1
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Liu Y, Cui K, Ma W. Gene mutation profiling in microsatellite instability colorectal cancer and its association with the efficacy of immunotherapy: A retrospective study. Cancer Med 2024; 13:e6910. [PMID: 38746969 PMCID: PMC11094515 DOI: 10.1002/cam4.6910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/29/2023] [Accepted: 12/25/2023] [Indexed: 05/18/2024] Open
Abstract
BACKGROUND Microsatellite instability-high (MSI-H) colorectal cancer (CRC) is known for its heightened responsiveness to immunotherapy. However, establishing robust predictive markers for immunotherapy efficacy remains imperative. This retrospective study aimed to elucidate the genetic landscape of MSI-H CRC and correlate these genetic alterations with immunotherapy outcomes in a cohort of 121 patients. METHODS We analyzed clinical and molecular data from 121 patients with MSI-H CRC. We conducted a thorough genetic analysis of MSI-H CRC patients, with a specific emphasis on the APC, TP53, RAS, and MMR genes. We further analyzed the relationship between gene mutations and immunotherapy efficacy. The primary endpoints analyzed were objective response rate (ORR) and progression-free survival (PFS). All statistical analysis was conducted using SPSS26.0 and R 4.2.0 software. RESULTS Our findings underscored the complexity of the genetic landscape in MSI-H CRC, shedding light on the intricate interplay of these genes in CRC development. Notably, mutations in MMR genes exhibited a distinctive pattern, providing insights into the underlying mechanisms of MSI-H. Furthermore, our results revealed correlations between specific genetic alterations and immunotherapy outcomes, with a particular focus on treatment response rates and progression-free survival. CONCLUSION This study represents a significant step toward unraveling the genetic nuances of MSI-H CRC. The distinctive pattern of MMR gene mutations not only adds depth to our understanding of MSI-H CRC but also hints at potential avenues for targeted therapies. This research sets the stage for future investigations aimed at refining therapeutic strategies and improving outcomes for patients with MSI-H CRC.
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Affiliation(s)
- Ying Liu
- Department of OncologyThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanPeople's Republic of China
| | - Kang Cui
- Department of OncologyThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanPeople's Republic of China
| | - Wang Ma
- Department of OncologyThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanPeople's Republic of China
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2
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Asami M, Lam BYH, Hoffmann M, Suzuki T, Lu X, Yoshida N, Ma MK, Rainbow K, Gužvić M, VerMilyea MD, Yeo GSH, Klein CA, Perry ACF. A program of successive gene expression in mouse one-cell embryos. Cell Rep 2023; 42:112023. [PMID: 36729835 DOI: 10.1016/j.celrep.2023.112023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/26/2022] [Accepted: 01/09/2023] [Indexed: 02/03/2023] Open
Abstract
At the moment of union in fertilization, sperm and oocyte are transcriptionally silent. The ensuing onset of embryonic transcription (embryonic genome activation [EGA]) is critical for development, yet its timing and profile remain elusive in any vertebrate species. We here dissect transcription during EGA by high-resolution single-cell RNA sequencing of precisely synchronized mouse one-cell embryos. This reveals a program of embryonic gene expression (immediate EGA [iEGA]) initiating within 4 h of fertilization. Expression during iEGA produces canonically spliced transcripts, occurs substantially from the maternal genome, and is mostly downregulated at the two-cell stage. Transcribed genes predict regulation by transcription factors (TFs) associated with cancer, including c-Myc. Blocking c-Myc or other predicted regulatory TF activities disrupts iEGA and induces acute developmental arrest. These findings illuminate intracellular mechanisms that regulate the onset of mammalian development and hold promise for the study of cancer.
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Affiliation(s)
- Maki Asami
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Brian Y H Lam
- Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Martin Hoffmann
- Project Group Personalized Tumor Therapy, Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Regensburg, Germany
| | - Toru Suzuki
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Xin Lu
- Experimental Medicine and Therapy Research, University of Regensburg, Regensburg, Germany
| | - Naoko Yoshida
- Department of Pathology, Kansai Medical University, Osaka 573-1010, Japan
| | - Marcella K Ma
- Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Kara Rainbow
- Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Miodrag Gužvić
- Experimental Medicine and Therapy Research, University of Regensburg, Regensburg, Germany
| | - Matthew D VerMilyea
- Embryology and Andrology Laboratories, Ovation Fertility Austin, Austin, TX 78731, USA
| | - Giles S H Yeo
- Medical Research Council (MRC) Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK.
| | - Christoph A Klein
- Project Group Personalized Tumor Therapy, Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Regensburg, Germany; Experimental Medicine and Therapy Research, University of Regensburg, Regensburg, Germany.
| | - Anthony C F Perry
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
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3
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Pei M, Dong A, Ma X, Li S, Guo Y, Li M, Wang Z, Wang H, Zhu L, Pan C, Wang Y. Identification of potential antigenic peptides of Brucella through proteome and peptidome. Vet Med Sci 2022; 9:523-534. [PMID: 36583994 PMCID: PMC9856995 DOI: 10.1002/vms3.1048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Brucellosis, caused by Brucella spp., is a major zoonotic public health threat. Although several Brucella vaccines have been demonstrated for use in animals, Brucella spp. can cause human infection and to date, there are no human-use vaccines licensed by any agency. Recently, methods in vaccine informatics have made major breakthroughs in peptide-based epitopes, opening up a new avenue of vaccine development. OBJECTIVES The purpose of this article was to identify potential antigenic peptides in Brucella by proteome and peptidome analyses. METHODS Mouse infection models were first established by injection with Brucella and spleen protein profiles were then analysed. Subsequently, the major histocompatibility complex class I or II (major histocompatibility complex [MHC]-I/II)-binding peptides in blood samples were collected by immunoprecipitation and peptides derived from Brucella proteins were identified through liquid chromatography-mass spectrometry (LC-MS/MS). These peptides were then evaluated in a variety of ways, such as in terms of conservation in Brucella and synchronicity in predicted peptides (similarity and coverage), which allowed us to more effectively measure their antigenic potential. RESULTS The expression of the inflammatory cytokines IL1B and IFN-γ was significantly altered in the spleen of infected mice and some Brucella proteins, such as Muri, AcpP and GroES, were also detected. Meanwhile, in blood, 35 peptides were identified and most showed high conservation, highlighting their potential as antigen epitopes for vaccine development. In particular, we identified four proteins containing both MHC-I- and MHC-II-binding peptides including AtpA, AtpD, DnaK and BAbS19_II02030. They were also compared with the predicted peptides to estimate their reliability. CONCLUSIONS The peptides we screened could bind to MHC molecules. After being stimulated with antigen T epitopes, Memory T cells can stimulate T cell activation and promote immune responses. Our results indicated that the peptides we identified may be good candidate targets for the design of subunit vaccines and these results pave the way for the study of safer vaccines against Brucella.
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Affiliation(s)
- Meijuan Pei
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalThe Training Site for Postgraduate of Jinzhou Medical UniversityBeijingChina,State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Ao Dong
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Xueping Ma
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalBeijingChina
| | - Shulei Li
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalThe Training Site for Postgraduate of Jinzhou Medical UniversityBeijingChina,State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Yan Guo
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Menglan Li
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalBeijingChina
| | - Zhenghui Wang
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalBeijingChina
| | - Hengliang Wang
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Li Zhu
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Chao Pan
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of BiotechnologyBeijingChina
| | - Yufei Wang
- Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalThe Training Site for Postgraduate of Jinzhou Medical UniversityBeijingChina,Department of Clinical LaboratoryThe Third Medical Centre of Chinese PLA General HospitalBeijingChina
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4
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Treas J, Roy P, Singh KP. Chronic coexposure to arsenic and estrogen potentiates genotoxic estrogen metabolic pathway and hypermethylation of DNA glycosylase MBD4 in human prostate epithelial cells. Prostate 2022; 82:1273-1283. [PMID: 35747940 DOI: 10.1002/pros.24401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/14/2022] [Accepted: 06/01/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND Previously we reported that arsenic and estrogen cause synergistic effects in the neoplastic transformation of human prostate epithelial cells. In addition to receptor-mediated pathways, DNA-reactive estrogen metabolites have also been shown to play a critical role in mutagenicity and carcinogenicity. Both estrogen and arsenic are known prostate carcinogens, however, the effect of coexposure to these two chemicals on genes involved in estrogen metabolism is not known. Therefore, the objective of this study was to evaluate the role of arsenic and estrogen coexposure on the expression of estrogen receptors and estrogen metabolism-associated genes. Earlier, we also reported the synergistic effect of arsenic and estrogen on decreased expression of MBD4 genes that play an important role in DNA repair through its DNA glycosylase activity. To further understand the mechanism, the promoter methylation of this gene was also analyzed. METHODS Total RNA and protein were isolated from RWPE-1 human prostate epithelial cells that were coexposed to arsenic and estrogen for a chronic duration (6 months). The expression of estrogen receptors, estrogen metabolism associated phase I genes (CYP 1A1, 1A2, 3A4, and 1B1) and phase II gene catechol-O-methyltransferase (COMT), as well as antioxidant MnSOD, were analyzed either at the RNA level by quantitative reverse transcriptase-polymerase chain reaction or at the protein level by western blot. Promoter methylation of MBD4 was analyzed by pyrosequencing. RESULTS Expression of MnSOD and phase I genes that convert E2 into genotoxic metabolites 2-OH-E2 and 4-OH-E2 were significantly increased, whereas the expression of phase II gene COMT that detoxifies estrogen metabolites was significantly decreased in arsenic and estrogen coexposed cells. MBD4 promoter was hypermethylated in arsenic and estrogen coexposed cells. Coexposure to arsenic and estrogen has synergistic effects on the expression of these genes as well as in MBD4 promoter hypermethylation. CONCLUSIONS These novel findings suggest that coexposure to arsenic and estrogen acts synergistically in the activation of not only the estrogen receptors but also the genes associated with genotoxic estrogen metabolism and epigenetic inactivation of DNA glycosylase MBD4. Together, these genetic and epigenetic aberrations provide the molecular basis for the potentiation of carcinogenicity of arsenic and estrogen coexposure in prostate epithelial cells.
