1
|
Du D, Yang Y, Zhang Y, Wang G, Chen L, Guan X, Rasmussen LJ, Liu D. MRE11A: a novel negative regulator of human DNA mismatch repair. Cell Mol Biol Lett 2024; 29:37. [PMID: 38486171 PMCID: PMC10938699 DOI: 10.1186/s11658-024-00547-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/08/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND DNA mismatch repair (MMR) is a highly conserved pathway that corrects DNA replication errors, the loss of which is attributed to the development of various types of cancers. Although well characterized, MMR factors remain to be identified. As a 3'-5' exonuclease and endonuclease, meiotic recombination 11 homolog A (MRE11A) is implicated in multiple DNA repair pathways. However, the role of MRE11A in MMR is unclear. METHODS Initially, short-term and long-term survival assays were used to measure the cells' sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Meanwhile, the level of apoptosis was also determined by flow cytometry after MNNG treatment. Western blotting and immunofluorescence assays were used to evaluate the DNA damage within one cell cycle after MNNG treatment. Next, a GFP-heteroduplex repair assay and microsatellite stability test were used to measure the MMR activities in cells. To investigate the mechanisms, western blotting, the GFP-heteroduplex repair assay, and chromatin immunoprecipitation were used. RESULTS We show that knockdown of MRE11A increased the sensitivity of HeLa cells to MNNG treatment, as well as the MNNG-induced DNA damage and apoptosis, implying a potential role of MRE11 in MMR. Moreover, we found that MRE11A was largely recruited to chromatin and negatively regulated the DNA damage signals within the first cell cycle after MNNG treatment. We also showed that knockdown of MRE11A increased, while overexpressing MRE11A decreased, MMR activity in HeLa cells, suggesting that MRE11A negatively regulates MMR activity. Furthermore, we show that recruitment of MRE11A to chromatin requires MLH1 and that MRE11A competes with PMS2 for binding to MLH1. This decreases PMS2 levels in whole cells and on chromatin, and consequently comprises MMR activity. CONCLUSIONS Our findings reveal that MRE11A is a negative regulator of human MMR.
Collapse
Affiliation(s)
- Demin Du
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yueyan Yang
- Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yuanyuan Zhang
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Guanxiong Wang
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Liying Chen
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xiaowei Guan
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Dekang Liu
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| |
Collapse
|
2
|
Lee CY, Cheng WF, Lin PH, Chen YL, Huang SH, Lei KH, Chang KY, Ko MY, Chi P. An activity-based functional test for identifying homologous recombination deficiencies across cancer types in real time. Cell Rep Med 2023; 4:101247. [PMID: 37863059 PMCID: PMC10694588 DOI: 10.1016/j.xcrm.2023.101247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/17/2023] [Accepted: 09/26/2023] [Indexed: 10/22/2023]
Abstract
Homologous recombination (HR)-mediated DNA repair is a prerequisite for maintaining genome stability. Cancer cells displaying HR deficiency (HRD) are selectively eliminated by poly(ADP-ribose) polymerase inhibitors (PARPis). To date, sequencing of HR-associated genes and analyzing genome instability have been used as clinical predictions for PARPi therapy. However, these genetic tests cannot reflect dynamic changes in the HR status. Here, we have developed a virus- and activity-based functional assay to quantify real-time HR activity directly. Instead of focusing on a few HR-associated genes, our functional assay detects endpoint HR activity and establishes an activity threshold for identifying HRD across cancer types, validated by PARPi sensitivity and BRCA status. Notably, this fluorescence-based assay can be applied to primary ovarian cancer cells from patients to reflect their level of HRD, which is associated with survival benefits. Thus, our work provides a functional test to predict the response of primary cancer cells to PARPis.
Collapse
Affiliation(s)
- Chih-Ying Lee
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Wen-Fang Cheng
- Department of Obstetrics & Gynecology, National Taiwan University Hospital, Taipei, Taiwan
| | - Po-Han Lin
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Li Chen
- Department of Obstetrics & Gynecology, National Taiwan University Hospital, Taipei, Taiwan
| | - Shih-Han Huang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Kai-Hang Lei
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Ko-Yu Chang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Min-Yu Ko
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
| |
Collapse
|
3
|
Fang M, Deibler SK, Nana AL, Vatsavayai SC, Banday S, Zhou Y, Almeida S, Weiss A, Brown RH, Seeley WW, Gao FB, Green MR. Loss of TDP-43 function contributes to genomic instability in amyotrophic lateral sclerosis. Front Neurosci 2023; 17:1251228. [PMID: 37849894 PMCID: PMC10577185 DOI: 10.3389/fnins.2023.1251228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/08/2023] [Indexed: 10/19/2023] Open
Abstract
A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the cytoplasmic mislocalization and aggregation of the DNA/RNA-binding protein TDP-43, but how loss of nuclear TDP-43 function contributes to ALS and FTD pathogenesis remains largely unknown. Here, using large-scale RNAi screening, we identify TARDBP, which encodes TDP-43, as a gene whose loss-of-function results in elevated DNA mutation rate and genomic instability. Consistent with this finding, we observe increased DNA damage in induced pluripotent stem cells (iPSCs) and iPSC-derived post-mitotic neurons generated from ALS patients harboring TARDBP mutations. We find that the increase in DNA damage in ALS iPSC-derived neurons is due to defects in two major pathways for DNA double-strand break repair: non-homologous end joining and homologous recombination. Cells with defects in DNA repair are sensitive to DNA damaging agents and, accordingly, we find that ALS iPSC-derived neurons show a marked reduction in survival following treatment with a DNA damaging agent. Importantly, we find that increased DNA damage is also observed in neurons with nuclear TDP-43 depletion from ALS/FTD patient brain tissues. Collectively, our results demonstrate that ALS neurons with loss of nuclear TDP-43 function have elevated levels of DNA damage and contribute to the idea that genomic instability is a defining pathological feature of ALS/FTD patients with TDP-43 pathology.
Collapse
Affiliation(s)
- Minggang Fang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Sara K. Deibler
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Alissa L. Nana
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Sarat C. Vatsavayai
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Shahid Banday
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - You Zhou
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Alexandra Weiss
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Robert H. Brown
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - William W. Seeley
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Michael R. Green
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| |
Collapse
|
4
|
Manils J, Marruecos L, Soler C. Exonucleases: Degrading DNA to Deal with Genome Damage, Cell Death, Inflammation and Cancer. Cells 2022; 11:cells11142157. [PMID: 35883600 PMCID: PMC9316158 DOI: 10.3390/cells11142157] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/30/2022] [Accepted: 07/07/2022] [Indexed: 01/27/2023] Open
Abstract
Although DNA degradation might seem an unwanted event, it is essential in many cellular processes that are key to maintaining genomic stability and cell and organism homeostasis. The capacity to cut out nucleotides one at a time from the end of a DNA chain is present in enzymes called exonucleases. Exonuclease activity might come from enzymes with multiple other functions or specialized enzymes only dedicated to this function. Exonucleases are involved in central pathways of cell biology such as DNA replication, repair, and death, as well as tuning the immune response. Of note, malfunctioning of these enzymes is associated with immune disorders and cancer. In this review, we will dissect the impact of DNA degradation on the DNA damage response and its links with inflammation and cancer.
Collapse
Affiliation(s)
- Joan Manils
- Serra Húnter Programme, Immunology Unit, Department of Pathology and Experimental Therapy, School of Medicine, Universitat de Barcelona, Feixa Llarga s/n, 08907 L’Hospitalet de Llobregat, Spain;
- Immunity, Inflammation and Cancer Group, Oncobell Program, Institut d’Investigació Biomèdica de Bellvitge—IDIBELL, 08907 L’Hospitalet de Llobregat, Spain
| | - Laura Marruecos
- Breast Cancer Laboratory, Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia;
| | - Concepció Soler
- Immunity, Inflammation and Cancer Group, Oncobell Program, Institut d’Investigació Biomèdica de Bellvitge—IDIBELL, 08907 L’Hospitalet de Llobregat, Spain
- Immunology Unit, Department of Pathology and Experimental Therapy, School of Medicine, Universitat de Barcelona, 08007 Barcelona, Spain
- Correspondence:
| |
Collapse
|
5
|
Spectrum of DNA mismatch repair failures viewed through the lens of cancer genomics and implications for therapy. Clin Sci (Lond) 2022; 136:383-404. [PMID: 35274136 PMCID: PMC8919091 DOI: 10.1042/cs20210682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/02/2022] [Accepted: 02/28/2022] [Indexed: 12/15/2022]
Abstract
Genome sequencing can be used to detect DNA repair failures in tumors and learn about underlying mechanisms. Here, we synthesize findings from genomic studies that examined deficiencies of the DNA mismatch repair (MMR) pathway. The impairment of MMR results in genome-wide hypermutation and in the ‘microsatellite instability’ (MSI) phenotype—occurrence of indel mutations at short tandem repeat (microsatellite) loci. The MSI status of tumors was traditionally assessed by molecular testing of a selected set of MS loci or by measuring MMR protein expression levels. Today, genomic data can provide a more complete picture of the consequences on genomic instability. Multiple computational studies examined somatic mutation distributions that result from failed DNA repair pathways in tumors. These include analyzing the commonly studied trinucleotide mutational spectra of single-nucleotide variants (SNVs), as well as of other features such as indels, structural variants, mutation clusters and regional mutation rate redistribution. The identified mutation patterns can be used to rigorously measure prevalence of MMR failures across cancer types, and potentially to subcategorize the MMR deficiencies. Diverse data sources, genomic and pre-genomic, from human and from experimental models, suggest there are different ways in which MMR can fail, and/or that the cell-type or genetic background may result in different types of MMR mutational patterns. The spectrum of MMR failures may direct cancer evolution, generating particular sets of driver mutations. Moreover, MMR affects outcomes of therapy by DNA damaging drugs, antimetabolites, nonsense-mediated mRNA decay (NMD) inhibitors, and immunotherapy by promoting either resistance or sensitivity, depending on the type of therapy.
