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Ning Q, Yang T, Guo X, Huang Y, Gao Y, Liu M, Yang P, Guan Y, Liu N, Wang Y, Chen D. CHB patients with rtA181T-mutated HBV infection are associated with higher risk hepatocellular carcinoma due to increases in mutation rates of tumour suppressor genes. J Viral Hepat 2023; 30:951-958. [PMID: 37735836 DOI: 10.1111/jvh.13886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 09/23/2023]
Abstract
The HBV rtA181T mutation is associated with an increased risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This study aimed to evaluate the mechanism by which rtA181T mutation increases the risk of HCC. We enrolled 470 CHB patients with rtA181T and rtA181V mutation in this study; 68 (22.15%) of the 307 patients with rtA181T mutation and 22 (13.5%) of the 163 patients with rtA181V mutation developed HCC (p < .05). The median follow-up periods were 8.148 and 8.055 years (p > .05). Serum HBV DNA and HBsAg levels in rtA181T-positive patients were similar to that in rtA181V-positive patients. However, the serum HBeAg levels in the rtA181T-positive patients were significantly higher than that in rtA181V-positive patients. In situ hybridization experiments showed that the HBV cccDNA and HBV RNA levels were significantly higher in the liver cancer tissues of patients with the rtA181T mutation compared to that in the tissues of patients with the rtA181V mutation. The percentage of anti-tumour hot-gene site mutations was significantly higher in the rtA181T-positive HCC liver tissue compared to that in the rtA181T-negative HCC liver tissue (7.65% and 4.3%, p < .05). This is the first study to use a large cohort and a follow-up of more than 5 years (average 8 years) to confirm that the rtA181T mutation increased the risk of HCC, and that it could be related to the increase in the mutation rate of hotspots of tumour suppressor genes (CTNNB1, TP53, NRAS and PIK3CA).
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Affiliation(s)
- Qiqi Ning
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Tongwang Yang
- Academician Workstation, Changsha Medical University, Changsha, China
- Hunan Key Laboratory of the Research and Development of Novel Pharmaceutical Preparations, Changsha Medical University, Changsha, China
| | - Xianghua Guo
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Yanxiang Huang
- Clinical laboratory center, Beijing You An Hospital, Capital Medical University, Beijing, China
| | - Yuxue Gao
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Mengcheng Liu
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Pengxiang Yang
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Yuanyue Guan
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Ning Liu
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Yang Wang
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
| | - Dexi Chen
- Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing, China
- Beijing Precision Medicine and Transformation Engineering Technology Research Center of Hepatitis and Liver Cancer, Beijing, China
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2
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Benada J, Alsowaida D, Megeney LA, Sørensen CS. Self-inflicted DNA breaks in cell differentiation and cancer. Trends Cell Biol 2023; 33:850-859. [PMID: 36997393 DOI: 10.1016/j.tcb.2023.03.002] [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: 12/01/2022] [Revised: 03/05/2023] [Accepted: 03/08/2023] [Indexed: 03/30/2023]
Abstract
Self-inflicted DNA strand breaks are canonically linked with cell death pathways and the establishment of genetic diversity in immune and germline cells. Moreover, this form of DNA damage is an established source of genome instability in cancer development. However, recent studies indicate that nonlethal self-inflicted DNA strand breaks play an indispensable but underappreciated role in a variety of cell processes, including differentiation and cancer therapy responses. Mechanistically, these physiological DNA breaks originate from the activation of nucleases, which are best characterized for inducing DNA fragmentation in apoptotic cell death. In this review, we outline the emerging biology of one critical nuclease, caspase-activated DNase (CAD), and how directed activation or deployment of this enzyme can lead to divergent cell fate outcomes.
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Affiliation(s)
- Jan Benada
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen 2200 N, Denmark
| | - Dalal Alsowaida
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute and the Departments of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, K1H 8L6, Canada; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Lynn A Megeney
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute and the Departments of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, K1H 8L6, Canada.
| | - Claus S Sørensen
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen 2200 N, Denmark.
