1
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Chatterjee S, Starrett GJ. Microhomology-mediated repair machinery and its relationship with HPV-mediated oncogenesis. J Med Virol 2024; 96:e29674. [PMID: 38757834 DOI: 10.1002/jmv.29674] [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: 12/30/2023] [Revised: 04/19/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024]
Abstract
Human Papillomaviruses (HPV) are a diverse family of non-enveloped dsDNA viruses that infect the skin and mucosal epithelia. Persistent HPV infections can lead to cancer frequently involving integration of the virus into the host genome, leading to sustained oncogene expression and loss of capsid and genome maintenance proteins. Microhomology-mediated double-strand break repair, a DNA double-stranded breaks repair pathway present in many organisms, was initially thought to be a backup but it's now seen as vital, especially in homologous recombination-deficient contexts. Increasing evidence has identified microhomology (MH) near HPV integration junctions, suggesting MH-mediated repair pathways drive integration. In this comprehensive review, we present a detailed summary of both the mechanisms underlying MH-mediated repair and the evidence for its involvement in HPV integration in cancer. Lastly, we highlight the involvement of these processes in the integration of other DNA viruses and the broader implications on virus lifecycles and host innate immune response.
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Affiliation(s)
- Subhajit Chatterjee
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gabriel J Starrett
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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2
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Jones KM, Bryan A, McCunn E, Lantz PE, Blalock H, Ojeda IC, Mehta K, Cosper PF. The Causes and Consequences of DNA Damage and Chromosomal Instability Induced by Human Papillomavirus. Cancers (Basel) 2024; 16:1662. [PMID: 38730612 PMCID: PMC11083350 DOI: 10.3390/cancers16091662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
High-risk human papillomaviruses (HPVs) are the main cause of cervical, oropharyngeal, and anogenital cancers, which are all treated with definitive chemoradiation therapy when locally advanced. HPV proteins are known to exploit the host DNA damage response to enable viral replication and the epithelial differentiation protocol. This has far-reaching consequences for the host genome, as the DNA damage response is critical for the maintenance of genomic stability. HPV+ cells therefore have increased DNA damage, leading to widespread genomic instability, a hallmark of cancer, which can contribute to tumorigenesis. Following transformation, high-risk HPV oncoproteins induce chromosomal instability, or chromosome missegregation during mitosis, which is associated with a further increase in DNA damage, particularly due to micronuclei and double-strand break formation. Thus, HPV induces significant DNA damage and activation of the DNA damage response in multiple contexts, which likely affects radiation sensitivity and efficacy. Here, we review how HPV activates the DNA damage response, how it induces chromosome missegregation and micronuclei formation, and discuss how these factors may affect radiation response. Understanding how HPV affects the DNA damage response in the context of radiation therapy may help determine potential mechanisms to improve therapeutic response.
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Affiliation(s)
- Kathryn M. Jones
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Ava Bryan
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Emily McCunn
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Pate E. Lantz
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Hunter Blalock
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Isabel C. Ojeda
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Kavi Mehta
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53705, USA
- Carbone Cancer Center, University of Wisconsin, Madison, WI 53705, USA
| | - Pippa F. Cosper
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- Carbone Cancer Center, University of Wisconsin, Madison, WI 53705, USA
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3
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Kannan S, Gillespie SW, Picking WL, Picking WD, Lorson CL, Singh K. Inhibitors against DNA Polymerase I Family of Enzymes: Novel Targets and Opportunities. BIOLOGY 2024; 13:204. [PMID: 38666816 PMCID: PMC11048162 DOI: 10.3390/biology13040204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024]
Abstract
DNA polymerases replicate cellular genomes and/or participate in the maintenance of genome integrity. DNA polymerases sharing high sequence homology with E. coli DNA polymerase I (pol I) have been grouped in Family A. Pol I participates in Okazaki fragment maturation and in bacterial genome repair. Since its discovery in 1956, pol I has been extensively studied, primarily to gain deeper insights into the mechanism of DNA replication. As research on DNA polymerases advances, many novel functions of this group of polymerases are being uncovered. For example, human DNA polymerase θ (a Family A DNA pol) has been shown to synthesize DNA using RNA as a template, a function typically attributed to retroviral reverse transcriptase. Increased interest in drug discovery against pol θ has emerged due to its roles in cancer. Likewise, Pol I family enzymes also appear attractive as drug-development targets against microbial infections. Development of antimalarial compounds targeting apicoplast apPOL, an ortholog of Pol I, further extends the targeting of this family of enzymes. Here, we summarize reported drug-development efforts against Family A polymerases and future perspective regarding these enzymes as antibiotic targets. Recently developed techniques, such as artificial intelligence, can be used to facilitate the development of new drugs.
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Affiliation(s)
- Saathvik Kannan
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Samuel W. Gillespie
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Wendy L. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - William D. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Christian L. Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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4
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Yi G, Sung Y, Kim C, Ra JS, Hirakawa H, Kato T, Fujimori A, Kim H, Takata KI. DNA polymerase θ-mediated repair of high LET radiation-induced complex DNA double-strand breaks. Nucleic Acids Res 2023; 51:2257-2269. [PMID: 36805268 PMCID: PMC10018357 DOI: 10.1093/nar/gkad076] [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: 07/19/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
DNA polymerase θ (POLQ) is a unique DNA polymerase that is able to perform microhomology-mediated end-joining as well as translesion synthesis (TLS) across an abasic (AP) site and thymine glycol (Tg). However, the biological significance of the TLS activity is currently unknown. Herein we provide evidence that the TLS activity of POLQ plays a critical role in repairing complex DNA double-strand breaks (DSBs) induced by high linear energy transfer (LET) radiation. Radiotherapy with high LET radiation such as carbon ions leads to more deleterious biological effects than corresponding doses of low LET radiation such as X-rays. High LET-induced DSBs are considered to be complex, carrying additional DNA damage such as AP site and Tg in close proximity to the DSB sites. However, it is not clearly understood how complex DSBs are processed in mammalian cells. We demonstrated that genetic disruption of POLQ results in an increase of chromatid breaks and enhanced cellular sensitivity following treatment with high LET radiation. At the biochemical level, POLQ was able to bypass an AP site and Tg during end-joining and was able to anneal two single-stranded DNA tails when DNA lesions were located outside the microhomology. This study offers evidence that POLQ is directly involved in the repair of complex DSBs.
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Affiliation(s)
- Geunil Yi
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yubin Sung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Chanwoo Kim
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Hirokazu Hirakawa
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Takamitsu A Kato
- Department of Environmental & Radiological Health Sciences, Colorado State University, Colorado 80523, USA
| | - Akira Fujimori
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Hajin Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Kei-ichi Takata
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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5
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Multifaceted Nature of DNA Polymerase θ. Int J Mol Sci 2023; 24:ijms24043619. [PMID: 36835031 PMCID: PMC9962433 DOI: 10.3390/ijms24043619] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/26/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
DNA polymerase θ belongs to the A family of DNA polymerases and plays a key role in DNA repair and damage tolerance, including double-strand break repair and DNA translesion synthesis. Pol θ is often overexpressed in cancer cells and promotes their resistance to chemotherapeutic agents. In this review, we discuss unique biochemical properties and structural features of Pol θ, its multiple roles in protection of genome stability and the potential of Pol θ as a target for cancer treatment.
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6
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Abstract
DNA polymerase θ (Pol θ) is a DNA repair enzyme widely conserved in animals and plants. Pol θ uses short DNA sequence homologies to initiate repair of double-strand breaks by theta-mediated end joining. The DNA polymerase domain of Pol θ is at the C terminus and is connected to an N-terminal DNA helicase-like domain by a central linker. Pol θ is crucial for maintenance of damaged genomes during development, protects DNA against extensive deletions, and limits loss of heterozygosity. The cost of using Pol θ for genome protection is that a few nucleotides are usually deleted or added at the repair site. Inactivation of Pol θ often enhances the sensitivity of cells to DNA strand-breaking chemicals and radiation. Since some homologous recombination-defective cancers depend on Pol θ for growth, inhibitors of Pol θ may be useful in treating such tumors.
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Affiliation(s)
- Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA;
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA;
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7
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Baxter JS, Zatreanu D, Pettitt SJ, Lord CJ. Resistance to DNA repair inhibitors in cancer. Mol Oncol 2022; 16:3811-3827. [PMID: 35567571 PMCID: PMC9627783 DOI: 10.1002/1878-0261.13224] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/25/2022] [Accepted: 05/12/2022] [Indexed: 12/24/2022] Open
Abstract
The DNA damage response (DDR) represents a complex network of proteins which detect and repair DNA damage, thereby maintaining the integrity of the genome and preventing the transmission of mutations and rearranged chromosomes to daughter cells. Faults in the DDR are a known driver and hallmark of cancer. Furthermore, inhibition of DDR enzymes can be used to treat the disease. This is exemplified by PARP inhibitors (PARPi) used to treat cancers with defects in the homologous recombination DDR pathway. A series of novel DDR targets are now also under pre-clinical or clinical investigation, including inhibitors of ATR kinase, WRN helicase or the DNA polymerase/helicase Polθ (Pol-Theta). Drug resistance is a common phenomenon that impairs the overall effectiveness of cancer treatments and there is already some understanding of how resistance to PARPi occurs. Here, we discuss how an understanding of PARPi resistance could inform how resistance to new drugs targeting the DDR emerges. We also discuss potential strategies that could limit the impact of these therapy resistance mechanisms in cancer.
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Affiliation(s)
- Joseph S. Baxter
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Diana Zatreanu
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Stephen J. Pettitt
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Christopher J. Lord
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
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8
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DNA Polymerase Theta Plays a Critical Role in Pancreatic Cancer Development and Metastasis. Cancers (Basel) 2022; 14:cancers14174077. [PMID: 36077614 PMCID: PMC9454495 DOI: 10.3390/cancers14174077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC), due to its genomic heterogeneity and lack of effective treatment, despite decades of intensive research, will become the second leading cause of cancer-related deaths by 2030. Step-wise acquisition of mutations, due to genomic instability, is considered to drive the development of PDAC; the KRAS mutation occurs in 95 to 100% of human PDAC, and is already detectable in early premalignant lesions designated as pancreatic intraepithelial neoplasia (PanIN). This mutation is possibly the key event leading to genomic instability and PDAC development. Our study aimed to investigate the role of the error-prone DNA double-strand breaks (DSBs) repair pathway, alt-EJ, in the presence of the KRAS G12D mutation in pancreatic cancer development. Our findings show that oncogenic KRAS contributes to increasing the expression of Polθ, Lig3, and Mre11, key components of alt-EJ in both mouse and human PDAC models. We further confirm increased catalytic activity of alt-EJ in a mouse and human model of PDAC bearing the KRAS G12D mutation. Subsequently, we focused on estimating the impact of alt-EJ inactivation by polymerase theta (Polθ) deletion on pancreatic cancer development, and survival in genetically engineered mouse models (GEMMs) and cancer patients. Here, we show that even though Polθ deficiency does not fully prevent the development of pancreatic cancer, it significantly delays the onset of PanIN formation, prolongs the overall survival of experimental mice, and correlates with the overall survival of pancreatic cancer patients in the TCGA database. Our study clearly demonstrates the role of alt-EJ in the development of PDAC, and alt-EJ may be an attractive therapeutic target for pancreatic cancer patients.
