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Ng YB, Akincilar SC. Shaping DNA damage responses: Therapeutic potential of targeting telomeric proteins and DNA repair factors in cancer. Curr Opin Pharmacol 2024; 76:102460. [PMID: 38776747 DOI: 10.1016/j.coph.2024.102460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 05/25/2024]
Abstract
Shelterin proteins regulate genomic stability by preventing inappropriate DNA damage responses (DDRs) at telomeres. Unprotected telomeres lead to persistent DDR causing cell cycle inhibition, growth arrest, and apoptosis. Cancer cells rely on DDR to protect themselves from DNA lesions and exogenous DNA-damaging agents such as chemotherapy and radiotherapy. Therefore, targeting DDR machinery is a promising strategy to increase the sensitivity of cancer cells to existing cancer therapies. However, the success of these DDR inhibitors depends on other mutations, and over time, patients develop resistance to these therapies. This suggests the need for alternative approaches. One promising strategy is co-inhibiting shelterin proteins with DDR molecules, which would offset cellular fitness in DNA repair in a mutation-independent manner. This review highlights the associations and dependencies of the shelterin complex with the DDR proteins and discusses potential co-inhibition strategies that might improve the therapeutic potential of current inhibitors.
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Affiliation(s)
- Yu Bin Ng
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
| | - Semih Can Akincilar
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore.
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2
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Sonmez C, Toia B, Eickhoff P, Matei AM, El Beyrouthy M, Wallner B, Douglas ME, de Lange T, Lottersberger F. DNA-PK controls Apollo's access to leading-end telomeres. Nucleic Acids Res 2024; 52:4313-4327. [PMID: 38407308 PMCID: PMC11077071 DOI: 10.1093/nar/gkae105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 01/23/2024] [Accepted: 02/01/2024] [Indexed: 02/27/2024] Open
Abstract
The complex formed by Ku70/80 and DNA-PKcs (DNA-PK) promotes the synapsis and the joining of double strand breaks (DSBs) during canonical non-homologous end joining (c-NHEJ). In c-NHEJ during V(D)J recombination, DNA-PK promotes the processing of the ends and the opening of the DNA hairpins by recruiting and/or activating the nuclease Artemis/DCLRE1C/SNM1C. Paradoxically, DNA-PK is also required to prevent the fusions of newly replicated leading-end telomeres. Here, we describe the role for DNA-PK in controlling Apollo/DCLRE1B/SNM1B, the nuclease that resects leading-end telomeres. We show that the telomeric function of Apollo requires DNA-PKcs's kinase activity and the binding of Apollo to DNA-PK. Furthermore, AlphaFold-Multimer predicts that Apollo's nuclease domain has extensive additional interactions with DNA-PKcs, and comparison to the cryo-EM structure of Artemis bound to DNA-PK phosphorylated on the ABCDE/Thr2609 cluster suggests that DNA-PK can similarly grant Apollo access to the DNA end. In agreement, the telomeric function of DNA-PK requires the ABCDE/Thr2609 cluster. These data reveal that resection of leading-end telomeres is regulated by DNA-PK through its binding to Apollo and its (auto)phosphorylation-dependent positioning of Apollo at the DNA end, analogous but not identical to DNA-PK dependent regulation of Artemis at hairpins.
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Affiliation(s)
- Ceylan Sonmez
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Patrik Eickhoff
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Andreea Medeea Matei
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Michael El Beyrouthy
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Björn Wallner
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 58 183, Sweden
| | - Max E Douglas
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, NY, NY 10021, USA
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
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3
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Zhou H, Khan D, Hussain SM, Gerdes N, Hagenbeck C, Rana M, Cornelius JF, Muhammad S. Colchicine prevents oxidative stress-induced endothelial cell senescence via blocking NF-κB and MAPKs: implications in vascular diseases. J Inflamm (Lond) 2023; 20:41. [PMID: 38001470 PMCID: PMC10675905 DOI: 10.1186/s12950-023-00366-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
BACKGROUND Smoking, alcohol abuse, and hypertension are - among others, potential risk factors for cardiovascular diseases. These risk factors generate oxidative stress and cause oxidative stress-induced DNA damage, resulting in cellular senescence and senescence-associated secretory phenotype (SASP). The SASP factors in feed-forward response exacerbate inflammation and cause tissue remodeling, resulting in atherosclerotic plaque formation and rupture. RESULTS Colchicine inhibited ROS generation and mitigated oxidative stress-induced DNA damage. It dampened oxidative stress-induced endothelial cell senescence and improved the expression of DNA repair protein KU80 and aging marker Lamin B1. The drug attenuated the expression of senescence marker P21 at mRNA and protein levels. The pathway analysis showed that colchicine inhibited NF-κB and MAPKs pathways and subdued mTOR activation. Colchicine also attenuated mRNA expression of interleukin (IL)-1β, IL-6, IL-8, MCP-1, ICAM-1, and E-selectin. Furthermore, colchicine reduced the mRNA and protein expression of matrix metalloproteinase (MMP-2). CONCLUSION In summary, colchicine blocked oxidative stress-induced senescence and SASP by inhibiting the activation of NF-κB and MAPKs pathways.
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Affiliation(s)
- Huakang Zhou
- Department of Neurosurgery, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine- Universität Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Dilaware Khan
- Department of Neurosurgery, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine- Universität Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany.
| | - Sajid Muhammad Hussain
- Cologne Center for Genomics (CCG), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
| | - Norbert Gerdes
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty and University Hospital, Heinrich-Heine-University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
- Cardiovascular Reasearch Institute Düsseldorf (CARID), Medical Faculty, Heinrich-Heine- University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Carsten Hagenbeck
- Clinic for Gynecology and Obstetrics, Medical Faculty, Heinrich-Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Majeed Rana
- Department of Oral-, Maxillofacial and Facial Plastic Surgery, University Hospital Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Jan Frederick Cornelius
- Department of Neurosurgery, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine- Universität Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Sajjad Muhammad
- Department of Neurosurgery, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine- Universität Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
- Department of Neurosurgery, University Hospital Helsinki, Topeliuksenkatu 5, Helsinki, 00260, Finland
- Department of Neurosurgery, King Edward Medical University, Lahore, Pakistan
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4
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Myler LR, Toia B, Vaughan CK, Takai K, Matei AM, Wu P, Paull TT, de Lange T, Lottersberger F. DNA-PK and the TRF2 iDDR inhibit MRN-initiated resection at leading-end telomeres. Nat Struct Mol Biol 2023; 30:1346-1356. [PMID: 37653239 PMCID: PMC10497418 DOI: 10.1038/s41594-023-01072-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 07/18/2023] [Indexed: 09/02/2023]
Abstract
Telomeres replicated by leading-strand synthesis lack the 3' overhang required for telomere protection. Surprisingly, resection of these blunt telomeres is initiated by the telomere-specific 5' exonuclease Apollo rather than the Mre11-Rad50-Nbs1 (MRN) complex, the nuclease that acts at DNA breaks. Without Apollo, leading-end telomeres undergo fusion, which, as demonstrated here, is mediated by alternative end joining. Here, we show that DNA-PK and TRF2 coordinate the repression of MRN at blunt mouse telomeres. DNA-PK represses an MRN-dependent long-range resection, while the endonuclease activity of MRN-CtIP, which could cleave DNA-PK off of blunt telomere ends, is inhibited in vitro and in vivo by the iDDR of TRF2. AlphaFold-Multimer predicts a conserved association of the iDDR with Rad50, potentially interfering with CtIP binding and MRN endonuclease activation. We propose that repression of MRN-mediated resection is a conserved aspect of telomere maintenance and represents an ancient feature of DNA-PK and the iDDR.
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Affiliation(s)
- Logan R Myler
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Cara K Vaughan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Kaori Takai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Andreea M Matei
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Peng Wu
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA.
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden.
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5
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Kelly RD, Parmar G, Bayat L, Maitland MER, Lajoie GA, Edgell DR, Schild-Poulter C. Noncanonical functions of Ku may underlie essentiality in human cells. Sci Rep 2023; 13:12162. [PMID: 37500706 PMCID: PMC10374653 DOI: 10.1038/s41598-023-39166-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/20/2023] [Indexed: 07/29/2023] Open
Abstract
The Ku70/80 heterodimer is a key player in non-homologous end-joining DNA repair but is involved in other cellular functions like telomere regulation and maintenance, in which Ku's role is not fully characterized. It was previously reported that knockout of Ku80 in a human cell line results in lethality, but the underlying cause of Ku essentiality in human cells has yet to be fully explored. Here, we established conditional Ku70 knockout cells using CRISPR/Cas9 editing to study the essentiality of Ku70 function. While we observed loss of cell viability upon Ku depletion, we did not detect significant changes in telomere length, nor did we record lethal levels of DNA damage upon loss of Ku. Analysis of global proteome changes following Ku70 depletion revealed dysregulations of several cellular pathways including cell cycle/mitosis, RNA related processes, and translation/ribosome biogenesis. Our study suggests that the driving cause of loss of cell viability in Ku70 knockouts is not linked to the functions of Ku in DNA repair or at telomeres. Moreover, our data shows that loss of Ku affects multiple cellular processes and pathways and suggests that Ku plays critical roles in cellular processes beyond DNA repair and telomere maintenance to maintain cell viability.
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Affiliation(s)
- Rachel D Kelly
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Gursimran Parmar
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Laila Bayat
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Matthew E R Maitland
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Gilles A Lajoie
- Department of Biochemistry, Western University, London, ON, Canada
| | - David R Edgell
- Department of Biochemistry, Western University, London, ON, Canada
| | - Caroline Schild-Poulter
- Department of Biochemistry, Western University, London, ON, Canada.
