1
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Chang VY, He Y, Grohe S, Brady MR, Chan A, Kadam RS, Fang T, Pang A, Pohl K, Tran E, Li M, Kan J, Zhang Y, Lu JJ, Sasine JP, Himburg HA, Yue P, Chute JP. Epidermal growth factor augments the self-renewal capacity of aged hematopoietic stem cells. iScience 2024; 27:110306. [PMID: 39055915 PMCID: PMC11269946 DOI: 10.1016/j.isci.2024.110306] [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: 12/21/2023] [Revised: 02/19/2024] [Accepted: 06/17/2024] [Indexed: 07/28/2024] Open
Abstract
Hematopoietic aging is associated with decreased hematopoietic stem cell (HSC) self-renewal capacity and myeloid skewing. We report that culture of bone marrow (BM) HSCs from aged mice with epidermal growth factor (EGF) suppressed myeloid skewing, increased multipotent colony formation, and increased HSC repopulation in primary and secondary transplantation assays. Mice transplanted with aged, EGF-treated HSCs displayed increased donor cell engraftment within BM HSCs and systemic administration of EGF to aged mice increased HSC self-renewal capacity in primary and secondary transplantation assays. Expression of a dominant negative EGFR in Scl/Tal1+ hematopoietic cells caused increased myeloid skewing and depletion of long term-HSCs in 15-month-old mice. EGF treatment decreased DNA damage in aged HSCs and shifted the transcriptome of aged HSCs from genes regulating cell death to genes involved in HSC self-renewal and DNA repair but had no effect on HSC senescence. These data suggest that EGFR signaling regulates the repopulating capacity of aged HSCs.
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Affiliation(s)
- Vivian Y. Chang
- Division of Hematology-Oncology, Department of Pediatrics, UCLA, Los Angeles, CA, USA
- Children’s Discovery and Innovation Institute, UCLA, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
| | - Yuwei He
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Samantha Grohe
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Morgan R. Brady
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Aldi Chan
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Rucha S. Kadam
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Tiancheng Fang
- Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, CA, USA
| | - Amara Pang
- Division of Hematology/Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Katherine Pohl
- Division of Hematology/Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Evelyn Tran
- Division of Hematology/Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Michelle Li
- Division of Hematology/Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jenny Kan
- Division of Hematology/Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yurun Zhang
- Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Josie J. Lu
- Applied Genomics, Computation and Translational Core, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Joshua P. Sasine
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Heather A. Himburg
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Peibin Yue
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - John P. Chute
- Division of Hematology & Cellular Therapy, Cedars Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars Sinai Medical Center, Los Angeles, CA 90095, USA
- Samuel Oschin Cancer Center, Cedars Sinai Medical Center, Los Angeles, CA 90095, USA
- Department of Medicine, Cedars Sinai Medical Center, Los Angeles, CA 91361, USA
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2
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Németh E, Szüts D. The mutagenic consequences of defective DNA repair. DNA Repair (Amst) 2024; 139:103694. [PMID: 38788323 DOI: 10.1016/j.dnarep.2024.103694] [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: 03/22/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
Multiple separate repair mechanisms safeguard the genome against various types of DNA damage, and their failure can increase the rate of spontaneous mutagenesis. The malfunction of distinct repair mechanisms leads to genomic instability through different mutagenic processes. For example, defective mismatch repair causes high base substitution rates and microsatellite instability, whereas homologous recombination deficiency is characteristically associated with deletions and chromosome instability. This review presents a comprehensive collection of all mutagenic phenotypes associated with the loss of each DNA repair mechanism, drawing on data from a variety of model organisms and mutagenesis assays, and placing greatest emphasis on systematic analyses of human cancer datasets. We describe the latest theories on the mechanism of each mutagenic process, often explained by reliance on an alternative repair pathway or the error-prone replication of unrepaired, damaged DNA. Aided by the concept of mutational signatures, the genomic phenotypes can be used in cancer diagnosis to identify defective DNA repair pathways.
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Affiliation(s)
- Eszter Németh
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary
| | - Dávid Szüts
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary.
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3
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Ben-Tov D, Mafessoni F, Cucuy A, Honig A, Melamed-Bessudo C, Levy AA. Uncovering the dynamics of precise repair at CRISPR/Cas9-induced double-strand breaks. Nat Commun 2024; 15:5096. [PMID: 38877047 PMCID: PMC11178868 DOI: 10.1038/s41467-024-49410-x] [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: 02/06/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
CRISPR/Cas9 is widely used for precise mutagenesis through targeted DNA double-strand breaks (DSBs) induction followed by error-prone repair. A better understanding of this process requires measuring the rates of cutting, error-prone, and precise repair, which have remained elusive so far. Here, we present a molecular and computational toolkit for multiplexed quantification of DSB intermediates and repair products by single-molecule sequencing. Using this approach, we characterize the dynamics of DSB induction, processing and repair at endogenous loci along a 72 h time-course in tomato protoplasts. Combining this data with kinetic modeling reveals that indel accumulation is determined by the combined effect of the rates of DSB induction processing of broken ends, and precise versus error repair. In this study, 64-88% of the molecules were cleaved in the three targets analyzed, while indels ranged between 15-41%. Precise repair accounts for most of the gap between cleavage and error repair, representing up to 70% of all repair events. Altogether, this system exposes flux in the DSB repair process, decoupling induction and repair dynamics, and suggesting an essential role of high-fidelity repair in limiting the efficiency of CRISPR-mediated mutagenesis.
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Affiliation(s)
- Daniela Ben-Tov
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Fabrizio Mafessoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Amit Cucuy
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Arik Honig
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Cathy Melamed-Bessudo
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
| | - Avraham A Levy
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
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4
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Bader AS, Bushell M. iMUT-seq: high-resolution DSB-induced mutation profiling reveals prevalent homologous-recombination dependent mutagenesis. Nat Commun 2023; 14:8419. [PMID: 38110444 PMCID: PMC10728174 DOI: 10.1038/s41467-023-44167-1] [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: 04/01/2022] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most mutagenic form of DNA damage, and play a significant role in cancer biology, neurodegeneration and aging. However, studying DSB-induced mutagenesis is limited by our current approaches. Here, we describe iMUT-seq, a technique that profiles DSB-induced mutations at high-sensitivity and single-nucleotide resolution around endogenous DSBs. By depleting or inhibiting 20 DSB-repair factors we define their mutational signatures in detail, revealing insights into the mechanisms of DSB-induced mutagenesis. Notably, we find that homologous-recombination (HR) is more mutagenic than previously thought, inducing prevalent base substitutions and mononucleotide deletions at distance from the break due to DNA-polymerase errors. Simultaneously, HR reduces translocations, suggesting a primary role of HR is specifically the prevention of genomic rearrangements. The results presented here offer fundamental insights into DSB-induced mutagenesis and have significant implications for our understanding of cancer biology and the development of DDR-targeting chemotherapeutics.
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Affiliation(s)
- Aldo S Bader
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Cancer Research UK/CI, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
- The Gurdon Institute, University of Cambridge, Biochemistry, Cambridge, UK.
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK.
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5
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Al-Jarf R, Karmakar M, Myung Y, Ascher DB. Uncovering the Molecular Drivers of NHEJ DNA Repair-Implicated Missense Variants and Their Functional Consequences. Genes (Basel) 2023; 14:1890. [PMID: 37895239 PMCID: PMC10606680 DOI: 10.3390/genes14101890] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Variants in non-homologous end joining (NHEJ) DNA repair genes are associated with various human syndromes, including microcephaly, growth delay, Fanconi anemia, and different hereditary cancers. However, very little has been done previously to systematically record the underlying molecular consequences of NHEJ variants and their link to phenotypic outcomes. In this study, a list of over 2983 missense variants of the principal components of the NHEJ system, including DNA Ligase IV, DNA-PKcs, Ku70/80 and XRCC4, reported in the clinical literature, was initially collected. The molecular consequences of variants were evaluated using in silico biophysical tools to quantitatively assess their impact on protein folding, dynamics, stability, and interactions. Cancer-causing and population variants within these NHEJ factors were statistically analyzed to identify molecular drivers. A comprehensive catalog of NHEJ variants from genes known to be mutated in cancer was curated, providing a resource for better understanding their role and molecular mechanisms in diseases. The variant analysis highlighted different molecular drivers among the distinct proteins, where cancer-driving variants in anchor proteins, such as Ku70/80, were more likely to affect key protein-protein interactions, whilst those in the enzymatic components, such as DNA-PKcs, were likely to be found in intolerant regions undergoing purifying selection. We believe that the information acquired in our database will be a powerful resource to better understand the role of non-homologous end-joining DNA repair in genetic disorders, and will serve as a source to inspire other investigations to understand the disease further, vital for the development of improved therapeutic strategies.
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Affiliation(s)
- Raghad Al-Jarf
- Structural Biology and Bioinformatics, Department of Biochemistry, University of Melbourne, Parkville, VIC 3052, Australia (M.K.)
- Systems and Computational Biology, Bio21 Institute, University of Melbourne, Parkville, VIC 3052, Australia
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Malancha Karmakar
- Structural Biology and Bioinformatics, Department of Biochemistry, University of Melbourne, Parkville, VIC 3052, Australia (M.K.)
- Systems and Computational Biology, Bio21 Institute, University of Melbourne, Parkville, VIC 3052, Australia
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Yoochan Myung
- Structural Biology and Bioinformatics, Department of Biochemistry, University of Melbourne, Parkville, VIC 3052, Australia (M.K.)
- Systems and Computational Biology, Bio21 Institute, University of Melbourne, Parkville, VIC 3052, Australia
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - David B. Ascher
- Structural Biology and Bioinformatics, Department of Biochemistry, University of Melbourne, Parkville, VIC 3052, Australia (M.K.)
- Systems and Computational Biology, Bio21 Institute, University of Melbourne, Parkville, VIC 3052, Australia
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
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6
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Barbier MT, Del Valle L. Co-Detection of EBV and Human Polyomavirus JCPyV in a Case of AIDS-Related Multifocal Primary Central Nervous System Diffuse Large B-Cell Lymphoma. Viruses 2023; 15:755. [PMID: 36992464 PMCID: PMC10059075 DOI: 10.3390/v15030755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
The human neurotropic Polyomavirus JCPyV is the widespread opportunistic causative pathogen of the fatal demyelinating disease progressive multifocal leukoencephalopathy; however, it has also been implicated in the oncogenesis of several types of cancers. It causes brain tumors when intracerebrally inoculated into rodents, and genomic sequences of different strains and expression of the viral protein large T-Antigen have been detected in a wide variety of glial brain tumors and CNS lymphomas. Here, we present a case of an AIDS-related multifocal primary CNS lymphoma in which JCPyV genomic sequences of the three regions of JCPyV and expression of T-Antigen were detected by PCR and immunohistochemistry, respectively. No capsid proteins were detected, ruling out active JCPyV replication. Sequencing of the control region revealed that Mad-4 was the strain of JCPyV present in tumor cells. In addition, expression of viral proteins LMP and EBNA-1 from another ubiquitous oncogenic virus, Epstein-Barr, was also detected in the same lymphocytic neoplastic cells, co-localizing with JCPyV T-Antigen, suggesting a potential collaboration between these two viruses in the process of malignant transformation of B-lymphocytes, which are the site of latency and reactivation for both viruses.