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9
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Vanson S, Li Y, Wood RD, Doublié S. Probing the structure and function of polymerase θ helicase-like domain. DNA Repair (Amst) 2022; 116:103358. [PMID: 35753097 PMCID: PMC10329254 DOI: 10.1016/j.dnarep.2022.103358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
DNA Polymerase θ is the key actuator of the recently identified double-strand break repair pathway, theta-mediated end joining (TMEJ). It is the only known polymerase to have a 3-domain architecture containing an independently functional family A DNA polymerase tethered by a long central region to an N-terminal helicase-like domain (HLD). Full-length polymerase θ and the isolated HLD hydrolyze ATP in the presence of DNA, but no processive DNA duplex unwinding has been observed. Based on sequence and structure conservation, the HLD is classified as a member of helicase superfamily II and, more specifically, the Ski2-like family. The specific subdomain composition and organization most closely resemble that of archaeal DNA repair helicases Hel308 and Hjm. The underlying structural basis as to why the HLD is not able to processively unwind duplex DNA, despite its similarity to bona fide helicases, remains elusive. Activities of the HLD include ATP hydrolysis, protein displacement, and annealing of complementary DNA. These observations have led to speculation about the role of the HLD within the context of double-strand break repair via TMEJ, such as removal of single-stranded DNA binding proteins like RPA and RAD51 and microhomology alignment. This review summarizes the structural classification and organization of the polymerase θ HLD and its homologs and explores emerging data on its biochemical activities. We conclude with a simple, speculative model for the HLD's role in TMEJ.
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Affiliation(s)
- Scott Vanson
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA
| | - Yuzhen Li
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA.
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Prodhomme MK, Péricart S, Pommier RM, Morel AP, Brunac AC, Franchet C, Moyret-Lalle C, Brousset P, Puisieux A, Hoffmann JS, Tissier A. Opposite Roles for ZEB1 and TMEJ in the Regulation of Breast Cancer Genome Stability. Front Cell Dev Biol 2021; 9:727429. [PMID: 34458275 PMCID: PMC8388841 DOI: 10.3389/fcell.2021.727429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 07/23/2021] [Indexed: 12/22/2022] Open
Abstract
Breast cancer cells frequently acquire mutations in faithful DNA repair genes, as exemplified by BRCA-deficiency. Moreover, overexpression of an inaccurate DNA repair pathway may also be at the origin of the genetic instability arising during the course of cancer progression. The specific gain in expression of POLQ, encoding the error-prone DNA polymerase Theta (POLθ) involved in theta-mediated end joining (TMEJ), is associated with a characteristic mutational signature. To gain insight into the mechanistic regulation of POLQ expression, this review briefly presents recent findings on the regulation of POLQ in the claudin-low breast tumor subtype, specifically expressing transcription factors involved in epithelial-to-mesenchymal transition (EMT) such as ZEB1 and displaying a paucity in genomic abnormality.
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Affiliation(s)
- Mélanie K Prodhomme
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Sarah Péricart
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Roxane M Pommier
- Gilles Thomas Bioinformatics Platform, Centre Léon Bérard, Cancer Research Centre of Lyon, Lyon, France
| | - Anne-Pierre Morel
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Anne-Cécile Brunac
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Camille Franchet
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Caroline Moyret-Lalle
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Pierre Brousset
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Alain Puisieux
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,Institut Curie, Versailles Saint-Quentin-en-Yvelines University, PSL Research University, Paris, France
| | - Jean-Sébastien Hoffmann
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Agnès Tissier
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
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11
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Sizova I, Kelterborn S, Verbenko V, Kateriya S, Hegemann P. Chlamydomonas POLQ is necessary for CRISPR/Cas9-mediated gene targeting. G3 (BETHESDA, MD.) 2021; 11:jkab114. [PMID: 33836052 PMCID: PMC8495919 DOI: 10.1093/g3journal/jkab114] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023]
Abstract
The use of CRISPR/Cas endonucleases has revolutionized gene editing techniques for research on Chlamydomonas reinhardtii. To better utilize the CRISPR/Cas system, it is essential to develop a more comprehensive understanding of the DNA repair pathways involved in genome editing. In this study, we have analyzed contributions from canonical KU80/KU70-dependent nonhomologous end-joining (cNHEJ) and DNA polymerase theta (POLQ)-mediated end joining on SpCas9-mediated untemplated mutagenesis and homology-directed repair (HDR)/gene inactivation in Chlamydomonas. Using CRISPR/SpCas9 technology, we generated DNA repair-defective mutants ku80, ku70, polQ for gene targeting experiments. Our results show that untemplated repair of SpCas9-induced double strand breaks results in mutation spectra consistent with an involvement of both KU80/KU70 and POLQ. In addition, the inactivation of POLQ was found to negatively affect HDR of the inactivated paromomycin-resistant mut-aphVIII gene when donor single-stranded oligos were used. Nevertheless, mut-aphVIII was still repaired by homologous recombination in these mutants. POLQ inactivation suppressed random integration of transgenes co-transformed with the donor ssDNA. KU80 deficiency did not affect these events but instead was surprisingly found to stimulate HDR/gene inactivation. Our data suggest that in Chlamydomonas, POLQ is the main contributor to CRISPR/Cas-induced HDR and random integration of transgenes, whereas KU80/KU70 potentially plays a secondary role. We expect our results will lead to improvement of genome editing in C. reinhardtii and can be used for future development of algal biotechnology.
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Affiliation(s)
- Irina Sizova
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Simon Kelterborn
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
| | - Valeriy Verbenko
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Suneel Kateriya
- Laboratory of Optobiology School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Peter Hegemann
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
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12
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Depletion of DNA Polymerase Theta Inhibits Tumor Growth and Promotes Genome Instability through the cGAS-STING-ISG Pathway in Esophageal Squamous Cell Carcinoma. Cancers (Basel) 2021; 13:cancers13133204. [PMID: 34206946 PMCID: PMC8268317 DOI: 10.3390/cancers13133204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/13/2021] [Accepted: 06/23/2021] [Indexed: 12/30/2022] Open
Abstract
Simple Summary DNA polymerase theta, encoded by the human POLQ gene, is upregulated in several cancers and is associated with poor clinical outcomes. The importance of POLQ, however, has yet to be elucidated in esophageal cancer. In this study, we explored the functional impacts of POLQ and looked into its underlying mechanisms. POLQ was overexpressed in esophageal squamous cell carcinoma (ESCC) tumors associated with unfavorable prognosis and contributed to malignant phenotypes by promoting genome stability, suggesting that targeting polymerase theta may provide a potential therapeutic approach for improving ESCC management. Abstract Overexpression of the specialized DNA polymerase theta (POLQ) is frequent in breast, colon and lung cancers and has been correlated with unfavorable clinical outcomes. Here, we aimed to determine the importance and functional role of POLQ in esophageal squamous cell carcinoma (ESCC). Integrated analysis of four RNA-seq datasets showed POLQ was predominantly upregulated in ESCC tumors. High expression of POLQ was also observed in a cohort of 25 Hong Kong ESCC patients and negatively correlated with ESCC patient survival. POLQ knockout (KO) ESCC cells were sensitized to multiple genotoxic agents. Both rH2AX foci staining and the comet assay indicated a higher level of genomic instability in POLQ-depleted cells. Double KO of POLQ and FANCD2, known to promote POLQ recruitment at sites of damage, significantly impaired cell proliferation both in vitro and in vivo, as compared to either single POLQ or FANCD2 KOs. A significantly increased number of micronuclei was observed in POLQ and/or FANCD2 KO ESCC cells. Loss of POLQ and/or FANCD2 also resulted in the activation of cGAS and upregulation of interferon-stimulated genes (ISGs). Our results suggest that high abundance of POLQ in ESCC contributes to the malignant phenotype through genome instability and activation of the cGAS pathway.
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13
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Zatreanu D, Robinson HMR, Alkhatib O, Boursier M, Finch H, Geo L, Grande D, Grinkevich V, Heald RA, Langdon S, Majithiya J, McWhirter C, Martin NMB, Moore S, Neves J, Rajendra E, Ranzani M, Schaedler T, Stockley M, Wiggins K, Brough R, Sridhar S, Gulati A, Shao N, Badder LM, Novo D, Knight EG, Marlow R, Haider S, Callen E, Hewitt G, Schimmel J, Prevo R, Alli C, Ferdinand A, Bell C, Blencowe P, Bot C, Calder M, Charles M, Curry J, Ekwuru T, Ewings K, Krajewski W, MacDonald E, McCarron H, Pang L, Pedder C, Rigoreau L, Swarbrick M, Wheatley E, Willis S, Wong AC, Nussenzweig A, Tijsterman M, Tutt A, Boulton SJ, Higgins GS, Pettitt SJ, Smith GCM, Lord CJ. Polθ inhibitors elicit BRCA-gene synthetic lethality and target PARP inhibitor resistance. Nat Commun 2021; 12:3636. [PMID: 34140467 PMCID: PMC8211653 DOI: 10.1038/s41467-021-23463-8] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/30/2021] [Indexed: 02/05/2023] Open
Abstract
To identify approaches to target DNA repair vulnerabilities in cancer, we discovered nanomolar potent, selective, low molecular weight (MW), allosteric inhibitors of the polymerase function of DNA polymerase Polθ, including ART558. ART558 inhibits the major Polθ-mediated DNA repair process, Theta-Mediated End Joining, without targeting Non-Homologous End Joining. In addition, ART558 elicits DNA damage and synthetic lethality in BRCA1- or BRCA2-mutant tumour cells and enhances the effects of a PARP inhibitor. Genetic perturbation screening revealed that defects in the 53BP1/Shieldin complex, which cause PARP inhibitor resistance, result in in vitro and in vivo sensitivity to small molecule Polθ polymerase inhibitors. Mechanistically, ART558 increases biomarkers of single-stranded DNA and synthetic lethality in 53BP1-defective cells whilst the inhibition of DNA nucleases that promote end-resection reversed these effects, implicating these in the synthetic lethal mechanism-of-action. Taken together, these observations describe a drug class that elicits BRCA-gene synthetic lethality and PARP inhibitor synergy, as well as targeting a biomarker-defined mechanism of PARPi-resistance.