Collapse
|
6
|
Tarapara B, Shah F. An in-silico analysis to identify structural, functional and regulatory role of SNPs in hMRE11. J Biomol Struct Dyn 2022; 41:2160-2174. [PMID: 35048780 DOI: 10.1080/07391102.2022.2028678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Meiotic recombination 11 (MRE11) is a component of the tri-molecular MRE11-RAD50-NBS1 (MRN) complex, which functions as an exonuclease and endonuclease which is involved in identifying, signalling, protecting and repairing double-strand breaks in DNA (DSBs). Ataxia-telangiectasia-like disorder (ATLD) 1 and Nijmegen breakage syndrome (NBS)-like disorder are MRE11 associated diseases. In the present study, we used an integrated computational approach to identify the most deleterious SNPs and their structural and functional impact on human MRE11. Five of the 68 observed non-synonymous SNP (nsSNPs; I162T, S273C, W210C, D311Y and R364L) should be worked on due to their strong possible pathogenicity and the risk of changing protein properties. All the nsSNPs were highly conserved and decrease the protein stability located in the MRE11 nuclease and MRE11 DNA binding presumed domain. R364L and I162T were predicted to be involved in post-translational modification (PTM) sites. Furthermore, we also analysed the regulatory effect of noncoding SNPs on MRE11 gene regulation in which 6 SNPs were found to affect gene regulation. All six noncoding SNPs predicted chromatin interactive site whereas only one SNP was noted its association with miRNA binding site which disrupts 5 miRNA conserved site. These findings help future studies to get more insights into the role of these variants in the alteration of the MRE11 function. Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Bhoomi Tarapara
- Department of Cancer Biology, Stem Cell Biology Lab, The Gujarat Cancer and Research Institute, Ahmedabad, India
| | - Franky Shah
- Department of Cancer Biology, Stem Cell Biology Lab, The Gujarat Cancer and Research Institute, Ahmedabad, India
| |
Collapse
|
7
|
NBS1 I171V variant underlies individual differences in chromosomal radiosensitivity within human populations. Sci Rep 2021; 11:19661. [PMID: 34608183 PMCID: PMC8490386 DOI: 10.1038/s41598-021-98673-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 09/13/2021] [Indexed: 02/02/2023] Open
Abstract
Genetic information is protected against a variety of genotoxins including ionizing radiation (IR) through the DNA double-strand break (DSB) repair machinery. Genome-wide association studies and clinical sequencing of cancer patients have suggested that a number of variants in the DNA DSB repair genes might underlie individual differences in chromosomal radiosensitivity within human populations. However, the number of established variants that directly affect radiosensitivity is still limited. In this study, we performed whole-exome sequencing of 29 Japanese ovarian cancer patients and detected the NBS1 I171V variant, which is estimated to exist at a rate of approximately 0.15% in healthy human populations, in one patient. To clarify whether this variant indeed contributes to chromosomal radiosensitivity, we generated NBS1 I171V variant homozygous knock-in HCT116 cells and mice using the CRISPR/Cas9 system. Radiation-induced micronucleus formation and chromosomal aberration frequency were significantly increased in both HCT116 cells and mouse embryonic fibroblasts (MEFs) with knock-in of the NBS1 I171V variant compared with the levels in wild-type cells. These results suggested that the NBS1 I171V variant might be a genetic factor underlying individual differences in chromosomal radiosensitivity.
Collapse
|
8
|
Bahreyni-Toossi MT, Azimian H, Aghaee-Bakhtiari SH, Mahmoudi M, Sadat-Darbandi M, Zafari N. Radiation-induced DNA damage and altered expression of p21, cyclin D1 and Mre11 genes in human fibroblast cell lines with different radiosensitivity. Mutat Res 2021; 823:111760. [PMID: 34390933 DOI: 10.1016/j.mrfmmm.2021.111760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/26/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Radiotherapy plays a pivotal role in the treatment of cancer. One of the main challenges in this treatment modality is radiation-induced complications in some patients affected by high radiosensitivity (RS). The differences in RS are determined mainly by genetic factors. Therefore, identifying the genes and mechanisms that affect RS in different cells is essential for evaluating radiotherapy outcomes. In the present study, the ability to repair DNA double-stranded breaks (DSB) is evaluated, followed by examining the expression levels of CDKN1A (p21), cyclinD1, and Mre11 genes in human fibroblasts with different RSs. MATERIALS & METHODS Cellular RS was measured by survival fraction at 2 Gy (SF2). The γ-H2AX assay was used for assessing DNA repair capacity. Eventually, gene expression levels from each cell line 4 and 24 h after irradiation (at 2, 4, and 8 Gy) were measured by real-time PCR. RESULTS The SF2 values for the cell lines ranged from 0.286 to 0.641, and RS differences of fibroblast cells were identified. Among the studied genes, the expression of Mre11 was the most important. Analysis of the real-time PCR data showed that changes in Mre11 gene expression (4 h after 8 Gy irradiation) were directly correlated with the RS (R2 = 0.905). The difference in the expression of the p21 gene (4 h after 4 Gy irradiation) was also promising. Finally, the flow cytometry analysis showed that the radioresistant cell lines quickly repaired DBS damages. However, the repair process was slow in the radiosensitive cell line, and the residual damage is significantly higher than other cell lines (P < 0.01). CONCLUSIONS This study indicates that changes in the expression of p21 and Mre11 genes play an important role in cell response to radiation and thus these genes can be introduced as biomarkers to predict RS in normal cell lines.
Collapse
Affiliation(s)
| | - Hosein Azimian
- Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Mahmoud Mahmoudi
- Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahdi Sadat-Darbandi
- Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
| | - Navid Zafari
- Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
| |
Collapse
|
9
|
Tomasini PP, Guecheva TN, Leguisamo NM, Péricart S, Brunac AC, Hoffmann JS, Saffi J. Analyzing the Opportunities to Target DNA Double-Strand Breaks Repair and Replicative Stress Responses to Improve Therapeutic Index of Colorectal Cancer. Cancers (Basel) 2021; 13:3130. [PMID: 34201502 PMCID: PMC8268241 DOI: 10.3390/cancers13133130] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 12/22/2022] Open
Abstract
Despite the ample improvements of CRC molecular landscape, the therapeutic options still rely on conventional chemotherapy-based regimens for early disease, and few targeted agents are recommended for clinical use in the metastatic setting. Moreover, the impact of cytotoxic, targeted agents, and immunotherapy combinations in the metastatic scenario is not fully satisfactory, especially the outcomes for patients who develop resistance to these treatments need to be improved. Here, we examine the opportunity to consider therapeutic agents targeting DNA repair and DNA replication stress response as strategies to exploit genetic or functional defects in the DNA damage response (DDR) pathways through synthetic lethal mechanisms, still not explored in CRC. These include the multiple actors involved in the repair of DNA double-strand breaks (DSBs) through homologous recombination (HR), classical non-homologous end joining (NHEJ), and microhomology-mediated end-joining (MMEJ), inhibitors of the base excision repair (BER) protein poly (ADP-ribose) polymerase (PARP), as well as inhibitors of the DNA damage kinases ataxia-telangiectasia and Rad3 related (ATR), CHK1, WEE1, and ataxia-telangiectasia mutated (ATM). We also review the biomarkers that guide the use of these agents, and current clinical trials with targeted DDR therapies.
Collapse
Affiliation(s)
- Paula Pellenz Tomasini
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
| | - Temenouga Nikolova Guecheva
- Cardiology Institute of Rio Grande do Sul, University Foundation of Cardiology (IC-FUC), Porto Alegre 90620-000, Brazil;
| | - Natalia Motta Leguisamo
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
| | - Sarah Péricart
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Anne-Cécile Brunac
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jean Sébastien Hoffmann
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jenifer Saffi
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
| |
Collapse
|
10
|
A Survey of Reported Disease-Related Mutations in the MRE11-RAD50-NBS1 Complex. Cells 2020; 9:cells9071678. [PMID: 32668560 PMCID: PMC7407228 DOI: 10.3390/cells9071678] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 12/24/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) protein complex is one of the primary vehicles for repairing DNA double strand breaks and maintaining the genomic stability within the cell. The role of the MRN complex to recognize and process DNA double-strand breaks as well as signal other damage response factors is critical for maintaining proper cellular function. Mutations in any one of the components of the MRN complex that effect function or expression of the repair machinery could be detrimental to the cell and may initiate and/or propagate disease. Here, we discuss, in a structural and biochemical context, mutations in each of the three MRN components that have been associated with diseases such as ataxia telangiectasia-like disorder (ATLD), Nijmegen breakage syndrome (NBS), NBS-like disorder (NBSLD) and certain types of cancers. Overall, deepening our understanding of disease-causing mutations of the MRN complex at the structural and biochemical level is foundational to the future aim of treating diseases associated with these aberrations.