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Affiliation(s)
- Justin Treas
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Priti Roy
- Department of Internal Medicine, University of California San Francisco, San Francisco, California, USA
| | - Kamaleshwar P Singh
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, Texas, USA
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5
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Meas R, Nititham J, Taylor KE, Maher S, Clairmont K, Carufe KEW, Kashgarian M, Nottoli T, Cheong A, Nagel ZD, Gaffney PM, Criswell LA, Sweasy JB. A Human MSH6 Germline Variant Associated With Systemic Lupus Erythematosus Induces Lupus-like Disease in Mice. ACR Open Rheumatol 2022; 4:760-770. [PMID: 35708944 PMCID: PMC9469486 DOI: 10.1002/acr2.11471] [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: 06/05/2021] [Revised: 02/09/2022] [Accepted: 02/22/2022] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE To determine if single-nucleotide polymorphisms (SNPs) in DNA repair genes are enriched in individuals with systemic lupus erythematosus (SLE) and if they are sufficient to confer a disease phenotype in a mouse model. METHODS Human exome chip data of 2499 patients with SLE and 1230 healthy controls were analyzed to determine if variants in 10 different mismatch repair genes (MSH4, EXO1, MSH2, MSH6, MLH1, MSH3, POLH, PMS2, ML3, and APEX2) were enriched in individuals with SLE. A mouse model of the MSH6 SNP, which was found to be enriched in individuals with SLE, was created using CRISPR/Cas9 gene targeting. Wildtype mice and mice heterozygous and homozygous for the MSH6 variant were then monitored for 2 years for the development of autoimmune phenotypes, including the presence of high levels of antinuclear antibodies (ANA). Additionally, somatic hypermutation frequencies and spectra of the intronic region downstream of the VH J558-rearranged JH4 immunoglobulin gene was characterized from Peyer's patches. RESULTS Based on the human exome chip data, the MSH6 variant (rs63750897, p.Ser503Cys) is enriched among patients with SLE versus controls after we corrected for ancestry (odds ratio = 8.39, P = 0.0398). Mice homozygous for the MSH6 variant (Msh6S502C/S502C ) harbor significantly increased levels of ANA. Additionally, the Msh6S502C/S502C mice display a significant increase in the infiltration of CD68+ cells (a marker for monocytes and macrophages) into the lung alveolar space as well as apoptotic cells. Furthermore, characterization of somatic hypermutation in these mice reveals an increase in the DNA polymerase η mutational signature. CONCLUSION An MSH6 mutation that is enriched in humans diagnosed with lupus was identified. Mice harboring this Msh6 mutation develop increased autoantibodies and an inflammatory lung disease. These results suggest that the human MSH6 variant is linked to the development of SLE.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Ana Cheong
- Harvard School of Public HealthBostonMassachusettsUSA
| | | | | | - Lindsey A. Criswell
- National Institute of Arthritis and Musculoskeletal and Skin DiseasesBethesdaMarylandUSA
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6
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Wen J, Wang Y, Yuan M, Huang Z, Zou Q, Pu Y, Zhao B, Cai Z. Role of mismatch repair in aging. Int J Biol Sci 2021; 17:3923-3935. [PMID: 34671209 PMCID: PMC8495402 DOI: 10.7150/ijbs.64953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/07/2021] [Indexed: 01/10/2023] Open
Abstract
A common feature of aging is the accumulation of genetic damage throughout life. DNA damage can lead to genomic instability. Many diseases associated with premature aging are a result of increased accumulation of DNA damage. In order to minimize these damages, organisms have evolved a complex network of DNA repair mechanisms, including mismatch repair (MMR). In this review, we detail the effects of MMR on genomic instability and its role in aging emphasizing on the association between MMR and the other hallmarks of aging, serving to drive or amplify these mechanisms. These hallmarks include telomere attrition, epigenetic alterations, mitochondrial dysfunction, altered nutrient sensing and cell senescence. The close relationship between MMR and these markers may provide prevention and treatment strategies, to reduce the incidence of age-related diseases and promote the healthy aging of human beings.
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Affiliation(s)
- Jie Wen
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China.,Department and Institute of Neurology, Guangdong Medical University, Guangdong, 524001, China.,Guangdong Key Laboratory of aging related cardio cerebral diseases, Guangdong, 524001, China
| | - Yangyang Wang
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
| | - Minghao Yuan
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
| | - Zhenting Huang
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
| | - Qian Zou
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
| | - Yinshuang Pu
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
| | - Bin Zhao
- Department and Institute of Neurology, Guangdong Medical University, Guangdong, 524001, China.,Guangdong Key Laboratory of aging related cardio cerebral diseases, Guangdong, 524001, China
| | - Zhiyou Cai
- Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, China
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7
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Detection of Genomic Uracil Patterns. Int J Mol Sci 2021; 22:ijms22083902. [PMID: 33918885 PMCID: PMC8070346 DOI: 10.3390/ijms22083902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/28/2021] [Accepted: 04/05/2021] [Indexed: 01/06/2023] Open
Abstract
The appearance of uracil in the deoxyuridine moiety of DNA is among the most frequently occurring genomic modifications. Three different routes can result in genomic uracil, two of which do not require specific enzymes: spontaneous cytosine deamination due to the inherent chemical reactivity of living cells, and thymine-replacing incorporation upon nucleotide pool imbalances. There is also an enzymatic pathway of cytosine deamination with multiple DNA (cytosine) deaminases involved in this process. In order to describe potential roles of genomic uracil, it is of key importance to utilize efficient uracil-DNA detection methods. In this review, we provide a comprehensive and critical assessment of currently available uracil detection methods with special focus on genome-wide mapping solutions. Recent developments in PCR-based and in situ detection as well as the quantitation of genomic uracil are also discussed.
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8
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Dhakras P, Uboha N, Horner V, Reinig E, Matkowskyj KA. Gastrointestinal cancers: current biomarkers in esophageal and gastric adenocarcinoma. Transl Gastroenterol Hepatol 2020; 5:55. [PMID: 33073050 DOI: 10.21037/tgh.2020.01.08] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/15/2020] [Indexed: 12/29/2022] Open
Abstract
Esophageal and gastric adenocarcinomas are frequently diagnosed at an advanced stage and have a dismal prognosis. Even in patients with potentially curative cancer, nearly 50% will develop recurrent disease despite aggressive treatments. A number of biomarkers currently guide treatment decisions for patients with esophageal and gastric adenocarcinoma and include human epidermal growth factor receptor 2 (HER2) amplification, mismatch repair deficiency/microsatellite instability (dMMR/MSI-H) and program death-ligand 1 (PD-L1) expression. This review will focus on the function, testing and FDA-approved targeted therapies for HER2, dMMR/MSI-H and PD-L1. In addition, a number of novel targets in esophageal and gastric cancer are being studied in clinical trials. Neurotrophic-tropomyosin receptor kinase (NTRK), claudin-18 (CLDN18)/Rho GTPase activating protein 26 (ARHGAP26) gene fusion, fibroblast growth factor receptor (FGFR), lymphocyte-activation gene 3 (LAG3) and T cell immunoglobulin and mucin-domain containing-3 (TIM3) will be briefly reviewed. Despite several biomarkers used in the selection of treatment therapies, treatment outcomes remain poor. Future research efforts will focus on the identification of new biomarkers, moving existing biomarkers into earlier lines of therapy, and evaluating new combinations of existing biomarkers and therapies.
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Affiliation(s)
- Purabi Dhakras
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, USA
| | - Nataliya Uboha
- Division of Hematology, Medical Oncology and Palliative Care, Department of Medicine, University of Wisconsin, Madison, WI, USA.,UW Carbone Cancer Center, Madison, WI, USA.,William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Vanessa Horner
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, USA.,Wisconsin State Lab of Hygiene, Madison, WI, USA
| | - Erica Reinig
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, USA
| | - Kristina A Matkowskyj
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, USA.,UW Carbone Cancer Center, Madison, WI, USA.,William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
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Piekna-Przybylska D, Bambara RA, Maggirwar SB, Dewhurst S. G-quadruplex ligands targeting telomeres do not inhibit HIV promoter activity and cooperate with latency reversing agents in killing latently infected cells. Cell Cycle 2020; 19:2298-2313. [PMID: 32807015 DOI: 10.1080/15384101.2020.1796268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Altered telomere maintenance mechanism (TMM) is linked to increased DNA damage at telomeres and telomere uncapping. We previously showed that HIV-1 latent cells have altered TMM and are susceptible to ligands that target G-quadruplexes (G4) at telomeres. Susceptibility of latent cells to telomere targeting could potentially be used to support approaches to eradicate HIV reservoirs. However, G4 ligands also target G-quadruplexes in promoters blocking gene transcription. Since HIV promoter sequence can form G-quadruplexes, we investigated whether G4 ligands interfere with HIV-1 promoter activity and virus reactivation from latency, and whether telomere targeting could be combined with latency reversing agents (LRAs) to promote elimination of HIV reservoirs. Our results indicate that Sp1 binding region in HIV-1 promoter can adopt G4 structures in duplex DNA, and that in vitro binding of Sp1 to G-quadruplex is blocked by G4 ligand, suggesting that agents targeting telomeres interfere with virus reactivation. However, our studies show that G4 agents do not affect HIV-1 promoter activity in cell culture, and do not interfere with latency reversal. Importantly, primary memory CD4 + T cells infected with latent HIV-1 are more susceptible to combined treatment with LRAs and G4 ligands, indicating that drugs targeting TMM may enhance killing of HIV reservoirs. Using a cell-based DNA repair assay, we also found that HIV-1 infected cells have reduced efficiency of DNA mismatch repair (MMR), and base excision repair (BER), suggesting that altered TMM in latently infected cells could be associated with accumulation of DNA damage at telomeres and changes in telomeric caps.
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Affiliation(s)
- Dorota Piekna-Przybylska
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
| | - Robert A Bambara
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
| | - Sanjay B Maggirwar
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University , Washington, DC, USA
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
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10
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Costello R, Cantillo JF, Kenter AL. Chicken MBD4 Regulates Immunoglobulin Diversification by Somatic Hypermutation. Front Immunol 2019; 10:2540. [PMID: 31736964 PMCID: PMC6838969 DOI: 10.3389/fimmu.2019.02540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/14/2019] [Indexed: 01/21/2023] Open
Abstract
Immunoglobulin (Ig) diversification occurs via somatic hypermutation (SHM) and class switch recombination (CSR), and is initiated by activation-induced deaminase (AID), which converts cytosine to uracil. Variable (V) region genes undergo SHM to create amino acid substitutions that produce antibodies with higher affinity for antigen. The conversion of cytosine to uracil in DNA promotes mutagenesis. Two distinct DNA repair mechanisms regulate uracil processing in Ig genes. The first involves base removal by the uracil DNA glycosylase (UNG), and the second detects uracil via the mismatch repair (MMR) complex. Methyl binding domain protein 4 (MBD4) is a uracil glycosylase and an intriguing candidate for involvement in somatic hypermutation because of its interaction with the MMR MutL homolog 1 (MLH1). We found that the DNA uracil glycosylase domain of MBD4 is highly conserved among mammals, birds, shark, and insects. Conservation of the human and chicken MBD4 uracil glycosylase domain structure is striking. Here we examined the function of MBD4 in chicken DT40 B cells which undergo constitutive SHM. We constructed structural variants of MBD4 DT40 cells using CRISPR/Cas9 genome editing. Disruption of the MBD4 uracil glycosylase catalytic region increased SHM frequency in IgM loss assays. We propose that MBD4 plays a role in SHM.