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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6
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Zhou H, Khan D, Gerdes N, Hagenbeck C, Rana M, Cornelius JF, Muhammad S. Colchicine Protects against Ethanol-Induced Senescence and Senescence-Associated Secretory Phenotype in Endothelial Cells. Antioxidants (Basel) 2023; 12:antiox12040960. [PMID: 37107335 PMCID: PMC10135532 DOI: 10.3390/antiox12040960] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/11/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
Inflammaging is a potential risk factor for cardiovascular diseases. It results in the development of thrombosis and atherosclerosis. The accumulation of senescent cells in vessels causes vascular inflammaging and contributes to plaque formation and rupture. In addition to being an acquired risk factor for cardiovascular diseases, ethanol can induce inflammation and senescence, both of which have been implicated in cardiovascular diseases. In the current study, we used colchicine to abate the cellular damaging effects of ethanol on endothelial cells. Colchicine prevented senescence and averted oxidative stress in endothelial cells exposed to ethanol. It lowered the relative protein expression of aging and senescence marker P21 and restored expression of the DNA repair proteins KU70/KU80. Colchicine inhibited the activation of nuclear factor kappa B (NFκ-B) and mitogen activated protein kinases (MAPKs) in ethanol-treated endothelial cells. It reduced ethanol-induced senescence-associated secretory phenotype. In summary, we show that colchicine ameliorated the ethanol-caused molecular events, resulting in attenuated senescence and senescence-associated secretory phenotype in endothelial cells.
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Affiliation(s)
- Huakang Zhou
- Department of Neurosurgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Dilaware Khan
- Department of Neurosurgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Norbert Gerdes
- Division of Cardiology, Pulmonology and Vascular Medicine, University Hospital and Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Carsten Hagenbeck
- Clinic for Gynecology and Obstetrics, University Clinic, 40225 Düsseldorf, Germany
| | - Majeed Rana
- Department of Oral, Maxillofacial and Facial Plastic Surgery, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Jan Frederick Cornelius
- Department of Neurosurgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Sajjad Muhammad
- Department of Neurosurgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
- Department of Neurosurgery, University Hospital Helsinki, Topeliuksenkatu 5, 00260 Helsinki, Finland
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7
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Mendoza-Munoz PL, Gavande NS, VanderVere-Carozza PS, Pawelczak K, Dynlacht J, Garrett J, Turchi J. Ku-DNA binding inhibitors modulate the DNA damage response in response to DNA double-strand breaks. NAR Cancer 2023; 5:zcad003. [PMID: 36755959 PMCID: PMC9900423 DOI: 10.1093/narcan/zcad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/09/2022] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
The DNA-dependent protein kinase (DNA-PK) plays a critical role in the DNA damage response (DDR) and non-homologous end joining (NHEJ) double-strand break (DSB) repair pathways. Consequently, DNA-PK is a validated therapeutic target for cancer treatment in certain DNA repair-deficient cancers and in combination with ionizing radiation (IR). We have previously reported the discovery and development of a novel class of DNA-PK inhibitors with a unique mechanism of action, blocking the Ku 70/80 heterodimer interaction with DNA. These Ku-DNA binding inhibitors (Ku-DBi's) display nanomolar activity in vitro, inhibit cellular DNA-PK, NHEJ-catalyzed DSB repair and sensitize non-small cell lung cancer (NSCLC) cells to DSB-inducing agents. In this study, we demonstrate that chemical inhibition of the Ku-DNA interaction potentiates the cellular effects of bleomycin and IR via p53 phosphorylation through the activation of the ATM pathway. This response is concomitant with a reduction of DNA-PK catalytic subunit (DNA-PKcs) autophosphorylation at S2056 and a time-dependent increase in H2AX phosphorylation at S139. These results are consistent with Ku-DBi's abrogating DNA-PKcs autophosphorylation to impact DSB repair and DDR signaling through a novel mechanism of action, and thus represent a promising anticancer therapeutic strategy in combination with DNA DSB-inducing agents.
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Affiliation(s)
- Pamela L Mendoza-Munoz
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Navnath S Gavande
- Department of Pharmaceutical Sciences, Wayne State University College of Pharmacy and Health Sciences, Detroit, MI 48201-2417, USA
- Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201-2417, USA
| | | | | | - Joseph R Dynlacht
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Joy E Garrett
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - John J Turchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- NERx Biosciences. Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University, School of Medicine, Indianapolis, IN 46202, USA
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8
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Dutta B, Osato M. The RUNX Family, a Novel Multifaceted Guardian of the Genome. Cells 2023; 12:255. [PMID: 36672189 PMCID: PMC9856552 DOI: 10.3390/cells12020255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/24/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023] Open
Abstract
The DNA repair machinery exists to protect cells from daily genetic insults by orchestrating multiple intrinsic and extrinsic factors. One such factor recently identified is the Runt-related transcription factor (RUNX) family, a group of proteins that act as a master transcriptional regulator for multiple biological functions such as embryonic development, stem cell behaviors, and oncogenesis. A significant number of studies in the past decades have delineated the involvement of RUNX proteins in DNA repair. Alterations in RUNX genes cause organ failure and predisposition to cancers, as seen in patients carrying mutations in the other well-established DNA repair genes. Herein, we review the currently existing findings and provide new insights into transcriptional and non-transcriptional multifaceted regulation of DNA repair by RUNX family proteins.
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Affiliation(s)
- Bibek Dutta
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Motomi Osato
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan
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9
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Li X, Khan D, Rana M, Hänggi D, Muhammad S. Doxycycline Attenuated Ethanol-Induced Inflammaging in Endothelial Cells: Implications in Alcohol-Mediated Vascular Diseases. Antioxidants (Basel) 2022; 11:antiox11122413. [PMID: 36552622 PMCID: PMC9774758 DOI: 10.3390/antiox11122413] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Excess alcohol consumption is a potential risk factor for cardiovascular diseases and is linked to accelerated aging. Drug discovery to reduce toxic cellular events of alcohol is required. Here, we investigated the effects of ethanol on human umbilical vein endothelial cells (HUVECs) and explored if doxycycline attenuates ethanol-mediated molecular events in endothelial cells. Initially, a drug screening using a panel of 170 drugs was performed, and doxycycline was selected for further experiments. HUVECs were treated with different concentrations (300 mM and 400 mM) of ethanol with or without doxycycline (10 µg/mL). Telomere length was quantified as telomere to single-copy gene (T/S) ratio. Telomere length and the mRNA expression were quantified by qRT-PCR, and protein level was analyzed by Western blot (WB). Ethanol treatment accelerated cellular aging, and doxycycline treatment recovered telomere length. Pathway analysis showed that doxycycline inhibited mTOR and NFκ-B activation. Doxycycline restored the expression of aging-associated proteins, including lamin b1 and DNA repair proteins KU70 and KU80. Doxycycline reduced senescence and senescence-associated secretory phenotype (SASP) in ethanol-treated HUVECs. In conclusion, we report that ethanol-induced inflammation and aging in HUVECs were ameliorated by doxycycline.
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Affiliation(s)
- Xuanchen Li
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Dilaware Khan
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
- Correspondence: ; Tel.: +49-21181-08782
| | - Majeed Rana
- Department of Oral and Maxillofacial Surgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Daniel Hänggi
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Sajjad Muhammad
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
- Department of Neurosurgery, University Hospital Helsinki, Topeliuksenkatu 5, 00260 Helsinki, Finland
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10
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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11
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Low GKM, Ting APL, Fok EDZ, Gopalakrishnan K, Zeegers D, Khaw AK, Jayapal M, Martinez-Lopez W, Hande MP. Role of Xeroderma pigmentosum D (XPD) protein in genome maintenance in human cells under oxidative stress. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 876-877:503444. [PMID: 35483790 DOI: 10.1016/j.mrgentox.2022.503444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/29/2021] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
Xeroderma pigmentosum D (XPD) protein plays a pivotal role in the nucleotide excision repair pathway. XPD unwinds the local area of the damaged DNA by virtue of constituting transcription factor II H (TFIIH) and is important not only for repair but also for basal transcription. Although cells deficient in XPD have shown to be defective in oxidative base-lesion repair, the effects of the oxidative assault on primary fibroblasts from patients suffering from Xeroderma Pigmentosum D have not been fully explored. Therefore, we sought to investigate the role of XPD in oxidative DNA damage-repair by treating primary fibroblasts derived from a patient suffering from Xeroderma Pigmentosum D, with hydrogen peroxide. Our results show dose-dependent increase in genotoxicity with minimal effect on cytotoxicity with H2O2 in XPD deficient cells compared to control cells. XPD deficient cells displayed increased susceptibility and reduced repair capacity when subjected to DNA damage induced by oxidative stress. XPD deficient fibroblasts exhibited increased telomeric loss after H2O2 treatment. In addition, we demonstrated that chronic oxidative stress induced accelerated premature senescence characteristics. Gene expression profiling revealed alterations in genes involved in transcription and nucleotide metabolisms, as well as in cellular and cell cycle processes in a more significant way than in other pathways. This study highlights the role of XPD in the repair of oxidative stress and telomere maintenance. Lack of functional XPD seems to increase the susceptibility of oxidative stress-induced genotoxicity while retaining cell viability posing as a potential cancer risk factor of Xeroderma Pigmentosum D patients.
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Affiliation(s)
- Grace Kah Mun Low
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Aloysius Poh Leong Ting
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Edwin Dan Zhihao Fok
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kalpana Gopalakrishnan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Dimphy Zeegers
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Aik Kia Khaw
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Manikandan Jayapal
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wilner Martinez-Lopez
- Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay; Associate Unit on Genomic Stability, Faculty of Medicine, University of the Republic (UdelaR), Montevideo, Uruguay; Vellore Institute of Technology, Vellore, India
| | - M Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Vellore Institute of Technology, Vellore, India; Mangalore University, India.
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12
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Linke R, Limmer M, Juranek SA, Heine A, Paeschke K. The Relevance of G-Quadruplexes for DNA Repair. Int J Mol Sci 2021; 22:12599. [PMID: 34830478 PMCID: PMC8620898 DOI: 10.3390/ijms222212599] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 01/28/2023] Open
Abstract
DNA molecules can adopt a variety of alternative structures. Among these structures are G-quadruplex DNA structures (G4s), which support cellular function by affecting transcription, translation, and telomere maintenance. These structures can also induce genome instability by stalling replication, increasing DNA damage, and recombination events. G-quadruplex-driven genome instability is connected to tumorigenesis and other genetic disorders. In recent years, the connection between genome stability, DNA repair and G4 formation was further underlined by the identification of multiple DNA repair proteins and ligands which bind and stabilize said G4 structures to block specific DNA repair pathways. The relevance of G4s for different DNA repair pathways is complex and depends on the repair pathway itself. G4 structures can induce DNA damage and block efficient DNA repair, but they can also support the activity and function of certain repair pathways. In this review, we highlight the roles and consequences of G4 DNA structures for DNA repair initiation, processing, and the efficiency of various DNA repair pathways.
