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Galant N, Krawczyk P, Monist M, Obara A, Gajek Ł, Grenda A, Nicoś M, Kalinka E, Milanowski J. Molecular Classification of Endometrial Cancer and Its Impact on Therapy Selection. Int J Mol Sci 2024; 25:5893. [PMID: 38892080 PMCID: PMC11172295 DOI: 10.3390/ijms25115893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/21/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Endometrial cancer (EC) accounts for 90% of uterine cancer cases. It is considered not only one of the most common gynecological malignancies but also one of the most frequent cancers among women overall. Nowadays, the differentiation of EC subtypes is based on immunohistochemistry and molecular techniques. It is considered that patients' prognosis and the implementation of the appropriate treatment depend on the cancer subtype. Patients with pathogenic variants in POLE have the most favorable outcome, while those with abnormal p53 protein have the poorest. Therefore, in patients with POLE mutation, the de-escalation of postoperative treatment may be considered, and patients with abnormal p53 protein should be subjected to intensive adjuvant therapy. Patients with a DNA mismatch repair (dMMR) deficiency are classified in the intermediate prognosis group as EC patients without a specific molecular profile. Immunotherapy has been recognized as an effective treatment method in patients with advanced or recurrent EC with a mismatch deficiency. Thus, different adjuvant therapy approaches, including targeted therapy and immunotherapy, are being proposed depending on the EC subtype, and international guidelines, such as those published by ESMO and ESGO/ESTRO/ESP, include recommendations for performing the molecular classification of all EC cases. The decision about adjuvant therapy selection has to be based not only on clinical data and histological type and stage of cancer, but, following international recommendations, has to include EC molecular subtyping. This review describes how molecular classification could support more optimal therapeutic management in endometrial cancer patients.
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Affiliation(s)
- Natalia Galant
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; (N.G.); (P.K.); (M.N.); (J.M.)
| | - Paweł Krawczyk
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; (N.G.); (P.K.); (M.N.); (J.M.)
| | - Marta Monist
- II Department of Gynecology, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Adrian Obara
- Institute of Genetics and Immunology GENIM LCC, 20-609 Lublin, Poland; (A.O.); (Ł.G.)
| | - Łukasz Gajek
- Institute of Genetics and Immunology GENIM LCC, 20-609 Lublin, Poland; (A.O.); (Ł.G.)
| | - Anna Grenda
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; (N.G.); (P.K.); (M.N.); (J.M.)
| | - Marcin Nicoś
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; (N.G.); (P.K.); (M.N.); (J.M.)
| | - Ewa Kalinka
- Department of Oncology, Polish Mother’s Memorial Hospital-Research Institute, 93-338 Łódź, Poland;
| | - Janusz Milanowski
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; (N.G.); (P.K.); (M.N.); (J.M.)
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2
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Thomas C, Avalos-Irving L, Victorino J, Green S, Andrews M, Rodrigues N, Ebirim S, Mudd A, Towle-Weicksel JB. Melanoma-Derived DNA Polymerase Theta Variants Exhibit Altered DNA Polymerase Activity. Biochemistry 2024; 63:1107-1117. [PMID: 38671548 PMCID: PMC11080051 DOI: 10.1021/acs.biochem.3c00670] [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: 11/29/2023] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024]
Abstract
DNA polymerase θ (Pol θ or POLQ) is primarily involved in repairing double-stranded breaks in DNA through an alternative pathway known as microhomology-mediated end joining (MMEJ) or theta-mediated end joining (TMEJ). Unlike other DNA repair polymerases, Pol θ is thought to be highly error-prone yet critical for cell survival. We have identified several POLQ gene variants from human melanoma tumors that experience altered DNA polymerase activity, including a propensity for incorrect nucleotide selection and reduced polymerization rates compared to WT Pol θ. Variants are 30-fold less efficient at incorporating a nucleotide during repair and up to 70-fold less accurate at selecting the correct nucleotide opposite a templating base. This suggests that aberrant Pol θ has reduced DNA repair capabilities and may also contribute to increased mutagenesis. Moreover, the variants were identified in established tumors, suggesting that cancer cells may use mutated polymerases to promote metastasis and drug resistance.
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Affiliation(s)
- Corey Thomas
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Lisbeth Avalos-Irving
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Jorge Victorino
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Sydney Green
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Morgan Andrews
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Naisha Rodrigues
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Sarah Ebirim
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Ayden Mudd
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Jamie B. Towle-Weicksel
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
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3
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Baranovskiy AG, Morstadt LM, Babayeva ND, Tahirov TH. Human primosome requires replication protein A when copying DNA with inverted repeats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584335. [PMID: 38559116 PMCID: PMC10979909 DOI: 10.1101/2024.03.11.584335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The human primosome, a four-subunit complex of primase and DNA polymerase alpha (Polα), initiates DNA synthesis on both chromosome strands by generating chimeric RNA-DNA primers for loading DNA polymerases delta and epsilon (Polε). Replication protein A (RPA) tightly binds to single-stranded DNA strands, protecting them from nucleolytic digestion and unauthorized transactions. We report here that RPA plays a critical role for the human primosome during DNA synthesis across inverted repeats prone to hairpin formation. On other alternatively structured DNA forming a G-quadruplex, RPA provides no assistance for primosome. A stimulatory effect of RPA on DNA synthesis across hairpins was also observed for the catalytic domain of Polα but not of Polε. The important factors for an efficient hairpin bypass by primosome are the high affinity of RPA to DNA based on four DNA-binding domains and the interaction of the winged-helix-turn-helix domain of RPA with Polα. Binding studies indicate that this interaction stabilizes the RPA/Polα complex on the primed template. This work provides insight into a cooperative action of RPA and primosome on DNA, which is critical for DNA synthesis across inverted repeats.
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4
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Shah SM, Demidova EV, Ringenbach S, Faezov B, Andrake M, Gandhi A, Mur P, Viana-Errasti J, Xiu J, Swensen J, Valle L, Dunbrack RL, Hall MJ, Arora S. Exploring Co-occurring POLE Exonuclease and Non-exonuclease Domain Mutations and Their Impact on Tumor Mutagenicity. CANCER RESEARCH COMMUNICATIONS 2024; 4:213-225. [PMID: 38282550 PMCID: PMC10812383 DOI: 10.1158/2767-9764.crc-23-0312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/05/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
POLE driver mutations in the exonuclease domain (ExoD driver) are prevalent in several cancers, including colorectal cancer and endometrial cancer, leading to dramatically ultra-high tumor mutation burden (TMB). To understand whether POLE mutations that are not classified as drivers (POLE Variant) contribute to mutagenesis, we assessed TMB in 447 POLE-mutated colorectal cancers, endometrial cancers, and ovarian cancers classified as TMB-high ≥10 mutations/Mb (mut/Mb) or TMB-low <10 mut/Mb. TMB was significantly highest in tumors with "POLE ExoD driver plus POLE Variant" (colorectal cancer and endometrial cancer, P < 0.001; ovarian cancer, P < 0.05). TMB increased with additional POLE variants (P < 0.001), but plateaued at 2, suggesting an association between the presence of these variants and TMB. Integrated analysis of AlphaFold2 POLE models and quantitative stability estimates predicted the impact of multiple POLE variants on POLE functionality. The prevalence of immunogenic neoepitopes was notably higher in the "POLE ExoD driver plus POLE Variant" tumors. Overall, this study reveals a novel correlation between POLE variants in POLE ExoD-driven tumors, and ultra-high TMB. Currently, only select pathogenic ExoD mutations with a reliable association with ultra-high TMB inform clinical practice. Thus, these findings are hypothesis-generating, require functional validation, and could potentially inform tumor classification, treatment responses, and clinical outcomes. SIGNIFICANCE Somatic POLE ExoD driver mutations cause proofreading deficiency that induces high TMB. This study suggests a novel modifier role for POLE variants in POLE ExoD-driven tumors, associated with ultra-high TMB. These data, in addition to future functional studies, may inform tumor classification, therapeutic response, and patient outcomes.
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Affiliation(s)
- Shreya M. Shah
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Science Scholars Program, Temple University, Philadelphia, Pennsylvania
| | - Elena V. Demidova
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
| | - Salena Ringenbach
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Lewis Katz School of Medicine, Temple University, Bethlehem, Pennsylvania
| | - Bulat Faezov
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
- Program in Cancer Signaling and Microenvironment, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Mark Andrake
- Program in Cancer Signaling and Microenvironment, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Arjun Gandhi
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- University College Dublin School of Medicine and Medical Science, Dublin, Ireland
| | - Pilar Mur
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Julen Viana-Errasti
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | | | | | - Laura Valle
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Roland L. Dunbrack
- Program in Cancer Signaling and Microenvironment, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Michael J. Hall
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Sanjeevani Arora
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
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Tang M, Yin S, Zeng H, Huang A, Huang Y, Hu Z, Shah AR, Zhang S, Li H, Chen G. The P286R mutation of DNA polymerase ε activates cancer-cell-intrinsic immunity and suppresses endometrial tumorigenesis via the cGAS-STING pathway. Cell Death Dis 2024; 15:69. [PMID: 38238314 PMCID: PMC10796917 DOI: 10.1038/s41419-023-06418-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/22/2024]
Abstract
Endometrial carcinoma (EC) is a prevalent gynecological tumor in women, and its treatment and prevention are significant global health concerns. The mutations in DNA polymerase ε (POLE) are recognized as key features of EC and may confer survival benefits in endometrial cancer patients undergoing anti-PD-1/PD-L1 therapy. However, the anti-tumor mechanism of POLE mutations remains largely elusive. This study demonstrates that the hot POLE P286R mutation impedes endometrial tumorigenesis by inducing DNA breakage and activating the cGAS-STING signaling pathway. The POLE mutations were found to inhibit the proliferation and stemness of primary human EC cells. Mechanistically, the POLE mutants enhance DNA damage and suppress its repair through the interaction with DNA repair proteins, leading to genomic instability and the upregulation of cytoplasmic DNA. Additionally, the POLE P286R mutant also increases cGAS level, promotes TBK1 phosphorylation, and stimulates inflammatory gene expression and anti-tumor immune response. Furthermore, the POLE P286R mutation inhibits tumor growth and facilitates the infiltration of cytotoxic T cells in human endometrial cancers. These findings uncover a novel mechanism of POLE mutations in antagonizing tumorigenesis and provide a promising direction for effective cancer therapy.
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Affiliation(s)
- Ming Tang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Shasha Yin
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Hongliang Zeng
- Center of Medical Laboratory Animal, Hunan Academy of Chinese Medicine, Changsha, 410013, China
| | - Ao Huang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
- Center of Medical Laboratory Animal, Hunan Academy of Chinese Medicine, Changsha, 410013, China
| | - Yujia Huang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Zhiyi Hu
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Ab Rauf Shah
- Department of Pathology and Microbiology, UNMC, Omaha, USA
| | - Shuyong Zhang
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Gannan Medical University, Ministry of Education, Ganzhou, 341000, China.
- School of Basic Medicine, Gannan Medical University, Ganzhou, 341000, China.
| | - Haisen Li
- School of Life Sciences, Fudan University, Shanghai, 200438, China.
- AoBio Medical Co., Shanghai, 200438, China.
| | - Guofang Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China.
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6
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Selves J, de Castro E Gloria H, Brunac AC, Saffi J, Guimbaud R, Brousset P, Hoffmann JS. Exploring the basis of heterogeneity of cancer aggressiveness among the mutated POLE variants. Life Sci Alliance 2024; 7:e202302290. [PMID: 37891003 PMCID: PMC10610022 DOI: 10.26508/lsa.202302290] [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: 07/25/2023] [Revised: 10/04/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Germline pathogenic variants in the exonuclease domain of the replicative DNA polymerase Pol ε encoded by the POLE gene, predispose essentially to colorectal and endometrial tumors by inducing an ultramutator phenotype. It is still unclear whether all the POLE alterations influence similar strength tumorigenesis, immune microenvironment, and treatment response. In this review, we summarize the current understanding of the mechanisms and consequences of POLE mutations in human malignancies; we highlight the heterogeneity of mutation rate and cancer aggressiveness among POLE variants, propose some mechanistic basis underlining such heterogeneity, and discuss novel considerations for the choice and efficacy of therapies of POLE tumors.
