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Qu H, Wang Y, Yan Q, Fan C, Zhang X, Wang D, Guo C, Chen P, Shi L, Liao Q, Zhou M, Wang F, Zeng Z, Xiang B, Xiong W. CircCDYL2 bolsters radiotherapy resistance in nasopharyngeal carcinoma by promoting RAD51 translation initiation for enhanced homologous recombination repair. J Exp Clin Cancer Res 2024; 43:122. [PMID: 38654320 PMCID: PMC11036759 DOI: 10.1186/s13046-024-03049-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/17/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Radiation therapy stands to be one of the primary approaches in the clinical treatment of malignant tumors. Nasopharyngeal Carcinoma, a malignancy predominantly treated with radiation therapy, provides an invaluable model for investigating the mechanisms underlying radiation therapy resistance in cancer. While some reports have suggested the involvement of circRNAs in modulating resistance to radiation therapy, the underpinning mechanisms remain unclear. METHODS RT-qPCR and in situ hybridization were used to detect the expression level of circCDYL2 in nasopharyngeal carcinoma tissue samples. The effect of circCDYL2 on radiotherapy resistance in nasopharyngeal carcinoma was demonstrated by in vitro and in vivo functional experiments. The HR-GFP reporter assay determined that circCDYL2 affected homologous recombination repair. RNA pull down, RIP, western blotting, IF, and polysome profiling assays were used to verify that circCDYL2 promoted the translation of RAD51 by binding to EIF3D protein. RESULTS We have identified circCDYL2 as highly expressed in nasopharyngeal carcinoma tissues, and it was closely associated with poor prognosis. In vitro and in vivo experiments demonstrate that circCDYL2 plays a pivotal role in promoting radiotherapy resistance in nasopharyngeal carcinoma. Our investigation unveils a specific mechanism by which circCDYL2, acting as a scaffold molecule, recruits eukaryotic translation initiation factor 3 subunit D protein (EIF3D) to the 5'-UTR of RAD51 mRNA, a crucial component of the DNA damage repair pathway to facilitate the initiation of RAD51 translation and enhance homologous recombination repair capability, and ultimately leads to radiotherapy resistance in nasopharyngeal carcinoma. CONCLUSIONS These findings establish a novel role of the circCDYL2/EIF3D/RAD51 axis in nasopharyngeal carcinoma radiotherapy resistance. Our work not only sheds light on the underlying molecular mechanism but also highlights the potential of circCDYL2 as a therapeutic sensitization target and a promising prognostic molecular marker for nasopharyngeal carcinoma.
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Affiliation(s)
- Hongke Qu
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Yumin Wang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China.
| | - Qijia Yan
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China
| | - Chunmei Fan
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Xiangyan Zhang
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Dan Wang
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Can Guo
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Pan Chen
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China
| | - Lei Shi
- Department of Pathology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Qianjin Liao
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China
| | - Ming Zhou
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Fuyan Wang
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China
| | - Zhaoyang Zeng
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China
| | - Bo Xiang
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China.
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China.
| | - Wei Xiong
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, China.
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medical Sciences, Central South University, Changsha, Hunan, 410078, China.
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The Role of DNA Repair in Genomic Instability of Multiple Myeloma. Int J Mol Sci 2022; 23:ijms23105688. [PMID: 35628498 PMCID: PMC9144728 DOI: 10.3390/ijms23105688] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 02/01/2023] Open
Abstract
Multiple Myeloma (MM) is a B cell malignancy marked by genomic instability that arises both through pathogenesis and during disease progression. Despite recent advances in therapy, MM remains incurable. Recently, it has been reported that DNA repair can influence genomic changes and drug resistance in MM. The dysregulation of DNA repair function may provide an alternative explanation for genomic instability observed in MM cells and in cells derived from MM patients. This review provides an overview of DNA repair pathways with a special focus on their involvement in MM and discusses the role they play in MM progression and drug resistance. This review highlights how unrepaired DNA damage due to aberrant DNA repair response in MM exacerbates genomic instability and chromosomal abnormalities, enabling MM progression and drug resistance.
