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Xiao H, Li F, Mladenov E, Soni A, Mladenova V, Pan B, Dueva R, Stuschke M, Timmermann B, Iliakis G. Increased Resection at DSBs in G2-Phase Is a Unique Phenotype Associated with DNA-PKcs Defects That Is Not Shared by Other Factors of c-NHEJ. Cells 2022; 11:cells11132099. [PMID: 35805183 PMCID: PMC9265841 DOI: 10.3390/cells11132099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 01/27/2023] Open
Abstract
The load of DNA double-strand breaks (DSBs) induced in the genome of higher eukaryotes by different doses of ionizing radiation (IR) is a key determinant of DSB repair pathway choice, with homologous recombination (HR) and ATR substantially gaining ground at doses below 0.5 Gy. Increased resection and HR engagement with decreasing DSB-load generate a conundrum in a classical non-homologous end-joining (c-NHEJ)-dominated cell and suggest a mechanism adaptively facilitating resection. We report that ablation of DNA-PKcs causes hyper-resection, implicating DNA-PK in the underpinning mechanism. However, hyper-resection in DNA-PKcs-deficient cells can also be an indirect consequence of their c-NHEJ defect. Here, we report that all tested DNA-PKcs mutants show hyper-resection, while mutants with defects in all other factors of c-NHEJ fail to do so. This result rules out the model of c-NHEJ versus HR competition and the passive shift from c-NHEJ to HR as the causes of the increased resection and suggests the integration of DNA-PKcs into resection regulation. We develop a model, compatible with the results of others, which integrates DNA-PKcs into resection regulation and HR for a subset of DSBs. For these DSBs, we propose that the kinase remains at the break site, rather than the commonly assumed autophosphorylation-mediated removal from DNA ends.
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Affiliation(s)
- Huaping Xiao
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Fanghua Li
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Department of Particle Therapy, University Hospital Essen, West German Proton Therapy Centre Essen (WPE), West German Cancer Center (WTZ), German Cancer Consortium (DKTK), 45147 Essen, Germany;
| | - Emil Mladenov
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Aashish Soni
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Veronika Mladenova
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Bing Pan
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Rositsa Dueva
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany
| | - Martin Stuschke
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, German Cancer Research Center (DKFZ), 45147 Essen, Germany
| | - Beate Timmermann
- Department of Particle Therapy, University Hospital Essen, West German Proton Therapy Centre Essen (WPE), West German Cancer Center (WTZ), German Cancer Consortium (DKTK), 45147 Essen, Germany;
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, German Cancer Research Center (DKFZ), 45147 Essen, Germany
| | - George Iliakis
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany; (H.X.); (F.L.); (E.M.); (A.S.); (V.M.); (B.P.); (R.D.)
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
- Correspondence: ; Tel.: +49-201-723-4152
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Dylgjeri E, Knudsen KE. DNA-PKcs: A Targetable Protumorigenic Protein Kinase. Cancer Res 2022; 82:523-533. [PMID: 34893509 PMCID: PMC9306356 DOI: 10.1158/0008-5472.can-21-1756] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/17/2021] [Accepted: 11/10/2021] [Indexed: 01/07/2023]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a pleiotropic protein kinase that plays critical roles in cellular processes fundamental to cancer. DNA-PKcs expression and activity are frequently deregulated in multiple hematologic and solid tumors and have been tightly linked to poor outcome. Given the potentially influential role of DNA-PKcs in cancer development and progression, therapeutic targeting of this kinase is being tested in preclinical and clinical settings. This review summarizes the latest advances in the field, providing a comprehensive discussion of DNA-PKcs functions in cancer and an update on the clinical assessment of DNA-PK inhibitors in cancer therapy.
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Affiliation(s)
- Emanuela Dylgjeri
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Karen E. Knudsen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Medical Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Corresponding Author: Karen E. Knudsen, Thomas Jefferson University, 233 South 10th Street, BLSB 1050, Philadelphia, PA 19107. Phone: 215-503-5692; E-mail:
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Panigrahi R, Glover JNM. Structural insights into DNA double-strand break signaling. Biochem J 2021; 478:135-156. [PMID: 33439989 DOI: 10.1042/bcj20200066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022]
Abstract
Genomic integrity is most threatened by double-strand breaks, which, if left unrepaired, lead to carcinogenesis or cell death. The cell generates a network of protein-protein signaling interactions that emanate from the DNA damage which are now recognized as a rich basis for anti-cancer therapy development. Deciphering the structures of signaling proteins has been an uphill task owing to their large size and complex domain organization. Recent advances in mammalian protein expression/purification and cryo-EM-based structure determination have led to significant progress in our understanding of these large multidomain proteins. This review is an overview of the structural principles that underlie some of the key signaling proteins that function at the double-strand break site. We also discuss some plausible ideas that could be considered for future structural approaches to visualize and build a more complete understanding of protein dynamics at the break site.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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Hepburn M, Saltzberg DJ, Lee L, Fang S, Atkinson C, Strynadka NCJ, Sali A, Lees-Miller SP, Schriemer DC. The active DNA-PK holoenzyme occupies a tensed state in a staggered synaptic complex. Structure 2021; 29:467-478.e6. [PMID: 33412091 DOI: 10.1016/j.str.2020.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/14/2020] [Accepted: 12/09/2020] [Indexed: 01/06/2023]
Abstract
In the non-homologous end-joining (NHEJ) of a DNA double-strand break, DNA ends are bound and protected by DNA-PK, which synapses across the break to tether the broken ends and initiate repair. There is little clarity surrounding the nature of the synaptic complex and the mechanism governing the transition to repair. We report an integrative structure of the synaptic complex at a precision of 13.5 Å, revealing a symmetric head-to-head arrangement with a large offset in the DNA ends and an extensive end-protection mechanism involving a previously uncharacterized plug domain. Hydrogen/deuterium exchange mass spectrometry identifies an allosteric pathway connecting DNA end-binding with the kinase domain that places DNA-PK under tension in the kinase-active state. We present a model for the transition from end-protection to repair, where the synaptic complex supports hierarchical processing of the ends and scaffold assembly, requiring displacement of the catalytic subunit and tension release through kinase activity.
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Affiliation(s)
- Morgan Hepburn
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Daniel J Saltzberg
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, CA 94158, USA
| | - Linda Lee
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Shujuan Fang
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Claire Atkinson
- Department of Biochemistry and Molecular Biology and High-Resolution Macromolecular Electron Microscopy Facility, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and High-Resolution Macromolecular Electron Microscopy Facility, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, CA 94158, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada; Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada; Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada; Department of Chemistry, University of Calgary, Calgary, AB, Canada.
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Yu L, Lang Y, Guo J, Cai J, Shang ZF, Chen BPC. DNA-PKcs inhibition impairs HDAC6-mediated HSP90 chaperone function on Aurora A and enhances HDACs inhibitor-induced cell killing by increasing mitotic aberrant spindle assembly. Cell Cycle 2021; 20:211-224. [PMID: 33404279 DOI: 10.1080/15384101.2020.1867790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Combining targeted therapeutic agents is an attractive cancer treatment strategy associated with high efficacy and low toxicity. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is an essential factor in DNA damage repair. Studies from us and others have revealed that DNA-PKcs also plays an important role in normal mitosis progression. Histone deacetylase (HDACs) inhibitors commonly lead to mitotic aberration and have been approved for treating various cancers in the clinic. We showed that DNA-PKcs depletion or kinase activity inhibition increases cancer cells' sensitivity to HDACs inhibitors in vitro and in vivo. DNA-PKcs deficiency significantly enhances HDACs inhibitors (HDACi)-induced mitotic arrest and is followed by apoptotic cell death. Mechanistically, we found that DNA-PKcs binds to HDAC6 and facilitates its acetylase activity. HDACi is more likely to impair HDAC6-induced deacetylation of HSP90 and abrogate HSP90's chaperone function on Aurora A, a critical mitotic kinase that regulates centrosome separation and mitotic spindle assembly in DNA-PKcs-deficient cells. Our current work indicates crosstalk between DNA-PKcs and HDACs signaling pathways, and highlights that the combined targeting of DNA-PKcs and HDACs can be used in cancer therapy. Abbreviations: DNA-PKcs, DNA-dependent protein kinase catalytic subunit, HDACs, Histone deacetylases, DSBs, DNA double-strand breaks, ATM, ataxia telangiectasia mutated, ATR, ATM-Rad3-related.
