1
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Expression of DNA-damage response and repair genes after exposure to DNA-damaging agents in isogenic head and neck cells with altered radiosensitivity. Radiol Oncol 2022; 56:173-184. [PMID: 35390246 PMCID: PMC9122295 DOI: 10.2478/raon-2022-0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/16/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Increased radioresistance due to previous irradiation or radiosensitivity due to human papilloma virus (HPV) infection can be observed in head and neck squamous cell carcinoma (HNSCC). The DNA-damage response of cells after exposure to DNA-damaging agents plays a crucial role in determining the fate of exposed cells. Tightly regulated and interconnected signaling networks are activated to detect, signal the presence of and repair the DNA damage. Novel therapies targeting the DNA-damage response are emerging; however, an improved understanding of the complex signaling networks involved in tumor radioresistance and radiosensitivity is needed. MATERIALS AND METHODS In this study, we exposed isogenic human HNSCC cell lines with altered radiosensitivity to DNA-damaging agents: radiation, cisplatin and bleomycin. We investigated transcriptional alterations in the DNA-damage response by using a pathway-focused panel and reverse-transcription quantitative PCR. RESULTS In general, the isogenic cell lines with altered radiosensitivity significantly differed from one another in the expression of genes involved in the DNA-damage response. The radiosensitive (HPV-positive) cells showed overall decreases in the expression levels of the studied genes. In parental cells, upregulation of DNA-damage signaling and repair genes was observed following exposure to DNA-damaging agents, especially radiation. In contrast, radioresistant cells exhibited a distinct pattern of gene downregulation after exposure to cisplatin, whereas the levels in parental cells were unchanged. Exposure of radioresistant cells to bleomycin did not significantly affect the expression of DNA-damage signaling and repair genes. CONCLUSIONS Our analysis identified several possible targets: NBN, XRCC3, ATR, GADD45A and XPA. These putative targets should be studied and potentially exploited for sensibilization to ionizing radiation and/or cisplatin in HNSCC. The use of predesigned panels of DNA-damage signaling and repair genes proved to offer a convenient and quick approach to identify possible therapeutic targets.
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2
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Matos-Rodrigues GE, Martins RAP. An Eye in the Replication Stress Response: Lessons From Tissue-Specific Studies in vivo. Front Cell Dev Biol 2021; 9:731308. [PMID: 34805142 PMCID: PMC8599991 DOI: 10.3389/fcell.2021.731308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/21/2021] [Indexed: 11/29/2022] Open
Abstract
Several inherited human syndromes that severely affect organogenesis and other developmental processes are caused by mutations in replication stress response (RSR) genes. Although the molecular machinery of RSR is conserved, disease-causing mutations in RSR-genes may have distinct tissue-specific outcomes, indicating that progenitor cells may differ in their responses to RSR inactivation. Therefore, understanding how different cell types respond to replication stress is crucial to uncover the mechanisms of RSR-related human syndromes. Here, we review the ocular manifestations in RSR-related human syndromes and summarize recent findings investigating the mechanisms of RSR during eye development in vivo. We highlight a remarkable heterogeneity of progenitor cells responses to RSR inactivation and discuss its implications for RSR-related human syndromes.
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Affiliation(s)
- Gabriel E Matos-Rodrigues
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rodrigo A P Martins
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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3
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Novel FOXM1 inhibitor identified via gene network analysis induces autophagic FOXM1 degradation to overcome chemoresistance of human cancer cells. Cell Death Dis 2021; 12:704. [PMID: 34262016 PMCID: PMC8280155 DOI: 10.1038/s41419-021-03978-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 06/08/2021] [Accepted: 06/15/2021] [Indexed: 12/13/2022]
Abstract
FOXM1 transcription factor is an oncogene and a master regulator of chemoresistance in multiple cancers. Pharmacological inhibition of FOXM1 is a promising approach but has proven to be challenging. We performed a network-centric transcriptomic analysis to identify a novel compound STL427944 that selectively suppresses FOXM1 by inducing the relocalization of nuclear FOXM1 protein to the cytoplasm and promoting its subsequent degradation by autophagosomes. Human cancer cells treated with STL427944 exhibit increased sensitivity to cytotoxic effects of conventional chemotherapeutic treatments (platinum-based agents, 5-fluorouracil, and taxanes). RNA-seq analysis of STL427944-induced gene expression changes revealed prominent suppression of gene signatures characteristic for FOXM1 and its downstream targets but no significant changes in other important regulatory pathways, thereby suggesting high selectivity of STL427944 toward the FOXM1 pathway. Collectively, the novel autophagy-dependent mode of FOXM1 suppression by STL427944 validates a unique pathway to overcome tumor chemoresistance and improve the efficacy of treatment with conventional cancer drugs.
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4
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Cabañas Morafraile E, Pérez-Peña J, Fuentes-Antrás J, Manzano A, Pérez-Segura P, Pandiella A, Galán-Moya EM, Ocaña A. Genomic Correlates of DNA Damage in Breast Cancer Subtypes. Cancers (Basel) 2021; 13:cancers13092117. [PMID: 33925616 PMCID: PMC8123819 DOI: 10.3390/cancers13092117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/20/2021] [Accepted: 04/24/2021] [Indexed: 12/27/2022] Open
Abstract
Simple Summary Breast cancer (BC) is the most common invasive tumor in women and the second leading cause of cancer-related death. Therefore, identification of druggable targets to improve current therapies and overcome resistance is a major goal. In this work, we performed an in silico analysis of transcriptomic datasets in breast cancer, and focused on those involved in DNA damage, as were clearly upregulated using gene set enrichment analyses (GSEA), particular the following pathways: ATM/ATR, BARD1 and Fanconi Anemia. BHLHE40, RFWD2, BRIP1, PRKDC, NBN, RNF8, FANCD2, RAD1, BLM, DCLRE1C, UBE2T, CSTF1, MCM7, RFC4, YWHAB, YWHAZ, CDC6, CCNE1, and FANCI genes were amplified/overexpressed in BC, and correlated with detrimental prognosis. Finally, we selected the best transcriptomic signature of genes within this function that associated with clinical outcome to identify functional genomic correlates of outcome. Abstract Among the described druggable vulnerabilities, acting on the DNA repair mechanism has gained momentum, with the approval of PARP inhibitors in several indications, including breast cancer. However, beyond the mere presence of BRCA1/BRCA2 mutations, the identification of additional biomarkers that would help to select tumors with an extreme dependence on DNA repair machinery would help to stratify therapeutic decisions. Gene set enrichment analyses (GSEA) using public datasets evaluating expression values between normal breast tissue and breast cancer identified a set of upregulated genes. Genes included in different pathways, such as ATM/ATR, BARD1, and Fanconi Anemia, which are involved in the DNA damage response, were selected and confirmed using molecular alterations data contained at cBioportal. Nineteen genes from these gene sets were identified to be amplified and upregulated in breast cancer but only five of them NBN, PRKDC, RFWD2, UBE2T, and YWHAZ meet criteria in all breast cancer molecular subtypes. Correlation of the selected genes with prognosis (relapse free survival, RFS, and overall survival, OS) was performed using the KM Plotter Online Tool. In last place, we selected the best signature of genes within this process whose upregulation can be indicative of a more aggressive phenotype and linked with worse outcome. In summary, we identify genomic correlates within DNA damage pathway associated with prognosis in breast cancer.
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Affiliation(s)
- Esther Cabañas Morafraile
- Experimental Therapeutics Unit, Hospital Clínico San Carlos (HCSC), Instituto de Investigación Sanitaria San Carlos (IdISSC) and Centro de Investigación Biomédica en Red en Oncología (CIBERONC), 28040 Madrid, Spain; (E.C.M.); (J.F.-A.); (A.M.); (P.P.-S.)
| | - Javier Pérez-Peña
- Instituto de Biología Molecular y Celular del Cáncer del CSIC, IBSAL and CIBERONC, 37007 Salamanca, Spain; (J.P.-P.); (A.P.)
| | - Jesús Fuentes-Antrás
- Experimental Therapeutics Unit, Hospital Clínico San Carlos (HCSC), Instituto de Investigación Sanitaria San Carlos (IdISSC) and Centro de Investigación Biomédica en Red en Oncología (CIBERONC), 28040 Madrid, Spain; (E.C.M.); (J.F.-A.); (A.M.); (P.P.-S.)
| | - Aránzazu Manzano
- Experimental Therapeutics Unit, Hospital Clínico San Carlos (HCSC), Instituto de Investigación Sanitaria San Carlos (IdISSC) and Centro de Investigación Biomédica en Red en Oncología (CIBERONC), 28040 Madrid, Spain; (E.C.M.); (J.F.-A.); (A.M.); (P.P.-S.)
| | - Pedro Pérez-Segura
- Experimental Therapeutics Unit, Hospital Clínico San Carlos (HCSC), Instituto de Investigación Sanitaria San Carlos (IdISSC) and Centro de Investigación Biomédica en Red en Oncología (CIBERONC), 28040 Madrid, Spain; (E.C.M.); (J.F.-A.); (A.M.); (P.P.-S.)
| | - Atanasio Pandiella
- Instituto de Biología Molecular y Celular del Cáncer del CSIC, IBSAL and CIBERONC, 37007 Salamanca, Spain; (J.P.-P.); (A.P.)
| | - Eva M. Galán-Moya
- Translational Oncology Laboratory, Centro Regional de Investigaciones Biomédicas (CRIB) and Nursery School, Campus de Albacete, Universidad de Castilla-La Mancha, 02008 Albacete, Spain;
| | - Alberto Ocaña
- Experimental Therapeutics Unit, Hospital Clínico San Carlos (HCSC), Instituto de Investigación Sanitaria San Carlos (IdISSC) and Centro de Investigación Biomédica en Red en Oncología (CIBERONC), 28040 Madrid, Spain; (E.C.M.); (J.F.-A.); (A.M.); (P.P.-S.)
- Translational Oncology Laboratory, Centro Regional de Investigaciones Biomédicas (CRIB) and Nursery School, Campus de Albacete, Universidad de Castilla-La Mancha, 02008 Albacete, Spain;
- Correspondence:
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5
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Activation of DNA damage response signaling in mammalian cells by ionizing radiation. Free Radic Res 2021; 55:581-594. [PMID: 33455476 DOI: 10.1080/10715762.2021.1876853] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular responses to DNA damage are fundamental to preserve genomic integrity during various endogenous and exogenous stresses. Following radiation therapy and chemotherapy, this DNA damage response (DDR) also determines development of carcinogenesis and therapeutic outcome. In humans, DNA damage activates a robust network of signal transduction cascades, driven primarily through phosphorylation events. These responses primarily involve two key non-redundant signal transducing proteins of phosphatidylinositol 3-kinase-like (PIKK) family - ATR and ATM, and their downstream kinases (hChk1 and hChk2). They further phosphorylate effectors proteins such as p53, Cdc25A and Cdc25C which function either to activate the DNA damage checkpoints and cell death mechanisms, or DNA repair pathways. Identification of molecular pathways that determine signaling after DNA damage and trigger DNA repair in response to differing types of DNA lesions allows for a far better understanding of the consequences of radiation and chemotherapy on normal and tumor cells. Here we highlight the network of DNA damage response pathways that are activated after treatment with different types of radiation. Further, we discuss regulation of cell cycle checkpoint and DNA repair processes in the context of DDR in response to radiation.