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Affiliation(s)
- Rebecca Linke
- Department of Oncology, Hematology, Rheumatology and Immune-Oncology, University Hospital Bonn, 53127 Bonn, Germany; (R.L.); (M.L.); (S.A.J.); (A.H.)
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michaela Limmer
- Department of Oncology, Hematology, Rheumatology and Immune-Oncology, University Hospital Bonn, 53127 Bonn, Germany; (R.L.); (M.L.); (S.A.J.); (A.H.)
| | - Stefan A. Juranek
- Department of Oncology, Hematology, Rheumatology and Immune-Oncology, University Hospital Bonn, 53127 Bonn, Germany; (R.L.); (M.L.); (S.A.J.); (A.H.)
| | - Annkristin Heine
- Department of Oncology, Hematology, Rheumatology and Immune-Oncology, University Hospital Bonn, 53127 Bonn, Germany; (R.L.); (M.L.); (S.A.J.); (A.H.)
| | - Katrin Paeschke
- Department of Oncology, Hematology, Rheumatology and Immune-Oncology, University Hospital Bonn, 53127 Bonn, Germany; (R.L.); (M.L.); (S.A.J.); (A.H.)
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13
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Zia A, Farkhondeh T, Sahebdel F, Pourbagher-Shahri AM, Samarghandian S. Key miRNAs in Modulating Aging and Longevity: A Focus on Signaling Pathways and Cellular Targets. Curr Mol Pharmacol 2021; 15:736-762. [PMID: 34533452 DOI: 10.2174/1874467214666210917141541] [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: 11/21/2020] [Revised: 05/02/2021] [Accepted: 05/24/2021] [Indexed: 11/22/2022]
Abstract
Aging is a multifactorial procedure accompanied by gradual deterioration of most biological procedures of cells. MicroRNAs (miRNAs) are a class of short non-coding RNAs that post-transcriptionally regulate the expression of mRNAs through sequence-specific binding, and contributing to many crucial aspects of cell biology. Several miRNAs are expressed differently in various organisms through aging. The function of miRNAs in modulating aging procedures has been disclosed recently with the detection of miRNAs that modulate longevity in the invertebrate model organisms, through the IIS pathway. In these model organisms, several miRNAs have been detected to both negatively and positively regulate lifespan via commonly aging pathways. miRNAs modulate age-related procedures and disorders in different mammalian tissues by measuring their tissue-specific expression in older and younger counterparts, including heart, skin, bone, brain, and muscle tissues. Moreover, several miRNAs have been contributed to modulating senescence in different human cells, and the roles of these miRNAs in modulating cellular senescence have allowed illustrating some mechanisms of aging. The review discusses the available data on miRNAs through the aging process and we highlight the roles of miRNAs as aging biomarkers and regulators of longevity in cellular senescence, tissue aging, and organism lifespan.
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Affiliation(s)
- Aliabbas Zia
- Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Tahereh Farkhondeh
- Cardiovascular Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Faezeh Sahebdel
- Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, MN, United States
| | | | - Saeed Samarghandian
- Noncommunicable Diseases Research Center, Neyshabur University of Medical Sciences, Neyshabur, Iran
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14
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Baek KW, Jung YK, Park JS, Kim JS, Hah YS, Kim SJ, Yoo JI. Two Types of Mouse Models for Sarcopenia Research: Senescence Acceleration and Genetic Modification Models. J Bone Metab 2021; 28:179-191. [PMID: 34520651 PMCID: PMC8441530 DOI: 10.11005/jbm.2021.28.3.179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022] Open
Abstract
Sarcopenia leads to loss of skeletal muscle mass, quality, and strength due to aging; it was recently given a disease code (International Classification of Diseases, Tenth Revision, Clinical Modification, M62.84). As a result, in recent years, sarcopenia-related research has increased. In addition, various studies seeking to prevent and treat sarcopenia by identifying the various mechanisms related to the reduction of skeletal muscle properties have been conducted. Previous studies have identified muscle synthesis and breakdown; investigating them has generated evidence for preventing and treating sarcopenia. Mouse models are still the most useful ones for determining mechanisms underlying sarcopenia through correlations and interventions involving specific genes and their phenotypes. Mouse models used to study sarcopenia often induce muscle atrophy by hindlimb unloading, denervation, or immobilization. Though it is less frequently used, the senescence-accelerated mouse can also be useful for sarcopenia research. Herein, we discuss cases where senescence-accelerated and genetically engineered mouse models were used in sarcopenia research and different perspectives to use them.
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Affiliation(s)
- Kyung-Wan Baek
- Department of Physical Education, Gyeongsang National University, Jinju, Korea.,Department of Orthopaedic Surgery, Gyeongsang National University Hospital, Gyeongsang National University, Jinju, Korea
| | - Youn-Kwan Jung
- Biomedical Research Institute, Gyeongsang National University Hospital, Gyeongsang National University, Jinju, Korea
| | - Jin Sung Park
- Department of Orthopaedic Surgery and Institute of Health Sciences, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Ji-Seok Kim
- Department of Physical Education, Gyeongsang National University, Jinju, Korea
| | - Young-Sool Hah
- Biomedical Research Institute, Gyeongsang National University Hospital, Gyeongsang National University, Jinju, Korea
| | - So-Jeong Kim
- Department of Convergence Medical Science, Gyeongsang National University, Jinju, Korea
| | - Jun-Il Yoo
- Department of Orthopaedic Surgery, Gyeongsang National University Hospital, Gyeongsang National University, Jinju, Korea
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15
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Analysis of chromatid-break-repair detects a homologous recombination to non-homologous end-joining switch with increasing load of DNA double-strand breaks. Mutat Res 2021; 867:503372. [PMID: 34266628 DOI: 10.1016/j.mrgentox.2021.503372] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022]
Abstract
We recently reported that when low doses of ionizing radiation induce low numbers of DNA double-strand breaks (DSBs) in G2-phase cells, about 50 % of them are repaired by homologous recombination (HR) and the remaining by classical non-homologous end-joining (c-NHEJ). However, with increasing DSB-load, the contribution of HR drops to undetectable (at ∼10 Gy) as c-NHEJ dominates. It remains unknown whether the approximately equal shunting of DSBs between HR and c-NHEJ at low radiation doses and the predominant shunting to c-NHEJ at high doses, applies to every DSB, or whether the individual characteristics of each DSB generate processing preferences. When G2-phase cells are irradiated, only about 10 % of the induced DSBs break the chromatids. This breakage allows analysis of the processing of this specific subset of DSBs using cytogenetic methods. Notably, at low radiation doses, these DSBs are almost exclusively processed by HR, suggesting that chromatin characteristics awaiting characterization underpin chromatid breakage and determine the preferential engagement of HR. Strikingly, we also discovered that with increasing radiation dose, a pathway switch to c-NHEJ occurs in the processing of this subset of DSBs. Here, we confirm and substantially extend our initial observations using additional methodologies. Wild-type cells, as well as HR and c-NHEJ mutants, are exposed to a broad spectrum of radiation doses and their response analyzed specifically in G2 phase. Our results further consolidate the observation that at doses <2 Gy, HR is the main option in the processing of the subset of DSBs generating chromatid breaks and that a pathway switch at doses between 4-6 Gy allows the progressive engagement of c-NHEJ. PARP1 inhibition, irrespective of radiation dose, leaves chromatid break repair unaffected suggesting that the contribution of alternative end-joining is undetectable under these experimental conditions.
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16
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Tichy ED, Ma N, Sidibe D, Loro E, Kocan J, Chen DZ, Khurana TS, Hasty P, Mourkioti F. Persistent NF-κB activation in muscle stem cells induces proliferation-independent telomere shortening. Cell Rep 2021; 35:109098. [PMID: 33979621 PMCID: PMC8183356 DOI: 10.1016/j.celrep.2021.109098] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 11/30/2020] [Accepted: 04/16/2021] [Indexed: 12/30/2022] Open
Abstract
During the repeated cycles of damage and repair in many muscle disorders, including Duchenne muscular dystrophy (DMD), the muscle stem cell (MuSC) pool becomes less efficient at responding to and repairing damage. The underlying mechanism of such stem cell dysfunction is not fully known. Here, we demonstrate that the distinct early telomere shortening of diseased MuSCs in both mice and young DMD patients is associated with aberrant NF-κB activation. We find that prolonged NF-κB activation in MuSCs in chronic injuries leads to shortened telomeres and Ku80 dysregulation and results in severe skeletal muscle defects. Our studies provide evidence of a role for NF-κB in regulating stem-cell-specific telomere length, independently of cell replication, and could be a congruent mechanism that is applicable to additional tissues and/or diseases characterized by systemic chronic inflammation. Tichy et al. reveal a role for NF-κB signaling in regulating telomere length in muscle stem cells (MuSCs) after chronic injuries. Persistent activation of NF-κB leads to shortened telomeres, Ku80 dysregulation, and muscle defects. The findings link stem cell dysfunction and NF-κB-dependent telomere shortening in Duchenne muscular dystrophy.
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Affiliation(s)
- Elisia D Tichy
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nuoying Ma
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David Sidibe
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jacob Kocan
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Delia Z Chen
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul Hasty
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Foteini Mourkioti
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA; Institute of Regenerative Medicine, Musculoskeletal Regeneration Program, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA.
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17
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Abstract
In this perspective, we introduce shelterin and the mechanisms of ATM activation and NHEJ at telomeres, before discussing the following questions: How are t-loops proposed to protect chromosome ends and what is the evidence for this model? Can other models explain how TRF2 mediates end protection? Could t-loops be pathological structures? How is end protection achieved in pluripotent cells? What do the insights into telomere end protection in pluripotent cells mean for the t-loop model of end protection? Why might different cell states have evolved different mechanisms of end protection? Finally, we offer support for an updated t-loop model of end protection, suggesting that the data is supportive of a critical role for t-loops in protecting chromosome ends from NHEJ and ATM activation, but that other mechanisms are involved. Finally, we propose that t-loops are likely dynamic, rather than static, structures.