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Affiliation(s)
- Ryan Costello
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
| | - Jose F Cantillo
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
| | - Amy L Kenter
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
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11
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Tamura K, Kaneda M, Futagawa M, Takeshita M, Kim S, Nakama M, Kawashita N, Tatsumi-Miyajima J. Genetic and genomic basis of the mismatch repair system involved in Lynch syndrome. Int J Clin Oncol 2019; 24:999-1011. [PMID: 31273487 DOI: 10.1007/s10147-019-01494-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 06/17/2019] [Indexed: 12/11/2022]
Abstract
Lynch syndrome is a cancer-predisposing syndrome inherited in an autosomal-dominant manner, wherein colon cancer and endometrial cancer develop frequently in the family, it results from a loss-of-function mutation in one of four different genes (MLH1, MSH2, MSH6, and PMS2) encoding mismatch repair proteins. Being located immediately upstream of the MSH2 gene, EPCAM abnormalities can affect MSH2 and cause Lynch syndrome. Mismatch repair proteins are involved in repairing of incorrect pairing (point mutations and deletion/insertion of simple repetitive sequences, so-called microsatellites) that can arise during DNA replication. MSH2 forms heterodimers with MSH6 or MSH3 (MutSα, MutSβ, respectively) and is involved in mismatch-pair recognition and initiation of repair. MLH1 forms a complex with PMS2, and functions as an endonuclease. If the mismatch repair system is thoroughly working, genome integrity is maintained completely. Lynch syndrome is a state of mismatch repair deficiency due to a monoallelic abnormality of any mismatch repair genes. The phenotype indicating the mismatch repair deficiency can be frequently shown as a microsatellite instability in tumors. Children with germline biallelic mismatch repair gene abnormalities were reported to develop conditions such as gastrointestinal polyposis, colorectal cancer, brain cancer, leukemia, etc., and so on, demonstrating the need to respond with new concepts in genetic counseling. In promoting cancer genome medicine in a new era, such as by utilizing immune checkpoints, it is important to understand the genetic and genomic molecular background, including the status of mismatch repair deficiency.
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Affiliation(s)
- Kazuo Tamura
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan.
| | - Motohide Kaneda
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
| | - Mashu Futagawa
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
| | - Miho Takeshita
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
| | - Sanghyuk Kim
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
| | - Mina Nakama
- Division of Clinical Genetics, Gifu University Hospital, Gifu, Japan
| | - Norihito Kawashita
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
| | - Junko Tatsumi-Miyajima
- Division of Medical Genetics, Master of Science, Graduate School of Science and Engineering Research, Kindai University, Higashiosaka, Japan
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12
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Meier B, Volkova NV, Hong Y, Schofield P, Campbell PJ, Gerstung M, Gartner A. Mutational signatures of DNA mismatch repair deficiency in C. elegans and human cancers. Genome Res 2018; 28:666-675. [PMID: 29636374 PMCID: PMC5932607 DOI: 10.1101/gr.226845.117] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 01/02/2018] [Indexed: 12/18/2022]
Abstract
Throughout their lifetime, cells are subject to extrinsic and intrinsic mutational processes leaving behind characteristic signatures in the genome. DNA mismatch repair (MMR) deficiency leads to hypermutation and is found in different cancer types. Although it is possible to associate mutational signatures extracted from human cancers with possible mutational processes, the exact causation is often unknown. Here, we use C. elegans genome sequencing of pms-2 and mlh-1 knockouts to reveal the mutational patterns linked to C. elegans MMR deficiency and their dependency on endogenous replication errors and errors caused by deletion of the polymerase ε subunit pole-4 Signature extraction from 215 human colorectal and 289 gastric adenocarcinomas revealed three MMR-associated signatures, one of which closely resembles the C. elegans MMR spectrum and strongly discriminates microsatellite stable and unstable tumors (AUC = 98%). A characteristic difference between human and C. elegans MMR deficiency is the lack of elevated levels of NCG > NTG mutations in C. elegans, likely caused by the absence of cytosine (CpG) methylation in worms. The other two human MMR signatures may reflect the interaction between MMR deficiency and other mutagenic processes, but their exact cause remains unknown. In summary, combining information from genetically defined models and cancer samples allows for better aligning mutational signatures to causal mutagenic processes.
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Affiliation(s)
- Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Nadezda V Volkova
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton CB10 1SD, United Kingdom
| | - Ye Hong
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Pieta Schofield
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, United Kingdom
- Division of Computational Biology, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Peter J Campbell
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge CB2 0XY, United Kingdom
- Department of Haematology, Addenbrooke's Hospital, Cambridge CB2 0XY, United Kingdom
| | - Moritz Gerstung
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton CB10 1SD, United Kingdom
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, United Kingdom
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Liu X, Liu S, Lei J, Zou L, Xiao L, Zhang G. Methylation and expression of mismatch repair gene human mutS homolog 2 in myelodysplastic syndromes. Exp Ther Med 2018; 15:500-505. [PMID: 29387203 DOI: 10.3892/etm.2017.5402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/26/2017] [Indexed: 11/06/2022] Open
Abstract
As a highly heterogeneous disease, the pathogenesis of myelodysplastic syndrome (MDS) has not been well defined. In the present study, human mutS homolog 2 (hMSH2) promoter methylation was detected with methylation-specific polymerase chain reaction (PCR). The function of hMSH2 was analyzed by microsatellite instability (MSI) detection of BAT-26, and hMSH2 expression was evaluated using reverse transcription-quantitative PCR in 60 patients with MDS. The results revealed methylation of the hMSH2 promoter in 18 patients with MDS who have an overall prevalence of 30% (95% confidence interval, 18.4-41.6%). Among the patients with hMSH2 methylation, 2 patients exhibited MSI. It was demonstrated that hMSH2 promoter methylation was increased in MDS with an increase in Revised International Prognostic Scoring System (IPSS-R) risk, and patients with higher hMSH2 promoter methylation had shorter overall survival by Kaplan-Meier analysis (P=0.011). In addition, it was also observed that decreased hMSH2 mRNA expression was associated with high IPSS-R risk group (high/very high vs. intermediate, P=0.003), and hMSH2 mRNA expression in CD34 positive bone marrow cells was lower compared with that in CD34 negative cells of patients with MDS (P=0.029). Methylation of hMSH2 may be valuable for prognostic evaluation and progression prediction of MDS. Furthermore, hMSH2 may serve a key function in the pathogenesis and prognosis of MDS.
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Affiliation(s)
- Xiaoliu Liu
- Department of Hematology, The Affiliated Changsha Hospital, Hunan Normal University, Changsha, Hunan 410006, P.R. China
| | - Sufang Liu
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Jian Lei
- Department of Pathology, The Affiliated Tumor Hospital, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, P.R. China
| | - Lixin Zou
- Department of Hematology, The Affiliated Changsha Hospital, Hunan Normal University, Changsha, Hunan 410006, P.R. China
| | - Le Xiao
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Guangsen Zhang
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
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14
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Edwards Y. An Msh3 ATPase domain mutation has no effect on MMR function. BMC Res Notes 2017; 10:616. [PMID: 29178930 PMCID: PMC5702223 DOI: 10.1186/s13104-017-2939-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 11/15/2017] [Indexed: 11/10/2022] Open
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15
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Jahid S, Sun J, Gelincik O, Blecua P, Edelmann W, Kucherlapati R, Zhou K, Jasin M, Gümüş ZH, Lipkin SM. Inhibition of colorectal cancer genomic copy number alterations and chromosomal fragile site tumor suppressor FHIT and WWOX deletions by DNA mismatch repair. Oncotarget 2017; 8:71574-71586. [PMID: 29069730 PMCID: PMC5641073 DOI: 10.18632/oncotarget.17776] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/24/2017] [Indexed: 01/15/2023] Open
Abstract
Homologous recombination (HR) enables precise DNA repair after DNA double strand breaks (DSBs) using identical sequence templates, whereas homeologous recombination (HeR) uses only partially homologous sequences. Homeologous recombination introduces mutations through gene conversion and genomic deletions through single-strand annealing (SSA). DNA mismatch repair (MMR) inhibits HeR, but the roles of mammalian MMR MutL homologues (MLH1, PMS2 and MLH3) proteins in HeR suppression are poorly characterized. Here, we demonstrate that mouse embryonic fibroblasts (MEFs) carrying Mlh1, Pms2, and Mlh3 mutations have higher HeR rates, by using 7,863 uniquely mapping paired direct repeat sequences (DRs) in the mouse genome as endogenous gene conversion and SSA reporters. Additionally, when DSBs are induced by gamma-radiation, Mlh1, Pms2 and Mlh3 mutant MEFs have higher DR copy number alterations (CNAs), including DR CNA hotspots previously identified in mouse MMR-deficient colorectal cancer (dMMR CRC). Analysis of The Cancer Genome Atlas CRC data revealed that dMMR CRCs have higher genome-wide DR HeR rates than MMR proficient CRCs, and that dMMR CRCs have deletion hotspots in tumor suppressors FHIT/WWOX at chromosomal fragile sites FRA3B and FRA16D (which have elevated DSB rates) flanked by paired homologous DRs and inverted repeats (IR). Overall, these data provide novel insights into the MMR-dependent HeR inhibition mechanism and its role in tumor suppression.
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Affiliation(s)
- Sohail Jahid
- Departments of Medicine and Genetic Medicine, Weill Cornell Medicine, 10021, NY, USA
| | - Jian Sun
- Departments of Medicine and Genetic Medicine, Weill Cornell Medicine, 10021, NY, USA
| | - Ozkan Gelincik
- Departments of Medicine and Genetic Medicine, Weill Cornell Medicine, 10021, NY, USA
| | - Pedro Blecua
- Division of Clinical Genetics, Memorial Sloan Kettering Cancer Center, 10065, NY, USA
| | - Winfried Edelmann
- Department of Cell Biology and Department of Genetics, Albert Einstein College of Medicine of Yeshiva University, 10461, NY, USA
| | - Raju Kucherlapati
- Department of Genetics, Harvard Medical School, 02115, Boston, MA, USA
| | - Kathy Zhou
- Department of Biostatistics and Epidemiology, Weill Cornell Medical College, 10021, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, 10065, NY, USA
| | - Zeynep H Gümüş
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 10029, NY, USA.,Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, 10029, NY, USA
| | - Steven M Lipkin
- Departments of Medicine and Genetic Medicine, Weill Cornell Medicine, 10021, NY, USA
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16
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MBD4 Facilitates Immunoglobulin Class Switch Recombination. Mol Cell Biol 2017; 37:MCB.00316-16. [PMID: 27777312 DOI: 10.1128/mcb.00316-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/30/2016] [Indexed: 01/02/2023] Open
Abstract
Immunoglobulin heavy chain class switch recombination (CSR) requires targeted formation of DNA double-strand breaks (DSBs) in repetitive switch region elements followed by ligation between distal breaks. The introduction of DSBs is initiated by activation-induced cytidine deaminase (AID) and requires base excision repair (BER) and mismatch repair (MMR). The BER enzyme methyl-CpG binding domain protein 4 (MBD4) has been linked to the MMR pathway through its interaction with MutL homologue 1 (MLH1). We find that when Mbd4 exons 6 to 8 are deleted in a switching B cell line, DSB formation is severely reduced and CSR frequency is impaired. Impaired CSR can be rescued by ectopic expression of Mbd4 Mbd4 deficiency yields a deficit in DNA end processing similar to that found in MutS homologue 2 (Msh2)- and Mlh1-deficient B cells. We demonstrate that microhomology-rich S-S junctions are enriched in cells in which Mbd4 is deleted. Our studies suggest that Mbd4 is a component of MMR-directed DNA end processing.