Collapse
|
11
|
Bennett LG, Wilkie AM, Antonopoulou E, Ceppi I, Sanchez A, Vernon EG, Gamble A, Myers KN, Collis SJ, Cejka P, Staples CJ. MRNIP is a replication fork protection factor. SCIENCE ADVANCES 2020; 6:eaba5974. [PMID: 32832601 PMCID: PMC7439443 DOI: 10.1126/sciadv.aba5974] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/28/2020] [Indexed: 05/04/2023]
Abstract
The remodeling of stalled replication forks to form four-way DNA junctions is an important component of the replication stress response. Nascent DNA at the regressed arms of these reversed forks is protected by RAD51 and the tumor suppressors BRCA1/2, and when this function is compromised, stalled forks undergo pathological MRE11-dependent degradation, leading to chromosomal instability. However, the mechanisms regulating MRE11 functions at reversed forks are currently unclear. Here, we identify the MRE11-binding protein MRNIP as a novel fork protection factor that directly binds to MRE11 and specifically represses its exonuclease activity. The loss of MRNIP results in impaired replication fork progression, MRE11 exonuclease-dependent degradation of reversed forks, persistence of underreplicated genomic regions, chemosensitivity, and chromosome instability. Our findings identify MRNIP as a novel regulator of MRE11 at reversed forks and provide evidence that regulation of specific MRE11 nuclease activities ensures protection of nascent DNA and thereby genome integrity.
Collapse
Affiliation(s)
- L. G. Bennett
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - A. M. Wilkie
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - E. Antonopoulou
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - I. Ceppi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
- Institute of Biochemistry, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - A. Sanchez
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
| | - E. G. Vernon
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - A. Gamble
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - K. N. Myers
- Sheffield Institute for Nucleic Acids, Department of Oncology and Metabolism, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - S. J. Collis
- Sheffield Institute for Nucleic Acids, Department of Oncology and Metabolism, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - P. Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
- Institute of Biochemistry, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - C. J. Staples
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| |
Collapse
|
12
|
Sun Y, Saha S, Wang W, Saha LK, Huang SYN, Pommier Y. Excision repair of topoisomerase DNA-protein crosslinks (TOP-DPC). DNA Repair (Amst) 2020; 89:102837. [PMID: 32200233 DOI: 10.1016/j.dnarep.2020.102837] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 12/13/2022]
Abstract
Topoisomerases are essential enzymes solving DNA topological problems such as supercoils, knots and catenanes that arise from replication, transcription, chromatin remodeling and other nucleic acid metabolic processes. They are also the targets of widely used anticancer drugs (e.g. topotecan, irinotecan, enhertu, etoposide, doxorubicin, mitoxantrone) and fluoroquinolone antibiotics (e.g. ciprofloxacin and levofloxacin). Topoisomerases manipulate DNA topology by cleaving one DNA strand (TOP1 and TOP3 enzymes) or both in concert (TOP2 enzymes) through the formation of transient enzyme-DNA cleavage complexes (TOPcc) with phosphotyrosyl linkages between DNA ends and the catalytic tyrosyl residue of the enzymes. Failure in the self-resealing of TOPcc results in persistent TOPcc (which we refer it to as topoisomerase DNA-protein crosslinks (TOP-DPC)) that threaten genome integrity and lead to cancers and neurodegenerative diseases. The cell prevents the accumulation of topoisomerase-mediated DNA damage by excising TOP-DPC and ligating the associated breaks using multiple pathways conserved in eukaryotes. Tyrosyl-DNA phosphodiesterases (TDP1 and TDP2) cleave the tyrosyl-DNA bonds whereas structure-specific endonucleases such as Mre11 and XPF (Rad1) incise the DNA phosphodiester backbone to remove the TOP-DPC along with the adjacent DNA segment. The proteasome and metalloproteases of the WSS1/Spartan family typify proteolytic repair pathways that debulk TOP-DPC to make the peptide-DNA bonds accessible to the TDPs and endonucleases. The purpose of this review is to summarize our current understanding of how the cell excises TOP-DPC and why, when and where the cell recruits one specific mechanism for repairing topoisomerase-mediated DNA damage, acquiring resistance to therapeutic topoisomerase inhibitors and avoiding genomic instability, cancers and neurodegenerative diseases.
Collapse
Affiliation(s)
- Yilun Sun
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Sourav Saha
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Wenjie Wang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Liton Kumar Saha
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
| |
Collapse
|
13
|
Kawale AS, Povirk LF. Tyrosyl-DNA phosphodiesterases: rescuing the genome from the risks of relaxation. Nucleic Acids Res 2019; 46:520-537. [PMID: 29216365 PMCID: PMC5778467 DOI: 10.1093/nar/gkx1219] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 11/29/2017] [Indexed: 12/13/2022] Open
Abstract
Tyrosyl–DNA Phosphodiesterases 1 (TDP1) and 2 (TDP2) are eukaryotic enzymes that clean-up after aberrant topoisomerase activity. While TDP1 hydrolyzes phosphotyrosyl peptides emanating from trapped topoisomerase I (Top I) from the 3′ DNA ends, topoisomerase 2 (Top II)-induced 5′-phosphotyrosyl residues are processed by TDP2. Even though the canonical functions of TDP1 and TDP2 are complementary, they exhibit little structural or sequence similarity. Homozygous mutations in genes encoding these enzymes lead to the development of severe neurodegenerative conditions due to the accumulation of transcription-dependent topoisomerase cleavage complexes underscoring the biological significance of these enzymes in the repair of topoisomerase–DNA lesions in the nervous system. TDP1 can promiscuously process several blocked 3′ ends generated by DNA damaging agents and nucleoside analogs in addition to hydrolyzing 3′-phosphotyrosyl residues. In addition, deficiency of these enzymes causes hypersensitivity to anti-tumor topoisomerase poisons. Thus, TDP1 and TDP2 are promising therapeutic targets and their inhibitors are expected to significantly synergize the effects of current anti-tumor therapies including topoisomerase poisons and other DNA damaging agents. This review covers the structural aspects, biology and regulation of these enzymes, along with ongoing developments in the process of discovering safe and effective TDP inhibitors.
Collapse
Affiliation(s)
- Ajinkya S Kawale
- Department of Pharmacology and Toxicology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Lawrence F Povirk
- Department of Pharmacology and Toxicology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| |
Collapse
|
14
|
Taheri-Ghahfarokhi A, Taylor BJ, Nitsch R, Lundin A, Cavallo AL, Madeyski-Bengtson K, Karlsson F, Clausen M, Hicks R, Mayr LM, Bohlooly-Y M, Maresca M. Decoding non-random mutational signatures at Cas9 targeted sites. Nucleic Acids Res 2018; 46:8417-8434. [PMID: 30032200 PMCID: PMC6144780 DOI: 10.1093/nar/gky653] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
The mutation patterns at Cas9 targeted sites contain unique information regarding the nuclease activity and repair mechanisms in mammalian cells. However, analytical framework for extracting such information are lacking. Here, we present a novel computational platform called Rational InDel Meta-Analysis (RIMA) that enables an in-depth comprehensive analysis of Cas9-induced genetic alterations, especially InDels mutations. RIMA can be used to quantitate the contribution of classical microhomology-mediated end joining (c-MMEJ) pathway in the formation of mutations at Cas9 target sites. We used RIMA to compare mutational signatures at 15 independent Cas9 target sites in human A549 wildtype and A549-POLQ knockout cells to elucidate the role of DNA polymerase θ in c-MMEJ. Moreover, the single nucleotide insertions at the Cas9 target sites represent duplications of preceding nucleotides, suggesting that the flexibility of the Cas9 nuclease domains results in both blunt- and staggered-end cuts. Thymine at the fourth nucleotide before protospacer adjacent motif (PAM) results in a two-fold higher occurrence of single nucleotide InDels compared to guanine at the same position. This study provides a novel approach for the characterization of the Cas9 nucleases with improved accuracy in predicting genome editing outcomes and a potential strategy for homology-independent targeted genomic integration.
Collapse
Affiliation(s)
- Amir Taheri-Ghahfarokhi
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Benjamin J M Taylor
- Discovery Biology, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - Roberto Nitsch
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
- Advanced Medicines Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Anders Lundin
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Anna-Lina Cavallo
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Katja Madeyski-Bengtson
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Fredrik Karlsson
- Quantitative Biology, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Maryam Clausen
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Ryan Hicks
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Lorenz M Mayr
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
- GE Healthcare Life Sciences, The Grove Centre, White Lion Road, Amersham HP7 9LL, UK
| | - Mohammad Bohlooly-Y
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Marcello Maresca
- Translational Genomics, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| |
Collapse
|
15
|
The Tip of an Iceberg: Replication-Associated Functions of the Tumor Suppressor p53. Cancers (Basel) 2018; 10:cancers10080250. [PMID: 30060597 PMCID: PMC6115784 DOI: 10.3390/cancers10080250] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/16/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
The tumor suppressor p53 is a transcriptional factor broadly mutated in cancer. Most inactivating and gain of function mutations disrupt the sequence-specific DNA binding domain, which activates target genes. This is perhaps the main reason why most research has focused on the relevance of such transcriptional activity for the prevention or elimination of cancer cells. Notwithstanding, transcriptional regulation may not be the only mechanism underlying its role in tumor suppression and therapeutic responses. In the past, a direct role of p53 in DNA repair transactions that include the regulation of homologous recombination has been suggested. More recently, the localization of p53 at replication forks has been demonstrated and the effect of p53 on nascent DNA elongation has been explored. While some data sets indicate that the regulation of ongoing replication forks by p53 may be mediated by p53 targets such as MDM2 (murine double minute 2) and polymerase (POL) eta other evidences demonstrate that p53 is capable of controlling DNA replication by directly interacting with the replisome and altering its composition. In addition to discussing such findings, this review will also analyze the impact that p53-mediated control of ongoing DNA replication has on treatment responses and tumor suppressor abilities of this important anti-oncogene.
