DOCSLIB.ORG

Functional Analysis of Human MLH1 Variants Using Yeast and in Vitro Mismatch Repair Assays

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Functional Analysis of Human MLH1 Variants Using Yeast and in Vitro Mismatch Repair Assays Research Article Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays Masanobu Takahashi,1 Hideki Shimodaira,1 Corinne Andreutti-Zaugg,2 Richard Iggo,2 Richard D. Kolodner,3 and Chikashi Ishioka1 1Department of Clinical Oncology, Institute of Development, Aging and Cancer, and Tohoku University Hospital, Tohoku University, Sendai, Japan; 2Oncogene Group, Swiss Institute for Experimental Cancer Research, Epalinges, Switzerland; and 3Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, California Abstract In the two MMR genes, MLH1 and MSH2, which account for the The functional characterization of nonsynonymous single majority of HNPCC kindred mutations, 31.6% of the MLH1 nucleotide polymorphisms in human mismatch repair mutations and 19.4% of the MSH2 mutations are missense (nonsynonymous single nucleotide polymorphisms) according to (MMR) genes has been critical to evaluate their pathogenicity 4 for hereditary nonpolyposis colorectal cancer. We previously the InSiGHT database. Pathogenic significances of nonsynon- established an assay for detecting loss-of-function mutations ymous single nucleotide polymorphisms are not easily evaluated in the MLH1 gene using a dominant mutator effect of human without a functional assay. Generally, this makes genetic diagnosis MLH1 expressed in Saccharomyces cerevisiae. The purpose of more difficult, especially when phenotype-genotype segregation this study is to extend the functional analyses of nonsynon- analysis is limited because of an ethical issue, the small number of family members, or other reasons. Therefore, functional analysis ymous single nucleotide polymorphisms in the MLH1 gene both in quality and in quantity, and integrate the results to has been needed to interpret the pathogenicity of MLH1 variants evaluate the variants for pathogenic significance. The 101 in genetic diagnoses of HNPCC. MLH1 variants, which covered most of the reported MLH1 Several groups, including ours, have attempted to resolve this nonsynonymous single nucleotide polymorphisms and con- issue by analyzing the functional significance of MLH1 variants by sisted of one 3-bp deletion, 1 nonsense and 99 missense various methods (1–8). We found a dominant mutator effect (DME) variants, were examined for the dominant mutator effect by of wild-type MLH1 on interference in the yeast MMR system and three yeast assays and for the ability of the variant to repair a evaluated the pathogenicity of 20 MLH1 missense variants using heteroduplex DNA with mismatch bases by in vitro MMR this effect for a yeast-based functional assay (1). One of the other assay. There was diversity in the dominant mutator effects strategies was focusing on the well-defined functions of MLH1, and the in vitro MMR activities among the variants. The ATPase activity in the NH2 terminus, and the binding abilities with majority of functionally inactive variants were located around PMS2 in the COOH terminus (2, 4, 7). Another strategy was based the putative ATP-binding pocket of the NH -terminal domain on the assessment of total MMR activity such as in vitro MMR 2 assay, monitoring the MMR rate of cell extracts for heteroduplex or the whole region of the COOH-terminal domain. Integrated functional evaluations contribute to a better prediction of DNA-containing mismatch bases (4, 5), or yeast system measuring the cancer risk