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Lorca V, Garre P. Current status of the genetic susceptibility in attenuated adenomatous polyposis. World J Gastrointest Oncol 2019; 11:1101-1114. [PMID: 31908716 PMCID: PMC6937445 DOI: 10.4251/wjgo.v11.i12.1101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/18/2019] [Accepted: 10/14/2019] [Indexed: 02/05/2023] Open
Abstract
Adenomatous polyposis (AP) is classified according to cumulative adenoma number in classical AP (CAP) and attenuated AP (AAP). Genetic susceptibility is the major risk factor in CAP due to mutations in the known high predisposition genes APC and MUTYH. However, the contribution of genetic susceptibility to AAP is lower and less understood. New predisposition genes have been recently proposed, and some of them have been validated, but their scarcity hinders accurate risk estimations and prevalence calculations. AAP is a heterogeneous condition in terms of severity, clinical features and heritability. Therefore, clinicians do not have strong discriminating criteria for the recommendation of the genetic study of known predisposition genes, and the detection rate is low. Elucidation and knowledge of new AAP high predisposition genes are of great importance to offer accurate genetic counseling to the patient and family members. This review aims to update the genetic knowledge of AAP, and to expound the difficulties involved in the genetic analysis of a highly heterogeneous condition such as AAP.
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Affiliation(s)
- Víctor Lorca
- Laboratorio de Oncología Molecular, Grupo de Investigación Clínica y Traslacional en Oncología, Hospital Clínico San Carlos, Madrid 28040, Spain
| | - Pilar Garre
- Laboratorio de Oncología Molecular, Servicio de Oncología, Hospital Clínico San Carlos, Madrid 28040, Spain
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Defects in the GINS complex increase the instability of repetitive sequences via a recombination-dependent mechanism. PLoS Genet 2019; 15:e1008494. [PMID: 31815930 PMCID: PMC6922473 DOI: 10.1371/journal.pgen.1008494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/19/2019] [Accepted: 10/25/2019] [Indexed: 12/16/2022] Open
Abstract
Faithful replication and repair of DNA lesions ensure genome maintenance. During replication in eukaryotic cells, DNA is unwound by the CMG helicase complex, which is composed of three major components: the Cdc45 protein, Mcm2-7, and the GINS complex. The CMG in complex with DNA polymerase epsilon (CMG-E) participates in the establishment and progression of the replisome. Impaired functioning of the CMG-E was shown to induce genomic instability and promote the development of various diseases. Therefore, CMG-E components play important roles as caretakers of the genome. In Saccharomyces cerevisiae, the GINS complex is composed of the Psf1, Psf2, Psf3, and Sld5 essential subunits. The Psf1-1 mutant form fails to interact with Psf3, resulting in impaired replisome assembly and chromosome replication. Here, we show increased instability of repeat tracts (mononucleotide, dinucleotide, trinucleotide and longer) in yeast psf1-1 mutants. To identify the mechanisms underlying this effect, we analyzed repeated sequence instability using derivatives of psf1-1 strains lacking genes involved in translesion synthesis, recombination, or mismatch repair. Among these derivatives, deletion of RAD52, RAD51, MMS2, POL32, or PIF1 significantly decreased DNA repeat instability. These results, together with the observed increased amounts of single-stranded DNA regions and Rfa1 foci suggest that recombinational mechanisms make important contributions to repeat tract instability in psf1-1 cells. We propose that defective functioning of the CMG-E complex in psf1-1 cells impairs the progression of DNA replication what increases the contribution of repair mechanisms such as template switch and break-induced replication. These processes require sequence homology search which in case of a repeated DNA tract may result in misalignment leading to its expansion or contraction. Processes that ensure genome stability are crucial for all organisms to avoid mutations and decrease the risk of diseases. The coordinated activity of mechanisms underlying the maintenance of high-fidelity DNA duplication and repair is critical to deal with the malfunction of replication forks or DNA damage. Repeated sequences in DNA are particularly prone to instability; these sequences undergo expansions or contractions, leading in humans to various neurological, neurodegenerative, and neuromuscular disorders. A mutant form of one of the noncatalytic subunits of active DNA helicase complex impairs DNA replication. Here, we show that this form also significantly increases the instability of mononucleotide, dinucleotide, trinucleotide and longer repeat tracts. Our results suggest that in cells that harbor a mutated variant of the helicase complex, continuation of DNA replication is facilitated by recombination processes, and this mechanism can be highly mutagenic during repair synthesis through repetitive regions, especially regions that form secondary structures. Our results indicate that proper functioning of the DNA helicase complex is crucial for maintenance of the stability of repeated DNA sequences, especially in the context of recently described disorders in which mutations or deregulation of the human homologs of genes encoding DNA helicase subunits were observed.
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Bakhtiari E, Monfared AS, Niaki HA, Borzoueisileh S, Niksirat F, Fattahi S, Monfared MK, Gorji KE. The expression of MLH1 and MSH2 genes among inhabitants of high background radiation area of Ramsar, Iran. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 208-209:106012. [PMID: 31323602 DOI: 10.1016/j.jenvrad.2019.106012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 06/16/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
Previous studies evidenced the critical role of the mismatch repair system in DNA damage recognition, cell cycle arrest, apoptosis and DNA repair. MLH1 and MSH2 genes belong to repairing complexes of mismatch repair system. The side effects of ionizing radiation on the human health were proved, but researches on the inhabitants of high background radiation areas, with extra-ordinary radiation exposure, showed that the prevalence of cancer or radiation-related diseases is not significantly higher than normal background areas. The city of Ramsar, in northern Iran, has the highest level of natural background radiation in the world and in this study, we aimed to evaluate the expression of MLH1 and MSH2 genes among the inhabitants of high background radiation areas of Ramsar compared to normal background radiation areas. In the present study, 60 blood sample from high and normal background inhabitants were collected and we MLH1, and MSH2 genes expressions in residents of high background radiation area compared with normal background radiation area were evaluated by Quantitative Real-Time PCR. Our results showed a significant upregulation of MLH1 in residents of high background radiation area. Also, there is a significant association between MLH1 and MSH2 gene expression in both sexes. Also, the increased expression of MLH1 in HBRA is notable. There is an increased expression of MLH1 in age above 50 and a decreased expression of MSH2 in ages under 50 years (P < 0.0001). These findings are suggesting the triggering of Mismatch Repair system in response to high-level of natural background radiation.
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Affiliation(s)
- Elahe Bakhtiari
- Student Research Committee, Babol University of Medical Sciences, Babol, I.R Iran; Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R.Iran
| | - Ali Shabestani Monfared
- Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R.Iran
| | - Hale Akhavan Niaki
- Department of Genetics, School of Medicine, Babol University of Medical Sciences, Babol, I.R Iran
| | - Sajad Borzoueisileh
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R.Iran
| | - Fatemeh Niksirat
- Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, I.R Iran
| | - Sadegh Fattahi
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R.Iran; North Research Centre of Pasteur Institute, Amol, I.R.Iran
| | - Mohadese Kosari Monfared
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R.Iran
| | - Kourosh Ebrahimnejad Gorji
- Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, I.R Iran.
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Goellner EM. Chromatin remodeling and mismatch repair: Access and excision. DNA Repair (Amst) 2019; 85:102733. [PMID: 31698199 DOI: 10.1016/j.dnarep.2019.102733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/06/2019] [Accepted: 10/09/2019] [Indexed: 01/03/2023]
Abstract
DNA mismatch repair (MMR) increases replication fidelity and genome stability by correcting DNA polymerase errors that remain after replication. Defects in MMR result in the accumulation of mutations and lead to human tumor development. Germline mutations in MMR cause the hereditary cancer syndrome, Lynch syndrome. After replication, DNA is reorganized into its chromatin structure and wrapped around histone octamers. DNA MMR is thought to be less efficient in recognizing and repairing mispairs packaged in chromatin, in which case MMR must either compete for access to naked DNA before histone deposition or actively move nucleosomes to access the mispair. This article reviews studies into the mechanistic and physical interactions between MMR and various chromatin-associated factors, including the histone deposition complex CAF1. Recent Xenopus and Saccharomyces cerevisiae studies describe a physical interaction between Msh2 and chromatin-remodeling ATPase Fun30/SMARCAD1, with potential mechanistic roles for SMARCAD1 in moving histones for both mispair access and excision tract elongation. The RSC complex, another histone remodeling complex, also potentially influences excision tract length. Deletion mutations of RSC2 point to mechanistic interactions with the MMR pathways. Together, these studies paint a picture of complex interactions between MMR and the chromatin environment that will require numerous additional genetic, biochemical, and cell biology experiments to fully understand. Understanding how these pathways interconnect is essential in fully understanding eukaryotic MMR and has numerous implications in human tumor formation and treatment.
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Affiliation(s)
- Eva M Goellner
- Department of Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, 40536, USA.
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Novel Genetic Markers for Early Detection of Elevated Breast Cancer Risk in Women. Int J Mol Sci 2019; 20:ijms20194828. [PMID: 31569399 PMCID: PMC6801521 DOI: 10.3390/ijms20194828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/20/2019] [Accepted: 09/25/2019] [Indexed: 12/25/2022] Open
Abstract
This study suggests that two newly discovered variants in the MSH2 gene, which codes for a DNA mismatch repair (MMR) protein, can be associated with a high risk of breast cancer. While variants in the MSH2 gene are known to be linked with an elevated cancer risk, the MSH2 gene is not a part of the standard kit for testing patients for elevated breast cancer risk. Here we used the results of genetic testing of women diagnosed with breast cancer, but who did not have variants in BRCA1 and BRCA2 genes. Instead, the test identified four variants with unknown significance (VUS) in the MSH2 gene. Here, we carried in silico analysis to develop a classifier that can distinguish pathogenic from benign mutations in MSH2 genes taken from ClinVar. The classifier was then used to classify VUS in MSH2 genes, and two of them, p.Ala272Val and p.Met592Val, were predicted to be pathogenic mutations. These two mutations were found in women with breast cancer who did not have mutations in BRCA1 and BRCA2 genes, and thus they are suggested to be considered as new bio-markers for the early detection of elevated breast cancer risk. However, before this is done, an in vitro validation of mutation pathogenicity is needed and, moreover, the presence of these mutations should be demonstrated in a higher number of patients or in families with breast cancer history.