Collapse
|
16
|
Mirza-Aghazadeh-Attari M, Darband SG, Kaviani M, Mihanfar A, Aghazadeh Attari J, Yousefi B, Majidinia M. DNA damage response and repair in colorectal cancer: Defects, regulation and therapeutic implications. DNA Repair (Amst) 2018; 69:34-52. [PMID: 30055507 DOI: 10.1016/j.dnarep.2018.07.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/15/2018] [Accepted: 07/15/2018] [Indexed: 12/11/2022]
Abstract
DNA damage response, a key factor involved in maintaining genome integrity and stability, consists of several kinase-dependent signaling pathways, which sense and transduce DNA damage signal. The severity of damage appears to determine DNA damage responses, which can include cell cycle arrest, damage repair and apoptosis. A number of recent studies have demonstrated that defection in signaling through this network is thought to be an underlying mechanism behind the development and progression of various types of human malignancies, including colorectal cancer. In this review, colorectal cancer and its molecular pathology as well as DNA damage response is briefly introduced. Finally, the involvement of key components of this network in the initiation/progression, prognosis, response to treatment and development of drug resistance is comprehensively discussed.
Collapse
Affiliation(s)
- Mohammad Mirza-Aghazadeh-Attari
- Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saber Ghazizadeh Darband
- Danesh Pey Hadi Co., Health Technology Development Center, Urmia University of Medical Sciences, Urmia, Iran
| | - Mojtaba Kaviani
- School of Nutrition and Dietetics, Acadia University, Wolfville, Nova Scotia, Canada
| | - Ainaz Mihanfar
- Stem Cell and Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Bahman Yousefi
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Maryam Majidinia
- Solid Tumor Research Center, Urmia University of Medical Sciences, Urmia, Iran.
| |
Collapse
|
17
|
Romanova LY, Mushinski F, Kovalchuk AL. Transcriptional activation of p21 Waf1 contributes to suppression of HR by p53 in response to replication arrest induced by camptothecin. Oncotarget 2018; 9:25427-25440. [PMID: 29875999 PMCID: PMC5986631 DOI: 10.18632/oncotarget.25172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/21/2018] [Indexed: 11/25/2022] Open
Abstract
The inhibitory effect of p53 on homologous recombination (HR) is exerted through sequestration of replication protein A (RPA). Release of the p53/RPA complex in response to replication stress is crucially dependent on the phosphorylation status of both proteins and is required for efficient DNA repair by HR. Phosphorylation of RPA within its RPA2 subunit by cyclin-dependent kinases (CDK) is an early event in the replication stress response. Here we investigated the role of transcriptional activation of the p53 downstream target, p21Waf1, on RPA2 phosphorylation, the stability of the p53/RPA complex and HR in cells undergoing replication arrest induced by camptothecin (CPT). We show that in CPT-treated cells, activation of p53 and p21Waf1 impedes RPA2 phosphorylation, while their depletion by siRNA stimulates it. The p53/RPA complex is more stable in wild-type cells than in cells depleted of p21Waf1. We used nocodazole-synchronized cells treated with CPT at the entrance to S phase to assess rates of HR. Regardless of their p53 or p21Waf1 status, the cells proceed through S phase at a similar rate and enter G2. While HR is low in wild-type cells and high in p53-depleted cells, only partial inhibition of HR is observed in the p21Waf1-depleted cells. This correlates with the extent of RPA sequestration by p53. Thus, in CPT-treated cells, p53-induced transcriptional activation of p21Waf1 regulates RPA2 phosphorylation, the stability of the p53/RPA complex and HR.
Collapse
Affiliation(s)
- Larisa Y Romanova
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA.,The Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, USA
| | - Frederick Mushinski
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Alexander L Kovalchuk
- The Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, USA
| |
Collapse
|
18
|
Piscitello D, Varshney D, Lilla S, Vizioli MG, Reid C, Gorbunova V, Seluanov A, Gillespie DA, Adams PD. AKT overactivation can suppress DNA repair via p70S6 kinase-dependent downregulation of MRE11. Oncogene 2018; 37:427-438. [PMID: 28967905 PMCID: PMC5799716 DOI: 10.1038/onc.2017.340] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 07/22/2017] [Accepted: 08/14/2017] [Indexed: 02/07/2023]
Abstract
Deregulated AKT kinase activity due to PTEN deficiency in cancer cells contributes to oncogenesis by incompletely understood mechanisms. Here, we show that PTEN deletion in HCT116 and DLD1 colon carcinoma cells leads to suppression of CHK1 and CHK2 activation in response to irradiation, impaired G2 checkpoint proficiency and radiosensitization. These defects are associated with reduced expression of MRE11, RAD50 and NBS1, components of the apical MRE11/RAD50/NBS1 (MRN) DNA damage response complex. Consistent with reduced MRN complex function, PTEN-deficient cells fail to resect DNA double-strand breaks efficiently after irradiation and show greatly diminished proficiency for DNA repair via the error-free homologous recombination (HR) repair pathway. MRE11 is highly unstable in PTEN-deficient cells but stability can be significantly restored by inhibiting mTORC1 or p70S6 kinase (p70S6K), downstream kinases whose activities are stimulated by AKT, or by mutating a residue in MRE11 that we show is phosphorylated by p70S6K in vitro. In primary human fibroblasts, activated AKT suppresses MRN complex expression to escalate RAS-induced DNA damage and thereby reinforce oncogene-induced senescence. Taken together, our data demonstrate that deregulation of the PI3K-AKT/ mTORC1/ p70S6K pathways, an event frequently observed in cancer, exert profound effects on genome stability via MRE11 with potential implications for tumour initiation and therapy.
Collapse
Affiliation(s)
- D Piscitello
- Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK
| | - D Varshney
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - S Lilla
- Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK
| | - M G Vizioli
- Epigenetics of Cancer and Ageing, University of Glasgow, Glasgow, UK
| | - C Reid
- Epigenetics of Cancer and Ageing, University of Glasgow, Glasgow, UK
| | - V Gorbunova
- Department of Biology, University of Rochester, Rochester, NY, USA
| | - A Seluanov
- Department of Biology, University of Rochester, Rochester, NY, USA
| | - D A Gillespie
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Spain
| | - P D Adams
- Epigenetics of Cancer and Ageing, University of Glasgow, Glasgow, UK
| |
Collapse
|
19
|
Abramenkovs A, Stenerlöw B. Measurement of DNA-Dependent Protein Kinase Phosphorylation Using Flow Cytometry Provides a Reliable Estimate of DNA Repair Capacity. Radiat Res 2017; 188:597-604. [PMID: 28952912 DOI: 10.1667/rr14693.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Uncontrolled generation of DNA double-strand breaks (DSBs) in cells is regarded as a highly toxic event that threatens cell survival. Radiation-induced DNA DSBs are commonly measured by pulsed-field gel electrophoresis, microscopic evaluation of accumulating DNA damage response proteins (e.g., 53BP1 or γ-H2AX) or flow cytometric analysis of γ-H2AX. The advantage of flow cytometric analysis is that DSB formation and repair can be studied in relationship to cell cycle phase or expression of other proteins. However, γ-H2AX is not able to monitor repair kinetics within the first 60 min postirradiation, a period when most DSBs undergo repair. A key protein in non-homologous end joining repair is the catalytic subunit of DNA-dependent protein kinase. Among several phosphorylation sites of DNA-dependent protein kinase, the threonine at position 2609 (T2609), which is phosphorylated by ataxia telangiectasia mutated (ATM) or DNA-dependent protein kinase catalytic subunit itself, activates the end processing of DSB. Using flow cytometry, we show here that phosphorylation at T2609 is faster in response to DSBs than γ-H2AX. Furthermore, flow cytometric analysis of T2609 resulted in a better representation of fast repair kinetics than analysis of γ-H2AX. In cells with reduced ligase IV activity, and wild-type cells where DNA-dependent protein kinase activity was inhibited, the reduced DSB repair capacity was observed by T2609 evaluation using flow cytometry. In conclusion, flow cytometric evaluation of DNA-dependent protein kinase T2609 can be used as a marker for early DSB repair and gives a better representation of early repair events than analysis of γ-H2AX.
Collapse
Affiliation(s)
- Andris Abramenkovs
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Bo Stenerlöw
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden
| |
Collapse
|
20
|
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.