in individuals or families carrying MLH1 the replication error rate resulting from the expressed yeast-human variants and provide insights into the function-structure hybrid proteins or equivalent yeast variants (3). An alternative relationships in MLH1. [Cancer Res 2007;67(10):4595–604] approach was to analyze the effects of an MLH1 variant for the expression of MLH1 mRNA and protein and the proliferation rate of cells when an MLH1 variant was introduced into the cells (6). Introduction Recently, MLH1 variants were characterized for the multiple Hereditary nonpolyposis colorectal cancer (HNPCC) is one of functional properties of wild-type MLH1, including protein the most common familial cancer syndromes caused by mainly expression, subcellular localization, MLH1-PMS2 interaction, and germ-line mutations in DNA mismatch repair (MMR) genes, such MMR efficiency (8). However, it still seems to be important to as MLH1, MSH2, MSH6, and PMS2. MMR contributes to genome establish the database on the functional effects of as many variants integrity by correcting replication errors, particularly mismatch as possible by various methods and integrate the accumulated data base pairs or slippages in simple repeat sequences. The MMR for better understanding of MLH1 variants. system is well conserved from Escherichia coli to mammals, and Beyond functional analyses, crystal structure analyses of E. coli the E. coli MMR system, where MutS, MutL, and MutH complexes MutL were used to predict the structural alterations of MLH1 function, has been well analyzed. In mammalian cells, hetero- variants (9, 10). Besides the NH2 terminus, the crystal structure of the dimers of MutS homologues (MSH2-MSH6 and MSH2-MSH3) COOH terminus of E. coli MutL was identified recently (11). recognize replication errors, and the heterodimer of the MutL Consideration of the protein structure permits more comprehensive homologue (MLH1-PMS2) interacts with MutS homologues and analysis of MLH1 and is thought to provide useful information for recruits further repair proteins. interpreting the pathogenesis of MLH1 variants in genetic diagnoses. In this study, we examined 101 MLH1 variants in yeast assays and an in vitro MMR assay, to compare these two assays and to Requests for reprints: Chikashi Ishioka, Department of Clinical Oncology, Institute of Development, Aging and Cancer, and Tohoku University Hospital, develop the functional database for a large number of variations. Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan. Phone: 81-22- 717-8547; Fax: 81-22-717-8548; E-mail: [email protected]. I2007 American Association for Cancer Research. doi:10.1158/0008-5472.CAN-06-3509 4 http://www.insight-group.org/ www.aacrjournals.org 4595 Cancer Res 2007; 67: (10). May 15, 2007 Downloaded from cancerres.aacrjournals.org on September 30, 2021. © 2007 American Association for Cancer Research. Cancer Research Table 1. Summary of MLH1 variants Variant Nucleotide Dominant mutator effect In vitro MMR Relative MLH1 SIFT AC+/All Reference change activity (%) expression (%) score families* LacZ GFP ADE2 Missense c E23D 69A>T + + + 25.2 >75 0.00 NI I c b I25F 73A>T + + + 36.4 >75 0.00 NI I c I25T 74T>C + + + 67.2 25–75 0.00 1/1 I P28L 83C>T ÀÀ + 9.2 >75 0.00 1/3 I, S, 8 A29S 85G>T + + + 81.7 >75 0.26 1/1 I, 8 M35R 104T>G ÀÀ À 23.4 25–75 0.00 1/1 I, S c N38D 112A>G À + + 0.0 25–75 0.00 0/1 15 c S44A 130T>G + + + 65.9 >75 1.00 P 16 S44F 131C>T ÀÀ À 23.1 <25 0.00 1/2 I, S c G54E 161G>A ÀÀ + 47.9 >75 0.00 So S c N64S 191A>G ÀÀ + 36.6 >75 0.02 1/1 I, S G67R 199G>A ÀÀ À 5.9 <25 0.00 2/4 I, S, 16, 17 c G67W 