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Affiliation(s)
- Janick Selves
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
| | - Helena de Castro E Gloria
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - Anne-Cécile Brunac
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
| | - Jenifer Saffi
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - Rosine Guimbaud
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
- Department of Digestive Oncology, Centre Hospitalier Universitaire (CHU), Toulouse, France
- Department of Digestive Surgery, Centre Hospitalier Universitaire (CHU), Toulouse, France
| | - Pierre Brousset
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Jean-Sébastien Hoffmann
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
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7
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Lewis JS, van Oijen AM, Spenkelink LM. Embracing Heterogeneity: Challenging the Paradigm of Replisomes as Deterministic Machines. Chem Rev 2023; 123:13419-13440. [PMID: 37971892 PMCID: PMC10790245 DOI: 10.1021/acs.chemrev.3c00436] [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: 06/25/2023] [Revised: 10/15/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
The paradigm of cellular systems as deterministic machines has long guided our understanding of biology. Advancements in technology and methodology, however, have revealed a world of stochasticity, challenging the notion of determinism. Here, we explore the stochastic behavior of multi-protein complexes, using the DNA replication system (replisome) as a prime example. The faithful and timely copying of DNA depends on the simultaneous action of a large set of enzymes and scaffolding factors. This fundamental cellular process is underpinned by dynamic protein-nucleic acid assemblies that must transition between distinct conformations and compositional states. Traditionally viewed as a well-orchestrated molecular machine, recent experimental evidence has unveiled significant variability and heterogeneity in the replication process. In this review, we discuss recent advances in single-molecule approaches and single-particle cryo-EM, which have provided insights into the dynamic processes of DNA replication. We comment on the new challenges faced by structural biologists and biophysicists as they attempt to describe the dynamic cascade of events leading to replisome assembly, activation, and progression. The fundamental principles uncovered and yet to be discovered through the study of DNA replication will inform on similar operating principles for other multi-protein complexes.
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Affiliation(s)
- Jacob S. Lewis
- Macromolecular
Machines Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Antoine M. van Oijen
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Lisanne M. Spenkelink
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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8
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Crevel G, Kearsey S, Cotterill S. A simple bypass assay for DNA polymerases shows that cancer-associated hypermutating variants exhibit differences in vitro. FEBS J 2023; 290:5744-5758. [PMID: 37592814 PMCID: PMC10953417 DOI: 10.1111/febs.16936] [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: 04/26/2023] [Revised: 07/13/2023] [Accepted: 08/16/2023] [Indexed: 08/19/2023]
Abstract
Errors made by DNA polymerases contribute to both natural variation and, in extreme cases, genome instability and its associated diseases. Recently, the importance of polymerase misincorporation in disease has been highlighted by the identification of cancer-associated polymerase variants with mutations in the exonuclease domain. A subgroup of these variants have a hypermutation phenotype in tumours, and when modelled in yeast, they show mutation rates in excess of that seen with polymerase with simple loss of proofreading activity. We have developed a bypass assay to rapidly determine the tendency of a polymerase to misincorporate in vitro. We have used the assay to compare misincorporation by wild-type, exonuclease-defective and two hypermutating human DNA polymerase ε variants, P286R and V411L. The assay clearly distinguished between the misincorporation rates of wild-type, exonuclease dead and P286R polymerases. However, the V411L polymerase showed misincorporation rate comparable to the exonuclease dead enzyme rather than P286R, suggesting that there may be some differences in the way that these variants cause hypermutation. Using this assay, misincorporation opposite a templated C nucleotide was consistently higher than for other nucleotides, and this caused predominantly C-to-T transitions. This is consistent with the observation that C-to-T transitions are commonly seen in DNA polymerase ε mutant tumours.
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9
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Thomas C, Avalos-Irving L, Victorino J, Green S, Andrews M, Rodrigues N, Ebirim S, Mudd A, Towle-Weicksel JB. Melanoma-derived DNA polymerase theta variants exhibit altered DNA polymerase activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566933. [PMID: 38014040 PMCID: PMC10680777 DOI: 10.1101/2023.11.14.566933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
DNA Polymerase θ (Pol θ or POLQ) is primarily involved in repairing double-stranded breaks in DNA through the alternative pathway known as microhomology-mediated end joining (MMEJ) or theta-mediated end joining (TMEJ). Unlike other DNA repair polymerases, Pol θ is thought to be highly error prone, yet critical for cell survival. We have identified several mutations in the POLQ gene from human melanoma tumors. Through biochemical analysis, we have demonstrated that all three cancer-associated variants experienced altered DNA polymerase activity including a propensity for incorrect nucleotide selection and reduced polymerization rates compared to WT Pol θ. Moreover, the variants are 30 fold less efficient at incorporating a nucleotide during repair and up to 70 fold less accurate at selecting the correct nucleotide opposite a templating base. Taken together, this suggests that aberrant Pol θ has reduced DNA repair capabilities and may also contribute to increased mutagenesis. While this may be beneficial to normal cell survival, the variants were identified in established tumors suggesting that cancer cells may use this promiscuous polymerase to its advantage to promote metastasis and drug resistance.
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10
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Strauss JD, Pursell ZF. Replication DNA polymerases, genome instability and cancer therapies. NAR Cancer 2023; 5:zcad033. [PMID: 37388540 PMCID: PMC10304742 DOI: 10.1093/narcan/zcad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/24/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023] Open
Abstract
It has been over a decade since the initial identification of exonuclease domain mutations in the genes encoding the catalytic subunits of replication DNA polymerases ϵ and δ (POLE and POLD1) in tumors from highly mutated endometrial and colorectal cancers. Interest in studying POLE and POLD1 has increased significantly since then. Prior to those landmark cancer genome sequencing studies, it was well documented that mutations in replication DNA polymerases that reduced their DNA synthesis accuracy, their exonuclease activity or their interactions with other factors could lead to increased mutagenesis, DNA damage and even tumorigenesis in mice. There are several recent, well-written reviews of replication DNA polymerases. The aim of this review is to gather and review in some detail recent studies of DNA polymerases ϵ and δ as they pertain to genome instability, cancer and potential therapeutic treatments. The focus here is primarily on recent informative studies on the significance of mutations in genes encoding their catalytic subunits (POLE and POLD1), mutational signatures, mutations in associated genes, model organisms, and the utility of chemotherapy and immune checkpoint inhibition in polymerase mutant tumors.
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Affiliation(s)
- Juliet D Strauss
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, 70118 LA, USA
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, 70118 LA, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, 70118 LA, USA
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11
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Labrousse G, Vande Perre P, Parra G, Jaffrelot M, Leroy L, Chibon F, Escudie F, Selves J, Hoffmann JS, Guimbaud R, Lutzmann M. The hereditary N363K POLE exonuclease mutant extends PPAP tumor spectrum to glioblastomas by causing DNA damage and aneuploidy in addition to increased mismatch mutagenicity. NAR Cancer 2023; 5:zcad011. [PMID: 36915289 PMCID: PMC10006997 DOI: 10.1093/narcan/zcad011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 01/27/2023] [Accepted: 02/22/2023] [Indexed: 03/13/2023] Open
Abstract
The exonuclease domain of DNA polymerases epsilon's catalytic subunit (POLE) removes misincorporated nucleotides, called proofreading. POLE-exonuclease mutations cause colorectal- and endometrial cancers with an extreme burden of single nucleotide substitutions. We recently reported that particularly the hereditary POLE exonuclease mutation N363K predisposes in addition to aggressive giant cell glioblastomas. We knocked-in this mutation homozygously into human cell lines and compared its properties to knock-ins of the likewise hereditary POLE L424V mutation and to a complete proofreading-inactivating mutation (exo-null). We found that N363K cells have higher mutation rates as both L424V- or exo-null mutant cells. In contrast to L424V cells, N363K cells expose a growth defect, replication stress and DNA damage. In non-transformed cells, these burdens lead to aneuploidy but macroscopically normal nuclei. In contrast, transformed N363K cells phenocopy the enlarged and disorganized nuclei of giant cell glioblastomas. Taken together, our data characterize a POLE exonuclease domain mutant that not only causes single nucleotide hypermutation, but in addition DNA damage and chromosome instability, leading to an extended tumor spectrum. Our results expand the understanding of the polymerase exonuclease domain and suggest that an assessment of both the mutational potential and the genetic instability might refine classification and treatment of POLE-mutated tumors.
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Affiliation(s)
- Guillaume Labrousse
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
| | - Pierre Vande Perre
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
- Oncogenetics Department, Institute Claudius Regaud, IUCT-Oncopole, Toulouse, France
| | - Genis Parra
- Center for Genomic Analysis, CNAG, Carrer de Baldiri Reixac 4, Barcelona, Spain
| | - Marion Jaffrelot
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
- Oncogenetics Department, Institute Claudius Regaud, IUCT-Oncopole, Toulouse, France
- Department of Digestive Oncology, IUCT Rangueil-Larrey, CHU de Toulouse, Toulouse, France
| | - Laura Leroy
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
| | - Frederic Chibon
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
| | - Frederic Escudie
- Laboratoire d’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irene-Joliot-Curie, 31059Toulouse, France
| | - Janick Selves
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
- Laboratoire d’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irene-Joliot-Curie, 31059Toulouse, France
| | - Jean-Sebastien Hoffmann
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
- Laboratoire d’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irene-Joliot-Curie, 31059Toulouse, France
| | - Rosine Guimbaud
- Oncogenetics Department, Institute Claudius Regaud, IUCT-Oncopole, Toulouse, France
- Department of Digestive Oncology, IUCT Rangueil-Larrey, CHU de Toulouse, Toulouse, France
| | - Malik Lutzmann
- Cancer Research Center of Toulouse, CRCT, 2 Avenue Hubert Curien, 31000Toulouse, France
- Institute of Human Genetics, IGH, UMR 9002, Centre National de la Recherche Scientifique, University of Montpellier, 34396Montpellier, France
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12
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Washif M, Ahmad T, Hosen MB, Rahman MR, Taniguchi T, Okubo H, Hirota K, Kawasumi R. CTF18-RFC contributes to cellular tolerance against chain-terminating nucleoside analogs (CTNAs) in cooperation with proofreading exonuclease activity of DNA polymerase ε. DNA Repair (Amst) 2023; 127:103503. [PMID: 37099849 DOI: 10.1016/j.dnarep.2023.103503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 04/28/2023]
Abstract
Chemotherapeutic nucleoside analogs, such as cytarabine (Ara-C), are incorporated into genomic DNA during replication. Incorporated Ara-CMP (Ara-cytidine monophosphate) serves as a chain terminator and inhibits DNA synthesis by replicative polymerase epsilon (Polε). The proofreading exonuclease activity of Polε removes the misincorporated Ara-CMP, thereby contributing to the cellular tolerance to Ara-C. Purified Polε performs proofreading, and it is generally believed that proofreading in vivo does not need additional factors. In this study, we demonstrated that the proofreading by Polε in vivo requires CTF18, a component of the leading-strand replisome. We found that loss of CTF18 in chicken DT40 cells and human TK6 cells results in hypersensitivity to Ara-C, indicating the conserved function of CTF18 in the cellular tolerance of Ara-C. Strikingly, we found that proofreading-deficient POLE1D269A/-, CTF18-/-, and POLE1D269A/-/CTF18-/- cells showed indistinguishable phenotypes, including the extent of hypersensitivity to Ara-C and decreased replication rate with Ara-C. This observed epistatic relationship between POLE1D269A/- and CTF18-/- suggests that they are interdependent in removing mis-incorporated Ara-CMP from the 3' end of primers. Mechanistically, we found that CTF18-/- cells have reduced levels of chromatin-bound Polε upon Ara-C treatment, suggesting that CTF18 contributes to the tethering of Polε on fork at the stalled end and thereby facilitating the removal of inserted Ara-C. Collectively, these data reveal the previously unappreciated role of CTF18 in Polε-exonuclease-mediated maintenance of the replication fork upon Ara-C incorporation.