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Giallongo S, Řeháková D, Biagini T, Lo Re O, Raina P, Lochmanová G, Zdráhal Z, Resnick I, Pata P, Pata I, Mistrík M, de Magalhães JP, Mazza T, Koutná I, Vinciguerra M. Histone Variant macroH2A1.1 Enhances Nonhomologous End Joining-dependent DNA Double-strand-break Repair and Reprogramming Efficiency of Human iPSCs. Stem Cells 2022; 40:35-48. [PMID: 35511867 PMCID: PMC9199840 DOI: 10.1093/stmcls/sxab004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/02/2021] [Indexed: 01/21/2023]
Abstract
DNA damage repair (DDR) is a safeguard for genome integrity maintenance. Increasing DDR efficiency could increase the yield of induced pluripotent stem cells (iPSC) upon reprogramming from somatic cells. The epigenetic mechanisms governing DDR during iPSC reprogramming are not completely understood. Our goal was to evaluate the splicing isoforms of histone variant macroH2A1, macroH2A1.1, and macroH2A1.2, as potential regulators of DDR during iPSC reprogramming. GFP-Trap one-step isolation of mtagGFP-macroH2A1.1 or mtagGFP-macroH2A1.2 fusion proteins from overexpressing human cell lines, followed by liquid chromatography-tandem mass spectrometry analysis, uncovered macroH2A1.1 exclusive interaction with Poly-ADP Ribose Polymerase 1 (PARP1) and X-ray cross-complementing protein 1 (XRCC1). MacroH2A1.1 overexpression in U2OS-GFP reporter cells enhanced specifically nonhomologous end joining (NHEJ) repair pathway, while macroH2A1.1 knock-out (KO) mice showed an impaired DDR capacity. The exclusive interaction of macroH2A1.1, but not macroH2A1.2, with PARP1/XRCC1, was confirmed in human umbilical vein endothelial cells (HUVEC) undergoing reprogramming into iPSC through episomal vectors. In HUVEC, macroH2A1.1 overexpression activated transcriptional programs that enhanced DDR and reprogramming. Consistently, macroH2A1.1 but not macroH2A1.2 overexpression improved iPSC reprogramming. We propose the macroH2A1 splicing isoform macroH2A1.1 as a promising epigenetic target to improve iPSC genome stability and therapeutic potential.
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Affiliation(s)
- Sebastiano Giallongo
- International Clinical Research Center, St. Anne’s University Hospital, Brno, Czech Republic
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Daniela Řeháková
- International Clinical Research Center, St. Anne’s University Hospital, Brno, Czech Republic
| | - Tommaso Biagini
- Laboratory of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Oriana Lo Re
- International Clinical Research Center, St. Anne’s University Hospital, Brno, Czech Republic
- Department of Translational Stem Cell Biology, Research Institute of the Medical University of Varna (RIMUV), Varna, Bulgaria
| | - Priyanka Raina
- Integrative Genomics of Ageing Group, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Gabriela Lochmanová
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic
| | - Igor Resnick
- Department of Translational Stem Cell Biology, Research Institute of the Medical University of Varna (RIMUV), Varna, Bulgaria
- Program for Hematology, Immunology, BMT and Cell therapy, St. Marina University Hospital, Varna, Bulgaria
- Department of Medical Genetics, Medical University of Varna, Varna, Bulgaria
| | - Pille Pata
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
- IVEX Lab, Akadeemia 15, Tallinn, Estonia
| | - Illar Pata
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Martin Mistrík
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - João Pedro de Magalhães
- Integrative Genomics of Ageing Group, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Tommaso Mazza
- Department of Translational Stem Cell Biology, Research Institute of the Medical University of Varna (RIMUV), Varna, Bulgaria
| | - Irena Koutná
- International Clinical Research Center, St. Anne’s University Hospital, Brno, Czech Republic
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Manlio Vinciguerra
- International Clinical Research Center, St. Anne’s University Hospital, Brno, Czech Republic
- Department of Translational Stem Cell Biology, Research Institute of the Medical University of Varna (RIMUV), Varna, Bulgaria
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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Dysfunctional activity of classical DNA end-joining renders acquired resistance to carboplatin in human ovarian cancer cells. Cancer Lett 2021; 520:267-280. [PMID: 34375710 DOI: 10.1016/j.canlet.2021.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/13/2021] [Accepted: 08/02/2021] [Indexed: 12/13/2022]