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Affiliation(s)
- Mallory T. Barbier
- Louisiana Cancer Research Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Luis Del Valle
- Louisiana Cancer Research Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
- Department of Pathology, Louisiana State University School of Medicine, New Orleans, LA 70112, USA
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7
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Malashetty V, Au A, Chavez J, Hanna M, Chu J, Penna J, Cortes P. The DNA binding domain and the C-terminal region of DNA Ligase IV specify its role in V(D)J recombination. PLoS One 2023; 18:e0282236. [PMID: 36827388 PMCID: PMC9956705 DOI: 10.1371/journal.pone.0282236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/09/2023] [Indexed: 02/26/2023] Open
Abstract
DNA Ligase IV is responsible for the repair of DNA double-strand breaks (DSB), including DSBs that are generated during V(D)J recombination. Like other DNA ligases, Ligase IV contains a catalytic core with three subdomains-the DNA binding (DBD), the nucleotidyltransferase (NTD), and the oligonucleotide/oligosaccharide-fold subdomain (OBD). Ligase IV also has a unique C-terminal region that includes two BRCT domains, a nuclear localization signal sequence and a stretch of amino acid that participate in its interaction with XRCC4. Out of the three mammalian ligases, Ligase IV is the only ligase that participates in and is required for V(D)J recombination. Identification of the minimal domains within DNA Ligase IV that contribute to V(D)J recombination has remained unresolved. The interaction of the Ligase IV DNA binding domain with Artemis, and the interaction of its C-terminal region with XRCC4, suggest that both of these regions that also interact with the Ku70/80 heterodimer are important and might be sufficient for mediating participation of DNA Ligase IV in V(D)J recombination. This hypothesis was investigated by generating chimeric ligase proteins by swapping domains, and testing their ability to rescue V(D)J recombination in Ligase IV-deficient cells. We demonstrate that a fusion protein containing Ligase I NTD and OBDs flanked by DNA Ligase IV DBD and C-terminal region is sufficient to support V(D)J recombination. This chimeric protein, which we named Ligase 37, complemented formation of coding and signal joints. Coding joints generated with Ligase 37 were shorter than those observed with wild type DNA Ligase IV. The shorter length was due to increased nucleotide deletions and decreased nucleotide insertions. Additionally, overexpression of Ligase 37 in a mouse pro-B cell line supported a shift towards shorter coding joints. Our findings demonstrate that the ability of DNA Ligase IV to participate in V(D)J recombination is in large part mediated by its DBD and C-terminal region.
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Affiliation(s)
- Vidyasagar Malashetty
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Audrey Au
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, NY, United States of America
| | - Jose Chavez
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Mary Hanna
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Jennifer Chu
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Jesse Penna
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Patricia Cortes
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, NY, United States of America
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8
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Cheng Z, Wang Y, Guo L, Li J, Zhang W, Zhang C, Liu Y, Huang Y, Xu K. Ku70 affects the frequency of chromosome translocation in human lymphocytes after radiation and T-cell acute lymphoblastic leukemia. Radiat Oncol 2022; 17:144. [PMID: 35986335 PMCID: PMC9389784 DOI: 10.1186/s13014-022-02113-3] [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: 08/30/2021] [Accepted: 08/05/2022] [Indexed: 11/23/2022] Open
Abstract
Background As one of the most common chromosomal causes, chromosome translocation leads to T-cell acute lymphoblastic leukemia (T-ALL). Ku70 is one of the key factors of error-prone DNA repair and it may end in translocation. So far, the direct correlation between Ku70 and translocation has not been assessed. This study aimed to investigate the association between Ku70 and translocation in human lymphocytes after radiation and T-ALL. Methods Peripheral blood lymphocytes (PBLs) from volunteers and human lymphocyte cell line AHH-1 were irradiated with X-rays to form the chromosome translocations. Phytohemagglutinin (PHA) was used to stimulate lymphocytes. The frequency of translocation was detected by fluorescence in situ hybridization (FISH). Meanwhile, the expression of Ku70 was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. Furthermore, Ku70 interference, overexpression and chemical inhibition were used in AHH-1 cell lines to confirm the correlation. Finally, the expression of Ku70 in T-ALL samples with or without translocation was detected. Results The expression of Ku70 and frequencies of translocation were both significantly increased in PBLs after being irradiated by X-rays, and a positive correlation between the expression (both mRNA and protein level) of Ku70 and the frequency of translocation was detected (r = 0.4877, P = 0.004; r = 0.3038, P = 0.0358 respectively). Moreover, Ku70 interference decreased the frequency of translocations, while the frequency of translocations was not significantly affected after Ku70 overexpression. The expression of Ku70 and frequencies of translocation were both significantly increased in cells after irradiation, combined with chemical inhibition (P < 0.01). The protein level and mRNA level of Ku70 in T-ALL with translocation were obviously higher than T-ALL with normal karyotype (P = 0.009, P = 0.049 respectively). Conclusions Ku70 is closely associated with the frequency of chromosome translocation in human lymphocytes after radiation and T-ALL. Ku70 might be a radiation damage biomarker and a potential tumor therapy target. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-022-02113-3.
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9
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Michel N, Young HMR, Atkin ND, Arshad U, Al-Humadi R, Singh S, Manukyan A, Gore L, Burbulis IE, Wang YH, McConnell MJ. Transcription-associated DNA DSBs activate p53 during hiPSC-based neurogenesis. Sci Rep 2022; 12:12156. [PMID: 35840793 PMCID: PMC9287420 DOI: 10.1038/s41598-022-16516-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/11/2022] [Indexed: 11/09/2022] Open
Abstract
Neurons are overproduced during cerebral cortical development. Neural progenitor cells (NPCs) divide rapidly and incur frequent DNA double-strand breaks (DSBs) throughout cortical neurogenesis. Although half of the neurons born during neurodevelopment die, many neurons with inaccurate DNA repair survive leading to brain somatic mosaicism. Recurrent DNA DSBs during neurodevelopment are associated with both gene expression level and gene length. We used imaging flow cytometry and a genome-wide DNA DSB capture approach to quantify and map DNA DSBs during human induced pluripotent stem cell (hiPSC)-based neurogenesis. Reduced p53 signaling was brought about by knockdown (p53KD); p53KD led to elevated DNA DSB burden in neurons that was associated with gene expression level but not gene length in neural progenitor cells (NPCs). Furthermore, DNA DSBs incurred from transcriptional, but not replicative, stress lead to p53 activation in neurotypical NPCs. In p53KD NPCs, DNA DSBs accumulate at transcription start sites of genes that are associated with neurological and psychiatric disorders. These findings add to a growing understanding of how neuronal genome dynamics are engaged by high transcriptional or replicative burden during neurodevelopment.
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Affiliation(s)
- Nadine Michel
- Neuroscience Graduate Program, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Heather M Raimer Young
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Naomi D Atkin
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Umar Arshad
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Reem Al-Humadi
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Sandeep Singh
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Arkadi Manukyan
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Lana Gore
- Lieber Institute for Brain Development, 855 N. Wolfe St., Ste. 300, Baltimore, MD, 21205, USA
| | - Ian E Burbulis
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
- Sede de la Patagonia, Facultad de Medicina y Ciencias, Universidad San Sebastián, Puerto Montt, Chile
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908, USA
| | - Michael J McConnell
- Lieber Institute for Brain Development, 855 N. Wolfe St., Ste. 300, Baltimore, MD, 21205, USA.
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10
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Abstract
The rapid development of CRISPR-Cas genome editing tools has greatly changed the way to conduct research and holds tremendous promise for clinical applications. During genome editing, CRISPR-Cas enzymes induce DNA breaks at the target sites and subsequently the DNA repair pathways are recruited to generate diverse editing outcomes. Besides off-target cleavage, unwanted editing outcomes including chromosomal structural variations and exogenous DNA integrations have recently raised concerns for clinical safety. To eliminate these unwanted editing byproducts, we need to explore the underlying mechanisms for the formation of diverse editing outcomes from the perspective of DNA repair. Here, we describe the involved DNA repair pathways in sealing Cas enzyme-induced DNA double-stranded breaks and discuss the origins and effects of unwanted editing byproducts on genome stability. Furthermore, we propose the potential risk of inhibiting DNA repair pathways to enhance gene editing. The recent combined studies of DNA repair and CRISPR-Cas editing provide a framework for further optimizing genome editing to enhance editing safety.
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11
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Ploessl D, Zhao Y, Cao M, Ghosh S, Lopez C, Sayadi M, Chudalayandi S, Severin A, Huang L, Gustafson M, Shao Z. A repackaged CRISPR platform increases homology-directed repair for yeast engineering. Nat Chem Biol 2022; 18:38-46. [PMID: 34711982 DOI: 10.1038/s41589-021-00893-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 09/09/2021] [Indexed: 12/14/2022]
Abstract
Inefficient homology-directed repair (HDR) constrains CRISPR-Cas9 genome editing in organisms that preferentially employ nonhomologous end joining (NHEJ) to fix DNA double-strand breaks (DSBs). Current strategies used to alleviate NHEJ proficiency involve NHEJ disruption. To confer precision editing without NHEJ disruption, we identified the shortcomings of the conventional CRISPR platforms and developed a CRISPR platform-lowered indel nuclease system enabling accurate repair (LINEAR)-which enhanced HDR rates (to 67-100%) compared to those in previous reports using conventional platforms in four NHEJ-proficient yeasts. With NHEJ preserved, we demonstrate its ability to survey genomic landscapes, identifying loci whose spatiotemporal genomic architectures yield favorable expression dynamics for heterologous pathways. We present a case study that deploys LINEAR precision editing and NHEJ-mediated random integration to rapidly engineer and optimize a microbial factory to produce (S)-norcoclaurine. Taken together, this work demonstrates how to leverage an antagonizing pair of DNA DSB repair pathways to expand the current collection of microbial factories.
