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Sriramulu S, Thoidingjam S, Chen WM, Hassan O, Siddiqui F, Brown SL, Movsas B, Green MD, Davis AJ, Speers C, Walker E, Nyati S. BUB1 regulates non-homologous end joining pathway to mediate radioresistance in triple-negative breast cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592812. [PMID: 38766122 PMCID: PMC11100764 DOI: 10.1101/2024.05.07.592812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Background Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer subtype often treated with radiotherapy (RT). Due to its intrinsic heterogeneity and lack of effective targets, it is crucial to identify novel molecular targets that would increase RT efficacy. Here we demonstrate the role of BUB1 (cell cycle Ser/Thr kinase) in TNBC radioresistance and offer a novel strategy to improve TNBC treatment. Methods Gene expression analysis was performed to look at genes upregulated in TNBC patient samples compared to other subtypes. Cell proliferation and clonogenic survivals assays determined the IC 50 of BUB1 inhibitor (BAY1816032) and radiation enhancement ratio (rER) with pharmacologic and genomic BUB1 inhibition. Mammary fat pad xenografts experiments were performed in CB17/SCID. The mechanism through which BUB1 inhibitor sensitizes TNBC cells to radiotherapy was delineated by γ-H2AX foci assays, BLRR, Immunoblotting, qPCR, CHX chase, and cell fractionation assays. Results BUB1 is overexpressed in BC and its expression is considerably elevated in TNBC with poor survival outcomes. Pharmacological or genomic ablation of BUB1 sensitized multiple TNBC cell lines to cell killing by radiation, although breast epithelial cells showed no radiosensitization with BUB1 inhibition. Kinase function of BUB1 is mainly accountable for this radiosensitization phenotype. BUB1 ablation also led to radiosensitization in TNBC tumor xenografts with significantly increased tumor growth delay and overall survival. Mechanistically, BUB1 ablation inhibited the repair of radiation-induced DNA double strand breaks (DSBs). BUB1 ablation stabilized phospho-DNAPKcs (S2056) following RT such that half-lives could not be estimated. In contrast, RT alone caused BUB1 stabilization, but pre-treatment with BUB1 inhibitor prevented stabilization (t 1/2 , ∼8 h). Nuclear and chromatin-enriched fractionations illustrated an increase in recruitment of phospho- and total-DNAPK, and KAP1 to chromatin indicating that BUB1 is indispensable in the activation and recruitment of non-homologous end joining (NHEJ) proteins to DSBs. Additionally, BUB1 staining of TNBC tissue microarrays demonstrated significant correlation of BUB1 protein expression with tumor grade. Conclusions BUB1 ablation sensitizes TNBC cell lines and xenografts to RT and BUB1 mediated radiosensitization may occur through NHEJ. Together, these results highlight BUB1 as a novel molecular target for radiosensitization in women with TNBC.
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Sonmez C, Toia B, Eickhoff P, Matei AM, El Beyrouthy M, Wallner B, Douglas ME, de Lange T, Lottersberger F. DNA-PK controls Apollo's access to leading-end telomeres. Nucleic Acids Res 2024; 52:4313-4327. [PMID: 38407308 PMCID: PMC11077071 DOI: 10.1093/nar/gkae105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 01/23/2024] [Accepted: 02/01/2024] [Indexed: 02/27/2024] Open
Abstract
The complex formed by Ku70/80 and DNA-PKcs (DNA-PK) promotes the synapsis and the joining of double strand breaks (DSBs) during canonical non-homologous end joining (c-NHEJ). In c-NHEJ during V(D)J recombination, DNA-PK promotes the processing of the ends and the opening of the DNA hairpins by recruiting and/or activating the nuclease Artemis/DCLRE1C/SNM1C. Paradoxically, DNA-PK is also required to prevent the fusions of newly replicated leading-end telomeres. Here, we describe the role for DNA-PK in controlling Apollo/DCLRE1B/SNM1B, the nuclease that resects leading-end telomeres. We show that the telomeric function of Apollo requires DNA-PKcs's kinase activity and the binding of Apollo to DNA-PK. Furthermore, AlphaFold-Multimer predicts that Apollo's nuclease domain has extensive additional interactions with DNA-PKcs, and comparison to the cryo-EM structure of Artemis bound to DNA-PK phosphorylated on the ABCDE/Thr2609 cluster suggests that DNA-PK can similarly grant Apollo access to the DNA end. In agreement, the telomeric function of DNA-PK requires the ABCDE/Thr2609 cluster. These data reveal that resection of leading-end telomeres is regulated by DNA-PK through its binding to Apollo and its (auto)phosphorylation-dependent positioning of Apollo at the DNA end, analogous but not identical to DNA-PK dependent regulation of Artemis at hairpins.
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Affiliation(s)
- Ceylan Sonmez
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Patrik Eickhoff
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Andreea Medeea Matei
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Michael El Beyrouthy
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Björn Wallner
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 58 183, Sweden
| | - Max E Douglas
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, NY, NY 10021, USA
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
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Klieber N, Hildebrand LS, Faulhaber E, Symank J, Häck N, Härtl A, Fietkau R, Distel LV. Different Impacts of DNA-PK and mTOR Kinase Inhibitors in Combination with Ionizing Radiation on HNSCC and Normal Tissue Cells. Cells 2024; 13:304. [PMID: 38391917 PMCID: PMC10887161 DOI: 10.3390/cells13040304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
Despite substantial advancements in understanding the pathomechanisms of head and neck squamous cell carcinoma (HNSCC), effective therapy remains challenging. The application of kinase inhibitors (KIs) in HNSCC, specifically mTOR and DNA-PK inhibitors, can increase radiosensitivity and therefore presents a promising strategy when used simultaneously with ionizing radiation (IR) in cancer treatment. Our study focused on the selective DNA-PK-inhibitor AZD7648; the selective mTOR-inhibitor Sapanisertib; and CC-115, a dual inhibitor targeting both mTOR and DNA-PK. The impact of these KIs on HNSCC and normal tissue cells was assessed using various analytical methods including cell death studies, cell cycle analysis, real-time microscopy, colony-forming assays and immunohistochemical staining for γH2AX and downstream mTOR protein p-S6. We detected a strong inhibition of IR-induced DNA double-strand break (DSB) repair, particularly in AZD7648-treated HNSCC, whereas normal tissue cells repaired DNA DSB more efficiently. Additionally, AZD7648 + IR treatment showed a synergistic decline in cell proliferation and clonogenicity, along with an elevated G2/M arrest and cell death in the majority of HNSCC cell lines. CC-115 + IR treatment led to an elevation in G2/M arrest, increased cell death, and a synergistic reduction in cell proliferation, though the effect was notably lower compared to the AZD7648 + IR- treated group. Sapanisertib led to a high cellular toxicity in both HNSCC and normal tissue cells, even in non-irradiated cells. Regarding cell proliferation and the induction of apoptosis and necrosis, Sapanisertib + IR was beneficial only in HPV+ HNSCC. Overall, this study highlights the potential of AZD7648 as a radiosensitizing agent in advanced-stage HPV-positive and negative HNSCC, offering a promising therapeutic strategy. However, the dual mTOR/DNA-PK-I CC-115 did not provide a distinct advantage over the use of selective KIs in our investigations, suggesting limited benefits for its application in KI + IR therapy. Notably, the selective mTOR-inhibitor Sapanisertib was only beneficial in HPV+ HNSCC and should not be applied in HPV- cases.
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Affiliation(s)
- Nina Klieber
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Laura S. Hildebrand
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Eva Faulhaber
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Julia Symank
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Nicole Häck
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Annamaria Härtl
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Rainer Fietkau
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
| | - Luitpold V. Distel
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054 Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), 91054 Erlangen, Germany
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Hu Q, Valle-Inclan JE, Dahiya R, Guyer A, Mazzagatti A, Maurais EG, Engel JL, Cortés-Ciriano I, Ly P. Non-homologous end joining shapes the genomic rearrangement landscape of chromothripsis from mitotic errors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552800. [PMID: 37609143 PMCID: PMC10441393 DOI: 10.1101/2023.08.10.552800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Errors in mitosis can generate micronuclei that entrap mis-segregated chromosomes, which are susceptible to catastrophic fragmentation through a process termed chromothripsis. The reassembly of fragmented chromosomes by error-prone DNA double-strand break (DSB) repair generates a spectrum of simple and complex genomic rearrangements that are associated with human cancers and disorders. How specific DSB repair pathways recognize and process these lesions remains poorly understood. Here we used CRISPR/Cas9 to systematically inactivate distinct DSB processing or repair pathways and interrogated the rearrangement landscape of fragmented chromosomes from micronuclei. Deletion of canonical non-homologous end joining (NHEJ) components, including DNA-PKcs, LIG4, and XLF, substantially reduced the formation of complex rearrangements and shifted the rearrangement landscape toward simple alterations without the characteristic patterns of cancer-associated chromothripsis. Following reincorporation into the nucleus, fragmented chromosomes localize within micronuclei bodies (MN bodies) and undergo successful ligation by NHEJ within a single cell cycle. In the absence of NHEJ, chromosome fragments were rarely engaged by polymerase theta-mediated alternative end-joining or recombination-based mechanisms, resulting in delayed repair kinetics and persistent 53BP1-labeled MN bodies in the interphase nucleus. Prolonged DNA damage signaling from unrepaired fragments ultimately triggered cell cycle arrest. Thus, we provide evidence supporting NHEJ as the exclusive DSB repair pathway generating complex rearrangements following chromothripsis from mitotic errors.
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Affiliation(s)
- Qing Hu
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jose Espejo Valle-Inclan
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Rashmi Dahiya
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Alison Guyer
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Present address: Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Alice Mazzagatti
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Elizabeth G. Maurais
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Justin L. Engel
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Isidro Cortés-Ciriano
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Peter Ly
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Cell Biology, Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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5
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He L, Liang J, Chen C, Chen J, Shen Y, Sun S, Li L. C9orf72 functions in the nucleus to regulate DNA damage repair. Cell Death Differ 2023; 30:716-730. [PMID: 36220889 PMCID: PMC9984389 DOI: 10.1038/s41418-022-01074-0] [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: 10/19/2021] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 03/05/2023] Open
Abstract
The hexanucleotide GGGGCC repeat expansion in the intronic region of C9orf72 is the most common cause of Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The repeat expansion-generated toxic RNAs and dipeptide repeats (DPRs) including poly-GR, have been extensively studied in neurodegeneration. Moreover, haploinsufficiency has been implicated as a disease mechanism but how C9orf72 deficiency contributes to neurodegeneration remains unclear. Here, we show that C9orf72 deficiency exacerbates poly-GR-induced neurodegeneration by attenuating non-homologous end joining (NHEJ) repair. We demonstrate that C9orf72 localizes to the nucleus and is rapidly recruited to sites of DNA damage. C9orf72 deficiency resulted in impaired NHEJ repair through attenuated DNA-PK complex assembly and DNA damage response (DDR) signaling. In mouse models, we found that C9orf72 deficiency exacerbated poly-GR-induced neuronal loss, glial activation, and neuromuscular deficits. Furthermore, DNA damage accumulated in C9orf72-deficient neurons that expressed poly-GR, resulting in excessive activation of PARP-1. PARP-1 inhibition rescued neuronal death in cultured neurons treated with poly-GR peptides. Together, our results support a pathological mechanism where C9orf72 haploinsufficiency synergizes with poly-GR-induced DNA double-strand breaks to exacerbate the accumulation of DNA damage and PARP-1 overactivation in C9orf72 ALS/FTD patients.
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Affiliation(s)
- Liying He
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiaqi Liang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chaonan Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jijun Chen
- Institute of Brain-Intelligence Technology, Zhangjiang Laboratory, Shanghai, China
| | - Yihui Shen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuangshuang Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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6
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Goff NJ, Brenière M, Buehl CJ, de Melo AJ, Huskova H, Ochi T, Blundell TL, Mao W, Yu K, Modesti M, Meek K. Catalytically inactive DNA ligase IV promotes DNA repair in living cells. Nucleic Acids Res 2022; 50:11058-11071. [PMID: 36263813 PMCID: PMC9638927 DOI: 10.1093/nar/gkac913] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/18/2022] [Indexed: 11/17/2022] Open
Abstract
DNA double strand breaks (DSBs) are induced by external genotoxic agents (ionizing radiation or genotoxins) or by internal processes (recombination intermediates in lymphocytes or by replication errors). The DNA ends induced by these genotoxic processes are often not ligatable, requiring potentially mutagenic end-processing to render ends compatible for ligation by non-homologous end-joining (NHEJ). Using single molecule approaches, Loparo et al. propose that NHEJ fidelity can be maintained by restricting end-processing to a ligation competent short-range NHEJ complex that 'maximizes the fidelity of DNA repair'. These in vitro studies show that although this short-range NHEJ complex requires DNA ligase IV (Lig4), its catalytic activity is dispensable. Here using cellular models, we show that inactive Lig4 robustly promotes DNA repair in living cells. Compared to repair products from wild-type cells, those isolated from cells with inactive Lig4 show a somewhat increased fraction that utilize micro-homology (MH) at the joining site consistent with alternative end-joining (a-EJ). But unlike a-EJ in the absence of NHEJ, a large percentage of joints isolated from cells with inactive Lig4 occur with no MH - thus, clearly distinct from a-EJ. Finally, biochemical assays demonstrate that the inactive Lig4 complex promotes the activity of DNA ligase III (Lig3).