Abstract
Ovarian cancer is the deadliest gynecological malignancy worldwide. Although chemotherapy is required as the most standard treatment strategy for ovarian cancer, the survival rates are very low, largely because of high incidence of recurrence due to resistance to conventional surgery and genotoxic chemotherapies. Carboplatin-resistant ovarian cancer cells were generated by continuous treatment over six months. Carboplatin-resistance induced morphological alterations and promoted the rates of proliferation and migration of SKOV3 compared to the parental cells. Interestingly, carboplatin-resistant SKOV3 showed the high levels of γH2AX foci formed at the basal level, and the levels of γH2AX foci remained even after the recovery time, suggesting that the DNA damage response and repair machinery were severely attenuated by carboplatin-resistance. Surprisingly, the expression levels of XRCC4, a critical factor in non-homologous end joining (NHEJ) DNA repair, were significantly decreased in carboplatin-resistant SKOV3 compared with those in non-resistant controls. Furthermore, restoration of NHEJ in carboplatin-resistant SKOV3 by suppression of ABCB1 and/or AR re-sensitized carboplatin-resistant cells to genotoxic stress and reduced their proliferation ability. Our findings suggest that attenuation of the NHEJ DNA repair machinery mediated by resistance to genotoxic stress might be a critical cause of chemoresistance in patients with ovarian cancer.
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Gao C, Jin G, Forbes E, Mangala LS, Wang Y, Rodriguez-Aguayo C, Amero P, Bayraktar E, Yan Y, Lopez-Berestein G, Broaddus RR, Sood AK, Xue F, Zhang W. Inactivating Mutations of the IK Gene Weaken Ku80/Ku70-Mediated DNA Repair and Sensitize Endometrial Cancer to Chemotherapy. Cancers (Basel) 2021; 13:2487. [PMID: 34065218 PMCID: PMC8160817 DOI: 10.3390/cancers13102487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/05/2021] [Accepted: 05/17/2021] [Indexed: 11/17/2022] Open
Abstract
IK is a mitotic factor that promotes cell cycle progression. Our previous investigation of 271 endometrial cancer (EC) samples from the Cancer Genome Atlas (TCGA) dataset showed IK somatic mutations were enriched in a cluster of patients with high-grade and high-stage cancers, and this group had longer survival. This study provides insight into how IK somatic mutations contribute to EC pathophysiology. We analyzed the somatic mutational landscape of IK gene in 547 EC patients using expanded TCGA dataset. Co-immunoprecipitation and mass spectrometry were used to identify protein interactions. In vitro and in vivo experiments were used to evaluate IK's role in EC. The patients with IK-inactivating mutations had longer survival during 10-year follow-up. Frameshift and stop-gain were common mutations and were associated with decreased IK expression. IK knockdown led to enrichment of G2/M phase cells, inactivation of DNA repair signaling mediated by heterodimerization of Ku80 and Ku70, and sensitization of EC cells to cisplatin treatment. IK/Ku80 mutations were accompanied by higher mutation rates and associated with significantly better overall survival. Inactivating mutations of IK gene and loss of IK protein expression were associated with weakened Ku80/Ku70-mediated DNA repair, increased mutation burden, and better response to chemotherapy in patients with EC.
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Affiliation(s)
- Chao Gao
- Department of Cancer Biology, Wake Forest Baptist Comprehensive Cancer Center, Winston-Salem, NC 27157, USA; (C.G.); (G.J.); (E.F.)
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China; (Y.W.); (Y.Y.)
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin 300052, China
| | - Guangxu Jin
- Department of Cancer Biology, Wake Forest Baptist Comprehensive Cancer Center, Winston-Salem, NC 27157, USA; (C.G.); (G.J.); (E.F.)
| | - Elizabeth Forbes
- Department of Cancer Biology, Wake Forest Baptist Comprehensive Cancer Center, Winston-Salem, NC 27157, USA; (C.G.); (G.J.); (E.F.)
| | - Lingegowda S. Mangala
- Department of Gynecologic Oncology and Reproductive Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (L.S.M.); (E.B.); (A.K.S.)
- Center for RNA Interference and Non-Coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (C.R.-A.); (G.L.-B.)
| | - Yingmei Wang
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China; (Y.W.); (Y.Y.)