199G>T ÀÀ À 7.3 25–75 0.00 1/1 S c I68V 202A>G + + + 79.8 >75 0.02 P 16 I68N 203T>A ÀÀ À 20.8 25–75 0.00 1/1 I. S R69K 206G>A + + + 75.0 >75 0.91 0/1 S C77Y 230G>A À + + 11.2 25–75 0.15 0/1 I, S F80V 238T>G ÀÀ + 23.7 >75 0.07 1/1 S, 8 c T82I 245C>T À + + 27.2 >75 0.00 1/1 18 K84E 250A>G À + + 22.5 >75 0.00 0/1 I, S S93G 277A>G + + + 80.3 >75 0.16 1/2 I, S, 8 c R100P 299G>C À + + 0.0 <25 0.00 NI I E102K 304G>A + + + 44.4 >75 0.00 1/1 I c E102D 306G>T + + + 56.1 >75 0.00 NI I I107R 320T>G ÀÀ À 39.5 25–75 0.00 5/7 I, S, 8, 19 c A111V 332C>T ÀÀ À 25.5 25–75 0.01 2/2 S, 20 T117M 350C>T ÀÀ À 34.8 <25 0.00 12/14 I, S, 15, 21, 22 T117R 350C>G ÀÀ À 25.2 25–75 0.00 1/1 I, S A128P 382G>C ÀÀ À 24.4 25–75 0.01 1/1 I, S D132H 394G>C + + + 63.0 25–75 0.02 0/1 S, 23 c A160V 479C>T + + + 80.9 >75 0.01 NI I c R182G 544A>G + + + 74.3 25–75 0.00 0/1 I, S V185G 554T>G ÀÀ À 8.5 25–75 0.00 2/3 I, S, 8, 15 c S193P 577T>C ÀÀ À 0.0 >75 0.10 1/1 I, S, 24 c E199Q 595G>C + + + 67.7 >75 0.15 0/1 I V213M 637G>A + + + 85.0 >75 0.11 P I, S R217C 649C>T + À + 64.8 >75 0.11 1/2 I, S I219L 655A>C + + + 85.2 >75 0.52 P I I219V 655A>G + + + 60.7 25–75 0.46 P I, S c R226L 677G>T ÀÀ + 39.2 25–75 0.04 2/2 I, S G244D 731G>A ÀÀ À 19.4 >75 0.00 1/1 I, S c G244V 731G>T ÀÀ À 18.8 >75 0.00 So S, 25 c H264R 791A>G + + + 68.7 >75 0.07 1/1 I R265C 793C>T À + + 55.0 25–75 0.00 3/4 I b R265H 794G>A + + + 61.1 >75 0.00 NI I, S c b E268G 803A>G + À + 78.9 25–75 0.05 NI I, S c L272V 814T>G + + + 90.2 >75 0.10 NI I c A281V 842C>T + + + 88.6 25–75 0.27 NI I c K286Q 856A>C + À + 78.6 25–75 0.39 1/1 26 c S295G 883A>G À + + 75.5 25–75 0.46 1/1 I, S c D304V 911A>T ÀÀ + 0.0 >75 0.00 1/1 27 V326A 977T>C + + + 26.9 25–75 0.00 3/5 I, S, 21, 28 H329P 986A>C ÀÀ + 25.7 >75 0.21 2/2 I, S, 8 c V384D 1151T>A + + + 64.8 >75 0.07 P I, S c R389Q 1166G>A + + + 83.6 >75 0.31 NI I (Continued on the following page) Cancer Res 2007; 67: (10).
Load more

Recommended publications
  • A Dissertation Entitled the Role of Base Excision Repair And
    A Dissertation Entitled The Role of Base Excision Repair and Mismatch Repair Proteins in the Processing of Cisplatin Interstrand Cross-Links. by Akshada Sawant Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Biomedical Science Dr. Stephan M. Patrick, Committee Chair Dr. Kandace Williams, Committee Member Dr. William Maltese, Committee Member Dr. Manohar Ratnam, Committee Member Dr. David Giovannucci, Committee Member Dr. Patricia R. Komuniecki, Dean College of Graduate Studies The University of Toledo August 2014 Copyright 2014, Akshada Sawant This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of The Role of Base Excision Repair and Mismatch Repair Proteins in the Processing of Cisplatin Interstrand Cross-Links By Akshada Sawant Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Biomedical Science The University of Toledo August 2014 Cisplatin is a well-known anticancer agent that forms a part of many combination chemotherapeutic treatments used against a variety of human cancers. Despite successful treatment, the development of resistance is the major limitation of the cisplatin based therapy. Base excision repair modulates cisplatin cytotoxicity. Moreover, mismatch repair deficiency gives rise to cisplatin resistance and leads to poor prognosis of the disease. Various models have been proposed to explain this low level of resistance caused due to loss of MMR proteins. In our previous studies, we have shown that BER processing of the cisplatin ICLs is mutagenic. Our studies showed that these mismatches lead to the activation and the recruitment of mismatch repair proteins.