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6
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The Replisome Mediates A-NHEJ Repair of Telomeres Lacking POT1-TPP1 Independently of MRN Function. Cell Rep 2019; 29:3708-3725.e5. [PMID: 31825846 PMCID: PMC7001145 DOI: 10.1016/j.celrep.2019.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 09/22/2019] [Accepted: 11/04/2019] [Indexed: 02/07/2023] Open
Abstract
Telomeres use shelterin to protect chromosome ends from activating the DNA damage sensor MRE11-RAD50-NBS1 (MRN), repressing ataxia-telangiectasia, mutated (ATM) and ATM and Rad3-related (ATR) dependent DNA damage checkpoint responses. The MRE11 nuclease is thought to be essential for the resection of the 5′ C-strand to generate the microhomologies necessary for alternative non-homologous end joining (A-NHEJ) repair. In the present study, we uncover DNA damage signaling and repair pathways engaged by components of the replisome complex to repair dysfunctional telomeres. In cells lacking MRN, single-stranded telomeric overhangs devoid of POT1-TPP1 do not recruit replication protein A (RPA), ATR-interacting protein (ATRIP), and RAD 51. Rather, components of the replisome complex, including Claspin, Proliferating cell nuclear antigen (PCNA), and Downstream neighbor of SON (DONSON), initiate DNA-PKcs-mediated p-CHK1 activation and A-NHEJ repair. In addition, Claspin directly interacts with TRF2 and recruits EXO1 to newly replicated telomeres to promote 5′ end resection. Our data indicate that MRN is dispensable for the repair of dysfunctional telomeres lacking POT1-TPP1 and highlight the contributions of the replisome in telomere repair. Rai et al. define roles for the DNA replisome components Claspin, PCNA, and DONSON in the sensing and repair of telomeres lacking POT1-TPP1. In cells lacking MRN, CPD initiates DNA-PKcs-mediated p-CHK1 activation and A-NHEJ repair. Claspin directly interacts with TRF2 and recruits EXO1 to promote 5′ C-strand end resection.
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7
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Formaldehyde inhibits UV-induced phosphorylation of histone H2AX. Toxicol In Vitro 2019; 61:104687. [PMID: 31614172 DOI: 10.1016/j.tiv.2019.104687] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/14/2019] [Accepted: 10/11/2019] [Indexed: 01/07/2023]
Abstract
Formaldehyde (FA) is widely known to cause DNA damage. Recently, our study showed that FA can also inhibit a repair process of DNA damage, nucleotide excision repair (NER). DNA damage response (DDR) involving activation of phosphorylation pathways is important for the accuracy of the repair process, and the inhibition of the accurate repair would raise mutation rate, leading to cancer. We herein investigated whether FA influences phosphorylation of histone H2AX (γ-H2AX), an intermediate player of DDR signaling pathways. Human keratinocytes HaCaT were treated with FA and then exposed to UV known to generate clear γ-H2AX signal. UV-induced γ-H2AX was inhibited by FA in a dose-dependent manner. The repair of pyrimidine dimers was inhibited by FA, while the recruitments of γ-H2AX-related proteins, Mre11 and 53BP1, to damaged sites were also delayed. Mre11, Nbs-1, H2AX and ATM were not degraded after treatment with FA as opposed to NER-related protein, TFIIH. On the other hand, FA inhibited phosphorylation of ATM which acts upstream of γ-H2AX. These results suggest that FA can affect the repair of DNA damage via inhibition of the phosphorylation pathways of H2AX.
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8
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Liu B, Lin L, Riazuddin S, Zubair A, Wang L, Di LJ, Li R, Dong TT, Deng CX, Tong WM. RETRACTED: PP2ACα deficiency impairs early cortical development through inducing DNA damage in neuroprojenitor cells. Int J Biochem Cell Biol 2019; 109:40-58. [PMID: 30710753 DOI: 10.1016/j.biocel.2019.01.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 01/09/2023]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor in Chief due to objections raised by persons identified as co-authors of corresponding author Bo Liu. The University of Macau states that Bo Liu is not affiliated with the University of Macau. The purported co-authors who are only affiliated with University of Macau report their names have been misappropriated for use on this paper without notice or prior permission. These co-authors deny any involvement in the study, preparation or submission of the manuscript, or review of any supporting data. The purported co-authors who are affiliated with the University of Maryland, Baltimore report their names and credentials have been misappropriated for use on this paper without notice or permission. These co-authors deny any involvement in the study, preparation or submission of the manuscript, or review of any supporting data. The National Institute of Health also states that none of the co-authors are affiliated with the institution. The University of Maryland, Baltimore states that Bo Liu is not affiliated with the university. Bo Liu has been non-responsive to approaches from the Publisher. Rui Li and Ting-Ting Dong were not reachable by the Publisher. Lin Lin confirmed the affiliation with The University of California Riverside; Chu-Xia Deng confirmed the affiliation with the University of Macau; Wei-Min Tong confirmed the affiliation with the Chinese Academy of Medical Sciences.
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Affiliation(s)
- Bo Liu
- Department of Otorhinolaryngology Head&Neck Surgery, University of Maryland School of Medicine, Baltimore, USA; University of Macau, Macau, China.
| | - Lin Lin
- University of Macau, Macau, China; Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Sciences. Beijing, China
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head&Neck Surgery, University of Maryland School of Medicine, Baltimore, USA
| | - Ahmed Zubair
- Department of Otorhinolaryngology Head&Neck Surgery, University of Maryland School of Medicine, Baltimore, USA
| | - Li Wang
- Branch of Cancer Research, Jones Hopkins University, Baltimore, USA
| | - Li-Jun Di
- Branch of Cancer Research, Jones Hopkins University, Baltimore, USA
| | - Rui Li
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Sciences. Beijing, China.
| | - Ting-Ting Dong
- Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Sciences. Beijing, China; China Agricultural University, Beijing, China
| | - Chu-Xia Deng
- National Institute of Neurological Disorders and Stroke, National Institute of Heath, Bethesda, USA.
| | - Wei-Min Tong
- National Institute of Neurological Disorders and Stroke, National Institute of Heath, Bethesda, USA.
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9
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Shibata A, Jeggo P. A historical reflection on our understanding of radiation-induced DNA double strand break repair in somatic mammalian cells; interfacing the past with the present. Int J Radiat Biol 2019; 95:945-956. [PMID: 30608893 DOI: 10.1080/09553002.2018.1564083] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Purpose: The International Journal of Radiation Biology (IJRB) is celebrating 60 years of publishing in 2019. IJRB has made an enormous contribution to publishing papers that have enhanced our understanding of the DNA damage response (DDR) activated following exposure to ionizing radiation (IR). The IR-induced DDR field has a rich history but many outstanding papers pass unread by young scientists overwhelmed by the current literature. We provide a historical reflection on key advances in the DDR field and interface them with current knowledge. Conclusions: DNA double strand breaks (DSBs) were identified as the major biological lesion induced by IR. But early studies on cells from IR-sensitive ataxia telangiectasia patients showed that DSB repair was not sufficient to prevent IR hypersensitivity. Subsequently, the ATM-dependent signal transduction process was revealed, with the breadth of the response being slowly unearthed. Early studies demonstrated at least two processes of DSB repair and revealed that mis-repair causes translocation formation. Recent studies, however, are unraveling more complexity in the repair process, including the specific processing of DSBs within transcriptionally active regions, and the significance of the chromatin environment. Despite the quality of these early and current studies, many questions remain to be addressed.
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Affiliation(s)
- Atsushi Shibata
- a Education and Research Support Center , Gunma University Graduate School of Medicine , Gunma , Maebashi , Japan
| | - Penny Jeggo
- b Genome Damage and Stability Centre, School of Life Sciences , University of Sussex , Brighton , UK
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10
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Chen MY, Hsu WC, Hsu SC, Yang YS, Chuang TH, Lin WJ, Tan TH, Su YW. PP4 deficiency leads to DNA replication stress that impairs immunoglobulin class switch efficiency. Cell Death Differ 2018; 26:1221-1234. [PMID: 30237510 PMCID: PMC6748143 DOI: 10.1038/s41418-018-0199-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/30/2018] [Accepted: 08/27/2018] [Indexed: 01/02/2023] Open
Abstract
The serine/threonine phosphatase PP4 has been implicated in DNA damage repair and cell cycle regulation through its dephosphorylation of specific substrates. We previously showed that PP4 is required for mouse B cell development, germinal center (GC) formation and immunoglobulin (Ig) class switch recombination (CSR). Here, we investigate the mechanisms underlying this requirement and demonstrate that murine PP4-deficient B lymphocytes have a defect in cell proliferation. Strikingly, the DNA damage response pathway that involves ATM/p53 and is linked to cell cycle arrest and impaired cell survival is strongly induced in these mutant B cells. In response to LPS + IL-4, stimuli that trigger IgG1 production, these PP4-deficient B cells show inefficient phosphorylation of ATR, leading to reduced retention of γH2AX-NBS1 complexes at sites of DNA damage, and compromised switching to IgG1. However, beyond the cell proliferation phase, conditional deletion of PP4 under the control of AID/cre completely restores normal IgG1 production in mutant B cell cultures. In vivo, co-deletion of PP4 and p53 by AID/cre partially rescues switching to IgG1 in B cells of mice immunized with TNP-KLH. Our findings establish that PP4 is indispensable for preventing DNA replication stress that could interfere with CSR, thereby promoting antibody switching during the humoral immune response.
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Affiliation(s)
- Ming-Yu Chen
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan
| | - Wei-Chan Hsu
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan
| | - Shu-Ching Hsu
- National Institute of Infectious Diseases and Vaccinology, NHRI, Zhunan, Miaoli County, Taiwan.,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research and Development, Chang Bing Show Chwan Memorial Hospital, Chang Hua, Taiwan
| | - Yu-Shao Yang
- National Institute of Infectious Diseases and Vaccinology, NHRI, Zhunan, Miaoli County, Taiwan
| | - Tsung-Hsien Chuang
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan
| | - Wen-Jye Lin
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan
| | - Tse-Hua Tan
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Yu-Wen Su
- Immunology Research Center, National Health Research Institutes (NHRI), Zhunan, Miaoli County, Taiwan.