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin 300052, China
| | - Cristian Rodriguez-Aguayo
- Center for RNA Interference and Non-Coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (C.R.-A.); (G.L.-B.)
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA;
| | - Paola Amero
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA;
| | - Emine Bayraktar
- Department of Gynecologic Oncology and Reproductive Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (L.S.M.); (E.B.); (A.K.S.)
- Center for RNA Interference and Non-Coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (C.R.-A.); (G.L.-B.)
| | - Ye Yan
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China; (Y.W.); (Y.Y.)
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin 300052, China
| | - Gabriel Lopez-Berestein
- Center for RNA Interference and Non-Coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (C.R.-A.); (G.L.-B.)
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA;
| | - Russell R. Broaddus
- Department of Pathology & Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA;
| | - Anil K. Sood
- Department of Gynecologic Oncology and Reproductive Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (L.S.M.); (E.B.); (A.K.S.)
- Center for RNA Interference and Non-Coding RNAs, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; (C.R.-A.); (G.L.-B.)
| | - Fengxia Xue
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin 300052, China; (Y.W.); (Y.Y.)
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin 300052, China
| | - Wei Zhang
- Department of Cancer Biology, Wake Forest Baptist Comprehensive Cancer Center, Winston-Salem, NC 27157, USA; (C.G.); (G.J.); (E.F.)
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Ku70 suppresses alternative end joining in G1-arrested progenitor B cells. Proc Natl Acad Sci U S A 2021; 118:2103630118. [PMID: 34006647 DOI: 10.1073/pnas.2103630118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Classical nonhomologous end joining (C-NHEJ) repairs DNA double-strand breaks (DSBs) throughout interphase but predominates in G1 phase when homologous recombination is unavailable. Complexes containing the Ku70/80 ("Ku") and XRCC4/ligase IV (Lig4) core C-NHEJ factors are required, respectively, for sensing and joining DSBs. While XRCC4/Lig4 are absolutely required for joining RAG1/2 endonuclease ("RAG")-initiated DSBs during V(D)J recombination in G1-phase progenitor lymphocytes, cycling cells deficient for XRCC4/Lig4 also can join chromosomal DSBs by alternative end-joining (A-EJ) pathways. Restriction of V(D)J recombination by XRCC4/Lig4-mediated joining has been attributed to RAG shepherding V(D)J DSBs exclusively into the C-NHEJ pathway. Here, we report that A-EJ of DSB ends generated by RAG1/2, Cas9:gRNA, and Zinc finger endonucleases in Lig4-deficient G1-arrested progenitor B cell lines is suppressed by Ku. Thus, while diverse DSBs remain largely as free broken ends in Lig4-deficient G1-arrested progenitor B cells, deletion of Ku70 increases DSB rejoining and translocation levels to those observed in Ku70-deficient counterparts. Correspondingly, while RAG-initiated V(D)J DSB joining is abrogated in Lig4-deficient G1-arrested progenitor B cell lines, joining of RAG-generated DSBs in Ku70-deficient and Ku70/Lig4 double-deficient lines occurs through a translocation-like A-EJ mechanism. Thus, in G1-arrested, Lig4-deficient progenitor B cells are functionally end-joining suppressed due to Ku-dependent blockage of A-EJ, potentially in association with G1-phase down-regulation of Lig1. Finally, we suggest that differential impacts of Ku deficiency versus Lig4 deficiency on V(D)J recombination, neuronal apoptosis, and embryonic development results from Ku-mediated inhibition of A-EJ in the G1 cell cycle phase in Lig4-deficient developing lymphocyte and neuronal cells.