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Affiliation(s)
- Phil Ruis
- The Francis Crick Institute, London NW1 1AT, United Kingdom
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18
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Chen Y, Geng A, Zhang W, Qian Z, Wan X, Jiang Y, Mao Z. Fight to the bitter end: DNA repair and aging. Ageing Res Rev 2020; 64:101154. [PMID: 32977059 DOI: 10.1016/j.arr.2020.101154] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
DNA carries the genetic information that directs complex biological processes; thus, maintaining a stable genome is critical for individual growth and development and for human health. DNA repair is a fundamental and conserved mechanism responsible for mending damaged DNA and restoring genomic stability, while its deficiency is closely related to multiple human disorders. In recent years, remarkable progress has been made in the field of DNA repair and aging. Here, we will extensively discuss the relationship among DNA damage, DNA repair, aging and aging-associated diseases based on the latest research. In addition, the possible role of DNA repair in several potential rejuvenation strategies will be discussed. Finally, we will also review the emerging methods that may facilitate future research on DNA repair.
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19
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Sui J, Zhang S, Chen BPC. DNA-dependent protein kinase in telomere maintenance and protection. Cell Mol Biol Lett 2020; 25:2. [PMID: 31988640 PMCID: PMC6969447 DOI: 10.1186/s11658-020-0199-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/02/2020] [Indexed: 12/12/2022] Open
Abstract
This review focuses on DNA-dependent protein kinase (DNA-PK), which is the key regulator of canonical non-homologous end-joining (NHEJ), the predominant mechanism of DNA double-strand break (DSB) repair in mammals. DNA-PK consists of the DNA-binding Ku70/80 heterodimer and the catalytic subunit DNA-PKcs. They assemble at DNA ends, forming the active DNA-PK complex, which initiates NHEJ-mediated DSB repair. Paradoxically, both Ku and DNA-PKcs are associated with telomeres, and they play crucial roles in protecting the telomere against fusions. Herein, we discuss possible mechanisms and contributions of Ku and DNA-PKcs in telomere regulation.
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Affiliation(s)
- Jiangdong Sui
- 1Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, 400030 China
| | - Shichuan Zhang
- 2Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China
| | - Benjamin P C Chen
- 3Department of Radiation Oncology, University of Texas Southwestern Medical Center, 2201 Inwood Rd., Dallas, TX 75390-9187 USA
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20
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Červenák F, Juríková K, Devillers H, Kaffe B, Khatib A, Bonnell E, Sopkovičová M, Wellinger RJ, Nosek J, Tzfati Y, Neuvéglise C, Tomáška Ľ. Identification of telomerase RNAs in species of the Yarrowia clade provides insights into the co-evolution of telomerase, telomeric repeats and telomere-binding proteins. Sci Rep 2019; 9:13365. [PMID: 31527614 PMCID: PMC6746865 DOI: 10.1038/s41598-019-49628-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
Telomeric repeats in fungi of the subphylum Saccharomycotina exhibit great inter- and intra-species variability in length and sequence. Such variations challenged telomeric DNA-binding proteins that co-evolved to maintain their functions at telomeres. Here, we compare the extent of co-variations in telomeric repeats, encoded in the telomerase RNAs (TERs), and the repeat-binding proteins from 13 species belonging to the Yarrowia clade. We identified putative TER loci, analyzed their sequence and secondary structure conservation, and predicted functional elements. Moreover, in vivo complementation assays with mutant TERs showed the functional importance of four novel TER substructures. The TER-derived telomeric repeat unit of all species, except for one, is 10 bp long and can be represented as 5′-TTNNNNAGGG-3′, with repeat sequence variations occuring primarily outside the vertebrate telomeric motif 5′-TTAGGG-3′. All species possess a homologue of the Yarrowia lipolytica Tay1 protein, YlTay1p. In vitro, YlTay1p displays comparable DNA-binding affinity to all repeat variants, suggesting a conserved role among these species. Taken together, these results add significant insights into the co-evolution of TERs, telomeric repeats and telomere-binding proteins in yeasts.
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Affiliation(s)
- Filip Červenák
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Katarína Juríková
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Hugo Devillers
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Binyamin Kaffe
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Areej Khatib
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Erin Bonnell
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Martina Sopkovičová
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Raymund J Wellinger
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Jozef Nosek
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel.
| | - Cécile Neuvéglise
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
| | - Ľubomír Tomáška
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia.
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21
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Maekawa T, Liu B, Nakai D, Yoshida K, Nakamura KI, Yasukawa M, Koike M, Takubo K, Chatton B, Ishikawa F, Masutomi K, Ishii S. ATF7 mediates TNF-α-induced telomere shortening. Nucleic Acids Res 2019; 46:4487-4504. [PMID: 29490055 PMCID: PMC5961373 DOI: 10.1093/nar/gky155] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 02/20/2018] [Indexed: 12/23/2022] Open
Abstract
Telomeres maintain the integrity of chromosome ends and telomere length is an important marker of aging. The epidemiological studies suggested that many types of stress including psychosocial stress decrease telomere length. However, it remains unknown how various stresses induce telomere shortening. Here, we report that the stress-responsive transcription factor ATF7 mediates TNF-α–induced telomere shortening. ATF7 and telomerase, an enzyme that elongates telomeres, are localized on telomeres via interactions with the Ku complex. In response to TNF-α, which is induced by various stresses including psychological stress, ATF7 was phosphorylated by p38, leading to the release of ATF7 and telomerase from telomeres. Thus, a decrease of ATF7 and telomerase on telomeres in response to stress causes telomere shortening, as observed in ATF7-deficient mice. These findings give credence to the idea that various types of stress might shorten telomere.
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Affiliation(s)
- Toshio Maekawa
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Binbin Liu
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Daisuke Nakai
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Keisuke Yoshida
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Ken-Ichi Nakamura
- Research Team for Geriatric Diseases, Tokyo Metropolitan Institute of Gerontology, Sakaecho 35-2, Itabashi-ku, Tokyo 173-0015, Japan
| | - Mami Yasukawa
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, Japan
| | - Manabu Koike
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kaiyo Takubo
- Research Team for Geriatric Diseases, Tokyo Metropolitan Institute of Gerontology, Sakaecho 35-2, Itabashi-ku, Tokyo 173-0015, Japan
| | - Bruno Chatton
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Fuyuki Ishikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kenkichi Masutomi
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, Japan
| | - Shunsuke Ishii
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
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22
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Nenarokova A, Záhonová K, Krasilnikova M, Gahura O, McCulloch R, Zíková A, Yurchenko V, Lukeš J. Causes and Effects of Loss of Classical Nonhomologous End Joining Pathway in Parasitic Eukaryotes. mBio 2019; 10:e01541-19. [PMID: 31311886 PMCID: PMC6635534 DOI: 10.1128/mbio.01541-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 01/22/2023] Open
Abstract
We report frequent losses of components of the classical nonhomologous end joining pathway (C-NHEJ), one of the main eukaryotic tools for end joining repair of DNA double-strand breaks, in several lineages of parasitic protists. Moreover, we have identified a single lineage among trypanosomatid flagellates that has lost Ku70 and Ku80, the core C-NHEJ components, and accumulated numerous insertions in many protein-coding genes. We propose a correlation between these two phenomena and discuss the possible impact of the C-NHEJ loss on genome evolution and transition to the parasitic lifestyle.IMPORTANCE Parasites tend to evolve small and compact genomes, generally endowed with a high mutation rate, compared with those of their free-living relatives. However, the mechanisms by which they achieve these features, independently in unrelated lineages, remain largely unknown. We argue that the loss of the classical nonhomologous end joining pathway components may be one of the crucial steps responsible for characteristic features of parasite genomes.
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Affiliation(s)
- Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Marija Krasilnikova
- Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Richard McCulloch
- Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Vyacheslav Yurchenko
- Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
- Life Science Research Centre and Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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23
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Abstract
Bacteria and viruses possess circular DNA, whereas eukaryotes with typically very large DNA molecules have had to evolve into linear chromosomes to circumvent the problem of supercoiling circular DNA of that size. Consequently, such organisms possess telomeres to cap chromosome ends. Telomeres are essentially tandem repeats of any DNA sequence that are present at the ends of chromosomes. Their biology has been an enigmatic one, involving various molecules interacting dynamically in an evolutionarily well-trimmed fashion. Telomeres range from canonical hexameric repeats in most eukaryotes to unimaginably random retrotransposons, which attach to chromosome ends and reverse-transcribe to DNA in some plants and insects. Telomeres invariably associate with specialised protein complexes that envelop it, also regulating access of the ends to legitimate enzymes involved in telomere metabolism. They also transcribe into repetitive RNA which also seems to be playing significant roles in telomere maintenance. Telomeres thus form the intersection of DNA, protein, and RNA molecules acting in concert to maintain chromosome integrity. Telomere biology is emerging to appear ever more complex than previously envisaged, with the continual discovery of more molecules and interplays at the telomeres. This review also includes a section dedicated to the history of telomere biology, and intends to target the scientific audience new to the field by rendering an understanding of the phenomenon of chromosome end protection at large, with more emphasis on the biology of human telomeres. The review provides an update on the field and mentions the questions that need to be addressed.
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Affiliation(s)
- Shriram Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
| | - Aik Kia Khaw
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Clinical Research Unit, Khoo Teck Puat Hospital, 768828 Singapore, Singapore.
| | - Manoor Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Tembusu College, National University of Singapore, 138598 Singapore, Singapore.
- VIT University, Vellore 632014, India.
- Mangalore University, Mangalore 574199, India.
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Simon NE, Yuan M, Kai M. RNA-binding protein RBM14 regulates dissociation and association of non-homologous end joining proteins. Cell Cycle 2017; 16:1175-1180. [PMID: 28426349 DOI: 10.1080/15384101.2017.1317419] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Defects in the DNA damage response (DDR) are associated with multiple diseases, including cancers and neurodegenerative disorders. Emerging evidence indicates involvement of RNA-binding proteins (RBPs) in DDR. However, functions of RBPs in the DDR pathway remain elusive. We have shown previously that the RNA-binding protein RBM14 is required for non-homologous end joining (NHEJ). Here we show that RBM14 is required for efficient recruitment of XRCC4 and XLF to chromatin and the release of KU proteins from chromatin upon DNA damage. Failure of this process leads to accumulation of double-strand breaks (DSBs) in cells. Thus RBM14 plays crucial role in regulation of NHEJ upon DNA damage.