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Affiliation(s)
- Deon Ploessl
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Yuxin Zhao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Mingfeng Cao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Saptarshi Ghosh
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Carmen Lopez
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,Interdepartmental Microbiology Program, Iowa State University, Ames, IA, USA
| | - Maryam Sayadi
- The Genome Informatics Facility, Iowa State University, Ames, IA, USA
| | - Siva Chudalayandi
- The Genome Informatics Facility, Iowa State University, Ames, IA, USA
| | - Andrew Severin
- The Genome Informatics Facility, Iowa State University, Ames, IA, USA
| | - Lei Huang
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | - Marissa Gustafson
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA. .,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA. .,Interdepartmental Microbiology Program, Iowa State University, Ames, IA, USA. .,Bioeconomy Institute, Iowa State University, Ames, IA, USA. .,The Ames Laboratory, Ames, IA, USA. .,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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12
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Mancini M, Magnani E, Macchi F, Bonapace IM. The multi-functionality of UHRF1: epigenome maintenance and preservation of genome integrity. Nucleic Acids Res 2021; 49:6053-6068. [PMID: 33939809 PMCID: PMC8216287 DOI: 10.1093/nar/gkab293] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 04/02/2021] [Accepted: 04/12/2021] [Indexed: 12/23/2022] Open
Abstract
During S phase, the cooperation between the macromolecular complexes regulating DNA synthesis, epigenetic information maintenance and DNA repair is advantageous for cells, as they can rapidly detect DNA damage and initiate the DNA damage response (DDR). UHRF1 is a fundamental epigenetic regulator; its ability to coordinate DNA methylation and histone code is unique across proteomes of different species. Recently, UHRF1’s role in DNA damage repair has been explored and recognized to be as important as its role in maintaining the epigenome. UHRF1 is a sensor for interstrand crosslinks and a determinant for the switch towards homologous recombination in the repair of double-strand breaks; its loss results in enhanced sensitivity to DNA damage. These functions are finely regulated by specific post-translational modifications and are mediated by the SRA domain, which binds to damaged DNA, and the RING domain. Here, we review recent studies on the role of UHRF1 in DDR focusing on how it recognizes DNA damage and cooperates with other proteins in its repair. We then discuss how UHRF1’s epigenetic abilities in reading and writing histone modifications, or its interactions with ncRNAs, could interlace with its role in DDR.
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Affiliation(s)
- Monica Mancini
- Department of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio, VA 21052, Italy
| | - Elena Magnani
- Program in Biology, New York University Abu Dhabi, Abu Dhabi, PO Box 129188, United Arab Emirates
| | - Filippo Macchi
- Program in Biology, New York University Abu Dhabi, Abu Dhabi, PO Box 129188, United Arab Emirates
| | - Ian Marc Bonapace
- Department of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio, VA 21052, Italy
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13
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Gresakova V, Novosadova V, Prochazkova M, Prochazka J, Sedlacek R. Dual role of Fam208a during zygotic cleavage and early embryonic development. Exp Cell Res 2021; 406:112723. [PMID: 34216590 DOI: 10.1016/j.yexcr.2021.112723] [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: 06/11/2021] [Accepted: 06/27/2021] [Indexed: 11/15/2022]
Abstract
Maintenance of genome stability is essential for every living cell as genetic information is repeatedly challenged during DNA replication in each cell division event. Errors, defects, delays, and mistakes that arise during mitosis or meiosis lead to an activation of DNA repair processes and in case of their failure, programmed cell death, i.e. apoptosis, could be initiated. Fam208a is a protein whose importance in heterochromatin maintenance has been described recently. In this work, we describe the crucial role of Fam208a in sustaining genome stability during cellular division. The targeted depletion of Fam208a in mice using CRISPR/Cas9 led to embryonic lethality before E12.5. We also used the siRNA approach to downregulate Fam208a in zygotes to avoid the influence of maternal RNA in the early stages of development. This early downregulation increased arresting of the embryonal development at the two-cell stage and the occurrence of multipolar spindles formation. To investigate this further, we used the yeast two-hybrid (Y2H) system and identified new putative interaction partners Gpsm2, Svil, and Itgb3bp. Their co-expression with Fam208a was assessed by RT-qPCR profiling and in situ hybridization [1] in multiple murine tissues. Based on these results we proposed that Fam208a functions within the HUSH complex by interaction with Mphosph8 as these proteins are not only able to physically interact but also co-localise. We are bringing new evidence that Fam208a is a multi-interacting protein affecting genome stability on the cell division level at the earliest stages of development and by interaction with methylation complex in adult tissues. In addition to its epigenetic functions, Fam208a appears to have an important role in the zygotic division, possibly via interaction with newly identified putative partners Gpsm2, Svil, and Itgb3bp.
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Affiliation(s)
- Veronika Gresakova
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic; Palacky University in Olomouc, Faculty of Medicine and Dentistry, Hněvotínská 3, 775 15, Olomouc, Czech Republic.
| | - Vendula Novosadova
- Czech Centre of Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic.
| | - Michaela Prochazkova
- Czech Centre of Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic.
| | - Jan Prochazka
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic; Czech Centre of Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic.
| | - Radislav Sedlacek
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic; Czech Centre of Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50, Vestec, Czech Republic.
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14
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Analysis of chromatid-break-repair detects a homologous recombination to non-homologous end-joining switch with increasing load of DNA double-strand breaks. Mutat Res 2021; 867:503372. [PMID: 34266628 DOI: 10.1016/j.mrgentox.2021.503372] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022]
Abstract
We recently reported that when low doses of ionizing radiation induce low numbers of DNA double-strand breaks (DSBs) in G2-phase cells, about 50 % of them are repaired by homologous recombination (HR) and the remaining by classical non-homologous end-joining (c-NHEJ). However, with increasing DSB-load, the contribution of HR drops to undetectable (at ∼10 Gy) as c-NHEJ dominates. It remains unknown whether the approximately equal shunting of DSBs between HR and c-NHEJ at low radiation doses and the predominant shunting to c-NHEJ at high doses, applies to every DSB, or whether the individual characteristics of each DSB generate processing preferences. When G2-phase cells are irradiated, only about 10 % of the induced DSBs break the chromatids. This breakage allows analysis of the processing of this specific subset of DSBs using cytogenetic methods. Notably, at low radiation doses, these DSBs are almost exclusively processed by HR, suggesting that chromatin characteristics awaiting characterization underpin chromatid breakage and determine the preferential engagement of HR. Strikingly, we also discovered that with increasing radiation dose, a pathway switch to c-NHEJ occurs in the processing of this subset of DSBs. Here, we confirm and substantially extend our initial observations using additional methodologies. Wild-type cells, as well as HR and c-NHEJ mutants, are exposed to a broad spectrum of radiation doses and their response analyzed specifically in G2 phase. Our results further consolidate the observation that at doses <2 Gy, HR is the main option in the processing of the subset of DSBs generating chromatid breaks and that a pathway switch at doses between 4-6 Gy allows the progressive engagement of c-NHEJ. PARP1 inhibition, irrespective of radiation dose, leaves chromatid break repair unaffected suggesting that the contribution of alternative end-joining is undetectable under these experimental conditions.
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15
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Abbasi S, Parmar G, Kelly RD, Balasuriya N, Schild-Poulter C. The Ku complex: recent advances and emerging roles outside of non-homologous end-joining. Cell Mol Life Sci 2021; 78:4589-4613. [PMID: 33855626 PMCID: PMC11071882 DOI: 10.1007/s00018-021-03801-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022]
Abstract
Since its discovery in 1981, the Ku complex has been extensively studied under multiple cellular contexts, with most work focusing on Ku in terms of its essential role in non-homologous end-joining (NHEJ). In this process, Ku is well-known as the DNA-binding subunit for DNA-PK, which is central to the NHEJ repair process. However, in addition to the extensive study of Ku's role in DNA repair, Ku has also been implicated in various other cellular processes including transcription, the DNA damage response, DNA replication, telomere maintenance, and has since been studied in multiple contexts, growing into a multidisciplinary point of research across various fields. Some advances have been driven by clarification of Ku's structure, including the original Ku crystal structure and the more recent Ku-DNA-PKcs crystallography, cryogenic electron microscopy (cryoEM) studies, and the identification of various post-translational modifications. Here, we focus on the advances made in understanding the Ku heterodimer outside of non-homologous end-joining, and across a variety of model organisms. We explore unique structural and functional aspects, detail Ku expression, conservation, and essentiality in different species, discuss the evidence for its involvement in a diverse range of cellular functions, highlight Ku protein interactions and recent work concerning Ku-binding motifs, and finally, we summarize the clinical Ku-related research to date.
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Affiliation(s)
- Sanna Abbasi
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Gursimran Parmar
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Rachel D Kelly
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Nileeka Balasuriya
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada.
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16
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Lee SY, Kim JJ, Miller KM. Emerging roles of RNA modifications in genome integrity. Brief Funct Genomics 2020; 20:106-112. [PMID: 33279952 DOI: 10.1093/bfgp/elaa022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 12/19/2022] Open
Abstract
Post-translational modifications of proteins are well-established participants in DNA damage response (DDR) pathways, which function in the maintenance of genome integrity. Emerging evidence is starting to reveal the involvement of modifications on RNA in the DDR. RNA modifications are known regulators of gene expression but how and if they participate in DNA repair and genome maintenance has been poorly understood. Here, we review several studies that have now established RNA modifications as key components of DNA damage responses. RNA modifying enzymes and the binding proteins that recognize these modifications localize to and participate in the repair of UV-induced and DNA double-strand break lesions. RNA modifications have a profound effect on DNA-RNA hybrids (R-loops) at DNA damage sites, a structure known to be involved in DNA repair and genome stability. Given the importance of the DDR in suppressing mutations and human diseases such as neurodegeneration, immunodeficiencies, cancer and aging, RNA modification pathways may be involved in human diseases not solely through their roles in gene expression but also by their ability to impact DNA repair and genome stability.