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Affiliation(s)
- Noah J Goff
- College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA,Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA,Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Manon Brenière
- Centre de Recherche en Cancérologie de Marseille, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Universiteé, Marseille, France
| | - Christopher J Buehl
- College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA,Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA,Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Abinadabe J de Melo
- Centre de Recherche en Cancérologie de Marseille, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Universiteé, Marseille, France
| | - Hana Huskova
- Centre de Recherche en Cancérologie de Marseille, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Universiteé, Marseille, France
| | - Takashi Ochi
- The Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9TJ, UK
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Weifeng Mao
- College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA,Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Kefei Yu
- College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA,Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Mauro Modesti
- Correspondence may also be addressed to Mauro Modesti.
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Yang X, Yang F, Lan L, Wen N, Li H, Sun X. Potential value of PRKDC as a therapeutic target and prognostic biomarker in pan-cancer. Medicine (Baltimore) 2022; 101:e29628. [PMID: 35801800 PMCID: PMC9259106 DOI: 10.1097/md.0000000000029628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND While protein kinase, DNA-activated, catalytic subunit (PRKDC) plays an important role in double-strand break repair to retain genomic stability, there is still no pan-cancer analysis based on large clinical information on the relationship between PRKDC and different tumors. For the first time, this research used numerous databases to perform a pan-cancer review for PRKDC to explore the possible mechanism of PRKDC in the etiology and outcomes in various tumors. METHODS PRKDC's expression profile and prognostic significance in pan-cancer were investigated based on various databases and online platforms, including TIMER2, GEPIA2, cBioPortal, CPTAC, and SangerBox. We applied the TIMER to identified the interlink of PRKDC and the immune infiltration in assorted tumors, and the SangerBox online platform was adopted to find out the relevance between PRKDC and immune checkpoint genes, tumor mutation burden, and microsatellite instability in tumors. GeneMANIA tool was employed to create a protein-protein interaction analysis, gene set enrichment analysis was conducted to performed gene enrichment analysis. RESULTS Overall, tumor tissue presented a higher degree of PRKDC expression than adjacent normal tissue. Meanwhile, patients with high PRKDC expression have a worse prognosis. PRKDC mutations were present in almost all The Cancer Genome Atlas tumors and might lead to a better survival prognosis. The PRKDC expression level was shown a positive correlation with tumor-infiltrating immune cells. PRKDC high expression cohorts were enriched in "cell cycle" "oocyte meiosis" and "RNA-degradation" signaling pathways. CONCLUSIONS This study revealed the potential value of PRKDC in tumor immunology and as a therapeutic target and prognostic biomarker in pan-cancer.
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Affiliation(s)
- Xiawei Yang
- Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Feng Yang
- Department of Gynocology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Liugen Lan
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Ning Wen
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Haibin Li
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Xuyong Sun
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
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Sudhanva MS, Hariharasudhan G, Jun S, Seo G, Kamalakannan R, Kim HH, Lee JH. MicroRNA-145 Impairs Classical Non-Homologous End-Joining in Response to Ionizing Radiation-Induced DNA Double-Strand Breaks via Targeting DNA-PKcs. Cells 2022; 11:1509. [DOI: https:/doi.org/10.3390/cells11091509 academic] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/18/2023] Open
Abstract
DNA double-strand breaks (DSBs) are one of the most lethal types of DNA damage due to the fact that unrepaired or mis-repaired DSBs lead to genomic instability or chromosomal aberrations, thereby causing cell death or tumorigenesis. The classical non-homologous end-joining pathway (c-NHEJ) is the major repair mechanism for rejoining DSBs, and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is a critical factor in this pathway; however, regulation of DNA-PKcs expression remains unknown. In this study, we demonstrate that miR-145 directly suppresses DNA-PKcs by binding to the 3′-UTR and inhibiting translation, thereby causing an accumulation of DNA damage, impairing c-NHEJ, and rendering cells hypersensitive to ionizing radiation (IR). Of note, miR-145-mediated suppression of DNA damage repair and enhanced IR sensitivity were both reversed by either inhibiting miR-145 or overexpressing DNA-PKcs. In addition, we show that the levels of Akt1 phosphorylation in cancer cells are correlated with miR-145 suppression and DNA-PKcs upregulation. Furthermore, the overexpression of miR-145 in Akt1-suppressed cells inhibited c-NHEJ by downregulating DNA-PKcs. These results reveal a novel miRNA-mediated regulation of DNA repair and identify miR-145 as an important regulator of c-NHEJ.
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9
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MicroRNA-145 Impairs Classical Non-Homologous End-Joining in Response to Ionizing Radiation-Induced DNA Double-Strand Breaks via Targeting DNA-PKcs. Cells 2022; 11:cells11091509. [PMID: 35563814 PMCID: PMC9102532 DOI: 10.3390/cells11091509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
DNA double-strand breaks (DSBs) are one of the most lethal types of DNA damage due to the fact that unrepaired or mis-repaired DSBs lead to genomic instability or chromosomal aberrations, thereby causing cell death or tumorigenesis. The classical non-homologous end-joining pathway (c-NHEJ) is the major repair mechanism for rejoining DSBs, and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is a critical factor in this pathway; however, regulation of DNA-PKcs expression remains unknown. In this study, we demonstrate that miR-145 directly suppresses DNA-PKcs by binding to the 3′-UTR and inhibiting translation, thereby causing an accumulation of DNA damage, impairing c-NHEJ, and rendering cells hypersensitive to ionizing radiation (IR). Of note, miR-145-mediated suppression of DNA damage repair and enhanced IR sensitivity were both reversed by either inhibiting miR-145 or overexpressing DNA-PKcs. In addition, we show that the levels of Akt1 phosphorylation in cancer cells are correlated with miR-145 suppression and DNA-PKcs upregulation. Furthermore, the overexpression of miR-145 in Akt1-suppressed cells inhibited c-NHEJ by downregulating DNA-PKcs. These results reveal a novel miRNA-mediated regulation of DNA repair and identify miR-145 as an important regulator of c-NHEJ.
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10
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Li X, Zou S, Zhou L, Gao A, Xu J, He C, Zhou J, Wu S, Chen Y. RAD18
confers radioresistance of esophagus squamous cell carcinoma through regulating
p‐DNA‐PKcs. Cancer Med 2022; 11:3809-3819. [PMID: 35426246 PMCID: PMC9582675 DOI: 10.1002/cam4.4754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/24/2022] [Accepted: 04/01/2022] [Indexed: 12/14/2022] Open
Abstract
Background Radiotherapy has recently become more common for the treatment of esophageal squamous cell carcinoma (ESCC). Radioresistance, on the other hand, continues to be a major issue because it interferes with the effectiveness of ESCC radiation. It has been demonstrated that RAD18, an E3 ubiquitin‐protein ligase that regulates translesion DNA synthesis (TLS), is implicated in the regulation of genomic integrity and DNA damage response. Methods In the present study, immunohistochemical staining and western blotting were utilized to determine RAD18 expression in ESCC tissues and cells. ESCC cell proliferation was determined using a colony formation assay. Immunofluorescence staining, comet assay, and homologous recombination (HR)/non‐homologous end‐joining (NHEJ) assays were conducted to examine the effect of RAD18 on the DNA damage response in ESCC cells. Results We found that high RAD18 expression was positively associated with a poorer prognosis in patients with ESCC who received radiotherapy. Downregulation of RAD18 expression significantly increased the sensitivity of ESCC cells to irradiation. Moreover, RAD18 knockdown prolonged the repair kinetics of γH2AX foci and resulted in longer comet tails. Furthermore, loss of RAD18 expression markedly decreased non‐homologous end‐joining (NHEJ) activity, but it did not affect homologous recombination (HR)‐mediated double‐strand break repair in ESCC cells. RAD18 upregulated p‐DNA‐dependent protein kinase complex (p‐DNA‐PKc) expression in vivo and in vitro. Conclusions These data indicated that RAD18 may regulate radioresistance by facilitating NHEJ via phosphorylation of DNA‐PKcs in ESCC cells, providing a novel radiotherapy target for ESCC.
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Affiliation(s)
- Xiaoqing Li
- Suzhou Cancer Center Core Laboratory The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Shitao Zou
- Suzhou Cancer Center Core Laboratory The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Liangsu Zhou
- Department of Radiation Oncology The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Aidi Gao
- Suzhou Cancer Center Core Laboratory The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Jing Xu
- Department of Neurology The Second Affiliated Hospital of Nanjing Medical University Nanjing China
| | - Chao He
- Suzhou Cancer Center Core Laboratory The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Jundong Zhou
- Department of Radiation Oncology The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Shuhua Wu
- Department of Geriatrics The Second Affiliated Hospital of Soochow University Suzhou Jiangsu China
| | - Yihong Chen
- Department of Radiation The First Affiliated Hospital of Wanna Medical College Wuhu Anhui China
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11
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Matsumoto Y. Development and Evolution of DNA-Dependent Protein Kinase Inhibitors toward Cancer Therapy. Int J Mol Sci 2022; 23:ijms23084264. [PMID: 35457081 PMCID: PMC9032228 DOI: 10.3390/ijms23084264] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/07/2022] [Accepted: 04/09/2022] [Indexed: 12/04/2022] Open
Abstract
DNA double-strand break (DSB) is considered the most deleterious type of DNA damage, which is generated by ionizing radiation (IR) and a subset of anticancer drugs. DNA-dependent protein kinase (DNA-PK), which is composed of a DNA-PK catalytic subunit (DNA-PKcs) and Ku80-Ku70 heterodimer, acts as the molecular sensor for DSB and plays a pivotal role in DSB repair through non-homologous end joining (NHEJ). Cells deficient for DNA-PKcs show hypersensitivity to IR and several DNA-damaging agents. Cellular sensitivity to IR and DNA-damaging agents can be augmented by the inhibition of DNA-PK. A number of small molecules that inhibit DNA-PK have been developed. Here, the development and evolution of inhibitors targeting DNA-PK for cancer therapy is reviewed. Significant parts of the inhibitors were developed based on the structural similarity of DNA-PK to phosphatidylinositol 3-kinases (PI3Ks) and PI3K-related kinases (PIKKs), including Ataxia-telangiectasia mutated (ATM). Some of DNA-PK inhibitors, e.g., NU7026 and NU7441, have been used extensively in the studies for cellular function of DNA-PK. Recently developed inhibitors, e.g., M3814 and AZD7648, are in clinical trials and on the way to be utilized in cancer therapy in combination with radiotherapy and chemotherapy.
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Affiliation(s)
- Yoshihisa Matsumoto
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
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12
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WASH interacts with Ku to regulate DNA double-stranded break repair. iScience 2022; 25:103676. [PMID: 35036867 PMCID: PMC8749218 DOI: 10.1016/j.isci.2021.103676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/12/2021] [Accepted: 12/20/2021] [Indexed: 12/28/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein and SCAR homolog (WASH), an actin nucleation-promoting factor, is present in the nucleus where it regulates gene transcription and maintains nuclear organization. Here, we show that WASH interacts with core non-homologous end-joining (NHEJ) factors including Ku70/Ku80 and DNA-PKcs, and Ku70/Ku80 is involved in the recruitment of WASH to the sites of DNA double-stranded break (DSB). WASH depletion leads to increased cell sensitivity and impaired DNA repair capacity in response to etoposide-induced DSBs and reduces NHEJ efficiency. Mechanistically, we show that loss of WASH inhibits the phosphorylation of DNA-PKcs, H2AX, and KAP1 after DSB induction and reduces chromatin relaxation and the recruitment of several downstream NHEJ factors to DSBs. Moreover, WASH role in DSB repair depends on its conserved C-terminal VCA domain and Arp2/3 activation. Our findings reveal a function and mechanistic insight for WASH in DNA DSB repair by the NHEJ pathway.