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Affiliation(s)
- Diana Zatreanu
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Helen M R Robinson
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Omar Alkhatib
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Marie Boursier
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Harry Finch
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Lerin Geo
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Diego Grande
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Vera Grinkevich
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Robert A Heald
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Sophie Langdon
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Jayesh Majithiya
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Claire McWhirter
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Niall M B Martin
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Shaun Moore
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Joana Neves
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Eeson Rajendra
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Marco Ranzani
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Theresia Schaedler
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Martin Stockley
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Kimberley Wiggins
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Rachel Brough
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Sandhya Sridhar
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Aditi Gulati
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Nan Shao
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Luned M Badder
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Daniela Novo
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Eleanor G Knight
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Rebecca Marlow
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Syed Haider
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | | | - Joost Schimmel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Remko Prevo
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, UK
| | - Christina Alli
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Amanda Ferdinand
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Cameron Bell
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Peter Blencowe
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Chris Bot
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Mathew Calder
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Mark Charles
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Jayne Curry
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Tennyson Ekwuru
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Katherine Ewings
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Wojciech Krajewski
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ellen MacDonald
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Hollie McCarron
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Leon Pang
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Chris Pedder
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Laurent Rigoreau
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Martin Swarbrick
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ed Wheatley
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Simon Willis
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ai Ching Wong
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Andre Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew Tutt
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Simon J Boulton
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
- The Francis Crick Institute, London, UK
| | - Geoff S Higgins
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, UK
| | - Stephen J Pettitt
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
| | - Graeme C M Smith
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK.
| | - Christopher J Lord
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
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14
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Zhou J, Gelot C, Pantelidou C, Li A, Yücel H, Davis RE, Farkkila A, Kochupurakkal B, Syed A, Shapiro GI, Tainer JA, Blagg BSJ, Ceccaldi R, D’Andrea AD. A first-in-class Polymerase Theta Inhibitor selectively targets Homologous-Recombination-Deficient Tumors. NATURE CANCER 2021; 2:598-610. [PMID: 34179826 PMCID: PMC8224818 DOI: 10.1038/s43018-021-00203-x] [Citation(s) in RCA: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DNA polymerase theta (POLθ) is synthetic lethal with Homologous Recombination (HR) deficiency and thus a candidate target for HR-deficient cancers. Through high-throughput small molecule screens we identified the antibiotic Novobiocin (NVB) as a specific POLθ inhibitor that selectively kills HR-deficient tumor cells in vitro and in vivo. NVB directly binds to the POLθ ATPase domain, inhibits its ATPase activity, and phenocopies POLθ depletion. NVB kills HR-deficient breast and ovarian tumors in GEMM, xenograft and PDX models. Increased POLθ levels predict NVB sensitivity, and BRCA-deficient tumor cells with acquired resistance to PARP inhibitors (PARPi) are sensitive to NVB in vitro and in vivo. Mechanistically, NVB-mediated cell death in PARPi-resistant cells arises from increased double-strand break end resection, leading to accumulation of single-strand DNA intermediates and non-functional RAD51 foci. Our results demonstrate that NVB may be useful alone or in combination with PARPi in treating HR-deficient tumors, including those with acquired PARPi resistance. (151/150).
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Affiliation(s)
- Jia Zhou
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Camille Gelot
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France
| | - Constantia Pantelidou
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Adam Li
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Hatice Yücel
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France
| | - Rachel E. Davis
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Anniina Farkkila
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Bose Kochupurakkal
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Aleem Syed
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Geoffrey I. Shapiro
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.,Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA, USA
| | - John A. Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Brian S. J. Blagg
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Raphael Ceccaldi
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France.,Corresponding authors: Alan D. D’Andrea, M.D., Director, Susan F. Smith Center for Women’s Cancers (SFSCWC), Director, Center for DNA Damage and Repair, Dana-Farber Cancer Institute, The Fuller-American Cancer Society Professor, Harvard Medical School, Phone: 617-632-2080, , Raphael Ceccaldi, Institut Curie, 75005, Paris, France, Phone: +33 (0)1 56 24 69 49,
| | - Alan D. D’Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.,Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA, USA.,Susan F. Smith Center for Women’s Cancers, Dana-Farber Cancer Institute, Boston, MA, USA.,Corresponding authors: Alan D. D’Andrea, M.D., Director, Susan F. Smith Center for Women’s Cancers (SFSCWC), Director, Center for DNA Damage and Repair, Dana-Farber Cancer Institute, The Fuller-American Cancer Society Professor, Harvard Medical School, Phone: 617-632-2080, , Raphael Ceccaldi, Institut Curie, 75005, Paris, France, Phone: +33 (0)1 56 24 69 49,
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15
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Zahn KE, Jensen RB, Wood RD, Doublié S. WITHDRAWN: Human DNA polymerase θ harbors DNA end-trimming activity critical for DNA repair. Mol Cell 2021; 81:1534-1547.e4. [PMID: 33577776 PMCID: PMC8231307 DOI: 10.1016/j.molcel.2021.01.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/24/2020] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
Cancers with hereditary defects in homologous recombination rely on DNA polymerase θ (pol θ) for repair of DNA double-strand breaks. During end joining, pol θ aligns microhomology tracts internal to 5'-resected broken ends. An unidentified nuclease trims the 3' ends before synthesis can occur. Here we report that a nuclease activity, which differs from the proofreading activity often associated with DNA polymerases, is intrinsic to the polymerase domain of pol θ. Like the DNA synthesis activity, the nuclease activity requires conserved metal-binding residues, metal ions, and dNTPs and is inhibited by ddNTPs or chain-terminated DNA. Our data indicate that pol θ repurposes metal ions in the polymerase active site for endonucleolytic cleavage and that the polymerase-active and end-trimming conformations of the enzyme are distinct. We reveal a nimble strategy of substrate processing that allows pol θ to trim or extend DNA depending on the DNA repair context.
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA; Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 78957, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA.
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16
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Patel PS, Algouneh A, Hakem R. Exploiting synthetic lethality to target BRCA1/2-deficient tumors: where we stand. Oncogene 2021; 40:3001-3014. [PMID: 33716297 DOI: 10.1038/s41388-021-01744-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/21/2021] [Accepted: 02/26/2021] [Indexed: 12/11/2022]
Abstract
The principle of synthetic lethality, which refers to the loss of viability resulting from the disruption of two genes, which, individually, do not cause lethality, has become an attractive target approach due to the development and clinical success of Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). In this review, we present the most recent findings on the use of PARPi in the clinic, which are currently approved for second-line therapy for advanced ovarian and breast cancer associated with mutations of BRCA1 or BRCA2 (BRCA1/2) genes. PARPi efficacy, however, appears to be limited by acquired and inherent resistance, highlighting the need for alternative and synergistic targets to eliminate these tumors. Here, we explore other identified synthetic lethal interactors of BRCA1/2, including DNA polymerase theta (POLQ), Fanconi anemia complementation group D2 (FANDC2), radiation sensitive 52 (RAD52), Flap structure-specific endonuclease 1 (FEN1), and apurinic/apyrimidinic endodeoxyribonuclease 2 (APE2), as well as other protein and nonprotein targets, for BRCA1/2-mutated cancers and their implications for future therapies. A wealth of information now exists for phenotypic and functional characterization of these novel synthetic lethal interactors of BRCA1/2, and leveraging these findings can pave the way for the development of new targeted therapies for patients suffering from these cancers.
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Affiliation(s)
- Parasvi S Patel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Arash Algouneh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Razq Hakem
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada. .,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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17
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Schrempf A, Slyskova J, Loizou JI. Targeting the DNA Repair Enzyme Polymerase θ in Cancer Therapy. Trends Cancer 2021; 7:98-111. [PMID: 33109489 DOI: 10.1016/j.trecan.2020.09.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/21/2022]
Abstract
Targeted cancer therapies represent a milestone towards personalized treatment as they function via inhibition of cancer-specific alterations. Polymerase θ (POLQ), an error-prone translesion polymerase, also involved in DNA double-strand break (DSB) repair, is often upregulated in cancer. POLQ is synthetic lethal with various DNA repair genes, including known cancer drivers such as BRCA1/2, making it essential in homologous recombination-deficient cancers. Thus, POLQ represents a promising target in cancer therapy and efforts for the development of POLQ inhibitors are actively underway with first clinical trials due to start in 2021. This review summarizes the journey of POLQ from a backup DNA repair enzyme to a promising therapeutic target for cancer treatment.
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Affiliation(s)
- Anna Schrempf
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
| | - Jana Slyskova
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria.
| | - Joanna I Loizou
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria.
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18
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Pan YR, Wu CE, Yeh CN. ATM Inhibitor Suppresses Gemcitabine-Resistant BTC Growth in a Polymerase θ Deficiency-Dependent Manner. Biomolecules 2020; 10:E1529. [PMID: 33182492 PMCID: PMC7697425 DOI: 10.3390/biom10111529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 12/19/2022] Open
Abstract
Patients with advanced biliary tract cancer (BTC) inevitably experience progression after first-line, gemcitabine-based chemotherapy, due to chemo-resistance. The genetic alterations of DNA damage repair (DDR) genes are usually determined in BTC tumors. In this study, we found that the POLQ mRNA levels are downregulated and the ataxia-telangiectasia mutated (ATM) inhibitor AZD0156 was more sensitive in gemcitabine-resistant BTC sublines than in the parental cell lines. The knockdown of DNA polymerase θ does not affect cell proliferation, but its combination with the ATM inhibitor facilitated cell death in gemcitabine-resistant and gemcitabine-intensive BTC cells. Moreover, in the DNA damage caused by photon, hydrogen peroxide, or chemotherapy drugs, synthetic lethal interactions were found in combination with ATM inhibition by AZD0156 and DNA polymerase θ depletion, resulting in increased DNA damage accumulation and micronucleus formation, as well as reduced cell survival and colony formation. Collectively, our results reveal that ATM acts as a potential target in gemcitabine-resistant and DNA polymerase θ-deficient BTC.
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Affiliation(s)
- Yi-Ru Pan
- Department of General Surgery and Liver Research Center, Chang Gung Memorial Hospital, Linkou branch, Chang Gung University, Taoyuan 333, Taiwan;
| | - Chiao-En Wu
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, Chang Gung University College of Medicine, Taoyuan 333, Taiwan;
| | - Chun-Nan Yeh
- Department of General Surgery and Liver Research Center, Chang Gung Memorial Hospital, Linkou branch, Chang Gung University, Taoyuan 333, Taiwan;
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19
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Patterson-Fortin J, D'Andrea AD. Exploiting the Microhomology-Mediated End-Joining Pathway in Cancer Therapy. Cancer Res 2020; 80:4593-4600. [PMID: 32651257 PMCID: PMC7641946 DOI: 10.1158/0008-5472.can-20-1672] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/13/2020] [Accepted: 07/07/2020] [Indexed: 01/16/2023]
Abstract
Repair of DNA double-strand breaks (DSB) is performed by two major pathways, homology-dependent repair and classical nonhomologous end-joining. Recent studies have identified a third pathway, microhomology-mediated end-joining (MMEJ). MMEJ has similarities to homology-dependent repair, in that repair is initiated with end resection, leading to single-stranded 3' ends, which require microhomology upstream and downstream of the DSB. Importantly, the MMEJ pathway is commonly upregulated in cancers, especially in homologous recombination-deficient cancers, which display a distinctive mutational signature. Here, we review the molecular process of MMEJ as well as new targets and approaches exploiting the MMEJ pathway in cancer therapy.