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11
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Abstract
Proper regulation of the immune system is required for protection against pathogens and preventing autoimmune disorders. Inborn errors of the immune system due to inherited or de novo germline mutations can lead to the loss of protective immunity, aberrant immune homeostasis, and the development of autoimmune disease, or combinations of these. Forward genetic screens involving clinical material from patients with primary immunodeficiencies (PIDs) can vary in severity from life-threatening disease affecting multiple cell types and organs to relatively mild disease with susceptibility to a limited range of pathogens or mild autoimmune conditions. As central mediators of innate and adaptive immune responses, T cells are critical orchestrators and effectors of the immune response. As such, several PIDs result from loss of or altered T cell function. PID-associated functional defects range from complete absence of T cell development to uncontrolled effector cell activation. Furthermore, the gene products of known PID causal genes are involved in diverse molecular pathways ranging from T cell receptor signaling to regulators of protein glycosylation. Identification of the molecular and biochemical cause of PIDs can not only guide the course of treatment for patients, but also inform our understanding of the basic biology behind T cell function. In this chapter, we review PIDs with known genetic causes that intrinsically affect T cell function with particular focus on perturbations of biochemical pathways.
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Affiliation(s)
- William A Comrie
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States; Clinical Genomics Program, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, United States
| | - Michael J Lenardo
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States; Clinical Genomics Program, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, United States.
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12
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Pérez-Alea M, Vivancos A, Caratú G, Matito J, Ferrer B, Hernandez-Losa J, Cortés J, Muñoz E, Garcia-Patos V, Recio JA. Genetic profile of GNAQ-mutated blue melanocytic neoplasms reveals mutations in genes linked to genomic instability and the PI3K pathway. Oncotarget 2018; 7:28086-95. [PMID: 27057633 PMCID: PMC5053711 DOI: 10.18632/oncotarget.8578] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/28/2016] [Indexed: 12/20/2022] Open
Abstract
Melanomas arising in association with a common or cellular blue nevus (MABN) comprise a relatively rare and heterogeneous group of lethal melanomas. Although GNAQ is known to be frequently mutated in common blue nevus, cellular blue nevus (CBN) and MABN and these malignant lesions present gross chromosome alterations harboring BAP1 mutations, little is known about other mutations that contribute to the development and progression of these neoplasms. Thus, the genetic profile of these tumors is important to increase the number of intervention and treatment modalities. Here, we characterized and genetically profiled two different sections of a rare MABN and two CBNs from three different patients. All of the samples harbored a GNAQ mutation, exhibited RAS pathway activation, and harbored additional mutations in genes associated with genomic instability and epigenetic regulation (KMT2C, FANCD2, ATR, ATRX, NBN, ERCC2, SETD2, and WHSC1). In addition, all neoplasms harbored mutations that directly or indirectly affected either the regulation or activation of the PI3K pathway (PIK3CA, NF1, INPP5B and GSK3B). Our results not only help understand the genetic complexity of these blue melanocytic lesions but provide a rationale to use the combination of PI3K/MTOR and MEK1/2 inhibitors against these types of tumors.
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Affiliation(s)
- Mileidys Pérez-Alea
- Biomedical Research in Melanoma-Animal Models and Cancer Laboratory, Oncology Program, Vall d'Hebron Research institute, VHIR-Vall d'Hebron Hospital, Barcelona-UAB 08035, Barcelona, Spain
| | - Ana Vivancos
- Cancer Genomics Group Translational Research Program, Vall d'Hebron Institute of Oncology-VHIO, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Ginevra Caratú
- Cancer Genomics Group Translational Research Program, Vall d'Hebron Institute of Oncology-VHIO, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Judit Matito
- Cancer Genomics Group Translational Research Program, Vall d'Hebron Institute of Oncology-VHIO, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Berta Ferrer
- Biomedical Research in Melanoma-Animal Models and Cancer Laboratory, Oncology Program, Vall d'Hebron Research institute, VHIR-Vall d'Hebron Hospital, Barcelona-UAB 08035, Barcelona, Spain.,Anatomy Pathology Department, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Javier Hernandez-Losa
- Anatomy Pathology Department, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Javier Cortés
- Clinical Oncology Program, Vall d'Hebron Institute of Oncology-VHIO, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Eva Muñoz
- Biomedical Research in Melanoma-Animal Models and Cancer Laboratory, Oncology Program, Vall d'Hebron Research institute, VHIR-Vall d'Hebron Hospital, Barcelona-UAB 08035, Barcelona, Spain.,Clinical Oncology Program, Vall d'Hebron Institute of Oncology-VHIO, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Vicente Garcia-Patos
- Biomedical Research in Melanoma-Animal Models and Cancer Laboratory, Oncology Program, Vall d'Hebron Research institute, VHIR-Vall d'Hebron Hospital, Barcelona-UAB 08035, Barcelona, Spain.,Dermatology Department, Vall d'Hebron Hospital, Barcelona-UAB, Barcelona 08035, Spain
| | - Juan A Recio
- Biomedical Research in Melanoma-Animal Models and Cancer Laboratory, Oncology Program, Vall d'Hebron Research institute, VHIR-Vall d'Hebron Hospital, Barcelona-UAB 08035, Barcelona, Spain
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13
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Yao S, Fan LYN, Lam EWF. The FOXO3-FOXM1 axis: A key cancer drug target and a modulator of cancer drug resistance. Semin Cancer Biol 2017; 50:77-89. [PMID: 29180117 PMCID: PMC6565931 DOI: 10.1016/j.semcancer.2017.11.018] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/30/2017] [Accepted: 11/23/2017] [Indexed: 12/11/2022]
Abstract
The FOXO3 and FOXM1 forkhead box transcription factors, functioning downstream of the essential PI3K-Akt, Ras-ERK and JNK/p38MAPK signalling cascades, are crucial for cell proliferation, differentiation, cell survival, senescence, DNA damage repair and cell cycle control. The development of resistance to both conventional and newly emerged molecularly targeted therapies is a major challenge confronting current cancer treatment in the clinic. Intriguingly, the mechanisms of resistance to ‘classical’ cytotoxic chemotherapeutics and to molecularly targeted therapies are invariably linked to deregulated signalling through the FOXO3 and FOXM1 transcription factors. This is owing to the involvement of FOXO3 and FOXM1 in the regulation of genes linked to crucial drug action-related cellular processes, including stem cell renewal, DNA repair, cell survival, drug efflux, and deregulated mitosis. A better understanding of the mechanisms regulating the FOXO3-FOXM1 axis, as well as their downstream transcriptional targets and functions, may render these proteins reliable and early diagnostic/prognostic factors as well as crucial therapeutic targets for cancer treatment and importantly, for overcoming chemotherapeutic drug resistance.
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Affiliation(s)
- Shang Yao
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Lavender Yuen-Nam Fan
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Eric Wing-Fai Lam
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK.
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14
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Gadducci A, Guerrieri ME. PARP inhibitors alone and in combination with other biological agents in homologous recombination deficient epithelial ovarian cancer: From the basic research to the clinic. Crit Rev Oncol Hematol 2017; 114:153-165. [PMID: 28477743 DOI: 10.1016/j.critrevonc.2017.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/15/2017] [Accepted: 04/11/2017] [Indexed: 12/21/2022] Open
Abstract
Hereditary epithelial ovarian cancer [EOC] in germline BRCA mutation (gBRCAm) carriers has a distinct clinical behavior characterized by younger age, high- grade serous histology, advanced stage, visceral distribution of disease, high response to platinum and other non-platinum agents and better clinical outcome. Sporadic EOC with homologous recombination deficiency [HDR] but no gBRCAm has the same biological and clinical behavior as EOC in gBRCAm carriers ("BRCAness"phenotype). Biomarkers are in development to enable an accurate definition of molecular features of BRCAness phenotype, and trials are warranted to determine whether such HDR signature will predict sensitivity to PARP inhibitors in sporadic EOC. Moreover, the link between PARP inhibition and angiogenesis suppression, the immunologic properties of EOC in gBRCAm carriers, the HRD induced by PI3K inhibition in EOC cells in vitro strongly support novel clinical trials testing the combination of PARP inhibitors with other biological agents.
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Affiliation(s)
- Angiolo Gadducci
- Department of Clinical and Experimental Medicine, Division of Gynecology and Obstetrics, University of Pisa, Italy.
| | - Maria Elena Guerrieri
- Department of Clinical and Experimental Medicine, Division of Gynecology and Obstetrics, University of Pisa, Italy
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15
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Balestrini A, Nicolas L, Yang-Lott K, Guryanova OA, Levine RL, Bassing CH, Chaudhuri J, Petrini JHJ. Defining ATM-Independent Functions of the Mre11 Complex with a Novel Mouse Model. Mol Cancer Res 2015; 14:185-95. [PMID: 26538284 DOI: 10.1158/1541-7786.mcr-15-0281] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/25/2015] [Indexed: 01/09/2023]
Abstract
UNLABELLED The Mre11 complex (Mre11, Rad50, and Nbs1) occupies a central node of the DNA damage response (DDR) network and is required for ATM activation in response to DNA damage. Hypomorphic alleles of MRE11 and NBS1 confer embryonic lethality in ATM-deficient mice, indicating that the complex exerts ATM-independent functions that are essential when ATM is absent. To delineate those functions, a conditional ATM allele (ATM(flox)) was crossed to hypomorphic NBS1 mutants (Nbs1(ΔB/ΔB) mice). Nbs1(ΔB/ΔB) Atm(-/-) hematopoietic cells derived by crossing to vav(cre) were viable in vivo. Nbs1(ΔB/ΔB) Atm(-/-) (VAV) mice exhibited a pronounced defect in double-strand break repair and completely penetrant early onset lymphomagenesis. In addition to repair defects observed, fragile site instability was noted, indicating that the Mre11 complex promotes genome stability upon replication stress in vivo. The data suggest combined influences of the Mre11 complex on DNA repair, as well as the responses to DNA damage and DNA replication stress. IMPLICATIONS A novel mouse model was developed, by combining a vav(cre)-inducible ATM knockout mouse with an NBS1 hypomorphic mutation, to analyze ATM-independent functions of the Mre11 complex in vivo. These data show that the DNA repair, rather than DDR signaling functions of the complex, is acutely required in the context of ATM deficiency to suppress genome instability and lymphomagenesis.
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Affiliation(s)
- Alessia Balestrini
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York
| | - Laura Nicolas
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Katherine Yang-Lott
- Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Olga A Guryanova
- Human Oncology and Pathogenesis Program, Leukemia Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Leukemia Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Craig H Bassing
- Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - John H J Petrini
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York.