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13
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Gordhandas SB, Manning-Geist B, Henson C, Iyer G, Gardner GJ, Sonoda Y, Moore KN, Aghajanian C, Chui MH, Grisham RN. Pre-clinical activity of the oral DNA-PK inhibitor, peposertib (M3814), combined with radiation in xenograft models of cervical cancer. Sci Rep 2022; 12:974. [PMID: 35046420 PMCID: PMC8770623 DOI: 10.1038/s41598-021-04618-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/22/2021] [Indexed: 11/24/2022] Open
Abstract
DNA-dependent protein kinase (DNA-PK) plays a crucial role in repair of DNA double-strand breaks by facilitating non-homologous end-joining. Inhibitors of DNA-PK have the potential to block DNA repair and enhance DNA-damaging agents. Peposertib (M3814) is a DNA-PK inhibitor that has shown preclinical activity in combination with DNA-damaging agents, including ionizing radiation (IR) and topoisomerase II inhibitors. Here we evaluated the activity of peposertib (M3814) in combination with radiation in a mouse xenograft model of HPV-associated cervical cancer. Athymic nude female mice with established tumors derived from HeLa cells injected into the flank were treated with vehicle alone (n = 3), IR alone (n = 4), and peposertib (M38814) in combination with IR (M3814 + IR; n = 4). While IR alone was associated with a trend towards decreased tumor volume compared with untreated, only the M3814 + IR treatment arm was associated with consistent and significant reduction in tumor burden, which correlated with higher levels of γ-H2AX in tumor cells, a marker of double-strand DNA breaks. Our data support further clinical evaluation of the combination of peposertib (M38814) and IR in cervical cancer.
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Affiliation(s)
| | - Beryl Manning-Geist
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christina Henson
- University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Gopa Iyer
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Ginger J Gardner
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Yukio Sonoda
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Weill Cornell Medical College, New York, NY, USA
| | - Kathleen N Moore
- University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Carol Aghajanian
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Weill Cornell Medical College, New York, NY, USA
| | - M Herman Chui
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Rachel N Grisham
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA. .,Weill Cornell Medical College, New York, NY, USA.
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14
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HIF-1 Interacts with TRIM28 and DNA-PK to release paused RNA polymerase II and activate target gene transcription in response to hypoxia. Nat Commun 2022; 13:316. [PMID: 35031618 PMCID: PMC8760265 DOI: 10.1038/s41467-021-27944-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022] Open
Abstract
Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that acts as a regulator of oxygen (O2) homeostasis in metazoan species by binding to hypoxia response elements (HREs) and activating the transcription of hundreds of genes in response to reduced O2 availability. RNA polymerase II (Pol II) initiates transcription of many HIF target genes under non-hypoxic conditions but pauses after approximately 30–60 nucleotides and requires HIF-1 binding for release. Here we report that in hypoxic breast cancer cells, HIF-1 recruits TRIM28 and DNA-dependent protein kinase (DNA-PK) to HREs to release paused Pol II. We show that HIF-1α and TRIM28 assemble the catalytically-active DNA-PK heterotrimer, which phosphorylates TRIM28 at serine-824, enabling recruitment of CDK9, which phosphorylates serine-2 of the Pol II large subunit C-terminal domain as well as the negative elongation factor to release paused Pol II, thereby stimulating productive transcriptional elongation. Our studies reveal a molecular mechanism by which HIF-1 stimulates gene transcription and reveal that the anticancer effects of drugs targeting DNA-PK in breast cancer may be due in part to their inhibition of HIF-dependent transcription. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that modulates target gene expression in response to changes in oxygen availability. Here the authors show that HIF-1 forms a complex with TRIM28 and DNA-dependent protein kinase (DNA-PK) that phosphorylates TRIM28. This leads to CDK9 recruitment, which stimulates RNA polymerase II (RNAPII) pause release and transcriptional elongation.
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15
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Bannik K, Madas B, Jarke S, Sutter A, Siemeister G, Schatz C, Mumberg D, Zitzmann-Kolbe S. DNA repair inhibitors sensitize cells differently to high and low LET radiation. Sci Rep 2021; 11:23257. [PMID: 34853427 PMCID: PMC8636489 DOI: 10.1038/s41598-021-02719-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 11/15/2021] [Indexed: 11/09/2022] Open
Abstract
The aim of this study was to investigate effects of high LET α-radiation in combination with inhibitors of DDR (DNA-PK and ATM) and to compare the effect with the radiosensitizing effect of low LET X-ray radiation. The various cell lines were irradiated with α-radiation and with X-ray. Clonogenic survival, the formation of micronuclei and cell cycle distribution were studied after combining of radiation with DDR inhibitors. The inhibitors sensitized different cancer cell lines to radiation. DNA-PKi affected survival rates in combination with α-radiation in selected cell lines. The sensitization enhancement ratios were in the range of 1.6–1.85 in cancer cells. ATMi sensitized H460 cells and significantly increased the micronucleus frequency for both radiation qualities. ATMi in combination with α-radiation reduced survival of HEK293. A significantly elicited cell cycle arrest in G2/M phase after co-treatment of ATMi with α-radiation and X-ray. The most prominent treatment effect was observed in the HEK293 by combining α-radiation and inhibitions. ATMi preferentially sensitized cancer cells and normal HEK293 cells to α-radiation. DNA-PKi and ATMi can sensitize cancer cells to X-ray, but the effectiveness was dependent on cancer cells itself. α-radiation reduced proliferation in primary fibroblast without G2/M arrest.
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Affiliation(s)
- Kristina Bannik
- Pharmaceuticals Division, Bayer AG, Berlin, Germany.,, Berlin, Germany
| | | | - Sabrina Jarke
- Pharmaceuticals Division, Bayer AG, Berlin, Germany.,Nuvisan-ICB GmbH, Berlin, Germany
| | | | - Gerhard Siemeister
- Pharmaceuticals Division, Bayer AG, Berlin, Germany.,Nuvisan-ICB GmbH, Berlin, Germany
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16
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Chao OS, Goodman OB. DNA-PKc inhibition overcomes taxane resistance by promoting taxane-induced DNA damage in prostate cancer cells. Prostate 2021; 81:1032-1048. [PMID: 34297853 DOI: 10.1002/pros.24200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/15/2021] [Accepted: 07/09/2021] [Indexed: 01/20/2023]
Abstract
BACKGROUND Overcoming taxane resistance remains a major clinical challenge in metastatic castrate-resistant prostate cancer (mCRPC). Loss of DNA repair proteins is associated with resistance to anti-microtubule agents. We propose that alterations in DNA damage response (DDR) pathway contribute to taxane resistance, and identification of these alterations may provide a potential therapeutic target to resensitize docetaxel-refractory mCRPC to taxane-based therapy. METHODS Alterations in DDR gene expression in our prostate cancer cell line model of docetaxel-resistance (DU145-DxR) derived from DU-145 cells were determined by DDR pathway-specific polymerase chain reaction array and immunoblotting. The PRKDC gene encoding DNA-PKc (DNA-dependent protein kinase catalytic unit), was noted to be overexpressed and evaluated for its role in docetaxel resistance. Cell viability and clonogenic survival of docetaxel-treated DU145-DxR cells were assessed after pharmacologic inhibition of DNA-PKc with three different inhibitors-NU7441, LTURM34, and M3814. Response to second-line cytotoxic agents, cabazitaxel and etoposide upon DNA-PKc inhibition was also tested. The impact of DNA-PKc upregulation on DNA damage repair was evaluated by comet assay and analysis of double-strand breaks marker, γH2AX and Rad51. Lastly, DNA-PKc inhibitor's effect on MDR1 activity was assessed by rhodamine 123 efflux assay. RESULTS DDR pathway-specific gene profiling revealed significant upregulation of PRKDC and CDK7, and downregulation of MSH3 in DU145-DxR cells. Compared to parental DU145, DU145-DxR cells sustained significantly less DNA damage when exposed to etoposide and docetaxel. Pharmacologic inhibition of DNA-PKc, a component of NHEJ repair machinery, with all three inhibitors, significantly resensitized DU145-DxR cells to docetaxel. Furthermore, DNA-PKc inhibition also resensitized DU145-DxR to cabazitaxel and etoposide, which demonstrated cross-resistance. Inhibition of DNA-PKc led to increased DNA damage in etoposide- and docetaxel-treated DU145-DxR cells. Finally, DNA-PKc inhibition did not affect MDR1 activity, indicating that DNA-PKc inhibitors resensitized taxane-resistant cells via an MDR1-independent mechanism. CONCLUSION This study supports a role of DDR genes, particularly, DNA-PKc in promoting resistance to taxanes in mCRPC. Targeting prostatic DNA-PKc may provide a novel strategy to restore taxane sensitivity in taxane-refractory mCRPC.
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Affiliation(s)
- Olivia S Chao
- College of Medicine, Roseman University of Health Sciences, Las Vegas, Nevada, USA
| | - Oscar B Goodman
- College of Medicine, Roseman University of Health Sciences, Las Vegas, Nevada, USA
- Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA
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17
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Matsumoto Y, Asa ADDC, Modak C, Shimada M. DNA-Dependent Protein Kinase Catalytic Subunit: The Sensor for DNA Double-Strand Breaks Structurally and Functionally Related to Ataxia Telangiectasia Mutated. Genes (Basel) 2021; 12:genes12081143. [PMID: 34440313 PMCID: PMC8394720 DOI: 10.3390/genes12081143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 11/16/2022] Open
Abstract
The DNA-dependent protein kinase (DNA-PK) is composed of a DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Ku70/Ku80 heterodimer. DNA-PK is thought to act as the “sensor” for DNA double-stranded breaks (DSB), which are considered the most deleterious type of DNA damage. In particular, DNA-PKcs and Ku are shown to be essential for DSB repair through nonhomologous end joining (NHEJ). The phenotypes of animals and human individuals with defective DNA-PKcs or Ku functions indicate their essential roles in these developments, especially in neuronal and immune systems. DNA-PKcs are structurally related to Ataxia–telangiectasia mutated (ATM), which is also implicated in the cellular responses to DSBs. DNA-PKcs and ATM constitute the phosphatidylinositol 3-kinase-like kinases (PIKKs) family with several other molecules. Here, we review the accumulated knowledge on the functions of DNA-PKcs, mainly based on the phenotypes of DNA-PKcs-deficient cells in animals and human individuals, and also discuss its relationship with ATM in the maintenance of genomic stability.
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18
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Cowman S, Pizer B, Sée V. Downregulation of both mismatch repair and non-homologous end-joining pathways in hypoxic brain tumour cell lines. PeerJ 2021; 9:e11275. [PMID: 33986995 PMCID: PMC8092103 DOI: 10.7717/peerj.11275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/24/2021] [Indexed: 01/11/2023] Open
Abstract
Glioblastoma, a grade IV astrocytoma, has a poor survival rate in part due to ineffective treatment options available. These tumours are heterogeneous with areas of low oxygen levels, termed hypoxic regions. Many intra-cellular signalling pathways, including DNA repair, can be altered by hypoxia. Since DNA damage induction and subsequent activation of DNA repair mechanisms is the cornerstone of glioblastoma treatment, alterations to DNA repair mechanisms could have a direct influence on treatment success. Our aim was to elucidate the impact of chronic hypoxia on DNA repair gene expression in a range of glioblastoma cell lines. We adopted a NanoString transcriptomic approach to examine the expression of 180 DNA repair-related genes in four classical glioblastoma cell lines (U87-MG, U251-MG, D566-MG, T98G) exposed to 5 days of normoxia (21% O2), moderate (1% O2) or severe (0.1% O2) hypoxia. We observed altered gene expression in several DNA repair pathways including homologous recombination repair, non-homologous end-joining and mismatch repair, with hypoxia primarily resulting in downregulation of gene expression. The extent of gene expression changes was dependent on hypoxic severity. Some, but not all, of these downregulations were directly under the control of HIF activity. For example, the downregulation of LIG4, a key component of non-homologous end-joining, was reversed upon inhibition of the hypoxia-inducible factor (HIF). In contrast, the downregulation of the mismatch repair gene, PMS2, was not affected by HIF inhibition. This suggests that numerous molecular mechanisms lead to hypoxia-induced reprogramming of the transcriptional landscape of DNA repair. Whilst the global impact of hypoxia on DNA repair gene expression is likely to lead to genomic instability, tumorigenesis and reduced sensitivity to anti-cancer treatment, treatment re-sensitising might require additional approaches to a simple HIF inhibition.