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Affiliation(s)
- Mubasshir Washif
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Tasnim Ahmad
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Md Bayejid Hosen
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Md Ratul Rahman
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Tomoya Taniguchi
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Hiromori Okubo
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Ryotaro Kawasumi
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
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13
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Meng X, Claussin C, Regan-Mochrie G, Whitehouse I, Zhao X. Balancing act of a leading strand DNA polymerase-specific domain and its exonuclease domain promotes genome-wide sister replication fork symmetry. Genes Dev 2023; 37:74-79. [PMID: 36702483 PMCID: PMC10069448 DOI: 10.1101/gad.350054.122] [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: 08/26/2022] [Accepted: 12/19/2022] [Indexed: 01/28/2023]
Abstract
Pol2 is the leading-strand DNA polymerase in budding yeast. Here we describe an antagonism between its conserved POPS (Pol2 family-specific catalytic core peripheral subdomain) and exonuclease domain and the importance of this antagonism in genome replication. We show that multiple defects caused by POPS mutations, including impaired growth and DNA synthesis, genome instability, and reliance on other genome maintenance factors, were rescued by exonuclease inactivation. Single-molecule data revealed that the rescue stemmed from allowing sister replication forks to progress at equal rates. Our data suggest that balanced activity of Pol2's POPS and exonuclease domains is vital for genome replication and stability.
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Affiliation(s)
- Xiangzhou Meng
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Clémence Claussin
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Gemma Regan-Mochrie
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Iestyn Whitehouse
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA;
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA;
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14
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Tian W, Ji Z, Wang J, Meng J, Bi R, Ren Y, Shan B, Yang G, Wang H. Characterization of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene in endometrial cancer. Front Oncol 2022; 12:1018034. [PMID: 36313640 PMCID: PMC9596989 DOI: 10.3389/fonc.2022.1018034] [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: 08/12/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveThis study was aimed to profile hotspot exonuclease domain mutations (EDMs) of the DNA polymerase ϵ gene (POLE) in endometrial cancer (EC) and to investigate the effects of EDMs on tumor cell behavior and catalytic activities of Polϵ.MethodsPOLE sequencing was performed in tumor tissue samples from patients with EC to identify hotspot EDMs. Bioinformatics tools were used to select the potential pathogenic EDMs. The association of EDMs with the clinical outcomes of patients was assessed. EC cells were transfected with wildtype POLE or POLE variants to examine the effects of the EDMs on EC cell behavior, including cell cycle, migration, and invasion. Co-immunoprecipitation was employed to obtain FLAG-tagged wildtype and mutant catalytic subunits of Polϵ, followed by the assessment of polymerase and exonuclease activities.ResultsIn addition to previously reported P286R and V411L, R375Q and P452L were identified as novel, and deleterious POLE hotspot EDMs of EC. Patients in EDM group had significantly better clinical outcomes than the rest of the cohort. Compared with wildtype POLE, overexpression of POLE variants promoted cisplatin resistance, G0/G1 cell cycle arrest, and cell migration and invasion in EC cells. Overexpression of POLE variants significantly increased the abundance of 3’-OH and upregulated the expression of DNA mismatch repair genes in HEK293T cells. Compared with wildtype Polϵ, Pol ϵ mutants exhibited undermined polymerase and exonuclease abilities in the presence of mismatched nucleotides in HEK293 cells.ConclusionWe characterized the of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene and identified P286R, V411L, R375Q, and P452L as pathogenic POLE hotspot EDMs in endometrial cancer. These hotspot EDMs are associated with the malignant behavior of endometrial cancer cells in vitro and favorable prognosis in patients, suggesting that POLE affects a wide range of cellular processes beyond DNA replication and proofreading.
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Affiliation(s)
- Wenjuan Tian
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zhaodong Ji
- Department of Clinical Laboratory, Huashan Hospital, Fudan University, Shanghai, China
| | - Jingshu Wang
- Central Laboratory, The Fifth People’s Hospital of Shanghai, Fudan University, Shanghai, China
| | - Jiao Meng
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Rui Bi
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Yulan Ren
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Boer Shan
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Gong Yang
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Central Laboratory, The Fifth People’s Hospital of Shanghai, Fudan University, Shanghai, China
- Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China
- *Correspondence: Huaying Wang, ; Gong Yang,
| | - Huaying Wang
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- *Correspondence: Huaying Wang, ; Gong Yang,
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15
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The mismatch recognition protein MutSα promotes nascent strand degradation at stalled replication forks. Proc Natl Acad Sci U S A 2022; 119:e2201738119. [PMID: 36161943 PMCID: PMC9546528 DOI: 10.1073/pnas.2201738119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA mismatch repair (MMR) is well known for its role in maintaining replication fidelity by correcting mispairs generated during replication. Here, we identify an unusual MMR function to promote genome instability in the replication stress response. Under replication stress, binding of the mismatch recognition protein MutSα to replication forks blocks the loading of fork protection factors FANCD2 and BRCA1 to replication forks and promotes the recruitment of exonuclease MRE11 onto DNA to nascent strand degradation. This MutSα-dependent MRE11-catalyzed DNA degradation causes DNA breaks and chromosome abnormalities, contributing to an ultramutator phenotype. Mismatch repair (MMR) is a replication-coupled DNA repair mechanism and plays multiple roles at the replication fork. The well-established MMR functions include correcting misincorporated nucleotides that have escaped the proofreading activity of DNA polymerases, recognizing nonmismatched DNA adducts, and triggering a DNA damage response. In an attempt to determine whether MMR regulates replication progression in cells expressing an ultramutable DNA polymerase ɛ (Polɛ), carrying a proline-to-arginine substitution at amino acid 286 (Polɛ-P286R), we identified an unusual MMR function in response to hydroxyurea (HU)-induced replication stress. Polɛ-P286R cells treated with hydroxyurea exhibit increased MRE11-catalyzed nascent strand degradation. This degradation by MRE11 depends on the mismatch recognition protein MutSα and its binding to stalled replication forks. Increased MutSα binding at replication forks is also associated with decreased loading of replication fork protection factors FANCD2 and BRCA1, suggesting blockage of these fork protection factors from loading to replication forks by MutSα. We find that the MutSα-dependent MRE11-catalyzed fork degradation induces DNA breaks and various chromosome abnormalities. Therefore, unlike the well-known MMR functions of ensuring replication fidelity, the newly identified MMR activity of promoting genome instability may also play a role in cancer avoidance by eliminating rogue cells.
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16
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Chansavang A, Rousseau B, Leulliot N, Masliah-Planchon J, Bièche I, Pasmant É, Hamzaoui N. [Missense pathogenic variants in the exonuclease domain of polymerases Polε and Polδ in cancer: The risk of infidelity]. Med Sci (Paris) 2022; 38:763-765. [PMID: 36219073 DOI: 10.1051/medsci/2022118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Albain Chansavang
- Fédération de génétique et médecine génomique, hôpital Cochin, AP-HP, Centre-Université Paris Cité, Paris, France - Institut Cochin, Inserm U1016, CNRS UMR8104, université Paris Cité, CARPEM, Paris, France
| | - Benoit Rousseau
- Department of medicine, Division of solid tumor oncology, Memorial Sloan Kettering Cancer Center, New York, États-Unis
| | | | | | - Ivan Bièche
- Institut Cochin, Inserm U1016, CNRS UMR8104, université Paris Cité, CARPEM, Paris, France - Service de génétique, Institut Curie, Paris, France
| | - Éric Pasmant
- Fédération de génétique et médecine génomique, hôpital Cochin, AP-HP, Centre-Université Paris Cité, Paris, France - Institut Cochin, Inserm U1016, CNRS UMR8104, université Paris Cité, CARPEM, Paris, France
| | - Nadim Hamzaoui
- Fédération de génétique et médecine génomique, hôpital Cochin, AP-HP, Centre-Université Paris Cité, Paris, France - Institut Cochin, Inserm U1016, CNRS UMR8104, université Paris Cité, CARPEM, Paris, France
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17
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Zhou ZX, Kunkel TA. Extrinsic proofreading. DNA Repair (Amst) 2022; 117:103369. [PMID: 35850061 PMCID: PMC9561950 DOI: 10.1016/j.dnarep.2022.103369] [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: 03/27/2022] [Revised: 07/01/2022] [Accepted: 07/02/2022] [Indexed: 11/24/2022]
Abstract
The high fidelity of replication of the nuclear DNA genome in eukaryotes involves three processes. Correct rather than incorrect dNTPs are almost always incorporated by the three major replicases, DNA polymerases α, δ and ε. When an incorrect base is occasionally inserted, the latter Pols δ and ε also have a 3 ´ to 5 ´ exonuclease activity that can remove the mismatch to allow correct DNA synthesis to proceed. Lastly, rare mismatches that escape proofreading activity and are present in newly replicated DNA can be removed by DNA mismatch repair. In this review, we consider evidence supporting the hypothesis that the second mechanism, proofreading, can operate in two different ways. Primer terminal mismatches made by either Pol δ or Pol ε can be 'intrinsically' proofread. This mechanism occurs by direct transfer of a misinserted base made at the polymerase active site to the exonuclease active site that is located a short distance away. Intrinsic proofreading allows mismatch excision without intervening enzyme dissociation. Alternatively, considerable evidence suggests that mismatches made by any of the three replicases can also be proofread by 'extrinsic' proofreading by Pol δ. Extrinsic proofreading occurs when a mismatch made by any of the three replicases is initially abandoned, thereby allowing the exonuclease active site of Pol δ to bind directly to and remove the mismatch before replication continues. Here we review the evidence that extrinsic proofreading significantly enhances the fidelity of nuclear DNA replication, and we then briefly consider the implications of this process for evolution and disease.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA
| | - Thomas A Kunkel
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
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18
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Casas-Delucchi CS, Daza-Martin M, Williams SL, Coster G. The mechanism of replication stalling and recovery within repetitive DNA. Nat Commun 2022; 13:3953. [PMID: 35853874 PMCID: PMC9296464 DOI: 10.1038/s41467-022-31657-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 06/27/2022] [Indexed: 11/09/2022] Open
Abstract
Accurate chromosomal DNA replication is essential to maintain genomic stability. Genetic evidence suggests that certain repetitive sequences impair replication, yet the underlying mechanism is poorly defined. Replication could be directly inhibited by the DNA template or indirectly, for example by DNA-bound proteins. Here, we reconstitute replication of mono-, di- and trinucleotide repeats in vitro using eukaryotic replisomes assembled from purified proteins. We find that structure-prone repeats are sufficient to impair replication. Whilst template unwinding is unaffected, leading strand synthesis is inhibited, leading to fork uncoupling. Synthesis through hairpin-forming repeats is rescued by replisome-intrinsic mechanisms, whereas synthesis of quadruplex-forming repeats requires an extrinsic accessory helicase. DNA-induced fork stalling is mechanistically similar to that induced by leading strand DNA lesions, highlighting structure-prone repeats as an important potential source of replication stress. Thus, we propose that our understanding of the cellular response to replication stress may also be applied to DNA-induced replication stalling.
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Affiliation(s)
- Corella S Casas-Delucchi
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Manuel Daza-Martin
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Sophie L Williams
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Gideon Coster
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK.
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19
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Barbari SR, Beach AK, Markgren JG, Parkash V, Moore EA, Johansson E, Shcherbakova PV. Enhanced polymerase activity permits efficient synthesis by cancer-associated DNA polymerase ϵ variants at low dNTP levels. Nucleic Acids Res 2022; 50:8023-8040. [PMID: 35822874 PMCID: PMC9371911 DOI: 10.1093/nar/gkac602] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/13/2022] [Accepted: 06/29/2022] [Indexed: 11/28/2022] Open
Abstract
Amino acid substitutions in the exonuclease domain of DNA polymerase ϵ (Polϵ) cause ultramutated tumors. Studies in model organisms suggested pathogenic mechanisms distinct from a simple loss of exonuclease. These mechanisms remain unclear for most recurrent Polϵ mutations. Particularly, the highly prevalent V411L variant remained a long-standing puzzle with no detectable mutator effect in yeast despite the unequivocal association with ultramutation in cancers. Using purified four-subunit yeast Polϵ, we assessed the consequences of substitutions mimicking human V411L, S459F, F367S, L424V and D275V. While the effects on exonuclease activity vary widely, all common cancer-associated variants have increased DNA polymerase activity. Notably, the analog of Polϵ-V411L is among the strongest polymerases, and structural analysis suggests defective polymerase-to-exonuclease site switching. We further show that the V411L analog produces a robust mutator phenotype in strains that lack mismatch repair, indicating a high rate of replication errors. Lastly, unlike wild-type and exonuclease-dead Polϵ, hyperactive variants efficiently synthesize DNA at low dNTP concentrations. We propose that this characteristic could promote cancer cell survival and preferential participation of mutator polymerases in replication during metabolic stress. Our results support the notion that polymerase fitness, rather than low fidelity alone, is an important determinant of variant pathogenicity.