    [Show full text]
  • Complex Interacts with WRN and Is Crucial to Regulate Its Response to Replication Fork Stalling
    Oncogene (2012) 31, 2809–2823 & 2012 Macmillan Publishers Limited All rights reserved 0950-9232/12 www.nature.com/onc ORIGINAL ARTICLE The RAD9–RAD1–HUS1 (9.1.1) complex interacts with WRN and is crucial to regulate its response to replication fork stalling P Pichierri, S Nicolai, L Cignolo1, M Bignami and A Franchitto Department of Environment and Primary Prevention, Istituto Superiore di Sanita`, Rome, Italy The WRN protein belongs to the RecQ family of DNA preference toward substrates that mimic structures helicases and is implicated in replication fork restart, but associated with stalled replication forks (Brosh et al., how its function is regulated remains unknown. We show 2002; Machwe et al., 2006) and WS cells exhibit that WRN interacts with the 9.1.1 complex, one of enhanced instability at common fragile sites, chromo- the central factors of the replication checkpoint. This somal regions especially prone to replication fork interaction is mediated by the binding of the RAD1 stalling (Pirzio et al., 2008). How WRN favors recovery subunit to the N-terminal region of WRN and is of stalled forks and prevents DNA breakage upon instrumental for WRN relocalization in nuclear foci and replication perturbation is not fully understood. It has its phosphorylation in response to replication arrest. We been suggested that WRN might facilitate replication also find that ATR-dependent WRN phosphorylation restart by either promoting recombination or processing depends on TopBP1, which is recruited by the 9.1.1 intermediates at stalled forks in a way that counteracts complex in response to replication arrest. Finally, we unscheduled recombination (Franchitto and Pichierri, provide evidence for a cooperation between WRN and 2004; Pichierri, 2007; Sidorova, 2008).
    [Show full text]
  • Genome Instability in Secondary Solid Tumors Developing After Radiotherapy of Bilateral Retinoblastoma
    Oncogene (2001) 20, 8092 ± 8099 ã 2001 Nature Publishing Group All rights reserved 0950 ± 9232/01 $15.00 www.nature.com/onc Genome instability in secondary solid tumors developing after radiotherapy of bilateral retinoblastoma Sandrine-He leÁ ne LefeÁ vre1, Nicolas Vogt1, Anne-Marie Dutrillaux1, Laurent Chauveinc2, Dominique Stoppa-Lyonnet3, FrancËois Doz4, Laurence Desjardins5, Bernard Dutrillaux1,6, Sylvie Chevillard6 and Bernard Malfoy*,1 1Institut Curie ± CNRS UMR 147, 26 rue d'Ulm 75248 Paris Cedex 05, France; 2Institut Curie, Service de RadiotheÂrapie, 26 rue d'Ulm 75248 Paris Cedex 05, France; 3Institut Curie, Service de GeÂneÂtique Oncologique, 26 rue d'Ulm 75248 Paris Cedex 05, France; 4Institut Curie, Service de PeÂdiatrie, 26 rue d'Ulm 75248 Paris Cedex 05, France; 5Institut Curie, Service d'Ophtalmologie, 26 rue d'Ulm 75248 Paris Cedex 05, France; 6CEA, DSV DRR, 60 avenue du GeÂneÂral Leclerc 92265 Fontenay-aux-Roses, France Genome alterations of seven secondary tumors (®ve these cancers and the diculty in collecting a series of osteosarcomas, one malignant peripheral sheath nerve cases in clearly de®ned context. tumor, one leiomyosarcoma) occurring in the ®eld of It is well established that therapeutic irradiation can irradiation of patients treated for bilateral retinoblasto- induce secondary malignancies within or at the margin ma have been studied. These patients were predisposed to of the radiation ®eld after a long latent period. These develop radiation-induced tumors because of the presence tumors have dierent histology from the primary of a germ line mutation in the retinoblastoma gene lesions, with sarcomas being common (Robinson et (RB1). Tumor cells were characterized by a high al., 1988).