Collapse
|
21
|
Nicholson J, Jevons SJ, Groselj B, Ellermann S, Konietzny R, Kerr M, Kessler BM, Kiltie AE. E3 Ligase cIAP2 Mediates Downregulation of MRE11 and Radiosensitization in Response to HDAC Inhibition in Bladder Cancer. Cancer Res 2017; 77:3027-3039. [PMID: 28363998 DOI: 10.1158/0008-5472.can-16-3232] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/10/2017] [Accepted: 03/27/2017] [Indexed: 11/16/2022]
Abstract
The MRE11/RAD50/NBS1 (MRN) complex mediates DNA repair pathways, including double-strand breaks induced by radiotherapy. Meiotic recombination 11 homolog (MRE11) is downregulated by histone deacetylase inhibition (HDACi), resulting in reduced levels of DNA repair in bladder cancer cells and radiosensitization. In this study, we show that the mechanism of this downregulation is posttranslational and identify a C-terminally truncated MRE11, which is formed after HDAC inhibition as full-length MRE11 is downregulated. Truncated MRE11 was stabilized by proteasome inhibition, exhibited a decreased half-life after treatment with panobinostat, and therefore represents a newly identified intermediate induced and degraded in response to HDAC inhibition. The E3 ligase cellular inhibitor of apoptosis protein 2 (cIAP2) was upregulated in response to HDAC inhibition and was validated as a new MRE11 binding partner whose upregulation had similar effects to HDAC inhibition. cIAP2 overexpression resulted in downregulation and altered ubiquitination patterns of MRE11 and mediated radiosensitization in response to HDAC inhibition. These results highlight cIAP2 as a player in the DNA damage response as a posttranscriptional regulator of MRE11 and identify cIAP2 as a potential target for biomarker discovery or chemoradiation strategies in bladder cancer. Cancer Res; 77(11); 3027-39. ©2017 AACR.
Collapse
Affiliation(s)
- Judith Nicholson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom.
| | - Sarah J Jevons
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Blaz Groselj
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Sophie Ellermann
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Rebecca Konietzny
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Martin Kerr
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Anne E Kiltie
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
22
|
Deeg KI, Chung I, Bauer C, Rippe K. Cancer Cells with Alternative Lengthening of Telomeres Do Not Display a General Hypersensitivity to ATR Inhibition. Front Oncol 2016; 6:186. [PMID: 27602331 PMCID: PMC4993795 DOI: 10.3389/fonc.2016.00186] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/05/2016] [Indexed: 01/20/2023] Open
Abstract
Telomere maintenance is a hallmark of cancer as it provides cancer cells with cellular immortality. A significant fraction of tumors uses the alternative lengthening of telomeres (ALT) pathway to elongate their telomeres and to gain an unlimited proliferation potential. Since the ALT pathway is unique to cancer cells, it represents a potentially valuable, currently unexploited target for anti-cancer therapies. Recently, it was proposed that ALT renders cells hypersensitive to ataxia telangiectasia- and RAD3-related (ATR) protein inhibitors (Flynn et al., Science 347, 273). Here, we measured the response of various ALT- or telomerase-positive cell lines to the ATR inhibitor VE-821. In addition, we compared the effect of the inhibitor on cell viability in isogenic cell lines, in which ALT was active or suppressed. In these experiments, a general ATR inhibitor sensitivity of cells with ALT could not be confirmed. We rather propose that the observed variations in sensitivity reflect differences between cell lines that are unrelated to ALT.
Collapse
Affiliation(s)
- Katharina I Deeg
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Inn Chung
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Caroline Bauer
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Karsten Rippe
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| |
Collapse
|
23
|
Stadler ZK. Diagnosis and management of DNA mismatch repair-deficient colorectal cancer. Hematol Oncol Clin North Am 2015; 29:29-41. [PMID: 25475571 DOI: 10.1016/j.hoc.2014.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Colorectal tumors exhibiting defective DNA mismatch repair (MMR-D)/microsatellite instability (MSI-H) form a distinct subgroup of CRCs associated with important clinical and pathologic features. The identification of MMR-D/MSI-H may impact CRC prognosis, prediction of response to chemotherapeutic agents, and may necessitate the need for genetic assessment for Lynch syndrome. Oncologists remain at the forefront of diagnosing, treating, and managing patients with MMR-D/MSI-H CRC and ensuring that the clinical care of these patients reflect our evolving understanding of this unique CRC subtype.
Collapse
Affiliation(s)
- Zsofia K Stadler
- Clinical Genetics Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| |
Collapse
|
24
|
Xu Y, Her C. Inhibition of Topoisomerase (DNA) I (TOP1): DNA Damage Repair and Anticancer Therapy. Biomolecules 2015; 5:1652-70. [PMID: 26287259 PMCID: PMC4598769 DOI: 10.3390/biom5031652] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/14/2015] [Indexed: 12/31/2022] Open
Abstract
Most chemotherapy regimens contain at least one DNA-damaging agent that preferentially affects the growth of cancer cells. This strategy takes advantage of the differences in cell proliferation between normal and cancer cells. Chemotherapeutic drugs are usually designed to target rapid-dividing cells because sustained proliferation is a common feature of cancer [1,2]. Rapid DNA replication is essential for highly proliferative cells, thus blocking of DNA replication will create numerous mutations and/or chromosome rearrangements—ultimately triggering cell death [3]. Along these lines, DNA topoisomerase inhibitors are of great interest because they help to maintain strand breaks generated by topoisomerases during replication. In this article, we discuss the characteristics of topoisomerase (DNA) I (TOP1) and its inhibitors, as well as the underlying DNA repair pathways and the use of TOP1 inhibitors in cancer therapy.
Collapse
Affiliation(s)
- Yang Xu
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Mail Drop 64-7520, Pullman, WA 99164, USA.
| | - Chengtao Her
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Mail Drop 64-7520, Pullman, WA 99164, USA.
| |
Collapse
|
25
|
XRCC4/XLF Interaction Is Variably Required for DNA Repair and Is Not Required for Ligase IV Stimulation. Mol Cell Biol 2015; 35:3017-28. [PMID: 26100018 DOI: 10.1128/mcb.01503-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 06/15/2015] [Indexed: 01/21/2023] Open
Abstract
The classic nonhomologous end-joining (c-NHEJ) pathway is largely responsible for repairing double-strand breaks (DSBs) in mammalian cells. XLF stimulates the XRCC4/DNA ligase IV complex by an unknown mechanism. XLF interacts with XRCC4 to form filaments of alternating XRCC4 and XLF dimers that bridge DNA ends in vitro, providing a mechanism by which XLF might stimulate ligation. Here, we characterize two XLF mutants that do not interact with XRCC4 and cannot form filaments or bridge DNA in vitro. One mutant is fully sufficient in stimulating ligation by XRCC4/Lig4 in vitro; the other is not. This separation-of-function mutant (which must function as an XLF homodimer) fully complements the c-NHEJ deficits of some XLF-deficient cell strains but not others, suggesting a variable requirement for XRCC4/XLF interaction in living cells. To determine whether the lack of XRCC4/XLF interaction (and potential bridging) can be compensated for by other factors, candidate repair factors were disrupted in XLF- or XRCC4-deficient cells. The loss of either ATM or the newly described XRCC4/XLF-like factor, PAXX, accentuates the requirement for XLF. However, in the case of ATM/XLF loss (but not PAXX/XLF loss), this reflects a greater requirement for XRCC4/XLF interaction.
Collapse
|
26
|
Laffitte MCN, Genois MM, Mukherjee A, Légaré D, Masson JY, Ouellette M. Formation of linear amplicons with inverted duplications in Leishmania requires the MRE11 nuclease. PLoS Genet 2014; 10:e1004805. [PMID: 25474106 PMCID: PMC4256157 DOI: 10.1371/journal.pgen.1004805] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/06/2014] [Indexed: 11/22/2022] Open
Abstract
Extrachromosomal DNA amplification is frequent in the protozoan parasite Leishmania selected for drug resistance. The extrachromosomal amplified DNA is either circular or linear, and is formed at the level of direct or inverted homologous repeated sequences that abound in the Leishmania genome. The RAD51 recombinase plays an important role in circular amplicons formation, but the mechanism by which linear amplicons are formed is unknown. We hypothesized that the Leishmania infantum DNA repair protein MRE11 is required for linear amplicons following rearrangements at the level of inverted repeats. The purified LiMRE11 protein showed both DNA binding and exonuclease activities. Inactivation of the LiMRE11 gene led to parasites with enhanced sensitivity to DNA damaging agents. The MRE11−/− parasites had a reduced capacity to form linear amplicons after drug selection, and the reintroduction of an MRE11 allele led to parasites regaining their capacity to generate linear amplicons, but only when MRE11 had an active nuclease activity. These results highlight a novel MRE11-dependent pathway used by Leishmania to amplify portions of its genome to respond to a changing environment. Extrachromosomal DNA amplification is frequent in the human protozoan parasite Leishmania when challenged with drug or other stressful conditions. DNA amplicons, either circular or linear, are formed by recombination between direct or inverted repeats spread throughout the genome of the parasite. The recombinase RAD51 is involved in the formation of circular amplicons, but the mechanism by which linear amplicons are formed is still unknown in this parasite. Studies in other organisms have provided some evidence that a DNA break is required for linear amplifications, and that the DNA repair protein MRE11 can be involved in this process. In this work, we present our biochemical, cellular and molecular characterization of the Leishmania infantum MRE11 orthologue and provide evidence that this nuclease is involved in the formation of linear amplicons in Leishmania. Our results highlight a novel MRE11-dependent pathway used by Leishmania to amplify portions of its genome to respond to a changing environment.