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Affiliation(s)
- Stephanie R Barbari
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Annette K Beach
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Joel G Markgren
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Vimal Parkash
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Elizabeth A Moore
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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20
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Baris Y, Taylor MRG, Aria V, Yeeles JTP. Fast and efficient DNA replication with purified human proteins. Nature 2022; 606:204-210. [PMID: 35585232 PMCID: PMC7613936 DOI: 10.1038/s41586-022-04759-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/13/2022] [Indexed: 12/16/2022]
Abstract
Chromosome replication is performed by a complex and intricate ensemble of proteins termed the replisome, where the DNA polymerases Polδ and Polε, DNA polymerase α-primase (Polα) and accessory proteins including AND-1, CLASPIN and TIMELESS-TIPIN (respectively known as Ctf4, Mrc1 and Tof1-Csm3 in Saccharomyces cerevisiae) are organized around the CDC45-MCM-GINS (CMG) replicative helicase1-7. Because a functional human replisome has not been reconstituted from purified proteins, how these factors contribute to human DNA replication and whether additional proteins are required for optimal DNA synthesis are poorly understood. Here we report the biochemical reconstitution of human replisomes that perform fast and efficient DNA replication using 11 purified human replication factors made from 43 polypeptides. Polε, but not Polδ, is crucial for optimal leading-strand synthesis. Unexpectedly, Polε-mediated leading-strand replication is highly dependent on the sliding-clamp processivity factor PCNA and the alternative clamp loader complex CTF18-RFC. We show how CLASPIN and TIMELESS-TIPIN contribute to replisome progression and demonstrate that, in contrast to the budding yeast replisome8, AND-1 directly augments leading-strand replication. Moreover, although AND-1 binds to Polα9,10, the interaction is dispensable for lagging-strand replication, indicating that Polα is functionally recruited via an AND-1-independent mechanism for priming in the human replisome. Collectively, our work reveals how the human replisome achieves fast and efficient leading-strand and lagging-strand DNA replication, and provides a powerful system for future studies of the human replisome and its interactions with other DNA metabolic processes.
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21
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Polymerase Epsilon-Associated Ultramutagenesis in Cancer. Cancers (Basel) 2022; 14:cancers14061467. [PMID: 35326618 PMCID: PMC8946778 DOI: 10.3390/cancers14061467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 01/27/2023] Open
Abstract
With advances in next generation sequencing (NGS) technologies, efforts have been made to develop personalized medicine, targeting the specific genetic makeup of an individual. Somatic or germline DNA Polymerase epsilon (PolE) mutations cause ultramutated (>100 mutations/Mb) cancer. In contrast to mismatch repair-deficient hypermutated (>10 mutations/Mb) cancer, PolE-associated cancer is primarily microsatellite stable (MSS) In this article, we provide a comprehensive review of this PolE-associated ultramutated tumor. We describe its molecular characteristics, including the mutation sites and mutation signature of this type of tumor and the mechanism of its ultramutagenesis. We discuss its good clinical prognosis and elucidate the mechanism for enhanced immunogenicity with a high tumor mutation burden, increased neoantigen load, and enriched tumor-infiltrating lymphocytes. We also provide the rationale for immune checkpoint inhibitors in PolE-mutated tumors.
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22
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Park VS, Sun MJS, Frey WD, Williams LG, Hodel KP, Strauss JD, Wellens SJ, Jackson JG, Pursell ZF. Mouse model and human patient data reveal critical roles for Pten and p53 in suppressing POLE mutant tumor development. NAR Cancer 2022; 4:zcac004. [PMID: 35252866 PMCID: PMC8892059 DOI: 10.1093/narcan/zcac004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/17/2022] [Accepted: 02/17/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in the exonuclease domain of POLE are associated with tumors harboring very high mutation burdens. The mechanisms linking this significant mutation accumulation and tumor development remain poorly understood. Pole+/P286R;Trp53+/– mice showed accelerated cancer mortality compared to Pole+/P286R;Trp53+/+ mice. Cells from Pole+/P286R mice showed increased p53 activation, and subsequent loss of p53 permitted rapid growth, implicating canonical p53 loss of heterozygosity in POLE mutant tumor growth. However, p53 status had no effect on tumor mutation burden or single base substitution signatures in POLE mutant tumors from mice or humans. Pten has important roles in maintaining genome stability. We find that PTEN mutations are highly enriched in human POLE mutant tumors, including many in POLE signature contexts. One such signature mutation, PTEN-F341V, was previously shown in a mouse model to specifically decrease nuclear Pten and lead to increased DNA damage. We found tumors in Pole+/P286R mice that spontaneously acquired PtenF341V mutations and were associated with significantly reduced nuclear Pten and elevated DNA damage. Re-analysis of human TCGA (The Cancer Genome Atlas) data showed that all PTEN-F341V mutations occurred in tumors with mutations in POLE. Taken together with recent published work, our results support the idea that development of POLE mutant tumors may involve disabling surveillance of nuclear DNA damage in addition to POLE-mediated hypermutagenesis.
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Affiliation(s)
- Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Meijuan J S Sun
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Wesley D Frey
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Leonard G Williams
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Juliet D Strauss
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Sydney J Wellens
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - James G Jackson
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
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23
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Abstract
DNA repair and DNA damage signaling pathways are critical for the maintenance of genomic stability. Defects of DNA repair and damage signaling contribute to tumorigenesis, but also render cancer cells vulnerable to DNA damage and reliant on remaining repair and signaling activities. Here, we review the major classes of DNA repair and damage signaling defects in cancer, the genomic instability that they give rise to, and therapeutic strategies to exploit the resulting vulnerabilities. Furthermore, we discuss the impacts of DNA repair defects on both targeted therapy and immunotherapy, and highlight emerging principles for targeting DNA repair defects in cancer therapy.
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Affiliation(s)
- Jessica L Hopkins
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.,Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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24
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Garmezy B, Gheeya J, Lin HY, Huang Y, Kim T, Jiang X, Thein KZ, Pilié PG, Zeineddine F, Wang W, Shaw KR, Rodon J, Shen JP, Yuan Y, Meric-Bernstam F, Chen K, Yap TA. Clinical and Molecular Characterization of POLE Mutations as Predictive Biomarkers of Response to Immune Checkpoint Inhibitors in Advanced Cancers. JCO Precis Oncol 2022; 6:e2100267. [PMID: 35108036 PMCID: PMC8820927 DOI: 10.1200/po.21.00267] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/16/2021] [Accepted: 12/28/2021] [Indexed: 12/12/2022] Open
Abstract
PURPOSE DNA polymerase epsilon is critical to DNA proofreading and replication. Mutations in POLE have been associated with hypermutated tumors and antitumor response to immune checkpoint inhibitor (ICI) therapy. We present a clinicopathologic analysis of patients with advanced cancers harboring POLE mutations, the pattern of co-occurring mutations, and their response to ICI therapy within the context of mutation pathogenicity. METHODS We conducted a retrospective analysis of next-generation sequencing data at MD Anderson Cancer Center to identify patient tumors with POLE mutations and their co-occurring mutations. The pathogenicity of each mutation was annotated using InterVar and ClinVar. Differences in therapeutic response to ICI, survival, and co-occurring mutations were reported by POLE pathogenicity status. RESULTS Four hundred fifty-eight patient tumors with POLE mutations were identified from 14,229 next-generation sequencing reports; 15.0% of POLE mutations were pathogenic, 15.9% benign, and 69.1% variant of unknown significance. Eighty-two patients received either programmed death 1 or programmed death ligand-1 inhibitors as monotherapy or in combination with cytotoxic T-cell lymphocyte-4 inhibitors. Patients with pathogenic POLE mutations had improved clinical benefit rate (82.4% v 30.0%; P = .013), median progression-free survival (15.1 v 2.2 months; P < .001), overall survival (29.5 v 6.8 months; P < .001), and longer treatment duration (median 15.5 v 2.5 months; P < .001) compared to those with benign variants. Progression-free survival and overall survival remained superior when adjusting for number of co-occurring mutations (≥ 10 v < 10) and/or microsatellite instability status (proficient mismatch repair v deficient mismatch repair). The number of comutations was not associated with response to ICI (clinical benefit v progressive disease: median 13 v 11 comutations; P = .18). CONCLUSION Pathogenic POLE mutations were associated with clinical benefit to ICI therapy. Further studies are warranted to validate POLE mutation as a predictive biomarker of ICI therapy.
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Affiliation(s)
- Benjamin Garmezy
- Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Jinesh Gheeya
- The University of Texas Health Science Center at Houston, Houston, TX
| | - Heather Y. Lin
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Yuefan Huang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Taebeom Kim
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Xianli Jiang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Kyaw Z. Thein
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Patrick G. Pilié
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Fadl Zeineddine
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Wanlin Wang
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Kenna R. Shaw
- Khalifa Institute for Personalized Cancer Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Jordi Rodon
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX
| | - John Paul Shen
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Ying Yuan
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Funda Meric-Bernstam
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX
- Khalifa Institute for Personalized Cancer Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Ken Chen
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Timothy A. Yap
- Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston, TX
- Khalifa Institute for Personalized Cancer Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX
- The Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, TX
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25
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Probing altered enzyme activity in the biochemical characterization of cancer. Biosci Rep 2022; 42:230680. [PMID: 35048115 PMCID: PMC8819661 DOI: 10.1042/bsr20212002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/10/2022] [Accepted: 01/19/2022] [Indexed: 11/30/2022] Open
Abstract
Enzymes have evolved to catalyze their precise reactions at the necessary rates, locations, and time to facilitate our development, to respond to a variety of insults and challenges, and to maintain a healthy, balanced state. Enzymes achieve this extraordinary feat through their unique kinetic parameters, myriad regulatory strategies, and their sensitivity to their surroundings, including substrate concentration and pH. The Cancer Genome Atlas (TCGA) highlights the extraordinary number of ways in which the finely tuned activities of enzymes can be disrupted, contributing to cancer development and progression often due to somatic and/or inherited genetic alterations. Rather than being limited to the domain of enzymologists, kinetic constants such as kcat, Km, and kcat/Km are highly informative parameters that can impact a cancer patient in tangible ways—these parameters can be used to sort tumor driver mutations from passenger mutations, to establish the pathways that cancer cells rely on to drive patients’ tumors, to evaluate the selectivity and efficacy of anti-cancer drugs, to identify mechanisms of resistance to treatment, and more. In this review, we will discuss how changes in enzyme activity, primarily through somatic mutation, can lead to altered kinetic parameters, new activities, or changes in conformation and oligomerization. We will also address how changes in the tumor microenvironment can affect enzymatic activity, and briefly describe how enzymology, when combined with additional powerful tools, and can provide us with tremendous insight into the chemical and molecular mechanisms of cancer.