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Affiliation(s)
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, Massachusetts
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20
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Kim DV, Makarova AV, Miftakhova RR, Zharkov DO. Base Excision DNA Repair Deficient Cells: From Disease Models to Genotoxicity Sensors. Curr Pharm Des 2020; 25:298-312. [PMID: 31198112 DOI: 10.2174/1381612825666190319112930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/13/2019] [Indexed: 12/29/2022]
Abstract
Base excision DNA repair (BER) is a vitally important pathway that protects the cell genome from many kinds of DNA damage, including oxidation, deamination, and hydrolysis. It involves several tightly coordinated steps, starting from damaged base excision and followed by nicking one DNA strand, incorporating an undamaged nucleotide, and DNA ligation. Deficiencies in BER are often embryonic lethal or cause morbid diseases such as cancer, neurodegeneration, or severe immune pathologies. Starting from the early 1980s, when the first mammalian cell lines lacking BER were produced by spontaneous mutagenesis, such lines have become a treasure trove of valuable information about the mechanisms of BER, often revealing unexpected connections with other cellular processes, such as antibody maturation or epigenetic demethylation. In addition, these cell lines have found an increasing use in genotoxicity testing, where they provide increased sensitivity and representativity to cell-based assay panels. In this review, we outline current knowledge about BER-deficient cell lines and their use.
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Affiliation(s)
- Daria V Kim
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russian Federation
| | - Alena V Makarova
- RAS Institute of Molecular Genetics, 2 Kurchatova Sq., Moscow 123182, Russian Federation
| | - Regina R Miftakhova
- Kazan Federal University, 18 Kremlevsakaya St., Kazan 420008, Russian Federation
| | - Dmitry O Zharkov
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russian Federation.,SB RAS Institute of Chemical Biology and Fu ndamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russian Federation
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21
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Brambati A, Barry RM, Sfeir A. DNA polymerase theta (Polθ) - an error-prone polymerase necessary for genome stability. Curr Opin Genet Dev 2020; 60:119-126. [PMID: 32302896 PMCID: PMC7230004 DOI: 10.1016/j.gde.2020.02.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/21/2022]
Abstract
Mammalian cells have evolved multiple pathways to repair DNA double strand breaks (DSBs) and ensure genome stability. In addition to non-homologous end-joining (NHEJ) and homologous recombination (HR), cells evolved an error-prone repair pathway termed microhomology-mediated end joining (MMEJ). The mutagenic outcome of MMEJ derives from the activity of DNA polymerase theta (Polθ) - a multidomain enzyme that is minimally expressed in normal tissue but overexpressed in tumors. Polθ expression is particularly crucial for the proliferation of HR deficient cancer cells. As a result, this mutagenic repair emerged as an attractive target for cancer therapy, and inhibitors are currently in pre-clinical development. Here, we review the multifunctionality of this enigmatic polymerase, focusing on its role during DSB repair in mammalian cells and its impact on cancer genomes.
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Affiliation(s)
- Alessandra Brambati
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Raymond Mario Barry
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Agnel Sfeir
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
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22
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Hoitsma NM, Whitaker AM, Schaich MA, Smith MR, Fairlamb MS, Freudenthal BD. Structure and function relationships in mammalian DNA polymerases. Cell Mol Life Sci 2020; 77:35-59. [PMID: 31722068 PMCID: PMC7050493 DOI: 10.1007/s00018-019-03368-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 12/19/2022]
Abstract
DNA polymerases are vital for the synthesis of new DNA strands. Since the discovery of DNA polymerase I in Escherichia coli, a diverse library of mammalian DNA polymerases involved in DNA replication, DNA repair, antibody generation, and cell checkpoint signaling has emerged. While the unique functions of these DNA polymerases are differentiated by their association with accessory factors and/or the presence of distinctive catalytic domains, atomic resolution structures of DNA polymerases in complex with their DNA substrates have revealed mechanistic subtleties that contribute to their specialization. In this review, the structure and function of all 15 mammalian DNA polymerases from families B, Y, X, and A will be reviewed and discussed with special emphasis on the insights gleaned from recently published atomic resolution structures.
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Affiliation(s)
- Nicole M Hoitsma
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Matthew A Schaich
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Mallory R Smith
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Max S Fairlamb
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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23
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Abstract
Squamous cell carcinomas (SCCs) arising from aerodigestive or anogenital epithelium that are associated with the human papillomavirus (HPV) are far more readily cured with radiation therapy than HPV-negative SCCs. The mechanism behind this increased radiosensitivity has been proposed to be secondary to defects in DNA repair, although the specific repair pathways that are disrupted have not been elucidated. To gain insight into this important biomarker of radiosensitivity, we first examined genomic patterns reflective of defects in DNA double-strand break repair, comparing HPV-associated and HPV-negative head and neck cancers (HNSCC). Compared to HPV-negative HNSCC genomes, HPV+ cases demonstrated a marked increase in the proportion of deletions with flanking microhomology, a signature associated with a backup, error-prone double-strand break repair pathway known as microhomology-mediated end-joining (MMEJ). Then, using 3 different methodologies to comprehensively profile double-strand break repair pathways in isogenic paired cell lines, we demonstrate that the HPV16 E7 oncoprotein suppresses canonical nonhomologous end-joining (NHEJ) and promotes error-prone MMEJ, providing a mechanistic rationale for the clinical radiosensitivity of these cancers.
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24
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Mara K, Charlot F, Guyon-Debast A, Schaefer DG, Collonnier C, Grelon M, Nogué F. POLQ plays a key role in the repair of CRISPR/Cas9-induced double-stranded breaks in the moss Physcomitrella patens. THE NEW PHYTOLOGIST 2019; 222:1380-1391. [PMID: 30636294 DOI: 10.1111/nph.15680] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/05/2019] [Indexed: 05/19/2023]
Abstract
Double-stranded breaks can be repaired by different mechanisms such as homologous recombination (HR), classical nonhomologous end joining (C-NHEJ) and alternative end joining (Alt-EJ). Polymerase Q (POLQ) has been proposed to be the main factor involved in Alt-EJ-mediated DNA repair. Here we describe the role of POLQ in DNA repair and gene targeting in Physcomitrella patens. The disruption of the POLQ gene does not influence the genetic stability of P. patens nor its development. The polq mutant shows the same sensitivity as wild-type towards most of the genotoxic agents tested (ultraviolet (UV), methyl methanesulfonate (MMS) and cisplatin) with the notable exception of bleomycin for which it shows less sensitivity than the wild-type. Furthermore, we show that POLQ is involved in the repair of CRISPR-Cas9-induced double-stranded breaks in P. patens. We also demonstrate that POLQ is a potential competitor and/or inhibitor of the HR repair pathway. This finding has a consequence in terms of genetic engineering, as in the absence of POLQ the frequency of gene targeting is significantly increased and the number of clean two-sided HR-mediated insertions is enhanced. Therefore, the control of POLQ activity in plants could be a useful strategy to optimize the tools of genome engineering for plant breeding.
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Affiliation(s)
- Kostlend Mara
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
| | - Florence Charlot
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
| | - Anouchka Guyon-Debast
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
| | - Didier G Schaefer
- Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland
| | - Cécile Collonnier
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
| | - Mathilde Grelon
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
| | - Fabien Nogué
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, 78000, France
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25
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Wang Z, Song Y, Li S, Kurian S, Xiang R, Chiba T, Wu X. DNA polymerase θ (POLQ) is important for repair of DNA double-strand breaks caused by fork collapse. J Biol Chem 2019; 294:3909-3919. [PMID: 30655289 PMCID: PMC6422074 DOI: 10.1074/jbc.ra118.005188] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/05/2019] [Indexed: 12/31/2022] Open
Abstract
DNA polymerase θ (POLQ) plays an important role in alternative nonhomologous end joining or microhomology-mediated end joining (alt-NHEJ/MMEJ). Here, we show that POLQ is not only required for MMEJ to repair DNA double-strand breaks (DSBs) generated by endonucleases such as I-SceI or Cas9, but is also needed for repair of DSBs derived from DNA nicks generated by Cas9 nickase. Consistently, we found that POLQ deficiency leads to sensitivity to topoisomerase inhibitors that cause DNA single-strand break (SSB) accumulation at replication forks and to ATR inhibitors that induce replication fork collapse. These studies support the function of POLQ in coping with replication stress and repairing DSBs upon fork collapse. POLQ overexpression is present in many cancer types and is associated with poor prognosis, including breast cancer regardless of BRCA1 status. We provide proof-of-concept evidence to support a novel cancer treatment strategy that combines POLQ inhibition with administration of topoisomerase or ATR inhibitors, which induces replication stress and fork collapse. Given the prevalence of POLQ overexpression in tumors, such strategy may have a significant impact on developing targeted cancer treatment.
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Affiliation(s)
- Zi Wang
- From the Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
- the Biomedical Gerontology Laboratory, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan
| | - Yadong Song
- From the Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
- the School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, China, and
| | - Shibo Li
- From the Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - Sunil Kurian
- the Division of Organ Transplant, Scripps Health, La Jolla, California 92037
| | - Rong Xiang
- the School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, China, and
| | - Takuya Chiba
- the Biomedical Gerontology Laboratory, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan
| | - Xiaohua Wu
- From the Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037,
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26
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Laverty DJ, Mortimer IP, Greenberg MM. Mechanistic Insight through Irreversible Inhibition: DNA Polymerase θ Uses a Common Active Site for Polymerase and Lyase Activities. J Am Chem Soc 2018; 140:9034-9037. [PMID: 29998737 PMCID: PMC6085753 DOI: 10.1021/jacs.8b04158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
DNA polymerase θ (Pol θ) is a multifunctional enzyme. It is nonessential in normal cells, but its upregulation in cancer cells correlates with cellular resistance to oxidative damage and poor prognosis. Pol θ possesses polymerase activity and poorly characterized lyase activity. We examined the Pol θ lyase activity on various abasic sites and determined that the enzyme is inactivated upon attempted removal of the oxidized abasic site commonly associated with C4'-oxidation (pC4-AP). Covalent modification of Pol θ by the DNA lesion enabled determination of the primary nucleophile (Lys2383) responsible for Schiff base formation in the lyase reaction. Unlike some other base excision repair polymerases, Pol θ uses a single active site for polymerase and lyase activity. Mutation of Lys2383 significantly reduces both enzyme activities but not DNA binding. Demonstration that Lys2383 is required for polymerase and lyase activities indicates that this residue is an Achilles heel for Pol θ and suggests a path forward for designing inhibitors of this attractive anticancer target.
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Affiliation(s)
- Daniel J. Laverty
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
| | - Ifor P. Mortimer
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
| | - Marc M. Greenberg
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
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27
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Quinet A, Lerner LK, Martins DJ, Menck CFM. Filling gaps in translesion DNA synthesis in human cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:127-142. [PMID: 30442338 DOI: 10.1016/j.mrgentox.2018.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 02/21/2018] [Indexed: 01/06/2023]
Abstract
During DNA replication, forks may encounter unrepaired lesions that hamper DNA synthesis. Cells have universal strategies to promote damage bypass allowing cells to survive. DNA damage tolerance can be performed upon template switch or by specialized DNA polymerases, known as translesion (TLS) polymerases. Human cells count on more than eleven TLS polymerases and this work reviews the functions of some of these enzymes: Rev1, Pol η, Pol ι, Pol κ, Pol θ and Pol ζ. The mechanisms of damage bypass vary according to the lesion, as well as to the TLS polymerases available, and may occur directly at the fork during replication. Alternatively, the lesion may be skipped, leaving a single-stranded DNA gap that will be replicated later. Details of the participation of these enzymes are revised for the replication of damaged template. TLS polymerases also have functions in other cellular processes. These include involvement in somatic hypermutation in immunoglobulin genes, direct participation in recombination and repair processes, and contributing to replicating noncanonical DNA structures. The importance of DNA damage replication to cell survival is supported by recent discoveries that certain genes encoding TLS polymerases are induced in response to DNA damaging agents, protecting cells from a subsequent challenge to DNA replication. We retrace the findings on these genotoxic (adaptive) responses of human cells and show the common aspects with the SOS responses in bacteria. Paradoxically, although TLS of DNA damage is normally an error prone mechanism, in general it protects from carcinogenesis, as evidenced by increased tumorigenesis in xeroderma pigmentosum variant patients, who are deficient in Pol η. As these TLS polymerases also promote cell survival, they constitute an important mechanism by which cancer cells acquire resistance to genotoxic chemotherapy. Therefore, the TLS polymerases are new potential targets for improving therapy against tumors.