    [Show full text]
  • Genomic Instability Promoted by Overexpression of Mismatch Repair Factors in Yeast: a Model for Understanding Cancer Progression
    HIGHLIGHTED ARTICLE | INVESTIGATION Genomic Instability Promoted by Overexpression of Mismatch Repair Factors in Yeast: A Model for Understanding Cancer Progression Ujani Chakraborty,* Timothy A. Dinh,† and Eric Alani*,1 *Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703 and †Curriculum in Genetics and Molecular Biology, Biological and Biomedical Sciences Program, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599 ORCID ID: 0000-0002-5011-9339 (E.A.) ABSTRACT Mismatch repair (MMR) proteins act in spellchecker roles to excise misincorporation errors that occur during DNA replication. Curiously, large-scale analyses of a variety of cancers showed that increased expression of MMR proteins often correlated with tumor aggressiveness, metastasis, and early recurrence. To better understand these observations, we used The Cancer Genome Atlas and Gene Expression across Normal and Tumor tissue databases to analyze MMR protein expression in cancers. We found that the MMR genes MSH2 and MSH6 are overexpressed more frequently than MSH3, and that MSH2 and MSH6 are often cooverex- pressed as a result of copy number amplifications of these genes. These observations encouraged us to test the effects of upregulating MMR protein levels in baker’s yeast, where we can sensitively monitor genome instability phenotypes associated with cancer initiation and progression. Msh6 overexpression (two- to fourfold) almost completely disrupted mechanisms that prevent recombination be- tween divergent DNA sequences by interacting with the DNA polymerase processivity clamp PCNA and by sequestering the Sgs1 helicase. Importantly, cooverexpression of Msh2 and Msh6 (eightfold) conferred, in a PCNA interaction-dependent manner, several genome instability phenotypes including increased mutation rate, increased sensitivity to the DNA replication inhibitor HU and the DNA-damaging agents MMS and 4-nitroquinoline N-oxide, and elevated loss-of-heterozygosity.
    [Show full text]
  • Epigenetic Regulation of DNA Repair Genes and Implications for Tumor Therapy ⁎ ⁎ Markus Christmann , Bernd Kaina
    Mutation Research-Reviews in Mutation Research xxx (xxxx) xxx–xxx Contents lists available at ScienceDirect Mutation Research-Reviews in Mutation Research journal homepage: www.elsevier.com/locate/mutrev Review Epigenetic regulation of DNA repair genes and implications for tumor therapy ⁎ ⁎ Markus Christmann , Bernd Kaina Department of Toxicology, University of Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany ARTICLE INFO ABSTRACT Keywords: DNA repair represents the first barrier against genotoxic stress causing metabolic changes, inflammation and DNA repair cancer. Besides its role in preventing cancer, DNA repair needs also to be considered during cancer treatment Genotoxic stress with radiation and DNA damaging drugs as it impacts therapy outcome. The DNA repair capacity is mainly Epigenetic silencing governed by the expression level of repair genes. Alterations in the expression of repair genes can occur due to tumor formation mutations in their coding or promoter region, changes in the expression of transcription factors activating or Cancer therapy repressing these genes, and/or epigenetic factors changing histone modifications and CpG promoter methylation MGMT Promoter methylation or demethylation levels. In this review we provide an overview on the epigenetic regulation of DNA repair genes. GADD45 We summarize the mechanisms underlying CpG methylation and demethylation, with de novo methyl- TET transferases and DNA repair involved in gain and loss of CpG methylation, respectively. We discuss the role of p53 components of the DNA damage response, p53, PARP-1 and GADD45a on the regulation of the DNA (cytosine-5)- methyltransferase DNMT1, the key enzyme responsible for gene silencing. We stress the relevance of epigenetic silencing of DNA repair genes for tumor formation and tumor therapy.