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Hashmi AA, Mudassir G, Hashmi RN, Irfan M, Asif H, Khan EY, Abu Bakar SM, Faridi N. Microsatellite Instability in Endometrial Carcinoma by Immunohistochemistry, Association with Clinical and Histopathologic Parameters. Asian Pac J Cancer Prev 2019; 20:2601-2606. [PMID: 31554352 PMCID: PMC6976824 DOI: 10.31557/apjcp.2019.20.9.2601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Indexed: 11/25/2022] Open
Abstract
Objective: We aimed to investigate the frequency of microsatellite instability (MSI) in endometrial carcinoma in our
population and its association with clinico-pathologic features. Methods: A total of 126 cases of primary endometrial
carcinoma were included in the study that underwent surgical resections. All slides of these cases were reviewed and
representative paraffin fixed tissue blocks were selected for MLH1, MSH2, MSH6 and PMS2 IHC staining. IHC
expression was categorized into five groups: no loss of expression; loss of expression of all four antibodies; combined
loss of MLH1/PMS2; combined loss of MSH2/MSH6; and isolated loss of MLH1. Pathological records of all cases
were retrieved from patient files. Result: Abnormal expression of MSI was noted in 56 cases (44.4%) among which
16 cases showed loss of nuclear expression of all markers, 34 cases showed loss of MLH1/PMS2 expression, 4 cases
showed loss of MSH2/MSH6 while only 2 cases revealed isolated loss of MLH. Personal and family history suggestive
of inherited cancer susceptibility was revealed in 11 cases most of which were associated with MSH2/MSH6 loss.
Significant association of MSI expression was found with tumor stage and personal/family history of endometrial/
colon cancer. Conclusion: A high frequency of endometrioid cancers in our study showed abnormal expression of
MSI markers, most of which depicted MLH1/PMS2 loss and were not associated with inherited cancer susceptibility.
On the other hand, a minority of cases showed loss of all MSI markers or MSH2/MSH6 loss and were significantly
associated with family/personal history of cancer. Therefore, we suggest that epigenetic changes in MLH1 locus may
be a predominant pathway of tumorigenesis in our population rather than inherited mutation of MSI genes; however
more large scale studies with genetic testing are required to validate this observation.
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Affiliation(s)
- Atif Ali Hashmi
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Ghazala Mudassir
- Department of Pathology, Shifa College of Medicine, Islamabad, Pakistan
| | | | - Muhammad Irfan
- Department of Statistics, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Huda Asif
- Medical Student, CMH Institute of Medical Sciences, Multan, Pakistan
| | - Erum Yousuf Khan
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Syed Muhammad Abu Bakar
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Naveen Faridi
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
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Amos W. Flanking heterozygosity influences the relative probability of different base substitutions in humans. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191018. [PMID: 31598319 PMCID: PMC6774961 DOI: 10.1098/rsos.191018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
Understanding when, where and which mutations are mostly likely to occur impacts many areas of evolutionary biology, from genetic diseases to phylogenetic reconstruction. Africans and non-African humans differ in the mutability of different triplet base combinations. Africans and non-Africans also differ in mutation rate, possibly because heterozygosity is mutagenic, such that diversity lost when humans expanded out of Africa also lowered the mutation rate. I show that these phenomena are linked: as flanking heterozygosity increases, some triplets become progressively more mutable while others become less so. Africans and non-African show near-identical patterns of dependence on heterozygosity. Thus, the striking differences in triplet mutation frequency between Africans and non-Africans, at least in part, seem to be an emergent property, driven by the way changes in heterozygosity 'out of Africa' have differentially impacted the mutability of different triplets. As heterozygosity decreased, the mutation spectrum outside Africa became enriched for triplet mutations that are favoured by low heterozygosity while those favoured by high heterozygosity became relatively rarer.
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58
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Natali F, Rancati G. The Mutator Phenotype: Adapting Microbial Evolution to Cancer Biology. Front Genet 2019; 10:713. [PMID: 31447882 PMCID: PMC6691094 DOI: 10.3389/fgene.2019.00713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 07/05/2019] [Indexed: 01/07/2023] Open
Abstract
The mutator phenotype hypothesis was postulated almost 40 years ago to reconcile the observation that while cancer cells display widespread mutational burden, acquisition of mutations in non-transformed cells is a rare event. Moreover, it also suggested that cancer evolution could be fostered by increased genome instability. Given the evolutionary conservation throughout the tree of life and the genetic tractability of model organisms, yeast and bacterial species pioneered studies to dissect the functions of genes required for genome maintenance (caretaker genes) or for cell growth control (gatekeeper genes). In this review, we first provide an overview of what we learned from model organisms about the roles of these genes and the genome instability that arises as a consequence of their dysregulation. We then discuss our current understanding of how mutator phenotypes shape the evolution of bacteria and yeast species. We end by bringing clinical evidence that lessons learned from single-cell organisms can be applied to tumor evolution.
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Affiliation(s)
- Federica Natali
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Giulia Rancati
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
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AbdelGawwad MR, Marić A, Al-Ghamdi AA, Hatamleh AA. Interactome Analysis and Docking Sites of MutS Homologs Reveal New Physiological Roles in Arabidopsis thaliana. Molecules 2019; 24:molecules24132493. [PMID: 31288414 PMCID: PMC6651420 DOI: 10.3390/molecules24132493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 11/16/2022] Open
Abstract
Due to their sedentary lifestyle, plants are constantly exposed to different stress stimuli. Stress comes in variety of forms where factors like radiation, free radicals, “replication errors, polymerase slippage”, and chemical mutagens result in genotoxic or cytotoxic damage. In order to face “the base oxidation or DNA replication stress”, plants have developed many sophisticated mechanisms. One of them is the DNA mismatch repair (MMR) pathway. The main part of the MMR is the MutS homologue (MSH) protein family. The genome of Arabidopsis thaliana encodes at least seven homologues of the MSH family: AtMSH1, AtMSH2, AtMSH3, AtMSH4, AtMSH5, AtMSH6, and AtMSH7. Despite their importance, the functions of AtMSH homologs have not been investigated. In this work, bioinformatics tools were used to obtain a better understanding of MSH-mediated DNA repair mechanisms in Arabidopsis thaliana and to understand the additional biological roles of AtMSH family members. In silico analysis, including phylogeny tracking, prediction of 3D structure, interactome analysis, and docking site prediction, suggested interactions with proteins were important for physiological development of A. thaliana. The MSH homologs extensively interacted with both TIL1 and TIL2 (DNA polymerase epsilon catalytic subunit), proteins involved in cell fate determination during plant embryogenesis and involved in flowering time repression. Additionally, interactions with the RECQ protein family (helicase enzymes) and proteins of nucleotide excision repair pathway were detected. Taken together, the results presented here confirm the important role of AtMSH proteins in mismatch repair and suggest important new physiological roles.
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Affiliation(s)
- Mohamed Ragab AbdelGawwad
- Genetics and Bioengineering, Faculty of Engineering and Natural Sciences, International University of Sarajevo, 71210 Sarajevo, Bosnia and Herzegovina.
| | - Aida Marić
- Centre for Research in Agricultural Genomics, UAB-Edifici CRAG, Cerdanyola, 08193 Barcelona, Spain
| | - Abdullah Ahmed Al-Ghamdi
- Department of Botany and Microbiology, College of Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Ashraf A Hatamleh
- Department of Botany and Microbiology, College of Sciences, King Saud University, Riyadh 11451, Saudi Arabia
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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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Immunohistochemical expression of mismatch repair proteins (MSH2, MSH6, MLH1, and PMS2) in prostate cancer: correlation with grade groups (WHO 2016) and ERG and PTEN status. Virchows Arch 2019; 475:223-231. [DOI: 10.1007/s00428-019-02591-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/05/2019] [Accepted: 06/03/2019] [Indexed: 10/26/2022]
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Camuzi D, de Amorim ÍSS, Ribeiro Pinto LF, Oliveira Trivilin L, Mencalha AL, Soares Lima SC. Regulation Is in the Air: The Relationship between Hypoxia and Epigenetics in Cancer. Cells 2019; 8:cells8040300. [PMID: 30939818 PMCID: PMC6523720 DOI: 10.3390/cells8040300] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 12/12/2022] Open
Abstract
Hypoxia is an inherent condition of tumors and contributes to cancer development and progression. Hypoxia-inducible factors (HIFs) are the major transcription factors involved in response to low O2 levels, orchestrating the expression of hundreds of genes involved in cancer hallmarks’ acquisition and modulation of epigenetic mechanisms. Epigenetics refers to inheritable mechanisms responsible for regulating gene expression, including genes involved in the hypoxia response, without altering the sequence of DNA bases. The main epigenetic mechanisms are DNA methylation, non-coding RNAs, and histone modifications. These mechanisms are highly influenced by cell microenvironment, such as O2 levels. The balance and interaction between these pathways is essential for homeostasis and is directly linked to cellular metabolism. Some of the major players in the regulation of HIFs, such as prolyl hydroxylases, DNA methylation regulators, and histone modifiers require oxygen as a substrate, or have metabolic intermediates as cofactors, whose levels are altered during hypoxia. Furthermore, during pathological hypoxia, HIFs’ targets as well as alterations in epigenetic patterns impact several pathways linked to tumorigenesis, such as proliferation and apoptosis, among other hallmarks. Therefore, this review aims to elucidate the intricate relationship between hypoxia and epigenetic mechanisms, and its crucial impact on the acquisition of cancer hallmarks.
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Affiliation(s)
- Diego Camuzi
- Programa de Carcinogênese Molecular, Instituto Nacional de Câncer, Rio de Janeiro CEP 20231-050, Brazil.
| | - Ísis Salviano Soares de Amorim
- Laboratório de Biologia do Câncer (LABICAN), Departamento de Biofisica e Biometria (DBB), Instituto de Biologia Roberto Alcântara Gomes (IBRAG), Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro CEP 20511-010, Brazil.
| | - Luis Felipe Ribeiro Pinto
- Programa de Carcinogênese Molecular, Instituto Nacional de Câncer, Rio de Janeiro CEP 20231-050, Brazil.
| | - Leonardo Oliveira Trivilin
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal do Espírito Santo (UFES), Espírito Santo CEP 29500-000, Brazil.
| | - André Luiz Mencalha
- Laboratório de Biologia do Câncer (LABICAN), Departamento de Biofisica e Biometria (DBB), Instituto de Biologia Roberto Alcântara Gomes (IBRAG), Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro CEP 20511-010, Brazil.
| | - Sheila Coelho Soares Lima
- Programa de Carcinogênese Molecular, Instituto Nacional de Câncer, Rio de Janeiro CEP 20231-050, Brazil.