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3
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Pannunzio N, Rangel V, Sterrenberg J, Garawi A, Mezcord V, Folkerts M, Caulderon S, Wang J, Soyfer E, Eng O, Valerin J, Tanjasiri S, Quintero-Rivera F, Masri S, Seldin M, Frock R, Fleischman A. Increased AID Results in Mutations at the CRLF2 Locus Implicated in Latin American ALL Health Disparities. RESEARCH SQUARE 2023:rs.3.rs-3332673. [PMID: 37790327 PMCID: PMC10543404 DOI: 10.21203/rs.3.rs-3332673/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Activation-induced cytidine deaminase (AID) is a B cell-specific base editor required during class switch recombination and somatic hypermutation for B cell maturation and antibody diversification. However, it has also been implicated as a factor in the etiology of several B cell malignancies. Evaluating the AID-induced mutation load in patients at-risk for certain types of blood cancers is critical in assessing disease severity and treatment options. Here, we have developed a digital PCR (dPCR) assay that allows us to track the mutational landscape resulting from AID modification or DNA double-strand break (DSB) formation and repair at sites known to be prone to DSBs. Implementation of this new assay showed that increased AID levels in immature B cells increases genome instability at loci linked to translocation formation. This included the CRLF2 locus that is often involved in chromosomal translocations associated with a subtype of acute lymphoblastic leukemia (ALL) that disproportionately affects Latin Americans (LAs). To support this LA-specific identification of AID mutation signatures, we characterized DNA from immature B cells isolated from the bone marrow of ALL patients. Our ability to detect and quantify these mutation signatures will potentiate future risk identification, early detection of cancers, and reduction of associated cancer health disparities.
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Canoy RJ, Shmakova A, Karpukhina A, Lomov N, Tiukacheva E, Kozhevnikova Y, André F, Germini D, Vassetzky Y. Specificity of cancer-related chromosomal translocations is linked to proximity after the DNA double-strand break and subsequent selection. NAR Cancer 2023; 5:zcad049. [PMID: 37750169 PMCID: PMC10518054 DOI: 10.1093/narcan/zcad049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/01/2023] [Accepted: 09/14/2023] [Indexed: 09/27/2023] Open
Abstract
Most cancer-related chromosomal translocations appear to be cell type specific. It is currently unknown why different chromosomal translocations occur in different cells. This can be due to either the occurrence of particular translocations in specific cell types or adaptive survival advantage conferred by translocations only in specific cells. We experimentally addressed this question by double-strand break (DSB) induction at MYC, IGH, AML and ETO loci in the same cell to generate chromosomal translocations in different cell lineages. Our results show that any translocation can potentially arise in any cell type. We have analyzed different factors that could affect the frequency of the translocations, and only the spatial proximity between gene loci after the DSB induction correlated with the resulting translocation frequency, supporting the 'breakage-first' model. Furthermore, upon long-term culture of cells with the generated chromosomal translocations, only oncogenic MYC-IGH and AML-ETO translocations persisted over a 60-day period. Overall, the results suggest that chromosomal translocation can be generated after DSB induction in any type of cell, but whether the cell with the translocation would persist in a cell population depends on the cell type-specific selective survival advantage that the chromosomal translocation confers to the cell.
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Affiliation(s)
- Reynand Jay Canoy
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 1000 Manila, The Philippines
| | - Anna Shmakova
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
- Laboratory of Molecular Endocrinology, Institute of Experimental Cardiology, Federal State Budgetary Organization ‘National Cardiology Research Center’ of the Ministry of Health of the Russian Federation, 127994 Moscow, Russia
- Koltzov Institute of Developmental Biology, 117334 Moscow, Russia
| | - Anna Karpukhina
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
- Koltzov Institute of Developmental Biology, 117334 Moscow, Russia
| | - Nikolai Lomov
- Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Eugenia Tiukacheva
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
- Koltzov Institute of Developmental Biology, 117334 Moscow, Russia
| | - Yana Kozhevnikova
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
| | - Franck André
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
| | - Diego Germini
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
| | - Yegor Vassetzky
- UMR 9018, CNRS, Univ. Paris-Sud, Université Paris Saclay, Institut Gustave Roussy, F-94805 Villejuif, France
- Koltzov Institute of Developmental Biology, 117334 Moscow, Russia
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5
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Georgakopoulos-Soares I, Victorino J, Parada GE, Agarwal V, Zhao J, Wong HY, Umar MI, Elor O, Muhwezi A, An JY, Sanders SJ, Kwok CK, Inoue F, Hemberg M, Ahituv N. High-throughput characterization of the role of non-B DNA motifs on promoter function. CELL GENOMICS 2022; 2:100111. [PMID: 35573091 PMCID: PMC9105345 DOI: 10.1016/j.xgen.2022.100111] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 10/21/2021] [Accepted: 02/18/2022] [Indexed: 12/24/2022]
Abstract
lternative DNA conformations, termed non-B DNA structures, can affect transcription, but the underlying mechanisms and their functional impact have not been systematically characterized. Here, we used computational genomic analyses coupled with massively parallel reporter assays (MPRAs) to show that certain non-B DNA structures have a substantial effect on gene expression. Genomic analyses found that non-B DNA structures at promoters harbor an excess of germline variants. Analysis of multiple MPRAs, including a promoter library specifically designed to perturb non-B DNA structures, functionally validated that Z-DNA can significantly affect promoter activity. We also observed that biophysical properties of non-B DNA motifs, such as the length of Z-DNA motifs and the orientation of G-quadruplex structures relative to transcriptional direction, have a significant effect on promoter activity. Combined, their higher mutation rate and functional effect on transcription implicate a subset of non-B DNA motifs as major drivers of human gene-expression-associated phenotypes.