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Affiliation(s)
- Annabel Quinet
- Saint Louis University School of Medicine, St. Louis, MO, United States.
| | - Leticia K Lerner
- MRC Laboratory of Molecular Biology,Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Davi J Martins
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Carlos F M Menck
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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28
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Family A and B DNA Polymerases in Cancer: Opportunities for Therapeutic Interventions. BIOLOGY 2018; 7:biology7010005. [PMID: 29301327 PMCID: PMC5872031 DOI: 10.3390/biology7010005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/14/2017] [Accepted: 12/29/2017] [Indexed: 02/07/2023]
Abstract
DNA polymerases are essential for genome replication, DNA repair and translesion DNA synthesis (TLS). Broadly, these enzymes belong to two groups: replicative and non-replicative DNA polymerases. A considerable body of data suggests that both groups of DNA polymerases are associated with cancer. Many mutations in cancer cells are either the result of error-prone DNA synthesis by non-replicative polymerases, or the inability of replicative DNA polymerases to proofread mismatched nucleotides due to mutations in 3'-5' exonuclease activity. Moreover, non-replicative, TLS-capable DNA polymerases can negatively impact cancer treatment by synthesizing DNA past lesions generated from treatments such as cisplatin, oxaliplatin, etoposide, bleomycin, and radiotherapy. Hence, the inhibition of DNA polymerases in tumor cells has the potential to enhance treatment outcomes. Here, we review the association of DNA polymerases in cancer from the A and B families, which participate in lesion bypass, and conduct gene replication. We also discuss possible therapeutic interventions that could be used to maneuver the role of these enzymes in tumorigenesis.
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29
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Bournique E, Dall'Osto M, Hoffmann JS, Bergoglio V. Role of specialized DNA polymerases in the limitation of replicative stress and DNA damage transmission. Mutat Res 2017; 808:62-73. [PMID: 28843435 DOI: 10.1016/j.mrfmmm.2017.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 01/31/2023]
Abstract
Replication stress is a strong and early driving force for genomic instability and tumor development. Beside replicative DNA polymerases, an emerging group of specialized DNA polymerases is involved in the technical assistance of the replication machinery in order to prevent replicative stress and its deleterious consequences. During S-phase, altered progression of the replication fork by endogenous or exogenous impediments induces replicative stress, causing cells to reach mitosis with genomic regions not fully duplicated. Recently, specific mechanisms to resolve replication intermediates during mitosis with the aim of limiting DNA damage transmission to daughter cells have been identified. In this review, we detail the two major actions of specialized DNA polymerases that limit DNA damage transmission: the prevention of replicative stress by non-B DNA replication and the recovery of stalled replication forks.
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Affiliation(s)
- Elodie Bournique
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Marina Dall'Osto
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Jean-Sébastien Hoffmann
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Valérie Bergoglio
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France.
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30
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Laverty DJ, Averill AM, Doublié S, Greenberg MM. The A-Rule and Deletion Formation During Abasic and Oxidized Abasic Site Bypass by DNA Polymerase θ. ACS Chem Biol 2017; 12:1584-1592. [PMID: 28459528 DOI: 10.1021/acschembio.7b00211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
DNA polymerase θ (Pol θ) is implicated in various cellular processes including double-strand break repair and apurinic/apyrimidinic site bypass. Because Pol θ expression correlates with poor cancer prognosis, the ability of Pol θ to bypass the C4'-oxidized abasic site (C4-AP) and 2-deoxyribonolactone (L), which are generated by cytotoxic agents, is of interest. Translesion synthesis and subsequent extension by Pol θ past C4-AP or L and an abasic site (AP) or its tetrahydrofuran analogue (F) was examined. Pol θ conducts translesion synthesis on templates containing AP and F with similar efficiencies and follows the "A-rule," inserting nucleotides in the order A > G > T. Translesion synthesis on templates containing C4-AP and L is less efficient than AP and F, and the preference for A insertion is reduced for L and absent for C4-AP. Extension past all abasic lesions (AP, F, C4-AP, and L) was significantly less efficient than translesion synthesis and yielded deletions caused by the base one or two nucleotides downstream from the lesion being used as a template, with the latter being favored. These results suggest that bypass of abasic lesions by Pol θ is highly mutagenic.
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Affiliation(s)
- Daniel J. Laverty
- Department
of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - April M. Averill
- Department
of Microbiology and Molecular Genetics, The Markey Center for Molecular
Genetics, The University of Vermont, 95 Carrigan Drive, Burlington, Vermont 05405, United States
| | - Sylvie Doublié
- Department
of Microbiology and Molecular Genetics, The Markey Center for Molecular
Genetics, The University of Vermont, 95 Carrigan Drive, Burlington, Vermont 05405, United States
| | - Marc M. Greenberg
- Department
of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
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31
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Analysis of DNA polymerase ν function in meiotic recombination, immunoglobulin class-switching, and DNA damage tolerance. PLoS Genet 2017; 13:e1006818. [PMID: 28570559 PMCID: PMC5472330 DOI: 10.1371/journal.pgen.1006818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/15/2017] [Accepted: 05/13/2017] [Indexed: 11/20/2022] Open
Abstract
DNA polymerase ν (pol ν), encoded by the POLN gene, is an A-family DNA polymerase in vertebrates and some other animal lineages. Here we report an in-depth analysis of pol ν–defective mice and human cells. POLN is very weakly expressed in most tissues, with the highest relative expression in testis. We constructed multiple mouse models for Poln disruption and detected no anatomic abnormalities, alterations in lifespan, or changed causes of mortality. Mice with inactive Poln are fertile and have normal testis morphology. However, pol ν–disrupted mice have a modestly reduced crossover frequency at a meiotic recombination hot spot harboring insertion/deletion polymorphisms. These polymorphisms are suggested to generate a looped-out primer and a hairpin structure during recombination, substrates on which pol ν can operate. Pol ν-defective mice had no alteration in DNA end-joining during immunoglobulin class-switching, in contrast to animals defective in the related DNA polymerase θ (pol θ). We examined the response to DNA crosslinking agents, as purified pol ν has some ability to bypass major groove peptide adducts and residues of DNA crosslink repair. Inactivation of Poln in mouse embryonic fibroblasts did not alter cellular sensitivity to mitomycin C, cisplatin, or aldehydes. Depletion of POLN from human cells with shRNA or siRNA did not change cellular sensitivity to mitomycin C or alter the frequency of mitomycin C-induced radial chromosomes. Our results suggest a function of pol ν in meiotic homologous recombination in processing specific substrates. The restricted and more recent evolutionary appearance of pol ν (in comparison to pol θ) supports such a specialized role. The work described here fills a current gap in the study of the 16 known DNA polymerases in vertebrate genomes. Until now, experiments with genetically disrupted mice have been reported for all but pol ν, encoded by the POLN gene. To intensively analyze the role of mammalian pol ν we generated multiple Poln-deficient murine models. We discovered that Poln is uniquely upregulated during testicular development and that it is enriched in spermatocytes. This, and phylogenetic analysis indicate a testis-specific function. We observed a modest reduction in meiotic recombination at a recombination hotspot in Poln-deficient mice. Pol ν has been suggested to function in DNA crosslink repair. However, we found no increased DNA crosslink sensitivity in Poln-deficient mice or POLN-depleted human cells. This is a major difference from some previous findings, and we support our conclusion by multiple experimental approaches, and by the very low or absent expression of functional pol ν in mammalian somatic cells. The present work represents the first description and comprehensive analysis of mice deficient in pol ν, and the first thorough phenotypic analysis in human cells.
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32
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Malaby AW, Martin SK, Wood RD, Doublié S. Expression and Structural Analyses of Human DNA Polymerase θ (POLQ). Methods Enzymol 2017; 592:103-121. [PMID: 28668117 PMCID: PMC5624038 DOI: 10.1016/bs.mie.2017.03.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
DNA polymerase theta (pol θ) is an evolutionarily conserved protein encoded by the POLQ gene in mammalian genomes. Pol θ is the defining enzyme for a pathway of DSB repair termed "alternative end-joining" (altEJ) or "theta-mediated end-joining." This pathway contributes significantly to the radiation resistance of mammalian cells. It also modulates accuracy in repair of breaks that occur at stalled DNA replication forks, during diversification steps of the mammalian immune system, during repair of CRISPR-Cas9, and in many DNA integration events. Pol θ is a potentially important clinical target, particularly for cancers deficient in other break repair strategies. The enzyme is uniquely able to mediate joining of single-stranded 3' ends. Because of these unusual biochemical properties and its therapeutic importance, it is essential to study structures of pol θ bound to DNA. However, challenges for expression and purification are presented by the large size of pol θ (2590 residues in humans) and unusual juxtaposition of domains (a helicase-like domain and distinct DNA polymerase, separated by a region predicted to be largely disordered). Here we summarize work on the expression and purification of the full-length protein, and then focus on the design, expression, and purification of an active C-terminal polymerase fragment. The generation of this active construct was nontrivial and time consuming. Almost all published biochemical work to date has been performed with this domain fragment. Strategies to obtain and improve crystals of a ternary pol θ complex (enzyme:DNA:nucleotide) are also presented, along with key elements of the structure.