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Affiliation(s)
- Seo Yun Lee
- Miller laboratory at the University of Texas at Austin
| | - Jae Jin Kim
- Miller laboratory at the University of Texas at Austin
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17
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Fang T, Zhang Y, Chang VY, Roos M, Termini CM, Signaevskaia L, Quarmyne M, Lin PK, Pang A, Kan J, Yan X, Javier A, Pohl K, Zhao L, Scott P, Himburg HA, Chute JP. Epidermal growth factor receptor-dependent DNA repair promotes murine and human hematopoietic regeneration. Blood 2020; 136:441-454. [PMID: 32369572 PMCID: PMC7378456 DOI: 10.1182/blood.2020005895] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
Chemotherapy and irradiation cause DNA damage to hematopoietic stem cells (HSCs), leading to HSC depletion and dysfunction and the risk of malignant transformation over time. Extrinsic regulation of HSC DNA repair is not well understood, and therapies to augment HSC DNA repair following myelosuppression remain undeveloped. We report that epidermal growth factor receptor (EGFR) regulates DNA repair in HSCs following irradiation via activation of the DNA-dependent protein kinase-catalytic subunit (DNA-PKcs) and nonhomologous end joining (NHEJ). We show that hematopoietic regeneration in vivo following total body irradiation is dependent upon EGFR-mediated repair of DNA damage via activation of DNA-PKcs. Conditional deletion of EGFR in hematopoietic stem and progenitor cells (HSPCs) significantly decreased DNA-PKcs activity following irradiation, causing increased HSC DNA damage and depressed HSC recovery over time. Systemic administration of epidermal growth factor (EGF) promoted HSC DNA repair and rapid hematologic recovery in chemotherapy-treated mice and had no effect on acute myeloid leukemia growth in vivo. Further, EGF treatment drove the recovery of human HSCs capable of multilineage in vivo repopulation following radiation injury. Whole-genome sequencing analysis revealed no increase in coding region mutations in HSPCs from EGF-treated mice, but increased intergenic copy number variant mutations were detected. These studies demonstrate that EGF promotes HSC DNA repair and hematopoietic regeneration in vivo via augmentation of NHEJ. EGF has therapeutic potential to promote human hematopoietic regeneration, and further studies are warranted to assess long-term hematopoietic effects.
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Affiliation(s)
| | | | - Vivian Y Chang
- Pediatric Hematology/Oncology
- Jonsson Comprehensive Cancer Center
| | - Martina Roos
- Jonsson Comprehensive Cancer Center
- Division of Hematology/Oncology, Department of Medicine
- Broad Stem Cell Research Center, and
| | | | | | | | - Paulina K Lin
- Division of Hematology/Oncology, Department of Medicine
| | - Amara Pang
- Division of Hematology/Oncology, Department of Medicine
| | - Jenny Kan
- Division of Hematology/Oncology, Department of Medicine
| | - Xiao Yan
- Department of Molecular and Medical Pharmacology
| | - Anna Javier
- Division of Hematology/Oncology, Department of Medicine
| | | | - Liman Zhao
- Division of Hematology/Oncology, Department of Medicine
| | - Peter Scott
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA
| | | | - John P Chute
- Jonsson Comprehensive Cancer Center
- Division of Hematology/Oncology, Department of Medicine
- Broad Stem Cell Research Center, and
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18
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DNA-PK in human malignant disorders: Mechanisms and implications for pharmacological interventions. Pharmacol Ther 2020; 215:107617. [PMID: 32610116 DOI: 10.1016/j.pharmthera.2020.107617] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
The DNA-PK holoenzyme is a fundamental element of the DNA damage response machinery (DDR), which is responsible for cellular genomic stability. Consequently, and predictably, over the last decades since its identification and characterization, numerous pre-clinical and clinical studies reported observations correlating aberrant DNA-PK status and activity with cancer onset, progression and responses to therapeutic modalities. Notably, various studies have established in recent years the role of DNA-PK outside the DDR network, corroborating its role as a pleiotropic complex involved in transcriptional programs that operate biologic processes as epithelial to mesenchymal transition (EMT), hypoxia, metabolism, nuclear receptors signaling and inflammatory responses. In particular tumor entities as prostate cancer, immense research efforts assisted mapping and describing the overall signaling networks regulated by DNA-PK that control metastasis and tumor progression. Correspondingly, DNA-PK emerges as an obvious therapeutic target in cancer and data pertaining to various pharmacological approaches have been published, largely in context of combination with DNA-damaging agents (DDAs) that act by inflicting DNA double strand breaks (DSBs). Currently, new generation inhibitors are tested in clinical trials. Several excellent reviews have been published in recent years covering the biology of DNA-PK and its role in cancer. In the current article we are aiming to systematically describe the main findings on DNA-PK signaling in major cancer types, focusing on both preclinical and clinical reports and present a detailed current status of the DNA-PK inhibitors repertoire.
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19
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Hattori A, Fukami M. Established and Novel Mechanisms Leading to de novo Genomic Rearrangements in the Human Germline. Cytogenet Genome Res 2020; 160:167-176. [DOI: 10.1159/000507837] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/31/2020] [Indexed: 01/05/2023] Open
Abstract
During gametogenesis, the human genome can acquire various de novo rearrangements. Most constitutional genomic rearrangements are created through 1 of the 4 well-known mechanisms, i.e., nonallelic homologous recombination, erroneous repair after double-strand DNA breaks, replication errors, and retrotransposition. However, recent studies have identified 2 types of extremely complex rearrangements that cannot be simply explained by these mechanisms. The first type consists of chaotic structural changes in 1 or a few chromosomes that result from “chromoanagenesis (an umbrella term that covers chromothripsis, chromoanasynthesis, and chromoplexy).” The other type is large independent rearrangements in multiple chromosomes indicative of “transient multifocal genomic crisis.” Germline chromoanagenesis (chromothripsis) likely occurs predominantly during spermatogenesis or postzygotic embryogenesis, while multifocal genomic crisis appears to be limited to a specific time window during oogenesis and early embryogenesis or during spermatogenesis. This review article introduces the current understanding of the molecular basis of de novo rearrangements in the germline.
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20
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Li W, Bai X, Li J, Zhao Y, Liu J, Zhao H, Liu L, Ding M, Wang Q, Shi FY, Hou M, Ji J, Gao G, Guo R, Sun Y, Liu Y, Xu D. The nucleoskeleton protein IFFO1 immobilizes broken DNA and suppresses chromosome translocation during tumorigenesis. Nat Cell Biol 2019; 21:1273-1285. [DOI: 10.1038/s41556-019-0388-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/09/2019] [Indexed: 01/19/2023]
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21
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Liu Q, Lopez K, Murnane J, Humphrey T, Barcellos-Hoff MH. Misrepair in Context: TGFβ Regulation of DNA Repair. Front Oncol 2019; 9:799. [PMID: 31552165 PMCID: PMC6736563 DOI: 10.3389/fonc.2019.00799] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/06/2019] [Indexed: 12/13/2022] Open
Abstract
Repair of DNA damage protects genomic integrity, which is key to tissue functional integrity. In cancer, the type and fidelity of DNA damage response is the fundamental basis for clinical response to cytotoxic therapy. Here we consider the contribution of transforming growth factor-beta (TGFβ), a ubiquitous, pleotropic cytokine that is abundant in the tumor microenvironment, to therapeutic response. The action of TGFβ is best illustrated in head and neck squamous cell carcinoma (HNSCC). Survival of HNSCC patients with human papilloma virus (HPV) positive cancer is more than double compared to those with HPV-negative HNSCC. Notably, HPV infection profoundly impairs TGFβ signaling. HPV blockade of TGFβ signaling, or pharmaceutical TGFβ inhibition that phenocopies HPV infection, shifts cancer cells from error-free homologous-recombination DNA double-strand-break (DSB) repair to error-prone alternative end-joining (altEJ). Cells using altEJ are more sensitive to standard of care radiotherapy and cisplatin, and are sensitized to PARP inhibitors. Hence, HPV-positive HNSCC is an experiment of nature that provides a strong rationale for the use of TGFβ inhibitors for optimal therapeutic combinations that improve patient outcome.
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Affiliation(s)
- Qi Liu
- Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States.,Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China.,Shenzhen Bay Laboratory (SZBL), Shenzhen, China
| | - Kirsten Lopez
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - John Murnane
- Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Timothy Humphrey
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Mary Helen Barcellos-Hoff
- Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
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22
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Canela A, Maman Y, Huang SYN, Wutz G, Tang W, Zagnoli-Vieira G, Callen E, Wong N, Day A, Peters JM, Caldecott KW, Pommier Y, Nussenzweig A. Topoisomerase II-Induced Chromosome Breakage and Translocation Is Determined by Chromosome Architecture and Transcriptional Activity. Mol Cell 2019; 75:252-266.e8. [PMID: 31202577 PMCID: PMC8170508 DOI: 10.1016/j.molcel.2019.04.030] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/22/2019] [Accepted: 04/21/2019] [Indexed: 12/24/2022]
Abstract
Topoisomerase II (TOP2) relieves torsional stress by forming transient cleavage complex intermediates (TOP2ccs) that contain TOP2-linked DNA breaks (DSBs). While TOP2ccs are normally reversible, they can be "trapped" by chemotherapeutic drugs such as etoposide and subsequently converted into irreversible TOP2-linked DSBs. Here, we have quantified etoposide-induced trapping of TOP2ccs, their conversion into irreversible TOP2-linked DSBs, and their processing during DNA repair genome-wide, as a function of time. We find that while TOP2 chromatin localization and trapping is independent of transcription, it requires pre-existing binding of cohesin to DNA. In contrast, the conversion of trapped TOP2ccs to irreversible DSBs during DNA repair is accelerated 2-fold at transcribed loci relative to non-transcribed loci. This conversion is dependent on proteasomal degradation and TDP2 phosphodiesterase activity. Quantitative modeling shows that only two features of pre-existing chromatin structure-namely, cohesin binding and transcriptional activity-can be used to predict the kinetics of TOP2-induced DSBs.
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Affiliation(s)
- Andres Canela
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA; The Hakubi Center for Advanced Research and Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yaakov Maman
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Shar-Yin N Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, NIH, Bethesda, MD, USA
| | - Gordana Wutz
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Wen Tang
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Guido Zagnoli-Vieira
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Nancy Wong
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Amanda Day
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Keith W Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, 4, Czech Republic
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, NIH, Bethesda, MD, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA.
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23
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Nenarokova A, Záhonová K, Krasilnikova M, Gahura O, McCulloch R, Zíková A, Yurchenko V, Lukeš J. Causes and Effects of Loss of Classical Nonhomologous End Joining Pathway in Parasitic Eukaryotes. mBio 2019; 10:e01541-19. [PMID: 31311886 PMCID: PMC6635534 DOI: 10.1128/mbio.01541-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 01/22/2023] Open
Abstract
We report frequent losses of components of the classical nonhomologous end joining pathway (C-NHEJ), one of the main eukaryotic tools for end joining repair of DNA double-strand breaks, in several lineages of parasitic protists. Moreover, we have identified a single lineage among trypanosomatid flagellates that has lost Ku70 and Ku80, the core C-NHEJ components, and accumulated numerous insertions in many protein-coding genes. We propose a correlation between these two phenomena and discuss the possible impact of the C-NHEJ loss on genome evolution and transition to the parasitic lifestyle.IMPORTANCE Parasites tend to evolve small and compact genomes, generally endowed with a high mutation rate, compared with those of their free-living relatives. However, the mechanisms by which they achieve these features, independently in unrelated lineages, remain largely unknown. We argue that the loss of the classical nonhomologous end joining pathway components may be one of the crucial steps responsible for characteristic features of parasite genomes.