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17
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Bishak YK, Payahoo L, Osatdrahimi A, Nourazarian A. Mechanisms of Cadmium Carcinogenicity in the Gastrointestinal Tract. Asian Pac J Cancer Prev 2015; 16:9-21. [DOI: 10.7314/apjcp.2015.16.1.9] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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18
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Godwin RC, Melvin R, Salsbury FR. Molecular Dynamics Simulations and Computer-Aided Drug Discovery. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2015. [DOI: 10.1007/7653_2015_41] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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19
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Perevozchikova SA, Trikin RM, Heinze RJ, Romanova EA, Oretskaya TS, Friedhoff P, Kubareva EA. Is thymidine glycol containing DNA a substrate of E. coli DNA mismatch repair system? PLoS One 2014; 9:e104963. [PMID: 25133614 PMCID: PMC4136841 DOI: 10.1371/journal.pone.0104963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/15/2014] [Indexed: 11/18/2022] Open
Abstract
The DNA mismatch repair (MMR) system plays a crucial role in the prevention of replication errors and in the correction of some oxidative damages of DNA bases. In the present work the most abundant oxidized pyrimidine lesion, 5,6-dihydro-5,6-dihydroxythymidine (thymidine glycol, Tg) was tested for being recognized and processed by the E. coli MMR system, namely complex of MutS, MutL and MutH proteins. In a partially reconstituted MMR system with MutS-MutL-MutH proteins, G/Tg and A/Tg containing plasmids failed to provoke the incision of DNA. Tg residue in the 30-mer DNA duplex destabilized double helix due to stacking disruption with neighboring bases. However, such local structural changes are not important for E. coli MMR system to recognize this lesion. A lack of repair of Tg containing DNA could be due to a failure of MutS (a first acting protein of MMR system) to interact with modified DNA in a proper way. It was shown that Tg in DNA does not affect on ATPase activity of MutS. On the other hand, MutS binding affinities to DNA containing Tg in G/Tg and A/Tg pairs are lower than to DNA with a G/T mismatch and similar to canonical DNA. Peculiarities of MutS interaction with DNA was monitored by Förster resonance energy transfer (FRET) and fluorescence anisotropy. Binding of MutS to Tg containing DNAs did not result in the formation of characteristic DNA kink. Nevertheless, MutS homodimer orientation on Tg-DNA is similar to that in the case of G/T-DNA. In contrast to G/T-DNA, neither G/Tg- nor A/Tg-DNA was able to stimulate ADP release from MutS better than canonical DNA. Thus, Tg residue in DNA is unlikely to be recognized or processed by the E. coli MMR system. Probably, the MutS transformation to active “sliding clamp” conformation on Tg-DNA is problematic.
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Affiliation(s)
- Svetlana A. Perevozchikova
- Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Roman M. Trikin
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Roger J. Heinze
- Institute for Biochemistry, Justus Liebig University, Giessen, Germany
| | - Elena A. Romanova
- Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatiana S. Oretskaya
- Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Peter Friedhoff
- Institute for Biochemistry, Justus Liebig University, Giessen, Germany
| | - Elena A. Kubareva
- Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
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20
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de Oliveira AHS, da Silva AE, de Oliveira IM, Henriques JAP, Agnez-Lima LF. MutY-glycosylase: an overview on mutagenesis and activities beyond the GO system. Mutat Res 2014; 769:119-31. [PMID: 25771731 DOI: 10.1016/j.mrfmmm.2014.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/28/2014] [Accepted: 08/04/2014] [Indexed: 02/06/2023]
Abstract
MutY is a glycosylase known for its role in DNA base excision repair (BER). It is critically important in the prevention of DNA mutations derived from 7,8-dihydro-8-oxoguanine (8-oxoG), which are the major lesions resulting from guanine oxidation. MutY has been described as a DNA repair enzyme in the GO system responsible for removing adenine residues misincorporated in 8-oxoG:A mispairs, avoiding G:C to T:A mutations. Further studies have shown that this enzyme binds to other mispairs, interacts with several enzymes, avoids different transversions/transitions in DNA, and is involved in different repair pathways. Additional activities have been reported for MutY, such as the repair of replication errors in newly synthesized DNA strands through its glycosylase activity. Moreover, MutY is a highly conserved enzyme present in several prokaryotic and eukaryotic organisms. MutY defects are associated with a hereditary colorectal cancer syndrome termed MUTYH-associated polyposis (MAP). Here, we have reviewed the roles of MutY in the repair of mispaired bases in DNA as well as its activities beyond the GO system.
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Affiliation(s)
- Ana Helena Sales de Oliveira
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil; Departamento de Biofísica e Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Acarízia Eduardo da Silva
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Iuri Marques de Oliveira
- Departamento de Biofísica e Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - João Antônio Pegas Henriques
- Departamento de Biofísica e Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto de Biotecnologia, Departamento de Ciências Biomédicas, Universidade de Caxias do Sul (UCS), Caxias do Sul, RS, Brazil
| | - Lucymara Fassarella Agnez-Lima
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
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21
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Histone deacetylase SIRT1 modulates and deacetylates DNA base excision repair enzyme thymine DNA glycosylase. Biochem J 2013; 456:89-98. [PMID: 23952905 DOI: 10.1042/bj20130670] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
TDG (thymine DNA glycosylase) is an essential multifunctional enzyme involved in DNA base excision repair, DNA demethylation and transcription regulation. TDG is the predominant enzyme that removes thymine from T/G mispair, which arises due to deamination of 5-methyl-cytosine at the CpG dinucleotide, thereby preventing C to T mutations. SIRT1 is a member of class III NAD+-dependent histone/protein deacetylases. In the present study, we demonstrate that SIRT1 interacts with residues 67-110 of hTDG (human TDG). In addition, SIRT1 enhances TDG glycosylase activity and deacetylates acetylated TDG. TDG acetylation weakens its interaction with SIRT1. Although acetylated TDG has reduced glycosylase activity towards T/G, 5-formylcytosine/G and 5-carboxylcytosine/G, it has a stronger activity towards a 5-fluorouracil/G substrate as compared with unmodified TDG. SIRT1 weakly stimulates acetylated hTDG activity towards T/G, 5-formylcytosine/G and 5-carboxylcytosine/G as compared with control hTDG. Sirt1-knockout mouse embryonic fibroblast cells have higher levels of TDG expression and acetylation. The physical and functional interactions between SIRT1 and TDG may mediate DNA repair, gene expression and FU (5-fluorouracil)-mediated cytotoxicity.
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22
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Treas J, Tyagi T, Singh KP. Chronic exposure to arsenic, estrogen, and their combination causes increased growth and transformation in human prostate epithelial cells potentially by hypermethylation-mediated silencing of MLH1. Prostate 2013; 73:1660-72. [PMID: 23804311 DOI: 10.1002/pros.22701] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 05/29/2013] [Indexed: 11/07/2022]
Abstract
BACKGROUND Chronic exposure to arsenic and estrogen is associated with risk of prostate cancer, but their mechanism is not fully understood. Additionally, the carcinogenic effects of their co-exposure are not known. Therefore, the objective of this study was to evaluate the effects of chronic exposure to arsenic, estrogen, and their combination, on cell growth and transformation, and identify the mechanism behind these effects. METHODS RWPE-1 human prostate epithelial cells were chronically exposed to arsenic and estrogen alone and in combination. Cell growth was measured by cell count and cell cycle, whereas cell transformation was evaluated by colony formation assay. Gene expression was measured by quantitative real-time PCR and confirmed at protein level by Western blot analysis. MLH1 promoter methylation was determined by pyrosequencing method. RESULTS Exposure to arsenic, estrogen, and their combinations increases cell growth and transformation in RWPE-1 cells. Increased expression of Cyclin D1 and Bcl2, whereas decreased expression of mismatch repair genes MSH4, MSH6, and MLH1 was also observed. Hypermethylation of MLH1 promoter further suggested the epigenetic inactivation of MLH1 expression in arsenic and estrogen treated cells. Arsenic and estrogen combination caused greater changes than their individual treatments. CONCLUSIONS Findings of this study for the first time suggest that arsenic and estrogen exposures cause increased cell growth and survival potentially through epigenetic inactivation of MLH1 resulting in decreased MLH1-mediated apoptotic response, and consequently increased cellular transformation.
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Affiliation(s)
- Justin Treas
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, Texas
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23
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Grigera F, Bellacosa A, Kenter AL. Complex relationship between mismatch repair proteins and MBD4 during immunoglobulin class switch recombination. PLoS One 2013; 8:e78370. [PMID: 24205214 PMCID: PMC3812156 DOI: 10.1371/journal.pone.0078370] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
Mismatch repair (MMR) safeguards against genomic instability and is required for efficient Ig class switch recombination (CSR). Methyl CpG binding domain protein 4 (MBD4) binds to MutL homologue 1 (MLH1) and controls the post-transcriptional level of several MMR proteins, including MutS homologue 2 (MSH2). We show that in WT B cells activated for CSR, MBD4 is induced and interacts with MMR proteins, thereby implying a role for MBD4 in CSR. However, CSR is in the normal range in Mbd4 deficient mice deleted for exons 2–5 despite concomitant reduction of MSH2. We show by comparison in Msh2+/− B cells that a two-fold reduction of MSH2 and MBD4 proteins is correlated with impaired CSR. It is therefore surprising that CSR occurs at normal frequencies in the Mbd4 deficient B cells where MSH2 is reduced. We find that a variant Mbd4 transcript spanning exons 1,6–8 is expressed in Mbd4 deficient B cells. This transcript can be ectopically expressed and produces a truncated MBD4 peptide. Thus, the 3′ end of the Mbd4 locus is not silent in Mbd4 deficient B cells and may contribute to CSR. Our findings highlight a complex relationship between MBD4 and MMR proteins in B cells and a potential reconsideration of their role in CSR.
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Affiliation(s)
- Fernando Grigera
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
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Neri P, Bahlis NJ. Genomic instability in multiple myeloma: mechanisms and therapeutic implications. Expert Opin Biol Ther 2013; 13 Suppl 1:S69-82. [PMID: 23782016 DOI: 10.1517/14712598.2013.814637] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Clonal plasma cells in multiple myeloma (MM) are typified by their nearly universal aneuploidy and the presence of recurrent chromosomal aberrations reflecting their chromosomal instability. Multiple myeloma is also recognized to be heterogeneous with distinct molecular subgroups. Deep genome sequencing studies have recently revealed an even wider heterogeneity and genomic instability with the identification of a complex mutational landscape and a branching pattern of clonal evolution. AREAS COVERED Despite the lack of full understanding of the exact mechanisms driving the genomic instability in MM, recent observations have correlated these abnormalities with impairments in the DNA damage repair machinery as well as epigenetic changes. These mechanisms and the resulting therapeutic implications will be the subject of this review. EXPERT OPINION By providing growth advantage of the fittest clone and promoting the acquisition of drug resistance, genomic instability is unarguably beneficial to MM cells, however, it may also well be its Achilles heal by creating exploitable vulnerabilities. As such, targeting presumptive DNA repair defects and other oncogenic addictions represent a promising area of clinical investigation. In particular, by inducing gene or pathway dependencies not present in normal cells, genomic instability can generate targets of contextual synthetic lethality in MM cells.