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Pilzecker B, Jacobs H. Mutating for Good: DNA Damage Responses During Somatic Hypermutation. Front Immunol 2019; 10:438. [PMID: 30915081 PMCID: PMC6423074 DOI: 10.3389/fimmu.2019.00438] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/19/2019] [Indexed: 11/13/2022] Open
Abstract
Somatic hypermutation (SHM) of immunoglobulin (Ig) genes plays a key role in antibody mediated immunity. SHM in B cells provides the molecular basis for affinity maturation of antibodies. In this way SHM is key in optimizing antibody dependent immune responses. SHM is initiated by targeting the Activation-Induced Cytidine Deaminase (AID) to rearranged V(D)J and switch regions of Ig genes. The mutation rate of this programmed mutagenesis is ~10-3 base pairs per generation, a million-fold higher than the non-AID targeted genome of B cells. AID is a processive enzyme that binds single-stranded DNA and deaminates cytosines in DNA. Cytosine deamination generates highly mutagenic deoxy-uracil (U) in the DNA of both strands of the Ig loci. Mutagenic processing of the U by the DNA damage response generates the entire spectrum of base substitutions characterizing SHM at and around the initial U lesion. Starting from the U as a primary lesion, currently five mutagenic DNA damage response pathways have been identified in generating a well-defined SHM spectrum of C/G transitions, C/G transversions, and A/T mutations around this initial lesion. These pathways include (1) replication opposite template U generates transitions at C/G, (2) UNG2-dependent translesion synthesis (TLS) generates transversions at C/G, (3) a hybrid pathway comprising non-canonical mismatch repair (ncMMR) and UNG2-dependent TLS generates transversions at C/G, (4) ncMMR generates mutations at A/T, and (5) UNG2- and PCNA Ubiquitination (PCNA-Ub)-dependent mutations at A/T. Furthermore, specific strand-biases of SHM spectra arise as a consequence of a biased AID targeting, ncMMR, and anti-mutagenic repriming. Here, we review mammalian SHM with special focus on the mutagenic DNA damage response pathways involved in processing AID induced Us, the origin of characteristic strand biases, and relevance of the cell cycle.
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Affiliation(s)
| | - Heinz Jacobs
- Division of Tumor Biology & Immunology, The Netherlands Cancer Institute, Amsterdam, Netherlands
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64
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Kwan AK, Um CY, Rutherford RE, Seabrook ME, Barry EL, Fedirko V, Baron JA, Bostick RM. Effects of vitamin D and calcium on expression of MSH2 and transforming growth factors in normal-appearing colorectal mucosa of sporadic colorectal adenoma patients: A randomized clinical trial. Mol Carcinog 2018; 58:511-523. [PMID: 30499618 DOI: 10.1002/mc.22945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 09/24/2018] [Accepted: 11/22/2018] [Indexed: 12/14/2022]
Abstract
Abnormal expression of the DNA mismatch repair protein MSH2 and autocrine/paracrine transforming growth factors TGFα (growth promoter) and TGFβ1 (growth inhibitor) is common during colorectal carcinogenesis. To estimate vitamin D and calcium effects on these biomarkers in the normal-appearing colorectal mucosa of sporadic colorectal adenoma patients, we conducted a pilot, randomized, double-blinded, placebo-controlled, modified 2 × 2 factorial chemoprevention clinical trial (N = 104) of supplemental vitamin D3 (1000 IU daily) and calcium (1200 mg daily), alone and in combination, versus placebo over 1 year. The expression of the three biomarkers and Ki-67/mib-1 in colorectal crypts in biopsies of normal-appearing rectal mucosa were detected using automated immunohistochemistry and quantified using image analysis. In the vitamin D3 and vitamin D3 plus calcium groups, relative to their reference groups, in the upper 40% (differentiation zone) of crypts, it was estimated that, respectively, the MSH2/mib-1 ratio increased by 47% (P = 0.14) and 62% (P = 0.08), TGFβ1 expression increased by 41% (P = 0.25) and 78% (P = 0.14), and the TGFα/TGFβ1 ratio decreased by 25% (P = 0.31) and 44% (P = 0.13). Although not statistically significant, these results support further research into (i) whether supplemental vitamin D3 , alone or in combination with calcium, may increase DNA mismatch repair relative to proliferation, increase TGFβ1 expression, and decrease autocrine/paracrine growth promotion relative to growth inhibition in the colorectal epithelium, all hypothesized to reduce risk for colorectal carcinogenesis; and (ii) the expression of MSH2 relative to mib-1, TGFβ1 alone, and TGFα relative to TGFβ1 in the normal-appearing rectal mucosa as potential modifiable, pre-neoplastic markers of risk for colorectal neoplasms.
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Affiliation(s)
- Albert K Kwan
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Caroline Y Um
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Robin E Rutherford
- Division of Digestive Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia
| | | | - Elizabeth L Barry
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | - Veronika Fedirko
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.,Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - John A Baron
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.,Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.,University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Roberd M Bostick
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.,Winship Cancer Institute, Emory University, Atlanta, Georgia
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65
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An altered gene expression profile in tyramine-exposed intestinal cell cultures supports the genotoxicity of this biogenic amine at dietary concentrations. Sci Rep 2018; 8:17038. [PMID: 30451877 PMCID: PMC6242974 DOI: 10.1038/s41598-018-35125-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/31/2018] [Indexed: 01/06/2023] Open
Abstract
Tyramine, histamine and putrescine are the most commonly detected and most abundant biogenic amines (BA) in food. The consumption of food with high concentrations of these BA is discouraged by the main food safety agencies, but legal limits have only been set for histamine. The present work reports a transcriptomic investigation of the oncogenic potential of the above-mentioned BA, as assessed in the HT29 human intestinal epithelial cell line. Tyramine had a greater effect on the expression of genes involved in tumorigenesis than did histamine or putrescine. Since some of the genes that showed altered expression in tyramine-exposed cells are involved in DNA damage and repair, the effect of this BA on the expression of other genes involved in the DNA damage response was investigated. The results suggest that tyramine might be genotoxic for intestinal cells at concentrations easily found in BA-rich food. Moreover, a role in promoting intestinal cancer cannot be excluded.
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66
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Abstract
DNA mismatch repair (MMR) is an evolutionally conserved genome maintenance pathway and is well known for its role in maintaining replication fidelity by correcting biosynthetic errors generated during DNA replication. However, recent studies have shown that MMR preferentially protects actively transcribed genes from mutation during both DNA replication and transcription. This review describes the recent discoveries in this area. Potential mechanisms by which MMR safeguards actively transcribed genes are also discussed.
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Affiliation(s)
- Yaping Huang
- Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, 100084, China
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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67
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Gan Y, Li Y, Li T, Shu G, Yin G. CCNA2 acts as a novel biomarker in regulating the growth and apoptosis of colorectal cancer. Cancer Manag Res 2018; 10:5113-5124. [PMID: 30464611 PMCID: PMC6217169 DOI: 10.2147/cmar.s176833] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Colorectal cancer (CRC) is considered to be the most prevalent malignant tumors that contribute to high cancer-related mortality. However, the signaling pathways involved in CRC and CRC-driven genes are largely unknown. We seek to discover a novel biomarker in CRC. MATERIALS AND METHODS All clinical CRC samples (n=33) were from Xiangya Hospital. We first selected CCNA2 by integrated bioinformatics analysis of four GSE databases. Next, the expression of CCNA2 in tissues and cell lines was verified by quantitative real-time PCR. The effects of CCNA2 on cell growth, proliferation, cell cycle, and apoptosis were examined by in vitro assays. RESULTS We identified 498 shared DEGs (294 upregulated and 204 downregulated), and the top ten hub genes were selected by integrated analysis. These hub genes were significantly overexpressed in CRC samples and were positively correlated. Our data revealed that the expression of CCNA2 in CRC tissues is higher than that in normal tissues. The CCNA2 knockdown could significantly suppress CRC cell growth by impairing cell cycle progression and inducing cell apoptosis. CONCLUSION CCNA2, as a novel oncogenic gene, plays a role in regulating cancer cell growth and apoptosis. It could be used as a new biomarker for diagnosis and therapy in CRC.
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Affiliation(s)
- Yaqi Gan
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, China,
| | - Yimin Li
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, China,
| | - Tong Li
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, China,
| | - Guang Shu
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, China,
| | - Gang Yin
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, China,
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68
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Graham WJ, Putnam CD, Kolodner RD. The properties of Msh2-Msh6 ATP binding mutants suggest a signal amplification mechanism in DNA mismatch repair. J Biol Chem 2018; 293:18055-18070. [PMID: 30237169 PMCID: PMC6254361 DOI: 10.1074/jbc.ra118.005439] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 09/17/2018] [Indexed: 11/30/2022] Open
Abstract
DNA mismatch repair (MMR) corrects mispaired DNA bases and small insertion/deletion loops generated by DNA replication errors. After binding a mispair, the eukaryotic mispair recognition complex Msh2–Msh6 binds ATP in both of its nucleotide-binding sites, which induces a conformational change resulting in the formation of an Msh2–Msh6 sliding clamp that releases from the mispair and slides freely along the DNA. However, the roles that Msh2–Msh6 sliding clamps play in MMR remain poorly understood. Here, using Saccharomyces cerevisiae, we created Msh2 and Msh6 Walker A nucleotide–binding site mutants that have defects in ATP binding in one or both nucleotide-binding sites of the Msh2–Msh6 heterodimer. We found that these mutations cause a complete MMR defect in vivo. The mutant Msh2–Msh6 complexes exhibited normal mispair recognition and were proficient at recruiting the MMR endonuclease Mlh1–Pms1 to mispaired DNA. At physiological (2.5 mm) ATP concentration, the mutant complexes displayed modest partial defects in supporting MMR in reconstituted Mlh1–Pms1-independent and Mlh1–Pms1-dependent MMR reactions in vitro and in activation of the Mlh1–Pms1 endonuclease and showed a more severe defect at low (0.1 mm) ATP concentration. In contrast, five of the mutants were completely defective and one was mostly defective for sliding clamp formation at high and low ATP concentrations. These findings suggest that mispair-dependent sliding clamp formation triggers binding of additional Msh2–Msh6 complexes and that further recruitment of additional downstream MMR proteins is required for signal amplification of mispair binding during MMR.
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Affiliation(s)
| | - Christopher D Putnam
- From the Ludwig Institute for Cancer Research San Diego,; Departments of Medicine and
| | - Richard D Kolodner
- From the Ludwig Institute for Cancer Research San Diego,; Cellular and Molecular Medicine,; Moores-UCSD Cancer Center, and; Institute of Genomic Medicine, University of California School of Medicine, San Diego, La Jolla, California 92093-0669.