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Affiliation(s)
- Sophie Cowman
- Institute of Systems, Molecular and Integrative Biology, Department of Molecular Physiology and Cell Signalling, University of Liverpool, Liverpool, Merseyside, United Kingdom.,Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt-Lake-City, Utah, United States
| | - Barry Pizer
- Paediatric Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, Merseyside, United Kingdom
| | - Violaine Sée
- Institute of Systems, Molecular and Integrative Biology, Department of Molecular Physiology and Cell Signalling, University of Liverpool, Liverpool, Merseyside, United Kingdom
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19
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Kara A, Özgür A, Nalbantoğlu S, Karadağ A. DNA repair pathways and their roles in drug resistance for lung adenocarcinoma. Mol Biol Rep 2021; 48:3813-3825. [PMID: 33856604 DOI: 10.1007/s11033-021-06314-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/24/2021] [Indexed: 01/24/2023]
Abstract
Lung cancer is the leading cancer type of death rate. The lung adenocarcinoma subtype is responsible for almost half of the total lung cancer deaths. Despite the improvements in cancer treatment in recent years, lung adenocarcinoma patients' overall survival rate remains poor. Immunetherapy and chemotherapy are two of the most widely used options for the treatment of cancer. Although many cancer types initially respond to these treatments, the development of resistance is inevitable. The rapid development of drug resistance mainly characterizes lung adenocarcinoma. Despite being the subject of many studies in recent years, the resistance initiation and progression mechanism is still unclear. In this review, we have examined the role of the primary DNA repair pathways (non-homologous end joining (NHEJ) pathway, homologous-recombinant repair (HR) pathway, base excision repair (BER) pathway, and nucleotide excision repair (NER) pathway and transactivation mechanisms of tumor protein 53 (TP53) in drug resistance development. This review suggests that mentioned pathways have essential roles in developing the resistance against chemotherapy and immunotherapy in lung adenocarcinoma patients.
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Affiliation(s)
- Altan Kara
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey.
| | - Aykut Özgür
- Laboratory and Veterinary Health Program, Department of Veterinary Medicine, Artova Vocational School, Tokat Gaziosmanpaşa University, Tokat, Turkey
| | - Sinem Nalbantoğlu
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey
| | - Abdullah Karadağ
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey
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20
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Yadav P, Pandey VK, Shankar BS. Proteomic analysis of radio-resistant breast cancer xenografts: Increased TGF-β signaling and metabolism. Cell Biol Int 2020; 45:804-819. [PMID: 33325135 DOI: 10.1002/cbin.11525] [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: 06/18/2020] [Revised: 11/16/2020] [Accepted: 12/13/2020] [Indexed: 12/11/2022]
Abstract
Our previous studies have shown that MCF-7 breast cancer cell line exposed to 6 Gy and allowed to recover for 7 days (D7-6G) developed radio-resistance. In this study, we have tested the ability of these cells to form tumors in severe combined immunodeficiency (SCID) mice and characterized these tumors by proteomic analyses. Untreated (MCF-C) and D7-6G cells (MCF-R) were injected s.c. in SCID mice and tumor growth monitored. On Day 18, the mice were killed and tumor tissues were fixed in formalin or RNA later. Expression of genes was assessed by reverse transcription-polymerase chain reaction and proteins by enzyme-linked immunosorbent assay/antibody labeling and flow cytometry. Label free proteomic analyses was carried out by liquid chromatography-mass spectrometry. Metabolic analysis was carried out using Seahorse analyzer. MCF-R cells had a shorter latency and formed larger tumors. These tumors were characterized by an increased expression of transforming growth factor β (TGF-β) isoforms; its downstream genes pSMAD3, Snail-1, Zeb-1, HMGA2; hybrid epithelial/mesenchymal phenotype; migration, enrichment of cancer stem cells and radioresistance following challenge dose of radiation. Proteomic analysis of MCF-7R tumors resulted in identification of a total of 649 differentially expressed proteins and pathway analyses using protein annotation through evolutionary relationship indicated enrichment of genes involved in metabolism. Data are available via ProteomeXchange with identifier PXD022506. Seahorse analyzer confirmed increased metabolism in these cells with increased oxidative phosphorylation as well as glycolysis. Increased uptake of 2-NBDG further confirmed increased glycolysis. In summary, we demonstrate that radioresistant breast cancer cells had an enrichment of TGF-β signaling and increased metabolism.
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Affiliation(s)
- Poonam Yadav
- Radiation Biology & Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Center, Mumbai, Maharastra, India.,Department of Life Sciences, Homi Bhabha National Institute, Mumbai, Maharastra, India
| | - Vipul K Pandey
- Radiation Biology & Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Center, Mumbai, Maharastra, India
| | - Bhavani S Shankar
- Radiation Biology & Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Center, Mumbai, Maharastra, India.,Department of Life Sciences, Homi Bhabha National Institute, Mumbai, Maharastra, India
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21
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Dianhydrogalactitol synergizes with topoisomerase poisons to overcome DNA repair activity in tumor cells. Cell Death Dis 2020; 11:577. [PMID: 32709853 PMCID: PMC7381652 DOI: 10.1038/s41419-020-02780-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/27/2022]
Abstract
1,2:5,6-Dianhydrogalactitol (DAG) is a bi-functional DNA-targeting agent currently in phase II clinical trial for treatment of temozolomide-resistant glioblastoma (GBM). In the present study, we investigated the cytotoxic activity of DAG alone or in combination with common chemotherapy agents in GBM and prostate cancer (PCa) cells, and determined the impact of DNA repair pathways on DAG-induced cytotoxicity. We found that DAG produced replication-dependent DNA lesions decorated with RPA32, RAD51, and γH2AX foci. DAG-induced cytotoxicity was unaffected by MLH1, MSH2, and DNA-PK expression, but was enhanced by knockdown of BRCA1. Acting in S phase, DAG displayed selective synergy with topoisomerase I (camptothecin and irinotecan) and topoisomerase II (etoposide) poisons in GBM, PCa, and lung cancer cells with no synergy observed for docetaxel. Importantly, DAG combined with irinotecan treatment enhanced tumor responses and prolonged survival of tumor-bearing mice. This work provides mechanistic insight into DAG cytotoxicity in GBM and PCa cells and offers a rational for exploring combination regimens with topoisomerase I/II poisons in future clinical trials.
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22
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Nickoloff JA, Sharma N, Taylor L. Clustered DNA Double-Strand Breaks: Biological Effects and Relevance to Cancer Radiotherapy. Genes (Basel) 2020; 11:E99. [PMID: 31952359 PMCID: PMC7017136 DOI: 10.3390/genes11010099] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/08/2020] [Accepted: 01/14/2020] [Indexed: 01/03/2023] Open
Abstract
Cells manage to survive, thrive, and divide with high accuracy despite the constant threat of DNA damage. Cells have evolved with several systems that efficiently repair spontaneous, isolated DNA lesions with a high degree of accuracy. Ionizing radiation and a few radiomimetic chemicals can produce clustered DNA damage comprising complex arrangements of single-strand damage and DNA double-strand breaks (DSBs). There is substantial evidence that clustered DNA damage is more mutagenic and cytotoxic than isolated damage. Radiation-induced clustered DNA damage has proven difficult to study because the spectrum of induced lesions is very complex, and lesions are randomly distributed throughout the genome. Nonetheless, it is fairly well-established that radiation-induced clustered DNA damage, including non-DSB and DSB clustered lesions, are poorly repaired or fail to repair, accounting for the greater mutagenic and cytotoxic effects of clustered lesions compared to isolated lesions. High linear energy transfer (LET) charged particle radiation is more cytotoxic per unit dose than low LET radiation because high LET radiation produces more clustered DNA damage. Studies with I-SceI nuclease demonstrate that nuclease-induced DSB clusters are also cytotoxic, indicating that this cytotoxicity is independent of radiogenic lesions, including single-strand lesions and chemically "dirty" DSB ends. The poor repair of clustered DSBs at least in part reflects inhibition of canonical NHEJ by short DNA fragments. This shifts repair toward HR and perhaps alternative NHEJ, and can result in chromothripsis-mediated genome instability or cell death. These principals are important for cancer treatment by low and high LET radiation.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (N.S.); (L.T.)
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Serrano-Benítez A, Cortés-Ledesma F, Ruiz JF. "An End to a Means": How DNA-End Structure Shapes the Double-Strand Break Repair Process. Front Mol Biosci 2020; 6:153. [PMID: 31998749 PMCID: PMC6965357 DOI: 10.3389/fmolb.2019.00153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/11/2019] [Indexed: 12/12/2022] Open
Abstract
Endogenously-arising DNA double-strand breaks (DSBs) rarely harbor canonical 5′-phosphate, 3′-hydroxyl moieties at the ends, which are, regardless of the pathway used, ultimately required for their repair. Cells are therefore endowed with a wide variety of enzymes that can deal with these chemical and structural variations and guarantee the formation of ligatable termini. An important distinction is whether the ends are directly “unblocked” by specific enzymatic activities without affecting the integrity of the DNA molecule and its sequence, or whether they are “processed” by unspecific nucleases that remove nucleotides from the termini. DNA end structure and configuration, therefore, shape the repair process, its requirements, and, importantly, its final outcome. Thus, the molecular mechanisms that coordinate and integrate the cellular response to blocked DSBs, although still largely unexplored, can be particularly relevant for maintaining genome integrity and avoiding malignant transformation and cancer.
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Affiliation(s)
- Almudena Serrano-Benítez
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER-CSIC-University of Seville-Pablo de Olavide University), Seville, Spain
| | - Felipe Cortés-Ledesma
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER-CSIC-University of Seville-Pablo de Olavide University), Seville, Spain.,Topology and DNA breaks Group, Spanish National Cancer Research Center, Madrid, Spain
| | - Jose F Ruiz
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER-CSIC-University of Seville-Pablo de Olavide University), Seville, Spain.,Department of Plant Biochemistry and Molecular Biology, University of Seville, Seville, Spain
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24
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Willoughby CE, Jiang Y, Thomas HD, Willmore E, Kyle S, Wittner A, Phillips N, Zhao Y, Tudhope SJ, Prendergast L, Junge G, Lourenco LM, Finlay MRV, Turner P, Munck JM, Griffin RJ, Rennison T, Pickles J, Cano C, Newell DR, Reeves HL, Ryan AJ, Wedge SR. Selective DNA-PKcs inhibition extends the therapeutic index of localized radiotherapy and chemotherapy. J Clin Invest 2020; 130:258-271. [PMID: 31581151 PMCID: PMC6934184 DOI: 10.1172/jci127483] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 09/25/2019] [Indexed: 11/23/2022] Open
Abstract
Potentiating radiotherapy and chemotherapy by inhibiting DNA damage repair is proposed as a therapeutic strategy to improve outcomes for patients with solid tumors. However, this approach risks enhancing normal tissue toxicity as much as tumor toxicity, thereby limiting its translational impact. Using NU5455, a newly identified highly selective oral inhibitor of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) activity, we found that it was indeed possible to preferentially augment the effect of targeted radiotherapy on human orthotopic lung tumors without influencing acute DNA damage or a late radiation-induced toxicity (fibrosis) to normal mouse lung. Furthermore, while NU5455 administration increased both the efficacy and the toxicity of a parenterally administered topoisomerase inhibitor, it enhanced the activity of doxorubicin released locally in liver tumor xenografts without inducing any adverse effect. This strategy is particularly relevant to hepatocellular cancer, which is treated clinically with localized drug-eluting beads and for which DNA-PKcs activity is reported to confer resistance to treatment. We conclude that transient pharmacological inhibition of DNA-PKcs activity is effective and tolerable when combined with localized DNA-damaging therapies and thus has promising clinical potential.