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16
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Lavin MF, Kozlov S, Gatei M, Kijas AW. ATM-Dependent Phosphorylation of All Three Members of the MRN Complex: From Sensor to Adaptor. Biomolecules 2015; 5:2877-902. [PMID: 26512707 PMCID: PMC4693261 DOI: 10.3390/biom5042877] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 11/16/2022] Open
Abstract
The recognition, signalling and repair of DNA double strand breaks (DSB) involves the participation of a multitude of proteins and post-translational events that ensure maintenance of genome integrity. Amongst the proteins involved are several which when mutated give rise to genetic disorders characterised by chromosomal abnormalities, cancer predisposition, neurodegeneration and other pathologies. ATM (mutated in ataxia-telangiectasia (A-T) and members of the Mre11/Rad50/Nbs1 (MRN complex) play key roles in this process. The MRN complex rapidly recognises and locates to DNA DSB where it acts to recruit and assist in ATM activation. ATM, in the company of several other DNA damage response proteins, in turn phosphorylates all three members of the MRN complex to initiate downstream signalling. While ATM has hundreds of substrates, members of the MRN complex play a pivotal role in mediating the downstream signalling events that give rise to cell cycle control, DNA repair and ultimately cell survival or apoptosis. Here we focus on the interplay between ATM and the MRN complex in initiating signaling of breaks and more specifically on the adaptor role of the MRN complex in mediating ATM signalling to downstream substrates to control different cellular processes.
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Affiliation(s)
- Martin F Lavin
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Sergei Kozlov
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Magtouf Gatei
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
| | - Amanda W Kijas
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia.
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17
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Gurung RL, Lim SN, Low GKM, Hande MP. MST-312 Alters Telomere Dynamics, Gene Expression Profiles and Growth in Human Breast Cancer Cells. JOURNAL OF NUTRIGENETICS AND NUTRIGENOMICS 2015; 7:283-98. [PMID: 26022559 DOI: 10.1159/000381346] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Targeting telomerase is a potential cancer management strategy given that it allows unlimited cellular replication in the majority of cancers. Dysfunctional telomeres are recognized as double-strand breaks. However, the status of DNA repair response pathways following telomerase inhibition is not well understood in human breast cancer cells. Here, we evaluated the effects of MST-312, a chemically modified derivative from tea catechin, epigallocatechin gallate, on telomere dynamics and DNA damage gene expression in breast cancer cells. METHODOLOGY Breast cancer cells MCF-7 and MDA-MB-231 were treated with MST-312, and telomere-telomerase homeostasis, induced DNA damage and gene expression profiling were analyzed. RESULTS MST-312 decreased telomerase activity and induced telomere dysfunction and growth arrest in breast cancer cells with more profound effects in MDA-MB-231 than in MCF-7 cells. Consistent with these data, the telomere-protective protein TRF2 was downregulated in MDA-MB-231 cells. MST-312 induced DNA damage at telomeres accompanied by reduced expression of DNA damage-related genes ATM and RAD50. Co-treatment with MST-312 and the poly(ADP-ribose) polymerase 1 (PARP-1) inhibitor PJ-34 further enhanced growth reduction as compared to single treatment with MST-312 or PJ-34. CONCLUSIONS Our work demonstrates potential importance for the establishment of antitelomerase cancer therapy using MST-312 along with PARP-1 inhibition in breast cancer therapy.
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Affiliation(s)
- Resham Lal Gurung
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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18
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Kar A, Kaur M, Ghosh T, Khan MM, Sharma A, Shekhar R, Varshney A, Saxena S. RPA70 depletion induces hSSB1/2-INTS3 complex to initiate ATR signaling. Nucleic Acids Res 2015; 43:4962-74. [PMID: 25916848 PMCID: PMC4446429 DOI: 10.1093/nar/gkv369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/08/2015] [Indexed: 01/12/2023] Open
Abstract
The primary eukaryotic single-stranded DNA-binding protein, Replication protein A (RPA), binds to single-stranded DNA at the sites of DNA damage and recruits the apical checkpoint kinase, ATR via its partner protein, ATRIP. It has been demonstrated that absence of RPA incapacitates the ATR-mediated checkpoint response. We report that in the absence of RPA, human single-stranded DNA-binding protein 1 (hSSB1) and its partner protein INTS3 form sub-nuclear foci, associate with the ATR-ATRIP complex and recruit it to the sites of genomic stress. The ATRIP foci formed after RPA depletion are abrogated in the absence of INTS3, establishing that hSSB-INTS3 complex recruits the ATR-ATRIP checkpoint complex to the sites of genomic stress. Depletion of homologs hSSB1/2 and INTS3 in RPA-deficient cells attenuates Chk1 phosphorylation, indicating that the cells are debilitated in responding to stress. We have identified that TopBP1 and the Rad9-Rad1-Hus1 complex are essential for the alternate mode of ATR activation. In summation, we report that the single-stranded DNA-binding protein complex, hSSB1/2-INTS3 can recruit the checkpoint complex to initiate ATR signaling.
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Affiliation(s)
- Ananya Kar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Manpreet Kaur
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Tanushree Ghosh
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Md Muntaz Khan
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Aparna Sharma
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Ritu Shekhar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Akhil Varshney
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Sandeep Saxena
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
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19
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Interdependence of the rad50 hook and globular domain functions. Mol Cell 2015; 57:479-91. [PMID: 25601756 DOI: 10.1016/j.molcel.2014.12.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/27/2014] [Accepted: 12/08/2014] [Indexed: 11/24/2022]
Abstract
Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions.
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20
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Saito Y, Zhou H, Kobayashi J. Chromatin modification and NBS1: their relationship in DNA double-strand break repair. Genes Genet Syst 2015; 90:195-208. [DOI: 10.1266/ggs.15-00010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Yuichiro Saito
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University
| | - Hui Zhou
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University
| | - Junya Kobayashi
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University
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21
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The MRE11 complex: An important source of stress relief. Exp Cell Res 2014; 329:162-9. [DOI: 10.1016/j.yexcr.2014.10.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/01/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
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22
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Gatei M, Kijas AW, Biard D, Dörk T, Lavin MF. RAD50 phosphorylation promotes ATR downstream signaling and DNA restart following replication stress. Hum Mol Genet 2014; 23:4232-48. [PMID: 24694934 DOI: 10.1093/hmg/ddu141] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The MRE11/RAD50/NBN (MRN) complex plays a key role in detecting DNA double-strand breaks, recruiting and activating ataxia-telangiectasia mutated and in processing the breaks. Members of this complex also act as adaptor molecules for downstream signaling to the cell cycle and other cellular processes. Somewhat more controversial are the results to support a role for MRN in the ataxia-telangiectasia and Rad3-related (ATR) activation and signaling. We provide evidence that RAD50 is required for ATR activation in mammalian cells in response to DNA replication stress. It is in turn phosphorylated at a specific site (S635) by ATR, which is required for ATR signaling through Chk1 and other downstream substrates. We find that RAD50 phosphorylation is essential for DNA replication restart by promoting loading of cohesin at these sites. We also demonstrate that replication stress-induced RAD50 phosphorylation is functionally significant for cell survival and cell cycle checkpoint activation. These results highlight the importance of the adaptor role for a member of the MRN complex in all aspects of the response to DNA replication stress.
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Affiliation(s)
- Magtouf Gatei
- Radiation Biology and Oncology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia
| | - Amanda W Kijas
- Radiation Biology and Oncology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia
| | - Denis Biard
- CEA, DSV/iMETI/SEPIA; BP6, 92265 Fontenay-aux-Roses Cedex, France
| | - Thilo Dörk
- Clinics of Obstetrics and Gynaecology, Hannover Medical School, Gynaecology Research Unit, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany and
| | - Martin F Lavin
- Radiation Biology and Oncology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia Centre for Clinical Research, University of Queensland, Building 71/918, Royal Brisbane & Women's Hospital Campus, Herston, QLD 4029, Australia
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23
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Liu B, Chen X, Wang ZQ, Tong WM. Nbn gene inactivation in the CNS of mouse inhibits the myelinating ability of the mature cortical oligodendrocytes. Glia 2014; 62:133-44. [PMID: 24272708 DOI: 10.1002/glia.22593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/07/2013] [Accepted: 10/17/2013] [Indexed: 01/12/2023]
Abstract
Nijmegen Breakage Syndrome (NBS) is a recessive genetic disorder characterized by immunodeficiency, elevated sensitivity to ionizing radiation, chromosomal instability, microcephaly, and high predisposition to malignancies. Since the underlying molecular mechanisms of the NBS microcephaly are still obscure, thus our group previously inactivated the Nbn gene in the central nervous system (CNS) of mice by nestin-Cre targeting gene system, and generated Nbn(CNS-del) mice. Interestingly, the newborn Nbn(CNS-del) mice exhibit obvious microcephaly, which is accompanied by severe ataxia and balance deficiency. In this study presented here, we report that Nbn-deficiency induces the enhanced apoptosis of the mature oligodendrocytes at postnatal day 7, which further affects the myelination of the nerve fibers of cerebrum and corpus callosum.The distinct regulatory roles of Ataxia telangiectasia mutated (ATM) signaling and protein kinase B(Akt)/the mammalian target of Rapamycin (AKT/mTOR) signaling are responsible for the enhanced apoptosis of the Nbn-deficient oligodendrocytes. In addition, a series of transcriptional factors including histonedeacetylase (HDAC), zinc finger protein 191 (ZFP-191) and myelin sheath regulatory factor (MRF) play distinct roles in regulating the myelination of the Nbn-deficient oligodendrocytes. Based on these results, it concludes that ATM-Chk2-P53-P21 signaling pathway and the AKT/mTOR signaling pathway are both responsible for the enhanced apoptosis of the Nbn-deficient oligodendrocytes. HDAC, ZFP-191, and MRF are also involved in the pathogenesis of the hypomyelination of the Nbn-deficient oligodendrocytes.
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Affiliation(s)
- Bo Liu
- Department of Pathology, Center for Experimental Animal Research, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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24
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Wu CS, Ouyang J, Mori E, Nguyen HD, Maréchal A, Hallet A, Chen DJ, Zou L. SUMOylation of ATRIP potentiates DNA damage signaling by boosting multiple protein interactions in the ATR pathway. Genes Dev 2014; 28:1472-84. [PMID: 24990965 PMCID: PMC4083090 DOI: 10.1101/gad.238535.114] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 06/02/2014] [Indexed: 12/21/2022]
Abstract
The ATR (ATM [ataxia telangiectasia-mutated]- and Rad3-related) checkpoint is a crucial DNA damage signaling pathway. While the ATR pathway is known to transmit DNA damage signals through the ATR-Chk1 kinase cascade, whether post-translational modifications other than phosphorylation are important for this pathway remains largely unknown. Here, we show that protein SUMOylation plays a key role in the ATR pathway. ATRIP, the regulatory partner of ATR, is modified by SUMO2/3 at K234 and K289. An ATRIP mutant lacking the SUMOylation sites fails to localize to DNA damage and support ATR activation efficiently. Surprisingly, the ATRIP SUMOylation mutant is compromised in the interaction with a protein group, rather than a single protein, in the ATR pathway. Multiple ATRIP-interacting proteins, including ATR, RPA70, TopBP1, and the MRE11-RAD50-NBS1 complex, exhibit reduced binding to the ATRIP SUMOylation mutant in cells and display affinity for SUMO2 chains in vitro, suggesting that they bind not only ATRIP but also SUMO. Fusion of a SUMO2 chain to the ATRIP SUMOylation mutant enhances its interaction with the protein group and partially suppresses its localization and functional defects, revealing that ATRIP SUMOylation promotes ATR activation by providing a unique type of protein glue that boosts multiple protein interactions along the ATR pathway.