    [Show full text]
  • The Diagnostic Value of DNA Repair Gene in Breast Cancer Recurrence and Metastasis
    The Diagnostic Value of DNA Repair Gene in Breast Cancer Recurrence and Metastasis Yongxin Yang Southwest Medical University Xiabin Li Southwest Medical University Liyue Hao Southwest Medical University Deyong Jiang Centers for Disease Control and Prevention Bin Wu Southwest Medical University Tao He Southwest Medical University Yan Tang ( [email protected] ) Research Keywords: PARP1, XRCC4, ERCC1, Breast cancer Posted Date: June 25th, 2020 DOI: https://doi.org/10.21203/rs.3.rs-36932/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/19 Abstract Background: DNA repair genes play a vital role in the treatment of many cancers, and DNA repair genes can be used in breast cancer recurrence and metastasis research. We found that the expression of DNA repair genes in breast cancer patients after recurrence and metastasis is abnormal, however, the clinical predictive signicance of DNA repair genes is still elusive. Methods: The nested case-control method was used in patients with breast cancer recurrence and metastasis after surgery (n=109) and patients without recurrence and metastasis after surgery (n=109). The proteins and mRNA of DNA repair genes were detected by immunohistochemistry and Real-time PCR respectively. Results: PARP1(OR=1.485, 95%CI:1.279~1.725, P<0.05), XRCC4(OR= 1.419, 95%CI:1.217~ 1.656, P<0.05) and ERCC1 (OR=1.181, 95%CI: 1.032~1.353, P<0.05) were risk factors for postoperative recurrence and metastasis of breast cancer. Therefore, we used the ROC
    [Show full text]
  • WRN Promoter Methylation Possibly Connects Mucinous Differentiation, Microsatellite Instability and Cpg Island Methylator Phenotype in Colorectal Cancer
    Modern Pathology (2008) 21, 150–158 & 2008 USCAP, Inc All rights reserved 0893-3952/08 $30.00 www.modernpathology.org WRN promoter methylation possibly connects mucinous differentiation, microsatellite instability and CpG island methylator phenotype in colorectal cancer Takako Kawasaki1,2, Mutsuko Ohnishi2, Yuko Suemoto2, Gregory J Kirkner3, Zhiqian Liu2, Hiroyuki Yamamoto4, Massimo Loda1,2, Charles S Fuchs2,3 and Shuji Ogino1,2 1Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA; 2Department of Medical Oncology, Dana–Farber Cancer Institute, Boston, MA, USA; 3Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA and 4First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan Werner syndrome is a premature aging syndrome characterized by early onset of cancer and abnormal cellular metabolism of glycosaminoglycan. The WRN helicase plays an important role in the maintenance of telomere function. WRN promoter methylation and gene silencing are common in colorectal cancer with the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and mucinous tumors. However, no study has examined the relationship between mucinous differentiation, WRN methylation, CIMP and MSI in colorectal cancer. Utilizing 903 population-based colorectal cancers and real-time PCR (MethyLight), we quantified DNA methylation in WRN and eight other promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) known to be specific for CIMP. Supporting WRN as a good CIMP marker, WRN methylation was correlated well with CIMP-high diagnosis (Z6/8 methylated promoters), demonstrating 89% sensitivity and 81% specificity. WRN methylation was associated with the presence of any mucinous component and Z50% mucinous component (Po0.0001).
    [Show full text]
  • Origin of Genome Instability and Determinants of Mutational Landscape in Cancer Cells
    G C A T T A C G G C A T genes Review Origin of Genome Instability and Determinants of Mutational Landscape in Cancer Cells Sonam Mehrotra * and Indraneel Mittra Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, India; [email protected] * Correspondence: [email protected]; Tel.: +91-22-27405143 Received: 15 August 2020; Accepted: 18 September 2020; Published: 21 September 2020 Abstract: Genome instability is a crucial and early event associated with an increased predisposition to tumor formation. In the absence of any exogenous agent, a single human cell is subjected to about 70,000 DNA lesions each day. It has now been shown that physiological cellular processes including DNA transactions during DNA replication and transcription contribute to DNA damage and induce DNA damage responses in the cell. These processes are also influenced by the three dimensional-chromatin architecture and epigenetic regulation which are altered during the malignant transformation of cells. In this review, we have discussed recent insights about how replication stress, oncogene activation, chromatin dynamics, and the illegitimate recombination of cell-free chromatin particles deregulate cellular processes in cancer cells and contribute to their evolution. The characterization of such endogenous sources of genome instability in cancer cells can be exploited for the development of new biomarkers and more effective therapies for cancer treatment. Keywords: genome instability; replication stress; replication-transcription conflict; cell free chromatin; cancer 1. Introduction Genome instability is a characteristic feature observed in most human cancers. The accumulation of genetic alterations ranging from single nucleotide mutations to chromosome rearrangements can predispose cells towards malignancy.