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Affiliation(s)
- Lan Yu
- Department of Radiation Oncology, Simmons Comprehensive Cancer Center at UT Southwestern Medical Center , Dallas, TX, USA
| | - Yue Lang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University , Suzhou, China
| | - Jiaming Guo
- Department of Radiation Oncology, Simmons Comprehensive Cancer Center at UT Southwestern Medical Center , Dallas, TX, USA.,Department of Radiation Medicine, College of Naval Medicine, Naval Medical University , Shanghai, China
| | - Jianming Cai
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University , Shanghai, China
| | - Zeng-Fu Shang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University , Suzhou, China
| | - Benjamin P C Chen
- Department of Radiation Oncology, Simmons Comprehensive Cancer Center at UT Southwestern Medical Center , Dallas, TX, USA
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Johnson MA, Deng Q, Taylor G, McEachin ZT, Chan AWS, Root J, Bassell GJ, Kukar T. Divergent FUS phosphorylation in primate and mouse cells following double-strand DNA damage. Neurobiol Dis 2020; 146:105085. [PMID: 32950644 PMCID: PMC8064403 DOI: 10.1016/j.nbd.2020.105085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Fused in sarcoma (FUS) is a RNA/DNA protein involved in multiple nuclear and cytoplasmic functions including transcription, splicing, mRNA trafficking, and stress granule formation. To accomplish these many functions, FUS must shuttle between cellular compartments in a highly regulated manner. When shuttling is disrupted, FUS abnormally accumulates into cytoplasmic inclusions that can be toxic. Disrupted shuttling of FUS into the nucleus is a hallmark of ~10% of frontotemporal lobar degeneration (FTLD) cases, the neuropathology that underlies frontotemporal dementia (FTD). Multiple pathways are known to disrupt nuclear/cytoplasmic shuttling of FUS. In earlier work, we discovered that double-strand DNA breaks (DSBs) trigger DNA-dependent protein kinase (DNA-PK) to phosphorylate FUS (p-FUS) at N-terminal residues leading to the cytoplasmic accumulation of FUS. Therefore, DNA damage may contribute to the development of FTLD pathology with FUS inclusions. In the present study, we examined how DSBs effect FUS phosphorylation in various primate and mouse cellular models. All cell lines derived from human and non-human primates exhibit N-terminal FUS phosphorylation following calicheamicin γ1 (CLM) induced DSBs. In contrast, we were unable to detect FUS phosphorylation in mouse-derived primary neurons or immortalized cell lines regardless of CLM treatment, duration, or concentration. Despite DNA damage induced by CLM treatment, we find that mouse cells do not phosphorylate FUS, likely due to reduced levels and activity of DNA-PK compared to human cells. Taken together, our work reveals that mouse-derived cellular models regulate FUS in an anomalous manner compared to primate cells. This raises the possibility that mouse models may not fully recapitulate the pathogenic cascades that lead to FTLD with FUS pathology.
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Affiliation(s)
- Michelle A Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Qiudong Deng
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Georgia Taylor
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Zachary T McEachin
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Anthony W S Chan
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA, United States of America; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, 954 Gatewood Rd, NE, Atlanta, GA, United States of America
| | - Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Gary J Bassell
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Neurology, Emory University, School of Medicine, Atlanta, GA, United States of America.
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DNA-PKcs phosphorylation at the T2609 cluster alters the repair pathway choice during immunoglobulin class switch recombination. Proc Natl Acad Sci U S A 2020; 117:22953-22961. [PMID: 32868446 DOI: 10.1073/pnas.2007455117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The DNA-dependent protein kinase (DNA-PK), which is composed of the KU heterodimer and the large catalytic subunit (DNA-PKcs), is a classical nonhomologous end-joining (cNHEJ) factor. Naïve B cells undergo class switch recombination (CSR) to generate antibodies with different isotypes by joining two DNA double-strand breaks at different switching regions via the cNHEJ pathway. DNA-PK and the cNHEJ pathway play important roles in the DNA repair phase of CSR. To initiate cNHEJ, KU binds to DNA ends and recruits and activates DNA-PK. Activated DNA-PK phosphorylates DNA-PKcs at the S2056 and T2609 clusters. Loss of T2609 cluster phosphorylation increases radiation sensitivity but whether T2609 phosphorylation has a role in physiological DNA repair remains elusive. Using the DNA-PKcs 5A mouse model carrying alanine substitutions at the T2609 cluster, here we show that loss of T2609 phosphorylation of DNA-PKcs does not affect the CSR efficiency. Yet, the CSR junctions recovered from DNA-PKcs 5A/5A B cells reveal increased chromosomal translocations, extensive use of distal switch regions (consistent with end resection), and preferential usage of microhomology-all signs of the alternative end-joining pathway. Thus, these results uncover a role of DNA-PKcs T2609 phosphorylation in promoting cNHEJ repair pathway choice during CSR.
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Lafont F, Fleury F, Benhelli-Mokrani H. DNA-PKcs Ser2056 auto-phosphorylation is affected by an O-GlcNAcylation/phosphorylation interplay. Biochim Biophys Acta Gen Subj 2020; 1864:129705. [PMID: 32805318 DOI: 10.1016/j.bbagen.2020.129705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/17/2020] [Accepted: 08/04/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND DNA dependent Protein Kinase (DNA-PK) is an heterotrimeric complex regulating the Non Homologous End Joining (NHEJ) double strand break (DSB) repair pathway. The activity of its catalytic subunit (DNA-PKcs) is regulated by multiple phosphorylations, like the Ser2056 one that impacts DSB end processing and telomeres integrity. O-GlcNAcylation is a post translational modification (PTM) closely related to phosphorylation and its implication in the modulation of DNA-PKcs activity during the DNA Damage Response (DDR) is unknown. METHODS Using IP techniques, and HeLa cell line, we evaluated the effect of pharmacological or siOGT mediated O-GlcNAc level modulation on DNA-PKcs O-GlcNAcylation. We used the RPA32 phosphorylation as a DNA-PKcs activity reporter substrate to evaluate the effect of O-GlcNAc modulators. RESULTS We show here that human DNA-PKcs is an O-GlcNAc modified protein and that this new PTM is responsive to the cell O-GlcNAcylation level modulation. Our findings reveal that DNA-PKcs hypo O-GlcNAcylation affects its kinase activity and that the bleomycin-induced Ser2056 phosphorylation, is modulated by DNA-PKcs O-GlcNAcylation. CONCLUSIONS DNA-PKcs Ser2056 phosphorylation is antagonistically linked to DNA-PKcs O-GlcNAcylation level modulation. GENERAL SIGNIFICANCE Given the essential role of DNA-PKcs Ser2056 phosphorylation in the DDR, this study brings data about the role of cell O-GlcNAc level on genome integrity maintenance.
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Affiliation(s)
- Florian Lafont
- Université de Nantes, CNRS, UFIP, UMR 6286, 44000 Nantes, France
| | - Fabrice Fleury
- Université de Nantes, CNRS, UFIP, UMR 6286, 44000 Nantes, France
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DNA double-strand break end resection: a critical relay point for determining the pathway of repair and signaling. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s42764-020-00017-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
AbstractA DNA double-strand break (DSB) is considered the most critical DNA lesion because it causes cell death and severe mutations if it is not repaired or repaired incorrectly. Accumulating evidence has shown that the majority of DSBs are repaired by DNA non-homologous end joining (NHEJ), the first utilized repair pathway in human cells. In contrast, the repair pathway is sometimes diverted into using homologous recombination (HR), which has increased precision under specific circumstances: e.g., when DSBs are generated at transcriptionally active loci or are not readily repaired due to the complexity of damage at the DSB ends or due to highly compacted chromatin. DSB end resection (resection) is considered the most critical turning point for directing repair towards HR. After resection, the HR process is finalized by RAD51 loading and recombination. Thus, understanding the process of resection is critically important to understand the regulation of the choice of DSB repair pathway. In addition, resection is also an important factor influencing DNA damage signaling because unresected ends preferentially activate ATM, whereas longer resected ends activate ATR. Thus, DSB end resection is a key relay point that determines the repair pathway and the signal balance. In this review, we summarize the mechanism underlying DSB end resection and further discuss how it is involved in cancer therapy.