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Affiliation(s)
- Catherine E. Willoughby
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yanyan Jiang
- Cancer Research UK and UK Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Huw D. Thomas
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Elaine Willmore
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Suzanne Kyle
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anita Wittner
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nicole Phillips
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yan Zhao
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Susan J. Tudhope
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lisa Prendergast
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gesa Junge
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Luiza Madia Lourenco
- Cancer Research UK and UK Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - M. Raymond V. Finlay
- Medicinal Chemistry, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | - Paul Turner
- Medicinal Chemistry, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | | | - Roger J. Griffin
- Cancer Research UK Newcastle Drug Discovery Unit, Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tommy Rennison
- Cancer Research UK Newcastle Drug Discovery Unit, Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - James Pickles
- Cancer Research UK Newcastle Drug Discovery Unit, Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Celine Cano
- Cancer Research UK Newcastle Drug Discovery Unit, Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David R. Newell
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Helen L. Reeves
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- Hepatopancreatobiliary Multidisciplinary Team, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Anderson J. Ryan
- Cancer Research UK and UK Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Stephen R. Wedge
- Cancer Research UK Newcastle Drug Discovery Unit, Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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25
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Scutts SR, Ember SW, Ren H, Ye C, Lovejoy CA, Mazzon M, Veyer DL, Sumner RP, Smith GL. DNA-PK Is Targeted by Multiple Vaccinia Virus Proteins to Inhibit DNA Sensing. Cell Rep 2019; 25:1953-1965.e4. [PMID: 30428360 PMCID: PMC6250978 DOI: 10.1016/j.celrep.2018.10.034] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/26/2018] [Accepted: 10/05/2018] [Indexed: 12/16/2022] Open
Abstract
Virus infection is sensed by pattern recognition receptors (PRRs) detecting virus nucleic acids and initiating an innate immune response. DNA-dependent protein kinase (DNA-PK) is a PRR that binds cytosolic DNA and is antagonized by vaccinia virus (VACV) protein C16. Here, VACV protein C4 is also shown to antagonize DNA-PK by binding to Ku and blocking Ku binding to DNA, leading to a reduced production of cytokines and chemokines in vivo and a diminished recruitment of inflammatory cells. C4 and C16 share redundancy in that a double deletion virus has reduced virulence not seen with single deletion viruses following intradermal infection. However, non-redundant functions exist because both single deletion viruses display attenuated virulence compared to wild-type VACV after intranasal infection. It is notable that VACV expresses two proteins to antagonize DNA-PK, but it is not known to target other DNA sensors, emphasizing the importance of this PRR in the response to infection in vivo. DNA-PK is a pattern recognition receptor that binds cytosolic DNA Vaccinia virus proteins C4 and C16 antagonize DNA-PK by blocking DNA binding C4 and C16 inhibit IRF3 signaling, cytokine production, and immune cell recruitment C4 and C16 share redundant and non-redundant functions in vivo
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Affiliation(s)
- Simon R Scutts
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Stuart W Ember
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Hongwei Ren
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Chao Ye
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Christopher A Lovejoy
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Michela Mazzon
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - David L Veyer
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Rebecca P Sumner
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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26
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Zhang B, Wu H, Hao J, Wu Y, Yang B. Inhibition of DNA-PKcs activity re-sensitizes uveal melanoma cells to radio- and chemotherapy. Biochem Biophys Res Commun 2019; 522:639-646. [PMID: 31785810 DOI: 10.1016/j.bbrc.2019.11.133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 11/20/2019] [Indexed: 02/06/2023]
Abstract
Uveal melanoma (UM) is the most common primary intraocular tumor in adults. Despite of important progress in the local therapy, high radioresistance in primary tumor and chemoresistance in metastatic disease are the major obstacles for UM therapy. Therefore, strategies to overcome resistance to radiation or chemotherapy in UM are urgently needed. In this study, we found that phosphorylation of DNA-PKcs, which is the key factor of non-homologous end joining (NHEJ) pathway, was remarkably overexpressed in ionizing radiation (IR)- and Selumetinib resistant UM cells. Increased amount of NHEJ events were also observed in resistant UM cells. Inhibition of DNA-PKcs by NU7441 significantly impaired DNA repair and re-sensitized resistant UM cells to radiation and Selumetinib both in vitro and in vivo. The results demonstrate increased DNA double strand break repair as a mechanism of resistance to ionizing radiation and Selumetinib, and identify DNA-PKcs as a promising target for radio-and chemotherapy in UM patients.
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Affiliation(s)
- Bingjie Zhang
- Department of Ophthalmology, First Hospital of Jilin University, Changchun, China.
| | - Haiyan Wu
- Department of Ophthalmology, Songyuan Central Hospital, Songyuan, China.
| | - Jilong Hao
- Department of Ophthalmology, First Hospital of Jilin University, Changchun, China.
| | - Yunlong Wu
- Department of Ophthalmology, First Hospital of Jilin University, Changchun, China.
| | - Ben Yang
- China-Japan Union Hospital of Jilin University, Changchun, China.
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27
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AZD7648 is a potent and selective DNA-PK inhibitor that enhances radiation, chemotherapy and olaparib activity. Nat Commun 2019; 10:5065. [PMID: 31699977 PMCID: PMC6838110 DOI: 10.1038/s41467-019-12836-9] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/04/2019] [Indexed: 02/05/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) is a critical player in the DNA damage response (DDR) and instrumental in the non-homologous end-joining pathway (NHEJ) used to detect and repair DNA double-strand breaks (DSBs). We demonstrate that the potent and highly selective DNA-PK inhibitor, AZD7648, is an efficient sensitizer of radiation- and doxorubicin-induced DNA damage, with combinations in xenograft and patient-derived xenograft (PDX) models inducing sustained regressions. Using ATM-deficient cells, we demonstrate that AZD7648, in combination with the PARP inhibitor olaparib, increases genomic instability, resulting in cell growth inhibition and apoptosis. AZD7648 enhanced olaparib efficacy across a range of doses and schedules in xenograft and PDX models, enabling sustained tumour regression and providing a clear rationale for its clinical investigation. Through its differentiated mechanism of action as an NHEJ inhibitor, AZD7648 complements the current armamentarium of DDR-targeted agents and has potential in combination with these agents to achieve deeper responses to current therapies. DNA-dependent protein kinase (DNA-PK) plays a major role in the DNA damage response upon double-strand break formation. Here, the authors show that the DNA-PK inhibitor AZD7648, enhances the activity of radiotherapy, chemotherapy and the PARP inhibitor olaparib in multiple mouse tumour models.
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28
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Lu H, Saha J, Beckmann PJ, Hendrickson EA, Davis AJ. DNA-PKcs promotes chromatin decondensation to facilitate initiation of the DNA damage response. Nucleic Acids Res 2019; 47:9467-9479. [PMID: 31396623 PMCID: PMC6765147 DOI: 10.1093/nar/gkz694] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 11/14/2022] Open
Abstract
The DNA damage response (DDR) encompasses the cellular response to DNA double-stranded breaks (DSBs), and includes recognition of the DSB, recruitment of numerous factors to the DNA damage site, initiation of signaling cascades, chromatin remodeling, cell-cycle checkpoint activation, and repair of the DSB. Key drivers of the DDR are multiple members of the phosphatidylinositol 3-kinase-related kinase family, including ataxia telangiectasia mutated (ATM), ataxia telangiectasia and Rad3-related (ATR), and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). ATM and ATR modulate multiple portions of the DDR, but DNA-PKcs is believed to primarily function in the DSB repair pathway, non-homologous end joining. Utilizing a human cell line in which the kinase domain of DNA-PKcs is inactivated, we show here that DNA-PKcs kinase activity is required for the cellular response to DSBs immediately after their induction. Specifically, DNA-PKcs kinase activity initiates phosphorylation of the chromatin factors H2AX and KAP1 following ionizing radiation exposure and drives local chromatin decondensation near the DSB site. Furthermore, loss of DNA-PKcs kinase activity results in a marked decrease in the recruitment of numerous members of the DDR machinery to DSBs. Collectively, these results provide clear evidence that DNA-PKcs activity is pivotal for the initiation of the DDR.
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Affiliation(s)
- Huiming Lu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Janapriya Saha
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pauline J Beckmann
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Anthony J Davis
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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29
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Liu Y, Efimova EV, Ramamurthy A, Kron SJ. Repair-independent functions of DNA-PKcs protect irradiated cells from mitotic slippage and accelerated senescence. J Cell Sci 2019; 132:jcs229385. [PMID: 31189537 PMCID: PMC6633392 DOI: 10.1242/jcs.229385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/27/2019] [Indexed: 12/21/2022] Open
Abstract
The binding of DNA-dependent protein kinase catalytic subunit (DNA-PKcs, also known as PRKDC) to Ku proteins at DNA double-strand breaks (DSBs) has long been considered essential for non-homologous end joining (NHEJ) repair, providing a rationale for use of DNA-PKcs inhibitors as cancer therapeutics. Given lagging clinical translation, we reexamined mechanisms and observed instead that DSB repair can proceed independently of DNA-PKcs. While repair of radiation-induced DSBs was blocked in cells expressing shRNAs targeting Ku proteins or other NHEJ core factors, DSBs were repaired on schedule despite targeting DNA-PKcs. Although we failed to observe a DSB repair defect, the γH2AX foci that formed at sites of DNA damage persisted indefinitely after irradiation, leading to cytokinesis failure and accumulation of binucleated cells. Following this mitotic slippage, cells with decreased DNA-PKcs underwent accelerated cellular senescence. We identified downregulation of ataxia-telangiectasia mutated kinase (ATM) as the critical role of DNA-PKcs in recovery from DNA damage, insofar as targeting ATM restored γH2AX foci resolution and cytokinesis. Considering the lack of direct impact on DSB repair and emerging links between senescence and resistance to cancer therapy, these results suggest reassessing DNA-PKcs as a target for cancer treatment.
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Affiliation(s)
- Yue Liu
- Department of Molecular Genetics and Cell Biology and Ludwig Center for Metastasis Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Elena V Efimova
- Department of Molecular Genetics and Cell Biology and Ludwig Center for Metastasis Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Aishwarya Ramamurthy
- Department of Molecular Genetics and Cell Biology and Ludwig Center for Metastasis Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Stephen J Kron
- Department of Molecular Genetics and Cell Biology and Ludwig Center for Metastasis Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
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30
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Geng W, Tian D, Wang Q, Shan S, Zhou J, Xu W, Shan H. DNA‑PKcs inhibitor increases the sensitivity of gastric cancer cells to radiotherapy. Oncol Rep 2019; 42:561-570. [PMID: 31173270 PMCID: PMC6610038 DOI: 10.3892/or.2019.7187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 05/23/2019] [Indexed: 12/15/2022] Open
Abstract
Gastric cancer (GC) is a severe public health problem worldwide, particularly in China. Radiotherapy is the main locoregional treatment for various types of unresectable tumor, including GC. However, many patients fail to respond to radiotherapy due to the intrinsic radioresistance of cancer cells. This study was designed to investigate the effects and potential mechanism of radiosensitization associated with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) inhibitor in human GC cell lines in vitro. Among the six GC cell lines (SGC7901, HGC-27, MKN45, MKN74, BGC823 and MGC803) that were exposed to increasing doses of IR (0, 2, 4, 6 and 8 Gy), the mean lethal dose and quasi-threshold dose measurements indicated that BGC823 and MGC803 were relatively insensitive to ionizing radiation (IR). IR induced significant elevation of γ H2A histone family member X (γH2AX) in MKN45 cells compared with BGC823 cells. DNA-PKcs and phospho-DNA-PKcs protein levels were increased in BGC823 and MGC803 cells compared with other GC cell lines (SGC7901, HGC-27, MKN45 and MKN74). DNA-PKcs inhibition led to increased sensitivity of BGC823 and MGC803 cells to IR. NU7441 increased γH2AX expression in the nuclei of BGC823 cells following IR. Combination of DNA-PKcs and CK2 inhibition further increased the sensitivity of GC cells to IR. The combination of NU7441 and CX4945 increased γH2AX expression in the nucleus of BGC823 cells following IR compared with treatment with NU7441 alone. Taken together, the findings suggest that DNA-PKcs inhibitor increased the sensitivity of radioresistant BGC823 and MGC803 cells to radiotherapy through the cleaved-caspase3/γH2AX signaling pathway, thus presenting a potential treatment method for GC.
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Affiliation(s)
- Wei Geng
- Yancheng City No. 1 People's Hospital, Yancheng, Jiangsu 224005, P.R. China
| | - Dalong Tian
- Yancheng City No. 1 People's Hospital, Yancheng, Jiangsu 224005, P.R. China
| | - Qiang Wang
- Department of Molecular Cell Biology and Toxicology, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu 211166, P.R. China
| | - Shunlin Shan
- Yancheng City No. 1 People's Hospital, Yancheng, Jiangsu 224005, P.R. China
| | - Jianwei Zhou
- Cancer Center of The 82nd Hospital of PLA, Huaian, Jiangsu 223001, P.R. China
| | - Wenxia Xu
- Department of Molecular Cell Biology and Toxicology, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu 211166, P.R. China
| | - Husheng Shan
- Cancer Center of The 82nd Hospital of PLA, Huaian, Jiangsu 223001, P.R. China
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31
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Plugged into the Ku-DNA hub: The NHEJ network. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:62-76. [PMID: 30851288 DOI: 10.1016/j.pbiomolbio.2019.03.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 12/16/2022]
Abstract
In vertebrates, double-strand breaks in DNA are primarily repaired by Non-Homologous End-Joining (NHEJ). The ring-shaped Ku heterodimer rapidly senses and threads onto broken DNA ends forming a recruiting hub. Through protein-protein contacts eventually reinforced by protein-DNA interactions, the Ku-DNA hub attracts a series of specialized proteins with scaffolding and/or enzymatic properties. To shed light on these dynamic interplays, we review here current knowledge on proteins directly interacting with Ku and on the contact points involved, with a particular accent on the different classes of Ku-binding motifs identified in several Ku partners. An integrated structural model of the core NHEJ network at the synapsis step is proposed.