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26
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Dahl JM, Thomas N, Tracy MA, Hearn BL, Perera L, Kennedy SR, Herr AJ, Kunkel TA. Probing the mechanisms of two exonuclease domain mutators of DNA polymerase ϵ. Nucleic Acids Res 2022; 50:962-974. [PMID: 35037018 DOI: 10.1093/nar/gkab1255] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/21/2021] [Accepted: 12/08/2021] [Indexed: 11/15/2022] Open
Abstract
We report the properties of two mutations in the exonuclease domain of the Saccharomyces cerevisiae DNA polymerase ϵ. One, pol2-Y473F, increases the mutation rate by about 20-fold, similar to the catalytically dead pol2-D290A/E290A mutant. The other, pol2-N378K, is a stronger mutator. Both retain the ability to excise a nucleotide from double-stranded DNA, but with impaired activity. pol2-Y473F degrades DNA poorly, while pol2-N378K degrades single-stranded DNA at an elevated rate relative to double-stranded DNA. These data suggest that pol2-Y473F reduces the capacity of the enzyme to perform catalysis in the exonuclease active site, while pol2-N378K impairs partitioning to the exonuclease active site. Relative to wild-type Pol ϵ, both variants decrease the dNTP concentration required to elicit a switch between proofreading and polymerization by more than an order of magnitude. While neither mutation appears to alter the sequence specificity of polymerization, the N378K mutation stimulates polymerase activity, increasing the probability of incorporation and extension of a mismatch. Considered together, these data indicate that impairing the primer strand transfer pathway required for proofreading increases the probability of common mutations by Pol ϵ, elucidating the association of homologous mutations in human DNA polymerase ϵ with cancer.
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Affiliation(s)
- Joseph M Dahl
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, DHHS, Research Triangle Park, NC 27709, USA
| | - Natalie Thomas
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, DHHS, Research Triangle Park, NC 27709, USA
| | - Maxwell A Tracy
- Department of Laboratory Medicine and Pathology, UW Medicine, Seattle, WA 98195, USA
| | - Brady L Hearn
- Department of Laboratory Medicine and Pathology, UW Medicine, Seattle, WA 98195, USA
| | - Lalith Perera
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, DHHS, Research Triangle Park, NC 27709, USA
| | - Scott R Kennedy
- Department of Laboratory Medicine and Pathology, UW Medicine, Seattle, WA 98195, USA
| | - Alan J Herr
- Department of Laboratory Medicine and Pathology, UW Medicine, Seattle, WA 98195, USA
| | - Thomas A Kunkel
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, DHHS, Research Triangle Park, NC 27709, USA
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27
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Sehested A, Meade J, Scheie D, Østrup O, Bertelsen B, Misiakou MA, Sarosiek T, Kessler E, Melchior LC, Munch-Petersen HF, Pai RK, Schmuth M, Gottschling H, Zschocke J, Gallon R, Wimmer K. Constitutional POLE variants causing a phenotype reminiscent of constitutional mismatch repair deficiency. Hum Mutat 2022; 43:85-96. [PMID: 34816535 DOI: 10.1002/humu.24299] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 12/20/2022]
Abstract
Heterozygous POLE or POLD1 germline pathogenic variants (PVs) cause polymerase proofreading associated polyposis (PPAP), a constitutional polymerase proofreading deficiency that typically presents with colorectal adenomas and carcinomas in adulthood. Constitutional mismatch-repair deficiency (CMMRD), caused by germline bi-allelic PVs affecting one of four MMR genes, results in a high propensity for the hematological, brain, intestinal tract, and other malignancies in childhood. Nonmalignant clinical features, such as skin pigmentation alterations, are found in nearly all CMMRD patients and are important diagnostic markers. Here, we excluded CMMRD in three cancer patients with highly suspect clinical phenotypes but identified in each a constitutional heterozygous POLE PV. These, and two additional POLE PVs identified in published CMMRD-like patients, have not previously been reported as germline PVs despite all being well-known somatic mutations in hyper-mutated tumors. Together, these five cases show that specific POLE PVs may have a stronger "mutator" effect than known PPAP-associated POLE PVs and may cause a CMMRD-like phenotype distinct from PPAP. The common underlying mechanism, that is, a constitutional replication error repair defect, and a similar tumor spectrum provide a good rationale for monitoring these patients with a severe constitutional polymerase proofreading deficiency according to protocols proposed for CMMRD.
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Affiliation(s)
- Astrid Sehested
- Department of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Julia Meade
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - David Scheie
- Department of Pathology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Olga Østrup
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Birgitte Bertelsen
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Maria Anna Misiakou
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Elena Kessler
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Linea C Melchior
- Department of Pathology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Reetesh K Pai
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Matthias Schmuth
- Department of Dermatology, Venereology and Allergy, Medical University of Innsbruck, Innsbruck, Austria
| | - Hendrik Gottschling
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Zschocke
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Richard Gallon
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Katharina Wimmer
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
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28
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Ottini A, Sepe P, Beninato T, Claps M, Guadalupi V, Verzoni E, Giannatempo P, Baciarello G, de Braud F, Procopio G. Biomarker-driven immunotherapy for precision medicine in prostate cancer. Per Med 2021; 19:51-66. [PMID: 34873959 DOI: 10.2217/pme-2021-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although immunotherapy has recently revolutionized standard of care in different cancer types, prostate cancer has generally failed to show dramatic responses to immune checkpoint inhibitors. As in other tumors, the goal in prostate cancer is now to target treatments more precisely on patient's individual characteristics through precision medicine. Defects in mismatch repair, mutations in the exonuclease domain of the DNA polymerase epsilon (POLE), high tumor mutational burden and the presence of biallelic loss of CDK12 among others, are predictive biomarkers of response to immunotherapy. In the present review, we summarize the evolving landscape of immunotherapy in prostate cancer, including precision approaches and strategies to define classes of responsive patients and scale up resistance to immune checkpoint inhibitors.
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Affiliation(s)
- Arianna Ottini
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Pierangela Sepe
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Teresa Beninato
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Mélanie Claps
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Valentina Guadalupi
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Elena Verzoni
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Patrizia Giannatempo
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Giulia Baciarello
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Filippo de Braud
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Giuseppe Procopio
- Department of Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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29
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Zhou ZX, Lujan SA, Burkholder AB, St. Charles J, Dahl J, Farrell CE, Williams JS, Kunkel TA. How asymmetric DNA replication achieves symmetrical fidelity. Nat Struct Mol Biol 2021; 28:1020-1028. [PMID: 34887558 PMCID: PMC8815454 DOI: 10.1038/s41594-021-00691-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/22/2021] [Indexed: 11/09/2022]
Abstract
Accurate DNA replication of an undamaged template depends on polymerase selectivity for matched nucleotides, exonucleolytic proofreading of mismatches, and removal of remaining mismatches via DNA mismatch repair (MMR). DNA polymerases (Pols) δ and ε have 3'-5' exonucleases into which mismatches are partitioned for excision in cis (intrinsic proofreading). Here we provide strong evidence that Pol δ can extrinsically proofread mismatches made by itself and those made by Pol ε, independently of both Pol δ's polymerization activity and MMR. Extrinsic proofreading across the genome is remarkably efficient. We report, with unprecedented accuracy, in vivo contributions of nucleotide selectivity, proofreading, and MMR to the fidelity of DNA replication in Saccharomyces cerevisiae. We show that extrinsic proofreading by Pol δ improves and balances the fidelity of the two DNA strands. Together, we depict a comprehensive picture of how nucleotide selectivity, proofreading, and MMR cooperate to achieve high and symmetrical fidelity on the two strands.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Scott A. Lujan
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Adam B. Burkholder
- Integrative Bioinformatics Support Group, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Jordan St. Charles
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Joseph Dahl
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Corinne E. Farrell
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Jessica S. Williams
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Thomas A. Kunkel
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
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30
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Genomic instability as a major mechanism for acquired resistance to EGFR tyrosine kinase inhibitors in cancer. Protein Cell 2021; 13:82-89. [PMID: 34319535 PMCID: PMC8783936 DOI: 10.1007/s13238-021-00855-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2021] [Indexed: 11/17/2022] Open
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31
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Soriano I, Vazquez E, De Leon N, Bertrand S, Heitzer E, Toumazou S, Bo Z, Palles C, Pai CC, Humphrey TC, Tomlinson I, Cotterill S, Kearsey SE. Expression of the cancer-associated DNA polymerase ε P286R in fission yeast leads to translesion synthesis polymerase dependent hypermutation and defective DNA replication. PLoS Genet 2021; 17:e1009526. [PMID: 34228709 PMCID: PMC8284607 DOI: 10.1371/journal.pgen.1009526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/16/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
Somatic and germline mutations in the proofreading domain of the replicative DNA polymerase ε (POLE-exonuclease domain mutations, POLE-EDMs) are frequently found in colorectal and endometrial cancers and, occasionally, in other tumours. POLE-associated cancers typically display hypermutation, and a unique mutational signature, with a predominance of C > A transversions in the context TCT and C > T transitions in the context TCG. To understand better the contribution of hypermutagenesis to tumour development, we have modelled the most recurrent POLE-EDM (POLE-P286R) in Schizosaccharomyces pombe. Whole-genome sequencing analysis revealed that the corresponding pol2-P287R allele also has a strong mutator effect in vivo, with a high frequency of base substitutions and relatively few indel mutations. The mutations are equally distributed across different genomic regions, but in the immediate vicinity there is an asymmetry in AT frequency. The most abundant base-pair changes are TCT > TAT transversions and, in contrast to human mutations, TCG > TTG transitions are not elevated, likely due to the absence of cytosine methylation in fission yeast. The pol2-P287R variant has an increased sensitivity to elevated dNTP levels and DNA damaging agents, and shows reduced viability on depletion of the Pfh1 helicase. In addition, S phase is aberrant and RPA foci are elevated, suggestive of ssDNA or DNA damage, and the pol2-P287R mutation is synthetically lethal with rad3 inactivation, indicative of checkpoint activation. Significantly, deletion of genes encoding some translesion synthesis polymerases, most notably Pol κ, partially suppresses pol2-P287R hypermutation, indicating that polymerase switching contributes to this phenotype.
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Affiliation(s)
- Ignacio Soriano
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Enrique Vazquez
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Nagore De Leon
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | | | - Ellen Heitzer
- Institute of Human Genetics, Diagnostic & Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria
| | - Sophia Toumazou
- ZRAB, University of Oxford, Oxford, United Kingdom
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Zhihan Bo
- ZRAB, University of Oxford, Oxford, United Kingdom
| | - Claire Palles
- Gastrointestinal Cancer Genetics Laboratory, Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Chen-Chun Pai
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Timothy C. Humphrey
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Ian Tomlinson
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Sue Cotterill
- St. George’s, University of London, Cranmer Terrace, Tooting, London, United Kingdom
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32
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Checkpoint-mediated DNA polymerase ε exonuclease activity curbing counteracts resection-driven fork collapse. Mol Cell 2021; 81:2778-2792.e4. [PMID: 33932350 PMCID: PMC7612761 DOI: 10.1016/j.molcel.2021.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 02/01/2023]
Abstract
DNA polymerase ε (Polε) carries out high-fidelity leading strand synthesis owing to its exonuclease activity. Polε polymerase and exonuclease activities are balanced, because of partitioning of nascent DNA strands between catalytic sites, so that net resection occurs when synthesis is impaired. In vivo, DNA synthesis stalling activates replication checkpoint kinases, which act to preserve the functional integrity of replication forks. We show that stalled Polε drives nascent strand resection causing fork functional collapse, averted via checkpoint-dependent phosphorylation. Polε catalytic subunit Pol2 is phosphorylated on serine 430, influencing partitioning between polymerase and exonuclease active sites. A phosphormimetic S430D change reduces exonucleolysis in vitro and counteracts fork collapse. Conversely, non-phosphorylatable pol2-S430A expression causes resection-driven stressed fork defects. Our findings reveal that checkpoint kinases switch Polε to an exonuclease-safe mode preventing nascent strand resection and stabilizing stalled replication forks. Elective partitioning suppression has implications for the diverse Polε roles in genome integrity maintenance.