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Triptolide impairs genome integrity by directly blocking the enzymatic activity of DNA-PKcs in human cells. Biomed Pharmacother 2020; 129:110427. [PMID: 32574974 DOI: 10.1016/j.biopha.2020.110427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/09/2020] [Accepted: 06/13/2020] [Indexed: 01/02/2023] Open
Abstract
Triptolide is a multi-functional natural small molecular compound extracted from a traditional Chinese medicinal herb. Triptolide and its derivatives exhibit cytotoxicity through inducing DNA damage, therefore increasing sensitivity to DNA-damage based chemotherapy or radiotherapy in different types of cells. However, the regulatory mechanism of genotoxicity by triptolide, and the loss of genome integrity induced by triptolide are not fully understood. Here, we measured the effects of triptolide on genome integrity in a human fibroblast line HCA2-hTERT using the neutral comet assay. We demonstrated that treating cells with triptolide induced genomic instability in HCA2-hTERT cells. Furthermore, we observed the accumulation of γH2AX foci in triptolide treated cells than control cells at 24 h post ionizing radiation. Further mechanistic studies indicated that triptolide inhibited the enzymatic activity of DNA-PKcs, the critical nonhomologous end joining factor. In vitro kinase activity assays showed that triptolide suppressed the kinase activity of DNA-PKcs and molecular docking also predicted a potential interaction between triptolide and DNA-PKcs. As a consequence, we found that triptolide treatment enhanced the interaction between DNA-PKcs and KU80 and hampered the following recruitment of 53BP1. Altogether, our finding provides a new perspective about the toxicity of triptolide in non-cancer cells and highlights the necessity of taking genome effects of triptolide and its derivatives into consideration in the future clinical and research applications.
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Jiang W, Estes VM, Wang XS, Shao Z, Lee BJ, Lin X, Crowe JL, Zha S. Phosphorylation at S2053 in Murine (S2056 in Human) DNA-PKcs Is Dispensable for Lymphocyte Development and Class Switch Recombination. THE JOURNAL OF IMMUNOLOGY 2019; 203:178-187. [PMID: 31101667 DOI: 10.4049/jimmunol.1801657] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/22/2019] [Indexed: 11/19/2022]
Abstract
The classical nonhomologous end-joining (cNHEJ) pathway is a major DNA double-strand break repair pathway in mammalian cells and is required for lymphocyte development and maturation. The DNA-dependent protein kinase (DNA-PK) is a cNHEJ factor that encompasses the Ku70-Ku80 (KU) heterodimer and the large DNA-PK catalytic subunit (DNA-PKcs). In mouse models, loss of DNA-PKcs (DNA-PKcs-/- ) abrogates end processing (e.g., hairpin opening), but not end-ligation, whereas expression of the kinase-dead DNA-PKcs protein (DNA-PKcsKD/KD ) abrogates end-ligation, suggesting a kinase-dependent structural function of DNA-PKcs during cNHEJ. Lymphocyte development is abolished in DNA-PKcs-/- and DNA-PKcsKD/KD mice because of the requirement for both hairpin opening and end-ligation during V(D)J recombination. DNA-PKcs itself is the best-characterized substrate of DNA-PK. The S2056 cluster is the best-characterized autophosphorylation site in human DNA-PKcs. In this study, we show that radiation can induce phosphorylation of murine DNA-PKcs at the corresponding S2053. We also generated knockin mouse models with alanine- (DNA-PKcsPQR) or phospho-mimetic aspartate (DNA-PKcsSD) substitutions at the S2053 cluster. Despite moderate radiation sensitivity in the DNA-PKcsPQR/PQR fibroblasts and lymphocytes, both DNA-PKcsPQR/PQR and DNA-PKcsSD/SD mice retained normal kinase activity and underwent efficient V(D)J recombination and class switch recombination, indicating that phosphorylation at the S2053 cluster of murine DNA-PKcs (corresponding to S2056 of human DNA-PKcs), although important for radiation resistance, is dispensable for the end-ligation and hairpin-opening function of DNA-PK essential for lymphocyte development.
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Affiliation(s)
- Wenxia Jiang
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Verna M Estes
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Xiaobin S Wang
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032.,Graduate Program of Pathobiology and Molecular Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Zhengping Shao
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Brian J Lee
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Xiaohui Lin
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Jennifer L Crowe
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032.,Graduate Program of Pathobiology and Molecular Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Shan Zha
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032; .,Division of Pediatric Oncology, Hematology and Stem Cell Transplantation, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032; and.,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032
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12
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Wu L, He Y, Hu Y, Lu H, Cao Z, Yi X, Wang J. Real-time surface plasmon resonance monitoring of site-specific phosphorylation of p53 protein and its interaction with MDM2 protein. Analyst 2019; 144:6033-6040. [DOI: 10.1039/c9an01121h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Real-time monitoring of site-specific phosphorylation of p53 protein and its binding to MDM2 is conducted using dual-channel surface plasmon resonance (SPR).
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Affiliation(s)
- Ling Wu
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
| | - Yuhan He
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
| | - Yuqing Hu
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
| | - Hanwen Lu
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
| | - Zhong Cao
- Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation
- School of Chemistry and Biological Engineering
- Changsha University of Science and Technology
- Changsha
- P. R. China 410114
| | - Xinyao Yi
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
| | - Jianxiu Wang
- College of Chemistry and Chemical Engineering
- Central South University
- Changsha
- P. R. China 410083
- Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety
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13
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Liu X, Li P, Hirayama R, Niu Y, Liu X, Chen W, Jin X, Zhang P, Ye F, Zhao T, Liu B, Li Q. Genistein sensitizes glioblastoma cells to carbon ions via inhibiting DNA-PKcs phosphorylation and subsequently repressing NHEJ and delaying HR repair pathways. Radiother Oncol 2018; 129:84-94. [PMID: 29685705 DOI: 10.1016/j.radonc.2018.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/22/2018] [Accepted: 04/04/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE Previously, we found genistein could sensitize cancer cells to low linear energy transfer (LET) X-rays via inhibiting DNA-PKcs activities. Especially, high-LET heavy ion produces more DNA double strand breaks (DSBs) than low-LET radiation. Thus, the study was designed to investigate the detailed molecular mechanisms of genistein on sensitizing cancer cells to heavy ions. MATERIALS AND METHODS Human glioblastoma (GBM) cell lines with or without genistein pre-treatment were irradiated with high-LET carbon ions. Cell survival was determined with colony formation assay. DNA DSBs were evaluated by means of detecting γ-H2AX foci and immuno-blotting DSB repair proteins, cell apoptosis was detected using Annexin V and PI staining. The interaction of genistein with DNA-PKcs activation site was estimated by molecular docking in the autodock software. RESULTS Genistein sensitized DNA-PKcs proficient GBM cells to high-LET carbon ions via delaying the clearance of γ-H2AX foci. Genistein was physically bound to DNA-PKcs and functionally inhibited the phosphorylation of DNA-PKcs. Consequently, the non-homologous end joining (NHEJ) repair of DSBs was inhibited and the homologous recombination (HR) repair was delayed by genistein, thereby leading to an increase in apoptosis in DNA-PKcs proficient GBM cells after irradiation. CONCLUSION Our study demonstrated that genistein holds promise as a radiosensitizer for enhancing the efficacy of carbon ion radiotherapy against DNA-PKcs proficient GBM via inhibiting DNA-PKcs phosphorylation and subsequently repressing NHEJ and delaying HR repair pathways.
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Affiliation(s)
- Xiongxiong Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ping Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ryoichi Hirayama
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Yuzhen Niu
- Shandong Provincial Research Center for Bioinformatic Engineering and Technique, School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Xinguo Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Weiqiang Chen
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Xiaodong Jin
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Pengcheng Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fei Ye
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ting Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Bingtao Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China.