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Affiliation(s)
- Ching-Shyi Wu
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Eiichiro Mori
- Division of Molecular Radiation Biology, Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Hai Dang Nguyen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Alexandre Maréchal
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Alexander Hallet
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - David J. Chen
- Division of Molecular Radiation Biology, Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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25
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Grundy GJ, Moulding HA, Caldecott KW, Rulten SL. One ring to bring them all--the role of Ku in mammalian non-homologous end joining. DNA Repair (Amst) 2014; 17:30-8. [PMID: 24680220 DOI: 10.1016/j.dnarep.2014.02.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 02/25/2014] [Indexed: 12/26/2022]
Abstract
The repair of DNA double strand breaks is essential for cell survival and several conserved pathways have evolved to ensure their rapid and efficient repair. The non-homologous end joining pathway is initiated when Ku binds to the DNA break site. Ku is an abundant nuclear heterodimer of Ku70 and Ku80 with a toroidal structure that allows the protein to slide over the broken DNA end and bind with high affinity. Once locked into placed, Ku acts as a tool-belt to recruit multiple interacting proteins, forming one or more non-homologous end joining complexes that act in a regulated manner to ensure efficient repair of DNA ends. Here we review the structure and functions of Ku and the proteins with which it interacts during non-homologous end joining.
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Affiliation(s)
- Gabrielle J Grundy
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
| | - Hayley A Moulding
- School of Biochemistry, Medical Sciences, University Walk, Bristol BS8 1TD, UK
| | - Keith W Caldecott
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
| | - Stuart L Rulten
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
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26
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Roset R, Inagaki A, Hohl M, Brenet F, Lafrance-Vanasse J, Lange J, Scandura JM, Tainer JA, Keeney S, Petrini JH. The Rad50 hook domain regulates DNA damage signaling and tumorigenesis. Genes Dev 2014; 28:451-62. [PMID: 24532689 PMCID: PMC3950343 DOI: 10.1101/gad.236745.113] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/16/2014] [Indexed: 01/25/2023]
Abstract
The Mre11 complex (Mre11, Rad50, and Nbs1) is a central component of the DNA damage response (DDR), governing both double-strand break repair and DDR signaling. Rad50 contains a highly conserved Zn(2+)-dependent homodimerization interface, the Rad50 hook domain. Mutations that inactivate the hook domain produce a null phenotype. In this study, we analyzed mutants with reduced hook domain function in an effort to stratify hook-dependent Mre11 complex functions. One of these alleles, Rad50(46), conferred reduced Zn(2+) affinity and dimerization efficiency. Homozygous Rad50(46/46) mutations were lethal in mice. However, in the presence of wild-type Rad50, Rad50(46) exerted a dominant gain-of-function phenotype associated with chronic DDR signaling. At the organismal level, Rad50(+/46) exhibited hydrocephalus, liver tumorigenesis, and defects in primitive hematopoietic and gametogenic cells. These outcomes were dependent on ATM, as all phenotypes were mitigated in Rad50(+/46) Atm(+/-) mice. These data reveal that the murine Rad50 hook domain strongly influences Mre11 complex-dependent DDR signaling, tissue homeostasis, and tumorigenesis.
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Affiliation(s)
- Ramon Roset
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
| | - Akiko Inagaki
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
| | - Marcel Hohl
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
| | - Fabienne Brenet
- Department of Medicine, Laboratory of Molecular Hematopoiesis, Weill-Cornell Medical College, New York, New York 10065, USA
| | - Julien Lafrance-Vanasse
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Julian Lange
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
| | - Joseph M. Scandura
- Department of Medicine, Laboratory of Molecular Hematopoiesis, Weill-Cornell Medical College, New York, New York 10065, USA
| | - John A. Tainer
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
- Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
- Weill Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA
| | - John H.J. Petrini
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
- Weill Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA
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27
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The ATM-mediated DNA-damage response. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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28
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Liu B, Chen X, Wang ZQ, Tong WM. DNA damage and oxidative injury are associated with hypomyelination in the corpus callosum of newborn Nbn(CNS-del) mice. J Neurosci Res 2013; 92:254-66. [PMID: 24272991 DOI: 10.1002/jnr.23313] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 09/10/2013] [Accepted: 09/18/2013] [Indexed: 01/16/2023]
Abstract
Nijmegen breakage syndrome (NBS), caused by mutation of the Nbn gene, is a recessive genetic disorder characterized by immunodeficiency, elevated sensitivity to ionizing radiation, chromosomal instability, microcephaly, and high predisposition to malignancies. To explore the underlying molecular mechanisms of NBS microcephaly, Frappart et al. previously inactivated Nbn gene in the central nervous system (CNS) of mice by the nestin-Cre targeting gene system and generated Nbn(CNS-del) mice. Here we first report that Nbn gene inactivation induces the defective proliferation and enhanced apoptosis of the oligodendrocyte precursor cells (OPCs), contributing to the severe hypomyelination of the nerve fibers of the corpus callosum. Under conditions of DNA damage and oxidative stress, the distinct regulatory roles of ATM-Chk2 signaling and AKT/mTOR signaling are responsible for the defective proliferation and enhanced apoptosis of the Nbn-deficient OPCs. In addition, specific HDAC isoforms may play distinctive roles in regulating the myelination of the Nbn-deficient OPCs. However, brain-derived neurotrophic factor and nerve growth factor stimulation attenuates the oxidative stress and thereby increases the proliferation of the Nbn-deficient OPCs, which is accompanied by upregulation of the AKT/mTOR/P70S6K signaling pathway. Taken together, these findings demonstrate that DNA damage and oxidative stress resulting from Nbn gene inactivation are associated with hypomyelination of the nerve fibers of corpus callosum.
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Affiliation(s)
- B Liu
- Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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29
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FOXM1 targets NBS1 to regulate DNA damage-induced senescence and epirubicin resistance. Oncogene 2013; 33:4144-55. [PMID: 24141789 PMCID: PMC3969838 DOI: 10.1038/onc.2013.457] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/09/2013] [Accepted: 09/16/2013] [Indexed: 12/25/2022]
Abstract
FOXM1 is implicated in genotoxic drug resistance but its mechanism of action remains elusive. We show here that FOXM1-depletion can sensitize breast cancer cells and MEFs into entering epirubicin-induced senescence, with the loss of long-term cell proliferation ability, the accumulation of γH2AX foci, and the induction of senescence-associated β-galactosidase activity and cell morphology. Conversely, reconstitution of FOXM1 in FOXM1-deficient MEFs alleviates the accumulation of senescence-associated γH2AX foci. We also demonstrate that FOXM1 regulates NBS1 at the transcriptional level through an FHRE on its promoter. Like FOXM1, NBS1 is overexpressed in the epirubicin-resistant MCF-7EpiR cells and its expression level is low but inducible by epirubicin in MCF-7 cells. Consistently, overexpression of FOXM1 augmented and FOXM1 depletion reduced NBS1 expression and epirubicin-induced ATM phosphorylation in breast cancer cells. Together these findings suggest that FOXM1 increases NBS1 expression and ATM phosphorylation, possibly through increasing the levels of the MRN(MRE11/RAD50/NBS1) complex. Consistent with this idea, the loss of P-ATM induction by epirubicin in the NBS1-deficient NBS1-LBI fibroblasts can be rescued by NBS1 reconstitution. Resembling FOXM1, NBS1 depletion also rendered MCF-7 and MCF-7EpiR cells more sensitive to epirubicin-induced cellular senescence. In agreement, the DNA repair-defective and senescence phenotypes in FOXM1-deficent cells can be effectively rescued by overexpression of NBS1. Moreover, overexpression of NBS1 and FOXM1 similarly enhanced and their depletion downregulated HR DNA repair activity. Crucially, overexpression of FOXM1 failed to augment HR activity in the background of NBS1 depletion, demonstrating that NBS1 is indispensable for the HR function of FOXM1. The physiological relevance of the regulation of NBS1 expression by FOXM1 is further underscored by the strong and significant correlation between nuclear FOXM1 and total NBS1 expression in breast cancer patient samples, further suggesting that NBS1 as a key FOXM1 target gene involved in DNA damage response, genotoxic drug resistance and DNA damage-induced senescence.
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30
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Rodrigues PMG, Grigaravicius P, Remus M, Cavalheiro GR, Gomes AL, Martins MR, Frappart L, Reuss D, McKinnon PJ, von Deimling A, Martins RAP, Frappart PO. Nbn and atm cooperate in a tissue and developmental stage-specific manner to prevent double strand breaks and apoptosis in developing brain and eye. PLoS One 2013; 8:e69209. [PMID: 23935957 PMCID: PMC3728324 DOI: 10.1371/journal.pone.0069209] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/06/2013] [Indexed: 01/30/2023] Open
Abstract
Nibrin (NBN or NBS1) and ATM are key factors for DNA Double Strand Break (DSB) signaling and repair. Mutations in NBN or ATM result in Nijmegen Breakage Syndrome and Ataxia telangiectasia. These syndromes share common features such as radiosensitivity, neurological developmental defects and cancer predisposition. However, the functional synergy of Nbn and Atm in different tissues and developmental stages is not yet understood. Here, we show in vivo consequences of conditional inactivation of both genes in neural stem/progenitor cells using Nestin-Cre mice. Genetic inactivation of Atm in the central nervous system of Nbn-deficient mice led to reduced life span and increased DSBs, resulting in increased apoptosis during neural development. Surprisingly, the increase of DSBs and apoptosis was found only in few tissues including cerebellum, ganglionic eminences and lens. In sharp contrast, we showed that apoptosis associated with Nbn deletion was prevented by simultaneous inactivation of Atm in developing retina. Therefore, we propose that Nbn and Atm collaborate to prevent DSB accumulation and apoptosis during development in a tissue- and developmental stage-specific manner.