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69
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Bhattacharjee S, Nandi S. Rare Genetic Diseases with Defects in DNA Repair: Opportunities and Challenges in Orphan Drug Development for Targeted Cancer Therapy. Cancers (Basel) 2018; 10:E298. [PMID: 30200453 PMCID: PMC6162646 DOI: 10.3390/cancers10090298] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 12/22/2022] Open
Abstract
A better understanding of mechanistic insights into genes and enzymes implicated in rare diseases provide a unique opportunity for orphan drug development. Advances made in identification of synthetic lethal relationships between rare disorder genes with oncogenes and tumor suppressor genes have brought in new anticancer therapeutic opportunities. Additionally, the rapid development of small molecule inhibitors against enzymes that participate in DNA damage response and repair has been a successful strategy for targeted cancer therapeutics. Here, we discuss the recent advances in our understanding of how many rare disease genes participate in promoting genome stability. We also summarize the latest developments in exploiting rare diseases to uncover new biological mechanisms and identify new synthetic lethal interactions for anticancer drug discovery that are in various stages of preclinical and clinical studies.
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Affiliation(s)
| | - Saikat Nandi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA.
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70
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Stringer JM, Winship A, Liew SH, Hutt K. The capacity of oocytes for DNA repair. Cell Mol Life Sci 2018; 75:2777-2792. [PMID: 29748894 PMCID: PMC11105623 DOI: 10.1007/s00018-018-2833-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/27/2018] [Accepted: 05/02/2018] [Indexed: 12/18/2022]
Abstract
Female fertility and offspring health are critically dependent on the maintenance of an adequate supply of high-quality oocytes. Like somatic cells, oocytes are subject to a variety of different types of DNA damage arising from endogenous cellular processes and exposure to exogenous genotoxic stressors. While the repair of intentionally induced DNA double strand breaks in gametes during meiotic recombination is well characterised, less is known about the ability of oocytes to repair pathological DNA damage and the relative contribution of DNA repair to oocyte quality is not well defined. This review will discuss emerging data suggesting that oocytes are in fact capable of efficient DNA repair and that DNA repair may be an important mechanism for ensuring female fertility, as well as the transmission of high-quality genetic material to subsequent generations.
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Affiliation(s)
- Jessica M Stringer
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Amy Winship
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Seng H Liew
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Karla Hutt
- Ovarian Biology Laboratory, Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
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71
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Identification of Exo1-Msh2 interaction motifs in DNA mismatch repair and new Msh2-binding partners. Nat Struct Mol Biol 2018; 25:650-659. [PMID: 30061603 DOI: 10.1038/s41594-018-0092-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/14/2018] [Indexed: 02/07/2023]
Abstract
Eukaryotic DNA mismatch repair (MMR) involves both exonuclease 1 (Exo1)-dependent and Exo1-independent pathways. We found that the unstructured C-terminal domain of Saccharomyces cerevisiae Exo1 contains two MutS homolog 2 (Msh2)-interacting peptide (SHIP) boxes downstream from the MutL homolog 1 (Mlh1)-interacting peptide (MIP) box. These three sites were redundant in Exo1-dependent MMR in vivo and could be replaced by a fusion protein between an N-terminal fragment of Exo1 and Msh6. The SHIP-Msh2 interactions were eliminated by the msh2M470I mutation, and wild-type but not mutant SHIP peptides eliminated Exo1-dependent MMR in vitro. We identified two S. cerevisiae SHIP-box-containing proteins and three candidate human SHIP-box-containing proteins. One of these, Fun30, had a small role in Exo1-dependent MMR in vivo. The Remodeling of the Structure of Chromatin (Rsc) complex also functioned in both Exo1-dependent and Exo1-independent MMR in vivo. Our results identified two modes of Exo1 recruitment and a peptide module that mediates interactions between Msh2 and other proteins, and they support a model in which Exo1 functions in MMR by being tethered to the Msh2-Msh6 complex.
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72
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Ye M, He Z, Dai W, Li Z, Chen X, Liu J. A TOP2A-derived cancer panel drives cancer progression in papillary renal cell carcinoma. Oncol Lett 2018; 16:4169-4178. [PMID: 30214555 DOI: 10.3892/ol.2018.9179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 02/23/2018] [Indexed: 02/07/2023] Open
Abstract
The aim of the present study was to investigate the function of the DNA topoisomerase IIα (TOP2A) gene and its associated genes in the progression of papillary renal cell carcinoma (PRCC). Online cancer databases, including cBioportal, Oncomine, OncoLnc and Search Tool for the Retrieval of Interacting Genes/Proteins were used to analyze the TOP2A gene expression profile, function and regulation network in PRCC. The genes that were significantly co-expressed or mutually exclusively expressed with TOP2A were identified. The genes co-expressed with TOP2A were defined as a 'TOP2A-cancer panel', which cooperatively promotes PRCC progression. This gene panel performed well in predicting the prognosis of PRCC. In addition, the TOP2A-cancer panel significantly affected the outcome of PRCC compared with clear cell renal cell carcinoma (CCRCC). The protein-protein interaction network of all genes associated with TOP2A was also generated. This interaction network may provide foundation for the additional investigation of TOP2A. Integrative understating of the TOP2A-cancer panel may result in a novel avenue for treatment intervention in PRCC.
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Affiliation(s)
- Mushi Ye
- Department of Urological Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
| | - Zhuobin He
- Department of Urological Surgery, Da Lang Hospital of Dongguan, Dongguan, Guangdong 523770, P.R. China
| | - Wei Dai
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
| | - Zhuo Li
- Department of Urological Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
| | - Xiaojun Chen
- Department of Urological Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
| | - Jianjun Liu
- Department of Urological Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
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Abstract
Lynch Syndrome (LS) is the most common dominantly inherited colorectal cancer (CRC) predisposition and is caused by a heterozygous germline defect in one of the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, or PMS2. High microsatellite instability (MSI-H) and loss of MMR protein expression in tumours reflecting a defective MMR are indicators for LS, as well as a positive family history of early onset CRC. MSH2 and MSH6 form a major functional heterodimer, and MSH3 is an alternative binding partner for MSH2. So far, the role of germline MSH3 variants remains unclear, as to our knowledge heterozygous truncating variants are not regarded causative for LS, but were detected in patients with CRC, and recently biallelic MSH3 defects have been identified in two patients with adenomatous polyposis. By gene screening we investigated the role of MSH3 in 11 LS patients with truncating MSH6 germline variants and an unexplained MSH2 protein loss in their corresponding MSI-H tumours. We report the first two LS patients harbouring heterozygous germline variants c.1035del and c.2732T>G in MSH3 coincidentally with truncating variants in MSH6. In the patient with truncating germline variants in MSH3 and MSH6, two additional somatic second hits in both genes abrogate all binding partners for the MSH2 protein which might subsequently be degraded. The clinical relevance of MSH3 germline variants is currently under re-evaluation, and heterozygous MSH3 defects alone do not seem to induce a LS phenotype, but might aggravate the MSH6 phenotype in affected family members.
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Bhattacharjee S, Nandi S. Synthetic lethality in DNA repair network: A novel avenue in targeted cancer therapy and combination therapeutics. IUBMB Life 2018; 69:929-937. [PMID: 29171189 DOI: 10.1002/iub.1696] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/05/2017] [Indexed: 11/06/2022]
Abstract
Synthetic lethality refers to a lethal phenotype that results from the simultaneous disruptions of two genes, while the disruption of either gene alone is viable. Many DNA double strand break repair (DSBR) genes have synthetic lethal relationships with oncogenes and tumor suppressor genes, which can be exploited for targeted cancer therapy, an approach referred to as combination therapy. DNA double-strand breaks (DSBs) are one of the most toxic lesions to a cell and can be repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). HR and NHEJ genes are particularly attractive targets for cancer therapy because these genes have altered expression patterns in cancer cells when compared with normal cells and these genetic abnormalities can be targeted for selectively killing cancer cells. Here, we review recent advances in the development of small molecule inhibitors against HR and NHEJ genes to induce synthetic lethality and address the future directions and clinical relevance of this approach. © 2017 IUBMB Life, 69(12):929-937, 2017.
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Affiliation(s)
| | - Saikat Nandi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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75
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Halabi A, Fuselier KTB, Grabczyk E. GAA•TTC repeat expansion in human cells is mediated by mismatch repair complex MutLγ and depends upon the endonuclease domain in MLH3 isoform one. Nucleic Acids Res 2018; 46:4022-4032. [PMID: 29529236 PMCID: PMC5934671 DOI: 10.1093/nar/gky143] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/15/2018] [Indexed: 12/12/2022] Open
Abstract
DNA repeat expansion underlies dozens of progressive neurodegenerative disorders. While the mechanisms driving repeat expansion are not fully understood, increasing evidence suggests a central role for DNA mismatch repair. The mismatch repair recognition complex MutSβ (MSH2-MSH3) that binds mismatched bases and/or insertion/deletion loops has previously been implicated in GAA•TTC, CAG•CTG and CGG•CCG repeat expansion, suggesting a shared mechanism. MutSβ has been studied in a number of models, but the contribution of subsequent steps mediated by the MutL endonuclease in this pathway is less clear. Here we show that MutLγ (MLH1-MLH3) is the MutL complex responsible for GAA•TTC repeat expansion. Lentiviral expression of shRNA targeting MutL nuclease components MLH1, PMS2, and MLH3 revealed that reduced expression of MLH1 or MLH3 reduced the repeat expansion rate in a human Friedreich ataxia cell model, while targeting PMS2 did not. Using splice-switching oligonucleotides we show that MLH3 isoform 1 is active in GAA•TTC repeat expansion while the nuclease-deficient MLH3 isoform 2 is not. MLH3 isoform switching slowed repeat expansion in both model cells and FRDA patient fibroblasts. Our work indicates a specific and active role for MutLγ in the expansion process and reveals plausible targets for disease-modifying therapies.