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14
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Lees-Miller SP, Beattie TL, Tainer JA. Noncoding RNA joins Ku and DNA-PKcs for DNA-break resistance in breast cancer. Nat Struct Mol Biol 2017; 23:509-10. [PMID: 27273637 DOI: 10.1038/nsmb.3240] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Tara L Beattie
- Department of Biochemistry and Molecular Biology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - John A Tainer
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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15
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Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with no known cure that affects at least five million people worldwide. Monozygotic twin concordance and familial aggregation studies strongly suggest that lupus results from genetic predisposition along with environmental exposures including UV light. The majority of the common risk alleles associated with genetic predisposition to SLE map to genes associated with the immune system. However, evidence is emerging that implicates a role for aberrant DNA repair in the development of lupus. Here we summarize our current knowledge of the potential association of lupus with mutations in DNA repair genes. We also discuss how defective or aberrant DNA repair could lead to the development of lupus.
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Affiliation(s)
- Rithy Meas
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Matthew J Burak
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Joann B Sweasy
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA; Department of Genetics, Yale University, New Haven, CT, USA.
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16
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Brosey CA, Ahmed Z, Lees-Miller SP, Tainer JA. What Combined Measurements From Structures and Imaging Tell Us About DNA Damage Responses. Methods Enzymol 2017; 592:417-455. [PMID: 28668129 DOI: 10.1016/bs.mie.2017.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
DNA damage outcomes depend upon the efficiency and fidelity of DNA damage responses (DDRs) for different cells and damage. As such, DDRs represent tightly regulated prototypical systems for linking nanoscale biomolecular structure and assembly to the biology of genomic regulation and cell signaling. However, the dynamic and multifunctional nature of DDR assemblies can render elusive the correlation between the structures of DDR factors and specific biological disruptions to the DDR when these structures are altered. In this chapter, we discuss concepts and strategies for combining structural, biophysical, and imaging techniques to investigate DDR recognition and regulation, and thus bridge sequence-level structural biochemistry to quantitative biological outcomes visualized in cells. We focus on representative DDR responses from PARP/PARG/AIF damage signaling in DNA single-strand break repair and nonhomologous end joining complexes in double-strand break repair. Methods with exemplary experimental results are considered with a focus on strategies for probing flexibility, conformational changes, and assembly processes that shape a predictive understanding of DDR mechanisms in a cellular context. Integration of structural and imaging measurements promises to provide foundational knowledge to rationally control and optimize DNA damage outcomes for synthetic lethality and for immune activation with resulting insights for biology and cancer interventions.
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Affiliation(s)
- Chris A Brosey
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Zamal Ahmed
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Susan P Lees-Miller
- Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada.
| | - John A Tainer
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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17
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Lysines 3241 and 3260 of DNA-PKcs are important for genomic stability and radioresistance. Biochem Biophys Res Commun 2016; 477:235-40. [PMID: 27297111 DOI: 10.1016/j.bbrc.2016.06.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 11/22/2022]
Abstract
DNA-dependent protein kinase (DNA-PK) is a serine/threonine kinase that plays an essential role in the repair of DNA double-strand breaks (DSBs) in the non-homologous end-joining (NHEJ) pathway. The DNA-PK holoenzyme consists of a catalytic subunit (DNA-PKcs) and DNA-binding subunit (Ku70/80, Ku). Ku is a molecular sensor for double-stranded DNA and once bound to DSB ends it recruits DNA-PKcs to the DSB site. Subsequently, DNA-PKcs is activated and heavily phosphorylated, with these phosphorylations modulating DNA-PKcs. Although phosphorylation of DNA-PKcs is well studied, other post-translational modifications of DNA-PKcs are not. In this study, we aimed to determine if acetylation of DNA-PKcs regulates DNA-PKcs-dependent DSB repair. We report that DNA-PKcs is acetylated in vivo and identified two putative acetylation sites, lysine residues 3241 and 3260. Mutating these sites to block potential acetylation results in increased radiosensitive, a slight decrease in DSB repair capacity as assessed by γH2AX resolution, and increased chromosomal aberrations, especially quadriradial chromosomes. Together, our results provide evidence that acetylation potentially regulates DNA-PKcs.
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18
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Liu XX, Sun C, Jin XD, Li P, Zheng XG, Zhao T, Li Q. Genistein sensitizes sarcoma cells in vitro and in vivo by enhancing apoptosis and by inhibiting DSB repair pathways. JOURNAL OF RADIATION RESEARCH 2016; 57:227-237. [PMID: 26922091 PMCID: PMC4915536 DOI: 10.1093/jrr/rrv091] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/03/2015] [Accepted: 11/03/2015] [Indexed: 06/05/2023]
Abstract
The aim of this work was to investigate the radiosensitization effects of genistein on mice sarcoma cells and the corresponding biological mechanisms in vitro and in vivo Using the non-toxic dosage of 10 μM genistein, the sensitizer enhancement ratios after exposure to X-rays at 50% cell survival (IC50) was 1.45 for S180 cells. For mice cotreated with genistein and X-rays, the excised tumor tissues had reduced blood vessels and decreased size and volume compared with the control and irradiation-only groups. Moreover, a significant increase in apoptosis was accompanied by upregulation of Bax and downregulation of Bcl-2 in the mitochondria, and lots of cytochrome c being transferred to the cytoplasm. Furthermore, X-rays combined with genistein inhibited the activity of DNA-PKcs, so DNA-injured sites were dominated by Ku70/80, leading to incompleteness of homologous recombination (HR) and non-homologous end-joining (NHEJ) repairs and the eventual occurrence of cell apoptosis. Our study, for the first time, demonstrated that genistein sensitized sarcoma cells to X-rays and that this radiosensitizing effect depended on induction of the mitochondrial apoptosis pathway and inhibition of the double-strand break (DSB) repair pathways.
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Affiliation(s)
- X X Liu
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
| | - C Sun
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
| | - X D Jin
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
| | - P Li
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
| | - X G Zheng
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - T Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
| | - Q Li
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, Gansu Province, China Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China
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19
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Affiliation(s)
- Anna Uryga
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; ,
| | - Kelly Gray
- Cardiovascular Safety, AstraZeneca, Cambridge CB4 0FZ, United Kingdom;
| | - Martin Bennett
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; ,
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20
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Caron P, Choudjaye J, Clouaire T, Bugler B, Daburon V, Aguirrebengoa M, Mangeat T, Iacovoni JS, Álvarez-Quilón A, Cortés-Ledesma F, Legube G. Non-redundant Functions of ATM and DNA-PKcs in Response to DNA Double-Strand Breaks. Cell Rep 2015; 13:1598-609. [PMID: 26586426 PMCID: PMC4670905 DOI: 10.1016/j.celrep.2015.10.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 09/04/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022] Open
Abstract
DNA double-strand breaks (DSBs) elicit the so-called DNA damage response (DDR), largely relying on ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PKcs), two members of the PI3K-like kinase family, whose respective functions during the sequential steps of the DDR remains controversial. Using the DIvA system (DSB inducible via AsiSI) combined with high-resolution mapping and advanced microscopy, we uncovered that both ATM and DNA-PKcs spread in cis on a confined region surrounding DSBs, independently of the pathway used for repair. However, once recruited, these kinases exhibit non-overlapping functions on end joining and γH2AX domain establishment. More specifically, we found that ATM is required to ensure the association of multiple DSBs within "repair foci." Our results suggest that ATM acts not only on chromatin marks but also on higher-order chromatin organization to ensure repair accuracy and survival.
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Affiliation(s)
- Pierre Caron
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jonathan Choudjaye
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Clouaire
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Béatrix Bugler
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Virginie Daburon
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Marion Aguirrebengoa
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Mangeat
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jason S Iacovoni
- Bioinformatic Plateau I2MC, INSERM and University of Toulouse, 1 Avenue Jean Poulhes, BP 84225, 31432 Toulouse Cedex 4, France
| | - Alejandro Álvarez-Quilón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Felipe Cortés-Ledesma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Gaëlle Legube
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France.