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Affiliation(s)
- Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Marija Krasilnikova
- Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Richard McCulloch
- Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Vyacheslav Yurchenko
- Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
- Life Science Research Centre and Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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24
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Scully R, Panday A, Elango R, Willis NA. DNA double-strand break repair-pathway choice in somatic mammalian cells. Nat Rev Mol Cell Biol 2019; 20:698-714. [PMID: 31263220 DOI: 10.1038/s41580-019-0152-0] [Citation(s) in RCA: 792] [Impact Index Per Article: 158.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2019] [Indexed: 11/09/2022]
Abstract
The major pathways of DNA double-strand break (DSB) repair are crucial for maintaining genomic stability. However, if deployed in an inappropriate cellular context, these same repair functions can mediate chromosome rearrangements that underlie various human diseases, ranging from developmental disorders to cancer. The two major mechanisms of DSB repair in mammalian cells are non-homologous end joining (NHEJ) and homologous recombination. In this Review, we consider DSB repair-pathway choice in somatic mammalian cells as a series of 'decision trees', and explore how defective pathway choice can lead to genomic instability. Stalled, collapsed or broken DNA replication forks present a distinctive challenge to the DSB repair system. Emerging evidence suggests that the 'rules' governing repair-pathway choice at stalled replication forks differ from those at replication-independent DSBs.
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Affiliation(s)
- Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
| | - Arvind Panday
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Rajula Elango
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Nicholas A Willis
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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Fam208a orchestrates interaction protein network essential for early embryonic development and cell division. Exp Cell Res 2019; 382:111437. [PMID: 31112734 DOI: 10.1016/j.yexcr.2019.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/11/2019] [Accepted: 05/14/2019] [Indexed: 11/22/2022]
Abstract
Maintenance of genome stability is essential for every living cell as genetic information is repeatedly challenged during DNA replication in each cell division event. Errors, defects, delays, and mistakes that arise during mitosis or meiosis lead to an activation of DNA repair processes and in case of their failure, programmed cell death, i.e. apoptosis, could be initiated. Fam208a is a protein whose importance in heterochromatin maintenance has been described recently. In this work, we describe the crucial role of Fam208a in sustaining the genome stability during the cellular division. The targeted depletion of Fam208a in mice using CRISPR/Cas9 leads to embryonic lethality before E12.5. We also used the siRNA approach to downregulate Fam208a in zygotes to avoid the influence of maternal RNA in the early stages of development. This early downregulation increased arresting of the embryonal development at the two-cell stage and occurrence of multipolar spindles formation. To investigate this further, we used the yeast two-hybrid (Y2H) system and identified new putative interaction partners Gpsm2, Amn1, Eml1, Svil, and Itgb3bp. Their co-expression with Fam208a was assessed by qRT-PCR profiling and in situ hybridisation [1] in multiple murine tissues. Based on these results we proposed that Fam208a functions within the HUSH complex by interaction with Mphosph8 as these proteins are not only able to physically interact but also co-localise. We are bringing new evidence that Fam208a is multi-interacting protein affecting genome stability on the level of cell division at the earliest stages of development and also by interaction with methylation complex in adult tissues. In addition to its epigenetic functions, Fam208a appears to have an additional role in zygotic division, possibly via interaction with newly identified putative partners Gpsm2, Amn1, Eml1, Svil, and Itgb3bp.
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Eltrombopag promotes DNA repair in human hematopoietic stem and progenitor cells. Exp Hematol 2019; 73:1-6.e6. [PMID: 30986494 DOI: 10.1016/j.exphem.2019.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/14/2019] [Accepted: 03/16/2019] [Indexed: 12/14/2022]
Abstract
A causal link between hematopoietic stem/progenitor cell (HSPC) dysfunction and DNA damage accrual has been proposed. Clinically relevant strategies to maintain genome integrity in these cells are needed. Here we report that eltrombopag, a small molecule agonist of the thrombopoietin (TPO) receptor used in the clinic, promotes DNA double-strand break (DSB) repair in human HSPCs. We found that eltrombopag specifically activates the classic nonhomologous end-joining (C-NHEJ) DNA repair mechanism, a pathway known to support genome integrity. Eltrombopag-mediated DNA repair results in enhanced genome stability, survival, and function of primary human HSPCs, as demonstrated in karyotyping analyses, colony-forming unit assays and after transplantation in immunodeficient NSG mice. Eltrombopag may offer a new therapeutic modality to protect human HSPCs against genome insults.
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DSB structure impacts DNA recombination leading to class switching and chromosomal translocations in human B cells. PLoS Genet 2019; 15:e1008101. [PMID: 30946744 PMCID: PMC6467426 DOI: 10.1371/journal.pgen.1008101] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/16/2019] [Accepted: 03/19/2019] [Indexed: 12/26/2022] Open
Abstract
Class switch recombination (CSR) requires activation-induced cytidine deaminase (AID) to trigger DNA double strand breaks (DSBs) at the immunoglobulin heavy chain (IGH) in B cells. Joining of AID-dependent DSBs within IGH facilitate CSR and effective humoral immunity, but ligation to DSBs in non-IGH chromosomes leads to chromosomal translocations. Thus, the mechanism by which AID-dependent DSBs are repaired requires careful examination. The random activity of AID in IGH leads to a spectrum of DSB structures. In this report, we investigated how DSB structure impacts end-joining leading to CSR and chromosomal translocations in human B cells, for which models of CSR are inefficient and not readily available. Using CRISPR/Cas9 to model AID-dependent DSBs in IGH and non-IGH genes, we found that DSBs with 5’ and 3’ overhangs led to increased processing during end-joining compared to blunt DSBs. We observed that 5’ overhangs were removed and 3’ overhangs were filled in at recombination junctions, suggesting that different subsets of enzymes are required for repair based on DSB polarity. Surprisingly, while Cas9-mediated switching preferentially utilized NHEJ regardless of DSB structure, A-EJ strongly preferred repairing blunt DSBs leading to translocations in the absence of NHEJ. We found that DSB polarity influenced frequency of Cas9-mediated switching and translocations more than overhang length. Lastly, recombination junctions from staggered DSBs exhibited templated insertions, suggesting iterative resection and filling in during repair. Our results demonstrate that DSB structure biases repair towards NHEJ or A-EJ to complete recombination leading to CSR and translocations, thus helping to elucidate the mechanism of genome rearrangements in human B cells. The production of different classes of antibodies/immunoglobulins (IgM, IgG, etc.) is essential for protection against diverse pathogens and effective immunity. This cellular process is triggered by the enzyme activation-induced cytidine deaminase (AID). AID mutates DNA predominantly in antibody genes, generating different types of DNA breaks. Repair of DNA breaks initiated by AID leads to the production of different antibody classes. Erroneous repair of this damage can also lead to chromosomal translocations, a hallmark of lymphomas and other cancers. In this study, we used CRISPR/Cas9 technology to model the different types of DNA breaks physiologically produced by AID. We found that the specific structure of these DNA breaks strongly influenced how they were repaired. That is, different types of DNA breaks inform different modes of rejoining. Our findings show that not all types of DNA breaks are treated equally by genome maintenance machinery in the cell. These observations provide insight into the molecular mechanisms behind antibody-dependent immunity and lymphomagenesis.
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Development of CRISPR/Cas9-mediated gene disruption systems in Giardia lamblia. PLoS One 2019; 14:e0213594. [PMID: 30856211 PMCID: PMC6411161 DOI: 10.1371/journal.pone.0213594] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/25/2019] [Indexed: 12/26/2022] Open
Abstract
Giardia lamblia becomes dormant by differentiation into a water-resistant cyst that can infect a new host. Synthesis of three cyst wall proteins (CWPs) is the fundamental feature of this differentiation. Myeloid leukemia factor (MLF) proteins are involved in cell differentiation, and tumorigenesis in mammals, but little is known about its role in protozoan parasites. We developed a CRISPR/Cas9 system to understand the role of MLF in Giardia. Due to the tetraploid genome in two nuclei of Giardia, it could be hard to disrupt a gene completely in Giardia. We only generated knockdown but not knockout mutants. We found that knockdown of the mlf gene resulted in a significant decrease of cwp gene expression and cyst formation, suggesting a positive role of MLF in encystation. We further used mlf as a model gene to improve the system. The addition of an inhibitor for NHEJ, Scr7, or combining all cassettes for gRNA and Cas9 expression into one plasmid resulted in improved gene disruption efficiencies and a significant decrease in cwp gene expression. Our results provide insights into a positive role of MLF in inducing Giardia differentiation and a useful tool for studies in Giardia.
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Modeling the interplay between DNA-PK, Artemis, and ATM in non-homologous end-joining repair in G1 phase of the cell cycle. J Biol Phys 2019; 45:127-146. [PMID: 30707386 DOI: 10.1007/s10867-018-9519-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 12/28/2018] [Indexed: 01/02/2023] Open
Abstract
Modeling a biological process equips us with more comprehensive insight into the process and a more advantageous experimental design. Non-homologous end joining (NHEJ) is a major double-strand break (DSB) repair pathway that occurs throughout the cell cycle. The objective of the current work is to model the fast and slow phases of NHEJ in G1 phase of the cell cycle following exposure to ionizing radiation (IR). The fast phase contains the major components of NHEJ; Ku70/80 complex, DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and XLF/XRCC4/ligase IV complex (XXL). The slow phase in G1 phase of the cell cycle is associated with more complex lesions and involves ATM and Artemis proteins in addition to the major components. Parameters are mainly obtained from experimental data. The model is successful in predicting the kinetics of DSB foci in 13 normal, ATM-deficient, and Artemis-deficient mammalian fibroblast cell lines in G1 phase of the cell cycle after exposure to low doses of IR. The involvement of ATM provides the model with the potency to be connected to different signaling pathways. Ku70/80 concentration and DNA-binding rate as well as XXL concentration and enzymatic activity are introduced as the best targets for affecting NHEJ DSB repair process. On the basis of the current model, decreasing concentration and DNA binding rate of DNA-PKcs is more effective than inhibiting its activity towards the Artemis protein.