    [Show full text]
  • Predisposition to Hematologic Malignancies in Patients With
    LETTERS TO THE EDITOR carcinomas but no internal cancer by the age of 29 years Predisposition to hematologic malignancies in and 9 years, respectively. patients with xeroderma pigmentosum Case XP540BE . This patient had a highly unusual pres - entation of MPAL. She was diagnosed with XP at the age Germline predisposition is a contributing etiology of of 18 months with numerous lentigines on sun-exposed hematologic malignancies, especially in children and skin, when her family emigrated from Morocco to the young adults. Germline predisposition in myeloid neo - USA. The homozygous North African XPC founder muta - plasms was added to the World Health Organization tion was present. 10 She had her first skin cancer at the age 1 2016 classification, and current management recommen - of 8 years, and subsequently developed more than 40 cuta - dations emphasize the importance of screening appropri - neous basal and squamous cell carcinomas, one melanoma 2 ate patients. Rare syndromes of DNA repair defects can in situ , and one ocular surface squamous neoplasm. She 3 lead to myeloid and/or lymphoid neoplasms. Here, we was diagnosed with a multinodular goiter at the age of 9 describe our experience with hematologic neoplasms in years eight months, with several complex nodules leading the defective DNA repair syndrome, xeroderma pigmen - to removal of her thyroid gland. Histopathology showed tosum (XP), including myelodysplastic syndrome (MDS), multinodular adenomatous/papillary hyperplasia. At the secondary acute myeloid leukemia (AML), high-grade age of 19 years, she presented with night sweats, fatigue, lymphoma, and an extremely unusual presentation of and lymphadenopathy. Laboratory studies revealed pancy - mixed phenotype acute leukemia (MPAL) with B, T and topenia with hemoglobin 6.8 g/dL, platelet count myeloid blasts.
    [Show full text]
  • Involvement of Nucleotide Excision and Mismatch Repair Mechanisms in Double Strand Break Repair
    250 Current Genomics, 2009, 10, 250-258 Involvement of Nucleotide Excision and Mismatch Repair Mechanisms in Double Strand Break Repair Ye Zhang1,2,*, Larry H. Rohde2 and Honglu Wu1 1NASA Johnson Space Center, Houston, Texas 77058 and 2University of Houston at Clear Lake, Houston, Texas 77058, USA Abstract: Living organisms are constantly threatened by environmental DNA-damaging agents, including UV and ioniz- ing radiation (IR). Repair of various forms of DNA damage caused by IR is normally thought to follow lesion-specific re- pair pathways with distinct enzymatic machinery. DNA double strand break is one of the most serious kinds of damage induced by IR, which is repaired through double strand break (DSB) repair mechanisms, including homologous recombi- nation (HR) and non-homologous end joining (NHEJ). However, recent studies have presented increasing evidence that various DNA repair pathways are not separated, but well interlinked. It has been suggested that non-DSB repair mecha- nisms, such as Nucleotide Excision Repair (NER), Mismatch Repair (MMR) and cell cycle regulation, are highly involved in DSB repairs. These findings revealed previously unrecognized roles of various non-DSB repair genes and indicated that a successful DSB repair requires both DSB repair mechanisms and non-DSB repair systems. One of our recent studies found that suppressed expression of non-DSB repair genes, such as XPA, RPA and MLH1, influenced the yield of IR- induced micronuclei formation and/or chromosome aberrations, suggesting that these genes are highly involved in DSB repair and DSB-related cell cycle arrest, which reveals new roles for these gene products in the DNA repair network.