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Profilin-1; a novel regulator of DNA damage response and repair machinery in keratinocytes. Mol Biol Rep 2021; 48:1439-1452. [PMID: 33590416 PMCID: PMC7925496 DOI: 10.1007/s11033-021-06210-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/29/2021] [Indexed: 10/25/2022]
Abstract
Profilin-1 (PFN1) regulates actin polymerization and cytoskeletal growth. Despite the essential roles of PFN1 in cell integration, its subcellular function in keratinocyte has not been elucidated yet. Here we characterize the specific regulation of PFN1 in DNA damage response and repair machinery. PFN1 depletion accelerated DNA damage-mediated apoptosis exhibiting PTEN loss of function instigated by increased phosphorylated inactivation followed by high levels of AKT activation. PFN1 changed its predominant cytoplasmic localization to the nucleus upon DNA damage and subsequently restored the cytoplasmic compartment during the recovery time. Even though γH2AX was recruited at the sites of DNA double strand breaks in response to DNA damage, PFN1-deficient cells failed to recruit DNA repair factors, whereas control cells exhibited significant increases of these genes. Additionally, PFN1 depletion resulted in disruption of PTEN-AKT cascade upon DNA damage and CHK1-mediated cell cycle arrest was not recovered even after the recovery time exhibiting γH2AX accumulation. This might suggest PFN1 roles in regulating DNA damage response and repair machinery to protect cells from DNA damage. Future studies addressing the crosstalk and regulation of PTEN-related DNA damage sensing and repair pathway choice by PFN1 may further aid to identify new mechanistic insights for various DNA repair disorders.
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Ahmed EA, Alzahrani AM, Scherthan H. Parp1-Dependent DNA Double-Strand Break Repair in Irradiated Late Pachytene Spermatocytes. DNA Cell Biol 2020; 40:209-218. [PMID: 33337266 DOI: 10.1089/dna.2020.5727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Poly (ADP-ribose) polymerase-1 (Parp1) is a member of nuclear enzymes family involved in to the response to genotoxic stresses, DNA repair, and is critical for the maintenance of genome stability. During gametogenesis, genome stability is essential for inheritance and formation of healthy gametes. The latter involves DNA double-strand break (DSB)-driven pairing of homologous chromosomes in first meiotic prophase. By analysis of DSB repair kinetics in male meiotic prophase cells of homologous recombination (HR) and nonhomologous end joining (NHEJ)-deficient mouse models, we previously demonstrated an interplay between HR and the conventional NHEJ repair pathway. In the current work, we evaluate the relative contribution of Parp1-dependent NHEJ to the repair of ectopic ionizing radiation (IR)-induced DSBs in control and Parp1-inhibited mouse pachytene spermatocytes before and after the completion of meiotic recombination in stages VI-XI. The disappearance of large, exogenous DSB-related γ-H2AX foci was quantified 1 and 8 h after 1 Gy γ-irradiation of control and 3,4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)quinolinone (DPQ) Parp1-inhibited mice. Late pachytene control spermatocytes obtained 8 h after IR had repaired >80% of DSBs observed at 1 h after IR. However, only 64% of DSBs were repaired in late spermatocytes of DPQ-treated (Parp1-inhibited) mice. Thus, it appears that Parp1 contributes to the repair of a fraction of DSBs in late prophase I, providing further insights in DNA repair pathway choreography during spermatogenic differentiation.
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Affiliation(s)
- Emad A Ahmed
- Biological Sciences Department, Faculty of Science, King Faisal University, Al-Ahsa, Saudi Arabia.,Laboratory of Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, Assiut, Egypt
| | - Abdullah M Alzahrani
- Biological Sciences Department, Faculty of Science, King Faisal University, Al-Ahsa, Saudi Arabia
| | - Harry Scherthan
- Institut für Radiobiologie der Bundeswehr in Verb. mit der Universität Ulm, Munich, Germany
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Regulation of DNA Damage Response and Homologous Recombination Repair by microRNA in Human Cells Exposed to Ionizing Radiation. Cancers (Basel) 2020; 12:cancers12071838. [PMID: 32650508 PMCID: PMC7408912 DOI: 10.3390/cancers12071838] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
Ionizing radiation may be of both artificial and natural origin and causes cellular damage in living organisms. Radioactive isotopes have been used significantly in cancer therapy for many years. The formation of DNA double-strand breaks (DSBs) is the most dangerous effect of ionizing radiation on the cellular level. After irradiation, cells activate a DNA damage response, the molecular path that determines the fate of the cell. As an important element of this, homologous recombination repair is a crucial pathway for the error-free repair of DNA lesions. All components of DNA damage response are regulated by specific microRNAs. MicroRNAs are single-stranded short noncoding RNAs of 20–25 nt in length. They are directly involved in the regulation of gene expression by repressing translation or by cleaving target mRNA. In the present review, we analyze the biological mechanisms by which miRNAs regulate cell response to ionizing radiation-induced double-stranded breaks with an emphasis on DNA repair by homologous recombination, and its main component, the RAD51 recombinase. On the other hand, we discuss the ability of DNA damage response proteins to launch particular miRNA expression and modulate the course of this process. A full understanding of cell response processes to radiation-induced DNA damage will allow us to develop new and more effective methods of ionizing radiation therapy for cancers, and may help to develop methods for preventing the harmful effects of ionizing radiation on healthy organisms.