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Affiliation(s)
- Paola Neri
- University of Calgary, Division of Hematology and Bone Marrow Transplant, Hospital Drive NW, Calgary, AB T2N4N1, Canada
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25
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He Y, Xu X, Chen H, Wang J, Xiong W, Xu Y, Liu J. The hMLH1 promoter polymorphisms and cancer susceptibility in Asian populations: a meta-analysis. Gene 2013; 523:199-204. [PMID: 23587910 DOI: 10.1016/j.gene.2013.03.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 03/20/2013] [Accepted: 03/28/2013] [Indexed: 10/27/2022]
Abstract
BACKGROUND A variety of studies have evaluated the associations between polymorphisms in the promoter regions of the hMLH1 and cancer risk. However, the results remain inconclusive. To better understand the roles of the hMLH1 polymorphisms and cancer risk, we conducted a comprehensive meta-analysis to investigate the association between the hMLH1 -93G/A and 1151T/A (Val384Asp) polymorphisms and cancer risk in Asian population. METHODS We performed a meta-analysis by conducting searches of the published studies in Pub Med, CNKI, CBM, ISI web of knowledge and Google scholar search databases. Finally, 12 studies were included into our meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between hMLH1 polymorphisms and cancer risk. Statistical analysis was performed with Review Manager 5.0. RESULTS Twelve studies addressing two hMLH1 polymorphisms were analyzed among a total of 4128 cancer cases and 4678 controls. For hMLH1 -93G/A, there was no evidence that the hMLH1 -93G/A polymorphism was significantly associated with an increased cancer risk (P>0.05) in Asian populations (heterozygote comparison: OR=0.89 [95% CI (0.75, 1.060)] P=0.20; dominant model comparison: OR=0.98 [95% CI (0.83, 1.15)] P=0.79). In subgroup analysis based on cancer types and the sources of control, no associations were found in colorectal cancer, gastric cancer and "other cancers" under the any gene model except for lung cancer (recessive model comparison: OR=1.69 [95% CI (1.30, 2.19)] P<0.0001). For hMLH1 1151T/A, the polymorphism significantly associated with an increased cancer risk in Asians: OR=1.88 [95% CI (1.49, 2.25)], P<0.0001, and OR=1.87 [95% CI (1.49, 2.25)], P<0.0001. CONCLUSIONS Our investigations demonstrated that the hMLH1 -93G/A polymorphism is not a candidate for susceptibility to overall cancers, and that the hMLH1 1151T/A polymorphism is significantly associated with higher cancer risk in Asian populations. Further studies with large sample size for hMLH1 should be conducted.
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Affiliation(s)
- Yuanzhou He
- Department of Respiratory Diseases, Tongji Hospital, Key Lab of Pulmonary Diseases of Health Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Edelbrock MA, Kaliyaperumal S, Williams KJ. Structural, molecular and cellular functions of MSH2 and MSH6 during DNA mismatch repair, damage signaling and other noncanonical activities. Mutat Res 2013; 743-744:53-66. [PMID: 23391514 DOI: 10.1016/j.mrfmmm.2012.12.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 12/28/2012] [Accepted: 12/31/2012] [Indexed: 11/18/2022]
Abstract
The field of DNA mismatch repair (MMR) has rapidly expanded after the discovery of the MutHLS repair system in bacteria. By the mid 1990s yeast and human homologues to bacterial MutL and MutS had been identified and their contribution to hereditary non-polyposis colorectal cancer (HNPCC; Lynch syndrome) was under intense investigation. The human MutS homologue 6 protein (hMSH6), was first reported in 1995 as a G:T binding partner (GTBP) of hMSH2, forming the hMutSα mismatch-binding complex. Signal transduction from each DNA-bound hMutSα complex is accomplished by the hMutLα heterodimer (hMLH1 and hPMS2). Molecular mechanisms and cellular regulation of individual MMR proteins are now areas of intensive research. This review will focus on molecular mechanisms associated with mismatch binding, as well as emerging evidence that MutSα, and in particular, MSH6, is a key protein in MMR-dependent DNA damage response and communication with other DNA repair pathways within the cell. MSH6 is unstable in the absence of MSH2, however it is the DNA lesion-binding partner of this heterodimer. MSH6, but not MSH2, has a conserved Phe-X-Glu motif that recognizes and binds several different DNA structural distortions, initiating different cellular responses. hMSH6 also contains the nuclear localization sequences required to shuttle hMutSα into the nucleus. For example, upon binding to O(6)meG:T, MSH6 triggers a DNA damage response that involves altered phosphorylation within the N-terminal disordered domain of this unique protein. While many investigations have focused on MMR as a post-replication DNA repair mechanism, MMR proteins are expressed and active in all phases of the cell cycle. There is much more to be discovered about regulatory cellular roles that require the presence of MutSα and, in particular, MSH6.
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Affiliation(s)
| | - Saravanan Kaliyaperumal
- Division of Comparative Medicine and Pathology, New England Primate Research Center, One Pine Hill Drive, Southborough, MA 01772, USA.
| | - Kandace J Williams
- University of Toledo College of Medicine and Life Sciences, Department of Biochemistry & Cancer Biology, 3000 Transverse Dr., Toledo, OH 43614, USA.
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Palles C, Cazier JB, Howarth KM, Domingo E, Jones AM, Broderick P, Kemp Z, Spain SL, Almeida EG, Salguero I, Sherborne A, Chubb D, Carvajal-Carmona LG, Ma Y, Kaur K, Dobbins S, Barclay E, Gorman M, Martin L, Kovac MB, Humphray S, Lucassen A, Holmes C, Bentley D, Donnelly P, Taylor J, Petridis C, Roylance R, Sawyer EJ, Kerr DJ, Clark S, Grimes J, Kearsey SE, Thomas HJW, McVean G, Houlston RS, Tomlinson I. Germline mutations affecting the proofreading domains of POLE and POLD1 predispose to colorectal adenomas and carcinomas. Nat Genet 2013; 45:136-44. [PMID: 23263490 PMCID: PMC3785128 DOI: 10.1038/ng.2503] [Citation(s) in RCA: 725] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/28/2012] [Indexed: 12/11/2022]
Abstract
Many individuals with multiple or large colorectal adenomas or early-onset colorectal cancer (CRC) have no detectable germline mutations in the known cancer predisposition genes. Using whole-genome sequencing, supplemented by linkage and association analysis, we identified specific heterozygous POLE or POLD1 germline variants in several multiple-adenoma and/or CRC cases but in no controls. The variants associated with susceptibility, POLE p.Leu424Val and POLD1 p.Ser478Asn, have high penetrance, and POLD1 mutation was also associated with endometrial cancer predisposition. The mutations map to equivalent sites in the proofreading (exonuclease) domain of DNA polymerases ɛ and δ and are predicted to cause a defect in the correction of mispaired bases inserted during DNA replication. In agreement with this prediction, the tumors from mutation carriers were microsatellite stable but tended to acquire base substitution mutations, as confirmed by yeast functional assays. Further analysis of published data showed that the recently described group of hypermutant, microsatellite-stable CRCs is likely to be caused by somatic POLE mutations affecting the exonuclease domain.
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Affiliation(s)
- Claire Palles
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Jean-Baptiste Cazier
- Bioinformatics and Statistical Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Kimberley M Howarth
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Enric Domingo
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Angela M. Jones
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Peter Broderick
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Zoe Kemp
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sarah L Spain
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Estrella Guarino Almeida
- Dept. of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Israel Salguero
- Dept. of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Amy Sherborne
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Daniel Chubb
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Luis G Carvajal-Carmona
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Yusanne Ma
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Kulvinder Kaur
- Oxford NIHR Comprehensive Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sara Dobbins
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Ella Barclay
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Maggie Gorman
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Lynn Martin
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Michal B Kovac
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Research Group Human Genetics, Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland
| | - Sean Humphray
- Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex CB10 1XL, UK
| | | | | | - Anneke Lucassen
- Wessex Regional Genetics, Princess Anne Hospital, Southampton SO16 5YA UK
| | - Christopher Holmes
- Bioinformatics and Statistical Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Department of Statistics, University of Oxford, South Parks Road, Oxford OX1 3TG, UK
| | - David Bentley
- Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex CB10 1XL, UK
| | - Peter Donnelly
- Bioinformatics and Statistical Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Department of Statistics, University of Oxford, South Parks Road, Oxford OX1 3TG, UK
| | - Jenny Taylor
- Oxford NIHR Comprehensive Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Christos Petridis
- Guy’s, King’s, St Thomas’ Cancer Centre, Guy’s Hospital, London SE1 9RT, UK
| | - Rebecca Roylance
- Institute of Cancer, Bart’s and the London Medical School, Queen Mary College, University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Elinor J Sawyer
- Guy’s, King’s, St Thomas’ Cancer Centre, Guy’s Hospital, London SE1 9RT, UK
| | - David J. Kerr
- Nuffield Department of Clinical Laboratory Sciences, University of Oxford, Oxford OX3 7DU, UK
| | - Susan Clark
- Polyposis Registry, Imperial College School of Medicine, St Mark’s Hospital Watford Road, Harrow, HA1 3UJ, UK
| | - Jonathan Grimes
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Science Division, Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - Stephen E Kearsey
- Dept. of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Huw JW Thomas
- Family Cancer Clinic, Imperial College School of Medicine, St Mark’s Hospital Watford Road, Harrow, HA1 3UJ, UK
| | - Gilean McVean
- Bioinformatics and Statistical Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Richard S Houlston
- Section of Cancer Genetics, Brookes-Lawley Building, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK
| | - Ian Tomlinson
- Molecular and Population Genetics Laboratory, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Oxford NIHR Comprehensive Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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Aberdein D, Munday J, Howe L, French A, Gibson I. Widespread Mismatch Repair Expression in Feline Small Intestinal Lymphomas. J Comp Pathol 2012; 147:24-30. [DOI: 10.1016/j.jcpa.2011.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/05/2011] [Accepted: 08/19/2011] [Indexed: 02/02/2023]
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Dose dependent effects on cell cycle checkpoints and DNA repair by bendamustine. PLoS One 2012; 7:e40342. [PMID: 22768280 PMCID: PMC3386996 DOI: 10.1371/journal.pone.0040342] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/07/2012] [Indexed: 12/02/2022] Open
Abstract
Bendamustine (BDM) is an active chemotherapeutic agent approved in the U. S. for treating chronic lymphocytic leukemia and non-Hodgkin lymphoma. Its chemical structure suggests it may have alkylator and anti-metabolite activities; however the precise mechanism of action is not well understood. Here we report the concentration-dependent effects of BDM on cell cycle, DNA damage, checkpoint response and cell death in HeLa cells. Low concentrations of BDM transiently arrested cells in G2, while a 4-fold higher concentration arrested cells in S phase. DNA damage at 50, but not 200 µM, was efficiently repaired after 48 h treatment, suggesting a difference in DNA repair efficiency at the two concentrations. Indeed, perturbing base-excision repair sensitized cells to lower concentrations of BDM. Timelapse studies of the checkpoint response to BDM showed that inhibiting Chk1 caused both the S- and G2-arrested cells to prematurely enter mitosis. However, whereas the cells arrested in G2 (low dose BDM) entered mitosis, segregated their chromosomes and divided normally, the S-phase arrested cells (high dose BDM) exhibited a highly aberrant mitosis, whereby EM images showed highly fragmented chromosomes. The vast majority of these cells died without ever exiting mitosis. Inhibiting the Chk1-dependent DNA damage checkpoint accelerated the time of killing by BDM. Our studies suggest that BDM may affect different biological processes depending on drug concentration. Sensitizing cells to killing by BDM can be achieved by inhibiting base-excision repair or disrupting the DNA damage checkpoint pathway.