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Affiliation(s)
- Paulo M. G. Rodrigues
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paulius Grigaravicius
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martina Remus
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Gabriel R. Cavalheiro
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anielle L. Gomes
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mauricio R. Martins
- Programa de Pós Graduação em Biofísica, IBCCF, Universidade Federal do Rio de Janeiro, CCS, Rio de Janeiro, Brazil
| | - Lucien Frappart
- Leibniz Institute for Age Research – Fritz Lipmann Institute (FLI), Jena, Germany
| | - David Reuss
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Peter J. McKinnon
- Department of Genetics, St.Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Andreas von Deimling
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Rodrigo A. P. Martins
- Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail: (POF); (RAPM)
| | - Pierre-Olivier Frappart
- Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- * E-mail: (POF); (RAPM)
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31
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Duursma AM, Driscoll R, Elias JE, Cimprich KA. A role for the MRN complex in ATR activation via TOPBP1 recruitment. Mol Cell 2013; 50:116-22. [PMID: 23582259 DOI: 10.1016/j.molcel.2013.03.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 02/11/2013] [Accepted: 03/05/2013] [Indexed: 12/17/2022]
Abstract
The MRN (MRE11-RAD50-NBS1) complex has been implicated in many aspects of the DNA damage response. It has key roles in sensing and processing DNA double-strand breaks, as well as in activation of ATM (ataxia telangiectasia mutated). We reveal a function for MRN in ATR (ATM- and RAD3-related) activation by using defined ATR-activating DNA structures in Xenopus egg extracts. Strikingly, we demonstrate that MRN is required for recruitment of TOPBP1 to an ATR-activating structure that contains a single-stranded DNA (ssDNA) and a double-stranded DNA (dsDNA) junction and that this recruitment is necessary for phosphorylation of CHK1. We also show that the 911 (RAD9-RAD1-HUS1) complex is not required for TOPBP1 recruitment but is essential for TOPBP1 function. Thus, whereas MRN is required for TOPBP1 recruitment at an ssDNA-to-dsDNA junction, 911 is required for TOPBP1 "activation." These findings provide molecular insights into how ATR is activated.
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Affiliation(s)
- Anja M Duursma
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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32
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Abstract
A number of DNA repair disorders are known to cause neurological problems. These disorders can be broadly characterised into early developmental, mid-to-late developmental or progressive. The exact developmental processes that are affected can influence disease pathology, with symptoms ranging from early embryonic lethality to late-onset ataxia. The category these diseases belong to depends on the frequency of lesions arising in the brain, the role of the defective repair pathway, and the nature of the mutation within the patient. Using observations from patients and transgenic mice, we discuss the importance of double strand break repair during neuroprogenitor proliferation and brain development and the repair of single stranded lesions in neuronal function and maintenance.
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Affiliation(s)
- Stuart L Rulten
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
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33
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Shiotani B, Nguyen HD, Håkansson P, Maréchal A, Tse A, Tahara H, Zou L. Two distinct modes of ATR activation orchestrated by Rad17 and Nbs1. Cell Rep 2013; 3:1651-62. [PMID: 23684611 DOI: 10.1016/j.celrep.2013.04.018] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 04/05/2013] [Accepted: 04/19/2013] [Indexed: 11/15/2022] Open
Abstract
The ATM- and Rad3-related (ATR) kinase is a master regulator of the DNA damage response, yet how ATR is activated toward different substrates is still poorly understood. Here, we show that ATR phosphorylates Chk1 and RPA32 through distinct mechanisms at replication-associated DNA double-stranded breaks (DSBs). In contrast to the rapid phosphorylation of Chk1, RPA32 is progressively phosphorylated by ATR at Ser33 during DSB resection prior to the phosphorylation of Ser4/Ser8 by DNA-PKcs. Surprisingly, despite its reliance on ATR and TopBP1, substantial RPA32 Ser33 phosphorylation occurs in a Rad17-independent but Nbs1-dependent manner in vivo and in vitro. Importantly, the role of Nbs1 in RPA32 phosphorylation can be separated from ATM activation and DSB resection, and it is dependent upon the interaction of Nbs1 with RPA. An Nbs1 mutant that is unable to bind RPA fails to support proper recovery of collapsed replication forks, suggesting that the Nbs1-mediated mode of ATR activation is important for the repair of replication-associated DSBs.
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Affiliation(s)
- Bunsyo Shiotani
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
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34
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ATM deficiency results in accumulation of DNA-topoisomerase I covalent intermediates in neural cells. PLoS One 2013; 8:e58239. [PMID: 23626666 PMCID: PMC3634035 DOI: 10.1371/journal.pone.0058239] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 02/01/2013] [Indexed: 12/20/2022] Open
Abstract
Accumulation of peptide-linked DNA breaks contributes to neurodegeration in humans. This is typified by defects in tyrosyl DNA phosphodiesterase 1 (TDP1) and human hereditary ataxia. TDP1 primarily operates at single-strand breaks (SSBs) created by oxidative stress or by collision of transcription machinery with topoisomerase I intermediates (Top1-CCs). Cellular and cell-free studies have shown that Top1 at stalled Top1-CCs is first degraded to a small peptide resulting in Top1-SSBs, which are the primary substrates for TDP1. Here we established an assay to directly compare Top1-SSBs and Top1-CCs. We subsequently employed this assay to reveal an increased steady state level of Top1-CCs in neural cells lacking Atm; the protein mutated in ataxia telangiectasia. Our data suggest that the accumulation of endogenous Top1-CCs in Atm-/- neural cells is primarily due to elevated levels of reactive oxygen species. Biochemical purification of Top1-CCs from neural cell extract and the use of Top1 poisons further confirmed a role for Atm during the formation/resolution of Top1-CCs. Finally, we report that global transcription is reduced in Atm-/- neural cells and fails to recover to normal levels following Top1-mediated DNA damage. Together, these data identify a distinct role for ATM during the formation/resolution of neural Top1-CCs and suggest that their accumulation contributes to the neuropathology of ataxia telangiectasia.
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35
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Lee J, Dunphy WG. The Mre11-Rad50-Nbs1 (MRN) complex has a specific role in the activation of Chk1 in response to stalled replication forks. Mol Biol Cell 2013; 24:1343-53. [PMID: 23468519 PMCID: PMC3639046 DOI: 10.1091/mbc.e13-01-0025] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The activation of Chk1 in response to stalled replication forks involves a pathway containing ATR, TopBP1, Rad17, and Claspin. We show that the Mre11-Rad50-Nbs1 (MRN) complex also has an important role in this pathway that is distinct from its role in response to double-stranded DNA breaks. These studies reveal a novel insight into the functions of the MRN complex. The activation of Chk1 in response to stalled replication forks in Xenopus egg extracts involves a complex pathway containing ATM and Rad3-related (ATR), topoisomerase IIβ-binding protein 1 (TopBP1), Rad17, the Rad9-Hus1-Rad1 (9-1-1) complex, and Claspin. We have observed that egg extracts lacking the Mre11-Rad50-Nbs1 (MRN) complex show greatly, although not completely, reduced activation of Chk1 in response to replication blockages. Depletion of both Rad17 and MRN leads to a further, essentially complete, reduction in the activation of Chk1. Thus, Rad17 and MRN act in at least a partially additive manner in promoting activation of Chk1. There was not an obvious change in the binding of RPA, ATR, Rad17, or the 9-1-1 complex to chromatin in aphidicolin (APH)-treated, MRN-depleted extracts. However, there was a substantial reduction in the binding of TopBP1. In structure–function studies of the MRN complex, we found that the Mre11 subunit is necessary for the APH-induced activation of Chk1. Moreover, a nuclease-deficient mutant of Mre11 cannot substitute for wild-type Mre11 in this process. These results indicate that the MRN complex, in particular the nuclease activity of Mre11, plays an important role in the activation of Chk1 in response to stalled replication forks. These studies reveal a previously unknown property of the MRN complex in genomic stability.
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Affiliation(s)
- Joon Lee
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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36
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Kobayashi M, Hayashi N, Takata M, Yamamoto KI. NBS1 directly activates ATR independently of MRE11 and TOPBP1. Genes Cells 2013; 18:238-46. [PMID: 23368512 DOI: 10.1111/gtc.12031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/07/2012] [Indexed: 11/29/2022]
Abstract
NBS1 plays unique and essential roles in ATM activation in response to DNA double-strand breaks. We found that CHK1 phosphorylation and FANCD2 ubiquitination induced by various DNA replication-stalling agents were abrogated in Nbs1 knockout DT40 cells but not in conditional Mre11 knockout cells, indicating an MRE11-independent role for NBS1 in ATR activation. The results of in vitro ATR kinase assay indicated that the N-terminal region of NBS1 directly activates ATR independently of TOPBP1, consistent with the findings that this region of NBS1 directly interacts with ATR. This conclusion was furthermore supported by the results of in vivo experiments; the expression of the N-terminal region of NBS1 fused to PCNA induces ATR activation in Rad17 knockout cells, and the expression of the ATR activation domain of TOPBP1 fused to PCNA induces ATR activation in Nbs1 knockout cells. These results therefore indicate that NBS1 and TOPBP1 have the potential to activate ATR independently, although both are required for functional activation of ATR in vivo.
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Affiliation(s)
- Masahiko Kobayashi
- Department of Molecular Pathology, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan.
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37
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Beishline K, Kelly CM, Olofsson BA, Koduri S, Emrich J, Greenberg RA, Azizkhan-Clifford J. Sp1 facilitates DNA double-strand break repair through a nontranscriptional mechanism. Mol Cell Biol 2012; 32:3790-9. [PMID: 22826432 PMCID: PMC3430196 DOI: 10.1128/mcb.00049-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 07/08/2012] [Indexed: 12/18/2022] Open
Abstract
Sp1 is a ubiquitously expressed transcription factor that is phosphorylated by ataxia telangiectasia mutated kinase (ATM) in response to ionizing radiation and H(2)O(2). Here, we show by indirect immunofluorescence that Sp1 phosphorylated on serine 101 (pSp1) localizes to ionizing radiation-induced foci with phosphorylated histone variant γH2Ax and members of the MRN (Mre11, Rad50, and Nbs1) complex. More precise analysis of occupancy of DNA double-strand breaks (DSBs) by chromatin immunoprecipitation (ChIP) shows that Sp1, like Nbs1, resides within 200 bp of DSBs. Using laser microirradiation of cells, we demonstrate that pSp1 is present at DNA DSBs by 7.5 min after induction of damage and remains at the break site for at least 8 h. Depletion of Sp1 inhibits repair of site-specific DNA breaks, and the N-terminal 182-amino-acid peptide, which contains targets of ATM kinase but lacks the zinc finger DNA binding domain, is phosphorylated, localizes to DSBs, and rescues the repair defect resulting from Sp1 depletion. Together, these data demonstrate that Sp1 is rapidly recruited to the region immediately adjacent to sites of DNA DSBs and is required for DSB repair, through a mechanism independent of its sequence-directed transcriptional effects.