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Affiliation(s)
- Anasheh Halabi
- Division of Neurology, Department of Neurosciences, University of California, San Diego, CA 92103, USA
| | - Kayla T B Fuselier
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Ed Grabczyk
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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de Barros AC, Takeda AAS, Dreyer TR, Velazquez-Campoy A, Kobe B, Fontes MRM. DNA mismatch repair proteins MLH1 and PMS2 can be imported to the nucleus by a classical nuclear import pathway. Biochimie 2017; 146:87-96. [PMID: 29175432 DOI: 10.1016/j.biochi.2017.11.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/22/2017] [Indexed: 01/11/2023]
Abstract
MLH1 and PMS2 proteins form the MutLα heterodimer, which plays a major role in DNA mismatch repair (MMR) in humans. Mutations in MMR-related proteins are associated with cancer, especially with colon cancer. The N-terminal region of MutLα comprises the N-termini of PMS2 and MLH1 and, similarly, the C-terminal region of MutLα is composed by the C-termini of PMS2 and MLH1, and the two are connected by linker region. The nuclear localization sequences (NLSs) necessary for the nuclear transport of the two proteins are found in this linker region. However, the exact NLS sequences have been controversial, with different sequences reported, particularly for MLH1. The individual components are not imported efficiently, presumably due to their C-termini masking their NLSs. In order to gain insights into the nuclear transport of these proteins, we solved the crystal structures of importin-α bound to peptides corresponding to the supposed NLSs of MLH1 and PMS2 and performed isothermal titration calorimetry to study their binding affinities. Both putative MLH1 and PMS2 NLSs can bind to importin-α as monopartite NLSs, which is in agreement with some previous studies. However, MLH1-NLS has the highest affinity measured by a natural NLS peptide, suggesting a major role of MLH1 protein in nuclear import compared to PMS2. Finally, the role of MLH1 and PMS2 in the nuclear transport of the MutLα heterodimer is discussed.
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Affiliation(s)
- Andrea C de Barros
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Agnes A S Takeda
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Thiago R Dreyer
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint-Unit IQFR-CSIC-BIFI, University of Zaragoza, Zaragoza, Spain; Dep. of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain; Fundacion ARAID, Government of Aragon, Zaragoza, Spain
| | - Boštjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Marcos R M Fontes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil.
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Forsström LM, Sumi K, Mäkinen MJ, Oh JE, Herva R, Kleihues P, Ohgaki H, Aaltonen LA. Germline MSH6 Mutation in a Patient With Two Independent Primary Glioblastomas. J Neuropathol Exp Neurol 2017; 76:848-853. [PMID: 28922847 DOI: 10.1093/jnen/nlx066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2024] Open
Abstract
We previously reported a patient who had developed 2 glioblastomas at the age of 54 and 64 years, respectively. The first glioblastoma in the right frontal lobe was treated with surgery and radiotherapy. Ten years later, the patient developed a second, left frontal glioblastoma. Discordant patterns of TP53 and PTEN mutations suggested that the second tumor was not a recurrence but an independently developed glioblastoma. To determine the molecular mechanism underlying this enigmatic case with 10-year survival, we performed whole-exome sequencing. We found that both tumors were IDH-wildtype, excluding the possibility of secondary glioblastomas that developed from a less malignant astrocytic precursor lesion. We here report that the patient carried a heterozygous germline mutation [c.3305_3306insT; p.1102-fs-insT(Gly1105/TrpfsX3)] in the MSH6 mismatch repair gene. Further sequencing revealed that in addition to the germline MSH6 mutation, the first glioblastoma showed loss of the MSH6 wild-type allele, and the second glioblastoma carried a somatic MSH6 mutation [c.1403G>A; p.Arg468His]. Our results indicate that both glioblastomas had 2 hits in the MSH6 gene, and that loss of MSH6 function was the key event in the pathogenesis of these 2 independent primary glioblastomas.
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Affiliation(s)
- Linda M Forsström
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Koichiro Sumi
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Markus J Mäkinen
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Ji Eun Oh
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Riitta Herva
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Paul Kleihues
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Hiroko Ohgaki
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Lauri A Aaltonen
- Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland; International Agency for Research on Cancer, Lyon, France; Department of Pathology, Oulu University Hospital, Oulu, Finland; Medical Faculty, University of Zurich, Zurich, Switzerland
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Proteome Stability as a Key Factor of Genome Integrity. Int J Mol Sci 2017; 18:ijms18102036. [PMID: 28937603 PMCID: PMC5666718 DOI: 10.3390/ijms18102036] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/11/2017] [Accepted: 09/19/2017] [Indexed: 12/11/2022] Open
Abstract
DNA damage is constantly produced by both endogenous and exogenous factors; DNA lesions then trigger the so-called DNA damaged response (DDR). This is a highly synchronized pathway that involves recognition, signaling and repair of the damage. Failure to eliminate DNA lesions is associated with genome instability, a driving force in tumorigenesis. Proteins carry out the vast majority of cellular functions and thus proteome quality control (PQC) is critical for the maintenance of cellular functionality. PQC is assured by the proteostasis network (PN), which under conditions of proteome instability address the triage decision of protein fold, hold, or degrade. Key components of the PN are the protein synthesis modules, the molecular chaperones and the two main degradation machineries, namely the autophagy-lysosome and the ubiquitin-proteasome pathways; also, part of the PN are a number of stress-responsive cellular sensors including (among others) heat shock factor 1 (Hsf1) and the nuclear factor erythroid 2-related factor 2 (Nrf2). Nevertheless, the lifestyle- and/or ageing-associated gradual accumulation of stressors results in increasingly damaged and unstable proteome due to accumulation of misfolded proteins and/or protein aggregates. This outcome may then increase genomic instability due to reduced fidelity in processes like DNA replication or repair leading to various age-related diseases including cancer. Herein, we review the role of proteostatic machineries in nuclear genome integrity and stability, as well as on DDR responses.
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Li P, Xiao Z, Braciak TA, Ou Q, Chen G, Oduncu FS. Systematic immunohistochemical screening for mismatch repair and ERCC1 gene expression from colorectal cancers in China: Clinicopathological characteristics and effects on survival. PLoS One 2017; 12:e0181615. [PMID: 28767665 PMCID: PMC5540538 DOI: 10.1371/journal.pone.0181615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 07/05/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND We performed a systematic screening of colorectal cancer (CRC) tissues to investigate whether mismatch repair (MMR) status and ERCC1 protein expression could be predictive of clinical outcomes for these patients following the recommendation of The Evaluation of Genomic Applications in Practice of Prevention (EGAPP). METHODS The expression of four MMR genes and ERCC1 were assessed by immunohistochemistry (IHC) from cancer tissue samples of 2233 consecutive CRC patients. RESULTS We observed that most CRC patients with a proficient MMR (pMMR) status tended to have simultaneous ERCC1 protein expression (P< 0.001). Stage III CRC patients with deficient MMR (dMMR) had higher prognoses than the same stage patients with pMMR (DFS: 74% vs 65%, P = 0.04; OS: 79% vs 69%, P = 0.04). Here, dMMR is also associated with poorer survival for stage II patients after chemotherapy (DFS: 66% vs 78%, P = 0.04). Stage II and III patients that were shown to express ERCC1 protein had higher DFS and OS than those that were deficient in expression (stage II, DFS: 83% vs 70%, P = 0.006; OS 85% vs 73%, P = 0.02. Stage III, DFS: 67% vs56%, P = 0.03; OS: 71% vs 57%, P = 0.04). CONCLUSIONS Our results indicate that dMMR appeared to predictive of a survival benefit for stage III CRC patients. We also found the determination of ERCC1 expression to be useful for predicting DFS or OS for stage II and III CRC patients. In addition, the expression of MMR genes and ERCC1 showed a significant relationship.
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Affiliation(s)
- Pan Li
- Department of Hematology and Oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
| | - Zhitao Xiao
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Todd A. Braciak
- Department of Hematology and Oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
| | - Qingjian Ou
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
- * E-mail: (FSO); (GC); (QJO)
| | - Gong Chen
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
- * E-mail: (FSO); (GC); (QJO)
| | - Fuat S. Oduncu
- Department of Hematology and Oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
- * E-mail: (FSO); (GC); (QJO)
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DNA mismatch repair and its many roles in eukaryotic cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:174-187. [PMID: 28927527 DOI: 10.1016/j.mrrev.2017.07.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/01/2017] [Accepted: 07/06/2017] [Indexed: 02/06/2023]
Abstract
DNA mismatch repair (MMR) is an important DNA repair pathway that plays critical roles in DNA replication fidelity, mutation avoidance and genome stability, all of which contribute significantly to the viability of cells and organisms. MMR is widely-used as a diagnostic biomarker for human cancers in the clinic, and as a biomarker of cancer susceptibility in animal model systems. Prokaryotic MMR is well-characterized at the molecular and mechanistic level; however, MMR is considerably more complex in eukaryotic cells than in prokaryotic cells, and in recent years, it has become evident that MMR plays novel roles in eukaryotic cells, several of which are not yet well-defined or understood. Many MMR-deficient human cancer cells lack mutations in known human MMR genes, which strongly suggests that essential eukaryotic MMR components/cofactors remain unidentified and uncharacterized. Furthermore, the mechanism by which the eukaryotic MMR machinery discriminates between the parental (template) and the daughter (nascent) DNA strand is incompletely understood and how cells choose between the EXO1-dependent and the EXO1-independent subpathways of MMR is not known. This review summarizes recent literature on eukaryotic MMR, with emphasis on the diverse cellular roles of eukaryotic MMR proteins, the mechanism of strand discrimination and cross-talk/interactions between and co-regulation of MMR and other DNA repair pathways in eukaryotic cells. The main conclusion of the review is that MMR proteins contribute to genome stability through their ability to recognize and promote an appropriate cellular response to aberrant DNA structures, especially when they arise during DNA replication. Although the molecular mechanism of MMR in the eukaryotic cell is still not completely understood, increased used of single-molecule analyses in the future may yield new insight into these unsolved questions.