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Hassen S, Ali N, Chowdhury P. Molecular signaling mechanisms of apoptosis in hereditary non-polyposis colorectal cancer. World J Gastrointest Pathophysiol 2012; 3:71-9. [PMID: 22737591 PMCID: PMC3382705 DOI: 10.4291/wjgp.v3.i3.71] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 05/31/2012] [Accepted: 06/12/2012] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as “Lynch syndrome”. It is the most common hereditary form of cancer accounting for 5%-10% of all colon cancers. HNPCC is a dominant autosomal genetic disorder caused by germ line mutations in mismatch repair genes. Human mismatch repair genes play a crucial role in genetic stability of DNA, the inactivation of which results in an increased rate of mutation and often a loss of mismatch repair function. Recent studies have shown that certain mismatch repair genes are involved in the regulation of key cellular processes including apoptosis. Thus, differential expression of mismatch repair genes particularly the contributions of MLH1 and MSH2 play important roles in therapeutic resistance to certain cytotoxic drugs such as cisplatin that is used normally as chemoprevention. An understanding of the role of mismatch repair genes in molecular signaling mechanism of apoptosis and its involvement in HNPCC needs attention for further work into this important area of cancer research, and this review article is intended to accomplish that goal of linkage of apoptosis with HNPCC. The current review was not intended to provide a comprehensive enumeration of the entire body of literature in the area of HNPCC or mismatch repair system or apoptosis; it is rather intended to focus primarily on the current state of knowledge of the role of mismatch repair proteins in molecular signaling mechanism of apoptosis as it relates to understanding of HNPCC.
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31
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Research on plants for the understanding of diseases of nuclear and mitochondrial origin. J Biomed Biotechnol 2012; 2012:836196. [PMID: 22690124 PMCID: PMC3368588 DOI: 10.1155/2012/836196] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/28/2012] [Indexed: 11/17/2022] Open
Abstract
Different model organisms, such as Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mouse, cultured human cell lines, among others, were used to study the mechanisms of several human diseases. Since human genes and proteins have been structurally and functionally conserved in plant organisms, the use of plants, especially Arabidopsis thaliana, as a model system to relate molecular defects to clinical disorders has recently increased. Here, we briefly review our current knowledge of human diseases of nuclear and mitochondrial origin and summarize the experimental findings of plant homologs implicated in each process.
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32
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Xiao XQ, Gong WDA, Wang SZ, Zhang ZD, Rui XP, Wu GZ, Ren F. Polymorphisms of mismatch repair gene hMLH1 and hMSH2 and risk of gastric cancer in a Chinese population. Oncol Lett 2011; 3:591-598. [PMID: 22740958 DOI: 10.3892/ol.2011.517] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 10/04/2011] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study was to determine the genotype and allele frequencies of hMLH1 (-93G>A and I219V) and hMSH2 (-118T>C and IVS12-6T>C) polymorphisms in patients with gastric carcinoma and normal controls, and to evaluate the association between these polymorphisms and the risk of gastric cancer in a hospital-based Chinese population. Genomic DNA was extracted from peripheral blood lymphocytes. A TaqMan assay was used to determine the genotype and allele frequencies of hMLH1 and hMSH2 polymorphisms in data obtained from 554 gastric cancer cases and 592 controls. Unconditional logistic regression was used to assess the association between the four single nucleotide polymorphisms (SNPs) and gastric carcinoma risk. No evidence of an association among any of the four polymorphisms and the risk of gastric cancer was observed. However, when gastric cancer patients were further stratified by age, gender, smoking status, alcohol use and clinicopathological characteristics, and compared with the control populations, the combined variant genotype hMSH2 -118T>C (TC+CC) was not only associated with an increased risk of gastric cancer in subgroups of younger subjects [ages ≤63years; adjusted odds ratio (OR)=1.51, 95% confidence interval (CI), 1.05-2.16], but also with diffuse tumors (adjusted OR=1.41, 95% CI, 1.01-1.96). These data indicate that the polymorphisms of -93G>A, I219V and IVS12-6T>C are not associated with the risk of gastric cancer. However, hMSH2-118T>C combined with variant genotypes (TC+CC) may confer a potential risk of gastric cancer in the Chinese population.
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Affiliation(s)
- Xian-Qiu Xiao
- Department of General Surgery, the 101th Chinese People's Liberation Army Hospital, Jiangsu, P.R. China
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33
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Singh KP, Treas J, Tyagi T, Gao W. DNA demethylation by 5-aza-2-deoxycytidine treatment abrogates 17 beta-estradiol-induced cell growth and restores expression of DNA repair genes in human breast cancer cells. Cancer Lett 2011; 316:62-9. [PMID: 22082530 DOI: 10.1016/j.canlet.2011.10.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/11/2011] [Accepted: 10/15/2011] [Indexed: 12/20/2022]
Abstract
Prolonged exposure to elevated levels of estrogen is a risk factor for breast cancer. Though increased cell growth and loss of DNA repair capacity is one of the proposed mechanisms for estrogen-induced cancers, the mechanism through which estrogen induces cell growth and decreases DNA repair capacity is not clear. DNA hypermethylation is known to inactivate DNA repair genes and apoptotic response in cancer cells. Therefore, the objective of this study was to determine the role of DNA hypermethylation in estrogen-induced cell growth and regulation of DNA repair genes expression in breast cancer cells. To achieve this objective, the estrogen-responsive MCF-7 cells either pretreated with 5-aza-2-deoxycytidine (5-aza-dC) or untreated (as control) were exposed to 17 beta-estradiol (E2), and its effect on cell growth and expression of DNA repair genes were measured. The result revealed that 5-aza-dC abrogates the E2-induced growth in MCF-7 cells. An increased expression of OGG1, MSH4, and MLH1 by 5-aza-dC treatment alone, suggest the DNA hypermethylation as a potential cause for decreased expression of these genes in MCF-7 cells. The decreased expression of ERCC1, XPC, OGG1, and MLH1 by E2 alone and its restoration by co-treatment with 5-aza-dC further suggest that E2 reduces the expression of these DNA repair genes potentially through promoter hypermethylation. Reactivation of mismatch repair (MMR) gene MLH1 and abrogation of E2-induced cell growth by 5-aza-dC treatment suggest that estrogen causes increased growth in breast cancer cells potentially through the inhibition of MMR-mediated apoptotic response. In summary, this study suggests that estrogen increases cell growth and decreases the DNA repair capacity in breast cancer cells, at least in part, through epigenetic mechanism.
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Affiliation(s)
- Kamaleshwar P Singh
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, TX 79409, USA.
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Somatic deletions of genes regulating MSH2 protein stability cause DNA mismatch repair deficiency and drug resistance in human leukemia cells. Nat Med 2011; 17:1298-303. [PMID: 21946537 PMCID: PMC3192247 DOI: 10.1038/nm.2430] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 07/05/2011] [Indexed: 12/14/2022]
Abstract
DNA mismatch repair enzymes (e.g., MSH2) maintain genomic integrity, and their deficiency predisposes to several human cancers and to drug resistance. We found that leukemia cells from a substantial proportion of patients (~11%) with newly diagnosed acute lymphoblastic leukemia (ALL) have low or undetectable MSH2 protein levels (MSH2-L), despite abundant wild-type MSH2 mRNA. MSH2-L leukemia cells contained partial or complete somatic deletions of 1–4 genes that regulate MSH2 degradation (FRAP1, HERC1, PRKCZ, PIK3C2B); these deletions were also found in adult ALL (16%) and sporadic colorectal cancer (13.5%). Knockdown of these genes in human leukemia cells recapitulated the MSH2 protein deficiency by enhancing MSH2-degradation, leading to significant reduction in DNA mismatch repair (MMR) and increased resistance to thiopurines. These findings reveal a previously unrecognized mechanism whereby somatic deletions of genes regulating MSH2 degradation result in undetectable levels of MSH2 protein in leukemia cells, MMR deficiency and drug resistance.
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Pan XM, Yang WZ, Xu GH, Bai P, Qin HJ, Zhang LS, Zhai XD, Tang M, Deng W, Zhang L, Gao LB. The association between MLH1 -93 G>A polymorphism of DNA mismatch repair and cancer susceptibility: a meta-analysis. Mutagenesis 2011; 26:667-73. [PMID: 21745804 DOI: 10.1093/mutage/ger032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
DNA mismatch repair, known as a fundamentally biological pathway, plays key roles in maintaining genomic stability, eliminating mismatch bases and preventing both mutagenesis in the short term and cancerogenesis in the long term. Polymorphisms of MLH1 in individuals may have an effect on the DNA repair capacity and therefore on cancer risk. Recently, emerging studies have been done to evaluate the association between MLH1 -93 G/A polymorphism and cancer risk in diverse populations. However, the results remain conflicting rather than conclusive. In this meta-analysis, we assessed reported studies of association between the MLH1 -93 G/A polymorphism and cancer risk including 13 691 cancer cases and 14 068 controls from 17 published studies. A borderline significant association between the MLH1 -93 G/A polymorphism and cancer risk was observed in overall analysis [heterozygote: odds ratio (OR) = 1.15; 95% confidence interval (CI) 1.05-1.26; homozygote: OR = 1.21; 95% CI, 1.04-1.40; dominant model: OR = 1.13; 95% CI 1.01-1.26; recessive model: OR = 1.21; 95% CI 1.07-1.35, respectively]. In subgroup analysis by ethnicity, significantly increased risks were found in Asian population and mixed population but not in Caucasian population. After stratified analysis according to the quality of literature, increased cancer risks were observed in the studies of lower quality but not in the studies of higher quality. Similarly, elevated cancer risks were observed in hospital-based studies but not in population-based studies. These findings showed no persuasive evidence that MLH1 -93 G/A polymorphism was associated with an increased risk of cancer. On the conservative standpoint, well-designed population-based studies with larger sample size in different ethnic groups should be performed to further confirm these results.