Collapse
Affiliation(s)
| | - Marie-Michelle Genois
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
- Genome Stability Laboratory, CHU de Quebec Research Center, HDQ Pavillon, Oncology Axis, Quebec City, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University, Quebec City, Québec, Canada
| | - Angana Mukherjee
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
| | - Danielle Légaré
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Quebec Research Center, HDQ Pavillon, Oncology Axis, Quebec City, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University, Quebec City, Québec, Canada
| | - Marc Ouellette
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
- * E-mail:
| |
Collapse
|
27
|
Pavelitz T, Renfro L, Foster NR, Caracol A, Welsch P, Lao VV, Grady WB, Niedzwiecki D, Saltz LB, Bertagnolli MM, Goldberg RM, Rabinovitch PS, Emond M, Monnat RJ, Maizels N. MRE11-deficiency associated with improved long-term disease free survival and overall survival in a subset of stage III colon cancer patients in randomized CALGB 89803 trial. PLoS One 2014; 9:e108483. [PMID: 25310185 PMCID: PMC4195600 DOI: 10.1371/journal.pone.0108483] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 08/19/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose Colon cancers deficient in mismatch repair (MMR) may exhibit diminished expression of the DNA repair gene, MRE11, as a consequence of contraction of a T11 mononucleotide tract. This study investigated MRE11 status and its association with prognosis, survival and drug response in patients with stage III colon cancer. Patients and Methods Cancer and Leukemia Group B 89803 (Alliance) randomly assigned 1,264 patients with stage III colon cancer to postoperative weekly adjuvant bolus 5-fluorouracil/leucovorin (FU/LV) or irinotecan+FU/LV (IFL), with 8 year follow-up. Tumors from these patients were analyzed to determine stability of a T11 tract in the MRE11 gene. The primary endpoint was overall survival (OS), and a secondary endpoint was disease-free survival (DFS). Non-proportional hazards were addressed using time-dependent covariates in Cox analyses. Results Of 625 tumor cases examined, 70 (11.2%) exhibited contraction at the T11 tract in one or both MRE11 alleles and were thus predicted to be deficient in MRE11 (dMRE11). In pooled treatment analyses, dMRE11 patients showed initially reduced DFS and OS but improved long-term DFS and OS compared with patients with an intact MRE11 T11 tract. In the subgroup of dMRE11 patients treated with IFL, an unexplained early increase in mortality but better long-term DFS than IFL-treated pMRE11 patients was observed. Conclusions Analysis of this relatively small number of patients and events showed that the dMRE11 marker predicts better prognosis independent of treatment in the long-term. In subgroup analyses, dMRE11 patients treated with irinotecan exhibited unexplained short-term mortality. MRE11 status is readily assayed and may therefore prove to be a useful prognostic marker, provided that the results reported here for a relatively small number of patients can be generalized in independent analyses of larger numbers of samples. Trial Registration ClinicalTrials.gov NCT00003835
Collapse
Affiliation(s)
- Thomas Pavelitz
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
- Department of Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Lindsay Renfro
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Nathan R. Foster
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Amber Caracol
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Piri Welsch
- Department of Genome Sciences, University of Washington Medical School, Seattle, Washington, United States of America
| | - Victoria Valinluck Lao
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Surgery, University of Washington Medical School, Seattle, Washington, United States of America
| | - William B. Grady
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Medicine, University of Washington Medical School, Seattle, Washington, United States of America
| | - Donna Niedzwiecki
- Cancer and Leukemia Group B Statistical Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Leonard B. Saltz
- Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Monica M. Bertagnolli
- Dana-Farber Cancer Institute and Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | | | - Peter S. Rabinovitch
- Department of Pathology, University of Washington Medical School, Seattle, Washington, United States of America
| | - Mary Emond
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Raymond J. Monnat
- Department of Genome Sciences, University of Washington Medical School, Seattle, Washington, United States of America
- Department of Pathology, University of Washington Medical School, Seattle, Washington, United States of America
| | - Nancy Maizels
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, United States of America
- Department of Pathology, University of Washington Medical School, Seattle, Washington, United States of America
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| |
Collapse
|
28
|
Martin RM, Kerr M, Teo MTW, Jevons SJ, Koritzinsky M, Wouters BG, Bhattarai S, Kiltie AE. Post-transcriptional regulation of MRE11 expression in muscle-invasive bladder tumours. Oncotarget 2014; 5:993-1003. [PMID: 24625413 PMCID: PMC4011600 DOI: 10.18632/oncotarget.1627] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/14/2014] [Indexed: 01/08/2023] Open
Abstract
Predictive assays are needed to help optimise treatment in muscle-invasive bladder cancer, where patients can be treated by either cystectomy or radical radiotherapy. Our finding that low tumour MRE11 expression is predictive of poor response to radiotherapy but not cystectomy was recently independently validated. Here we investigated further the mechanism underlying low MRE11 expression seen in poorly-responding patients. MRE11 RNA and protein levels were measured in 88 bladder tumour patient samples, by real-time PCR and immunohistochemistry respectively, and a panel of eight bladder cancer cell lines was screened for MRE11, RAD50 and NBS1 mRNA and protein expression. There was no correlation between bladder tumour MRE11 protein and RNA scores (Spearman's rho 0.064, p=0.65), suggesting MRE11 is controlled post-transcriptionally, a pattern confirmed in eight bladder cancer cell lines. In contrast, NBS1 and RAD50 mRNA and protein levels were correlated (p=0.01 and p=0.03, respectively), suggesting primary regulation at the level of transcription. MRE11 protein levels were correlated with NBS1 and RAD50 mRNA and protein levels, implicating MRN complex formation as an important determinant of MRE11 expression, driven by RAD50 and NBS1 expression. Our findings of the post-transcriptional nature of the control of MRE11 imply that any predictive assays used in patients need to be performed at the protein level rather than the mRNA level.
Collapse
Affiliation(s)
- Rebecca M Martin
- Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, UK
| | | | | | | | | | | | | | | |
Collapse
|
29
|
McPherson LA, Shen Y, Ford JM. Poly (ADP-ribose) polymerase inhibitor LT-626: Sensitivity correlates with MRE11 mutations and synergizes with platinums and irinotecan in colorectal cancer cells. Cancer Lett 2013; 343:217-23. [PMID: 24215868 DOI: 10.1016/j.canlet.2013.10.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/30/2013] [Accepted: 10/10/2013] [Indexed: 02/07/2023]
Abstract
Some colorectal cancers (CRC) display microsatellite instability (MSI) leading to mutations in genes such as MRE11. The aim of this study was to determine whether MSI or MRE11 mutational status correlates with sensitivity to the PARP inhibitor LT-626 and whether LT-626 synergizes with DNA-damaging chemotherapeutic agents. CRC cells harboring biallelic MRE11 mutations were more sensitive to LT-626 and stable overexpression or knock-down of MRE11 in cell lines correlated with sensitivity. Synergism was evident between LT-626 and cisplatin, oxaliplatin and SN-38 suggesting that PARP inhibitors in combination with DNA damaging agents may be a successful strategy for treatment of CRC.
Collapse
Affiliation(s)
- Lisa A McPherson
- Division of Oncology, Stanford University School of Medicine, Stanford, CA, United States
| | - Yuqiao Shen
- BioMarin Pharmaceutical Inc., Novato, CA, United States
| | - James M Ford
- Division of Oncology, Stanford University School of Medicine, Stanford, CA, United States.
| |
Collapse
|
30
|
Suhasini AN, Sommers JA, Muniandy PA, Coulombe Y, Cantor SB, Masson JY, Seidman MM, Brosh RM. Fanconi anemia group J helicase and MRE11 nuclease interact to facilitate the DNA damage response. Mol Cell Biol 2013; 33:2212-27. [PMID: 23530059 PMCID: PMC3648079 DOI: 10.1128/mcb.01256-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 03/14/2013] [Indexed: 01/31/2023] Open
Abstract
FANCJ mutations are linked to Fanconi anemia (FA) and increase breast cancer risk. FANCJ encodes a DNA helicase implicated in homologous recombination (HR) repair of double-strand breaks (DSBs) and interstrand cross-links (ICLs), but its mechanism of action is not well understood. Here we show with live-cell imaging that FANCJ recruitment to laser-induced DSBs but not psoralen-induced ICLs is dependent on nuclease-active MRE11. FANCJ interacts directly with MRE11 and inhibits its exonuclease activity in a specific manner, suggesting that FANCJ regulates the MRE11 nuclease to facilitate DSB processing and appropriate end resection. Cells deficient in FANCJ and MRE11 show increased ionizing radiation (IR) resistance, reduced numbers of γH2AX and RAD51 foci, and elevated numbers of DNA-dependent protein kinase catalytic subunit foci, suggesting that HR is compromised and the nonhomologous end-joining (NHEJ) pathway is elicited to help cells cope with IR-induced strand breaks. Interplay between FANCJ and MRE11 ensures a normal response to IR-induced DSBs, whereas FANCJ involvement in ICL repair is regulated by MLH1 and the FA pathway. Our findings are discussed in light of the current model for HR repair.