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Affiliation(s)
- Ilias Georgakopoulos-Soares
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Jesus Victorino
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
| | - Guillermo E. Parada
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | | | - Jingjing Zhao
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Hei Yuen Wong
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Mubarak Ishaq Umar
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Orry Elor
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Allan Muhwezi
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK
| | - Joon-Yong An
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Stephan J. Sanders
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
| | - Fumitaka Inoue
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Martin Hemberg
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
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6
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Sterrenberg JN, Folkerts ML, Rangel V, Lee SE, Pannunzio NR. Diversity upon diversity: linking DNA double-strand break repair to blood cancer health disparities. Trends Cancer 2022; 8:328-343. [PMID: 35094960 PMCID: PMC9248772 DOI: 10.1016/j.trecan.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/20/2021] [Accepted: 01/03/2022] [Indexed: 10/19/2022]
Abstract
Chromosomal translocations arising from aberrant repair of multiple DNA double-strand breaks (DSBs) are a defining characteristic of many cancers. DSBs are an essential part of physiological processes in antibody-producing B cells. The B cell environment is poised to generate genome instability leading to translocations relevant to the pathology of blood cancers. These are a diverse set of cancers, but limited data from under-represented groups have pointed to health disparities associated with each. We focus on the DSBs that occur in developing B cells and propose the most likely mechanism behind the formation of translocations. We also highlight specific cancers in which these rearrangements occur and address the growing concern of health disparities associated with them.
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7
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Ramsden DA, Nussenzweig A. Mechanisms driving chromosomal translocations: lost in time and space. Oncogene 2021; 40:4263-4270. [PMID: 34103687 PMCID: PMC8238880 DOI: 10.1038/s41388-021-01856-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/07/2021] [Accepted: 05/21/2021] [Indexed: 02/05/2023]
Abstract
Translocations arise when an end of one chromosome break is mistakenly joined to an end from a different chromosome break. Since translocations can lead to developmental disease and cancer, it is important to understand the mechanisms leading to these chromosome rearrangements. We review how characteristics of the sources and the cellular responses to chromosome breaks contribute to the accumulation of multiple chromosome breaks at the same moment in time. We also discuss the important role for chromosome break location; how translocation potential is impacted by the location of chromosome breaks both within chromatin and within the nucleus, as well as the effect of altered mobility of chromosome breaks. A common theme in work addressing both temporal and spatial contributions to translocation is that there is no shortage of examples of factors that promote translocation in one context, but have no impact or the opposite impact in another. Accordingly, a clear message for future work on translocation mechanism is that unlike normal DNA metabolic pathways, it isn't easily modeled as a simple, linear pathway that is uniformly followed regardless of differing cellular contexts.
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Affiliation(s)
- Dale A. Ramsden
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Correspondence:
| | - Andre Nussenzweig
- Laboratory of Genome Integrity, National Institutes of Health, Bethesda, United States
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8
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Stewart JA, Schauer G, Bhagwat AS. Visualization of uracils created by APOBEC3A using UdgX shows colocalization with RPA at stalled replication forks. Nucleic Acids Res 2020; 48:e118. [PMID: 33074285 PMCID: PMC7672425 DOI: 10.1093/nar/gkaa845] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 12/19/2022] Open
Abstract
The AID/APOBEC enzymes deaminate cytosines in single-stranded DNA (ssDNA) and play key roles in innate and adaptive immunity. The resulting uracils cause mutations and strand breaks that inactivate viruses and diversify antibody repertoire. Mutational evidence suggests that two members of this family, APOBEC3A (A3A) and APOBEC3B, deaminate cytosines in the lagging-strand template during replication. To obtain direct evidence for the presence of these uracils, we engineered a protein that covalently links to DNA at uracils, UdgX, for mammalian expression and immunohistochemistry. We show that UdgX strongly prefers uracils in ssDNA over those in U•G or U:A pairs, and localizes to nuclei in a dispersed form. When A3A is expressed in these cells, UdgX tends to form foci. The treatment of cells with cisplatin, which blocks replication, causes a significant increase in UdgX foci. Furthermore, this protein- and hence the uracils created by A3A- colocalize with replication protein A (RPA), but not with A3A. Using purified proteins, we confirm that RPA inhibits A3A by binding ssDNA, but despite its overexpression following cisplatin treatment, RPA is unable to fully protect ssDNA created by cisplatin adducts. This suggests that cisplatin treatment of cells expressing APOBEC3A should cause accumulation of APOBEC signature mutations.