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32
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Alnajjar KS, Sweasy JB. A new perspective on oxidation of DNA repair proteins and cancer. DNA Repair (Amst) 2019; 76:60-69. [PMID: 30818170 DOI: 10.1016/j.dnarep.2019.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/07/2019] [Indexed: 02/07/2023]
Abstract
Reactive oxygen and nitrogen species (RONS) are formed as byproducts of many endogenous cellular processes, in response to infections, and upon exposure to various environmental factors. An increase in RONS can saturate the antioxidation system and leads to oxidative stress. Consequently, macromolecules are targeted for oxidative modifications, including DNA and protein. The oxidation of DNA, which leads to base modification and formation of abasic sites along with single and double strand breaks, has been extensively investigated. Protein oxidation is often neglected and is only recently being recognized as an important regulatory mechanism of various DNA repair proteins. This is a review of the current state of research on the regulation of DNA repair by protein oxidation with emphasis on the correlation between inflammation and cancer.
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Affiliation(s)
- Khadijeh S Alnajjar
- Department of Therapeutic Radiology and Department of Genetics, Yale University School of Medicine, New Haven, CT, 06520, United States.
| | - Joann B Sweasy
- Department of Therapeutic Radiology and Department of Genetics, Yale University School of Medicine, New Haven, CT, 06520, United States
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33
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Neal JA, Meek K. Deciphering phenotypic variance in different models of DNA-PKcs deficiency. DNA Repair (Amst) 2018; 73:7-16. [PMID: 30409670 DOI: 10.1016/j.dnarep.2018.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/09/2018] [Accepted: 10/14/2018] [Indexed: 02/02/2023]
Abstract
DNA-PKcs deficiency has been studied in numerous animal models and cell culture systems. In previous studies of kinase inactivating mutations in cell culture systems, ablation of DNA-PK's catalytic activity results in a cell phenotype that is virtually indistinguishable from that ascribed to complete loss of the enzyme. However, a recent compelling study demonstrates a remarkably more severe phenotype in mice harboring a targeted disruption of DNA-PK's ATP binding site as compared to DNA-PKcs deficient mice. Here we investigate the mechanism for these divergent results. We find that kinase inactivating DNA-PKcs mutants markedly radiosensitize immortalized DNA-PKcs deficient cells, but have no substantial effects on transformed DNA-PKcs deficient cells. Since the non-homologous end joining mechanism likely functions similarly in all of these cell strains, it seems unlikely that kinase inactive DNA-PK could impair the end joining mechanism in some cell types, but not in others. In fact, we observed no significant differences in either episomal or chromosomal end joining assays in cells expressing kinase inactivated DNA-PKcs versus no DNA-PKcs. Several potential explanations could explain these data including a non-catalytic role for DNA-PKcs in promoting cell death, or alteration of gene expression by loss of DNA-PKcs as opposed to inhibition of its catalytic activity. Finally, controversy exists as to whether DNA-PKcs autophosphorylates or is the target of other PIKKs; we present data demonstrating that DNA-PK primarily autophosphorylates.
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Affiliation(s)
- Jessica A Neal
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, and Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, and Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA.
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34
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Stringer JM, Winship A, Liew SH, Hutt K. The capacity of oocytes for DNA repair. Cell Mol Life Sci 2018; 75:2777-2792. [PMID: 29748894 PMCID: PMC11105623 DOI: 10.1007/s00018-018-2833-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/27/2018] [Accepted: 05/02/2018] [Indexed: 12/18/2022]
Abstract
Female fertility and offspring health are critically dependent on the maintenance of an adequate supply of high-quality oocytes. Like somatic cells, oocytes are subject to a variety of different types of DNA damage arising from endogenous cellular processes and exposure to exogenous genotoxic stressors. While the repair of intentionally induced DNA double strand breaks in gametes during meiotic recombination is well characterised, less is known about the ability of oocytes to repair pathological DNA damage and the relative contribution of DNA repair to oocyte quality is not well defined. This review will discuss emerging data suggesting that oocytes are in fact capable of efficient DNA repair and that DNA repair may be an important mechanism for ensuring female fertility, as well as the transmission of high-quality genetic material to subsequent generations.
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Affiliation(s)
- Jessica M Stringer
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Amy Winship
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Seng H Liew
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Karla Hutt
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
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The Human T-Cell Leukemia Virus Type 1 Basic Leucine Zipper Factor Attenuates Repair of Double-Stranded DNA Breaks via Nonhomologous End Joining. J Virol 2018; 92:JVI.00672-18. [PMID: 29769340 DOI: 10.1128/jvi.00672-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 05/10/2018] [Indexed: 12/27/2022] Open
Abstract
Adult T-cell leukemia (ATL) is a fatal malignancy of CD4+ T cells infected with human T-cell leukemia virus type 1 (HTLV-1). ATL cells often exhibit random gross chromosomal rearrangements that are associated with the induction and improper repair of double-stranded DNA breaks (DSBs). The viral oncoprotein Tax has been reported to impair DSB repair but has not been shown to be consistently expressed throughout all phases of infection. The viral oncoprotein HTLV-1 basic leucine zipper (bZIP) factor (HBZ) is consistently expressed prior to and throughout disease progression, but it is unclear whether it also influences DSB repair. We report that HBZ attenuates DSB repair by nonhomologous end joining (NHEJ), in a manner dependent upon the bZIP domain. HBZ was found to interact with two vital members of the NHEJ core machinery, Ku70 and Ku80, and to be recruited to DSBs in a bZIP-dependent manner in vitro We observed that HBZ expression also resulted in a bZIP-dependent delay in DNA protein kinase (DNA-PK) activation following treatment with etoposide. Although Tax is reported to interact with Ku70, we did not find Tax expression to interfere with HBZ:Ku complex formation. However, as Tax was reported to saturate NHEJ, we found that this effect masked the attenuation of NHEJ by HBZ. Overall, these data suggest that DSB repair mechanisms are impaired not only by Tax but also by HBZ and show that HBZ expression may significantly contribute to the accumulation of chromosomal abnormalities during HTLV-1-mediated oncogenesis.IMPORTANCE Human T-cell leukemia virus type 1 (HTLV-1) infects 15 million to 20 million people worldwide. Approximately 90% of infected individuals are asymptomatic and may remain undiagnosed, increasing the risk that they will unknowingly transmit the virus. About 5% of the HTLV-1-positive population develop adult T-cell leukemia (ATL), a fatal disease that is not highly responsive to treatment. Although ATL development remains poorly understood, two viral proteins, Tax and HBZ, have been implicated in driving disease progression by manipulating host cell signaling and transcriptional pathways. Unlike Tax, HBZ expression is consistently observed in all infected individuals, making it important to elucidate the specific role of HBZ in disease progression. Here, we present evidence that HBZ could promote the accumulation of double-stranded DNA breaks (DSBs) through the attenuation of the nonhomologous end joining (NHEJ) repair pathway. This effect may lead to genome instability, ultimately contributing to the development of ATL.
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Paquin KL, Howlett NG. Understanding the Histone DNA Repair Code: H4K20me2 Makes Its Mark. Mol Cancer Res 2018; 16:1335-1345. [PMID: 29858375 DOI: 10.1158/1541-7786.mcr-17-0688] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/28/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022]
Abstract
Chromatin is a highly compact structure that must be rapidly rearranged in order for DNA repair proteins to access sites of damage and facilitate timely and efficient repair. Chromatin plasticity is achieved through multiple processes, including the posttranslational modification of histone tails. In recent years, the impact of histone posttranslational modification on the DNA damage response has become increasingly well recognized, and chromatin plasticity has been firmly linked to efficient DNA repair. One particularly important histone posttranslational modification process is methylation. Here, we focus on the regulation and function of H4K20 methylation (H4K20me) in the DNA damage response and describe the writers, erasers, and readers of this important chromatin mark as well as the combinatorial histone posttranslational modifications that modulate H4K20me recognition. Finally, we discuss the central role of H4K20me in determining if DNA double-strand breaks (DSB) are repaired by the error-prone, nonhomologous DNA end joining pathway or the error-free, homologous recombination pathway. This review article discusses the regulation and function of H4K20me2 in DNA DSB repair and outlines the components and modifications that modulate this important chromatin mark and its fundamental impact on DSB repair pathway choice. Mol Cancer Res; 16(9); 1335-45. ©2018 AACR.
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Affiliation(s)
- Karissa L Paquin
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island
| | - Niall G Howlett
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island.
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Liu X, Li P, Hirayama R, Niu Y, Liu X, Chen W, Jin X, Zhang P, Ye F, Zhao T, Liu B, Li Q. Genistein sensitizes glioblastoma cells to carbon ions via inhibiting DNA-PKcs phosphorylation and subsequently repressing NHEJ and delaying HR repair pathways. Radiother Oncol 2018; 129:84-94. [PMID: 29685705 DOI: 10.1016/j.radonc.2018.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/22/2018] [Accepted: 04/04/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE Previously, we found genistein could sensitize cancer cells to low linear energy transfer (LET) X-rays via inhibiting DNA-PKcs activities. Especially, high-LET heavy ion produces more DNA double strand breaks (DSBs) than low-LET radiation. Thus, the study was designed to investigate the detailed molecular mechanisms of genistein on sensitizing cancer cells to heavy ions. MATERIALS AND METHODS Human glioblastoma (GBM) cell lines with or without genistein pre-treatment were irradiated with high-LET carbon ions. Cell survival was determined with colony formation assay. DNA DSBs were evaluated by means of detecting γ-H2AX foci and immuno-blotting DSB repair proteins, cell apoptosis was detected using Annexin V and PI staining. The interaction of genistein with DNA-PKcs activation site was estimated by molecular docking in the autodock software. RESULTS Genistein sensitized DNA-PKcs proficient GBM cells to high-LET carbon ions via delaying the clearance of γ-H2AX foci. Genistein was physically bound to DNA-PKcs and functionally inhibited the phosphorylation of DNA-PKcs. Consequently, the non-homologous end joining (NHEJ) repair of DSBs was inhibited and the homologous recombination (HR) repair was delayed by genistein, thereby leading to an increase in apoptosis in DNA-PKcs proficient GBM cells after irradiation. CONCLUSION Our study demonstrated that genistein holds promise as a radiosensitizer for enhancing the efficacy of carbon ion radiotherapy against DNA-PKcs proficient GBM via inhibiting DNA-PKcs phosphorylation and subsequently repressing NHEJ and delaying HR repair pathways.
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Affiliation(s)
- Xiongxiong Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ping Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ryoichi Hirayama
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Yuzhen Niu
- Shandong Provincial Research Center for Bioinformatic Engineering and Technique, School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Xinguo Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Weiqiang Chen
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Xiaodong Jin
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Pengcheng Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fei Ye
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Ting Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China
| | - Bingtao Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, China.
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Adamowicz M, d'Adda di Fagagna F, Vermezovic J. NOTCH1 modulates activity of DNA-PKcs. Mutat Res 2018; 808:20-27. [PMID: 29482073 DOI: 10.1016/j.mrfmmm.2018.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 01/13/2018] [Indexed: 11/18/2022]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) controls one of the most frequently used DNA repair pathways in a cell, the non-homologous end joining (NHEJ) pathway. However, the exact role of DNA-PKcs in NHEJ remains poorly defined. Here we show that NOTCH1 attenuates DNA-PKcs-mediated autophosphorylation, as well as the phosphorylation of its specific substrate XRCC4. Surprisingly, NOTCH1-expressing cells do not display any significant impairment in the DNA damage repair, nor cellular survival, and remain sensitive to small molecule DNA-PKcs inhibitor. Additionally, in vitro DNA-PKcs kinase assay shows that NOTCH1 does not inhibit DNA-PKcs kinase activity, implying that NOTCH1 acts on DNA-PKcs through a different mechanism. Together, our set of results suggests that NOTCH1 is a physiological modulator of DNA-PKcs, and that it can be a useful tool to clarify the mechanisms by which DNA-PKcs governs NHEJ DNA repair.