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21
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Lavin MF, Kozlov S, Gatei M, Kijas AW. ATM-Dependent Phosphorylation of All Three Members of the MRN Complex: From Sensor to Adaptor. Biomolecules 2015; 5:2877-902. [PMID: 26512707 PMCID: PMC4693261 DOI: 10.3390/biom5042877] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 11/16/2022] Open
Abstract
The recognition, signalling and repair of DNA double strand breaks (DSB) involves the participation of a multitude of proteins and post-translational events that ensure maintenance of genome integrity. Amongst the proteins involved are several which when mutated give rise to genetic disorders characterised by chromosomal abnormalities, cancer predisposition, neurodegeneration and other pathologies. ATM (mutated in ataxia-telangiectasia (A-T) and members of the Mre11/Rad50/Nbs1 (MRN complex) play key roles in this process. The MRN complex rapidly recognises and locates to DNA DSB where it acts to recruit and assist in ATM activation. ATM, in the company of several other DNA damage response proteins, in turn phosphorylates all three members of the MRN complex to initiate downstream signalling. While ATM has hundreds of substrates, members of the MRN complex play a pivotal role in mediating the downstream signalling events that give rise to cell cycle control, DNA repair and ultimately cell survival or apoptosis. Here we focus on the interplay between ATM and the MRN complex in initiating signaling of breaks and more specifically on the adaptor role of the MRN complex in mediating ATM signalling to downstream substrates to control different cellular processes.
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Affiliation(s)
- Martin F Lavin
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Sergei Kozlov
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Magtouf Gatei
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Amanda W Kijas
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
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22
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LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 and 1880=1880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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23
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LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 1-- #] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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24
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LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 8029-- -] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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25
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LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015; 6:8325. [PMID: 26446488 PMCID: PMC4633636 DOI: 10.1038/ncomms9325] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 08/11/2015] [Indexed: 12/29/2022] Open
Abstract
Leukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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26
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LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 8029-- #] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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Liu XS, Chandramouly G, Rass E, Guan Y, Wang G, Hobbs RM, Rajendran A, Xie A, Shah JV, Davis AJ, Scully R, Lunardi A, Pandolfi PP. LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 1-- -] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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Liu XS, Chandramouly G, Rass E, Guan Y, Wang G, Hobbs RM, Rajendran A, Xie A, Shah JV, Davis AJ, Scully R, Lunardi A, Pandolfi PP. LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 1-- gadu] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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Liu XS, Chandramouly G, Rass E, Guan Y, Wang G, Hobbs RM, Rajendran A, Xie A, Shah JV, Davis AJ, Scully R, Lunardi A, Pandolfi PP. LRF maintains genome integrity by regulating the non-homologous end joining pathway of DNA repair. Nat Commun 2015. [DOI: 10.1038/ncomms9325 order by 8029-- awyx] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
AbstractLeukemia/lymphoma-related factor (LRF) is a POZ/BTB and Krüppel (POK) transcriptional repressor characterized by context-dependent key roles in cell fate decision and tumorigenesis. Here we demonstrate an unexpected transcription-independent function for LRF in the classical non-homologous end joining (cNHEJ) pathway of double-strand break (DSB) repair. We find that LRF loss in cell lines and mouse tissues results in defective cNHEJ, genomic instability and hypersensitivity to ionizing radiation. Mechanistically, we show that LRF binds and stabilizes DNA-PKcs on DSBs, in turn favouring DNA-PK activity. Importantly, LRF loss restores ionizing radiation sensitivity to p53 null cells, making LRF an attractive biomarker to direct p53-null LRF-deficient tumours towards therapeutic treatments based on genotoxic agents or PARP inhibitors following a synthetic lethal strategy.
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XRCC4/XLF Interaction Is Variably Required for DNA Repair and Is Not Required for Ligase IV Stimulation. Mol Cell Biol 2015; 35:3017-28. [PMID: 26100018 DOI: 10.1128/mcb.01503-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 06/15/2015] [Indexed: 01/21/2023] Open
Abstract
The classic nonhomologous end-joining (c-NHEJ) pathway is largely responsible for repairing double-strand breaks (DSBs) in mammalian cells. XLF stimulates the XRCC4/DNA ligase IV complex by an unknown mechanism. XLF interacts with XRCC4 to form filaments of alternating XRCC4 and XLF dimers that bridge DNA ends in vitro, providing a mechanism by which XLF might stimulate ligation. Here, we characterize two XLF mutants that do not interact with XRCC4 and cannot form filaments or bridge DNA in vitro. One mutant is fully sufficient in stimulating ligation by XRCC4/Lig4 in vitro; the other is not. This separation-of-function mutant (which must function as an XLF homodimer) fully complements the c-NHEJ deficits of some XLF-deficient cell strains but not others, suggesting a variable requirement for XRCC4/XLF interaction in living cells. To determine whether the lack of XRCC4/XLF interaction (and potential bridging) can be compensated for by other factors, candidate repair factors were disrupted in XLF- or XRCC4-deficient cells. The loss of either ATM or the newly described XRCC4/XLF-like factor, PAXX, accentuates the requirement for XLF. However, in the case of ATM/XLF loss (but not PAXX/XLF loss), this reflects a greater requirement for XRCC4/XLF interaction.
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Heo J, Li J, Summerlin M, Hays A, Katyal S, McKinnon PJ, Nitiss KC, Nitiss JL, Hanakahi LA. TDP1 promotes assembly of non-homologous end joining protein complexes on DNA. DNA Repair (Amst) 2015; 30:28-37. [PMID: 25841101 DOI: 10.1016/j.dnarep.2015.03.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 02/25/2015] [Accepted: 03/09/2015] [Indexed: 11/16/2022]
Abstract
The repair of DNA double-strand breaks (DSB) is central to the maintenance of genomic integrity. In tumor cells, the ability to repair DSBs predicts response to radiation and many cytotoxic anti-cancer drugs. DSB repair pathways include homologous recombination and non-homologous end joining (NHEJ). NHEJ is a template-independent mechanism, yet many NHEJ repair products carry limited genetic changes, which suggests that NHEJ includes mechanisms to minimize error. Proteins required for mammalian NHEJ include Ku70/80, the DNA-dependent protein kinase (DNA-PKcs), XLF/Cernunnos and the XRCC4:DNA ligase IV complex. NHEJ also utilizes accessory proteins that include DNA polymerases, nucleases, and other end-processing factors. In yeast, mutations of tyrosyl-DNA phosphodiesterase (TDP1) reduced NHEJ fidelity. TDP1 plays an important role in repair of topoisomerase-mediated DNA damage and 3'-blocking DNA lesions, and mutation of the human TDP1 gene results in an inherited human neuropathy termed SCAN1. We found that human TDP1 stimulated DNA binding by XLF and physically interacted with XLF to form TDP1:XLF:DNA complexes. TDP1:XLF interactions preferentially stimulated TDP1 activity on dsDNA as compared to ssDNA. TDP1 also promoted DNA binding by Ku70/80 and stimulated DNA-PK activity. Because Ku70/80 and XLF are the first factors recruited to the DSB at the onset of NHEJ, our data suggest a role for TDP1 during the early stages of mammalian NHEJ.
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Affiliation(s)
- Jinho Heo
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - Jing Li
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - Matthew Summerlin
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - Annette Hays
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - Sachin Katyal
- University of Manitoba, Department of Pharmacology and Therapeutics, Manitoba Institute of Cell Biology, 675 McDermot Avenue, Winnipeg, Manitoba, Canada R3E 0V9
| | - Peter J McKinnon
- Department of Genetics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Karin C Nitiss
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - John L Nitiss
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA
| | - Leslyn A Hanakahi
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA; Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, IL 61107, USA.
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Abstract
UNLABELLED The DNA-dependent protein kinase (DNA-PK) is a pivotal component of the DNA repair machinery that governs the response to DNA damage, serving to maintain genome integrity. However, the DNA-PK kinase component was initially isolated with transcriptional complexes, and recent findings have illuminated the impact of DNA-PK-mediated transcriptional regulation on tumor progression and therapeutic response. DNA-PK expression has also been correlated with poor outcome in selected tumor types, further underscoring the importance of understanding its role in disease. Herein, the molecular and cellular consequences of DNA-PK are considered, with an eye toward discerning the rationale for therapeutic targeting of DNA-PK. SIGNIFICANCE Although DNA-PK is classically considered a component of damage response, recent findings illuminate damage-independent functions of DNA-PK that affect multiple tumor-associated pathways and provide a rationale for the development of novel therapeutic strategies.