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Affiliation(s)
- Nicholas E Simon
- a Department of Radiation Oncology, Department of Pathology , Johns Hopkins University, School of Medicine , Baltimore , MD , USA
| | - Ming Yuan
- a Department of Radiation Oncology, Department of Pathology , Johns Hopkins University, School of Medicine , Baltimore , MD , USA.,b Department of Pathology , Johns Hopkins University, School of Medicine , Baltimore , MD , USA
| | - Mihoko Kai
- a Department of Radiation Oncology, Department of Pathology , Johns Hopkins University, School of Medicine , Baltimore , MD , USA
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25
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Schuhwerk H, Atteya R, Siniuk K, Wang ZQ. PARPing for balance in the homeostasis of poly(ADP-ribosyl)ation. Semin Cell Dev Biol 2016; 63:81-91. [PMID: 27664469 DOI: 10.1016/j.semcdb.2016.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 12/12/2022]
Abstract
Despite more than 50 years of research, the vast majority of the biology of poly(ADP-ribosyl)ation (PARylation) still remains a gross mystery. Originally described to be a part of the DNA repair machinery, poly(ADP-ribose) (PAR) is synthesized immediately by poly(ADP-ribose) polymerases (PARPs, also known as ARTDs) upon DNA damage and then rapidly removed by degrading enzymes. PAR provides a delicate and spatiotemporal interaction scaffold for numerous target proteins. Thus, the multifaceted PARylation system, consisting of PAR itself and its synthesizers and erasers, plays diverse roles in the DNA damage response (DDR), in DNA repair, transcription, replication, chromatin remodelling, metabolism and cell death. In this review, we summarize the current understanding of the biology of PARylation, focusing on the functionality and the activities of the PARPs' founding member PARP1/ARTD1, which is modulated by a variety of posttranslational modifications. We also discuss the homeostasis of PAR - a process which is maintained by the balance of PAR synthesizers and erasers. We aim to sensitize the scientific community to the complexity of PAR homeostasis. Finally, we provide some perspective on how future research could try to disentangle the biology of PARylation - perhaps the most sophisticated, but still intricate posttranslational modification described to date.
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Affiliation(s)
- Harald Schuhwerk
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Reham Atteya
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Kanstantsin Siniuk
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany; Faculty of Biology and Pharmacy, Friedrich Schiller University Jena, Fürstengraben 1, 07743 Jena, Germany.
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Lee SS, Bohrson C, Pike AM, Wheelan SJ, Greider CW. ATM Kinase Is Required for Telomere Elongation in Mouse and Human Cells. Cell Rep 2015; 13:1623-32. [PMID: 26586427 PMCID: PMC4663052 DOI: 10.1016/j.celrep.2015.10.035] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/11/2015] [Accepted: 10/11/2015] [Indexed: 12/26/2022] Open
Abstract
Short telomeres induce a DNA damage response, senescence, and apoptosis, thus maintaining telomere length equilibrium is essential for cell viability. Telomerase addition of telomere repeats is tightly regulated in cells. To probe pathways that regulate telomere addition, we developed the ADDIT assay to measure new telomere addition at a single telomere in vivo. Sequence analysis showed telomerase-specific addition of repeats onto a new telomere occurred in just 48 hr. Using the ADDIT assay, we found that ATM is required for addition of new repeats onto telomeres in mouse cells. Evaluation of bulk telomeres, in both human and mouse cells, showed that blocking ATM inhibited telomere elongation. Finally, the activation of ATM through the inhibition of PARP1 resulted in increased telomere elongation, supporting the central role of the ATM pathway in regulating telomere addition. Understanding this role of ATM may yield new areas for possible therapeutic intervention in telomere-mediated disease.
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Affiliation(s)
- Stella Suyong Lee
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Predoctoral Training Program in Human Genetics and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Craig Bohrson
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alexandra Mims Pike
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sarah Jo Wheelan
- Predoctoral Training Program in Human Genetics and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Carol Widney Greider
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Predoctoral Training Program in Human Genetics and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
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Yoon JS, Hwang DW, Kim ES, Kim JS, Kim S, Chung HJ, Lee SK, Yi JH, Uhm J, Won YW, Park BB, Choi JH, Lee YY. Anti-tumoral effect of arsenic compound, sodium metaarsenite (KML001), in non-Hodgkin’s lymphoma: an in vitro and in vivo study. Invest New Drugs 2015; 34:1-14. [DOI: 10.1007/s10637-015-0301-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 11/01/2015] [Indexed: 12/13/2022]
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Venkatesan S, Natarajan AT, Hande MP. Chromosomal instability--mechanisms and consequences. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:176-84. [PMID: 26520388 DOI: 10.1016/j.mrgentox.2015.08.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 01/08/2023]
Abstract
Chromosomal instability is defined as a state of numerical and/or structural chromosomal anomalies in cells. Numerous studies have documented the incidence of chromosomal instability, which acutely or chronically may lead to accelerated ageing (tissue-wide or even organismal), cancer or other genetic disorders. Potential mechanisms leading to the generation of chromosome-genome instability include erroneous/inefficient DNA repair, chromosome segregation defects, spindle assembly defects, DNA replication stress, telomere shortening/dysfunction - to name a few. Understanding the cellular and molecular mechanisms for chromosomal instability in various human cells and tissues will be useful in elucidating the cause for many age associated diseases including cancer. This approach holds a great promise for the cytogenetic assays not only for prognosis but also for diagnostic purposes in clinical settings. In this review, a multi-dimensional approach has been attempted to portray the complexity behind the incidence of chromosome-genome instability including evolutionary implications at the species level for some of the mechanisms of chromosomal instability.
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Affiliation(s)
- Shriram Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597
| | - Adayapalam T Natarajan
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo 01100, Italy
| | - M Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597; Tembusu College, National University of Singapore, Singapore, 138597.
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YOON JINSUN, KIM EUNSHIL, PARK BYEONGBAE, CHOI JUNGHYE, WON YOUNGWOONG, KIM SUJONG, LEE YOUNGYIUL. Anti-leukemic effect of sodium metaarsenite (KML001) in acute myeloid leukemia with breaking-down the resistance of cytosine arabinoside. Int J Oncol 2015; 46:1953-62. [DOI: 10.3892/ijo.2015.2899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/29/2014] [Indexed: 11/06/2022] Open
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de Sena-Tomás C, Yu EY, Calzada A, Holloman WK, Lue NF, Pérez-Martín J. Fungal Ku prevents permanent cell cycle arrest by suppressing DNA damage signaling at telomeres. Nucleic Acids Res 2015; 43:2138-51. [PMID: 25653166 PMCID: PMC4344518 DOI: 10.1093/nar/gkv082] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The Ku heterodimer serves in the initial step in repairing DNA double-strand breaks by the non-homologous end-joining pathway. Besides this key function, Ku also plays a role in other cellular processes including telomere maintenance. Inactivation of Ku can lead to DNA repair defects and telomere aberrations. In model organisms where Ku has been studied, inactivation can lead to DNA repair defects and telomere aberrations. In general Ku deficient mutants are viable, but a notable exception to this is human where Ku has been found to be essential. Here we report that similar to the situation in human Ku is required for cell proliferation in the fungus Ustilago maydis. Using conditional strains for Ku expression, we found that cells arrest permanently in G2 phase when Ku expression is turned off. Arrest results from cell cycle checkpoint activation due to persistent signaling via the DNA damage response (DDR). Our results point to the telomeres as the most likely source of the DNA damage signal. Inactivation of the DDR makes the Ku complex dispensable for proliferation in this organism. Our findings suggest that in U. maydis, unprotected telomeres arising from Ku depletion are the source of the signal that activates the DDR leading to cell cycle arrest.
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Affiliation(s)
- Carmen de Sena-Tomás
- Instituto de Biología Funcional y Genómica (CSIC), Zacarías González 2, 37007 Salamanca, Spain
| | - Eun Young Yu
- Department of Microbiology and Immunology, Weill Cornell Cancer Center, Weill Medical College of Cornell University, New York, 10021 NY, USA
| | - Arturo Calzada
- Centro Nacional de Biotecnología (CSIC), 28049 Madrid, Spain
| | - William K Holloman
- Department of Microbiology and Immunology, Weill Cornell Cancer Center, Weill Medical College of Cornell University, New York, 10021 NY, USA
| | - Neal F Lue
- Department of Microbiology and Immunology, Weill Cornell Cancer Center, Weill Medical College of Cornell University, New York, 10021 NY, USA
| | - José Pérez-Martín
- Instituto de Biología Funcional y Genómica (CSIC), Zacarías González 2, 37007 Salamanca, Spain
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DNA Double-Strand Break Repair Inhibitors as Cancer Therapeutics. ACTA ACUST UNITED AC 2015; 22:17-29. [DOI: 10.1016/j.chembiol.2014.11.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 10/26/2014] [Accepted: 11/10/2014] [Indexed: 12/29/2022]
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Gurung RL, Lim HK, Venkatesan S, Lee PSW, Hande MP. Targeting DNA-PKcs and telomerase in brain tumour cells. Mol Cancer 2014; 13:232. [PMID: 25307264 PMCID: PMC4213508 DOI: 10.1186/1476-4598-13-232] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 10/07/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Patients suffering from brain tumours such as glioblastoma and medulloblastoma have poor prognosis with a median survival of less than a year. Identifying alternative molecular targets would enable us to develop different therapeutic strategies for better management of these tumours. METHODS Glioblastoma (MO59K and KNS60) and medulloblastoma cells (ONS76) were used in this study. Telomerase inhibitory effects of MST-312, a chemically modified-derivative of epigallocatechin gallate, in the cells were assessed using telomere repeat amplification protocol. Gene expression analysis following MST-312 treatment was done by microarray. Telomere length was measured by telomere restriction fragments analysis. Effects of MST-312 on DNA integrity were evaluated by single cell gel electrophoresis, immunofluorescence assay and cytogenetic analysis. Phosphorylation status of DNA-PKcs was measured with immunoblotting and effects on cell proliferation were monitored with cell titre glow and trypan blue exclusion following dual inhibition. RESULTS MST-312 showed strong binding affinity to DNA and displayed reversible telomerase inhibitory effects in brain tumour cells. In addition to the disruption of telomere length maintenance, MST-312 treatment decreased brain tumour cell viability, induced cell cycle arrest and double strand breaks (DSBs). DNA-PKcs activation was observed in telomerase-inhibited cells presumably as a response to DNA damage. Impaired DNA-PKcs in MO59J cells or in MO59K cells treated with DNA-PKcs inhibitor, NU7026, caused a delay in the repair of DSBs. In contrast, MST-312 did not induce DSBs in telomerase negative osteosarcoma cells (U2OS). Combined inhibition of DNA-PKcs and telomerase resulted in an increase in telomere signal-free chromosomal ends in brain tumour cells as well. Interestingly, continual exposure of brain tumour cells to telomerase inhibitor led to population of cells, which displayed resistance to telomerase inhibition-mediated cell arrest. DNA-PKcs ablation in these cells, however, confers higher cell sensitivity to telomerase inhibition, inducing cell death. CONCLUSIONS Efficient telomerase inhibition was achieved with acute exposure to MST-312 and this resulted in subtle but significant increase in DSBs. Activation of DNA-PKcs might indicate the requirement of NHEJ pathway in the repair telomerase inhibitor induced DNA damage. Therefore, our results suggest a potential strategy in combating brain tumour cells with dual inhibition of telomerase and NHEJ pathway.