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Hashmi AA, Ali R, Hussain ZF, Faridi N, Khan EY, Bakar SMA, Edhi MM, Khan M. Mismatch repair deficiency screening in colorectal carcinoma by a four-antibody immunohistochemical panel in Pakistani population and its correlation with histopathological parameters. World J Surg Oncol 2017. [PMID: 28651545 PMCID: PMC5485685 DOI: 10.1186/s12957-017-1158-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Background Microsatellite instability (MSI) operates as the second major pathway in the colorectal carcinogenesis. Although genetic testing remains the gold standard for the detection of MSI, the College of American Pathologists (CAP) recommends an initial immunohistochemical workup with a four-antibody panel (MLH1, PMS2, MSH2, and MSH6) to screen for a defective mismatch repair system. An increased trend towards young age colorectal carcinoma (CRC) has been noticed in our population over recent years; however, neither screening for MSI by immunohistochemistry (IHC)/genetic testing was done nor were its morphological features studied. We aimed to determine the frequency of mismatch repair deficiency (dMMR) by loss of IHC expression of the aforementioned enzymes in CRC patients and its correlatation with clinicopathologic parameters. Methods This was a retrospective study conducted at Liaquat National Hospital, Karachi, between 2012 and 2015. A total of 100 cases of CRC were included in the study that underwent surgical resection. IHC stains using antibodies MLH1, PMS2, MSH2, and MSH6 were performed by DAKO EnVision method on representative tissue blocks. The results were interpreted by senior histopathologists and correlated with clinico-pathological parameters. Results A total of 100 cases of CRC were studied that included 51 males and 49 females. Thirty-four percent (n = 34) of the patients showed loss of IHC staining for MMR markers. Combined loss of expression for MLH1/PMS2 were observed in 16% (n = 16) of the cases. Loss of MSH2/MSH6 were seen in 6% (n = 6) of the cases. Loss of expression for all markers were noted in 7% (n = 7) of the cases. There were 5% (n = 5) of the cases that showed isolated loss of MLH1 only. The tumors with dMMR status were significantly associated with right-sided location (p = 0.013), exhibited intra-tumoral lymphocytosis (p = 0.007), and lymphovascular invasion (p = 0.043). No significant association was seen with gender, age, tumor stage, grade, or other morphological features. Conclusion The frequency of mismatch repair deficiency in CRC patients was found to be 34% in Pakistani population which warrants further genetic testing to exclude Lynch syndrome. Moreover, right-sided location and intra-tumoral lymphocyte count may be used to identify patients who may need further workup.
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Affiliation(s)
- Atif Ali Hashmi
- Histopathology department, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Rabia Ali
- Histopathology department, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Zubaida Fida Hussain
- Histopathology department, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Naveen Faridi
- Histopathology department, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Erum Yousuf Khan
- Histopathology department, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | | | - Muhammad Muzzammil Edhi
- Surgery department, Rhode Island Hospital and Brown University, Providence, Rhode Island, USA
| | - Mehmood Khan
- Medicine department, Dhaka University, Dhaka, Bangladesh.
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Skelly DA, Magwene PM, Meeks B, Murphy HA. Known mutator alleles do not markedly increase mutation rate in clinical Saccharomyces cerevisiae strains. Proc Biol Sci 2017; 284:20162672. [PMID: 28404772 PMCID: PMC5394658 DOI: 10.1098/rspb.2016.2672] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/17/2017] [Indexed: 11/12/2022] Open
Abstract
Natural selection has the potential to act on all phenotypes, including genomic mutation rate. Classic evolutionary theory predicts that in asexual populations, mutator alleles, which cause high mutation rates, can fix due to linkage with beneficial mutations. This phenomenon has been demonstrated experimentally and may explain the frequency of mutators found in bacterial pathogens. By contrast, in sexual populations, recombination decouples mutator alleles from beneficial mutations, preventing mutator fixation. In the facultatively sexual yeast Saccharomyces cerevisiae, segregating alleles of MLH1 and PMS1 have been shown to be incompatible, causing a high mutation rate when combined. These alleles had never been found together naturally, but were recently discovered in a cluster of clinical isolates. Here we report that the incompatible mutator allele combination only marginally elevates mutation rate in these clinical strains. Genomic and phylogenetic analyses provide no evidence of a historically elevated mutation rate. We conclude that the effect of the mutator alleles is dampened by background genetic modifiers. Thus, the relationship between mutation rate and microbial pathogenicity may be more complex than once thought. Our findings provide rare observational evidence that supports evolutionary theory suggesting that sexual organisms are unlikely to harbour alleles that increase their genomic mutation rate.
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Affiliation(s)
| | | | - Brianna Meeks
- Department of Biology, The College of William and Mary, Williamsburg, VA, USA
| | - Helen A Murphy
- Department of Biology, The College of William and Mary, Williamsburg, VA, USA
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83
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Homozygous germ-line mutation of the PMS2 mismatch repair gene: a unique case report of constitutional mismatch repair deficiency (CMMRD). BMC MEDICAL GENETICS 2017; 18:40. [PMID: 28381238 PMCID: PMC5381022 DOI: 10.1186/s12881-017-0391-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 03/06/2017] [Indexed: 12/11/2022]
Abstract
Background Constitutional mismatch repair deficiency syndrome results from bi-allelic inheritance of mutations affecting the key DNA mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. Individuals with bi-allelic mutations have a dysfunctional mismatch repair system from birth; as a result, constitutional mismatch repair deficiency syndrome is characterised by early onset malignancies. Fewer than 150 cases have been reported in the literature over the past 20 years. This is the first report of the founder PMS2 mutation - NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11 and its associated cancers in this family. Case presentation The proband is 30 years old and is alive today. She is of Pakistani ethnic origin and a product of consanguinity. She initially presented aged 24 with painless bleeding per-rectum from colorectal polyps and was referred to clinical genetics. Clinical examination revealed two café-au-lait lesions, lichen planus, and a dermoid cyst. Her sister had been diagnosed in childhood with an aggressive brain tumour followed by colorectal cancer. During follow up, the proband developed 37 colorectal adenomatous polyps, synchronous ovarian and endometrial adenocarcinomas, and ultimately a metachronous gastric adenocarcinoma. DNA sequencing of peripheral lymphocytes revealed a bi-allelic inheritance of the PMS2 mutation NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11. Ovarian tumour tissue demonstrated low microsatellite instability. To date, she has had a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and a total gastrectomy. Aspirin and oestrogen-only hormone replacement therapy provide some chemoprophylaxis and manage postmenopausal symptoms, respectively. An 18-monthly colonoscopy surveillance programme has led to the excision of three high-grade dysplastic colorectal tubular adenomatous polyps. The proband’s family pedigree displays multiple relatives with cancers including a likely case of ‘true’ Turcot syndrome. Conclusions Constitutional mismatch repair deficiency syndrome should be considered in patients who present with early onset cancer, a strong family history of cancer, and cutaneous features resembling neurofibromatosis type I. Immunohistochemistry analysis of tumour and normal tissue is sensitive and specific for identifying patients with mismatch repair deficiency and should direct DNA sequencing of lymphocytic tissue to establish a diagnosis. Microsatellite instability status appears to be of little value in identifying patients who may have constitutional mismatch repair deficiency syndrome.
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84
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Bowen N, Kolodner RD. Reconstitution of Saccharomyces cerevisiae DNA polymerase ε-dependent mismatch repair with purified proteins. Proc Natl Acad Sci U S A 2017; 114:3607-3612. [PMID: 28265089 PMCID: PMC5389320 DOI: 10.1073/pnas.1701753114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mammalian and Saccharomyces cerevisiae mismatch repair (MMR) proteins catalyze two MMR reactions in vitro. In one, mispair binding by either the MutS homolog 2 (Msh2)-MutS homolog 6 (Msh6) or the Msh2-MutS homolog 3 (Msh3) stimulates 5' to 3' excision by exonuclease 1 (Exo1) from a single-strand break 5' to the mispair, excising the mispair. In the other, Msh2-Msh6 or Msh2-Msh3 activate the MutL homolog 1 (Mlh1)-postmeiotic segregation 1 (Pms1) endonuclease in the presence of a mispair and a nick 3' to the mispair, to make nicks 5' to the mispair, allowing Exo1 to excise the mispair. DNA polymerase δ (Pol δ) is thought to catalyze DNA synthesis to fill in the gaps resulting from mispair excision. However, colocalization of the S. cerevisiae mispair recognition proteins with the replicative DNA polymerases during DNA replication has suggested that DNA polymerase ε (Pol ε) may also play a role in MMR. Here we describe the reconstitution of Pol ε-dependent MMR using S. cerevisiae proteins. A mixture of Msh2-Msh6 (or Msh2-Msh3), Exo1, RPA, RFC-Δ1N, PCNA, and Pol ε was found to catalyze both short-patch and long-patch 5' nick-directed MMR of a substrate containing a +1 (+T) mispair. When the substrate contained a nick 3' to the mispair, a mixture of Msh2-Msh6 (or Msh2-Msh3), Exo1, RPA, RFC-Δ1N, PCNA, and Pol ε was found to catalyze an MMR reaction that required Mlh1-Pms1. These results demonstrate that Pol ε can act in eukaryotic MMR in vitro.
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Affiliation(s)
- Nikki Bowen
- Ludwig Institute for Cancer Research, University of California School of Medicine, La Jolla, CA 92093-0669
| | - Richard D Kolodner
- Ludwig Institute for Cancer Research, University of California School of Medicine, La Jolla, CA 92093-0669;
- Department of Cellular and Molecular Medicine, University of California School of Medicine, La Jolla, CA 92093-0669
- Moores-University of California San Diego Cancer Center, University of California School of Medicine, La Jolla, CA 92093-0669
- Institute of Genomic Medicine, University of California School of Medicine, La Jolla, CA 92093-0669
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Li P, Xiao ZT, Braciak TA, Ou QJ, Chen G, Oduncu FS. Impact of age and mismatch repair status on survival in colorectal cancer. Cancer Med 2017; 6:975-981. [PMID: 28345223 PMCID: PMC5430087 DOI: 10.1002/cam4.1007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 01/01/2023] Open
Abstract
Previous studies have suggested that deficiencies in mismatch repair genes (dMMR) often occur in patients with colorectal cancer (CRC) and contribute to disease etiology. Here, we looked for a correlation of MMR status to disease outcomes from a large number of Chinese CRC patients stratified by the age of onset of disease. A total of 2233 CRC patients were analyzed and tissue biopsies of surgically removed tumors scored for MMR gene status. The patient distribution after classification consisted of 188 younger aged patients (20-39 years of age), 1024 middle aged patients (40-59 years of age), and 1020 older aged patients (60-85 years of age). In this analysis, the expression of four MMR genes was assessed by immunohistochemistry (IHC). We found that the young group of CRC patients with dMMR had higher overall survival (OS) than the young group of patients with proficient MMR (pMMR) (77% vs. 56%, P = 0.03). Middle-aged patients with dMMR also had higher OS than middle-aged group patients with pMMR (78% vs. 68%, P = 0.012). However, we found no statistical difference in OS between dMMR and pMMR status in the older group of patients (75% vs. 71%, P = 0.224). Finally, the middle- and older-aged group set of patients had higher OS than the young group of patients (69% vs. 71% vs. 59%, P = 0.008). These data demonstrated that the age of disease onset can be an important factor to help evaluate the prognosis of CRC when combined with the analysis of MMR status within tumor biopsied tissue.