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Affiliation(s)
- Jonathan F Goodwin
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Karen E Knudsen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania. Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania. Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania. Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
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Abstract
UNLABELLED The DNA-dependent protein kinase (DNA-PK) is a pivotal component of the DNA repair machinery that governs the response to DNA damage, serving to maintain genome integrity. However, the DNA-PK kinase component was initially isolated with transcriptional complexes, and recent findings have illuminated the impact of DNA-PK-mediated transcriptional regulation on tumor progression and therapeutic response. DNA-PK expression has also been correlated with poor outcome in selected tumor types, further underscoring the importance of understanding its role in disease. Herein, the molecular and cellular consequences of DNA-PK are considered, with an eye toward discerning the rationale for therapeutic targeting of DNA-PK. SIGNIFICANCE Although DNA-PK is classically considered a component of damage response, recent findings illuminate damage-independent functions of DNA-PK that affect multiple tumor-associated pathways and provide a rationale for the development of novel therapeutic strategies.
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Affiliation(s)
- Jonathan F Goodwin
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Karen E Knudsen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania. Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania. Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania. Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
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Woodbine L, Gennery AR, Jeggo PA. Reprint of "The clinical impact of deficiency in DNA non-homologous end-joining". DNA Repair (Amst) 2014; 17:9-20. [PMID: 24780557 DOI: 10.1016/j.dnarep.2014.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 01/10/2023]
Abstract
DNA non-homologous end-joining (NHEJ) is the major DNA double strand break (DSB) repair pathway in mammalian cells. Defects in NHEJ proteins confer marked radiosensitivity in cell lines and mice models, since radiation potently induces DSBs. The process of V(D)J recombination functions during the development of the immune response, and involves the introduction and rejoining of programmed DSBs to generate an array of diverse T and B cells. NHEJ rejoins these programmed DSBs. Consequently, NHEJ deficiency confers (severe) combined immunodeficiency - (S)CID - due to a failure to carry out V(D)J recombination efficiently. NHEJ also functions in class switch recombination, another step enhancing T and B cell diversity. Prompted by these findings, a search for radiosensitivity amongst (S)CID patients revealed a radiosensitive sub-class, defined as RS-SCID. Mutations in NHEJ genes, defining human syndromes deficient in DNA ligase IV (LIG4 Syndrome), XLF-Cernunnos, Artemis or DNA-PKcs, have been identified in such patients. Mutations in XRCC4 or Ku70,80 in patients have not been identified. RS-SCID patients frequently display additional characteristics including microcephaly, dysmorphic facial features and growth delay. Here, we overview the clinical spectrum of RS-SCID patients and discuss our current understanding of the underlying biology.
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Affiliation(s)
- Lisa Woodbine
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Andrew R Gennery
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Penny A Jeggo
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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35
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DNA-PK: a dynamic enzyme in a versatile DSB repair pathway. DNA Repair (Amst) 2014; 17:21-9. [PMID: 24680878 DOI: 10.1016/j.dnarep.2014.02.020] [Citation(s) in RCA: 260] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 02/17/2014] [Accepted: 02/24/2014] [Indexed: 11/23/2022]
Abstract
DNA double stranded breaks (DSBs) are the most cytoxic DNA lesion as the inability to properly repair them can lead to genomic instability and tumorigenesis. The prominent DSB repair pathway in humans is non-homologous end-joining (NHEJ). In the simplest sense, NHEJ mediates the direct re-ligation of the broken DNA molecule. However, NHEJ is a complex and versatile process that can repair DSBs with a variety of damages and ends via the utilization of a significant number of proteins. In this review we will describe the important factors and mechanisms modulating NHEJ with emphasis given to the versatility of this repair process and the DNA-PK complex.
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Woodbine L, Gennery AR, Jeggo PA. The clinical impact of deficiency in DNA non-homologous end-joining. DNA Repair (Amst) 2014; 16:84-96. [PMID: 24629483 DOI: 10.1016/j.dnarep.2014.02.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 12/22/2022]
Abstract
DNA non-homologous end-joining (NHEJ) is the major DNA double strand break (DSB) repair pathway in mammalian cells. Defects in NHEJ proteins confer marked radiosensitivity in cell lines and mice models, since radiation potently induces DSBs. The process of V(D)J recombination functions during the development of the immune response, and involves the introduction and rejoining of programmed DSBs to generate an array of diverse T and B cells. NHEJ rejoins these programmed DSBs. Consequently, NHEJ deficiency confers (severe) combined immunodeficiency - (S)CID - due to a failure to carry out V(D)J recombination efficiently. NHEJ also functions in class switch recombination, another step enhancing T and B cell diversity. Prompted by these findings, a search for radiosensitivity amongst (S)CID patients revealed a radiosensitive sub-class, defined as RS-SCID. Mutations in NHEJ genes, defining human syndromes deficient in DNA ligase IV (LIG4 Syndrome), XLF-Cernunnos, Artemis or DNA-PKcs, have been identified in such patients. Mutations in XRCC4 or Ku70,80 in patients have not been identified. RS-SCID patients frequently display additional characteristics including microcephaly, dysmorphic facial features and growth delay. Here, we overview the clinical spectrum of RS-SCID patients and discuss our current understanding of the underlying biology.
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Affiliation(s)
- Lisa Woodbine
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Andrew R Gennery
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Penny A Jeggo
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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Curtin NJ. Inhibiting the DNA damage response as a therapeutic manoeuvre in cancer. Br J Pharmacol 2014; 169:1745-65. [PMID: 23682925 DOI: 10.1111/bph.12244] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED The DNA damage response (DDR), consisting of an orchestrated network of proteins effecting repair and signalling to cell cycle arrest, to allow time to repair, is essential for cell viability and to prevent DNA damage being passed on to daughter cells. The DDR is dysregulated in cancer with some pathways up-regulated and others down-regulated or lost. Up-regulated pathways can confer resistance to anti-cancer DNA damaging agents. Therefore, inhibitors of key components of these pathways have the potential to prevent this therapeutic resistance. Conversely, defects in a particular DDR pathway may lead to dependence on a complementary pathway. Inhibition of this complementary pathway may result in tumour-specific cell killing. Thus, inhibitors of the DDR have the potential to increase the efficacy of DNA damaging chemotherapy and radiotherapy and have single-agent activity against tumours with a specific DDR defect. This review describes the compounds that have been designed to inhibit specific DDR targets and summarizes the pre-clinical and clinical evaluation of these inhibitors of DNA damage signalling and repair. LINKED ARTICLES This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.
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Affiliation(s)
- N J Curtin
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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Zhou Y, Paull TT. DNA-dependent protein kinase regulates DNA end resection in concert with Mre11-Rad50-Nbs1 (MRN) and ataxia telangiectasia-mutated (ATM). J Biol Chem 2013; 288:37112-25. [PMID: 24220101 PMCID: PMC3873567 DOI: 10.1074/jbc.m113.514398] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 11/07/2013] [Indexed: 11/06/2022] Open
Abstract
The resection of DNA double strand breaks initiates homologous recombination (HR) and is critical for genomic stability. Using direct measurement of resection in human cells and reconstituted assays of resection with purified proteins in vitro, we show that DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a classic nonhomologous end joining factor, antagonizes double strand break resection by blocking the recruitment of resection enzymes such as exonuclease 1 (Exo1). Autophosphorylation of DNA-PKcs promotes DNA-PKcs dissociation and consequently Exo1 binding. Ataxia telangiectasia-mutated kinase activity can compensate for DNA-PKcs autophosphorylation and promote resection under conditions where DNA-PKcs catalytic activity is inhibited. The Mre11-Rad50-Nbs1 (MRN) complex further stimulates resection in the presence of Ku and DNA-PKcs by recruiting Exo1 and enhancing DNA-PKcs autophosphorylation, and it also inhibits DNA ligase IV/XRCC4-mediated end rejoining. This work suggests that, in addition to its key role in nonhomologous end joining, DNA-PKcs also acts in concert with MRN and ataxia telangiectasia-mutated to regulate resection and thus DNA repair pathway choice.