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Affiliation(s)
| | | | | | | | - M Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, Singapore 117597, Singapore.
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Johnson RM, Papp E, Grandal I, Kowalski PE, Nutter L, Wong RCC, Joseph-George AM, Danska JS, Guidos CJ. MuLV-related endogenous retroviral elements and Flt3 participate in aberrant end-joining events that promote B-cell leukemogenesis. Genes Dev 2014; 28:1179-90. [PMID: 24888589 PMCID: PMC4052764 DOI: 10.1101/gad.240820.114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice. Johnson et al. identified a novel class of activating mutations in Flt3 in Rag/p53/NHEJ triple-mutant B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements. Mutant Flt3 induced ligand-independent STAT5 phosphorylation and promoted development of clinically aggressive B-cell leukemia. During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2, thus maintaining genomic stability and limiting malignant transformation during B-cell development. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice, revealing that p53 and NHEJ also suppress Rag-independent mechanisms of B-cell leukemogenesis. Using several cytogenomic approaches, we identified a novel class of activating mutations in Fms-like tyrosine kinase 3 (Flt3), a receptor tyrosine kinase important for normal hematopoiesis in Rag/p53/NHEJ triple-mutant (TM) B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements, generating ERV-Flt3 fusion genes encoding an N-terminally truncated mutant form of Flt3 (trFlt3) that was transcribed from ERV long terminal repeats. trFlt3 protein lacked most of the Flt3 extracellular domain and induced ligand-independent STAT5 phosphorylation and proliferation of hematopoietic progenitor cells. Furthermore, expression of trFlt3 in p53/NHEJ mutant hematopoietic progenitor cells promoted development of clinically aggressive B-cell leukemia. Thus, repetitive MuLV-related ERV sequences can participate in aberrant end-joining events that promote development of aggressive B-cell leukemia.
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Affiliation(s)
- Radia M Johnson
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Immunology
| | - Eniko Papp
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ildiko Grandal
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Paul E Kowalski
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Lauryl Nutter
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Raymond C C Wong
- The Centre for Applied Genomics, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Ann M Joseph-George
- The Centre for Applied Genomics, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Jayne S Danska
- Department of Immunology, Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Cynthia J Guidos
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Immunology
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The Ku heterodimer: function in DNA repair and beyond. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:15-29. [PMID: 25795113 DOI: 10.1016/j.mrrev.2014.06.002] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/07/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023]
Abstract
Ku is an abundant, highly conserved DNA binding protein found in both prokaryotes and eukaryotes that plays essential roles in the maintenance of genome integrity. In eukaryotes, Ku is a heterodimer comprised of two subunits, Ku70 and Ku80, that is best characterized for its central role as the initial DNA end binding factor in the "classical" non-homologous end joining (C-NHEJ) pathway, the main DNA double-strand break (DSB) repair pathway in mammals. Ku binds double-stranded DNA ends with high affinity in a sequence-independent manner through a central ring formed by the intertwined strands of the Ku70 and Ku80 subunits. At the break, Ku directly and indirectly interacts with several C-NHEJ factors and processing enzymes, serving as the scaffold for the entire DNA repair complex. There is also evidence that Ku is involved in signaling to the DNA damage response (DDR) machinery to modulate the activation of cell cycle checkpoints and the activation of apoptosis. Interestingly, Ku is also associated with telomeres, where, paradoxically to its DNA end-joining functions, it protects the telomere ends from being recognized as DSBs, thereby preventing their recombination and degradation. Ku, together with the silent information regulator (Sir) complex is also required for transcriptional silencing through telomere position effect (TPE). How Ku associates with telomeres, whether it is through direct DNA binding, or through protein-protein interactions with other telomere bound factors remains to be determined. Ku is central to the protection of organisms through its participation in C-NHEJ to repair DSBs generated during V(D)J recombination, a process that is indispensable for the establishment of the immune response. Ku also functions to prevent tumorigenesis and senescence since Ku-deficient mice show increased cancer incidence and early onset of aging. Overall, Ku function is critical to the maintenance of genomic integrity and to proper cellular and organismal development.
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Stewart DR, Pemov A, Johnston JJ, Sapp JC, Yeager M, He J, Boland JF, Burdett L, Brown C, Gatti RA, Alter BP, Biesecker LG, Savage SA. Dubowitz syndrome is a complex comprised of multiple, genetically distinct and phenotypically overlapping disorders. PLoS One 2014; 9:e98686. [PMID: 24892279 PMCID: PMC4043752 DOI: 10.1371/journal.pone.0098686] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 05/04/2014] [Indexed: 12/14/2022] Open
Abstract
Dubowitz syndrome is a rare disorder characterized by multiple congenital anomalies, cognitive delay, growth failure, an immune defect, and an increased risk of blood dyscrasia and malignancy. There is considerable phenotypic variability, suggesting genetic heterogeneity. We clinically characterized and performed exome sequencing and high-density array SNP genotyping on three individuals with Dubowitz syndrome, including a pair of previously-described siblings (Patients 1 and 2, brother and sister) and an unpublished patient (Patient 3). Given the siblings' history of bone marrow abnormalities, we also evaluated telomere length and performed radiosensitivity assays. In the siblings, exome sequencing identified compound heterozygosity for a known rare nonsense substitution in the nuclear ligase gene LIG4 (rs104894419, NM_002312.3:c.2440C>T) that predicts p.Arg814X (MAF:0.0002) and an NM_002312.3:c.613delT variant that predicts a p.Ser205Leufs*29 frameshift. The frameshift mutation has not been reported in 1000 Genomes, ESP, or ClinSeq. These LIG4 mutations were previously reported in the sibling sister; her brother had not been previously tested. Western blotting showed an absence of a ligase IV band in both siblings. In the third patient, array SNP genotyping revealed a de novo ∼3.89 Mb interstitial deletion at chromosome 17q24.2 (chr 17:62,068,463–65,963,102, hg18), which spanned the known Carney complex gene PRKAR1A. In all three patients, a median lymphocyte telomere length of ≤1st centile was observed and radiosensitivity assays showed increased sensitivity to ionizing radiation. Our work suggests that, in addition to dyskeratosis congenita, LIG4 and 17q24.2 syndromes also feature shortened telomeres; to confirm this, telomere length testing should be considered in both disorders. Taken together, our work and other reports on Dubowitz syndrome, as currently recognized, suggest that it is not a unitary entity but instead a collection of phenotypically similar disorders. As a clinical entity, Dubowitz syndrome will need continual re-evaluation and re-definition as its constituent phenotypes are determined.
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Affiliation(s)
- Douglas R. Stewart
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
- * E-mail:
| | - Alexander Pemov
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Jennifer J. Johnston
- Genetic Disease Research Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, United States of America
| | - Julie C. Sapp
- Genetic Disease Research Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, United States of America
| | - Meredith Yeager
- Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Ji He
- Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Joseph F. Boland
- Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Laurie Burdett
- Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Christina Brown
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Richard A. Gatti
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
- Department of Human Genetics, David Geffen UCLA School of Medicine, Los Angeles, California, United States of America
| | - Blanche P. Alter
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
| | - Leslie G. Biesecker
- Genetic Disease Research Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, United States of America
| | - Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, Maryland, United States of America
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Frit P, Barboule N, Yuan Y, Gomez D, Calsou P. Alternative end-joining pathway(s): bricolage at DNA breaks. DNA Repair (Amst) 2014; 17:81-97. [PMID: 24613763 DOI: 10.1016/j.dnarep.2014.02.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 02/01/2014] [Accepted: 02/10/2014] [Indexed: 10/25/2022]
Abstract
To cope with DNA double strand break (DSB) genotoxicity, cells have evolved two main repair pathways: homologous recombination which uses homologous DNA sequences as repair templates, and non-homologous Ku-dependent end-joining involving direct sealing of DSB ends by DNA ligase IV (Lig4). During the last two decades a third player most commonly named alternative end-joining (A-EJ) has emerged, which is defined as any Ku- or Lig4-independent end-joining process. A-EJ increasingly appears as a highly error-prone bricolage on DSBs and despite expanding exploration, it still escapes full characterization. In the present review, we discuss the mechanism and regulation of A-EJ as well as its biological relevance under physiological and pathological situations, with a particular emphasis on chromosomal instability and cancer. Whether or not it is a genuine DSB repair pathway, A-EJ is emerging as an important cellular process and understanding A-EJ will certainly be a major challenge for the coming years.