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Affiliation(s)
- Pan Li
- Department of hematology and oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
| | - Zhi-Tao Xiao
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Todd A Braciak
- Department of hematology and oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
| | - Qing-Jian Ou
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Gong Chen
- Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Fuat S Oduncu
- Department of hematology and oncology, Medizinische Klinik und Poliklinik IV, Ludwig Maximilians University, Munich, Germany
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Control of Genome Integrity by RFC Complexes; Conductors of PCNA Loading onto and Unloading from Chromatin during DNA Replication. Genes (Basel) 2017; 8:genes8020052. [PMID: 28134787 PMCID: PMC5333041 DOI: 10.3390/genes8020052] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/21/2017] [Indexed: 11/23/2022] Open
Abstract
During cell division, genome integrity is maintained by faithful DNA replication during S phase, followed by accurate segregation in mitosis. Many DNA metabolic events linked with DNA replication are also regulated throughout the cell cycle. In eukaryotes, the DNA sliding clamp, proliferating cell nuclear antigen (PCNA), acts on chromatin as a processivity factor for DNA polymerases. Since its discovery, many other PCNA binding partners have been identified that function during DNA replication, repair, recombination, chromatin remodeling, cohesion, and proteolysis in cell-cycle progression. PCNA not only recruits the proteins involved in such events, but it also actively controls their function as chromatin assembles. Therefore, control of PCNA-loading onto chromatin is fundamental for various replication-coupled reactions. PCNA is loaded onto chromatin by PCNA-loading replication factor C (RFC) complexes. Both RFC1-RFC and Ctf18-RFC fundamentally function as PCNA loaders. On the other hand, after DNA synthesis, PCNA must be removed from chromatin by Elg1-RFC. Functional defects in RFC complexes lead to chromosomal abnormalities. In this review, we summarize the structural and functional relationships among RFC complexes, and describe how the regulation of PCNA loading/unloading by RFC complexes contributes to maintaining genome integrity.
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Alves MGO, Carta CFL, de Barros PP, Issa JS, Nunes FD, Almeida JD. Repair genes expression profile of MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers. Arch Oral Biol 2017; 73:60-65. [DOI: 10.1016/j.archoralbio.2016.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 08/16/2016] [Accepted: 09/15/2016] [Indexed: 01/15/2023]
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HuCOP1 contributes to the regulation of DNA repair in keratinocytes. Mol Cell Biochem 2016; 427:103-109. [PMID: 27995412 DOI: 10.1007/s11010-016-2901-0] [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: 10/06/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022]
Abstract
We have previously demonstrated that the E3 ligase Human Constitutive Photomorphogenic Protein (huCOP1) is expressed in human keratinocytes and negatively regulates p53. The MutS homolog 2 (MSH2) protein plays a central role in DNA MMR mechanism and is implicated in the cellular response to anticancer agents, such as cisplatin. Our aim was to clarify whether huCOP1 plays a role in DNA MMR by affecting MSH2 protein level in human keratinocytes. To define the role of huCOP1 in DNA mismatch repair, we determined whether huCOP1 affects MSH2 abundance. MSH2 protein level was detected by immunocytochemical staining using a keratinocyte cell line in which the expression level of huCOP1 was stably decreased (siCOP1). To investigate whether huCOP1 silencing influences cisplatin-induced cell death, control and siCOP1 keratinocyte cells were treated with increasing concentrations of cisplatin and cell viability was recorded after 48 and 96 h. Stable silencing of huCOP1 in human keratinocytes resulted in a reduced level of MSH2 protein. huCOP1 silencing also sensitized keratinocytes to the interstrand crosslinking inducer cisplatin. Our results indicate that decreased huCOP1 correlates with lower MSH2 levels. These protein level changes lead to increased sensitivity toward cisplatin treatment, implicating that huCOP1 plays a positive role in maintaining genome integrity in human keratinocytes.
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Wang KY, Chen CC, Tsai SF, Shen CKJ. Epigenetic Enhancement of the Post-replicative DNA Mismatch Repair of Mammalian Genomes by a Hemi- mCpG-Np95-Dnmt1 Axis. Sci Rep 2016; 6:37490. [PMID: 27886214 PMCID: PMC5122852 DOI: 10.1038/srep37490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 10/26/2016] [Indexed: 01/02/2023] Open
Abstract
DNA methylation at C of CpG dyads (mCpG) in vertebrate genomes is essential for gene regulation, genome stability and development. We show in this study that proper functioning of post-replicative DNA mismatch repair (MMR) in mammalian cells relies on the presence of genomic mCpG, as well as on the maintenance DNA methyltransferase Dnmt1 independently of its catalytic activity. More importantly, high efficiency of mammalian MMR surveillance is achieved through a hemi-mCpG-Np95(Uhrf1)-Dnmt1 axis, in which the MMR surveillance complex(es) is recruited to post-replicative DNA by Dnmt1, requiring its interactions with MutSα, as well as with Np95 bound at the hemi-methylated CpG sites. Thus, efficiency of MMR surveillance over the mammalian genome in vivo is enhanced at the epigenetic level. This synergy endows vertebrate CpG methylation with a new biological significance and, consequently, an additional mechanism for the maintenance of vertebrate genome stability.
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Affiliation(s)
- Keh-Yang Wang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Chun-Chang Chen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Shih-Feng Tsai
- Genome Research Center, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Che-Kun James Shen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
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91
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Santos JC, Brianti MT, Almeida VR, Ortega MM, Fischer W, Haas R, Matheu A, Ribeiro ML. Helicobacter pylori infection modulates the expression of miRNAs associated with DNA mismatch repair pathway. Mol Carcinog 2016; 56:1372-1379. [PMID: 27862371 DOI: 10.1002/mc.22590] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/27/2016] [Accepted: 11/11/2016] [Indexed: 02/06/2023]
Abstract
Genetic and epigenetic inactivation of DNA mismatch repair (MMR) genes might lead to modifications in cancer-related gene expression and cancer development. Recently, it has been shown that the infection by Helicobacter pylori, the major causative agent of gastric cancer, induces DNA damage and inhibits MMR DNA repair. Also, it has been reported that microRNAs (miRs) have an important role in regulating genomic stability and MMR DNA repair. Thus, the aim of this study was to identify miRs regulating MMR pathway in H. pylori-associated gastric carcinogenesis. To address this question, a gastric epithelial cell line and AGS cancer gastric cells were infected with several H. pylori strains. MMR gene expression and miRs correlating with H. pylori strain infection were evaluated. The results showed that H. pylori infection significantly down-regulated the expression of all selected MMR genes. Also, H. pylori infection modulated the expression of several miRs (including miR-150-5p, miR-155-5p, and miR-3163), after 4, 8, and 12 h of infection. Computational prediction of candidate miRs and their predicted MMR targeting sites were obtained from TargetScan, mirDB, and MetaCore. The generated data indicated that the selected miRs (miR-150-5p, miR-155-5p, and miR-3163) could possibly target and modulate MMR genes (POLD3, MSH2, and MSH3, respectively). The target validation was performed using mimics and luciferase gene reporter assays. Briefly, this study shows that H. pylori impairs MMR DNA repair pathway and identifies miRs that regulate MMR gene expression in gastric cancer. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Juliana C Santos
- Clinical Pharmacology and Gastroenterology Unit, São Francisco University Medical School, São Francisco University, Bragança Paulista, São Paulo, Brazil.,Women's Integrated Healthcare Center (CAISM), State University of Campinas, (UNICAMP) Campinas, São Paulo, Brazil
| | - Mitsue T Brianti
- Clinical Pharmacology and Gastroenterology Unit, São Francisco University Medical School, São Francisco University, Bragança Paulista, São Paulo, Brazil
| | - Victor R Almeida
- Clinical Pharmacology and Gastroenterology Unit, São Francisco University Medical School, São Francisco University, Bragança Paulista, São Paulo, Brazil
| | - Manoela M Ortega
- Clinical Pharmacology and Gastroenterology Unit, São Francisco University Medical School, São Francisco University, Bragança Paulista, São Paulo, Brazil
| | - Wolfgang Fischer
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, München, Germany
| | - Rainer Haas
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, München, Germany
| | - Ander Matheu
- Cellular Oncology Group, Biodonostia Health Research Institute, San Sebastian, and IKERBASQUE, Basque Foundation, Bilbao, Spain
| | - Marcelo L Ribeiro
- Clinical Pharmacology and Gastroenterology Unit, São Francisco University Medical School, São Francisco University, Bragança Paulista, São Paulo, Brazil
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92
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Yao DW, Zhan L, Hong YF, Liu JX, Xu JR, Yang DJ. Altered expression of the mismatch repair genes in DF-1 cells infected with the avian leukosis virus subgroup A. SPRINGERPLUS 2016; 5:1756. [PMID: 27795899 PMCID: PMC5055512 DOI: 10.1186/s40064-016-3433-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/29/2016] [Indexed: 11/17/2022]
Abstract
The absence or deficiency of DNA mismatch repair (MMR) activity results in microsatellite instability (MSI) in cancer. The avian leukosis virus (ALV) causes neoplastic disease in chickens. In this study, the status of MMR, MSI, the cell cycle and apoptosis were detected in DF-1 cells after avian leukosis virus subgroup A infection. Flow cytometry analysis results indicated that there was no significant difference in cell apoptosis between the control and infected groups. The percentage of cells in S and G2 phases were increased in the infected group. MSI and mutation of MSH2 and MLH1 gene exons were absent in DF-1 cells after infection. Levels of MSH2 and MLH1 mRNA were dramatically increased in DF-1 cells after infection. These results demonstrated that ALV RAV-1 infection may promote the expression of MSH2 and MLH1 genes rather than resulting in gene mutations. Mismatch repair functions were normal and may be have relationships with the arrest of S phase and G2 phase.
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Affiliation(s)
- Da-Wei Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Li Zhan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Yu-Fang Hong
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Jian-Xin Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Jia-Rong Xu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - De-Ji Yang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
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93
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Hu MH, Liu SY, Wang N, Wu Y, Jin F. Impact of DNA mismatch repair system alterations on human fertility and related treatments. J Zhejiang Univ Sci B 2016; 17:10-20. [PMID: 26739522 DOI: 10.1631/jzus.b1500162] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA mismatch repair (MMR) is one of the biological pathways, which plays a critical role in DNA homeostasis, primarily by repairing base-pair mismatches and insertion/deletion loops that occur during DNA replication. MMR also takes part in other metabolic pathways and regulates cell cycle arrest. Defects in MMR are associated with genomic instability, predisposition to certain types of cancers and resistance to certain therapeutic drugs. Moreover, genetic and epigenetic alterations in the MMR system demonstrate a significant relationship with human fertility and related treatments, which helps us to understand the etiology and susceptibility of human infertility. Alterations in the MMR system may also influence the health of offspring conceived by assisted reproductive technology in humans. However, further studies are needed to explore the specific mechanisms by which the MMR system may affect human infertility. This review addresses the physiological mechanisms of the MMR system and associations between alterations of the MMR system and human fertility and related treatments, and potential effects on the next generation.