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Affiliation(s)
- Yi Zhou
- From the Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
| | - Tanya T. Paull
- From the Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
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Zhou Y, Caron P, Legube G, Paull TT. Quantitation of DNA double-strand break resection intermediates in human cells. Nucleic Acids Res 2013; 42:e19. [PMID: 24362840 PMCID: PMC3919611 DOI: 10.1093/nar/gkt1309] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
5′ strand resection at DNA double strand breaks (DSBs) is critical for homologous recombination (HR) and genomic stability. Here we develop a novel method to quantitatively measure single-stranded DNA intermediates in human cells and find that the 5′ strand at endonuclease-generated break sites is resected up to 3.5 kb in a cell cycle–dependent manner. Depletion of CtIP, Mre11, Exo1 or SOSS1 blocks resection, while depletion of 53BP1, Ku or DNA-dependent protein kinase catalytic subunit leads to increased resection as measured by this method. While 53BP1 negatively regulates DNA end processing, depletion of Brca1 does not, suggesting that the role of Brca1 in HR is primarily to promote Rad51 filament formation, not to regulate end resection.
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Affiliation(s)
- Yi Zhou
- The Department of Molecular Biosciences, The Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA, Université de Toulouse, UPS, LBCMCP, 31062 Toulouse, France and CNRS, LBCMCP, F-31062 Toulouse, France
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40
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Abdisalaam S, Davis AJ, Chen DJ, Alexandrakis G. Scanning fluorescence correlation spectroscopy techniques to quantify the kinetics of DNA double strand break repair proteins after γ-irradiation and bleomycin treatment. Nucleic Acids Res 2013; 42:e5. [PMID: 24137007 PMCID: PMC3874206 DOI: 10.1093/nar/gkt908] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A common feature of DNA repair proteins is their mobilization in response to DNA damage. The ability to visualizing and quantifying the kinetics of proteins localizing/dissociating from DNA double strand breaks (DSBs) via immunofluorescence or live cell fluorescence microscopy have been powerful tools in allowing insight into the DNA damage response, but these tools have some limitations. For example, a number of well-established DSB repair factors, in particular those required for non-homologous end joining (NHEJ), do not form discrete foci in response to DSBs induced by ionizing radiation (IR) or radiomimetic drugs, including bleomycin, in living cells. In this report, we show that time-dependent kinetics of the NHEJ factors Ku80 and DNA-dependent protein kinase catalytic subunits (DNA-PKcs) in response to IR and bleomycin can be quantified by Number and Brightness analysis and Raster-scan Image Correlation Spectroscopy. Fluorescent-tagged Ku80 and DNA-PKcs quickly mobilized in response to IR and bleomycin treatments consistent with prior reports using laser-generated DSBs. The response was linearly dependent on IR dose, and blocking NHEJ enhanced immobilization of both Ku80 and DNA-PKcs after DNA damage. These findings support the idea of using Number and Brightness and Raster-scan Image Correlation Spectroscopy as methods to monitor kinetics of DSB repair proteins in living cells under conditions mimicking radiation and chemotherapy treatments.
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Affiliation(s)
- Salim Abdisalaam
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Boulevard, Arlington, TX 76010-0138, USA and Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9187, USA
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41
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Shimada M, Nakanishi M. Response to DNA damage: why do we need to focus on protein phosphatases? Front Oncol 2013; 3:8. [PMID: 23386996 PMCID: PMC3560363 DOI: 10.3389/fonc.2013.00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/09/2013] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic cells are continuously threatened by unavoidable errors during normal DNA replication or various sources of genotoxic stresses that cause DNA damage or stalled replication. To maintain genomic integrity, cells have developed a coordinated signaling network, known as the DNA damage response (DDR). Following DNA damage, sensor molecules detect the presence of DNA damage and transmit signals to downstream transducer molecules. This in turn conveys the signals to numerous effectors, which initiate a large number of specific biological responses, including transient cell cycle arrest mediated by checkpoints, DNA repair, and apoptosis. It is recently becoming clear that dephosphorylation events are involved in keeping DDR factors inactive during normal cell growth. Moreover, dephosphorylation is required to shut off checkpoint arrest following DNA damage and has been implicated in the activation of the DDR. Spatial and temporal regulation of phosphorylation events is essential for the DDR, and fine-tuning of phosphorylation is partly mediated by protein phosphatases. While the role of kinases in the DDR has been well documented, the complex roles of protein dephosphorylation have only recently begun to be investigated. Therefore, it is important to focus on the role of phosphatases and to determine how their activity is regulated upon DNA damage. In this work, we summarize current knowledge on the involvement of serine/threonine phosphatases, especially the protein phosphatase 1, protein phosphatase 2A, and protein phosphatase Mg2+/Mn2+-dependent families, in the DDR.
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Affiliation(s)
- Midori Shimada
- Department of Cell Biology, Graduate School of Medical Sciences, Nagoya City University Nagoya, Japan
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42
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Davis AJ, Lee KJ, Chen DJ. The N-terminal region of the DNA-dependent protein kinase catalytic subunit is required for its DNA double-stranded break-mediated activation. J Biol Chem 2013; 288:7037-46. [PMID: 23322783 DOI: 10.1074/jbc.m112.434498] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) plays an essential role in the repair of DNA double-stranded breaks (DSBs) mediated by the nonhomologous end-joining pathway. DNA-PK is a holoenzyme consisting of a DNA-binding (Ku70/Ku80) and catalytic (DNA-PKcs) subunit. DNA-PKcs is a serine/threonine protein kinase that is recruited to DSBs via Ku70/80 and is activated once the kinase is bound to the DSB ends. In this study, two large, distinct fragments of DNA-PKcs, consisting of the N terminus (amino acids 1-2713), termed N-PKcs, and the C terminus (amino acids 2714-4128), termed C-PKcs, were produced to determine the role of each terminal region in regulating the activity of DNA-PKcs. N-PKcs but not C-PKcs interacts with the Ku-DNA complex and is required for the ability of DNA-PKcs to localize to DSBs. C-PKcs has increased basal kinase activity compared with DNA-PKcs, suggesting that the N-terminal region of DNA-PKcs keeps basal activity low. The kinase activity of C-PKcs is not stimulated by Ku70/80 and DNA, further supporting that the N-terminal region is required for binding to the Ku-DNA complex and full activation of kinase activity. Collectively, the results show the N-terminal region mediates the interaction between DNA-PKcs and the Ku-DNA complex and is required for its DSB-induced enzymatic activity.
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Affiliation(s)
- Anthony J Davis
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Wei F, Yan J, Tang D, Lin X, He L, Xie Y, Tao L, Wang S. Inhibition of ERK activation enhances the repair of double-stranded breaks via non-homologous end joining by increasing DNA-PKcs activation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:90-100. [PMID: 23098854 DOI: 10.1016/j.bbamcr.2012.10.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 10/02/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
Non-homologous end joining (NHEJ) is one of the major pathways that repairs double-stranded DNA breaks (DSBs). Activation of DNA-PK is required for NHEJ. However, the mechanism leading to DNA-PKcs activation remains incompletely understood. We provide evidence here that the MEK-ERK pathway plays a role in DNA-PKcs-mediated NHEJ. In comparison to the vehicle control (DMSO), etoposide (ETOP)-induced DSBs in MCF7 cells were more rapidly repaired in the presence of U0126, a specific MEK inhibitor, based on the reduction of γH2AX and tail moments. Additionally, U0126 increased reactivation of luciferase activity, which resulted from the repair of restriction enzyme-cleaved DSBs. Furthermore, while inhibition of ERK activation using the dominant-negative MEK1K97M accelerated the repair of DSBs, enforcing ERK activation with the constitutively active MEK1Q56P reduced DSB repair. In line with MEK activating ERK1 and ERK2 kinases, knockdown of either ERK1 or ERK2 increased DSB repair. Consistent with the activation of DNA-PKcs being required for NHEJ, we demonstrated that inhibition of ERK activation using U0126, MEK1K97M, and knockdown of ERK1 or ERK2 enhanced ETOP-induced activation of DNA-PKcs. Conversely, enforcing ERK activation by MEK1Q56P reduced ETOP-initiated DNA-PKcs activation. Taken together, we demonstrate that ERK reduces NHEJ-mediated repair of DSBs via attenuation of DNA-PKcs activation.