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Prevalence of Mutation-Prone Microhomology-Mediated End Joining in a Chordate Lacking the c-NHEJ DNA Repair Pathway. Curr Biol 2018; 28:3337-3341.e4. [PMID: 30293719 DOI: 10.1016/j.cub.2018.08.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/18/2018] [Accepted: 08/21/2018] [Indexed: 12/20/2022]
Abstract
Classical non-homologous end joining (c-NHEJ), a fundamental pathway that repairs double-strand breaks in DNA, is almost universal in eukaryotes and involves multiple proteins highly conserved from yeast to human [1]. The genes encoding these proteins were not detected in the genome of Oikopleura dioica, a new model system of tunicate larvaceans known for its very compact and highly rearranged genome [2-4]. After showing their absence in the genomes of six other larvacean species, the present study examined how O. dioica oocytes and embryos repair double-strand DNA breaks (DSBs), using two approaches: the injection of linearized plasmids, which resulted in their rapid end joining, and a newly established CRISPR Cas9 technique. In both cases, end joining merged short microhomologous sequences surrounding the break (mainly 4 bp long), thus inducing deletions larger than for the tunicate ascidian Ciona intestinalis and human cells. A relatively high frequency of nucleotide insertions was also observed. Finally, a survey of genomic indels supports the involvement of microhomology-mediated repair in natural conditions. Overall, O. dioica repairs DSBs as other organisms do when their c-NHEJ pathway is experimentally rendered deficient, using another mode of end joining with the same effect as alternative NHEJ (a-NHEJ) or microhomology-mediated end joining (MMEJ) [5-7]. We discuss how the exceptional loss of c-NHEJ and its replacement by a more mutation-prone mechanism may have contributed to reshaping this genome and even been advantageous under pressure for genome compaction.
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Henssen AG, Reed C, Jiang E, Garcia HD, von Stebut J, MacArthur IC, Hundsdoerfer P, Kim JH, de Stanchina E, Kuwahara Y, Hosoi H, Ganem NJ, Dela Cruz F, Kung AL, Schulte JH, Petrini JH, Kentsis A. Therapeutic targeting of PGBD5-induced DNA repair dependency in pediatric solid tumors. Sci Transl Med 2018; 9:9/414/eaam9078. [PMID: 29093183 DOI: 10.1126/scitranslmed.aam9078] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 07/15/2017] [Accepted: 09/25/2017] [Indexed: 12/16/2022]
Abstract
Despite intense efforts, the cure rates of childhood and adult solid tumors are not satisfactory. Resistance to intensive chemotherapy is common, and targets for molecular therapies are largely undefined. We have found that the majority of childhood solid tumors, including rhabdoid tumors, neuroblastoma, medulloblastoma, and Ewing sarcoma, express an active DNA transposase, PGBD5, that can promote site-specific genomic rearrangements in human cells. Using functional genetic approaches, we discovered that mouse and human cells deficient in nonhomologous end joining (NHEJ) DNA repair cannot tolerate the expression of PGBD5. In a chemical screen of DNA damage signaling inhibitors, we identified AZD6738 as a specific sensitizer of PGBD5-dependent DNA damage and apoptosis. We found that expression of PGBD5, but not its nuclease activity-deficient mutant, was sufficient to induce sensitivity to AZD6738. Depletion of endogenous PGBD5 conferred resistance to AZD6738 in human tumor cells. PGBD5-expressing tumor cells accumulated unrepaired DNA damage in response to AZD6738 treatment and underwent apoptosis in both dividing and G1-phase cells in the absence of immediate DNA replication stress. Accordingly, AZD6738 exhibited nanomolar potency against most neuroblastoma, medulloblastoma, Ewing sarcoma, and rhabdoid tumor cells tested while sparing nontransformed human and mouse embryonic fibroblasts in vitro. Finally, treatment with AZD6738 induced apoptosis and regression of human neuroblastoma and medulloblastoma tumors engrafted in immunodeficient mice in vivo. This effect was potentiated by combined treatment with cisplatin, including substantial antitumor activity against patient-derived primary neuroblastoma xenografts. These findings delineate a therapeutically actionable synthetic dependency induced in PGBD5-expressing solid tumors.
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Affiliation(s)
- Anton G Henssen
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.,Berlin Institute of Health, 10178 Berlin, Germany.,Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.,German Cancer Consortium (DKTK), 10117 Berlin, Germany
| | - Casie Reed
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Eileen Jiang
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Heathcliff Dorado Garcia
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Jennifer von Stebut
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Ian C MacArthur
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Patrick Hundsdoerfer
- Berlin Institute of Health, 10178 Berlin, Germany.,Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Jun Hyun Kim
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Elisa de Stanchina
- Antitumor Assessment Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yasumichi Kuwahara
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hajime Hosoi
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Neil J Ganem
- Section of Hematology and Medical Oncology, Department of Pharmacology, Boston University School of Medicine, Boston, MA 02215, USA
| | - Filemon Dela Cruz
- Department of Pediatrics, Weill Cornell Medical College of Cornell University and Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Andrew L Kung
- Department of Pediatrics, Weill Cornell Medical College of Cornell University and Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Johannes H Schulte
- Berlin Institute of Health, 10178 Berlin, Germany.,Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.,German Cancer Consortium (DKTK), 10117 Berlin, Germany.,Deutsches Krebsforschungszentrum Heidelberg, 69120 Heidelberg, Germany
| | - John H Petrini
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Alex Kentsis
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA. .,Department of Pediatrics, Weill Cornell Medical College of Cornell University and Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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Yang C, Zang W, Tang Z, Ji Y, Xu R, Yang Y, Luo A, Hu B, Zhang Z, Liu Z, Zheng X. A20/TNFAIP3 Regulates the DNA Damage Response and Mediates Tumor Cell Resistance to DNA-Damaging Therapy. Cancer Res 2017; 78:1069-1082. [DOI: 10.1158/0008-5472.can-17-2143] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/02/2017] [Accepted: 12/01/2017] [Indexed: 11/16/2022]
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Li T, Liu X, Jiang L, Manfredi J, Zha S, Gu W. Loss of p53-mediated cell-cycle arrest, senescence and apoptosis promotes genomic instability and premature aging. Oncotarget 2017; 7:11838-49. [PMID: 26943586 PMCID: PMC4914251 DOI: 10.18632/oncotarget.7864] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/18/2016] [Indexed: 01/22/2023] Open
Abstract
Although p53-mediated cell cycle arrest, senescence and apoptosis are well accepted as major tumor suppression mechanisms, the loss of these functions does not directly lead to tumorigenesis, suggesting that the precise roles of these canonical activities of p53 need to be redefined. Here, we report that the cells derived from the mutant mice expressing p533KR, an acetylation-defective mutant that fails to induce cell-cycle arrest, senescence and apoptosis, exhibit high levels of aneuploidy upon DNA damage. Moreover, the embryonic lethality caused by the deficiency of XRCC4, a key DNA double strand break repair factor, can be fully rescued in the p533KR/3KR background. Notably, despite high levels of genomic instability, p533KR/3KRXRCC4−/− mice, unlike p53−/− XRCC4−/− mice, are not succumbed to pro-B-cell lymphomas. Nevertheless, p533KR/3KR XRCC4−/− mice display aging-like phenotypes including testicular atrophy, kyphosis, and premature death. Further analyses demonstrate that SLC7A11 is downregulated and that p53-mediated ferroptosis is significantly induced in spleens and testis of p533KR/3KRXRCC4−/− mice. These results demonstrate that the direct role of p53-mediated cell cycle arrest, senescence and apoptosis is to control genomic stability in vivo. Our study not only validates the importance of ferroptosis in p53-mediated tumor suppression in vivo but also reveals that the combination of genomic instability and activation of ferroptosis may promote aging-associated phenotypes.
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Affiliation(s)
- Tongyuan Li
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Xiangyu Liu
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Le Jiang
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - James Manfredi
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Shan Zha
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Wei Gu
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Transient Silencing of DNA Repair Genes Improves Targeted Gene Integration in the Filamentous Fungus Trichoderma reesei. Appl Environ Microbiol 2017; 83:AEM.00535-17. [PMID: 28550064 DOI: 10.1128/aem.00535-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 05/23/2017] [Indexed: 11/20/2022] Open
Abstract
Trichoderma reesei is a filamentous fungus that is used worldwide to produce industrial enzymes. Industrial strains have traditionally been created though systematic strain improvement using mutagenesis and screening approaches. It is also desirable to specifically manipulate the genes of the organism to further improve and to modify the strain. Targeted integration in filamentous fungi is typically hampered by very low frequencies of homologous recombination. To address this limitation, we have developed a simple transient method for silencing genes in T. reesei Using gene-specific small interfering RNAs (siRNAs) targeted to mus53, we could achieve up to 90% knockdown of mus53 mRNA. As a practical example, we demonstrated that transient silencing of DNA repair genes significantly improved homologous integration of DNA at a specific locus in a standard protoplast transformation. The best transient silencing of mus53 with siRNAs in protoplasts could achieve up to 59% marker gene integration.IMPORTANCE The previous solution for improving targeted integration efficiency has been deleting nonhomologous end joining (NHEJ) DNA repair genes. However, deleting these important repair genes may lead to unintended consequences for genomic stability and could lead to the accumulation of spontaneous mutations. Our method of transiently silencing NHEJ repair pathway genes allows recovery of their important repair functions. Here we report a silencing approach for improving targeted DNA integration in filamentous fungi. Furthermore, our transient silencing method is a truly flexible approach that is capable of knocking down the expression of a target gene in growing mycelial cultures, which could facilitate the broad study of gene functions in T. reesei.
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The Role of the Core Non-Homologous End Joining Factors in Carcinogenesis and Cancer. Cancers (Basel) 2017; 9:cancers9070081. [PMID: 28684677 PMCID: PMC5532617 DOI: 10.3390/cancers9070081] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 06/30/2017] [Accepted: 07/03/2017] [Indexed: 12/20/2022] Open
Abstract
DNA double-strand breaks (DSBs) are deleterious DNA lesions that if left unrepaired or are misrepaired, potentially result in chromosomal aberrations, known drivers of carcinogenesis. Pathways that direct the repair of DSBs are traditionally believed to be guardians of the genome as they protect cells from genomic instability. The prominent DSB repair pathway in human cells is the non-homologous end joining (NHEJ) pathway, which mediates template-independent re-ligation of the broken DNA molecule and is active in all phases of the cell cycle. Its role as a guardian of the genome is supported by the fact that defects in NHEJ lead to increased sensitivity to agents that induce DSBs and an increased frequency of chromosomal aberrations. Conversely, evidence from tumors and tumor cell lines has emerged that NHEJ also promotes chromosomal aberrations and genomic instability, particularly in cells that have a defect in one of the other DSB repair pathways. Collectively, the data present a conundrum: how can a single pathway both suppress and promote carcinogenesis? In this review, we will examine NHEJ's role as both a guardian and a disruptor of the genome and explain how underlying genetic context not only dictates whether NHEJ promotes or suppresses carcinogenesis, but also how it alters the response of tumors to conventional therapeutics.