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Affiliation(s)
- Philippe Frit
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, 31077 Toulouse, Cedex4, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France; Equipe labellisée Ligue Nationale Contre le Cancer, France
| | - Nadia Barboule
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, 31077 Toulouse, Cedex4, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France; Equipe labellisée Ligue Nationale Contre le Cancer, France
| | - Ying Yuan
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, 31077 Toulouse, Cedex4, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France; Equipe labellisée Ligue Nationale Contre le Cancer, France
| | - Dennis Gomez
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, 31077 Toulouse, Cedex4, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France; Equipe labellisée Ligue Nationale Contre le Cancer, France
| | - Patrick Calsou
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, 31077 Toulouse, Cedex4, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France; Equipe labellisée Ligue Nationale Contre le Cancer, France.
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Kuhmann C, Li C, Kloor M, Salou M, Weigel C, Schmidt CR, Ng LWC, Tsui WWY, Leung SY, Yuen ST, Becker N, Weichenhan D, Plass C, Schmezer P, Chan TL, Popanda O. Altered regulation of DNA ligase IV activity by aberrant promoter DNA methylation and gene amplification in colorectal cancer. Hum Mol Genet 2013; 23:2043-54. [PMID: 24282031 DOI: 10.1093/hmg/ddt599] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Colorectal cancer (CRC) presents as a very heterogeneous disease which cannot sufficiently be characterized with the currently known genetic and epigenetic markers. To identify new markers for CRC we scrutinized the methylation status of 231 DNA repair-related genes by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression of these genes could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A and LIG4 in CRC which was confirmed in two CRC patient groups with different ethnicity. DNA ligase IV (LIG4) showed strong differential promoter methylation (up to 60%) which coincided with downregulation of mRNA in 51% of cases. This functional association of LIG4 methylation and gene expression was supported by LIG4 re-expression in 5-aza-2'-deoxycytidine-treated colon cancer cell lines, and reduced ligase IV amounts and end-joining activity in extracts of tumors with hypermethylation. Methylation of LIG4 was not associated with other genetic and epigenetic markers of CRC in our study. As LIG4 is located on chromosome 13 which is frequently amplified in CRC, two loci were tested for gene amplification in a subset of 47 cases. Comparison of amplification, methylation and expression data revealed that, in 30% of samples, the LIG4 gene was amplified and methylated, but expression was not changed. In conclusion, hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for CRC independent of known markers.
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Kang GY, Pyun BJ, Seo HR, Jin YB, Lee HJ, Lee YJ, Lee YS. Inhibition of Snail1-DNA-PKcs protein-protein interface sensitizes cancer cells and inhibits tumor metastasis. J Biol Chem 2013; 288:32506-32516. [PMID: 24085291 DOI: 10.1074/jbc.m113.479840] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Our previous study suggested that the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) interacts with Snail1, which affects genomic instability, sensitivity to DNA-damaging agents, and migration of tumor cells by reciprocal regulation between DNA-PKcs and Snail1. Here, we further investigate that a peptide containing 7-amino acid sequences (amino acids 15-21) of Snail1 (KPNYSEL, SP) inhibits the endogenous interaction between DNA-PKcs and Snail1 through primary interaction with DNA-PKcs. SP restored the inhibited DNA-PKcs repair activity and downstream pathways. On the other hand, DNA-PKcs-mediated phosphorylation of Snail1 was inhibited by SP, which resulted in decreased Snail1 stability and Snail1 functions. However, these phenomena were only shown in p53 wild-type cells, not in p53-defective cells. From these results, it is suggested that interfering with the protein interaction between DNA-PKcs and Snail1 might be an effective strategy for sensitizing cancer cells and inhibiting tumor migration, especially in both Snail1-overexpressing and DNA-PKcs-overexpressing cancer cells with functional p53.
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Affiliation(s)
- Ga-Young Kang
- From the College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750
| | - Bo-Jeong Pyun
- From the College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750
| | - Haeng Ran Seo
- the Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706
| | - Yeung Bae Jin
- the Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup-si, Jeollabuk-do 580-185, Korea
| | - Hae-June Lee
- the Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706
| | - Yoon-Jin Lee
- the Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706
| | - Yun-Sil Lee
- From the College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750,.
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Abstract
Fusion genes that are caused by chromosome translocations have been recognized for several decades as drivers of deregulated cell growth in certain types of cancer. In recent years, oncogenic fusion genes have been found in many haematological and solid tumours, demonstrating that translocations are a common cause of malignancy. Sequencing approaches have now confirmed that numerous, non-clonal translocations are a typical feature of cancer cells. These chromosome rearrangements are often highly complex and contain DNA sequence from multiple genomic sites. The factors and pathways that promote translocations are becoming clearer, with non-homologous end-joining implicated as a key source of genomic rearrangements.
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Affiliation(s)
- Samuel F Bunting
- Rutgers University, Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey 08854, USA.
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40
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Romanick M, Thompson LV, Brown-Borg HM. Murine models of atrophy, cachexia, and sarcopenia in skeletal muscle. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1410-20. [PMID: 23523469 DOI: 10.1016/j.bbadis.2013.03.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/10/2013] [Accepted: 03/12/2013] [Indexed: 12/11/2022]
Abstract
With the extension of life span over the past several decades, the age-related loss of muscle mass and strength that characterizes sarcopenia is becoming more evident and thus, has a more significant impact on society. To determine ways to intervene and delay, or even arrest the physical frailty and dependence that accompany sarcopenia, it is necessary to identify those biochemical pathways that define this process. Animal models that mimic one or more of the physiological pathways involved with this phenomenon are very beneficial in providing an understanding of the cellular processes at work in sarcopenia. The ability to influence pathways through genetic manipulation gives insight into cellular responses and their impact on the physical expression of sarcopenia. This review evaluates several murine models that have the potential to elucidate biochemical processes integral to sarcopenia. Identifying animal models that reflect sarcopenia or its component pathways will enable researchers to better understand those pathways that contribute to age-related skeletal muscle mass loss, and in turn, develop interventions that will prevent, retard, arrest, or reverse this phenomenon. This article is part of a Special Issue entitled: Animal Models of Disease.
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Affiliation(s)
- Mark Romanick
- Department of Physical Therapy, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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41
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Galati A, Micheli E, Cacchione S. Chromatin structure in telomere dynamics. Front Oncol 2013; 3:46. [PMID: 23471416 PMCID: PMC3590461 DOI: 10.3389/fonc.2013.00046] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 02/21/2013] [Indexed: 11/13/2022] Open
Abstract
The establishment of a specific nucleoprotein structure, the telomere, is required to ensure the protection of chromosome ends from being recognized as DNA damage sites. Telomere shortening below a critical length triggers a DNA damage response that leads to replicative senescence. In normal human somatic cells, characterized by telomere shortening with each cell division, telomere uncapping is a regulated process associated with cell turnover. Nevertheless, telomere dysfunction has also been associated with genomic instability, cell transformation, and cancer. Despite the essential role telomeres play in chromosome protection and in tumorigenesis, our knowledge of the chromatin structure involved in telomere maintenance is still limited. Here we review the recent findings on chromatin modifications associated with the dynamic changes of telomeres from protected to deprotected state and their role in telomere functions.
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Affiliation(s)
- Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Istituto Pasteur - Fondazione Cenci Bolognetti, Sapienza Università di Roma Rome, Italy
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42
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Oh S, Wang Y, Zimbric J, Hendrickson EA. Human LIGIV is synthetically lethal with the loss of Rad54B-dependent recombination and is required for certain chromosome fusion events induced by telomere dysfunction. Nucleic Acids Res 2012; 41:1734-49. [PMID: 23275564 PMCID: PMC3561972 DOI: 10.1093/nar/gks1326] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Classic non-homologous end joining (C-NHEJ) is the predominant DNA double-strand break repair pathway in humans. Although seven genes Ku70, Ku86, DNA-PKcs, Artemis, DNA Ligase IV (LIGIV), X-ray cross-complementing group 4 and XRCC4-like factor are required for C-NHEJ, several of them also have ancillary functions. For example, Ku70:Ku86 possesses an essential telomere maintenance activity. In contrast, LIGIV is believed to function exclusively in C-NHEJ. Moreover, a viable LIGIV-null human B-cell line and LIGIV-reduced patient cell lines have been described. Together, these observations suggest that LIGIV (and hence C-NHEJ), albeit important, is nonetheless dispensable, whereas Ku70:Ku86 and telomere maintenance are essential. To confirm this hypothesis, we inactivated LIGIV in the epithelial human cell line, HCT116. The resulting LIGIV-null cell line was viable, verifying that the gene and C-NHEJ are not essential. However, functional inactivation of RAD54B, a key homologous recombination factor, in the LIGIV-null background yielded no viable clones, suggesting that the combined absence of RAD54B/homologous recombination and C-NHEJ is synthetically lethal. Finally, we demonstrate that LIGIV is differentially required for certain chromosome fusion events induced by telomere dysfunction—used for those owing to the overexpression of a dominant negative version of telomere recognition factor 2, but not used for those owing to absence of Ku70:Ku86.
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Affiliation(s)
- Sehyun Oh
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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43
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Bugeja HE, Boyce KJ, Weerasinghe H, Beard S, Jeziorowski A, Pasricha S, Payne M, Schreider L, Andrianopoulos A. Tools for high efficiency genetic manipulation of the human pathogen Penicillium marneffei. Fungal Genet Biol 2012; 49:772-8. [DOI: 10.1016/j.fgb.2012.08.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 08/08/2012] [Accepted: 08/08/2012] [Indexed: 12/19/2022]
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Didier N, Hourdé C, Amthor H, Marazzi G, Sassoon D. Loss of a single allele for Ku80 leads to progenitor dysfunction and accelerated aging in skeletal muscle. EMBO Mol Med 2012; 4:910-23. [PMID: 22915554 PMCID: PMC3491824 DOI: 10.1002/emmm.201101075] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 06/25/2012] [Accepted: 06/26/2012] [Indexed: 12/12/2022] Open
Abstract
Muscle wasting is a major cause of morbidity in the elderly. Ku80 is required for DNA double strand repair and is implicated in telomere maintenance. Complete loss-of-function leads to reduced post-natal growth and severe progeria in mice. We examined the role of Ku80 in age-related skeletal muscle atrophy. While complete loss of Ku80 leads to pronounced aging in muscle as expected, accompanied by accumulation of DNA damage, loss of a single allele is sufficient to accelerate aging in skeletal muscle although post-natal growth is normal. Ku80 heterozygous muscle shows no DNA damage accumulation but undergoes premature telomere shortening that alters stem cell self-renewal through stress response pathways including p53. These data reveal an unexpected requirement for both Ku80 alleles for optimal progenitor function and prevention of early onset aging in muscle, as well as providing a useful model for therapeutic approaches.