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Affiliation(s)
- Kate Beishline
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Crystal M. Kelly
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Beatrix A. Olofsson
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Sravanthi Koduri
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Jacqueline Emrich
- Department of Radiation Oncology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Roger A. Greenberg
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jane Azizkhan-Clifford
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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38
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Thompson R, Montano R, Eastman A. The Mre11 nuclease is critical for the sensitivity of cells to Chk1 inhibition. PLoS One 2012; 7:e44021. [PMID: 22937147 PMCID: PMC3427249 DOI: 10.1371/journal.pone.0044021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 07/31/2012] [Indexed: 11/18/2022] Open
Abstract
The Chk1 kinase is required for the arrest of cell cycle progression when DNA is damaged, and for stabilizing stalled replication forks. As a consequence, many Chk1 inhibitors have been developed and tested for their potential to enhance DNA damage-induced tumor cell killing. However, inhibition of Chk1 alone, without any additional exogenous agent, can be cytotoxic. Understanding the underlying mechanisms of this sensitivity is critical for defining which patients might respond best to therapy with Chk1 inhibitors. We have investigated the mechanism of sensitivity in U2OS osteosarcoma cells. Upon incubation with the Chk1 inhibitor MK-8776, single-stranded DNA regions (ssDNA) and double-strand breaks (DSB) begin to appear within 6 h. These DSB have been attributed to the structure-specific DNA endonuclease, Mus81. The Mre11/Rad50/Nbs1 complex is known to be responsible for the resection of DSB to ssDNA. However, we show that inhibition of the Mre11 nuclease activity leads, not only to a decrease in the amount of ssDNA following Chk1 inhibition, but also inhibits the formation of DSB, suggesting that DSB are a consequence of ssDNA formation. These findings were corroborated by the discovery that Mre11-deficient ATLD1 cells are highly resistant to MK-8776 and form neither ssDNA nor DSB following treatment. However, once complimented with exogenous Mre11, the cells accumulate both ssDNA and DSB when incubated with MK-8776. Our findings suggest that Mre11 provides the link between aberrant activation of Cdc25A/Cdk2 and Mus81. The results highlight a novel role for Mre11 in the production of DSB and may help define which tumors are more sensitive to MK-8776 alone or in combination with DNA damaging agents.
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Affiliation(s)
- Ruth Thompson
- Department of Pharmacology and Toxicology, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Norris Cotton Cancer Center, Lebanon, New Hampshire, United States of America
| | - Ryan Montano
- Department of Pharmacology and Toxicology, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Norris Cotton Cancer Center, Lebanon, New Hampshire, United States of America
| | - Alan Eastman
- Department of Pharmacology and Toxicology, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Norris Cotton Cancer Center, Lebanon, New Hampshire, United States of America
- * E-mail:
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39
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Falck J, Forment JV, Coates J, Mistrik M, Lukas J, Bartek J, Jackson SP. CDK targeting of NBS1 promotes DNA-end resection, replication restart and homologous recombination. EMBO Rep 2012; 13:561-8. [PMID: 22565321 PMCID: PMC3367243 DOI: 10.1038/embor.2012.58] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/28/2012] [Accepted: 04/13/2012] [Indexed: 12/14/2022] Open
Abstract
The conserved MRE11–RAD50–NBS1 (MRN) complex is an important sensor of DNA double-strand breaks (DSBs) and facilitates DNA repair by homologous recombination (HR) and end joining. Here, we identify NBS1 as a target of cyclin-dependent kinase (CDK) phosphorylation. We show that NBS1 serine 432 phosphorylation occurs in the S, G2 and M phases of the cell cycle and requires CDK activity. This modification stimulates MRN-dependent conversion of DSBs into structures that are substrates for repair by HR. Impairment of NBS1 phosphorylation not only negatively affects DSB repair by HR, but also prevents resumption of DNA replication after replication-fork stalling. Thus, CDK-mediated NBS1 phosphorylation defines a molecular switch that controls the choice of repair mode for DSBs.
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Affiliation(s)
- Jacob Falck
- Department of Biochemistry, Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
- Centre for Genotoxic Stress Research, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark
| | - Josep V Forment
- Department of Biochemistry, Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Julia Coates
- Department of Biochemistry, Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Martin Mistrik
- Centre for Genotoxic Stress Research, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark
- Institute of Molecular and Translational Medicine, Palacky University, Olomouc CZ-77515, Czech Republic
| | - Jiri Lukas
- Centre for Genotoxic Stress Research, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark
| | - Jiri Bartek
- Centre for Genotoxic Stress Research, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark
- Institute of Molecular and Translational Medicine, Palacky University, Olomouc CZ-77515, Czech Republic
| | - Stephen P Jackson
- Department of Biochemistry, Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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40
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Abstract
Nijmegen breakage syndrome (NBS) is a rare autosomal recessive syndrome of chromosomal instability mainly characterized by microcephaly at birth, combined immunodeficiency and predisposition to malignancies. Due to a founder mutation in the underlying NBN gene (c.657_661del5) the disease is encountered most frequently among Slavic populations. The principal clinical manifestations of the syndrome are: microcephaly, present at birth and progressive with age, dysmorphic facial features, mild growth retardation, mild-to-moderate intellectual disability, and, in females, hypergonadotropic hypogonadism. Combined cellular and humoral immunodeficiency with recurrent sinopulmonary infections, a strong predisposition to develop malignancies (predominantly of lymphoid origin) and radiosensitivity are other integral manifestations of the syndrome. The NBN gene codes for nibrin which, as part of a DNA repair complex, plays a critical nuclear role wherever double-stranded DNA ends occur, either physiologically or as a result of mutagenic exposure. Laboratory findings include: (1) spontaneous chromosomal breakage in peripheral T lymphocytes with rearrangements preferentially involving chromosomes 7 and 14, (2) sensitivity to ionizing radiation or radiomimetics as demonstrated in vitro by cytogenetic methods or by colony survival assay, (3) radioresistant DNA synthesis, (4) biallelic hypomorphic mutations in the NBN gene, and (5) absence of full-length nibrin protein. Microcephaly and immunodeficiency are common to DNA ligase IV deficiency (LIG4 syndrome) and severe combined immunodeficiency with microcephaly, growth retardation, and sensitivity to ionizing radiation due to NHEJ1 deficiency (NHEJ1 syndrome). In fact, NBS was most commonly confused with Fanconi anaemia and LIG4 syndrome. Genetic counselling should inform parents of an affected child of the 25% risk for further children to be affected. Prenatal molecular genetic diagnosis is possible if disease-causing mutations in both alleles of the NBN gene are known. No specific therapy is available for NBS, however, hematopoietic stem cell transplantation may be one option for some patients. Prognosis is generally poor due to the extremely high rate of malignancies. Zespół Nijmegen (Nijmegen breakage syndrome; NBS) jest rzadkim schorzeniem z wrodzoną niestabilnością chromosomową dziedziczącym się w sposób autosomalny recesywny, charakteryzującym się przede wszystkim wrodzonym małogłowiem, złożonymi niedoborami odporności i predyspozycją do rozwoju nowotworów. Choroba występuje najczęściej w populacjach słowiańskich, w których uwarunkowana jest mutacją założycielską w genie NBN (c.657_661del5). Do najważniejszych objawów zespołu zalicza się: małogłowie obecne od urodzenia i postępujące z wiekiem, charakterystyczne cechy dysmorfii twarzy, opóźnienie wzrastania, niepełnosprawność intelektualną w stopniu lekkim do umiarkowanego oraz hipogonadyzm hipogonadotropowy u dziewcząt. Na obraz choroby składają się także: niedobór odporności komórkowej i humoralnej, który jest przyczyną nawracających infekcji, znaczna predyspozycja do rozwoju nowotworów złośliwych (zwłaszcza układu chłonnego), a także zwiększona wrażliwość na promieniowanie jonizujące. Wyniki badań laboratoryjnych wykazują: (1) spontaniczną łamliwość chromosomów w limfocytach T krwi obwodowej, z preferencją do rearanżacji chromosomów 7 i 14, (2) nadwrażliwość na promieniowanie jonizujące lub radiomimetyki, co można wykazać metodami in vitro, (3) radiooporność syntezy DNA, (4) hipomorficzne mutacje na obu allelach genu NBN, oraz (5) brak w komórkach pełnej cząsteczki białka, nibryny. Małogłowie i niedobór odporności występują także w zespole niedoboru ligazy IV (LIG4) oraz w zespole niedoboru NHEJ1. Rodzice powinni otrzymać poradę genetyczną ze względu na wysokie ryzyko (25%) powtórzenia się choroby u kolejnego potomstwa. Możliwe jest zaproponowanie molekularnej diagnostyki prenatalnej jeżeli znane są obie mutacje będące przyczyną choroby. Nie ma możliwości zaproponowania specyficznej terapii, ale przeszczep szpiku może być alternatywą dla niektórych pacjentów. Generalnie prognoza nie jest pomyślna z uwagi na wysokie ryzyko rozwoju nowotworu.
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Tomimatsu N, Mukherjee B, Deland K, Kurimasa A, Bolderson E, Khanna KK, Burma S. Exo1 plays a major role in DNA end resection in humans and influences double-strand break repair and damage signaling decisions. DNA Repair (Amst) 2012; 11:441-8. [PMID: 22326273 DOI: 10.1016/j.dnarep.2012.01.006] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 12/28/2011] [Accepted: 01/09/2012] [Indexed: 02/03/2023]
Abstract
The resection of DNA double-strand breaks (DSBs) to generate ssDNA tails is a pivotal event in the cellular response to these breaks. In the two-step model of resection, primarily elucidated in yeast, initial resection by Mre11-CtIP is followed by extensive resection by two distinct pathways involving Exo1 or BLM/WRN-Dna2. However, resection pathways and their exact contributions in humans in vivo are not as clearly worked out as in yeast. Here, we examined the contribution of Exo1 to DNA end resection in humans in vivo in response to ionizing radiation (IR) and its relationship with other resection pathways (Mre11-CtIP or BLM/WRN). We find that Exo1 plays a predominant role in resection in human cells along with an alternate pathway dependent on WRN. While Mre11 and CtIP stimulate resection in human cells, they are not absolutely required for this process and Exo1 can function in resection even in the absence of Mre11-CtIP. Interestingly, the recruitment of Exo1 to DNA breaks appears to be inhibited by the NHEJ protein Ku80, and the higher level of resection that occurs upon siRNA-mediated depletion of Ku80 is dependent on Exo1. In addition, Exo1 may be regulated by 53BP1 and Brca1, and the restoration of resection in BRCA1-deficient cells upon depletion of 53BP1 is dependent on Exo1. Finally, we find that Exo1-mediated resection facilitates a transition from ATM- to ATR-mediated cell cycle checkpoint signaling. Our results identify Exo1 as a key mediator of DNA end resection and DSB repair and damage signaling decisions in human cells.