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Nakajima NI, Yamauchi M, Kakoti S, Cuihua L, Kato R, Permata TBM, Iijima M, Yajima H, Yasuhara T, Yamada S, Hasegawa S, Shibata A. RNF8 promotes high linear energy transfer carbon-ion-induced DNA double-stranded break repair in serum-starved human cells. DNA Repair (Amst) 2020; 91-92:102872. [PMID: 32502756 DOI: 10.1016/j.dnarep.2020.102872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
The cell-killing effect of radiotherapy largely depends on unrepaired DNA double-stranded breaks (DSBs) or lethal chromosome aberrations induced by DSBs. Thus, the capability of DSB repair is critically important for the cancer-cell-killing effect of ionizing radiation. Here, we investigated the involvement of the DNA damage signaling factors ataxia telangiectasia mutated (ATM), ring finger protein 8 (RNF8), and RNF168 in quiescent G0/G1 cells, which are expressed in the majority of cell populations in tumors, after high linear energy transfer (LET) carbon-ion irradiation. Interestingly, ATM inhibition caused a substantial DSB repair defect after high-LET carbon-ion irradiation. Similarly, RNF8 or RNF168 depletion caused a substantial DSB repair defect. ATM inhibition did not exert an additive effect in RNF8-depleted cells, suggesting that ATM and RNF8 function in the same pathway. Importantly, we found that the RNF8 RING mutant showed a similar DSB repair defect, suggesting the requirement of ubiquitin ligase activity in this repair pathway. The RNF8 FHA domain was also required for DSB repair in this axis. Furthermore, the p53-binding protein 1 (53BP1), which is an important downstream factor in RNF8-dependent DSB repair, was also required for this repair. Importantly, either ATM inhibition or RNF8 depletion increased the frequency of chromosomal breaks, but reduced dicentric chromosome formation, demonstrating that ATM/RNF8 is required for the rejoining of DSB ends for the formation of dicentric chromosomes. Finally, we showed that RNF8 depletion augmented radiosensitivity after high-LET carbon-ion irradiation. This study suggests that the inhibition of RNF8 activity or its downstream pathway may augment the efficacy of high-LET carbon-ion therapy.
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Affiliation(s)
- Nakako Izumi Nakajima
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan.
| | - Motohiro Yamauchi
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Sangeeta Kakoti
- Gunma University Initiative for Advanced Research (GIAR), Gunma University, Maebashi, Gunma, 371-8511, Japan
| | - Liu Cuihua
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Reona Kato
- Laboratory of Molecular Radiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tiara Bunga Mayang Permata
- Department of Radiation Oncology, Faculty of MedicineUniversitas Indonesia - Dr. Cipto Mangunkusumo Hospital, Jakarta, 10430, Indonesia
| | - Moito Iijima
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo,160-8582, Japan
| | - Hirohiko Yajima
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Takaaki Yasuhara
- Laboratory of Molecular Radiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shigeru Yamada
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Sumitaka Hasegawa
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Atsushi Shibata
- Gunma University Initiative for Advanced Research (GIAR), Gunma University, Maebashi, Gunma, 371-8511, Japan.