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Affiliation(s)
- Xin-Min Pan
- Department of Forensic Pathology, College of Forensic Medicine, Henan University of Science and Technology, 31 Anhui Road, Jianxi District, Luoyang, Henan 471003, People's Republic of China
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36
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Kovtun IV, Harris KJ, Jatoi A, Jevremovic D. Increased incidence of endometrioid tumors caused by aberrations in E-cadherin promoter of mismatch repair-deficient mice. Carcinogenesis 2011; 32:1085-92. [PMID: 21551128 PMCID: PMC3128562 DOI: 10.1093/carcin/bgr080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 04/15/2011] [Accepted: 04/19/2011] [Indexed: 01/05/2023] Open
Abstract
Loss of E-cadherin expression is a critical step in the development and progression of gynecological tumors. Study of the precise role of E-cadherin has been hampered by the lack of satisfactory mouse model for E-cadherin deficiency. Likewise, DNA mismatch repair (MMR) is implicated in gynecological tumorigenesis, but knockout of MMR in mice predominantly causes hematologic neoplasms. Here, we show that combined disruption of E-cadherin and DNA MMR pathways increases incidence of endometrioid tumors in mice. Twenty percent of mice knockout for Msh2 enzyme and hemizygous for E-cadherin [Msh2(-/-)/Cdh1(+/-)] developed endometrioid-like tumors in the ovary, uterus and genital area. Characteristic of these tumors was a complete loss of E-cadherin expression. Sequence analysis of E-cadherin promoter region demonstrated that the loss of E-cadherin expression is caused by inactivating mutations, implying that E-cadherin is a mutational target in Msh2-deficient mice. In addition, Msh2(-/-)/Cdh1(+/-) mice showed a reduction in overall survival as compared with their Msh2(-/-) counterparts due to the development of more aggressive lymphomas, suggesting a specific role of E-cadherin in lymphomagenesis. In conclusion, Msh2(-/-)/Cdh1(+/-) mice provide a good model of gynecological tumorigenesis and may be useful for testing molecular target-specific therapies.
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Affiliation(s)
- Irina V Kovtun
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA.
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Souza LR, Fonseca-Silva T, Pereira CS, Santos EP, Lima LC, Carvalho HA, Gomez RS, Guimarães ALS, De Paula AMB. Immunohistochemical analysis of p53, APE1, hMSH2 and ERCC1 proteins in actinic cheilitis and lip squamous cell carcinoma. Histopathology 2011; 58:352-60. [PMID: 21323960 DOI: 10.1111/j.1365-2559.2011.03756.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AIMS This study has compared the tissue expression of the p53 tumour suppressor protein and DNA repair proteins APE1, hMSH2 and ERCC1 in normal, dysplastic and malignant lip epithelium. METHODS AND RESULTS Morphological analysis and immunohistochemistry were performed on archived specimens of normal lip mucosa (n=15), actinic cheilitis (AC) (n=30), and lip squamous cell carcinoma (LSCC) (n=27). AC samples were classified morphologically according to the severity of epithelial dysplasia and risk of malignant transformation. LSCC samples were morphologically staged according to WHO and invasive front grading (IFG) criteria. Differences between groups and morphological stages were determined by bivariate statistical analysis. Progressive increases in the percentage of epithelial cells expressing p53 and APE1 were associated with increases in morphological malignancy from normal lip mucosa to LSCC. There was also a significant reduction in epithelial cells expressing hMSH2 and ERCC1 proteins in the AC and LSCC groups. A higher percentage of malignant cells expressing APE1 was found in samples with an aggressive morphological IFG grade. CONCLUSIONS Our data showed that epithelial cells from premalignant to malignant lip disease exhibited changes in the expression of p53, APE1, hMSH2 and ERCC1 proteins; these molecular change might contribute to lip carcinogenesis.
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Affiliation(s)
- Ludmilla R Souza
- Health Science Programme, State University of Montes Claros, Montes Claros, MG, Brazil
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Luncsford PJ, Chang DY, Shi G, Bernstein J, Madabushi A, Patterson DN, Lu AL, Toth EA. A structural hinge in eukaryotic MutY homologues mediates catalytic activity and Rad9-Rad1-Hus1 checkpoint complex interactions. J Mol Biol 2010; 403:351-70. [PMID: 20816984 DOI: 10.1016/j.jmb.2010.08.045] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/25/2010] [Accepted: 08/25/2010] [Indexed: 02/07/2023]
Abstract
The DNA glycosylase MutY homologue (MYH or MUTYH) removes adenines misincorporated opposite 8-oxoguanine as part of the base excision repair pathway. Importantly, defects in human MYH (hMYH) activity cause the inherited colorectal cancer syndrome MYH-associated polyposis. A key feature of MYH activity is its coordination with cell cycle checkpoint via interaction with the Rad9-Rad1-Hus1 (9-1-1) complex. The 9-1-1 complex facilitates cell cycle checkpoint activity and coordinates this activity with ongoing DNA repair. The interdomain connector (IDC, residues 295-350) between the catalytic domain and the 8-oxoguanine recognition domain of hMYH is a critical element that maintains interactions with the 9-1-1 complex. We report the first crystal structure of a eukaryotic MutY protein, a fragment of hMYH (residues 65-350) that consists of the catalytic domain and the IDC. Our structure reveals that the IDC adopts a stabilized conformation projecting away from the catalytic domain to form a docking scaffold for 9-1-1. We further examined the role of the IDC using Schizosaccharomyces pombe MYH as model system. In vitro studies of S. pombe MYH identified residues I261 and E262 of the IDC (equivalent to V315 and E316 of the hMYH IDC) as critical for maintaining the MYH/9-1-1 interaction. We determined that the eukaryotic IDC is also required for DNA damage selection and robust enzymatic activity. Our studies also provide the first evidence that disruption of the MYH/9-1-1 interaction diminishes the repair of oxidative DNA damage in vivo. Thus, preserving the MYH/9-1-1 interaction contributes significantly to minimizing the mutagenic potential of oxidative DNA damage.
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Affiliation(s)
- Paz J Luncsford
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
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Vasilyeva A, Clodfelter JE, Gorczynski MJ, Gerardi AR, King SB, Salsbury F, Scarpinato KD. Parameters of Reserpine Analogs That Induce MSH2/MSH6-Dependent Cytotoxic Response. J Nucleic Acids 2010; 2010. [PMID: 20936178 PMCID: PMC2946608 DOI: 10.4061/2010/162018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/02/2010] [Accepted: 06/18/2010] [Indexed: 11/20/2022] Open
Abstract
Mismatch repair proteins modulate the cytotoxicity of several chemotherapeutic agents. We have recently proposed a "death conformation" of the MutS homologous proteins that is distinguishable from their "repair conformation." This conformation can be induced by a small molecule, reserpine, leading to DNA-independent cell death. We investigated the parameters for a small reserpine-like molecule that are required to interact with MSH2/MSH6 to induce MSH2/MSH6-dependent cytotoxic response. A multidisciplinary approach involving structural modeling, chemical synthesis, and cell biology analyzed reserpine analogs and modifications. We demonstrate that the parameters controlling the induction of MSH2/MSH6-dependent cytotoxicity for reserpine-analogous molecules reside in the specific requirements for methoxy groups, the size of the molecule, and the orientation of molecules within the protein-binding pocket. Reserpine analog rescinnamine showed improved MSH2-dependent cytotoxicity. These results have important implications for the identification of compounds that require functional MMR proteins to exhibit their full cytotoxicity, which will avoid resistance in MMR-deficient cells.
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Affiliation(s)
- Aksana Vasilyeva
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Brieger A, Adryan B, Wolpert F, Passmann S, Zeuzem S, Trojan J. Cytoskeletal scaffolding proteins interact with Lynch-Syndrome associated mismatch repair protein MLH1. Proteomics 2010; 10:3343-55. [DOI: 10.1002/pmic.200900672] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Srivastava K, Srivastava A, Mittal B. Polymorphisms in ERCC2, MSH2, and OGG1 DNA repair genes and gallbladder cancer risk in a population of Northern India. Cancer 2010; 116:3160-9. [PMID: 20564624 DOI: 10.1002/cncr.25063] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Genetic variants of DNA repair enzymes may lead to genetic instability and contribute to gallbladder (GB) carcinogenesis. METHODS A case-control study (230 GB carcinogenesis patients and 230 controls) was undertaken to evaluate whether genetic variations in 3 DNA repair genes ERCC2 (Asp312Asn [rs1799793] and Lys751Gln [rs13181]), MSH2 (-118T > C [rs2303425] and IVS1 + 9G>C [rs2303426]), and OGG1 (Ser326Cys [rs1052133] and 748-15C > G [rs2072668]) are associated with GB carcinogenesis risk in a North Indian population. RESULTS The authors found that the ERCC2 Asp312Asn AA, MSH2 IVS1 + 9G > C CC, OGG1 Ser326Cys GG and CG + GG, and OGG1 748-15C > G GG and CG + GG genotypes were significantly associated with an increased risk of GB carcinogenesis (odds ratio [OR], 2.1, 1.8, 2.5, 1.8, 2.0, and 1.6, respectively). In contrast, ERCC2 Lys751Gln, and MSH2 -118T > C markers showed no significant associations with GB carcinogenesis risk, although because of the small sample size their effects cannot be ruled out. Female GB carcinogenesis patients with the OGG1 748-15C > G GG, OGG1 Ser326Cys GG, and ERCC2 Asp312Asn genotypes had a greater risk for developing the disease (OR, 3.6, 7.7, and 2.7, respectively). There was a significant interaction between MSH2 IVS1 + 9G > C and OGG1 748-15C > G polymorphisms (P = .001). Furthermore, individuals with > 6 variant alleles of the studied polymorphisms were at 4-fold increased risk for developing GB carcinogenesis. Classification and Regression Tree analysis revealed potential higher-order gene-gene interactions and categorized a few higher-risk subgroups for GB carcinogenesis. CONCLUSIONS These results suggest that genetic variants in the DNA repair pathways may be involved in GB carcinogenesis etiology.
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Affiliation(s)
- Kshitij Srivastava
- Department of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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Cantor SB, Xie J. Assessing the link between BACH1/FANCJ and MLH1 in DNA crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:500-507. [PMID: 20658644 DOI: 10.1002/em.20568] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
FANCJ (also known as BRIP1 or BACH1) is a DNA helicase that was originally identified by its direct interaction with the hereditary breast cancer protein, BRCA1. Similar to BRCA1, FANCJ function is essential for DNA repair and breast cancer suppression. FANCJ is also mutated in the cancer prone syndrome Fanconi anemia, for which patient cells are characterized by extreme sensitivity to agents that generate DNA interstand crosslinks. Unexpectedly, correction of the interstrand crosslink sensitivity of FANCJ-null patient cells did not require the FANCJ/BRCA1 interaction. Instead, FANCJ binding to the mismatch repair protein, MLH1 was required. Given this finding, we address the role of FANCJ and MLH1 in DNA crosslink processing and how their functions could be linked in checkpoint and/or recombination pathways. We speculate that after DNA crosslink processing and repair, the FANCJ/MLH1 interaction is critical for recovery and restart of replication. These ideas are considered and summarized in this review.