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Nickoloff JA, Boss MK, Allen CP, LaRue SM. Translational research in radiation-induced DNA damage signaling and repair. Transl Cancer Res 2017; 6:S875-S891. [PMID: 30574452 PMCID: PMC6298755 DOI: 10.21037/tcr.2017.06.02] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Radiotherapy is an effective tool in the fight against cancer. It is non-invasive and painless, and with advanced tumor imaging and beam control systems, radiation can be delivered to patients safely, generally with minor or no adverse side effects, accounting for its increasing use against a broad range of tumors. Tumors and normal cells respond to radiation-induced DNA damage by activating a complex network of DNA damage signaling and repair pathways that determine cell fate including survival, death, and genome stability. DNA damage response (DDR) proteins represent excellent targets to augment radiotherapy, and many agents that inhibit key response proteins are being combined with radiation and genotoxic chemotherapy in clinical trials. This review focuses on how insights into molecular mechanisms of DDR pathways are translated to small animal preclinical studies, to clinical studies of naturally occurring tumors in companion animals, and finally to human clinical trials. Companion animal studies, under the umbrella of comparative oncology, have played key roles in the development of clinical radiotherapy throughout its >100-year history. There is growing appreciation that rapid translation of basic knowledge of DNA damage and repair systems to improved radiotherapy practice requires a comprehensive approach that embraces the full spectrum of cancer research, with companion animal clinical trials representing a critical bridge between small animal preclinical studies, and human clinical trials.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Mary-Keara Boss
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Christopher P Allen
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Susan M LaRue
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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Qiu Z, Zhang Z, Roschke A, Varga T, Aplan PD. Generation of Gross Chromosomal Rearrangements by a Single Engineered DNA Double Strand Break. Sci Rep 2017; 7:43156. [PMID: 28225067 PMCID: PMC5320478 DOI: 10.1038/srep43156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/19/2017] [Indexed: 01/08/2023] Open
Abstract
Gross chromosomal rearrangements (GCRs), including translocations, inversions amplifications, and deletions, can be causal events leading to malignant transformation. GCRs are thought to be triggered by DNA double strand breaks (DSBs), which in turn can be spontaneous or induced by external agents (eg. cytotoxic chemotherapy, ionizing radiation). It has been shown that induction of DNA DSBs at two defined loci can produce stable balanced chromosomal translocations, however, a single engineered DNA DSB could not. Herein, we report that although a single engineered DNA DSB in H2AX “knockdown” cells did not generate GCRs, repair of a single engineered DNA DSB in fibroblasts that had ablated H2ax did produce clonal, stable GCRs, including balanced translocations and megabase-pair inversions. Upon correction of the H2ax deficiency, cells no longer generated GCRs following a single engineered DNA DSB. These findings demonstrate that clonal, stable GCRs can be produced by a single engineered DNA DSB in H2ax knockout cells, and that the production of these GCRs is ameliorated by H2ax expression.
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Affiliation(s)
- Zhijun Qiu
- Genetics Branch National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhenhua Zhang
- Genetics Branch National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anna Roschke
- Genetics Branch National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tamas Varga
- Genetics Branch National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter D Aplan
- Genetics Branch National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Jahantigh D, Moghtaderi A, Narooie-Nejad M, Mousavi M, Moossavi M, Salimi S, Mohammadoo-Khorasani M. Carriage of 2R allele at VNTR polymorphous site of XRCC5 gene increases risk of multiple sclerosis in an Iranian population. RUSS J GENET+ 2017. [DOI: 10.1134/s102279541612005x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Koschmann C, Calinescu AA, Nunez FJ, Mackay A, Fazal-Salom J, Thomas D, Mendez F, Kamran N, Dzaman M, Mulpuri L, Krasinkiewicz J, Doherty R, Lemons R, Brosnan-Cashman JA, Li Y, Roh S, Zhao L, Appelman H, Ferguson D, Gorbunova V, Meeker A, Jones C, Lowenstein PR, Castro MG. ATRX loss promotes tumor growth and impairs nonhomologous end joining DNA repair in glioma. Sci Transl Med 2016; 8:328ra28. [PMID: 26936505 DOI: 10.1126/scitranslmed.aac8228] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recent work in human glioblastoma (GBM) has documented recurrent mutations in the histone chaperone protein ATRX. We developed an animal model of ATRX-deficient GBM and showed that loss of ATRX reduces median survival and increases genetic instability. Further, analysis of genome-wide data for human gliomas showed that ATRX mutation is associated with increased mutation rate at the single-nucleotide variant (SNV) level. In mouse tumors, ATRX deficiency impairs nonhomologous end joining and increases sensitivity to DNA-damaging agents that induce double-stranded DNA breaks. We propose that ATRX loss results in a genetically unstable tumor, which is more aggressive when left untreated but is more responsive to double-stranded DNA-damaging agents, resulting in improved overall survival.
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Affiliation(s)
- Carl Koschmann
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA. Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Anda-Alexandra Calinescu
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Felipe J Nunez
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Alan Mackay
- Divisions of Molecular Pathology and Cancer Therapeutics, Institute of Cancer Research, London SM2 5NG, UK
| | - Janet Fazal-Salom
- Divisions of Molecular Pathology and Cancer Therapeutics, Institute of Cancer Research, London SM2 5NG, UK
| | - Daniel Thomas
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Flor Mendez
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Neha Kamran
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Marta Dzaman
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Lakshman Mulpuri
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Johnathon Krasinkiewicz
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Robert Doherty
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Rosemary Lemons
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | | | - Youping Li
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Soyeon Roh
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Lili Zhao
- Department of Biostatistics, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Henry Appelman
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - David Ferguson
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Vera Gorbunova
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Alan Meeker
- Departments of Pathology and Urology, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Chris Jones
- Divisions of Molecular Pathology and Cancer Therapeutics, Institute of Cancer Research, London SM2 5NG, UK
| | - Pedro R Lowenstein
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Maria G Castro
- Departments of Neurosurgery and Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA.
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Shamanna RA, Lu H, de Freitas JK, Tian J, Croteau DL, Bohr VA. WRN regulates pathway choice between classical and alternative non-homologous end joining. Nat Commun 2016; 7:13785. [PMID: 27922005 PMCID: PMC5150655 DOI: 10.1038/ncomms13785] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/01/2016] [Indexed: 11/20/2022] Open
Abstract
Werner syndrome (WS) is an accelerated ageing disorder with genomic instability caused by WRN protein deficiency. Many features seen in WS can be explained by the diverse functions of WRN in DNA metabolism. However, the origin of the large genomic deletions and telomere fusions are not yet understood. Here, we report that WRN regulates the pathway choice between classical (c)- and alternative (alt)-nonhomologous end joining (NHEJ) during DNA double-strand break (DSB) repair. It promotes c-NHEJ via helicase and exonuclease activities and inhibits alt-NHEJ using non-enzymatic functions. When WRN is recruited to the DSBs it suppresses the recruitment of MRE11 and CtIP, and protects the DSBs from 5′ end resection. Moreover, knockdown of Wrn, alone or in combination with Trf2 in mouse embryonic fibroblasts results in increased telomere fusions, which were ablated by Ctip knockdown. We show that WRN regulates alt-NHEJ and shields DSBs from MRE11/CtIP-mediated resection to prevent large deletions and telomere fusions. Werner Syndrome is an accelerated aging disorder marked by genome instability, large deletions and telomere fusions, hallmarks of aberrant DNA repair. Here the authors report a role for the WRN helicase in regulating the choice between classical and alternative non-homologous end-joning.
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Affiliation(s)
- Raghavendra A Shamanna
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Huiming Lu
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Jessica K de Freitas
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Jane Tian
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
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Hartlerode AJ, Willis NA, Rajendran A, Manis JP, Scully R. Complex Breakpoints and Template Switching Associated with Non-canonical Termination of Homologous Recombination in Mammalian Cells. PLoS Genet 2016; 12:e1006410. [PMID: 27832076 PMCID: PMC5104497 DOI: 10.1371/journal.pgen.1006410] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 10/07/2016] [Indexed: 12/11/2022] Open
Abstract
A proportion of homologous recombination (HR) events in mammalian cells resolve by "long tract" gene conversion, reflecting copying of several kilobases from the donor sister chromatid prior to termination. Cells lacking the major hereditary breast/ovarian cancer predisposition genes, BRCA1 or BRCA2, or certain other HR-defective cells, reveal a bias in favor of long tract gene conversion, suggesting that this aberrant HR outcome might be connected with genomic instability. If termination of gene conversion occurs in regions lacking homology with the second end of the break, the normal mechanism of HR termination by annealing (i.e., homologous pairing) is not available and termination must occur by as yet poorly defined non-canonical mechanisms. Here we use a previously described HR reporter to analyze mechanisms of non-canonical termination of long tract gene conversion in mammalian cells. We find that non-canonical HR termination can occur in the absence of the classical non-homologous end joining gene XRCC4. We observe obligatory use of microhomology (MH)-mediated end joining and/or nucleotide addition during rejoining with the second end of the break. Notably, non-canonical HR termination is associated with complex breakpoints. We identify roles for homology-mediated template switching and, potentially, MH-mediated template switching/microhomology-mediated break-induced replication, in the formation of complex breakpoints at sites of non-canonical HR termination. This work identifies non-canonical HR termination as a potential contributor to genomic instability and to the formation of complex breakpoints in cancer.
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Affiliation(s)
- Andrea J. Hartlerode
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nicholas A. Willis
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Anbazhagan Rajendran
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - John P. Manis
- Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ralph Scully
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Tong KI, Ota K, Komuro A, Ueda T, Ito A, Anne Koch C, Okada H. Attenuated DNA damage repair delays therapy-related myeloid neoplasms in a mouse model. Cell Death Dis 2016; 7:e2401. [PMID: 27711078 PMCID: PMC5133969 DOI: 10.1038/cddis.2016.298] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 07/31/2016] [Accepted: 08/22/2016] [Indexed: 12/18/2022]
Abstract
Therapy-related cancers are potentially fatal late life complications for patients who received radio- or chemotherapy. So far, the mouse model showing reduction or delay of these diseases has not been described. We found that the disruption of Aplf in mice moderately attenuated DNA damage repair and, unexpectedly, impeded myeloid neoplasms after exposure to ionizing radiation (IR). Irradiated mutant mice showed higher rates of p53-dependent cell death, fewer chromosomal translocations, and a delay in malignancy-induce;/– mice. Depletion of APLF in non-tumorigenic human cells also markedly reduced the risk of radiation-induced chromosomal aberrations. We therefore conclude that proficient DNA damage repair may promote chromosomal aberrations in normal tissues after irradiation and induce malignant evolution, thus illustrating the potential benefit in sensitizing p53 function by manipulating DNA repair efficiency in cancer patients undergoing genotoxic therapies.