Collapse
Affiliation(s)
- Avvaru N. Suhasini
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, NIH Biomedical Research Center, Baltimore, Maryland, USA
| | - Joshua A. Sommers
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, NIH Biomedical Research Center, Baltimore, Maryland, USA
| | - Parameswary A. Muniandy
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, NIH Biomedical Research Center, Baltimore, Maryland, USA
| | - Yan Coulombe
- Genome Stability Laboratory, Laval University Cancer Research Center, Quebec, Canada
| | - Sharon B. Cantor
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jean-Yves Masson
- Genome Stability Laboratory, Laval University Cancer Research Center, Quebec, Canada
| | - Michael M. Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, NIH Biomedical Research Center, Baltimore, Maryland, USA
| | - Robert M. Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, NIH Biomedical Research Center, Baltimore, Maryland, USA
| |
Collapse
|
31
|
MEN1 is a melanoma tumor suppressor that preserves genomic integrity by stimulating transcription of genes that promote homologous recombination-directed DNA repair. Mol Cell Biol 2013; 33:2635-47. [PMID: 23648481 DOI: 10.1128/mcb.00167-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Multiple endocrine neoplasia type 1 is a familial cancer syndrome resulting from loss-of-function mutations in the MEN1 gene. We previously identified the tumor suppressor MEN1 as a gene required for oncogene-induced senescence in melanocytes, raising the possibility that MEN1 is a melanoma tumor suppressor. Here we show that MEN1 expression is lost in a high percentage of human melanomas and melanoma cell lines. We find that melanocytes depleted of MEN1 are deficient in homologous recombination (HR)-directed DNA repair, which is accompanied by increased nonhomologous end-joining activity. Following DNA damage, MEN1 levels increase as a result of phosphorylation by the DNA damage kinase ATM/ATR. Most importantly, we show that MEN1 functions by directly stimulating the transcription of several genes, including BRCA1, RAD51, and RAD51AP1, that encode proteins involved in HR. MEN1 and its coactivator, the mixed-lineage leukemia histone methyltransferase, are recruited to the BRCA1, RAD51, and RAD51AP1 promoters by estrogen receptor 1, resulting in increased histone H3-lysine 4 trimethylation and transcription. Collectively, our results indicate that MEN1 is a melanoma tumor suppressor that functions by stimulating the transcription of genes involved in HR-directed DNA repair.
Collapse
|
32
|
Gaymes TJ, Mohamedali AM, Patterson M, Matto N, Smith A, Kulasekararaj A, Chelliah R, Curtin N, Farzaneh F, Shall S, Mufti GJ. Microsatellite instability induced mutations in DNA repair genes CtIP and MRE11 confer hypersensitivity to poly (ADP-ribose) polymerase inhibitors in myeloid malignancies. Haematologica 2013; 98:1397-406. [PMID: 23349304 DOI: 10.3324/haematol.2012.079251] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Inactivation of the DNA mismatch repair pathway manifests as microsatellite instability, an accumulation of mutations that drives carcinogenesis. Here, we determined whether microsatellite instability in acute myeloid leukemia and myelodysplastic syndrome correlated with chromosomal instability and poly (ADP-ribose) polymerase (PARP) inhibitor sensitivity through disruption of DNA repair function. Acute myeloid leukemia cell lines (n=12) and primary cell samples (n=18), and bone marrow mononuclear cells from high-risk myelodysplastic syndrome patients (n=63) were profiled for microsatellite instability using fluorescent fragment polymerase chain reaction. PARP inhibitor sensitivity was performed using cell survival, annexin V staining and cell cycle analysis. Homologous recombination was studied using immunocytochemical analysis. SNP karyotyping was used to study chromosomal instability. RNA silencing, Western blotting and gene expression analysis was used to study the functional consequences of mutations. Acute myeloid leukemia cell lines (4 of 12, 33%) and primary samples (2 of 18, 11%) exhibited microsatellite instability with mono-allelic mutations in CtIP and MRE11. These changes were associated with reduced expression of mismatch repair pathway components, MSH2, MSH6 and MLH1. Both microsatellite instability positive primary acute myeloid leukemia samples and cell lines demonstrated a downregulation of homologous recombination DNA repair conferring marked sensitivity to PARP inhibitors. Similarly, bone marrow mononuclear cells from 11 of 56 (20%) patients with de novo high-risk myelodysplastic syndrome exhibited microsatellite instability. Significantly, all 11 patients with microsatellite instability had cytogenetic abnormalities with 4 of them (36%) possessing a mono-allelic microsatellite mutation in CtIP. Furthermore, 50% reduction in CtIP expression by RNA silencing also down-regulated homologous recombination DNA repair responses conferring PARP inhibitor sensitivity, whilst CtIP differentially regulated the expression of homologous recombination modulating RecQ helicases, WRN and BLM. In conclusion, microsatellite instability dependent mutations in DNA repair genes, CtIP and MRE11 are detected in myeloid malignancies conferring hypersensitivity to PARP inhibitors. Microsatellite instability is significantly correlated with chromosomal instability in myeloid malignancies.
Collapse
Affiliation(s)
- Terry J Gaymes
- Department of Haematological Medicine, King’s College London, Leukaemia Sciences Laboratories, The Rayne Institute, Denmark Hill Campus, London UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Oplustilova L, Wolanin K, Mistrik M, Korinkova G, Simkova D, Bouchal J, Lenobel R, Bartkova J, Lau A, O’Connor MJ, Lukas J, Bartek J. Evaluation of candidate biomarkers to predict cancer cell sensitivity or resistance to PARP-1 inhibitor treatment. Cell Cycle 2012; 11:3837-50. [PMID: 22983061 PMCID: PMC3495826 DOI: 10.4161/cc.22026] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Impaired DNA damage response pathways may create vulnerabilities of cancer cells that can be exploited therapeutically. One such selective vulnerability is the sensitivity of BRCA1- or BRCA2-defective tumors (hence defective in DNA repair by homologous recombination, HR) to inhibitors of the poly(ADP-ribose) polymerase-1 (PARP-1), an enzyme critical for repair pathways alternative to HR. While promising, treatment with PARP-1 inhibitors (PARP-1i) faces some hurdles, including (1) acquired resistance, (2) search for other sensitizing, non-BRCA1/2 cancer defects and (3) lack of biomarkers to predict response to PARP-1i. Here we addressed these issues using PARP-1i on 20 human cell lines from carcinomas of the breast, prostate, colon, pancreas and ovary. Aberrations of the Mre11-Rad50-Nbs1 (MRN) complex sensitized cancer cells to PARP-1i, while p53 status was less predictive, even in response to PARP-1i combinations with camptothecin or ionizing radiation. Furthermore, monitoring PARsylation and Rad51 foci formation as surrogate markers for PARP activity and HR, respectively, supported their candidacy for biomarkers of PARP-1i responses. As to resistance mechanisms, we confirmed the role of the multidrug resistance efflux transporters and its reversibility. More importantly, we demonstrated that shRNA lentivirus-mediated depletion of 53BP1 in human BRCA1-mutant breast cancer cells increased their resistance to PARP-1i. Given the preferential loss of 53BP1 in BRCA-defective and triple-negative breast carcinomas, our findings warrant assessment of 53BP1 among candidate predictive biomarkers of response to PARPi. Overall, this study helps characterize genetic and functional determinants of cellular responses to PARP-1i and contributes to the search for biomarkers to exploit PARP inhibitors in cancer therapy.
Collapse
Affiliation(s)
- Lenka Oplustilova
- Danish Cancer Society Research Center; Copenhagen, Denmark
- AstraZeneca; iMed Oncology; Macclesfield, Cheshire, UK
| | - Kamila Wolanin
- Danish Cancer Society Research Center; Copenhagen, Denmark
| | - Martin Mistrik
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| | - Gabriela Korinkova
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| | - Dana Simkova
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| | - Jan Bouchal
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| | - Rene Lenobel
- Laboratory of Growth Regulators; Palacky University Olomouc; Olomouc, Czech Republic
| | | | - Alan Lau
- AstraZeneca; iMed Oncology; Macclesfield, Cheshire, UK
| | | | - Jiri Lukas
- Danish Cancer Society Research Center; Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen, Denmark
| | - Jiri Bartek
- Danish Cancer Society Research Center; Copenhagen, Denmark
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| |
Collapse
|
34
|
Daemen A, Wolf DM, Korkola JE, Griffith OL, Frankum JR, Brough R, Jakkula LR, Wang NJ, Natrajan R, Reis-Filho JS, Lord CJ, Ashworth A, Spellman PT, Gray JW, van’t Veer LJ. Cross-platform pathway-based analysis identifies markers of response to the PARP inhibitor olaparib. Breast Cancer Res Treat 2012; 135:505-17. [PMID: 22875744 PMCID: PMC3429780 DOI: 10.1007/s10549-012-2188-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/25/2012] [Indexed: 12/15/2022]
Abstract
Poly(ADP-ribose) polymerase (PARP) is an enzyme involved in DNA repair. PARP inhibitors can act as chemosensitizers, or operate on the principle of synthetic lethality when used as single agent. Clinical trials have shown drugs in this class to be promising for BRCA mutation carriers. We postulated that inability to demonstrate response in non-BRCA carriers in which BRCA is inactivated by other mechanisms or with deficiency in homologous recombination for DNA repair is due to lack of molecular markers that define a responding subpopulation. We identified candidate markers for this purpose for olaparib (AstraZeneca) by measuring inhibitory effects of nine concentrations of olaparib in 22 breast cancer cell lines and identifying features in transcriptional and genome copy number profiles that were significantly correlated with response. We emphasized in this discovery process genes involved in DNA repair. We found that the cell lines that were sensitive to olaparib had a significant lower copy number of BRCA1 compared to the resistant cell lines (p value 0.012). In addition, we discovered seven genes from DNA repair pathways whose transcriptional levels were associated with response. These included five genes (BRCA1, MRE11A, NBS1, TDG, and XPA) whose transcript levels were associated with resistance and two genes (CHEK2 and MK2) whose transcript levels were associated with sensitivity. We developed an algorithm to predict response using the seven-gene transcription levels and applied it to 1,846 invasive breast cancer samples from 8 U133A/plus 2 (Affymetrix) data sets and found that 8-21 % of patients would be predicted to be responsive to olaparib. A similar response frequency was predicted in 536 samples analyzed on an Agilent platform. Importantly, tumors predicted to respond were enriched in basal subtype tumors. Our studies support clinical evaluation of the utility of our seven-gene signature as a predictor of response to olaparib.