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Affiliation(s)
- Sharon B Cantor
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Perrett CM, Harwood CA, McGregor JM, Warwick J, Cerio R, Karran P. Expression of DNA mismatch repair proteins and MSH2 polymorphisms in nonmelanoma skin cancers of organ transplant recipients. Br J Dermatol 2010; 162:732-42. [PMID: 19818066 DOI: 10.1111/j.1365-2133.2009.09550.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Organ transplant recipients (OTRs) have an increased risk of skin cancer. Treatment with azathioprine, commonly used in post-transplant immunosuppressive regimens, results in incorporation of 6-thioguanine (6-TG) into DNA. Mismatch repair (MMR)-defective cells are resistant to killing by 6-TG. Azathioprine exposure confers a survival advantage on MMR-defective cells, which are hypermutable and may therefore contribute to azathioprine-related nonmelanoma skin cancer, a phenomenon we have previously demonstrated in transplant-associated sebaceous carcinomas. The MSH2 protein is an important component of DNA MMR. The -6 exon 13 T>C MSH2 polymorphism is associated with impaired MMR, drug resistance and certain cancers. OBJECTIVES To investigate (i) whether loss of MMR protein expression and microsatellite instability are over-represented in squamous cell carcinomas (SCCs) from OTRs on azathioprine compared with SCCs from immunocompetent patients, and (ii) whether the MSH2 -6 exon 13 polymorphism is over-represented in OTRs with skin cancer on azathioprine. METHODS (i) Immunohistochemical staining was used to assess expression of the MMR proteins MSH2 and MLH1 in cutaneous SCCs from OTRs on azathioprine and from immunocompetent patients. (ii) Blood samples from OTRs on azathioprine with and without skin cancer were genotyped for the -6 exon 13 MSH2 polymorphism. RESULTS (i) MSH2 and MLH1 protein expression was not altered in SCCs from OTRs on azathioprine and there was no difference in expression between SCCs from OTRs and immunocompetent patients. (ii) There was no association between MSH2 polymorphism genotype frequency and OTR skin cancer status. CONCLUSIONS Despite previous findings in transplant-associated sebaceous carcinomas, defective MMR and the -6 exon 13 MSH2 polymorphism are unlikely to play a significant role in the development of SCC in OTRs on azathioprine.
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Affiliation(s)
- C M Perrett
- Centre for Cutaneous Research and Department of Dermatology, Institute of Cell and Molecular Science, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, 4 Newark Street, London E1 2AT, U.K.
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Bertoni C, Rustagi A, Rando TA. Enhanced gene repair mediated by methyl-CpG-modified single-stranded oligonucleotides. Nucleic Acids Res 2010; 37:7468-82. [PMID: 19854937 PMCID: PMC2794159 DOI: 10.1093/nar/gkp757] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gene editing mediated by oligonucleotides has been shown to induce stable single base alterations in genomic DNA in both prokaryotic and eukaryotic organisms. However, the low frequencies of gene repair have limited its applicability for both basic manipulation of genomic sequences and for the development of therapeutic approaches for genetic disorders. Here, we show that single-stranded oligodeoxynucleotides (ssODNs) containing a methyl-CpG modification and capable of binding to the methyl-CpG binding domain protein 4 (MBD4) are able to induce >10-fold higher levels of gene correction than ssODNs lacking the specific modification. Correction was stably inherited through cell division and was confirmed at the protein, transcript and genomic levels. Downregulation of MBD4 expression using RNAi prevented the enhancement of gene correction efficacy obtained using the methyl-CpG-modified ssODN, demonstrating the specificity of the repair mechanism being recruited. Our data demonstrate that efficient manipulation of genomic targets can be achieved and controlled by the type of ssODN used and by modulation of the repair mechanism involved in the correction process. This new generation of ssODNs represents an important technological advance that is likely to have an impact on multiple applications, especially for gene therapy where permanent correction of the genetic defect has clear advantages over viral and other nonviral approaches currently being tested.
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Affiliation(s)
- Carmen Bertoni
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Bilbao C, Lara PC, Ramírez R, Henríquez-Hernández LA, Rodríguez G, Falcón O, León L, Perucho M, Díaz-Chico BN, Díaz-Chico JC. Microsatellite instability predicts clinical outcome in radiation-treated endometrioid endometrial cancer. Int J Radiat Oncol Biol Phys 2010; 76:9-13. [PMID: 20005452 DOI: 10.1016/j.ijrobp.2009.09.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 09/18/2009] [Accepted: 09/18/2009] [Indexed: 12/21/2022]
Abstract
PURPOSE To elucidate whether microsatellite instability (MSI) predicts clinical outcome in radiation-treated endometrioid endometrial cancer (EEC). METHODS AND MATERIALS A consecutive series of 93 patients with EEC treated with extrafascial hysterectomy and postoperative radiotherapy was studied. The median clinical follow-up of patients was 138 months, with a maximum of 232 months. Five quasimonomorphic mononucleotide markers (BAT-25, BAT-26, NR21, NR24, and NR27) were used for MSI classification. RESULTS Twenty-five patients (22%) were classified as MSI. Both in the whole series and in early stages (I and II), univariate analysis showed a significant association between MSI and poorer 10-year local disease-free survival, disease-free survival, and cancer-specific survival. In multivariate analysis, MSI was excluded from the final regression model in the whole series, but in early stages MSI provided additional significant predictive information independent of traditional prognostic and predictive factors (age, stage, grade, and vascular invasion) for disease-free survival (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.01-10.49; p = 0.048) and cancer-specific survival (HR 4.20, 95% CI 1.23-14.35; p = 0.022) and was marginally significant for local disease-free survival (HR 3.54, 95% CI 0.93-13.46; p = 0.064). CONCLUSIONS These results suggest that MSI may predict radiotherapy response in early-stage EEC.
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Affiliation(s)
- Cristina Bilbao
- Canary Institute for Cancer Research, Las Palmas de Gran Canaria, Canary Islands, Spain.
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DNA mismatch repair and the transition to hormone independence in breast and prostate cancer. Cancer Lett 2009; 291:142-9. [PMID: 19896265 DOI: 10.1016/j.canlet.2009.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 09/23/2009] [Accepted: 10/09/2009] [Indexed: 02/07/2023]
Abstract
The molecular basis for the progression of breast and prostate cancer from hormone dependent to hormone independent disease remains a critical issue in the management of these two cancers. The DNA mismatch repair system is integral to the maintenance of genomic stability and suppression of tumorigenesis. No firm consensus exists regarding the implications of mismatch repair (MMR) deficiencies in the development of breast or prostate cancer. However, recent studies have reported an association between mismatch repair deficiency and loss of specific hormone receptors, inferring a potential role for mismatch repair deficiency in this transition. An updated review of the experimental data supporting or contradicting the involvement of MMR defects in the development and progression of breast and prostate cancer will be provided with particular emphasis on their implications in the transition to hormone independence.
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Abstract
Microsatellite instability (MSI) is the hallmark of a molecular pathway to carcinogenesis due to sporadic or inherited abnormalities of DNA mismatch repair genes. Inherited mutations are seen in hereditary nonpolyposis colorectal cancer syndrome. Endometrial carcinoma shows as high an incidence of MSI as does colorectal carcinoma. This review provides a framework for the gynecologic pathologist to understand the complexities of MSI in endometrial carcinoma, by discussing the basic mechanisms of mismatch repair and carcinogenesis, testing, the morphologic features of MSI endometrial cancer and the contradictory data regarding prognosis.
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Ruzov A, Shorning B, Mortusewicz O, Dunican DS, Leonhardt H, Meehan RR. MBD4 and MLH1 are required for apoptotic induction in xDNMT1-depleted embryos. Development 2009; 136:2277-86. [PMID: 19502488 DOI: 10.1242/dev.032227] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Loss of the of the maintenance methyltransferase xDNMT1 during Xenopus development results in premature transcription and activation of a p53-dependent apoptotic program that accounts for embryo lethality. Here, we show that activation of the apoptotic response is signalled through the methyl-CpG binding protein xMBD4 and the mismatch repair pathway protein xMLH1. Depletion of xMBD4 or xMLH1 increases the survival rate of xDNMT1-depleted embryos, whereas overexpression of these proteins in embryos induces programmed cell death at the onset of gastrulation. MBD4 interacts directly with both DNMT1 and MLH1, leading to recruitment of the latter to heterochromatic sites that are coincident with DNMT1 localisation. Time-lapse microscopy of micro-irradiated mammalian cells shows that MLH1/MBD4 (like DNMT1) can accumulate at DNA damage sites. We propose that xMBD4/xMLH1 participates in a novel G2 checkpoint that is responsive to xDNMT1p levels in developing embryos and cells.
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Affiliation(s)
- Alexey Ruzov
- Human Genetics Unit, MRC, IGMM, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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Ding X, Mohd AB, Huang Z, Baba T, Bernardini MQ, Lyerly HK, Berchuck A, Murphy SK, Buermeyer AB, Devi GR. MLH1 expression sensitises ovarian cancer cells to cell death mediated by XIAP inhibition. Br J Cancer 2009; 101:269-77. [PMID: 19603033 PMCID: PMC2720211 DOI: 10.1038/sj.bjc.6605180] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND The X-linked inhibitor of apoptosis protein (XIAP), an endogenous apoptosis suppressor, can determine the level of caspase accumulation and the resultant response to apoptosis-inducing agents such as cisplatin in epithelial ovarian cancer (EOC). In addition, the mismatch repair protein, hMLH1, has been linked to DNA damage-induced apoptosis by cisplatin by both p53-dependent and -independent mechanisms. METHODS In this study, hMLH1 expression was correlated with clinical response to platinum drugs and survival in advanced stage (III-IV) EOC patients. We then investigated whether MLH1 loss was a determinant in anti-apoptosis response to cisplatin mediated by XIAP in isogenic and established EOC cell lines with differential p53 status. RESULTS The percentage of cells undergoing cisplatin-induced cell killing was higher in MLH1-proficient cells than in MLH1-defective cells. In addition, the presence of wild-type hMLH1 or hMLH1 re-expression significantly increased sensitivity to 6-thioguanine, a MMR-dependent agent. Cell-death response to 6-thioguanine and cisplatin was associated with significant proteolysis of MLH1, with XIAP destabilisation and increased caspase-3 activity. The siRNA-mediated inhibition of XIAP increased MLH1 proteolysis and cell death in MLH1-proficient cells but not in MLH1-defective cells. CONCLUSION These data suggest that XIAP inhibitors may prove to be an effective means of sensitising EOC to MLH1-dependent apoptosis.
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Affiliation(s)
- X Ding
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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Spampinato CP, Gomez RL, Galles C, Lario LD. From bacteria to plants: a compendium of mismatch repair assays. Mutat Res 2009; 682:110-28. [PMID: 19622396 DOI: 10.1016/j.mrrev.2009.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 06/16/2009] [Accepted: 07/13/2009] [Indexed: 10/20/2022]
Abstract
Mismatch repair (MMR) system maintains genome integrity by correcting mispaired or unpaired bases which have escaped the proofreading activity of DNA polymerases. The basic features of the pathway have been highly conserved throughout evolution, although the nature and number of the proteins involved in the mechanism vary from prokaryotes to eukaryotes and even between humans and plants. Cells deficient in MMR genes have been observed to display a mutator phenotype characterized by an increased rate in spontaneous mutation, instability of microsatellite sequences and illegitimate recombination between diverged DNA sequences. Studies of the mutator phenotype have demonstrated a critical role for the MMR system in mutation avoidance and genetic stability. Here, we briefly review our current knowledge of the MMR mechanism and then focus on the in vivo biochemical and genetic assays used to investigate the function of the MMR proteins in processing DNA mismatches generated during replication and mitotic recombination in Escherichia coli, Saccharomyces cerevisiae, Homo sapiens and Arabidopsis thaliana. An overview of the biochemical assays developed to study mismatch correction in vitro is also provided.
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Affiliation(s)
- Claudia P Spampinato
- Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina.
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