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Affiliation(s)
- Nozomi Tomimatsu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, USA
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Zhou Z, Bruhn C, Wang ZQ. Differential function of NBS1 and ATR in neurogenesis. DNA Repair (Amst) 2012; 11:210-21. [DOI: 10.1016/j.dnarep.2011.10.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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43
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A distinct response to endogenous DNA damage in the development of Nbs1-deficient cortical neurons. Cell Res 2012; 22:859-72. [PMID: 22212482 PMCID: PMC3343649 DOI: 10.1038/cr.2012.3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Microcephaly is a clinical characteristic for human nijmegen breakage syndrome (NBS, mutated in NBS1 gene), a chromosomal instability syndrome. However, the underlying molecular pathogenesis remains elusive. In the present study, we demonstrate that neuronal disruption of NBS (Nbn in mice) causes microcephaly characterized by the reduction of cerebral cortex and corpus callosum, recapitulating neuronal anomalies in human NBS. Nbs1-deficient neocortex shows accumulative endogenous DNA damage and defective activation of Ataxia telangiectasia and Rad3-related (ATR)-Chk1 pathway upon DNA damage. Notably, in contrast to massive apoptotic cell death in Nbs1-deficient cerebella, activation of p53 leads to a defective neuroprogenitor proliferation in neocortex, likely via specific persistent induction of hematopoietic zinc finger (Hzf) that preferentially promotes p53-mediated cell cycle arrest whilst inhibiting apoptosis. Moreover, Trp53 mutations substantially rescue the microcephaly in Nbs1-deficient mice. Thus, the present results reveal the first clue that developing neurons at different regions of brain selectively respond to endogenous DNA damage, and underscore an important role for Nbs1 in neurogenesis.
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Kirshner M, Galron R, Frenkel D, Mandelbaum G, Shiloh Y, Wang ZQ, Barzilai A. Malfunctioning DNA Damage Response (DDR) Leads to the Degeneration of Nigro-Striatal Pathway in Mouse Brain. J Mol Neurosci 2011; 46:554-68. [DOI: 10.1007/s12031-011-9643-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 08/26/2011] [Indexed: 12/21/2022]
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O'Driscoll M. Haploinsufficiency of DNA Damage Response Genes and their Potential Influence in Human Genomic Disorders. Curr Genomics 2011; 9:137-46. [PMID: 19440510 PMCID: PMC2679649 DOI: 10.2174/138920208784340795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 03/31/2008] [Accepted: 03/31/2008] [Indexed: 11/22/2022] Open
Abstract
Genomic disorders are a clinically diverse group of conditions caused by gain, loss or re-orientation of a genomic region containing dosage-sensitive genes. One class of genomic disorder is caused by hemizygous deletions resulting in haploinsufficiency of a single or, more usually, several genes. For example, the heterozygous contiguous gene deletion on chromosome 22q11.2 causing DiGeorge syndrome involves at least 20-30 genes. Determining how the copy number variation (CNV) affects human variation and contributes to the aetiology and progression of various genomic disorders represents important questions for the future. Here, I will discuss the functional significance of one form of CNV, haploinsufficiency (i.e. loss of a gene copy), of DNA damage response components and its association with certain genomic disorders. There is increasing evidence that haploinsufficiency for certain genes encoding key players in the cells response to DNA damage, particularly those of the Ataxia Telangiectasia and Rad3-related (ATR)-pathway, has a functional impact. I will review this evidence and present examples of some well known clinically similar genomic disorders that have recently been shown to be defective in the ATR-dependent DNA damage response. Finally, I will discuss the potential implications of a haploinsufficiency-induced defective DNA damage response for the clinical management of certain human genomic disorders.
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Affiliation(s)
- Mark O'Driscoll
- Genome Damage & Stability Centre, University of Sussex, Falmer, Brighton, East Sussex, BN1 9RQ, UK
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Cherubini G, Naim V, Caruso P, Burla R, Bogliolo M, Cundari E, Benihoud K, Saggio I, Rosselli F. The FANC pathway is activated by adenovirus infection and promotes viral replication-dependent recombination. Nucleic Acids Res 2011; 39:5459-73. [PMID: 21421559 PMCID: PMC3141233 DOI: 10.1093/nar/gkr084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Deciphering the crosstalk between a host cell and a virus during infection is important not only to better define viral biology but also to improve our understanding of cellular processes. We identified the FANC pathway as a helper of viral replication and recombination by searching for cellular targets that are modified by adenovirus (Ad) infection and are involved in its outcome. This pathway, which is involved in the DNA damage response and checkpoint control, is altered in Fanconi anaemia, a rare cancer predisposition syndrome. We show here that Ad5 infection activates the FANC pathway independent of the classical DNA damage response. Infection with a non-replicating Ad shows that the presence of viral DNA is not sufficient to induce the monoubiquitination of FANCD2 but still activates the DNA damage response coordinated by phospho-NBS1 and phospho-CHK1. E1A expression alone fails to induce FANCD2 monoubiquitination, indicating that a productive viral infection and/or replication is required for FANC pathway activation. Our data indicate that Ad5 infection induces FANCD2 activation to promote its own replication. Specifically, we show that FANCD2 is involved in the recombination process that accompanies viral DNA replication. This study provides evidence of a DNA damage-independent function of the FANC pathway and identifies a cellular system involved in Ad5 recombination.
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Affiliation(s)
- Gioia Cherubini
- University Paris-Sud, UMR8200 CNRS, Institute Gustave Roussy, Villejuif, France
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Dar I, Yosha G, Elfassy R, Galron R, Wang ZQ, Shiloh Y, Barzilai A. Investigation of the functional link between ATM and NBS1 in the DNA damage response in the mouse cerebellum. J Biol Chem 2011; 286:15361-76. [PMID: 21300797 DOI: 10.1074/jbc.m110.204172] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ataxia-telangiectasia (A-T) and Nijmegen breakage syndrome (NBS) are related genomic instability syndromes characterized by neurological deficits. The NBS1 protein that is defective in NBS is a component of the Mre11/RAD50/NBS1 (MRN) complex, which plays a major role in the early phase of the complex cellular response to double strand breaks (DSBs) in the DNA. Among others, Mre11/RAD50/NBS1 is required for timely activation of the protein kinase ATM (A-T, mutated), which is missing or inactivated in patients with A-T. Understanding the molecular pathology of A-T, primarily its cardinal symptom, cerebellar degeneration, requires investigation of the DSB response in cerebellar neurons, particularly Purkinje cells, which are the first to be lost in A-T patients. Cerebellar cultures derived from mice with different mutations in DNA damage response genes is a useful experimental system to study malfunctioning of the damage response in the nervous system. To clarify the interrelations between murine Nbs1 and Atm, we generated a mouse strain with specific disruption of the Nbs1 gene in the central nervous system on the background of general Atm deficiency (Nbs1-CNS-Δ//Atm(-/-)). This genotype exacerbated several features of both conditions and led to a markedly reduced life span, dramatic decline in the number of cerebellar granule neurons with considerable cerebellar disorganization, abolishment of the white matter, severe reduction in glial cell proliferation, and delayed DSB repair in cerebellar tissue. Combined loss of Nbs1 and Atm in the CNS significantly abrogated the DSB response compared with the single mutation genotypes. Importantly, the data indicate that Atm has cellular roles not regulated by Nbs1 in the murine cerebellum.
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Affiliation(s)
- Inbal Dar
- Department of Neurobiology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Horton JK, Stefanick DF, Zeng JY, Carrozza MJ, Wilson SH. Requirement for NBS1 in the S phase checkpoint response to DNA methylation combined with PARP inhibition. DNA Repair (Amst) 2010; 10:225-34. [PMID: 21130714 DOI: 10.1016/j.dnarep.2010.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/03/2010] [Accepted: 11/08/2010] [Indexed: 11/19/2022]
Abstract
Treatment of PARP-1-expressing cells with the combination of a DNA methylating agent (MMS) and the PARP inhibitor 4-amino-1,8-naphthalimide (4-AN) leads to an ATR/Chk1-dependent S phase checkpoint and cell death by apoptosis. Activation of ATM/Chk2 is involved in sustaining the S phase checkpoint, and double strand break (DSB) accumulation was demonstrated. NBS1, part of the MRN complex that responds to DSBs, is known to modulate ATR- and ATM-dependent checkpoint responses to UV and IR, but a role in the response to PARP inhibition has not been addressed. Here we show that the S phase checkpoint observed 4-8h after MMS+4-AN treatment was absent in cells deficient in NBS1, but was present in NBS1-complemented (i.e., functionally wild-type) cells, indicating a critical role for NBS1 in this checkpoint response. NBS1 was phosphorylated in response to MMS+4-AN treatment, and this was partially ATR- and ATM-dependent, suggesting involvement of both upstream kinases. NBS1 expression had little effect on ATR-mediated phosphorylation of Chk1 and ATM-mediated phosphorylation of Chk2 in response to MMS+4-AN. Phosphorylation of SMC1 was also observed in response to MMS+4-AN treatment. In the absence of ATM and NBS1, phosphorylation of SMC1 was weak, especially at early times after MMS+4-AN treatment. In the absence of ATR activation, reduced SMC1 phosphorylation was seen over a 24h time course. These results suggested that both ATR and ATM phosphorylate SMC1 in response to MMS+4-AN and that this phosphorylation is enhanced by phospho-NBS1. The loss of the MMS+4-AN-induced S phase checkpoint in NBS1-deficient cells may be due to a reduced cellular level of the critical downstream effector, phospho-SMC1.
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Affiliation(s)
- Julie K Horton
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Shimada M, Kobayashi J, Hirayama R, Komatsu K. Differential role of repair proteins, BRCA1/NBS1 and Ku70/DNA-PKcs, in radiation-induced centrosome overduplication. Cancer Sci 2010; 101:2531-7. [DOI: 10.1111/j.1349-7006.2010.01702.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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50
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Amiard S, Charbonnel C, Allain E, Depeiges A, White CI, Gallego ME. Distinct roles of the ATR kinase and the Mre11-Rad50-Nbs1 complex in the maintenance of chromosomal stability in Arabidopsis. THE PLANT CELL 2010; 22:3020-33. [PMID: 20876831 PMCID: PMC2965537 DOI: 10.1105/tpc.110.078527] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 09/04/2010] [Accepted: 09/13/2010] [Indexed: 05/17/2023]
Abstract
Signaling of chromosomal DNA breaks is of primary importance for initiation of repair and, thus, for global genomic stability. Although the Mre11-Rad50-Nbs1 (MRN) complex is the first sensor of double-strand breaks, its role in double-strand break (DSB) signaling is not fully understood. We report the absence of γ-ray-induced, ATM/ATR-dependent histone H2AX phosphorylation in Arabidopsis thaliana rad50 and mre11 mutants, confirming that the MRN complex is required for H2AX phosphorylation by the ATM and ATR kinases in response to irradiation-induced DSB in Arabidopsis. rad50 and mre11 mutants spontaneously activate a DNA damage response, as shown by the presence of γ-H2AX foci and activation of cell cycle arrest in nonirradiated plants. This response is ATR dependent as shown both by the absence of these spontaneous foci and by the wild-type mitotic indices of double rad50 atr and mre11 atr plants. EdU S-phase labeling and fluorescence in situ hybridization analysis using specific subtelomeric probes point to a replicative S-phase origin of this chromosome damage in the double mutants and not to telomere destabilization. Thus, the data presented here show the exclusive involvement of ATR in DNA damage signaling in MRN mutants and provide evidence for a role for ATR in the avoidance of S-phase DNA damage.
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