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33
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Herzog M, Alonso-Perez E, Salguero I, Warringer J, Adams D, Jackson SP, Puddu F. Mutagenic mechanisms of cancer-associated DNA polymerase ϵ alleles. Nucleic Acids Res 2021; 49:3919-3931. [PMID: 33764464 PMCID: PMC8053093 DOI: 10.1093/nar/gkab160] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/03/2021] [Indexed: 01/08/2023] Open
Abstract
A single amino acid residue change in the exonuclease domain of human DNA polymerase ϵ, P286R, is associated with the development of colorectal cancers, and has been shown to impart a mutator phenotype. The corresponding Pol ϵ allele in the yeast Saccharomyces cerevisiae (pol2-P301R), was found to drive greater mutagenesis than an entirely exonuclease-deficient Pol ϵ (pol2-4), an unexpected phenotype of ultra-mutagenesis. By studying the impact on mutation frequency, type, replication-strand bias, and sequence context, we show that ultra-mutagenesis is commonly observed in yeast cells carrying a range of cancer-associated Pol ϵ exonuclease domain alleles. Similarities between mutations generated by these alleles and those generated in pol2-4 cells indicate a shared mechanism of mutagenesis that yields a mutation pattern similar to cancer Signature 14. Comparison of POL2 ultra-mutator with pol2-M644G, a mutant in the polymerase domain decreasing Pol ϵ fidelity, revealed unexpected analogies in the sequence context and strand bias of mutations. Analysis of mutational patterns unique to exonuclease domain mutant cells suggests that backtracking of the polymerase, when the mismatched primer end cannot be accommodated in the proofreading domain, results in the observed insertions and T>A mutations in specific sequence contexts.
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Affiliation(s)
- Mareike Herzog
- The Wellcome/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
- The Wellcome Sanger Institute, Hinxton CB10 1HH, UK
| | - Elisa Alonso-Perez
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90, Göteborg, Sweden
| | - Israel Salguero
- The Wellcome/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90, Göteborg, Sweden
| | | | - Stephen P Jackson
- The Wellcome/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Fabio Puddu
- The Wellcome/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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34
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Stepchenkova EI, Zhuk AS, Cui J, Tarakhovskaya ER, Barbari SR, Shcherbakova PV, Polev DE, Fedorov R, Poliakov E, Rogozin IB, Lada AG, Pavlov YI. Compensation for the absence of the catalytically active half of DNA polymerase ε in yeast by positively selected mutations in CDC28. Genetics 2021; 218:6222163. [PMID: 33844024 DOI: 10.1093/genetics/iyab060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 04/02/2021] [Indexed: 11/14/2022] Open
Abstract
Current eukaryotic replication models postulate that leading and lagging DNA strands are replicated predominantly by dedicated DNA polymerases. The catalytic subunit of the leading strand DNA polymerase ε, Pol2, consists of two halves made of two different ancestral B-family DNA polymerases. Counterintuitively, the catalytically active N-terminal half is dispensable, while the inactive C-terminal part is required for viability. Despite extensive studies of yeast Saccharomyces cerevisiae strains lacking the active N-terminal half, it is still unclear how these strains survive and recover. We designed a robust method for constructing mutants with only the C-terminal part of Pol2. Strains without the active polymerase part show severe growth defects, sensitivity to replication inhibitors, chromosomal instability, and elevated spontaneous mutagenesis. Intriguingly, the slow-growing mutant strains rapidly accumulate fast-growing clones. Analysis of genomic DNA sequences of these clones revealed that the adaptation to the loss of the catalytic N-terminal part of Pol2 occurs by a positive selection of mutants with improved growth. Elevated mutation rates help generate sufficient numbers of these variants. Single nucleotide changes in the cell cycle-dependent kinase gene, CDC28, improve the growth of strains lacking the N-terminal part of Pol2, and rescue their sensitivity to replication inhibitors and, in parallel, lower mutation rates. Our study predicts that changes in mammalian homologs of cyclin-dependent kinases may contribute to cellular responses to the leading strand polymerase defects.
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Affiliation(s)
- Elena I Stepchenkova
- Laboratory of Mutagenesis and Genetic Toxicology, Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, Saint-Petersburg 199034, Russia.,Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg 199034, Russia.,Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Anna S Zhuk
- ITMO University, Saint-Petersburg 191002, Russia
| | - Jian Cui
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Elena R Tarakhovskaya
- Laboratory of Mutagenesis and Genetic Toxicology, Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, Saint-Petersburg 199034, Russia.,Department of Plant Physiology and Biochemistry, Saint-Petersburg State University, Saint-Petersburg 199034, Russia
| | - Stephanie R Barbari
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Dmitrii E Polev
- Research Resource Center "Biobank," Research Park, Saint-Petersburg State University, Saint-Petersburg 198504, Russia
| | - Roman Fedorov
- Department of Mathematics, University of Pittsburgh, PA 15213, USA
| | - Eugenia Poliakov
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Artem G Lada
- Department of Microbiology and Molecular Genetics, University of California Davis, Davis, CA 92697, USA
| | - Youri I Pavlov
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg 199034, Russia.,Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Microbiology and Pathology, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Díaz-Gay M, Alexandrov LB. Unraveling the genomic landscape of colorectal cancer through mutational signatures. Adv Cancer Res 2021; 151:385-424. [PMID: 34148618 DOI: 10.1016/bs.acr.2021.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Colorectal cancer, along with most other cancer types, is driven by somatic mutations. Characteristic patterns of somatic mutations, known as mutational signatures, arise as a result of the activities of different mutational processes. Mutational signatures have diverse origins, including exogenous and endogenous sources. In the case of colorectal cancer, the analysis of mutational signatures has elucidated specific signatures for classically associated DNA repair deficiencies, namely mismatch repair (leading to microsatellite instability), base excision repair (due to MUTYH or NTHL1 mutations), and polymerase proofreading (due to POLE and POLD1 exonuclease domain mutations). Additional signatures also play a role in colorectal cancer, including those related to normal aging and those associated with gut microbiota, as well as a number of signatures with unknown etiologies. This chapter provides an overview of the current knowledge of mutational signatures, with a focus on colorectal cancer and on the recently reported signatures in physiologically normal and inflammatory bowel disease-affected somatic colon tissues.
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Affiliation(s)
- Marcos Díaz-Gay
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, United States; Department of Bioengineering, UC San Diego, La Jolla, CA, United States; Moores Cancer Center, UC San Diego, La Jolla, CA, United States
| | - Ludmil B Alexandrov
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, United States; Department of Bioengineering, UC San Diego, La Jolla, CA, United States; Moores Cancer Center, UC San Diego, La Jolla, CA, United States.
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Alvarado-Cruz I, Meas R, Paluri SLA, Carufe KEW, Khan M, Sweasy JB. The double-edged sword of cancer mutations: exploiting neoepitopes for the fight against cancer. Mutagenesis 2021; 35:69-78. [PMID: 31880305 DOI: 10.1093/mutage/gez049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Abstract
Defects in DNA repair have been linked to the accumulation of somatic mutations in tumours. These mutations can promote oncogenesis; however, recent developments have indicated that they may also lead to a targeted immune response against the tumour. This response is initiated by the development of new antigenic epitopes (neoepitopes) arising from mutations in protein-coding genes that are processed and then presented on the surface of tumour cells. These neoepitopes are unique to the tumour, thus enabling lymphocytes to launch an immune response against the cancer cells. Immunotherapies, such as checkpoint inhibitors (CPIs) and tumour-derived vaccines, have been shown to enhance the immunogenic response to cancers and have led to complete remission in some cancer patients. There are tumours that are not responsive to immunotherapy or conventional tumour therapeutics; therefore, there is a push for new treatments to combat these unresponsive cancers. Recently, combinatorial treatments have been developed to further utilise the immune system in the fight against cancer. These treatments have the potential to exploit the defects in DNA repair by inducing more DNA damage and mutations. This can potentially lead to the expression of high levels of neoepitopes on the surface of tumour cells that will stimulate an immunological response. Overall, exploiting DNA repair defects in tumours may provide an edge in this long fight against cancer.
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Affiliation(s)
| | - Rithy Meas
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | | | | | - Mohammed Khan
- Department of Cellular and Molecular Medicine, UA College of Medicine, Tucson, AZ, USA
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Chung J, Maruvka YE, Sudhaman S, Kelly J, Haradhvala NJ, Bianchi V, Edwards M, Forster VJ, Nunes NM, Galati MA, Komosa M, Deshmukh S, Cabric V, Davidson S, Zatzman M, Light N, Hayes R, Brunga L, Anderson ND, Ho B, Hodel KP, Siddaway R, Morrissy AS, Bowers DC, Larouche V, Bronsema A, Osborn M, Cole KA, Opocher E, Mason G, Thomas GA, George B, Ziegler DS, Lindhorst S, Vanan M, Yalon-Oren M, Reddy AT, Massimino M, Tomboc P, Van Damme A, Lossos A, Durno C, Aronson M, Morgenstern DA, Bouffet E, Huang A, Taylor MD, Villani A, Malkin D, Hawkins CE, Pursell ZF, Shlien A, Kunkel TA, Getz G, Tabori U. DNA Polymerase and Mismatch Repair Exert Distinct Microsatellite Instability Signatures in Normal and Malignant Human Cells. Cancer Discov 2020; 11:1176-1191. [PMID: 33355208 DOI: 10.1158/2159-8290.cd-20-0790] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/23/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022]
Abstract
Although replication repair deficiency, either by mismatch repair deficiency (MMRD) and/or loss of DNA polymerase proofreading, can cause hypermutation in cancer, microsatellite instability (MSI) is considered a hallmark of MMRD alone. By genome-wide analysis of tumors with germline and somatic deficiencies in replication repair, we reveal a novel association between loss of polymerase proofreading and MSI, especially when both components are lost. Analysis of indels in microsatellites (MS-indels) identified five distinct signatures (MS-sigs). MMRD MS-sigs are dominated by multibase losses, whereas mutant-polymerase MS-sigs contain primarily single-base gains. MS deletions in MMRD tumors depend on the original size of the MS and converge to a preferred length, providing mechanistic insight. Finally, we demonstrate that MS-sigs can be a powerful clinical tool for managing individuals with germline MMRD and replication repair-deficient cancers, as they can detect the replication repair deficiency in normal cells and predict their response to immunotherapy. SIGNIFICANCE: Exome- and genome-wide MSI analysis reveals novel signatures that are uniquely attributed to mismatch repair and DNA polymerase. This provides new mechanistic insight into MS maintenance and can be applied clinically for diagnosis of replication repair deficiency and immunotherapy response prediction.This article is highlighted in the In This Issue feature, p. 995.