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Affiliation(s)
- Marek Adamowicz
- IFOM Foundation - FIRC Institute of Molecular Oncology Foundation, 20139 Milan, Italy; Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK.
| | - Fabrizio d'Adda di Fagagna
- IFOM Foundation - FIRC Institute of Molecular Oncology Foundation, 20139 Milan, Italy; Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, 27100 Pavia, Italy
| | - Jelena Vermezovic
- IFOM Foundation - FIRC Institute of Molecular Oncology Foundation, 20139 Milan, Italy.
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Chowdhury FA, Hossain MK, Mostofa AGM, Akbor MM, Bin Sayeed MS. Therapeutic Potential of Thymoquinone in Glioblastoma Treatment: Targeting Major Gliomagenesis Signaling Pathways. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4010629. [PMID: 29651429 PMCID: PMC5831880 DOI: 10.1155/2018/4010629] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 12/27/2017] [Indexed: 02/06/2023]
Abstract
Glioblastoma multiforme (GBM) is one of the most devastating brain tumors with median survival of one year and presents unique challenges to therapy because of its aggressive behavior. Current treatment strategy involves surgery, radiotherapy, immunotherapy, and adjuvant chemotherapy even though optimal management requires a multidisciplinary approach and knowledge of potential complications from both the disease and its treatment. Thymoquinone (TQ), the main bioactive component of Nigella sativa L., has exhibited anticancer effects in numerous preclinical studies. Due to its multitargeting nature, TQ interferes in a wide range of tumorigenic processes and counteract carcinogenesis, malignant growth, invasion, migration, and angiogenesis. TQ can specifically sensitize tumor cells towards conventional cancer treatments and minimize therapy-associated toxic effects in normal cells. Its potential to enter brain via nasal pathway due to volatile nature of TQ adds another advantage in overcoming blood-brain barrier. In this review, we summarized the potential role of TQ in different signaling pathways in GBM that have undergone treatment with standard therapeutic modalities or with TQ. Altogether, we suggest further comprehensive evaluation of TQ in preclinical and clinical level to delineate its implied utility as novel therapeutics to combat the challenges for the treatment of GBM.
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Affiliation(s)
- Fabliha Ahmed Chowdhury
- Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Md Kamal Hossain
- Department of Pharmaceutical Chemistry, University of Dhaka, Dhaka 1000, Bangladesh
| | - A. G. M. Mostofa
- Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Maruf Mohammad Akbor
- Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Dhaka 1000, Bangladesh
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Holly JMP, Broadhurst J, Mansor R, Bahl A, Perks CM. Hyperglycemia Promotes TMPRSS2-ERG Gene Fusion in Prostate Cancer Cells via Upregulating Insulin-Like Growth Factor-Binding Protein-2. Front Endocrinol (Lausanne) 2017; 8:305. [PMID: 29163372 PMCID: PMC5681733 DOI: 10.3389/fendo.2017.00305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/20/2017] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Epidemiologic evidence shows that obesity is associated with a greater risk of aggressive prostate cancer (PCa) and PCa-specific mortality and this is observed mainly in men with the TMPRSS2-ERG gene fusion. Obesity is often associated with comorbid conditions such as type 2 diabetes and hyperglycemia: we investigated whether some of the exposures associated with disturbed metabolism can also affect the frequency of this gene fusion. METHODS Fusion was induced in LNCaP PCa cells in normal or high levels of glucose, with or without insulin-like growth factor binding protein-2 (IGFBP-2) silenced or the presence of insulin-like growth factor-1 (IGF-I), insulin, or epidermal growth factor (EGF). RNA was extracted for analysis by nested PCR. Abundance of IGFBP-2, γH2AX, DNA-dependent protein kinase catalytic subunit (DNAPKcs), and β-actin were analyzed by Western immunoblotting. RESULTS Our data suggest that hyperglycemia-induced IGFBP-2 increased the frequency of the gene fusion that was accompanied by decreased levels of DNAPKcs implying that they were mediated by alterations in the rate of repair of double-strand breaks. In contrast insulin, IGF-I and EGF all decreased gene fusion events. CONCLUSION These novel observations may represent a further mechanism by which obesity can exert an effect aggravating PCa progression.
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Affiliation(s)
- Jeff M. P. Holly
- IGFs & Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, Bristol, United Kingdom
| | - Jessica Broadhurst
- IGFs & Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, Bristol, United Kingdom
| | - Rehanna Mansor
- IGFs & Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, Bristol, United Kingdom
| | - Amit Bahl
- Department of Clinical Oncology, Bristol Haematology and Oncology Centre, University Hospitals Bristol, Bristol, United Kingdom
| | - Claire M. Perks
- IGFs & Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, Bristol, United Kingdom
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Akt1 and Akt3 but not Akt2 through interaction with DNA-PKcs stimulate proliferation and post-irradiation cell survival of K-RAS-mutated cancer cells. Cell Death Discov 2017; 3:17072. [PMID: 29090098 PMCID: PMC5661268 DOI: 10.1038/cddiscovery.2017.72] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/18/2017] [Indexed: 01/30/2023] Open
Abstract
Akt1 through the C-terminal domain interacts with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and stimulates the repair of DNA double-strand breaks (DSBs) in K-RAS-mutated (K-RASmut) cells. We investigated the interactions of distinct domain(s) of DNA-PKcs in binding to full-length Akt1. Similarly, we analyzed potential interactions of DNA-PKcs with Akt2 and Akt3. Finally the effect of Akt isoforms in cell proliferation and tumor growth was tested. We demonstrated that Akt1 preferentially binds to the N-terminal domain of DNA-PKcs using pull-down studies with distinct eGFP-tagged DNA-PKcs fragments that were expressed by plasmids in combination with mCherry-tagged full-length Akt isoforms. These binding studies also indicated an interaction with the intermediate and C-terminal domains of DNA-PKcs. In contrast, Akt3 interacted with all four DNA-PKcs fragments without a marked preference for any specific domain. Notably, we could not see binding of Akt2 to any of the tested DNA-PKcs fragments. In subsequent studies, we demonstrated that Akt inhibition interferes with binding of Akt1 to the N-terminal domain of DNA-PKcs. This indicated a correlation between Akt1 activity and the Akt1/DNA-PKcs complex formation. Finally, knockdown studies revealed that the depletion of endogenous Akt1 and Akt3, but not Akt2, inhibit clonogenic activity and repair of ionizing radiation (IR)-induced DNA DSBs, leading to radiosensitization. Furthermore, in a xenograft study the expression of shAkt1 or shAkt3, but not shAkt2 in K-RASmut breast cancer cell line MDA-MB-231 showed major tumor growth delay. Together, these data indicate that Akt1 and Akt3, but not Akt2, physically interact with DNA-PKcs, thus stimulating the repair of DSBs and therefore protecting K-RASmut cells against IR. Likewise, interaction of Akt isoforms with DNA-PKcs could be crucial for their role in regulating tumor growth.
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Cryo-EM structure of human DNA-PK holoenzyme. Cell Res 2017; 27:1341-1350. [PMID: 28840859 DOI: 10.1038/cr.2017.110] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/22/2017] [Accepted: 07/27/2017] [Indexed: 02/07/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) is a serine/threonine protein kinase complex composed of a catalytic subunit (DNA-PKcs) and KU70/80 heterodimer bound to DNA. DNA-PK holoenzyme plays a critical role in non-homologous end joining (NHEJ), the major DNA repair pathway. Here, we determined cryo-electron microscopy structure of human DNA-PK holoenzyme at 6.6 Å resolution. In the complex structure, DNA-PKcs, KU70, KU80 and DNA duplex form a 650-kDa heterotetramer with 1:1:1:1 stoichiometry. The N-terminal α-solenoid (∼2 800 residues) of DNA-PKcs adopts a double-ring fold and connects the catalytic core domain of DNA-PKcs and KU70/80-DNA. DNA-PKcs and KU70/80 together form a DNA-binding tunnel, which cradles ∼30-bp DNA and prevents sliding inward of DNA-PKcs along with DNA duplex, suggesting a mechanism by which the broken DNA end is protected from unnecessary processing. Structural and biochemical analyses indicate that KU70/80 and DNA coordinately induce conformational changes of DNA-PKcs and allosterically stimulate its kinase activity. We propose a model for activation of DNA-PKcs in which allosteric signals are generated upon DNA-PK holoenzyme formation and transmitted to the kinase domain through N-terminal HEAT repeats and FAT domain of DNA-PKcs. Our studies suggest a mechanism for recognition and protection of broken DNA ends and provide a structural basis for understanding the activation of DNA-PKcs and DNA-PK-mediated NHEJ pathway.
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Maag JLV, Fisher OM, Levert-Mignon A, Kaczorowski DC, Thomas ML, Hussey DJ, Watson DI, Wettstein A, Bobryshev YV, Edwards M, Dinger ME, Lord RV. Novel Aberrations Uncovered in Barrett's Esophagus and Esophageal Adenocarcinoma Using Whole Transcriptome Sequencing. Mol Cancer Res 2017; 15:1558-1569. [PMID: 28751461 DOI: 10.1158/1541-7786.mcr-17-0332] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 06/30/2017] [Accepted: 07/21/2017] [Indexed: 11/16/2022]
Abstract
Esophageal adenocarcinoma (EAC) has one of the fastest increases in incidence of any cancer, along with poor five-year survival rates. Barrett's esophagus (BE) is the main risk factor for EAC; however, the mechanisms driving EAC development remain poorly understood. Here, transcriptomic profiling was performed using RNA-sequencing (RNA-seq) on premalignant and malignant Barrett's tissues to better understand this disease. Machine-learning and network analysis methods were applied to discover novel driver genes for EAC development. Identified gene expression signatures for the distinction of EAC from BE were validated in separate datasets. An extensive analysis of the noncoding RNA (ncRNA) landscape was performed to determine the involvement of novel transcriptomic elements in Barrett's disease and EAC. Finally, transcriptomic mutational investigation of genes that are recurrently mutated in EAC was performed. Through these approaches, novel driver genes were discovered for EAC, which involved key cell cycle and DNA repair genes, such as BRCA1 and PRKDC. A novel 4-gene signature (CTSL, COL17A1, KLF4, and E2F3) was identified, externally validated, and shown to provide excellent distinction of EAC from BE. Furthermore, expression changes were observed in 685 long noncoding RNAs (lncRNA) and a systematic dysregulation of repeat elements across different stages of Barrett's disease, with wide-ranging downregulation of Alu elements in EAC. Mutational investigation revealed distinct pathways activated between EAC tissues with or without TP53 mutations compared with Barrett's disease. In summary, transcriptome sequencing revealed altered expression of numerous novel elements, processes, and networks in EAC and premalignant BE.Implications: This study identified opportunities to improve early detection and treatment of patients with BE and esophageal adenocarcinoma. Mol Cancer Res; 15(11); 1558-69. ©2017 AACR.
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Affiliation(s)
- Jesper L V Maag
- Genome Informatics, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Oliver M Fisher
- Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia.,Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia
| | - Angelique Levert-Mignon
- Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia
| | - Dominik C Kaczorowski
- Genome Informatics, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Melissa L Thomas
- Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia.,University of Notre Dame School of Medicine, Sydney, Australia
| | - Damian J Hussey
- Department of Surgery, Flinders University, Adelaide, Australia
| | - David I Watson
- Department of Surgery, Flinders University, Adelaide, Australia
| | - Antony Wettstein
- Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia
| | - Yuri V Bobryshev
- Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia.,Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia
| | - Melanie Edwards
- Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia.,University of Notre Dame School of Medicine, Sydney, Australia
| | - Marcel E Dinger
- Genome Informatics, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia. .,Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Reginald V Lord
- Gastroesophageal Cancer Program, St. Vincent's Centre for Applied Medical Research, Sydney, Australia. .,University of Notre Dame School of Medicine, Sydney, Australia
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Yin K, Chhabra Y, Tropée R, Lim YC, Fane M, Dray E, Sturm RA, Smith AG. NR4A2 Promotes DNA Double-strand Break Repair Upon Exposure to UVR. Mol Cancer Res 2017; 15:1184-1196. [PMID: 28607006 DOI: 10.1158/1541-7786.mcr-17-0002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 04/07/2017] [Accepted: 06/06/2017] [Indexed: 11/16/2022]
Abstract
Exposure of melanocytes to ultraviolet radiation (UVR) induces the formation of UV lesions that can produce deleterious effects in genomic DNA. Encounters of replication forks with unrepaired UV lesions can lead to several complex phenomena, such as the formation of DNA double-strand breaks (DSBs). The NR4A family of nuclear receptors are transcription factors that have been associated with mediating DNA repair functions downstream of the MC1R signaling pathway in melanocytes. In particular, emerging evidence shows that upon DNA damage, the NR4A2 receptor can translocate to sites of UV lesion by mechanisms requiring post-translational modifications within the N-terminal domain and at a serine residue in the DNA-binding domain at position 337. Following this, NR4A2 aids in DNA repair by facilitating chromatin relaxation, allowing accessibility for DNA repair machinery. Using A2058 and HT144 melanoma cells engineered to stably express wild-type or mutant forms of the NR4A2 proteins, we reveal that the expression of functional NR4A2 is associated with elevated cytoprotection against UVR. Conversely, knockdown of NR4A2 expression by siRNA results in a significant loss of cell viability after UV insult. By analyzing the kinetics of the ensuing 53BP1 and RAD51 foci following UV irradiation, we also reveal that the expression of mutant NR4A2 isoforms, lacking the ability to translocate, transactivate, or undergo phosphorylation, display compromised repair capacity.Implications: These data expand the understanding of the mechanism by which the NR4A2 nuclear receptor can facilitate DNA DSB repair. Mol Cancer Res; 15(9); 1184-96. ©2017 AACR.
