Thr69. As IR does not enhance ATF-2 phosphorylation in ATM and Nibrin1-deficient cells, both ATF-2 and ATF3 seem to play an important role in the protective response of human cells to IR.
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Affiliation(s)
- Jaap Kool
- Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Centre, Wassenaarseweg 72, 2333AL Leiden, The Netherlands
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21
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Abstract
Maintenance of genome stability is essential for avoiding the passage to neoplasia. The DNA-damage response--a cornerstone of genome stability--occurs by a swift transduction of the DNA-damage signal to many cellular pathways. A prime example is the cellular response to DNA double-strand breaks, which activate the ATM protein kinase that, in turn, modulates numerous signalling pathways. ATM mutations lead to the cancer-predisposing genetic disorder ataxia-telangiectasia (A-T). Understanding ATM's mode of action provides new insights into the association between defective responses to DNA damage and cancer, and brings us closer to resolving the issue of cancer predisposition in some A-T carriers.
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Affiliation(s)
- Yosef Shiloh
- The David and Inez Myers Laboratory for Genetic Research, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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22
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Weizman N, Shiloh Y, Barzilai A. Contribution of the Atm protein to maintaining cellular homeostasis evidenced by continuous activation of the AP-1 pathway in Atm-deficient brains. J Biol Chem 2003; 278:6741-7. [PMID: 12496286 DOI: 10.1074/jbc.m211168200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Maintenance of genome stability is essential for keeping cellular homeostasis. The DNA damage response is a central component in maintaining genome integrity. Among of the most cytotoxic DNA lesions are double strand breaks (DSBs) caused by ionizing radiation or radiomimetic chemicals. ATM is missing or inactivated in patients with ataxia-telangiectasia. Ataxia-telangiectasia patients display a pleiotropic phenotype and suffer primarily from progressive ataxia caused by degeneration of cerebellar Purkinje and granule neurons. Additional features are immunodeficiency, genomic instability, radiation sensitivity, and cancer predisposition. Disruption of the mouse Atm locus creates a murine model of ataxia-telangiectasia that exhibits most of the clinical features of the human disease but very mild neuronal abnormality. The ATM protein is a multifunctional protein kinase, which serves as a master regulator of cellular responses to DSBs. There is growing evidence that ATM may be involved in addition to the DSB response in other processes that maintain processes in cellular homeostasis. For example, mounting evidence points to increased oxidative stress in the absence of ATM. Here we report that the AP-1 pathway is constantly active in the brains of Atm-deficient mice not treated with DNA damaging agents. A canonical activation (increased phosphorylation of mitogen-activated protein kinase kinase-4, c-Jun N-terminal kinase, and c-Jun) of the AP-1 pathway was found in Atm-deficient cerebra, whereas induction of the AP-1 pathway in Atm-deficient cerebella is likely to mediate elevated expression of c-Fos and c-Jun. Although Atm(+/+) mice are capable of responding to ionizing radiation by activating stress responses such as the AP-1 pathway, Atm-deficient mice display higher basal AP-1 activity but gradually lose their ability to activate AP-1 DNA-binding activity in response to ionizing radiation. Our results further demonstrate that inactivation of the ATM gene results in a state of constant stress.
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Affiliation(s)
- Nir Weizman
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 Israel
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23
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Abstract
We review the genes and proteins related to the homologous recombinational repair (HRR) pathway that are implicated in cancer through either genetic disorders that predispose to cancer through chromosome instability or the occurrence of somatic mutations that contribute to carcinogenesis. Ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), and an ataxia-like disorder (ATLD), are chromosome instability disorders that are defective in the ataxia telangiectasia mutated (ATM), NBS, and Mre11 genes, respectively. These genes are critical in maintaining cellular resistance to ionizing radiation (IR), which kills largely by the production of double-strand breaks (DSBs). Bloom syndrome involves a defect in the BLM helicase, which seems to play a role in restarting DNA replication forks that are blocked at lesions, thereby promoting chromosome stability. The Werner syndrome gene (WRN) helicase, another member of the RecQ family like BLM, has very recently been found to help mediate homologous recombination. Fanconi anemia (FA) is a genetically complex chromosomal instability disorder involving seven or more genes, one of which is BRCA2. FA may be at least partially caused by the aberrant production of reactive oxidative species. The breast cancer-associated BRCA1 and BRCA2 proteins are strongly implicated in HRR; BRCA2 associates with Rad51 and appears to regulate its activity. We discuss in detail the phenotypes of the various mutant cell lines and the signaling pathways mediated by the ATM kinase. ATM's phosphorylation targets can be grouped into oxidative stress-mediated transcriptional changes, cell cycle checkpoints, and recombinational repair. We present the DNA damage response pathways by using the DSB as the prototype lesion, whose incorrect repair can initiate and augment karyotypic abnormalities.