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Affiliation(s)
- Min-hao Hu
- Key Laboratory of Reproductive Genetics (Zhejiang), Ministry of Education, and Centre of Reproductive Medicine, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | - Shu-yuan Liu
- Key Laboratory of Reproductive Genetics (Zhejiang), Ministry of Education, and Centre of Reproductive Medicine, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | - Ning Wang
- Key Laboratory of Reproductive Genetics (Zhejiang), Ministry of Education, and Centre of Reproductive Medicine, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | - Yan Wu
- Key Laboratory of Reproductive Genetics (Zhejiang), Ministry of Education, and Centre of Reproductive Medicine, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | - Fan Jin
- Key Laboratory of Reproductive Genetics (Zhejiang), Ministry of Education, and Centre of Reproductive Medicine, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
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94
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Chakraborty U, Alani E. Understanding how mismatch repair proteins participate in the repair/anti-recombination decision. FEMS Yeast Res 2016; 16:fow071. [PMID: 27573382 PMCID: PMC5976031 DOI: 10.1093/femsyr/fow071] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/24/2016] [Accepted: 08/24/2016] [Indexed: 01/06/2023] Open
Abstract
Mismatch repair (MMR) systems correct DNA mismatches that result from DNA polymerase misincorporation errors. Mismatches also appear in heteroduplex DNA intermediates formed during recombination between nearly identical sequences, and can be corrected by MMR or removed through an unwinding mechanism, known as anti-recombination or heteroduplex rejection. We review studies, primarily in baker's yeast, which support how specific factors can regulate the MMR/anti-recombination decision. Based on recent advances, we present models for how DNA structure, relative amounts of key repair proteins, the timely localization of repair proteins to DNA substrates and epigenetic marks can modulate this critical decision.
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Affiliation(s)
- Ujani Chakraborty
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA
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95
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Lai Y, Budworth H, Beaver JM, Chan NLS, Zhang Z, McMurray CT, Liu Y. Crosstalk between MSH2-MSH3 and polβ promotes trinucleotide repeat expansion during base excision repair. Nat Commun 2016; 7:12465. [PMID: 27546332 PMCID: PMC4996945 DOI: 10.1038/ncomms12465] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/06/2016] [Indexed: 01/07/2023] Open
Abstract
Studies in knockout mice provide evidence that MSH2-MSH3 and the BER machinery promote trinucleotide repeat (TNR) expansion, yet how these two different repair pathways cause the mutation is unknown. Here we report the first molecular crosstalk mechanism, in which MSH2-MSH3 is used as a component of the BER machinery to cause expansion. On its own, pol β fails to copy TNRs during DNA synthesis, and bypasses them on the template strand to cause deletion. Remarkably, MSH2-MSH3 not only stimulates pol β to copy through the repeats but also enhances formation of the flap precursor for expansion. Our results provide direct evidence that MMR and BER, operating together, form a novel hybrid pathway that changes the outcome of TNR instability from deletion to expansion during the removal of oxidized bases. We propose that cells implement crosstalk strategies and share machinery when a canonical pathway is ineffective in removing a difficult lesion.
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Affiliation(s)
- Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
| | - Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Jill M. Beaver
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
| | - Nelson L. S. Chan
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Zunzhen Zhang
- Department of Occupational and Environmental Health, Sichuan University West China School of Public Health, 16#, Section 3, Renmin Nan Lu, Chengdu, Sichuan 610041, China
| | - Cynthia T. McMurray
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
- Biomolecular Sciences Institute, School of Integrated Sciences and Humanity, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
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96
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Amaral-Silva GKD, Martins MD, Pontes HAR, Fregnani ER, Lopes MA, Fonseca FP, Vargas PA. Mismatch repair system proteins in oral benign and malignant lesions. J Oral Pathol Med 2016; 46:241-245. [PMID: 27509575 DOI: 10.1111/jop.12484] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2016] [Indexed: 12/15/2022]
Abstract
Different environmental agents may cause DNA mutations by disrupting its double-strand structure; however, even normal DNA polymerase function may synthesize mismatch nucleotide bases, occasionally demonstrating failure in its proofreading activity. To overcome this issue, mismatch repair (MMR) system, a group of proteins specialized in finding mispairing bases and small loops of insertion or deletion, works to avoid the occurrence of mutations that could ultimately lead to innumerous human diseases. In the last decades, the role of MMR proteins in oral carcinogenesis and in the development of other oral cavity neoplasms has grown, but their importance in the pathogenesis and their prognostic potential for patients affected by oral malignancies, especially oral squamous cell carcinoma (OSCC), remain unclear. Therefore, in this manuscript we aimed to review and critically discuss the currently available data on MMR proteins expression in oral potentially malignant lesions, in OSCC, and in other oral neoplasms to better understand their relevance in these lesions.
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Affiliation(s)
| | - Manoela Domingues Martins
- Department of Pathology, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Hélder Antônio Rebelo Pontes
- Service of Buccal Pathology, João de Barros Barreto University Hospital, Federal University of Pará, Belém, Brazil
| | | | - Márcio Ajudarte Lopes
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Felipe Paiva Fonseca
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Pablo Agustin Vargas
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
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97
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Session 10: Dna Repair. Toxicol Pathol 2016. [DOI: 10.1080/01926230490882501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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98
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Gu Y, Helenius M, Väänänen K, Bulanova D, Saarela J, Sokolenko A, Martens J, Imyanitov E, Kuznetsov S. BRCA1-deficient breast cancer cell lines are resistant to MEK inhibitors and show distinct sensitivities to 6-thioguanine. Sci Rep 2016; 6:28217. [PMID: 27313062 PMCID: PMC4911578 DOI: 10.1038/srep28217] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 06/01/2016] [Indexed: 12/27/2022] Open
Abstract
Germ-line or somatic inactivation of BRCA1 is a defining feature for a portion of human breast cancers. Here we evaluated the anti-proliferative activity of 198 FDA-approved and experimental drugs against four BRCA1-mutant (HCC1937, MDA-MB-436, SUM1315MO2, and SUM149PT) and four BRCA1-wild-type (MDA-MB-231, SUM229PE, MCF10A, and MCF7) breast cancer cell lines. We found that all BRCA1-mutant cell lines were insensitive to inhibitors of mitogen-activated protein kinase kinase 1 and 2 (MEK1/2) Selumetinib and Pimasertib in contrast to BRCA1-wildtype control cell lines. However, unexpectedly, only two BRCA1-mutant cell lines, HCC1937 and MDA-MB-436, were hypersensitive to a nucleotide analogue 6-thioguanine (6-TG). SUM149PT cells readily formed radiation-induced RAD51-positive nuclear foci indicating a functional homologous recombination, which may explain their resistance to 6-TG. However, the reason underlying 6-TG resistance of SUM1315MO2 cells remains unclear. Our data reveal a remarkable heterogeneity among BRCA1-mutant cell lines and provide a reference for future studies.
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Affiliation(s)
- Yuexi Gu
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland
| | - Mikko Helenius
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland
| | - Kristiina Väänänen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland.,Department of Biology, University of Eastern Finland, PO Box 111, FI-80101 Joensuu, Finland
| | - Daria Bulanova
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland
| | - Jani Saarela
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland
| | - Anna Sokolenko
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, St.-Petersburg 197758, Russia.,Department of Medical Genetics, St.-Petersburg Pediatric Medical University, St.-Petersburg 194100, Russia
| | - John Martens
- Erasmus University Medical Center, Daniel den Hoed Cancer Center, Department of Medical Oncology and Cancer Genomics Center, Dr. Molewaterplein 50, 3015 GE Rotterdam, the Netherlands
| | - Evgeny Imyanitov
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, St.-Petersburg 197758, Russia.,Department of Medical Genetics, St.-Petersburg Pediatric Medical University, St.-Petersburg 194100, Russia.,Department of Oncology, I.I. Mechnikov North-Western Medical University, St.-Petersburg 191015, Russia
| | - Sergey Kuznetsov
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, PO Box 20, FIN-00014, Helsinki, Finland
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99
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Lan J, Gou N, Rahman SM, Gao C, He M, Gu AZ. A Quantitative Toxicogenomics Assay for High-throughput and Mechanistic Genotoxicity Assessment and Screening of Environmental Pollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:3202-14. [PMID: 26855253 PMCID: PMC6321748 DOI: 10.1021/acs.est.5b05097] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ecological and health concern of mutagenicity and carcinogenicity potentially associated with an overwhelmingly large and ever-increasing number of chemicals demands for cost-effective and feasible method for genotoxicity screening and risk assessment. This study proposed a genotoxicity assay using GFP-tagged yeast reporter strains, covering 38 selected protein biomarkers indicative of all the seven known DNA damage repair pathways. The assay was applied to assess four model genotoxic chemicals, eight environmental pollutants and four negative controls across six concentrations. Quantitative molecular genotoxicity end points were derived based on dose response modeling of a newly developed integrated molecular effect quantifier, Protein Effect Level Index (PELI). The molecular genotoxicity end points were consistent with multiple conventional in vitro genotoxicity assays, as well as with in vivo carcinogenicity assay results. Further more, the proposed genotoxicity end point PELI values quantitatively correlated with both comet assay in human cell and carcinogenicity potency assay in mice, providing promising evidence for linking the molecular disturbance measurements to adverse outcomes at a biological relevant level. In addition, the high-resolution DNA damaging repair pathway alternated protein expression profiles allowed for chemical clustering and classification. This toxicogenomics-based assay presents a promising alternative for fast, efficient and mechanistic genotoxicity screening and assessment of drugs, foods, and environmental contaminants.
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Affiliation(s)
- Jiaqi Lan
- Department of Civil and Environmental Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Na Gou
- Department of Civil and Environmental Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Sheikh Mokhles Rahman
- Department of Civil and Environmental Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ce Gao
- Department of Civil and Environmental Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Miao He
- Environmental Simulation and Pollution Control (ESPC) State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China
- (Miao He) .
| | - April Z. Gu
- Department of Civil and Environmental Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
- Corresponding Authors (April Z. Gu)
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100
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Schmidt TT, Hombauer H. Visualization of mismatch repair complexes using fluorescence microscopy. DNA Repair (Amst) 2016; 38:58-67. [DOI: 10.1016/j.dnarep.2015.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/30/2015] [Accepted: 11/30/2015] [Indexed: 11/15/2022]
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