    [Show full text]
  • Male Factor Infertility and Health Karen Baker, MD Associate Professor Duke University, Division of Urology Fertility And…
    Male Factor Infertility and Health Karen Baker, MD Associate Professor Duke University, Division of Urology Fertility and… • Cancer • Goals: • Heart disease • Review literature linking MFI to poor health • Metabolic syndrome • Diabetes • Discuss possible mechanisms common to MFI and cancer • Early death Cardiovascular risk • 3.5 million AARP members surveyed 1995-1996 • 137,903 men met criteria • 92% +paternity • mean age 62.7 yrs • 96.4% white • Age adjusted cardiovascular mortality risk 2.7/1000 person- years • Childless men 17%↑ cardiovascular mortality compared with men with + paternity Eisenberg, Hum Repro 2011 Cardiovascular risk • 3.5 million AARP members surveyed 1995-1996 • 137,903 men met criteria • 92% +paternity • mean age 62.7 yrs • 96.4% white • Age adjusted cardiovascular mortality risk 2.7/1000 person- years • Childless men 17%↑ cardiovascular mortality compared with men with + paternity Eisenberg, Hum Repro 2011 Chronic disease • Insurance claims 2001 - 2009 • 13,027 infertile men • Semen testing + MFI dx • 23,860 fertile men • Semen testing no MFI dx • 79,099 vasectomy • Age • Smoking by ICD9 • Obesity • Compared rates of common medical conditions • HTN, DM, peripheral vascular disease, cerebrovascular disease, ischemic heart by ICD9 disease, alcohol abuse, bipolar, etc. Chronic disease • ↑ medical disease in MFI vs Risk of developing chronic medical dz after dx MFI “semen testing” and vasectomies • DM HR 1.81 (95%CI 1.57-2.08) • Renal dz HR 1.6 (95%CI 1..14- 2.24) • Peripheral vascular dz HR 1.52 (95% CI 1.12-2.07) •
    [Show full text]
  • Evidence for Msh2haploinsufficiency in Mice Revealed by MNU
    British Journal of Cancer (2000) 83(10), 1291–1294 © 2000 Cancer Research Campaign doi: 10.1054/ bjoc.2000.1422, available online at http://www.idealibrary.com on Short Communication Evidence for Msh2 haploinsufficiency in mice revealed by MNU-induced sister-chromatid exchange analysis SD Bouffler1, N Hofland2, R Cox1 and R Fodde2 1Radiation Effects Department, National Radiological Protection Board, Chilton, Didcot, Oxfordshire, OX11 0RQ, UK; 2Department of Human and Clinical Genetics, Leiden University Medical Center, PO Box 9503, 2300 RA Leiden, The Netherlands Summary The role of Msh2 in chromosome stability has been investigated in a targeted mouse model for HNPCC, Msh2∆7N. Chromosome aberration frequencies were similar in bone marrow of Msh2+/+, Msh2+/– and Msh2–/– mice and no differential effects of in vivo X-irradiation were noted. By contrast, the induction of sister-chromatid exchanges (SCEs) by methyl nitrosourea (MNU) was reduced in Msh2–/– and Msh2+/– cells to ~20% and ~45% wild-type levels respectively indicating a phenotypic effect of haploinsufficiency of the mouse Msh2 gene. © 2000 Cancer Research Campaign Keywords Msh2; mismatch repair; alkylating agent; ionizing radiation; sister-chromatid exchange Human individuals carrying a mutation in the mismatch repair mice develop lymphomas at high frequency and also tumours of gene MSH2 are at increased risk of developing tumours in the the small bowel at lower incidence (deWind et al, 1995, 1998; colon and endometrium (Leach et al, 1993; Kolodner et al, 1994). Reitmair et al, 1995, 1996). Survival of Msh2+/– mice is compa- Tumours which develop in these patients display microsatellite rable to that of wild type animals although some evidence suggests instability (MSI) characterized by mutations at microsatellite and that tumours contribute disproportionately to the mortality of other simple sequence repeat loci (Aaltonen et al, 1993; Ionov heterozygotes (deWind et al, 1998).
    [Show full text]