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Affiliation(s)
- Kit I Tong
- The Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, ON, Canada M5G 2M9
| | - Kazushige Ota
- Department of Biochemistry, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Osaka, Japan
| | - Akiyoshi Komuro
- Department of Biochemistry, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Osaka, Japan
| | - Takeshi Ueda
- Department of Biochemistry, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Osaka, Japan
| | - Akihiko Ito
- Department of Pathology, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan
| | - C Anne Koch
- Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada M5G 2M9.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada M5G 2M9
| | - Hitoshi Okada
- The Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, ON, Canada M5G 2M9.,Department of Biochemistry, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Osaka, Japan.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada M5G 2M9.,Anti-Aging Center, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
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Chakraborty A, Tapryal N, Venkova T, Horikoshi N, Pandita RK, Sarker AH, Sarkar PS, Pandita TK, Hazra TK. Classical non-homologous end-joining pathway utilizes nascent RNA for error-free double-strand break repair of transcribed genes. Nat Commun 2016; 7:13049. [PMID: 27703167 PMCID: PMC5059474 DOI: 10.1038/ncomms13049] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/30/2016] [Indexed: 12/30/2022] Open
Abstract
DNA double-strand breaks (DSBs) leading to loss of nucleotides in the transcribed region can be lethal. Classical non-homologous end-joining (C-NHEJ) is the dominant pathway for DSB repair (DSBR) in adult mammalian cells. Here we report that during such DSBR, mammalian C-NHEJ proteins form a multiprotein complex with RNA polymerase II and preferentially associate with the transcribed genes after DSB induction. Depletion of C-NHEJ factors significantly abrogates DSBR in transcribed but not in non-transcribed genes. We hypothesized that nascent RNA can serve as a template for restoring the missing sequences, thus allowing error-free DSBR. We indeed found pre-mRNA in the C-NHEJ complex. Finally, when a DSB-containing plasmid with several nucleotides deleted within the E. coli lacZ gene was allowed time to repair in lacZ-expressing mammalian cells, a functional lacZ plasmid could be recovered from control but not C-NHEJ factor-depleted cells, providing important mechanistic insights into C-NHEJ-mediated error-free DSBR of the transcribed genome. Most adult mammalian cells prefer to repair double-strand DNA breaks though the classical nonhomologous end-joining pathway. Here the authors present evidence that a nascent RNA transcript can serve as a template to facilitate error-free repair.
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Affiliation(s)
- Anirban Chakraborty
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nisha Tapryal
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tatiana Venkova
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nobuo Horikoshi
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Raj K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Altaf H Sarker
- Division of Life Sciences, Department of Cancer and DNA Damage Responses, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Partha S Sarkar
- Department of Neurology and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tej K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Tapas K Hazra
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
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DNA repair gene XRCC7 G6721T variant and susceptibility to colorectal cancer. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2016. [DOI: 10.1016/j.ejmhg.2016.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Ahrabi S, Sarkar S, Pfister SX, Pirovano G, Higgins GS, Porter ACG, Humphrey TC. A role for human homologous recombination factors in suppressing microhomology-mediated end joining. Nucleic Acids Res 2016; 44:5743-57. [PMID: 27131361 PMCID: PMC4937322 DOI: 10.1093/nar/gkw326] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 12/22/2022] Open
Abstract
DNA double-strand breaks (DSBs) are toxic lesions, which if improperly repaired can result in cell death or genomic instability. DSB repair is usually facilitated by the classical non-homologous end joining (C-NHEJ), or homologous recombination (HR) pathways. However, a mutagenic alternative NHEJ pathway, microhomology-mediated end joining (MMEJ), can also be deployed. While MMEJ is suppressed by C-NHEJ, the relationship between HR and MMEJ is less clear. Here, we describe a role for HR genes in suppressing MMEJ in human cells. By monitoring DSB mis-repair using a sensitive HPRT assay, we found that depletion of HR proteins, including BRCA2, BRCA1 or RPA, resulted in a distinct mutational signature associated with significant increases in break-induced mutation frequencies, deletion lengths and the annealing of short regions of microhomology (2-6 bp) across the break-site. This signature was dependent on CtIP, MRE11, POLQ and PARP, and thus indicative of MMEJ. In contrast to CtIP or MRE11, depletion of BRCA1 resulted in increased partial resection and MMEJ, thus revealing a functional distinction between these early acting HR factors. Together these findings indicate that HR factors suppress mutagenic MMEJ following DSB resection.
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Affiliation(s)
- Sara Ahrabi
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Sovan Sarkar
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Sophia X Pfister
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Giacomo Pirovano
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Geoff S Higgins
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Andrew C G Porter
- Gene Targeting Group, Centre for Haematology, Imperial College Faculty of Medicine, London W12 0NN, UK
| | - Timothy C Humphrey
- CRUK MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
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Ligase-4 Deficiency Causes Distinctive Immune Abnormalities in Asymptomatic Individuals. J Clin Immunol 2016; 36:341-53. [PMID: 27063650 DOI: 10.1007/s10875-016-0266-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/07/2016] [Indexed: 01/01/2023]
Abstract
PURPOSE DNA Ligase 4 (LIG4) is a key factor in the non-homologous end-joining (NHEJ) DNA double-strand break repair pathway needed for V(D)J recombination and the generation of the T cell receptor and immunoglobulin molecules. Defects in LIG4 result in a variable syndrome of growth retardation, pancytopenia, combined immunodeficiency, cellular radiosensitivity, and developmental delay. METHODS We diagnosed a patient with LIG4 syndrome by radiosensitivity testing on peripheral blood cells, and established that two of her four healthy siblings carried the same compound heterozygous LIG4 mutations. An extensive analysis of the immune phenotype, cellular radiosensitivity, telomere length, and T and B cell antigen receptor repertoire was performed in all siblings. RESULTS In the three genotypically affected individuals, variable severities of radiosensitivity, alterations of T and B cell counts with an increased percentage of memory cells, and hypogammaglobulinemia, were noticed. Analysis of T and B cell antigen receptor repertoires demonstrated increased usage of alternative microhomology-mediated end-joining (MHMEJ) repair, leading to diminished N nucleotide addition and shorter CDR3 length. However, overall repertoire diversity was preserved. CONCLUSIONS We demonstrate that LIG4 syndrome presents with high clinical variability even within the same family, and that distinctive immunologic abnormalities may be observed also in yet asymptomatic individuals.
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FBXW7 Facilitates Nonhomologous End-Joining via K63-Linked Polyubiquitylation of XRCC4. Mol Cell 2016; 61:419-433. [PMID: 26774286 DOI: 10.1016/j.molcel.2015.12.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 10/05/2015] [Accepted: 12/02/2015] [Indexed: 11/22/2022]
Abstract
FBXW7 is a haploinsufficient tumor suppressor with loss-of-function mutations occurring in human cancers. FBXW7 inactivation causes genomic instability, but the mechanism remains elusive. Here we show that FBXW7 facilitates nonhomologous end-joining (NHEJ) repair and that FBXW7 depletion causes radiosensitization. In response to ionizing radiation, ATM phosphorylates FBXW7 at serine 26 to recruit it to DNA double-strand break (DSB) sites, whereas activated DNA-PKcs phosphorylates XRCC4 at serines 325/326, which promotes binding of XRCC4 to FBXW7. SCF(FBXW7) E3 ligase then promotes polyubiquitylation of XRCC4 at lysine 296 via lysine 63 linkage for enhanced association with the Ku70/80 complex to facilitate NHEJ repair. Consistent with these findings, a small-molecule inhibitor that abrogates XRCC4 polyubiquitylation reduces NHEJ repair. Our study demonstrates one mechanism by which FBXW7 contributes to genome integrity and implies that inactivated FBXW7 in human cancers could be a strategy for increasing the efficacy of radiotherapy.
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Abstract
Chromosome rearrangement plays a causal role in tumorigenesis by contributing to the inactivation of tumor suppressor genes, the dysregulated expression or amplification of oncogenes and the generation of novel gene fusions. Chromosome breaks are important intermediates in this process. How, when and where these breaks arise and the specific mechanisms engaged in their repair strongly influence the resulting patterns of chromosome rearrangement. Here, we review recent progress in understanding how certain distinctive features of the cancer genome, including clustered mutagenesis, tandem segmental duplications, complex breakpoints, chromothripsis, chromoplexy and chromoanasynthesis may arise.
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DNA polymerases δ and λ cooperate in repairing double-strand breaks by microhomology-mediated end-joining in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2015; 112:E6907-16. [PMID: 26607450 DOI: 10.1073/pnas.1507833112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maintenance of genome stability is carried out by a suite of DNA repair pathways that ensure the repair of damaged DNA and faithful replication of the genome. Of particular importance are the repair pathways, which respond to DNA double-strand breaks (DSBs), and how the efficiency of repair is influenced by sequence homology. In this study, we developed a genetic assay in diploid Saccharomyces cerevisiae cells to analyze DSBs requiring microhomologies for repair, known as microhomology-mediated end-joining (MMEJ). MMEJ repair efficiency increased concomitant with microhomology length and decreased upon introduction of mismatches. The central proteins in homologous recombination (HR), Rad52 and Rad51, suppressed MMEJ in this system, suggesting a competition between HR and MMEJ for the repair of a DSB. Importantly, we found that DNA polymerase delta (Pol δ) is critical for MMEJ, independent of microhomology length and base-pairing continuity. MMEJ recombinants showed evidence that Pol δ proofreading function is active during MMEJ-mediated DSB repair. Furthermore, mutations in Pol δ and DNA polymerase 4 (Pol λ), the DNA polymerase previously implicated in MMEJ, cause a synergistic decrease in MMEJ repair. Pol λ showed faster kinetics associating with MMEJ substrates following DSB induction than Pol δ. The association of Pol δ depended on RAD1, which encodes the flap endonuclease needed to cleave MMEJ intermediates before DNA synthesis. Moreover, Pol δ recruitment was diminished in cells lacking Pol λ. These data suggest cooperative involvement of both polymerases in MMEJ.
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50
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Iliakis G, Murmann T, Soni A. Alternative end-joining repair pathways are the ultimate backup for abrogated classical non-homologous end-joining and homologous recombination repair: Implications for the formation of chromosome translocations. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:166-75. [DOI: 10.1016/j.mrgentox.2015.07.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 01/15/2023]
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