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Affiliation(s)
| | - Sara K Martin
- The University of Texas MD Anderson Cancer Center, Smithville, TX, United States; MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Richard D Wood
- The University of Texas MD Anderson Cancer Center, Smithville, TX, United States; MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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33
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Dai CH, Chen P, Li J, Lan T, Chen YC, Qian H, Chen K, Li MY. Co-inhibition of pol θ and HR genes efficiently synergize with cisplatin to suppress cisplatin-resistant lung cancer cells survival. Oncotarget 2016; 7:65157-65170. [PMID: 27533083 PMCID: PMC5323145 DOI: 10.18632/oncotarget.11214] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/18/2016] [Indexed: 12/14/2022] Open
Abstract
Cisplatin exert its anticancer effect by creating intrastrand and interstrand DNA cross-links which block DNA replication and is a major drug used to treat lung cancer. However, the main obstacle of the efficacy of treatment is drug resistance. Here, we show that expression of translesion synthesis (TLS) polymerase Q (POLQ) was significantly elevated by exposure of lung cancer cells A549/DR (a cisplatin-resistant A549 cell line) to cisplatin. POLQ expression correlated inversely with homologous recombination (HR) activity. Co-depletion of BRCA2 and POLQ by siRNA markedly increased sensitivity of A549/DR cells to cisplatin, which was accompanied with impairment of double strand breaks (DSBs) repair reflected by prominent cell cycle checkpoint response, increased chromosomal aberrations and persistent colocalization of p-ATM and 53BP1 foci induced by cisplatin. Thus, co-knockdown of POLQ and HR can efficiently synergize with cisplatin to inhibit A549/DR cell survival by inhibiting DNA DSBs repair. Similar results were observed in A549/DR cells co-depleted of BRCA2 and POLQ following BMN673 (a PARP inhibitor) treatment. Importantly, the sensitization effects to cisplatin and BMN673 in A549/DR cells by co-depleting BRCA2 and POLQ was stronger than those by co-depleting BRCA2 and other TLS factors including POLH, REV3, or REV1. Our results indicate that there is a synthetic lethal relationship between pol θ-mediated DNA repair and HR pathways. Pol θ may be considered as a novel target for lung cancer therapy.
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Affiliation(s)
- Chun-Hua Dai
- Department of Radiation Oncology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ping Chen
- Department of Pulmonary Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Jian Li
- Department of Pulmonary Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Tin Lan
- Institute of Medical Science, Jiangsu University, Zhenjiang, China
| | - Yong-Chang Chen
- Institute of Medical Science, Jiangsu University, Zhenjiang, China
| | - Hai Qian
- Institute of Medical Science, Jiangsu University, Zhenjiang, China
| | - Kang Chen
- Department of Pulmonary Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Mei-Yu Li
- Department of Pulmonary Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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34
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Black SJ, Kashkina E, Kent T, Pomerantz RT. DNA Polymerase θ: A Unique Multifunctional End-Joining Machine. Genes (Basel) 2016; 7:E67. [PMID: 27657134 PMCID: PMC5042397 DOI: 10.3390/genes7090067] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/02/2016] [Accepted: 09/08/2016] [Indexed: 01/01/2023] Open
Abstract
The gene encoding DNA polymerase θ (Polθ) was discovered over ten years ago as having a role in suppressing genome instability in mammalian cells. Studies have now clearly documented an essential function for this unique A-family polymerase in the double-strand break (DSB) repair pathway alternative end-joining (alt-EJ), also known as microhomology-mediated end-joining (MMEJ), in metazoans. Biochemical and cellular studies show that Polθ exhibits a unique ability to perform alt-EJ and during this process the polymerase generates insertion mutations due to its robust terminal transferase activity which involves template-dependent and independent modes of DNA synthesis. Intriguingly, the POLQ gene also encodes for a conserved superfamily 2 Hel308-type ATP-dependent helicase domain which likely assists in alt-EJ and was reported to suppress homologous recombination (HR) via its anti-recombinase activity. Here, we review our current knowledge of Polθ-mediated end-joining, the specific activities of the polymerase and helicase domains, and put into perspective how this multifunctional enzyme promotes alt-EJ repair of DSBs formed during S and G2 cell cycle phases.
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Affiliation(s)
- Samuel J Black
- Fels Institute for Cancer Research, Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
| | - Ekaterina Kashkina
- Fels Institute for Cancer Research, Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
| | - Tatiana Kent
- Fels Institute for Cancer Research, Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
| | - Richard T Pomerantz
- Fels Institute for Cancer Research, Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
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Suzuki T, Grúz P, Honma M, Adachi N, Nohmi T. The role of DNA polymerase ζ in translesion synthesis across bulky DNA adducts and cross-links in human cells. Mutat Res 2016; 791-792:35-41. [PMID: 27591392 DOI: 10.1016/j.mrfmmm.2016.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 08/17/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Translesion DNA synthesis (TLS) is a cellular defense mechanism against genotoxins. Defects or mutations in specialized DNA polymerases (Pols) involved in TLS are believed to result in hypersensitivity to various genotoxic stresses. Here, DNA polymerase ζ (Pol ζ)-deficient (KO: knockout) and Pol ζ catalytically dead (CD) human cells were established and their sensitivity towards cytotoxic activities of various genotoxins was examined. The CD cells were engineered by altering the DNA sequence encoding two amino acids essential for the catalytic activity of Pol ζ, i.e., D2781 and D2783, to alanines. Both Pol ζ KO and CD cells displayed a prolonged cell cycle and higher incidence of micronuclei formation than the wild-type (WT) cells in the absence of exogenous genotoxic treatments, and the order of abnormality was CD>KO>WT cells. Both KO and CD cells exhibited higher sensitivity towards the killing effects of benzo[a]pyrene diol epoxide, mitomycin C, potassium bromate, N-methyl-N'-nitro-N-nitrosoguanidine, and ultraviolet C irradiation than WT cells, and there were no differences between the sensitivities of KO and CD cells. Interestingly, neither KO nor CD cells were sensitive to the cytotoxic effects of hydrogen peroxide. Since KO and CD cells displayed similar sensitivities to the genotoxins, we employed only KO cells to further examine their sensitivity to other genotoxic agents. KO cells were more sensitive to the cytotoxicity of 4-nitroquinoline N-oxide, styrene oxide, cisplatin, methyl methanesulfonate, and ethyl methanesulfonate than WT cells. However, the KO cells displayed sensitivity camptothecin, etoposide, bleomycin, hydroxyurea, crotonealdehyde, and methylglyoxal in a manner similar to the WT cells. Our results suggest that Pol ζ plays an important role in the protection of human cells by carrying out TLS across bulky DNA adducts and cross-links, but has no or limited role in the protection against strand-breaks in DNA.
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Affiliation(s)
- Tetsuya Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
| | - Petr Grúz
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Noritaka Adachi
- Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Abstract
DNA polymerase theta (pol θ) is encoded in the genomes of many eukaryotes, though not in fungi. Pol θ is encoded by the POLQ gene in mammalian cells. The C-terminal third of the protein is a family A DNA polymerase with additional insertion elements relative to prokaryotic homologs. The N-terminal third is a helicase-like domain with DNA-dependent ATPase activity. Pol θ is important in the repair of genomic double-strand breaks (DSBs) from many sources. These include breaks formed by ionizing radiation and topoisomerase inhibitors, breaks arising at stalled DNA replication forks, breaks introduced during diversification steps of the mammalian immune system, and DSB induced by CRISPR-Cas9. Pol θ participates in a route of DSB repair termed "alternative end-joining" (altEJ). AltEJ is independent of the DNA binding Ku protein complex and requires DNA end resection. Pol θ is able to mediate joining of two resected 3' ends harboring DNA sequence microhomology. "Signatures" of Pol θ action during altEJ are the frequent utilization of longer microhomologies, and the insertion of additional sequences at joining sites. The mechanism of end-joining employs the ability of Pol θ to tightly grasp a 3' terminus through unique contacts in the active site, allowing extension from minimally paired primers. Pol θ is involved in controlling the frequency of chromosome translocations and preserves genome integrity by limiting large deletions. It may also play a backup role in DNA base excision repair. POLQ is a member of a cluster of similarly upregulated genes that are strongly correlated with poor clinical outcome for breast cancer, ovarian cancer and other cancer types. Inhibition of pol θ is a compelling approach for combination therapy of radiosensitization.
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Affiliation(s)
- Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX 78957, USA; Graduate School of Biomedical Sciences at Houston, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA.
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Beagan K, McVey M. Linking DNA polymerase theta structure and function in health and disease. Cell Mol Life Sci 2016; 73:603-15. [PMID: 26514729 PMCID: PMC4715478 DOI: 10.1007/s00018-015-2078-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/10/2015] [Accepted: 10/19/2015] [Indexed: 10/22/2022]
Abstract
DNA polymerase theta (Pol θ) is an error-prone A-family polymerase that is highly conserved among multicellular eukaryotes and plays multiple roles in DNA repair and the regulation of genome integrity. Studies conducted in several model organisms have shown that Pol θ can be utilized during DNA interstrand crosslink repair and during alternative end-joining repair of double-strand breaks. Recent genetic and biochemical studies have begun to elucidate the unique structural features of Pol θ that promote alternative end-joining repair. Importantly, Pol θ-dependent end joining appears to be important for overall genome stability, as it affects chromosome translocation formation in murine and human cell lines. Pol θ has also been suggested to act as a modifier of replication timing in human cells, though the mechanism of action remains unknown. Pol θ is highly upregulated in a number of human cancer types, which could indicate that mutagenic Pol θ-dependent end joining is used during cancer cell proliferation. Here, we review the various roles of Pol θ across species and discuss how these roles may be relevant to cancer therapy.
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Affiliation(s)
- Kelly Beagan
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA, 02155, USA
| | - Mitch McVey
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA, 02155, USA.
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The Polymerase Activity of Mammalian DNA Pol ζ Is Specifically Required for Cell and Embryonic Viability. PLoS Genet 2016; 12:e1005759. [PMID: 26727495 PMCID: PMC4699697 DOI: 10.1371/journal.pgen.1005759] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/02/2015] [Indexed: 02/06/2023] Open
Abstract
DNA polymerase ζ (pol ζ) is exceptionally important for maintaining genome stability. Inactivation of the Rev3l gene encoding the polymerase catalytic subunit causes a high frequency of chromosomal breaks, followed by lethality in mouse embryos and in primary cells. Yet it is not known whether the DNA polymerase activity of pol ζ is specifically essential, as the large REV3L protein also serves as a multiprotein scaffold for translesion DNA synthesis via multiple conserved structural domains. We report that Rev3l cDNA rescues the genomic instability and DNA damage sensitivity of Rev3l-null immortalized mouse fibroblast cell lines. A cDNA harboring mutations of conserved catalytic aspartate residues in the polymerase domain of REV3L could not rescue these phenotypes. To investigate the role of REV3L DNA polymerase activity in vivo, a Rev3l knock-in mouse was constructed with this polymerase-inactivating alteration. No homozygous mutant mice were produced, with lethality occurring during embryogenesis. Primary fibroblasts from mutant embryos showed growth defects, elevated DNA double-strand breaks and cisplatin sensitivity similar to Rev3l-null fibroblasts. We tested whether the severe Rev3l-/- phenotypes could be rescued by deletion of DNA polymerase η, as has been reported with chicken DT40 cells. However, Rev3l-/-Polh-/- mice were inviable, and derived primary fibroblasts were as sensitive to DNA damage as Rev3l-/-Polh+/+ fibroblasts. Therefore, the functions of REV3L in maintaining cell viability, embryonic viability and genomic stability are directly dependent on its polymerase activity, and cannot be ameliorated by an additional deletion of pol η. These results validate and encourage the approach of targeting the DNA polymerase activity of pol ζ to sensitize tumors to DNA damaging agents. Translesion synthesis allows DNA replication to occur in the presence of damaged DNA. This process is mediated by low-fidelity DNA polymerases (such as pol ζ or pol η) that maintain genomic stability. The action of these polymerases is crucial to limit cancer. In mice, complete deletion of DNA pol ζ leads to embryonic lethality, and conditional deletion enhances tumorigenesis. Pol ζ is a large protein with many domains that interact with other essential proteins and maintain the structural integrity of pol ζ. It is not known if the polymerase activity of pol ζ mediates its essential activities. Using a cell culture complementation system and in vivo knock-in mice, our work shows that pol ζ–mediated maintenance of genomic stability in the presence of DNA damage is absolutely dependent on its DNA polymerase activity. Others have demonstrated in chicken cells that co-deletion of pol ζ and pol η rescues the pol ζ-dependent phenotypes, but our work in mice and in mouse cell culture does not support that conclusion. These results demonstrate the physiological importance of pol ζ polymerase activity, and show that employing small-molecule inhibitors of the polymerase reaction is a valid strategy for sensitizing tumor cells to chemotherapeutic agents.