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12
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Guo QR, Wang H, Yan YD, Liu Y, Su CY, Chen HB, Yan YY, Adhikari R, Wu Q, Zhang JY. The Role of Exosomal microRNA in Cancer Drug Resistance. Front Oncol 2020; 10:472. [PMID: 32318350 PMCID: PMC7154138 DOI: 10.3389/fonc.2020.00472] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/16/2020] [Indexed: 12/19/2022] Open
Abstract
Exosomes affect the initiation and progression of cancers. In the tumor microenvironment, not only cancer cells, but also fibroblasts and immunocytes secrete exosomes. Exosomes act as a communicator between cells by transferring different cargos and microRNAs (miRNAs). Drug resistance is one of the critical factors affecting therapeutic effect in the course of cancer treatment. The currently known mechanisms of drug resistance include drug efflux, alterations in drug metabolism, DNA damage repair, alterations of energy programming, cancer stem cells and epigenetic changes. Many studies have shown that miRNA carried by exosomes is closely associated with the development of drug resistance mediated by the above-mentioned mechanisms. This review article will discuss how exosomal miRNAs regulate the drug resistance.
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Affiliation(s)
- Qiao-ru Guo
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Hui Wang
- Guangzhou Institute of Pediatrics/Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Ying-da Yan
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yun Liu
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Chao-yue Su
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hu-biao Chen
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Yan-yan Yan
- Collaborative Innovation Center for Cancer, Institute of Respiratory and Occupational Diseases, Medical College, Shanxi Datong University, Datong, China
| | - Rameshwar Adhikari
- Research Centre for Applied Science and Technology, Tribhuvan University, Kirtipur, Nepal
| | - Qiang Wu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
- Key Laboratory of Emergency and Trauma of Ministry of Education, School of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, China
| | - Jian-ye Zhang
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
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13
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Lee KJ, Piett CG, Andrews JF, Mann E, Nagel ZD, Gassman NR. Defective base excision repair in the response to DNA damaging agents in triple negative breast cancer. PLoS One 2019; 14:e0223725. [PMID: 31596905 PMCID: PMC6785058 DOI: 10.1371/journal.pone.0223725] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 09/26/2019] [Indexed: 01/08/2023] Open
Abstract
DNA repair defects have been increasingly focused on as therapeutic targets. In hormone-positive breast cancer, XRCC1-deficient tumors have been identified and proposed as targets for combination therapies that damage DNA and inhibit DNA repair pathways. XRCC1 is a scaffold protein that functions in base excision repair (BER) by mediating essential interactions between DNA glycosylases, AP endonuclease, poly(ADP-ribose) polymerase 1, DNA polymerase β (POL β), and DNA ligases. Loss of XRCC1 confers BER defects and hypersensitivity to DNA damaging agents. BER defects have not been evaluated in triple negative breast cancers (TNBC), for which new therapeutic targets and therapies are needed. To evaluate the potential of XRCC1 as an indicator of BER defects in TNBC, we examined XRCC1 expression in the TCGA database and its expression and localization in TNBC cell lines. The TCGA database revealed high XRCC1 expression in TNBC tumors and TNBC cell lines show variable, but mostly high expression of XRCC1. XRCC1 localized outside of the nucleus in some TNBC cell lines, altering their ability to repair base lesions and single-strand breaks. Subcellular localization of POL β also varied and did not correlate with XRCC1 localization. Basal levels of DNA damage correlated with observed changes in XRCC1 expression, localization, and measure repair capacity. The results confirmed that XRCC1 expression changes indicate DNA repair capacity changes but emphasize that basal DNA damage levels along with protein localization are better indicators of DNA repair defects. Given the observed over-expression of XRCC1 in TNBC preclinical models and tumors, XRCC1 expression levels should be assessed when evaluating treatment responses of TNBC preclinical model cells.