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Affiliation(s)
- Larry H Thompson
- Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory L-441, P.O. Box 808, Livermore, CA 94551-0808, USA.
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24
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Pamment J, Ramsay E, Kelleher M, Dornan D, Ball KL. Regulation of the IRF-1 tumour modifier during the response to genotoxic stress involves an ATM-dependent signalling pathway. Oncogene 2002; 21:7776-85. [PMID: 12420214 DOI: 10.1038/sj.onc.1205981] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2002] [Revised: 08/16/2002] [Accepted: 08/16/2002] [Indexed: 11/08/2022]
Abstract
The mechanism by which genotoxic stress induces IRF-1 and the signalling components upstream of this anti-oncogenic transcription factor during the response to DNA damage are not known. We demonstrate that IRF-1 and the tumour suppressor protein p53 are coordinately up-regulated during the response to DNA damage in an ATM-dependent manner. Induction of IRF-1 protein by either ionizing radiation (IR) or etoposide occurs through a concerted mechanism involving increased IRF-1 expression/synthesis and an increase in the half-life of the IRF-1 protein. A striking defect in the induction of both IRF-1 mRNA and IRF-1 protein was observed in ATM deficient cells. Although ATM deficient cells failed to increase IRF-1 in response to genotoxic stress, the induction of IRF-1 in response to viral mimetics remained intact. Re-expression of the ATM kinase in AT cells restored the DNA damage inducibility of IRF-1, whilst the PI-3 kinase inhibitor wortmannin inhibited IRF-1 induction by DNA damage in ATM-positive cells. The data highlight a role for the ATM kinase in orchestrating the coordinated induction and transcriptional cooperation of IRF-1 and p53 to regulate p21 expression. Thus, IRF-1 is controlled by two distinct signalling pathways; a JAK/STAT-signalling pathway in viral infected cells and an ATM-signalling pathway in DNA damaged cells.
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Affiliation(s)
- Jessica Pamment
- Cancer Research UK Laboratories, University of Dundee Medical School, Dundee DD1 9SY, UK
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25
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Sun X, Becker-Catania SG, Chun HH, Hwang MJ, Huo Y, Wang Z, Mitui M, Sanal O, Chessa L, Crandall B, Gatti RA. Early diagnosis of ataxia-telangiectasia using radiosensitivity testing. J Pediatr 2002; 140:724-31. [PMID: 12072877 DOI: 10.1067/mpd.2002.123879] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES To utilize radiosensitivity testing to improve early diagnosis of patients with ataxia-telangiectasia (A-T). STUDY DESIGN We established normal ranges for the colony survival assay (CSA) by testing cells from 104 patients with typical A-T, 29 phenotypic normal patients, and 19 A-T heterozygotes. We also analyzed 61 samples from patients suspected of having A-T and 25 patients with related disorders to compare the CSA with other criteria in the diagnosis of A-T. RESULTS When cells were irradiated with 1.0 Gy, the mean survival fraction (microSF +/- 1 SD) for patients with A-T was 13.1% +/- 7.2% compared with 50.1% +/- 13.5% for healthy control patients. These data served to define a diagnostic range for the CSA (ie, <21%), a normal range (>36%), and a nondiagnostic intermediate range of 21% to 36%. The mutations of patients with A-T with intermediate radiosensitivity tended to cluster around the functional domains of the ATM gene. CONCLUSIONS The CSA is a useful adjunctive test for confirming an early clinical diagnosis of A-T. However, CSA is also abnormal in other chromosomal instability and immunodeficiency disorders.
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Affiliation(s)
- Xia Sun
- Department of Pathology, UCLA School of Medicine, Los Angeles, California 90095-1732, USA
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