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Newman JA, Cooper CDO, Aitkenhead H, Gileadi O. Structure of the Helicase Domain of DNA Polymerase Theta Reveals a Possible Role in the Microhomology-Mediated End-Joining Pathway. Structure 2015; 23:2319-2330. [PMID: 26636256 PMCID: PMC4671958 DOI: 10.1016/j.str.2015.10.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 12/21/2022]
Abstract
DNA polymerase theta (Polθ) has been identified as a crucial alternative non-homologous end-joining factor in mammalian cells. Polθ is upregulated in a range of cancer cell types defective in homologous recombination, and knockdown has been shown to inhibit cell survival in a subset of these, making it an attractive target for cancer treatment. We present crystal structures of the helicase domain of human Polθ in the presence and absence of bound nucleotides, and a characterization of its DNA-binding and DNA-stimulated ATPase activities. Comparisons with related helicases from the Hel308 family identify several unique features. Polθ exists as a tetramer both in the crystals and in solution. We propose a model for DNA binding to the Polθ helicase domain in the context of the Polθ tetramer, which suggests a role for the helicase domain in strand annealing of DNA templates for subsequent processing by the polymerase domain.
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Affiliation(s)
- Joseph A Newman
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Christopher D O Cooper
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Hazel Aitkenhead
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Opher Gileadi
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK.
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Zahn KE, Averill AM, Aller P, Wood RD, Doublié S. Human DNA polymerase θ grasps the primer terminus to mediate DNA repair. Nat Struct Mol Biol 2015; 22:304-11. [PMID: 25775267 PMCID: PMC4385486 DOI: 10.1038/nsmb.2993] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/13/2015] [Indexed: 01/14/2023]
Abstract
DNA polymerase θ protects against genomic instability via an alternative end-joining repair pathway for DNA double-strand breaks. Polymerase θ is overexpressed in breast, lung and oral cancers, and reduction of its activity in mammalian cells increases sensitivity to double-strand break-inducing agents, including ionizing radiation. Reported here are crystal structures of the C-terminal polymerase domain from human polymerase θ, illustrating two potential modes of dimerization. One structure depicts insertion of ddATP opposite an abasic-site analog during translesion DNA synthesis. The second structure describes a cognate ddGTP complex. Polymerase θ uses a specialized thumb subdomain to establish unique upstream contacts to the primer DNA strand, including an interaction with the 3'-terminal phosphate from one of five distinctive insertion loops. These observations demonstrate how polymerase θ grasps the primer to bypass DNA lesions or extend poorly annealed DNA termini to mediate end-joining.
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | - April M Averill
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | | | - Richard D Wood
- Department of Epigenetics &Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
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Brandalize APC, Schüler-Faccini L, Hoffmann JS, Caleffi M, Cazaux C, Ashton-Prolla P. A DNA repair variant in POLQ (c.-1060A > G) is associated to hereditary breast cancer patients: a case-control study. BMC Cancer 2014; 14:850. [PMID: 25409685 PMCID: PMC4246548 DOI: 10.1186/1471-2407-14-850] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 11/07/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND One of the hallmarks of cancer is the occurrence of high levels of chromosomal rearrangements as a result of inaccurate repair of double-strand breaks (DSB). Germline mutations in BRCA and RAD51 genes, involved in DSB repair, are strongly associated with hereditary breast cancer. Pol θ, a translesional DNA polymerase specialized in the replication of damaged DNA, has been also shown to contribute to DNA synthesis associated to DSB repair. It is noteworthy that POLQ is highly expressed in breast tumors and this expression is able to predict patient outcome. The objective of this study was to analyze genetic variants related to POLQ as new population biomarkers of risk in hereditary (HBC) and sporadic (SBC) breast cancer. METHODS We analyzed through case-control study nine SNPs of POLQ in hereditary (HBC) and sporadic (SBC) breast cancer patients using Taqman Real Time PCR assays. Polymorphisms were systematically identified through the NCBI database and are located within exons or promoter regions. We recruited 204 breast cancer patients (101 SBC and 103 HBC) and 212 unaffected controls residing in Southern Brazil. RESULTS The rs581553 SNP located in the promoter region was strongly associated with HBC (c.-1060A > G; HBC GG = 15, Control TT = 8; OR = 5.67, CI95% = 2.26-14.20; p < 0.0001). Interestingly, 11 of 15 homozygotes for this polymorphism fulfilled criteria for Hereditary Breast and Ovarian Cancer (HBOC) syndrome. Furthermore, 12 of them developed bilateral breast cancer and one had a familial history of bilateral breast cancer. This polymorphism was also associated with bilateral breast cancer in 67 patients (OR = 9.86, CI95% = 3.81-25.54). There was no statistically significant difference of age at breast cancer diagnosis between SNP carriers and non-carriers. CONCLUSIONS Considering that Pol θ is involved in DBS repair, our results suggest that this polymorphism may contribute to the etiology of HBC, particularly in patients with bilateral breast cancer.
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Affiliation(s)
- Ana Paula Carneiro Brandalize
- />Laboratory of Medical Genomics, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- />Laboratory of Genomics, Proteomics and DNA Repair, University of Caxias do Sul, Caxias do Sul, Brazil
- />Instituto Nacional de Genética Médica Populacional, INAGEMP, Porto Alegre, Brazil
| | - Lavínia Schüler-Faccini
- />Department of Genetics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
- />Instituto Nacional de Genética Médica Populacional, INAGEMP, Porto Alegre, Brazil
| | - Jean-Sébastien Hoffmann
- />Equipe « Labellisée Ligue contre le Cancer 2013 » INSERM Unit 1037; CNRS ERL 5294, CRCT (Cancer Research Center of Toulouse), Toulouse Oncopole, France
- />University of Toulouse; UPS, F-31077 Toulouse, France
| | | | - Christophe Cazaux
- />Equipe « Labellisée Ligue contre le Cancer 2013 » INSERM Unit 1037; CNRS ERL 5294, CRCT (Cancer Research Center of Toulouse), Toulouse Oncopole, France
- />University of Toulouse; UPS, F-31077 Toulouse, France
| | - Patricia Ashton-Prolla
- />Laboratory of Medical Genomics, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- />Department of Genetics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
- />Instituto Nacional de Genética Médica Populacional, INAGEMP, Porto Alegre, Brazil
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Yousefzadeh MJ, Wyatt DW, Takata KI, Mu Y, Hensley SC, Tomida J, Bylund GO, Doublié S, Johansson E, Ramsden DA, McBride KM, Wood RD. Mechanism of suppression of chromosomal instability by DNA polymerase POLQ. PLoS Genet 2014; 10:e1004654. [PMID: 25275444 PMCID: PMC4183433 DOI: 10.1371/journal.pgen.1004654] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/05/2014] [Indexed: 12/13/2022] Open
Abstract
Although a defect in the DNA polymerase POLQ leads to ionizing radiation sensitivity in mammalian cells, the relevant enzymatic pathway has not been identified. Here we define the specific mechanism by which POLQ restricts harmful DNA instability. Our experiments show that Polq-null murine cells are selectively hypersensitive to DNA strand breaking agents, and that damage resistance requires the DNA polymerase activity of POLQ. Using a DNA break end joining assay in cells, we monitored repair of DNA ends with long 3' single-stranded overhangs. End joining events retaining much of the overhang were dependent on POLQ, and independent of Ku70. To analyze the repair function in more detail, we examined immunoglobulin class switch joining between DNA segments in antibody genes. POLQ participates in end joining of a DNA break during immunoglobulin class-switching, producing insertions of base pairs at the joins with homology to IgH switch-region sequences. Biochemical experiments with purified human POLQ protein revealed the mechanism generating the insertions during DNA end joining, relying on the unique ability of POLQ to extend DNA from minimally paired primers. DNA breaks at the IgH locus can sometimes join with breaks in Myc, creating a chromosome translocation. We found a marked increase in Myc/IgH translocations in Polq-defective mice, showing that POLQ suppresses genomic instability and genome rearrangements originating at DNA double-strand breaks. This work clearly defines a role and mechanism for mammalian POLQ in an alternative end joining pathway that suppresses the formation of chromosomal translocations. Our findings depart from the prevailing view that alternative end joining processes are generically translocation-prone.
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Affiliation(s)
- Matthew J. Yousefzadeh
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, United States of America
| | - David W. Wyatt
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics and Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kei-ichi Takata
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, United States of America
| | - Yunxiang Mu
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
| | - Sean C. Hensley
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
| | - Junya Tomida
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, United States of America
| | - Göran O. Bylund
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, The University of Vermont, Burlington, Vermont
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Dale A. Ramsden
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics and Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kevin M. McBride
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, United States of America
| | - Richard D. Wood
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, United States of America
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Characterization of DNA repair deficient strains of Chlamydomonas reinhardtii generated by insertional mutagenesis. PLoS One 2014; 9:e105482. [PMID: 25144319 PMCID: PMC4140758 DOI: 10.1371/journal.pone.0105482] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/23/2014] [Indexed: 12/15/2022] Open
Abstract
While the mechanisms governing DNA damage response and repair are fundamentally conserved, cross-kingdom comparisons indicate that they differ in many aspects due to differences in life-styles and developmental strategies. In photosynthetic organisms these differences have not been fully explored because gene-discovery approaches are mainly based on homology searches with known DDR/DNA repair proteins. Here we performed a forward genetic screen in the green algae Chlamydomonas reinhardtii to identify genes deficient in DDR/DNA repair. We isolated five insertional mutants that were sensitive to various genotoxic insults and two of them exhibited altered efficiency of transgene integration. To identify genomic regions disrupted in these mutants, we established a novel adaptor-ligation strategy for the efficient recovery of the insertion flanking sites. Four mutants harbored deletions that involved known DNA repair factors, DNA Pol zeta, DNA Pol theta, SAE2/COM1, and two neighbouring genes encoding ERCC1 and RAD17. Deletion in the last mutant spanned two Chlamydomonas-specific genes with unknown function, demonstrating the utility of this approach for discovering novel factors involved in genome maintenance.