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Affiliation(s)
- Jessica A Stewart
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - Grant Schauer
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Ashok S Bhagwat
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.,Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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9
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Pannunzio NR, Lieber MR. Constitutively active Artemis nuclease recognizes structures containing single-stranded DNA configurations. DNA Repair (Amst) 2019; 83:102676. [PMID: 31377101 DOI: 10.1016/j.dnarep.2019.102676] [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: 02/12/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 01/03/2023]
Abstract
The Artemis nuclease recognizes and endonucleolytically cleaves at single-stranded to double-stranded DNA (ss/dsDNA) boundaries. It is also a key enzyme in the non-homologous end joining (NHEJ) DNA double-strand break repair pathway. Previously, a truncated form, Artemis-413, was developed that is constitutively active both in vitro and in vivo. Here, we use this constitutively active form of Artemis to detect DNA structures with ss/dsDNA boundaries that arise under topological stress. Topoisomerases prevent abnormal levels of torsional stress through modulation of positive and negative supercoiling. We show that overexpression of Artemis-413 in yeast cells carrying genetic mutations that ablate topoisomerase activity have an increased frequency of DNA double-strand breaks (DSBs). Based on the biochemical activity of Artemis, this suggests an increase in ss/dsDNA-containing structures upon increased torsional stress, with DSBs arising due to Artemis cutting at these ss/dsDNA structures. Camptothecin targets topoisomerase IB (Top1), and cells treated with camptothecin show increased DSBs. We find that expression of Artemis-413 in camptothecin-treated cells leads to a reduction in DSBs, the opposite of what we find with topoisomerase genetic mutations. This contrast between outcomes not only confirms that topoisomerase mutation and topoisomerase poisoning have distinct effects on cells, but also demonstrates the usefulness of Artemis-413 to study changes in DNA structure.
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Affiliation(s)
- Nicholas R Pannunzio
- Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Norris Comprehensive Cancer Center, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA.
| | - Michael R Lieber
- Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Norris Comprehensive Cancer Center, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089, USA.
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10
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Cancer mutational burden is shaped by G4 DNA, replication stress and mitochondrial dysfunction. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:47-61. [PMID: 30880007 DOI: 10.1016/j.pbiomolbio.2019.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/08/2019] [Accepted: 03/12/2019] [Indexed: 02/01/2023]
Abstract
A hallmark of cancer is genomic instability, which can enable cancer cells to evade therapeutic strategies. Here we employed a computational approach to uncover mechanisms underlying cancer mutational burden by focusing upon relationships between 1) translocation breakpoints and the thousands of G4 DNA-forming sequences within retrotransposons impacting transcription and exemplifying probable non-B DNA structures and 2) transcriptome profiling and cancer mutations. We determined the location and number of G4 DNA-forming sequences in the Genome Reference Consortium Human Build 38 and found a total of 358,605 covering ∼13.4 million bases. By analyzing >97,000 unique translocation breakpoints from the Catalogue Of Somatic Mutations In Cancer (COSMIC), we found that breakpoints are overrepresented at G4 DNA-forming sequences within hominid-specific SVA retrotransposons, and generally occur in tumors with mutations in tumor suppressor genes, such as TP53. Furthermore, correlation analyses between mRNA levels and exome mutational loads from The Cancer Genome Atlas (TCGA) encompassing >450,000 gene-mutation regressions revealed strong positive and negative associations, which depended upon tissue of origin. The strongest positive correlations originated from genes not listed as cancer genes in COSMIC; yet, these show strong predictive power for survival in most tumor types by Kaplan-Meier estimation. Thus, correlation analyses of DNA structure and gene expression with mutation loads complement and extend more traditional approaches to elucidate processes shaping genomic instability in cancer. The combined results point to G4 DNA, activation of cell cycle/DNA repair pathways, and mitochondrial dysfunction as three major factors driving the accumulation of somatic mutations in cancer cells.
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