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Affiliation(s)
- Jiil Chung
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yosef E Maruvka
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts
| | - Sumedha Sudhaman
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jacalyn Kelly
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nicholas J Haradhvala
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts.,Harvard Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts
| | - Vanessa Bianchi
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa Edwards
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Victoria J Forster
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nuno M Nunes
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa A Galati
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Martin Komosa
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shriya Deshmukh
- Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,The Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Vanja Cabric
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Scott Davidson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Matthew Zatzman
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Nicholas Light
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Reid Hayes
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ledia Brunga
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nathaniel D Anderson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ben Ho
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University of Medicine, New Orleans, Louisiana
| | - Robert Siddaway
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - A Sorana Morrissy
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Charbonneau Cancer Institute and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Daniel C Bowers
- Department of Pediatrics and Harold C. Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center, Dallas, Texas.,Pauline Allen Gill Center for Cancer and Blood Disorders, Children's Health, Dallas, Texas
| | - Valérie Larouche
- Department of Pediatrics, Centre Mere-enfant Soleil du CHU de Quebec, CRCHU de Quebec, Universite Laval, Quebec City, Quebec, Canada
| | - Annika Bronsema
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Osborn
- Department of Haematology and Oncology, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Kristina A Cole
- Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Enrico Opocher
- Pediatric Oncology and Hematology, Azienda Ospedaliera-Universita' degli Studi di Padova, Padova, Italy
| | - Gary Mason
- Department of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania
| | - Gregory A Thomas
- Division of Pediatric Hematology-Oncology, Oregon Health and Science University, Portland, Oregon
| | - Ben George
- Division of Hematology and Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - David S Ziegler
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, New South Wales, Australia.,Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales, Australia
| | - Scott Lindhorst
- Neuro-Oncology, Department of Neurosurgery, and Department of Medicine, Division of Hematology/Medical Oncology, Medical University of South Carolina Charleston, South Carolina
| | - Magimairajan Vanan
- Department of Pediatric Hematology-Oncology, Cancer Care Manitoba; Research Institute in Oncology and Hematology (RIOH), University of Manitoba, Winnipeg, Manitoba, Canada
| | - Michal Yalon-Oren
- Pediatric Hemato-Oncology, Edmond and Lilly Safra Children's Hospital and Cancer Research Center, Sheba Medical Center, Tel Hashomer Affiliated to the Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Alyssa T Reddy
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Maura Massimino
- Pediatric Unit, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), Milano, Italy
| | - Patrick Tomboc
- Department of Pediatrics Section of Hematology-Oncology, WVU Medicine Children's, Morgantown, West Virginia
| | - An Van Damme
- Division of Hematology and Oncology, Department of Pediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Alexander Lossos
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Carol Durno
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada.,Division of Gastroenterology, Hepatology and Nutrition, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melyssa Aronson
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Daniel A Morgenstern
- Department of Paediatrics, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Eric Bouffet
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Annie Huang
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael D Taylor
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anita Villani
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - David Malkin
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cynthia E Hawkins
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University of Medicine, New Orleans, Louisiana
| | - Adam Shlien
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Thomas A Kunkel
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Durham, North Carolina
| | - Gad Getz
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts. .,Broad Institute of Harvard and MIT, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts
| | - Uri Tabori
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada. .,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Galati MA, Hodel KP, Gams MS, Sudhaman S, Bridge T, Zahurancik WJ, Ungerleider NA, Park VS, Ercan AB, Joksimovic L, Siddiqui I, Siddaway R, Edwards M, de Borja R, Elshaer D, Chung J, Forster VJ, Nunes NM, Aronson M, Wang X, Ramdas J, Seeley A, Sarosiek T, Dunn GP, Byrd JN, Mordechai O, Durno C, Martin A, Shlien A, Bouffet E, Suo Z, Jackson JG, Hawkins CE, Guidos CJ, Pursell ZF, Tabori U. Cancers from Novel Pole-Mutant Mouse Models Provide Insights into Polymerase-Mediated Hypermutagenesis and Immune Checkpoint Blockade. Cancer Res 2020; 80:5606-5618. [PMID: 32938641 PMCID: PMC8218238 DOI: 10.1158/0008-5472.can-20-0624] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/25/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022]
Abstract
POLE mutations are a major cause of hypermutant cancers, yet questions remain regarding mechanisms of tumorigenesis, genotype-phenotype correlation, and therapeutic considerations. In this study, we establish mouse models harboring cancer-associated POLE mutations P286R and S459F, which cause rapid albeit distinct time to cancer initiation in vivo, independent of their exonuclease activity. Mouse and human correlates enabled novel stratification of POLE mutations into three groups based on clinical phenotype and mutagenicity. Cancers driven by these mutations displayed striking resemblance to the human ultrahypermutation and specific signatures. Furthermore, Pole-driven cancers exhibited a continuous and stochastic mutagenesis mechanism, resulting in intertumoral and intratumoral heterogeneity. Checkpoint blockade did not prevent Pole lymphomas, but rather likely promoted lymphomagenesis as observed in humans. These observations provide insights into the carcinogenesis of POLE-driven tumors and valuable information for genetic counseling, surveillance, and immunotherapy for patients. SIGNIFICANCE: Two mouse models of polymerase exonuclease deficiency shed light on mechanisms of mutation accumulation and considerations for immunotherapy.See related commentary by Wisdom and Kirsch p. 5459.
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Affiliation(s)
- Melissa A Galati
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Miki S Gams
- Program in Developmental and Stem Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Sumedha Sudhaman
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Taylor Bridge
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Walter J Zahurancik
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
| | - Nathan A Ungerleider
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Ayse B Ercan
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lazar Joksimovic
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Iram Siddiqui
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Robert Siddaway
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa Edwards
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Richard de Borja
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dana Elshaer
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jiil Chung
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Victoria J Forster
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nuno M Nunes
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melyssa Aronson
- The Familial Gastrointestinal Cancer Registry at the Zane Cohen Centre for Digestive Disease, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Xia Wang
- H Lee Moffitt Cancer Centre and Research Institute, Tampa, Florida
| | - Jagadeesh Ramdas
- Department of Pediatrics, Geisinger Medical Center, Danville, Pennsylvania
| | - Andrea Seeley
- Department of Pediatrics, Geisinger Medical Center, Danville, Pennsylvania
| | | | - Gavin P Dunn
- Department of Neurological Surgery, Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri
| | - Jonathan N Byrd
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Oz Mordechai
- Department of Pediatric Hematology Oncology, Rambam Health Care Campus, Haifa, Israel
| | - Carol Durno
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alberto Martin
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Adam Shlien
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Eric Bouffet
- Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zucai Suo
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
| | - James G Jackson
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Cynthia E Hawkins
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Cynthia J Guidos
- Program in Developmental and Stem Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Uri Tabori
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Pavlov YI, Zhuk AS, Stepchenkova EI. DNA Polymerases at the Eukaryotic Replication Fork Thirty Years after: Connection to Cancer. Cancers (Basel) 2020; 12:E3489. [PMID: 33255191 PMCID: PMC7760166 DOI: 10.3390/cancers12123489] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 12/13/2022] Open
Abstract
Recent studies on tumor genomes revealed that mutations in genes of replicative DNA polymerases cause a predisposition for cancer by increasing genome instability. The past 10 years have uncovered exciting details about the structure and function of replicative DNA polymerases and the replication fork organization. The principal idea of participation of different polymerases in specific transactions at the fork proposed by Morrison and coauthors 30 years ago and later named "division of labor," remains standing, with an amendment of the broader role of polymerase δ in the replication of both the lagging and leading DNA strands. However, cancer-associated mutations predominantly affect the catalytic subunit of polymerase ε that participates in leading strand DNA synthesis. We analyze how new findings in the DNA replication field help elucidate the polymerase variants' effects on cancer.
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Affiliation(s)
- Youri I. Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Genetics and Biotechnology, Saint-Petersburg State University, 199034 Saint Petersburg, Russia;
| | - Anna S. Zhuk
- International Laboratory of Computer Technologies, ITMO University, 197101 Saint Petersburg, Russia;
| | - Elena I. Stepchenkova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, 199034 Saint Petersburg, Russia;
- Laboratory of Mutagenesis and Genetic Toxicology, Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, 199034 Saint Petersburg, Russia
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40
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Bulock CR, Xing X, Shcherbakova PV. Mismatch repair and DNA polymerase δ proofreading prevent catastrophic accumulation of leading strand errors in cells expressing a cancer-associated DNA polymerase ϵ variant. Nucleic Acids Res 2020; 48:9124-9134. [PMID: 32756902 PMCID: PMC7498342 DOI: 10.1093/nar/gkaa633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/13/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022] Open
Abstract
Substitutions in the exonuclease domain of DNA polymerase ϵ cause ultramutated human tumors. Yeast and mouse mimics of the most common variant, P286R, produce mutator effects far exceeding the effect of Polϵ exonuclease deficiency. Yeast Polϵ-P301R has increased DNA polymerase activity, which could underlie its high mutagenicity. We aimed to understand the impact of this increased activity on the strand-specific role of Polϵ in DNA replication and the action of extrinsic correction systems that remove Polϵ errors. Using mutagenesis reporters spanning a well-defined replicon, we show that both exonuclease-deficient Polϵ (Polϵ-exo−) and Polϵ-P301R generate mutations in a strictly strand-specific manner, yet Polϵ-P301R is at least ten times more mutagenic than Polϵ-exo− at each location analyzed. Thus, the cancer variant remains a dedicated leading-strand polymerase with markedly low accuracy. We further show that P301R substitution is lethal in strains lacking Polδ proofreading or mismatch repair (MMR). Heterozygosity for pol2-P301R is compatible with either defect but causes strong synergistic increases in the mutation rate, indicating that Polϵ-P301R errors are corrected by Polδ proofreading and MMR. These data reveal the unexpected ease with which polymerase exchange occurs in vivo, allowing Polδ exonuclease to prevent catastrophic accumulation of Polϵ-P301R-generated errors on the leading strand.
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Affiliation(s)
- Chelsea R Bulock
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Xuanxuan Xing
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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41
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Spontaneous Polyploids and Antimutators Compete During the Evolution of Saccharomyces cerevisiae Mutator Cells. Genetics 2020; 215:959-974. [PMID: 32513814 PMCID: PMC7404223 DOI: 10.1534/genetics.120.303333] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 05/22/2020] [Indexed: 02/02/2023] Open
Abstract
Mutations affecting DNA polymerase exonuclease domains or mismatch repair (MMR) generate "mutator" phenotypes capable of driving tumorigenesis. Cancers with both defects exhibit an explosive increase in mutation burden that appears to reach a threshold, consistent with selection acting against further mutation accumulation. In Saccharomyces cerevisiae haploid yeast, simultaneous defects in polymerase proofreading and MMR select for "antimutator" mutants that suppress the mutator phenotype. We report here that spontaneous polyploids also escape this "error-induced extinction" and routinely outcompete antimutators in evolved haploid cultures. We performed similar experiments to explore how diploid yeast adapt to the mutator phenotype. We first evolved cells with homozygous mutations affecting polymerase δ proofreading and MMR, which we anticipated would favor tetraploid emergence. While tetraploids arose with a low frequency, in most cultures, a single antimutator clone rose to prominence carrying biallelic mutations affecting the polymerase mutator alleles. Variation in mutation rate between subclones from the same culture suggests that there exists continued selection pressure for additional antimutator alleles. We then evolved diploid yeast modeling MMR-deficient cancers with the most common heterozygous exonuclease domain mutation (POLE-P286R). Although these cells grew robustly, within 120 generations, all subclones carried truncating or nonsynonymous mutations in the POLE-P286R homologous allele (pol2-P301R) that suppressed the mutator phenotype as much as 100-fold. Independent adaptive events in the same culture were common. Our findings suggest that analogous tumor cell populations may adapt to the threat of extinction by polyclonal mutations that neutralize the POLE mutator allele and preserve intratumoral genetic diversity for future adaptation.
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42
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Li HD, Lu C, Zhang H, Hu Q, Zhang J, Cuevas IC, Sahoo SS, Aguilar M, Maurais EG, Zhang S, Wang X, Akbay EA, Li GM, Li B, Koduru P, Ly P, Fu YX, Castrillon DH. A PoleP286R mouse model of endometrial cancer recapitulates high mutational burden and immunotherapy response. JCI Insight 2020; 5:138829. [PMID: 32699191 DOI: 10.1172/jci.insight.138829] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/10/2020] [Indexed: 12/18/2022] Open
Abstract
Cancer is instigated by mutator phenotypes, including deficient mismatch repair and p53-associated chromosomal instability. More recently, a distinct class of cancers was identified with unusually high mutational loads due to heterozygous amino acid substitutions (most commonly P286R) in the proofreading domain of DNA polymerase ε, the leading strand replicase encoded by POLE. Immunotherapy has revolutionized cancer treatment, but new model systems are needed to recapitulate high mutational burdens characterizing human cancers and permit study of mechanisms underlying clinical responses. Here, we show that activation of a conditional LSL-PoleP286R allele in endometrium is sufficient to elicit in all animals endometrial cancers closely resembling their human counterparts, including very high mutational burden. Diverse investigations uncovered potentially novel aspects of Pole-driven tumorigenesis, including secondary p53 mutations associated with tetraploidy, and cooperation with defective mismatch repair through inactivation of Msh2. Most significantly, there were robust antitumor immune responses with increased T cell infiltrates, accelerated tumor growth following T cell depletion, and unfailing clinical regression following immune checkpoint therapy. This model predicts that human POLE-driven cancers will prove consistently responsive to immune checkpoint blockade. Furthermore, this is a robust and efficient approach to recapitulate in mice the high mutational burdens and immune responses characterizing human cancers.