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Affiliation(s)
- Kevin J. Lee
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States of America
- University of South Alabama College of Medicine, Mobile, AL, United States of America
| | - Cortt G. Piett
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, United States of America
| | - Joel F. Andrews
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States of America
- University of South Alabama College of Medicine, Mobile, AL, United States of America
| | - Elise Mann
- University of South Alabama College of Medicine, Mobile, AL, United States of America
| | - Zachary D. Nagel
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, United States of America
| | - Natalie R. Gassman
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States of America
- University of South Alabama College of Medicine, Mobile, AL, United States of America
- * E-mail:
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14
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Xie Y, Liu YK, Guo ZP, Guan H, Liu XD, Xie DF, Jiang YG, Ma T, Zhou PK. RBX1 prompts degradation of EXO1 to limit the homologous recombination pathway of DNA double-strand break repair in G1 phase. Cell Death Differ 2019; 27:1383-1397. [PMID: 31562368 PMCID: PMC7205894 DOI: 10.1038/s41418-019-0424-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 09/06/2019] [Accepted: 09/12/2019] [Indexed: 01/12/2023] Open
Abstract
End resection of DNA double-strand breaks (DSBs) to form 3′ single-strand DNA (ssDNA) is critical to initiate the homologous recombination (HR) pathway of DSB repair. HR pathway is strictly limited in the G1-phase cells because of lack of homologous DNA as the templates. Exonuclease 1 (EXO1) is the key molecule responsible for 3′ ssDNA formation of DSB end resection. We revealed that EXO1 is inactivated in G1-phase cells via ubiquitination-mediated degradation, resulting from an elevated expression level of RING-box protein 1 (RBX1) in G1 phase. The increased RBX1 significantly prompted the neddylation of Cullin1 and contributed to the G1 phase-specific degradation of EXO1. Knockdown of RBX1 remarkedly attenuated the degradation of EXO1 and increased the end resection and HR activity in γ-irradiated G1-phase cells, as demonstrated by the increased formation of RPA32, BrdU, and RAD51 foci. And EXO1 depletion mitigated DNA repair defects due to RBX1 reduction. Moreover, increased autophosphorylation of DNA-PKcs at S2056 was found to be responsible for the higher expression level of the RBX1 in the G1 phase. Inactivation of DNA-PKcs decreased RBX1 expression, and simultaneously increased EXO1 expression and DSB end resection in G1-phase cells. This study demonstrates a new mechanism for restraining the HR pathway of DNA DSB repair in G1 phase via RBX1-prompted inactivation of EXO1.
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Affiliation(s)
- Ying Xie
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China.,Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, 410013, Changsha, China
| | - Yi-Ke Liu
- Institute for Chemical Carcinogenesis, State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Zong-Pei Guo
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China
| | - Hua Guan
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China
| | - Xiao-Dan Liu
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China
| | - Da-Fei Xie
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China
| | - Yi-Guo Jiang
- Institute for Chemical Carcinogenesis, State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Teng Ma
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China. .,Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis and Thoracic Tumor Research Institute, 101149, Beijing, China.
| | - Ping-Kun Zhou
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 100850, Beijing, China. .,Institute for Chemical Carcinogenesis, State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China.
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15
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Faraoni I, Graziani G. Role of BRCA Mutations in Cancer Treatment with Poly(ADP-ribose) Polymerase (PARP) Inhibitors. Cancers (Basel) 2018; 10:E487. [PMID: 30518089 PMCID: PMC6316750 DOI: 10.3390/cancers10120487] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 12/29/2022] Open
Abstract
Inhibition of poly(ADP-ribose) polymerase (PARP) activity induces synthetic lethality in mutated BRCA1/2 cancers by selectively targeting tumor cells that fail to repair DNA double strand breaks (DSBs). Clinical studies have confirmed the validity of the synthetic lethality approach and four different PARP inhibitors (PARPi; olaparib, rucaparib, niraparib and talazoparib) have been approved as monotherapies for BRCA-mutated or platinum-sensitive recurrent ovarian cancer and/or for BRCA-mutated HER2-negative metastatic breast cancer. PARPi therapeutic efficacy is higher against tumors harboring deleterious germline or somatic BRCA mutations than in BRCA wild-type tumors. BRCA mutations or intrinsic tumor sensitivity to platinum compounds are both regarded as indicators of deficiency in DSB repair by homologous recombination as well as of favorable response to PARPi. However, not all BRCA-mutated or platinum-responsive patients obtain clinical benefit from these agents. Conversely, a certain percentage of patients with wild-type BRCA or platinum-resistant tumors can still get benefit from PARPi. Thus, additional reliable markers need to be validated in clinical trials to select patients potentially eligible for PARPi-based therapies, in the absence of deleterious BRCA mutations or platinum sensitivity. In this review, we summarize the mechanisms of action of PARPi and the clinical evidence supporting their use as anticancer drugs as well as the additional synthetic lethal partners that might confer sensitivity to PARPi in patients with wild-type BRCA tumors.
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Affiliation(s)
- Isabella Faraoni
- Department of Systems Medicine, University of Rome Tor Vergata, 00173 Rom, Italy.
| | - Grazia Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, 00173 Rom, Italy.
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