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Affiliation(s)
- Fengxiang Wei
- The Genetics Laboratory, Maternity and Child Healthcare Hospital, Shenzhen, Guangdong, People's Republic of China.
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Runkle EA, Zhang H, Cai Z, Zhu Z, Karger BL, Wu SL, O'Rourke DM, Zhou Z, Wang Q, Greene MI. Reversion of the ErbB malignant phenotype and the DNA damage response. Exp Mol Pathol 2012; 93:324-33. [PMID: 23022358 DOI: 10.1016/j.yexmp.2012.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 12/18/2022]
Abstract
The ErbB or HER family is a group of membrane bound tyrosine kinase receptors that initiate signal transduction cascades, which are critical to a wide range of biological processes. When over-expressed or mutated, members of this kinase family form homomeric or heteromeric kinase assemblies that are involved in certain human malignancies. Targeted therapy evolved from studies showing that monoclonal antibodies to the ectodomain of ErbB2/neu would reverse the malignant phenotype. Unfortunately, tumors develop resistance to targeted therapies even when coupled with genotoxic insults such as radiation. Radiation treatment predominantly induces double strand DNA breaks, which, if not repaired, are potentially lethal to the cell. Some tumors are resistant to radiation treatment because they effectively repair double strand breaks. We and others have shown that even in the presence of ionizing radiation, active ErbB kinase signaling apparently enhances the repair process, such that transformed cells resist genotoxic signal induced cell death. We review here the current understanding of ErbB signaling and DNA double strand break repair. Some studies have identified a mechanism by which DNA damage is coordinated to assemblies of proteins that associate with SUN domain containing proteins. These assemblies represent a new target for therapy of resistant tumor cells.
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Affiliation(s)
- E Aaron Runkle
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Martín M, Terradas M, Tusell L, Genescà A. ATM and DNA-PKcs make a complementary couple in DNA double strand break repair. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2012; 751:29-35. [DOI: 10.1016/j.mrrev.2011.12.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 01/21/2023]
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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Increased Artemis levels confer radioresistance to both high and low LET radiation exposures. Radiat Oncol 2012; 7:96. [PMID: 22713703 PMCID: PMC3585927 DOI: 10.1186/1748-717x-7-96] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 05/18/2012] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Artemis has a defined role in V(D)J recombination and has been implicated in the repair of radiation induced double-strand breaks. However the exact function(s) of Artemis in DNA repair and its preferred substrate(s) in vivo remain undefined. Our previous work suggests that Artemis is important for the repair of complex DNA damage like that inflicted by high Linear Energy Transfer (LET) radiation. To establish the contribution of Artemis in repairing DNA damage caused by various radiation qualities, we evaluated the effect of over-expressing Artemis on cell survival, DNA repair, and cell cycle arrest after exposure to high and low LET radiation. RESULTS Our data reveal that Artemis over-expression confers marked radioprotection against both types of radiation, although the radioprotective effect was greater following high LET radiation. Inhibitor studies reveal that the radioprotection imparted by Artemis is primarily dependent on DNA-PK activity, and to a lesser extent on ATM kinase activity. Together, these data suggest a DNA-PK dependent role for Artemis in the repair of complex DNA damage. CONCLUSIONS These findings indicate that Artemis levels significantly influence radiation toxicity in human cells and suggest that Artemis inhibition could be a practical target for adjuvant cancer therapies.
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Olsen BB, Wang SY, Svenstrup TH, Chen BPC, Guerra B. Protein kinase CK2 localizes to sites of DNA double-strand break regulating the cellular response to DNA damage. BMC Mol Biol 2012; 13:7. [PMID: 22404984 PMCID: PMC3316135 DOI: 10.1186/1471-2199-13-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/09/2012] [Indexed: 02/02/2023] Open
Abstract
Background The DNA-dependent protein kinase (DNA-PK) is a nuclear complex composed of a large catalytic subunit (DNA-PKcs) and a heterodimeric DNA-targeting subunit Ku. DNA-PK is a major component of the non-homologous end-joining (NHEJ) repair mechanism, which is activated in the presence of DNA double-strand breaks induced by ionizing radiation, reactive oxygen species and radiomimetic drugs. We have recently reported that down-regulation of protein kinase CK2 by siRNA interference results in enhanced cell death specifically in DNA-PKcs-proficient human glioblastoma cells, and this event is accompanied by decreased autophosphorylation of DNA-PKcs at S2056 and delayed repair of DNA double-strand breaks. Results In the present study, we show that CK2 co-localizes with phosphorylated histone H2AX to sites of DNA damage and while CK2 gene knockdown is associated with delayed DNA damage repair, its overexpression accelerates this process. We report for the first time evidence that lack of CK2 destabilizes the interaction of DNA-PKcs with DNA and with Ku80 at sites of genetic lesions. Furthermore, we show that CK2 regulates the phosphorylation levels of DNA-PKcs only in response to direct induction of DNA double-strand breaks. Conclusions Taken together, these results strongly indicate that CK2 plays a prominent role in NHEJ by facilitating and/or stabilizing the binding of DNA-PKcs and, possibly other repair proteins, to the DNA ends contributing to efficient DNA damage repair in mammalian cells.
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Affiliation(s)
- Birgitte B Olsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Hosing AS, Valerie NCK, Dziegielewski J, Brautigan DL, Larner JM. PP6 regulatory subunit R1 is bidentate anchor for targeting protein phosphatase-6 to DNA-dependent protein kinase. J Biol Chem 2012; 287:9230-9. [PMID: 22298787 DOI: 10.1074/jbc.m111.333708] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA-dependent protein kinase (DNA-PK) becomes activated in response to DNA double strand breaks, initiating repair by the non-homologous end joining pathway. DNA·PK complexes with the regulatory subunit SAPSR1 (R1) of protein phosphatase-6 (PP6). Knockdown of either R1 or PP6c prevents DNA-PK activation in response to ionizing radiation-induced DNA damage and radiosensitizes glioblastoma cells. Here, we demonstrate that R1 is necessary for and bridges the interaction between DNA-PK and PP6c. Using R1 deletion mutants, DNA-PK binding was mapped to two distinct regions of R1 spanning residues 1-326 and 522-700. Either region expressed alone was sufficient to bind DNA-PK, but only deletion of residues 1-326, not 522-700, eliminated interaction of R1 with DNA-PK. We assign 1-326 as the dominant domain and 522-700 as the supporting region. These results demonstrate that R1 acts as a bidentate anchor to DNA-PK and recruits PP6c. Targeting the dominant interface with small molecule or peptidomimetic inhibitors could specifically prevent activation of DNA-PK and thereby sensitize cells to ionizing radiation and other genotoxic agents.
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Affiliation(s)
- Amol S Hosing
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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Abstract
Developing lymphocytes must assemble antigen receptor genes encoding the B cell and T cell receptors. This process is executed by the V(D)J recombination reaction, which can be divided into DNA cleavage and DNA joining steps. The former is carried out by a lymphocyte-specific RAG endonuclease, which mediates DNA cleavage at two recombining gene segments and their flanking RAG recognition sequences. RAG cleavage generates four broken DNA ends that are repaired by nonhomologous end joining forming coding and signal joints. On rare occasions, these DNA ends may join aberrantly forming chromosomal lesions such as translocations, deletions and inversions that have the potential to cause cellular transformation and lymphoid tumors. We discuss the activation of DNA damage responses by RAG-induced DSBs focusing on the component pathways that promote their normal repair and guard against their aberrant resolution. Moreover, we discuss how this DNA damage response impacts processes important for lymphocyte development.
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Affiliation(s)
- Beth A Helmink
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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