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Affiliation(s)
| | | | - He Zhang
- Quantitative Biomedical Research Center, Department of Population and Data Sciences
| | | | | | | | | | | | | | | | | | - Esra A Akbay
- Department of Pathology.,Simmons Comprehensive Cancer Center
| | - Guo-Min Li
- Department of Radiation Oncology.,Advanced Imaging Research Center
| | - Bo Li
- Simmons Comprehensive Cancer Center.,Lyda Hill Department of Bioinformatics.,Department of Immunology
| | | | - Peter Ly
- Department of Pathology.,Simmons Comprehensive Cancer Center.,Department of Cell Biology, and
| | - Yang-Xin Fu
- Department of Pathology.,Simmons Comprehensive Cancer Center.,Department of Immunology
| | - Diego H Castrillon
- Department of Pathology.,Simmons Comprehensive Cancer Center.,Department of Obstetrics & Gynecology, UT Southwestern Medical Center, Dallas, Texas, USA
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43
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Hodel KP, Sun MJS, Ungerleider N, Park VS, Williams LG, Bauer DL, Immethun VE, Wang J, Suo Z, Lu H, McLachlan JB, Pursell ZF. POLE Mutation Spectra Are Shaped by the Mutant Allele Identity, Its Abundance, and Mismatch Repair Status. Mol Cell 2020; 78:1166-1177.e6. [PMID: 32497495 PMCID: PMC8177757 DOI: 10.1016/j.molcel.2020.05.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/10/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022]
Abstract
Human tumors with exonuclease domain mutations in the gene encoding DNA polymerase ε (POLE) have incredibly high mutation burdens. These errors arise in four unique mutation signatures occurring in different relative amounts, the etiologies of which remain poorly understood. We used CRISPR-Cas9 to engineer human cell lines expressing POLE tumor variants, with and without mismatch repair (MMR). Whole-exome sequencing of these cells after defined numbers of population doublings permitted analysis of nascent mutation accumulation. Unlike an exonuclease active site mutant that we previously characterized, POLE cancer mutants readily drive signature mutagenesis in the presence of functional MMR. Comparison of cell line and human patient data suggests that the relative abundance of mutation signatures partitions POLE tumors into distinct subgroups dependent on the nature of the POLE allele, its expression level, and MMR status. These results suggest that different POLE mutants have previously unappreciated differences in replication fidelity and mutagenesis.
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Affiliation(s)
- Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Meijuan J S Sun
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Nathan Ungerleider
- Department of Pathology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Leonard G Williams
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; BioInnovation Program, Tulane University, New Orleans, LA 70112, USA
| | - David L Bauer
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Victoria E Immethun
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Jieqiong Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Zucai Suo
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Hua Lu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - James B McLachlan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA 70112, USA.
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44
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Abstract
Polδ and Polε are the two major replicative polymerases in eukaryotes, but their precise roles at the replication fork remain a subject of debate. A bulk of data supports a model where Polε and Polδ synthesize leading and lagging DNA strands, respectively. However, this model has been difficult to reconcile with the fact that mutations in Polδ have much stronger consequences for genome stability than equivalent mutations in Polε. We provide direct evidence for a long-entertained idea that Polδ can proofread errors made by Polε in addition to its own errors, thus, making a more prominent contribution to mutation avoidance. This paper provides an essential advance in the understanding of the mechanism of eukaryotic DNA replication. During eukaryotic replication, DNA polymerases ε (Polε) and δ (Polδ) synthesize the leading and lagging strands, respectively. In a long-known contradiction to this model, defects in the fidelity of Polε have a much weaker impact on mutagenesis than analogous Polδ defects. It has been previously proposed that Polδ contributes more to mutation avoidance because it proofreads mismatches created by Polε in addition to its own errors. However, direct evidence for this model was missing. We show that, in yeast, the mutation rate increases synergistically when a Polε nucleotide selectivity defect is combined with a Polδ proofreading defect, demonstrating extrinsic proofreading of Polε errors by Polδ. In contrast, combining Polδ nucleotide selectivity and Polε proofreading defects produces no synergy, indicating that Polε cannot correct errors made by Polδ. We further show that Polδ can remove errors made by exonuclease-deficient Polε in vitro. These findings illustrate the complexity of the one-strand–one-polymerase model where synthesis appears to be largely divided, but Polδ proofreading operates on both strands.
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45
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Singh A, Pandey M, Nandakumar D, Raney KD, Yin YW, Patel SS. Excessive excision of correct nucleotides during DNA synthesis explained by replication hurdles. EMBO J 2020; 39:e103367. [PMID: 32037587 PMCID: PMC7073461 DOI: 10.15252/embj.2019103367] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/23/2019] [Accepted: 01/07/2020] [Indexed: 11/25/2022] Open
Abstract
The proofreading exonuclease activity of replicative DNA polymerase excises misincorporated nucleotides during DNA synthesis, but these events are rare. Therefore, we were surprised to find that T7 replisome excised nearly 7% of correctly incorporated nucleotides during leading and lagging strand syntheses. Similar observations with two other DNA polymerases establish its generality. We show that excessive excision of correctly incorporated nucleotides is not due to events such as processive degradation of nascent DNA or spontaneous partitioning of primer‐end to the exonuclease site as a “cost of proofreading”. Instead, we show that replication hurdles, including secondary structures in template, slowed helicase, or uncoupled helicase–polymerase, increase DNA reannealing and polymerase backtracking, and generate frayed primer‐ends that are shuttled to the exonuclease site and excised efficiently. Our studies indicate that active‐site shuttling occurs at a high frequency, and we propose that it serves as a proofreading mechanism to protect primer‐ends from mutagenic extensions.
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Affiliation(s)
- Anupam Singh
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Manjula Pandey
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Divya Nandakumar
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, The University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Y Whitney Yin
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
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46
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Fang H, Barbour JA, Poulos RC, Katainen R, Aaltonen LA, Wong JWH. Mutational processes of distinct POLE exonuclease domain mutants drive an enrichment of a specific TP53 mutation in colorectal cancer. PLoS Genet 2020; 16:e1008572. [PMID: 32012149 PMCID: PMC7018097 DOI: 10.1371/journal.pgen.1008572] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 02/13/2020] [Accepted: 12/17/2019] [Indexed: 01/16/2023] Open
Abstract
Cancer genomes with mutations in the exonuclease domain of Polymerase Epsilon (POLE) present with an extraordinarily high somatic mutation burden. In vitro studies have shown that distinct POLE mutants exhibit different polymerase activity. Yet, genome-wide mutation patterns and driver mutation formation arising from different POLE mutants remains unclear. Here, we curated somatic mutation calls from 7,345 colorectal cancer samples from published studies and publicly available databases. These include 44 POLE mutant samples including 9 with whole genome sequencing data available. The POLE mutant samples were categorized based on the specific POLE mutation present. Mutation spectrum, associations of somatic mutations with epigenomics features and co-occurrence with specific driver mutations were examined across different POLE mutants. We found that different POLE mutants exhibit distinct mutation spectrum with significantly higher relative frequency of C>T mutations in POLE V411L mutants. Our analysis showed that this increase frequency in C>T mutations is not dependent on DNA methylation and not associated with other genomic features and is thus specifically due to DNA sequence context alone. Notably, we found strong association of the TP53 R213* mutation specifically with POLE P286R mutants. This truncation mutation occurs within the TT[C>T]GA context. For C>T mutations, this sequence context is significantly more likely to be mutated in POLE P286R mutants compared with other POLE exonuclease domain mutants. This study refines our understanding of DNA polymerase fidelity and underscores genome-wide mutation spectrum and specific cancer driver mutation formation observed in POLE mutant cancers. Cancer arises through the accumulation of somatic mutations. The way that these somatic mutations form can vary greatly in different cancers. One of the most mutagenic processes that have been identified is caused by mutations within a replicative DNA polymerase known as Polymerase Epsilon (POLE). Cancers with such mutations present with hundreds of thousands of somatic mutations in their genome. Previous cancer genomics studies have identified a number of mutation hotspots in POLE, however how these different POLE mutants behave in affecting mutation distribution has not been studied. Here, we describe the genome-wide mutation profiles of distinct POLE mutant cancers. We find that different mutants indeed result in different mutation profiles and that this can be explained by the different fidelities of these mutants in replicating specific DNA sequences. Significantly, these differences have important implications in cancer formation as we found that a POLE mutation is strongly associated with a specific truncation of the TP53 cancer driver gene. This study furthers our understanding of the POLE mutagenic process in cancer and provide important insights into carcinogenesis in cancers with such mutations.
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Affiliation(s)
- Hu Fang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Jayne A. Barbour
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
- Prince of Wales Clinical School, UNSW Medicine, UNSW Sydney, New South Wales, Australia
| | - Rebecca C. Poulos
- Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
| | - Riku Katainen
- Applied Tumor Genomics Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Lauri A. Aaltonen
- Applied Tumor Genomics Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Jason W. H. Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
- Prince of Wales Clinical School, UNSW Medicine, UNSW Sydney, New South Wales, Australia
- * E-mail:
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47
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Opportunities for new studies of nuclear DNA replication enzymology in budding yeast. Curr Genet 2019; 66:299-302. [PMID: 31493018 DOI: 10.1007/s00294-019-01023-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022]
Abstract
Three major eukaryotic DNA polymerases, Polymerases α, δ, and ε (Pols α, δ, and ε), perform the fundamental process of DNA synthesis at the replication fork both accurately and efficiently. In trying to understand the necessity and flexibility of the polymerase usage, we recently reported that budding yeast cells lacking Pol ε exonuclease and polymerase domains (pol2-16) survive, but have severe growth defects, checkpoint activation, increased level of dNTP pools as well as significant increase in the mutation rates. Herein, we suggest new opportunities to distinguish the roles of Pol ε from those of two other eukaryotic B-family DNA polymerases, Pols δ and ζ.
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48
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POLE proofreading defects: Contributions to mutagenesis and cancer. DNA Repair (Amst) 2019; 76:50-59. [PMID: 30818169 DOI: 10.1016/j.dnarep.2019.02.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/14/2022]
Abstract
DNA polymerases are uniquely poised to contribute to the elevated mutation burdens seen in many human tumors. These mutations can arise through a number of different polymerase-dependent mechanisms, including intrinsic errors made using template DNA and precursor dNTPs free from chemical modifications, misinsertion events opposite chemically damaged template DNA or insertion events using modified nucleotides. While specific DNA repair polymerases have been known to contribute to tumorigenesis, the role of replication polymerases in mutagenesis in human disease has come into sharp focus over the last decade. This review describes how mutations in these replication DNA polymerases help to drive mutagenesis and tumor development, with particular attention to DNA polymerase epsilon. Recent studies using cancer genome sequencing, mutational signature analyses, yeast and mouse models, and the influence of mismatch repair on tumors with DNA polymerase mutations are discussed.
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49
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Parkash V, Kulkarni Y, Ter Beek J, Shcherbakova PV, Kamerlin SCL, Johansson E. Structural consequence of the most frequently recurring cancer-associated substitution in DNA polymerase ε. Nat Commun 2019; 10:373. [PMID: 30670696 PMCID: PMC6342957 DOI: 10.1038/s41467-018-08114-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 12/12/2018] [Indexed: 11/21/2022] Open
Abstract
The most frequently recurring cancer-associated DNA polymerase ε (Pol ε) mutation is a P286R substitution in the exonuclease domain. While originally proposed to increase genome instability by disrupting exonucleolytic proofreading, the P286R variant was later found to be significantly more pathogenic than Pol ε proofreading deficiency per se. The mechanisms underlying its stronger impact remained unclear. Here we report the crystal structure of the yeast orthologue, Pol ε−P301R, complexed with DNA and an incoming dNTP. Structural changes in the protein are confined to the exonuclease domain, with R301 pointing towards the exonuclease site. Molecular dynamics simulations suggest that R301 interferes with DNA binding to the exonuclease site, an outcome not observed with the exonuclease-inactive Pol ε−D290A,E292A variant lacking the catalytic residues. These results reveal a distinct mechanism of exonuclease inactivation by the P301R substitution and a likely basis for its dramatically higher mutagenic and tumorigenic effects. Mutations in the human POLE gene are associated with tumours with high mutational loads. Here the authors provide a structural rationale for the mutagenic activity of the cancer-associated DNA polymerase ε P286R variant.
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Affiliation(s)
- Vimal Parkash
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, SE-90187, Sweden
| | - Yashraj Kulkarni
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala, S-751 23, Sweden
| | - Josy Ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, SE-90187, Sweden
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | | | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, SE-90187, Sweden.
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