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Affiliation(s)
- Nathalie Didier
- Myology Group, UMR S INSERM, Université Pierre et Marie Curie Paris VI, Pitié-Salpétrière, Paris, France
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45
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Telomere maintenance genes SIRT1 and XRCC6 impact age-related decline in telomere length but only SIRT1 is associated with human longevity. Biogerontology 2011; 13:119-31. [PMID: 21972126 DOI: 10.1007/s10522-011-9360-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 09/20/2011] [Indexed: 12/20/2022]
Abstract
Leukocyte telomere length is widely considered a biomarker of human age and in many studies indicative of health or disease. We have obtained quantitative estimates of telomere length from blood leukocytes in a population sample, confirming results of previous studies that telomere length significantly decreases with age. Telomere length was also positively associated with several measures of healthy aging, but this relationship was dependent on age. We screened two genes known to be involved in telomere maintenance for association with the age-related decline in telomere length observed in our population to identify candidate longevity-associated genes. A single-nucleotide polymorphism located in the SIRT1 gene and another in the 3' flanking region of XRCC6 had significant effects on telomere length. At each bi-allelic locus, the minor variant was associated with longer telomeres, though the mode of inheritance fitting best differed between the two genes. No statistical interaction was detected for telomere length between the SIRT1 and XRCC6 variants or between these polymorphisms and age. The SIRT1 locus was significantly associated with longevity (P < 0.003). The frequency of the minor allele was higher in long-lived cases than in young controls, which coincides with the protective role of the minor variant for telomere length. In contrast, the XRCC6 variant was not associated with longevity. Furthermore, it did not affect the association of SIRT1 with exceptional survival. The association of the same variant of SIRT1 with longevity was near significant (P < 0.07) in a second population. These results suggest a potential role of SIRT1 in linking telomere length and longevity. Given the differences between this gene and XRCC6, they point to the distinct impact that alternate pathways of telomere maintenance may have on aging and exceptional survival.
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46
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Depletion of Ku70/80 reduces the levels of extrachromosomal telomeric circles and inhibits proliferation of ALT cells. Aging (Albany NY) 2011; 3:395-406. [PMID: 21512205 PMCID: PMC3117455 DOI: 10.18632/aging.100308] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In normal cells, telomeres shorten each time a cell divides ultimately resulting in cell senescence. In contrast, cancer cells counteract the loss of telomeric DNA either by inducing the expression of telomerase or by activating the alternative lengthening of telomeres (ALT) pathway. ALT cells are characterized by heterogeneous telomeres and the presence of extrachromosomal circular double-stranded DNA molecules containing telomeric repeat sequences. These telomeric circles (t-circles) are though to be generated through a recombination process and utilized as templates for telomere elongation by rolling-circle-replication, although their precise mechanism of formation and role in telomere maintenance and cell proliferation is largely unknown. Here we show that shRNA-mediated knockdown of the Ku70/80 heterodimer, a factor with functions at both pathological and natural DNA ends, inhibits ALT cell growth and results in a significant decrease in the levels of t-circles without affecting overall telomere length. These findings demonstrate that non homology-based processes contribute to the maintenance of t-circles and proliferation of ALT cells.
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47
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Rad51 and DNA-PKcs are involved in the generation of specific telomere aberrations induced by the quadruplex ligand 360A that impair mitotic cell progression and lead to cell death. Cell Mol Life Sci 2011; 69:629-40. [PMID: 21773671 PMCID: PMC3265728 DOI: 10.1007/s00018-011-0767-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 06/16/2011] [Accepted: 06/30/2011] [Indexed: 11/18/2022]
Abstract
Functional telomeres are protected from non-homologous end-joining (NHEJ) and homologous recombination (HR) DNA repair pathways. Replication is a critical period for telomeres because of the requirement for reconstitution of functional protected telomere conformations, a process that involves DNA repair proteins. Using knockdown of DNA-PKcs and Rad51 expression in three different cell lines, we demonstrate the respective involvement of NHEJ and HR in the formation of telomere aberrations induced by the G-quadruplex ligand 360A during or after replication. HR contributed to specific chromatid-type aberrations (telomere losses and doublets) affecting the lagging strand telomeres, whereas DNA-PKcs-dependent NHEJ was responsible for sister telomere fusions as a direct consequence of G-quadruplex formation and/or stabilization induced by 360A on parental telomere G strands. NHEJ and HR activation at telomeres altered mitotic progression in treated cells. In particular, NHEJ-mediated sister telomere fusions were associated with altered metaphase-anaphase transition and anaphase bridges and resulted in cell death during mitosis or early G1. Collectively, these data elucidate specific molecular and cellular mechanisms triggered by telomere targeting by the G-quadruplex ligand 360A, leading to cancer cell death.
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48
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Diotti R, Loayza D. Shelterin complex and associated factors at human telomeres. Nucleus 2011; 2:119-35. [PMID: 21738835 PMCID: PMC3127094 DOI: 10.4161/nucl.2.2.15135] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 02/09/2011] [Accepted: 02/11/2011] [Indexed: 12/17/2022] Open
Abstract
The processes regulating telomere function have major impacts on fundamental issues in human cancer biology. First, active telomere maintenance is almost always required for full oncogenic transformation of human cells, through cellular immortalization by endowment of an infinite replicative potential. Second, the attrition that telomeres undergo upon replication is responsible for the finite replicative life span of cells in culture, a process called senescence, which is of paramount importance for tumor suppression in vivo. The process of telomere-based senescence is intimately coupled to the induction of a DNA damage response emanating from telomeres, which can be elicited by both the ATM and ATR dependent pathways. At telomeres, the shelterin complex is constituted by a group of six proteins which assembles quantitatively along the telomere tract, and imparts both telomere maintenance and telomere protection. Shelterin is known to regulate the action of telomerase, and to prevent inappropriate DNA damage responses at chromosome ends, mostly through inhibition of ATM and ATR. The roles of shelterin have increasingly been associated with transient interactions with downstream factors that are not associated quantitatively or stably with telomeres. Here, some of the important known interactions between shelterin and these associated factors and their interplay to mediate telomere functions are reviewed.
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Affiliation(s)
- Raffaella Diotti
- Department of Biological Sciences, Hunter College, New York, NY, USA
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49
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Different DNA-PKcs functions in the repair of radiation-induced and spontaneous DSBs within interstitial telomeric sequences. Chromosoma 2011; 120:309-19. [PMID: 21359527 DOI: 10.1007/s00412-011-0313-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/03/2011] [Accepted: 02/03/2011] [Indexed: 10/18/2022]
Abstract
Interstitial telomeric sequences (ITSs) in hamster cells are hot spots for spontaneous and induced chromosome aberrations (CAs). Most data on ITS instability to date have been obtained in DNA repair-proficient cells. The classical non-homologous end joining repair pathway (C-NHEJ), which is the principal double strand break (DSB) repair mechanism in mammalian cells, is thought to restore the morphologically correct chromosome structure. The production of CAs thus involves DNA-PKcs-independent repair pathways. In our current study, we investigated the participation of DNA-PKcs from the C-NHEJ pathway in the repair of spontaneous or radiation-induced DSBs in ITSs using wild-type and DNA-PKcs mutant Chinese hamster ovary cells. Our data demonstrate that DNA-PKcs stabilizes spontaneous DSBs within ITSs from the chromosome 9 long arm, leading to the formation of terminal deletions. In addition, we show that DNA-PKcs-dependent C-NHEJ is employed following radiation-induced DSBs in other ITSs and restores morphologically correct chromosomes, whereas DNA-PKcs independent mechanisms co-exist in DNA-PKcs proficient cells leading to an excess of CAs within ITSs.
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50
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Li R, Yang Y, An Y, Zhou Y, Liu Y, Yu Q, Lu D, Wang H, Jin L, Zhou W, Qian J, Shugart YY. Genetic polymorphisms in DNA double-strand break repair genes XRCC5, XRCC6 and susceptibility to hepatocellular carcinoma. Carcinogenesis 2011; 32:530-6. [PMID: 21304054 DOI: 10.1093/carcin/bgr018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Environmental risk factors cause DNA damages. Imprecise DNA repair leads to chromosome aberrations, genome destabilization and hepatocarcinogenesis. Ku is a key DNA double-strand break repair protein. We hypothesized that the genetic variants in Ku subunits encoding genes, XRCC5/XRCC6, may contribute to hepatocellular carcinoma (HCC) susceptibility. We genotyped 13 common single nucleotide polymorphisms (SNPs) in XRCC5 and XRCC6 and evaluated their associations with HCC risk in 689 pathologically confirmed cases and 690 cancer-free controls from a Chinese population. We found that a significantly reduced risk for HCC was associated with XRCC5 rs16855458 [odds ratio (OR)=0.59; 95% confidence interval (CI)=0.43-0.81; CA+AA versus CC] and a significantly increased risk for HCC was associated with XRCC5 rs9288516 (OR=2.02; 95% CI=1.42-2.86; TA+AA versus TT) even after Bonferroni correction (Pcorrected=0.026 and 0.002, respectively). The effects of rs16855458 (OR=0.57; 95% CI=0.37-0.86, P=0.008) and rs9288516 (OR=1.86; 95% CI=1.19-2.90, P=0.007) were more significant in hepatitis B surface antigen-infected subjects than non-infected subjects. The haplotype-based analysis revealed that in XRCC5, AA in block 1 (OR=0.63; 95% CI=0.48-0.83) and CGGTT in block 2 (OR=0.52; 95% CI=0.39-0.69) were associated with decreased HCC risk (Pcorrected=0.013 and <0.001, respectively). The aforementioned two SNPs exhibited a significant cumulative risk effect (Ptrend<0.001). Additionally, potential interaction among XRCC5 rs9288516 and rs2267437, rs5751131 in XRCC6 was indicated by the multifactor dimensionality reduction analysis. In conclusion, XRCC5 variants may play a role in determining individual's HCC susceptibility, which warranted validation in larger studies.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 China
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