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Fernandez-Vidal A, Guitton-Sert L, Cadoret JC, Drac M, Schwob E, Baldacci G, Cazaux C, Hoffmann JS. A role for DNA polymerase θ in the timing of DNA replication. Nat Commun 2014; 5:4285. [PMID: 24989122 DOI: 10.1038/ncomms5285] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/03/2014] [Indexed: 01/01/2023] Open
Abstract
Although DNA polymerase θ (Pol θ) is known to carry out translesion synthesis and has been implicated in DNA repair, its physiological function under normal growth conditions remains unclear. Here we present evidence that Pol θ plays a role in determining the timing of replication in human cells. We find that Pol θ binds to chromatin during early G1, interacts with the Orc2 and Orc4 components of the Origin recognition complex and that the association of Mcm proteins with chromatin is enhanced in G1 when Pol θ is downregulated. Pol θ-depleted cells exhibit a normal density of activated origins in S phase, but early-to-late and late-to-early shifts are observed at a number of replication domains. Pol θ overexpression, on the other hand, causes delayed replication. Our results therefore suggest that Pol θ functions during the earliest steps of DNA replication and influences the timing of replication initiation.
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Affiliation(s)
- Anne Fernandez-Vidal
- 1] Equipe Labellisée Ligue contre le Cancer 2013 INSERM Unit 1037; CNRS ERL 5294; CRCT (Cancer Research Center of Toulouse), BP3028, CHU Purpan, Toulouse 31024, France [2] Université Paul Sabatier, University of Toulouse III, Toulouse F-31062, France [3]
| | - Laure Guitton-Sert
- 1] Equipe Labellisée Ligue contre le Cancer 2013 INSERM Unit 1037; CNRS ERL 5294; CRCT (Cancer Research Center of Toulouse), BP3028, CHU Purpan, Toulouse 31024, France [2] Université Paul Sabatier, University of Toulouse III, Toulouse F-31062, France [3]
| | - Jean-Charles Cadoret
- 1] Institut Jacques Monod, UMR7592, CNRS and University Paris-Diderot, 15 Rue Hélène Brion, Paris, Cedex 13 75205, France [2]
| | - Marjorie Drac
- Institut of Molecular Genetics, CNRS UMR5535 and University of Montpellier, Montpellier 34293, France
| | - Etienne Schwob
- Institut of Molecular Genetics, CNRS UMR5535 and University of Montpellier, Montpellier 34293, France
| | - Giuseppe Baldacci
- Institut Jacques Monod, UMR7592, CNRS and University Paris-Diderot, 15 Rue Hélène Brion, Paris, Cedex 13 75205, France
| | - Christophe Cazaux
- 1] Equipe Labellisée Ligue contre le Cancer 2013 INSERM Unit 1037; CNRS ERL 5294; CRCT (Cancer Research Center of Toulouse), BP3028, CHU Purpan, Toulouse 31024, France [2] Université Paul Sabatier, University of Toulouse III, Toulouse F-31062, France
| | - Jean-Sébastien Hoffmann
- 1] Equipe Labellisée Ligue contre le Cancer 2013 INSERM Unit 1037; CNRS ERL 5294; CRCT (Cancer Research Center of Toulouse), BP3028, CHU Purpan, Toulouse 31024, France [2] Université Paul Sabatier, University of Toulouse III, Toulouse F-31062, France
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Parsons JL, Nicolay NH, Sharma RA. Biological and therapeutic relevance of nonreplicative DNA polymerases to cancer. Antioxid Redox Signal 2013; 18:851-73. [PMID: 22794079 PMCID: PMC3557440 DOI: 10.1089/ars.2011.4203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Apart from surgical approaches, the treatment of cancer remains largely underpinned by radiotherapy and pharmacological agents that cause damage to cellular DNA, which ultimately causes cancer cell death. DNA polymerases, which are involved in the repair of cellular DNA damage, are therefore potential targets for inhibitors for improving the efficacy of cancer therapy. They can be divided, according to their main function, into two groups, namely replicative and nonreplicative enzymes. At least 15 different DNA polymerases, including their homologs, have been discovered to date, which vary considerably in processivity and fidelity. Many of the nonreplicative (specialized) DNA polymerases replicate DNA in an error-prone fashion, and they have been shown to participate in multiple DNA damage repair and tolerance pathways, which are often aberrant in cancer cells. Alterations in DNA repair pathways involving DNA polymerases have been linked with cancer survival and with treatment response to radiotherapy or to classes of cytotoxic drugs routinely used for cancer treatment, particularly cisplatin, oxaliplatin, etoposide, and bleomycin. Indeed, there are extensive preclinical data to suggest that DNA polymerase inhibition may prove to be a useful approach for increasing the effectiveness of therapies in patients with cancer. Furthermore, specialized DNA polymerases warrant examination of their potential use as clinical biomarkers to select for particular cancer therapies, to individualize treatment for patients.
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Affiliation(s)
- Jason L Parsons
- Cancer Research UK-Medical Research Council, Oncology Department, Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom
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46
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Yousefzadeh MJ, Wood RD. DNA polymerase POLQ and cellular defense against DNA damage. DNA Repair (Amst) 2013; 12:1-9. [PMID: 23219161 PMCID: PMC3534860 DOI: 10.1016/j.dnarep.2012.10.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 12/15/2022]
Abstract
In mammalian cells, POLQ (pol θ) is an unusual specialized DNA polymerase whose in vivo function is under active investigation. POLQ has been implicated by different experiments to play a role in resistance to ionizing radiation and defense against genomic instability, in base excision repair, and in immunological diversification. The protein is formed by an N-terminal helicase-like domain, a C-terminal DNA polymerase domain, and a large central domain that spans between the two. This arrangement is also found in the Drosophila Mus308 protein, which functions in resistance to DNA interstrand crosslinking agents. Homologs of POLQ and Mus308 are found in multicellular eukaryotes, including plants, but a comparison of phenotypes suggests that not all of these genes are functional orthologs. Flies defective in Mus308 are sensitive to DNA interstrand crosslinking agents, while mammalian cells defective in POLQ are primarily sensitive to DNA double-strand breaking agents. Cells from Polq(-/-) mice are hypersensitive to radiation and peripheral blood cells display increased spontaneous and ionizing radiation-induced levels of micronuclei (a hallmark of gross chromosomal aberrations), though mice apparently develop normally. Loss of POLQ in human and mouse cells causes sensitivity to ionizing radiation and other double strand breaking agents and increased DNA damage signaling. Retrospective studies of clinical samples show that higher levels of POLQ gene expression in breast and colorectal cancer are correlated with poorer outcomes for patients. A clear understanding of the mechanism of action and physiologic function of POLQ in the cell is likely to bear clinical relevance.
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Affiliation(s)
- Matthew J Yousefzadeh
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX 78957, USA
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Sharma S, Canman CE. REV1 and DNA polymerase zeta in DNA interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:725-40. [PMID: 23065650 PMCID: PMC5543726 DOI: 10.1002/em.21736] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 08/09/2012] [Accepted: 08/15/2012] [Indexed: 05/06/2023]
Abstract
DNA interstrand crosslinks (ICLs) are covalent linkages between two strands of DNA, and their presence interferes with essential metabolic processes such as transcription and replication. These lesions are extremely toxic, and their repair is essential for genome stability and cell survival. In this review, we will discuss how the removal of ICLs requires interplay between multiple genome maintenance pathways and can occur in the absence of replication (replication-independent ICL repair) or during S phase (replication-coupled ICL repair), the latter being the predominant pathway used in mammalian cells. It is now well recognized that translesion DNA synthesis (TLS), especially through the activities of REV1 and DNA polymerase zeta (Polζ), is necessary for both ICL repair pathways operating throughout the cell cycle. Recent studies suggest that the convergence of two replication forks upon an ICL initiates a cascade of events including unhooking of the lesion through the actions of structure-specific endonucleases, thereby creating a DNA double-stranded break (DSB). TLS across the unhooked lesion is necessary for restoring the sister chromatid before homologous recombination repair. Biochemical and genetic studies implicate REV1 and Polζ as being essential for performing lesion bypass across the unhooked crosslink, and this step appears to be important for subsequent events to repair the intermediate DSB. The potential role of Fanconi anemia pathway in the regulation of REV1 and Polζ-dependent TLS and the involvement of additional polymerases, including DNA polymerases kappa, nu, and theta, in the repair of ICLs is also discussed in this review.
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Affiliation(s)
- Shilpy Sharma
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
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Hogg M, Sauer-Eriksson AE, Johansson E. Promiscuous DNA synthesis by human DNA polymerase θ. Nucleic Acids Res 2012; 40:2611-22. [PMID: 22135286 PMCID: PMC3315306 DOI: 10.1093/nar/gkr1102] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 12/15/2022] Open
Abstract
The biological role of human DNA polymerase θ (POLQ) is not yet clearly defined, but it has been proposed to participate in several cellular processes based on its translesion synthesis capabilities. POLQ is a low-fidelity polymerase capable of efficient bypass of blocking lesions such as abasic sites and thymine glycols as well as extension of mismatched primer termini. Here, we show that POLQ possesses a DNA polymerase activity that appears to be template independent and allows efficient extension of single-stranded DNA as well as duplex DNA with either protruding or multiply mismatched 3'-OH termini. We hypothesize that this DNA synthesis activity is related to the proposed role for POLQ in the repair or tolerance of double-strand breaks.
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Affiliation(s)
- Matthew Hogg
- Department of Medical Biochemistry and Biophysics and Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - A. Elisabeth Sauer-Eriksson
- Department of Medical Biochemistry and Biophysics and Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics and Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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Li Y, Gao X, Wang JY. Comparison of two POLQ mutants reveals that a polymerase-inactive POLQ retains significant function in tolerance to etoposide and γ-irradiation in mouse B cells. Genes Cells 2011; 16:973-83. [PMID: 21883722 DOI: 10.1111/j.1365-2443.2011.01550.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
DNA polymerase θ (POLQ) is a family A polymerase that contains an intrinsic helicase domain. POLQ has been implicated in tolerance to DNA damage but whether this depends solely on its polymerase domain remains unknown. In this study, we generated POLQ-null CH12F3 B cells by gene targeting and compared their sensitivity to DNA-damaging agents with previously established POLQ-inactive CH12F3 cells in which only the polymerase core domain was deleted. Compared with WT cells, POLQ-null and POLQ-inactive cells exhibited similarly increased sensitivity to mitomycin C, cisplatin, and ultraviolet radiation, suggesting that tolerance to these DNA-damaging agents depends largely on POLQ polymerase activity. Intriguingly, POLQ-null cells exhibited higher sensitivity than did POLQ-inactive cells to etoposide and γ-irradiation, both of which induce double-strand breaks (DSBs). This observation indicates that the polymerase-deleted POLQ, expressed in POLQ-inactive cells, retains significant function in tolerance to these agents. Class switch recombination of immunoglobulin genes, which involves repair of activation-induced cytidine deaminase (AID)-triggered DSBs, however, was unaffected in both POLQ-null and POLQ-inactive cells. These results suggest that the polymerase and other functional domains of POLQ both play important roles in tolerance to etoposide and γ-irradiation but are dispensable for AID-mediated class switch recombination.
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Affiliation(s)
- Yingqian Li
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Medical School of Nanjing University, China
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An YS, Lee E, Kang MH, Hong HS, Kim MR, Jang WS, Son Y, Yi JY. Substance P stimulates the recovery of bone marrow after the irradiation. J Cell Physiol 2011; 226:1204-13. [DOI: 10.1002/jcp.22447] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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