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Affiliation(s)
- Kelvin Yin
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Yash Chhabra
- Queensland University of Technology, Translational Research Institute, Brisbane, Queensland, Australia.,Dermatology Research Centre, The University of Queensland-Diamantina Institute, Translational Research Institute, Brisbane, Queensland, Australia
| | - Romain Tropée
- Queensland University of Technology, Translational Research Institute, Brisbane, Queensland, Australia
| | - Yi Chieh Lim
- Translational Brain Cancer Research, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Mitchell Fane
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Eloise Dray
- Queensland University of Technology, Translational Research Institute, Brisbane, Queensland, Australia.,Queensland University of Technology, Institute of Health and Biomedical Innovation, Kelvin Grove, Queensland, Australia.,Mater Research - The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Richard A Sturm
- Dermatology Research Centre, The University of Queensland-Diamantina Institute, Translational Research Institute, Brisbane, Queensland, Australia
| | - Aaron G Smith
- Dermatology Research Centre, The University of Queensland-Diamantina Institute, Translational Research Institute, Brisbane, Queensland, Australia. .,Queensland University of Technology, Institute of Health and Biomedical Innovation, Kelvin Grove, Queensland, Australia
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Ihmaid S, Ahmed HE, Al-Sheikh Ali A, Sherif YE, Tarazi HM, Riyadh SM, Zayed MF, Abulkhair HS, Rateb HS. Rational design, synthesis, pharmacophore modeling, and docking studies for identification of novel potent DNA-PK inhibitors. Bioorg Chem 2017; 72:234-247. [DOI: 10.1016/j.bioorg.2017.04.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 10/19/2022]
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Sun B, Ross SM, Rowley S, Adeleye Y, Clewell RA. Contribution of ATM and ATR kinase pathways to p53-mediated response in etoposide and methyl methanesulfonate induced DNA damage. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:72-83. [PMID: 28195382 DOI: 10.1002/em.22070] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 06/06/2023]
Abstract
p53 is a key integrator of cellular response to DNA damage, supporting post-translational repair and driving transcription-mediated responses including cell cycle arrest, apoptosis, and repair. DNA damage sensing kinases recognize different types of DNA damage and initiate specific responses through various post-translational modifications of p53. This study evaluated chemical specificity of the p53 pathway response by manipulating p53 or its upstream kinases and assessing the effect on DNA damage and cellular responses to prototype chemicals: etoposide (ETP, topoisomerase II inhibitor) and methyl methane sulfonate (MMS, alkylating agent). p53-deficient cells demonstrated reduced accumulation of the p53 target proteins MDM2, p21, and Wip1; reduced apoptotic response; and increased DNA damage (p-H2AX and micronuclei) with both chemicals. However, p53 was not essential for cell cycle arrest in HT1080 or HCT116 cells. The two chemicals induced different patterns of kinase activation, particularly in terms of Chk 1, Chk 2, p38, and ERK 1/2. However, inhibition of the ATM pathway showed a greater effect on p53 activtation, apoptosis, and accumulation of DNA damage than ATR-Chk 1 or the MAP kinases regardless of the chemical used. These results indicate that ATM is the predominant upstream kinase responsible for activation of the p53-mediated DNA damage response for both MMS and ETP, though the downstream kinase response is markedly different. Environ. Mol. Mutagen. 58:72-83, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Bin Sun
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, 27709
| | - Susan M Ross
- ScitoVation, LLC, Research Triangle Park, NC, 27709
| | - Sean Rowley
- ScitoVation, LLC, Research Triangle Park, NC, 27709
| | - Yeyejide Adeleye
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, United Kingdom
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Nagasawa H, Lin YF, Kato TA, Brogan JR, Shih HY, Kurimasa A, Bedford JS, Chen BPC, Little JB. Coordination of the Ser2056 and Thr2609 Clusters of DNA-PKcs in Regulating Gamma Rays and Extremely Low Fluencies of Alpha-Particle Irradiation to G 0/G 1 Phase Cells. Radiat Res 2017; 187:259-267. [PMID: 28118114 DOI: 10.1667/rr14679.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The catalytic subunit of DNA dependent protein kinase (DNA-PKcs) and its kinase activity are critical for mediation of non-homologous end-joining (NHEJ) of DNA double-strand breaks (DSB) in mammalian cells after gamma-ray irradiation. Additionally, DNA-PKcs phosphorylations at the T2609 cluster and the S2056 cluster also affect DSB repair and cellular sensitivity to gamma radiation. Previously we reported that phosphorylations within these two regions affect not only NHEJ but also homologous recombination repair (HRR) dependent DSB repair. In this study, we further examine phenotypic effects on cells bearing various combinations of mutations within either or both regions. Effects studied included cell killing as well as chromosomal aberration induction after 0.5-8 Gy gamma-ray irradiation delivered to synchronized cells during the G0/G1 phase of the cell cycle. Blocking phosphorylation within the T2609 cluster was most critical regarding sensitization and depended on the number of available phosphorylation sites. It was also especially interesting that only one substitution of alanine in each of the two clusters separately abolished the restoration of wild-type sensitivity by DNA-PKcs. Similar patterns were seen for induction of chromosomal aberrations, reflecting their connection to cell killing. To study possible change in coordination between HRR and NHEJ directed repair in these DNA-PKcs mutant cell lines, we compared the induction of sister chromatid exchanges (SCEs) by very low fluencies of alpha particles with mutant cells defective in the HRR pathway that is required for induction of SCEs. Levels of true SCEs induced by very low fluence of alpha-particle irradiation normally seen in wild-type cells were only slightly decreased in the S2056 cluster mutants, but were completely abolished in the T2609 cluster mutants and were indistinguishable from levels seen in HRR deficient cells. Again, a single substitution in the S2056 together with a single substitution in the T2609 cluster abolished SCE formation and thus also effectively interferes with HRR.
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Affiliation(s)
- Hatsumi Nagasawa
- a Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Yu-Fen Lin
- b Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Takamitsu A Kato
- a Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - John R Brogan
- a Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Hung-Ying Shih
- b Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Akihiro Kurimasa
- c Tohoku Medical and Pharmaceutical University, Sendai, Japan, 981-8558; and
| | - Joel S Bedford
- a Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Benjamin P C Chen
- b Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - John B Little
- d Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115
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48
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Pascale RM, Joseph C, Latte G, Evert M, Feo F, Calvisi DF. DNA-PKcs: A promising therapeutic target in human hepatocellular carcinoma? DNA Repair (Amst) 2016; 47:12-20. [PMID: 27789167 DOI: 10.1016/j.dnarep.2016.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/11/2016] [Indexed: 12/27/2022]
Abstract
Hepatocellular carcinoma (HCC) is a frequent and deadly disease worldwide. The absence of effective therapies when the tumor is surgically unresectable leads to an extremely poor outcome of HCC patients. Thus, it is mandatory to elucidate the molecular pathogenesis of HCC in order to develop novel therapeutic strategies against this pernicious tumor. Mounting evidence indicates that suppression of the DNA damage response machinery might be deleterious for the survival and growth of the tumor cells. In particular, DNA dependent protein kinase catalytic subunit (DNA-PKcs), a major player in the non-homologous end-joining (NHEJ) repair process, seems to represent a valuable target for innovative anti-neoplastic therapies in cancer. DNA-PKcs levels are strongly upregulated and associated with a poor clinical outcome in various tumor types, including HCC. Importantly, DNA-PKcs not only protects tumor cells from harmful DNA insults coming either from the microenvironment or chemotherapeutic drug treatments, but also possesses additional properties, independent from its DNA repair activity, that provide growth advantages to cancer cells. These properties (metabolic and gene reprogramming, invasiveness and metastasis, resistance to apoptosis, etc.) have started to be elucidated. In the present review, we summarize the physiologic and oncogenic roles of DNA-PKcs, with a special emphasis on liver cancer. In particular, this work focuses on the molecular mechanism whereby DNA-PKcs exerts its pro-tumorigenic activity in cancer cells. In addition, the upstream regulator of DNA-PKcs activation as well as its downstream effectors thus far identified are illustrated. Furthermore, the potential therapeutic strategies aimed at inhibiting DNA-PKcs activity in HCC are discussed.
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Affiliation(s)
- Rosa M Pascale
- Department of Clinical and Experimental Medicine, University of Sassari, 07100 Sassari, Italy
| | - Christy Joseph
- Institute of Pathology, Universitätsmedizin Greifswald, 17489 Greifswald, Germany
| | - Gavinella Latte
- Department of Clinical and Experimental Medicine, University of Sassari, 07100 Sassari, Italy
| | - Matthias Evert
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
| | - Francesco Feo
- Department of Clinical and Experimental Medicine, University of Sassari, 07100 Sassari, Italy
| | - Diego F Calvisi
- Department of Clinical and Experimental Medicine, University of Sassari, 07100 Sassari, Italy; Institute of Pathology, Universitätsmedizin Greifswald, 17489 Greifswald, Germany.
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49
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Chakraborty A, Tapryal N, Venkova T, Horikoshi N, Pandita RK, Sarker AH, Sarkar PS, Pandita TK, Hazra TK. Classical non-homologous end-joining pathway utilizes nascent RNA for error-free double-strand break repair of transcribed genes. Nat Commun 2016; 7:13049. [PMID: 27703167 PMCID: PMC5059474 DOI: 10.1038/ncomms13049] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/30/2016] [Indexed: 12/30/2022] Open
Abstract
DNA double-strand breaks (DSBs) leading to loss of nucleotides in the transcribed region can be lethal. Classical non-homologous end-joining (C-NHEJ) is the dominant pathway for DSB repair (DSBR) in adult mammalian cells. Here we report that during such DSBR, mammalian C-NHEJ proteins form a multiprotein complex with RNA polymerase II and preferentially associate with the transcribed genes after DSB induction. Depletion of C-NHEJ factors significantly abrogates DSBR in transcribed but not in non-transcribed genes. We hypothesized that nascent RNA can serve as a template for restoring the missing sequences, thus allowing error-free DSBR. We indeed found pre-mRNA in the C-NHEJ complex. Finally, when a DSB-containing plasmid with several nucleotides deleted within the E. coli lacZ gene was allowed time to repair in lacZ-expressing mammalian cells, a functional lacZ plasmid could be recovered from control but not C-NHEJ factor-depleted cells, providing important mechanistic insights into C-NHEJ-mediated error-free DSBR of the transcribed genome. Most adult mammalian cells prefer to repair double-strand DNA breaks though the classical nonhomologous end-joining pathway. Here the authors present evidence that a nascent RNA transcript can serve as a template to facilitate error-free repair.
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Affiliation(s)
- Anirban Chakraborty
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nisha Tapryal
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tatiana Venkova
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nobuo Horikoshi
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Raj K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Altaf H Sarker
- Division of Life Sciences, Department of Cancer and DNA Damage Responses, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Partha S Sarkar
- Department of Neurology and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tej K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Tapas K Hazra
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
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50
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Tarazi H, Saleh E, El-Awady R. In-silico screening for DNA-dependent protein kinase (DNA-PK) inhibitors: Combined homology modeling, docking, molecular dynamic study followed by biological investigation. Biomed Pharmacother 2016; 83:693-703. [DOI: 10.1016/j.biopha.2016.07.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 07/17/2016] [Accepted: 07/19/2016] [Indexed: 10/21/2022] Open
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