Collapse
Affiliation(s)
- Anneleen Daemen
- Laboratory Medicine, University of California San Francisco, 2340 Sutter Street Box 0808, San Francisco, CA 94115 USA
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Denise M. Wolf
- Laboratory Medicine, University of California San Francisco, 2340 Sutter Street Box 0808, San Francisco, CA 94115 USA
| | - James E. Korkola
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Obi L. Griffith
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Jessica R. Frankum
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Rachel Brough
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Lakshmi R. Jakkula
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Nicholas J. Wang
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Rachael Natrajan
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Jorge S. Reis-Filho
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Christopher J. Lord
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Alan Ashworth
- The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB UK
| | - Paul T. Spellman
- Cancer & DNA Damage Responses, Lawrence Berkeley National Laboratories, One Cyclotron Road, Berkeley, CA 94720 USA
| | - Joe W. Gray
- Department of Biomedical Engineering, Oregon Health and Science University, 3303 SW Bond Avenue, Room #13000, Portland, OR 97239 USA
| | - Laura J. van’t Veer
- Laboratory Medicine, University of California San Francisco, 2340 Sutter Street Box 0808, San Francisco, CA 94115 USA
| |
Collapse
|
35
|
Popuri V, Ramamoorthy M, Tadokoro T, Singh DK, Karmakar P, Croteau DL, Bohr VA. Recruitment and retention dynamics of RECQL5 at DNA double strand break sites. DNA Repair (Amst) 2012; 11:624-35. [PMID: 22633600 PMCID: PMC3374033 DOI: 10.1016/j.dnarep.2012.05.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 02/04/2023]
Abstract
RECQL5 is one of the five human RecQ helicases, involved in the maintenance of genomic integrity. While much insight has been gained into the function of the Werner (WRN) and Bloom syndrome proteins (BLM), little is known about RECQL5. We have analyzed the recruitment and retention dynamics of RECQL5 at laser-induced DNA double strand breaks (DSBs) relative to other human RecQ helicases. RECQL5-depleted cells accumulate persistent 53BP1 foci followed by γ-irradiation, indicating a potential role of RECQL5 in the processing of DSBs. Real time imaging of live cells using confocal laser microscopy shows that RECQL5 is recruited early to laser-induced DSBs and remains for a shorter duration than BLM and WRN, but persist longer than RECQL4. These studies illustrate the differential involvement of RecQ helicases in the DSB repair process. Mapping of domains within RECQL5 that are necessary for recruitment to DSBs revealed that both the helicase and KIX domains are required for DNA damage recognition and stable association of RECQL5 to the DSB sites. Previous studies have shown that MRE11 is essential for the recruitment of RECQL5 to the DSB sites. Here we show that the recruitment of RECQL5 does not depend on the exonuclease activity of MRE11 or on active transcription by RNA polymerase II, one of the prominent interacting partners of RECQL5. Also, the recruitment of RECQL5 to laser-induced damage sites is independent of the presence of other DNA damage signaling and repair proteins BLM, WRN and ATM.
Collapse
Affiliation(s)
- Venkateswarlu Popuri
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224
| | | | - Takashi Tadokoro
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224
| | - Dharmendra Kumar Singh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224
| | | | - Deborah L. Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224
| | - Vilhelm A. Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224
| |
Collapse
|
36
|
Yan Z, Guo R, Paramasivam M, Shen W, Ling C, Fox D, Wang Y, Oostra AB, Kuehl J, Lee DY, Takata M, Hoatlin ME, Schindler D, Joenje H, de Winter JP, Li L, Seidman MM, Wang W. A ubiquitin-binding protein, FAAP20, links RNF8-mediated ubiquitination to the Fanconi anemia DNA repair network. Mol Cell 2012; 47:61-75. [PMID: 22705371 DOI: 10.1016/j.molcel.2012.05.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 05/01/2012] [Accepted: 05/17/2012] [Indexed: 11/29/2022]
Abstract
The Fanconi anemia (FA) protein network is necessary for repair of DNA interstrand crosslinks (ICLs), but its control mechanism remains unclear. Here we show that the network is regulated by a ubiquitin signaling cascade initiated by RNF8 and its partner, UBC13, and mediated by FAAP20, a component of the FA core complex. FAAP20 preferentially binds the ubiquitin product of RNF8-UBC13, and this ubiquitin-binding activity and RNF8-UBC13 are both required for recruitment of FAAP20 to ICLs. Both RNF8 and FAAP20 are required for recruitment of FA core complex and FANCD2 to ICLs, whereas RNF168 can modulate efficiency of the recruitment. RNF8 and FAAP20 are needed for efficient FANCD2 monoubiquitination, a key step of the FA network; RNF8 and the FA core complex work in the same pathway to promote cellular resistance to ICLs. Thus, the RNF8-FAAP20 ubiquitin cascade is critical for recruiting FA core complex to ICLs and for normal function of the FA network.
Collapse
Affiliation(s)
- Zhijiang Yan
- Laboratory of Genetics, National Institute of Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Majka J, Alford B, Ausio J, Finn RM, McMurray CT. ATP hydrolysis by RAD50 protein switches MRE11 enzyme from endonuclease to exonuclease. J Biol Chem 2011; 287:2328-41. [PMID: 22102415 DOI: 10.1074/jbc.m111.307041] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MRE11-RAD50 is a key early response protein for processing DNA ends of broken chromosomes for repair, yet how RAD50 nucleotide dynamics regulate MRE11 nuclease activity is poorly understood. We report here that ATP binding and ATP hydrolysis cause a striking butterfly-like opening and closing of the RAD50 subunits, and each structural state has a dramatic functional effect on MRE11. RAD50-MRE11 has an extended conformation in solution when MRE11 is an active nuclease. However, ATP binding to RAD50 induces a closed conformation, and in this state MRE11 is an endonuclease. ATP hydrolysis opens the RAD50-MRE11 complex, and MRE11 maintains exonuclease activity. Thus, ATP hydrolysis is a molecular switch that converts MRE11 from an endonuclease to an exonuclease. We propose a testable model in which the open-closed transitions are used by RAD50-MRE11 to discriminate among DNA ends and drive the choice of recombination pathways.
Collapse
Affiliation(s)
- Jerzy Majka
- Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, California 94720, USA
| | | | | | | | | |
Collapse
|
38
|
Sacho EJ, Maizels N. DNA repair factor MRE11/RAD50 cleaves 3'-phosphotyrosyl bonds and resects DNA to repair damage caused by topoisomerase 1 poisons. J Biol Chem 2011; 286:44945-51. [PMID: 22039049 DOI: 10.1074/jbc.m111.299347] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MRE11-RAD50 is a highly conserved multifunctional DNA repair factor. Here, we show that MRE11-RAD50 cleaves the covalent 3'-phosphotyrosyl-DNA bonds that join topoisomerase 1 (Top1) to the DNA backbone and that are the hallmark of damage caused by Top1 poisons such as camptothecin. Cleavage generates a 3'-phosphate DNA end that MRE11-RAD50 can resect in an ATP-regulated reaction, to produce a 3'-hydroxyl that can prime repair synthesis. The 3'-phosphotyrosyl cleavage activity maps to the MRE11 active site. These results define a new activity of MRE11 and distinguish MRE11-RAD50 functions in repair of Top1-DNA complexes and double-strand breaks.
Collapse
Affiliation(s)
- Elizabeth J Sacho
- Department of Immunology, University of Washington, Seattle, Washington 98195, USA
| | | |
Collapse
|
39
|
Garner KM, Eastman A. Variations in Mre11/Rad50/Nbs1 status and DNA damage-induced S-phase arrest in the cell lines of the NCI60 panel. BMC Cancer 2011; 11:206:1-13. [PMID: 21619594 PMCID: PMC3128005 DOI: 10.1186/1471-2407-11-206] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/27/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The Mre11/Rad50/Nbs1 (MRN) complex is a regulator of cell cycle checkpoints and DNA repair. Defects in MRN can lead to defective S-phase arrest when cells are damaged. Such defects may elicit sensitivity to selected drugs providing a chemical synthetic lethal interaction that could be used to target therapy to tumors with these defects. The goal of this study was to identify these defects in the NCI60 panel of cell lines and identify compounds that might elicit selective cytotoxicity. METHODS We screened the NCI60 panel in search of cell lines that express low levels of MRN proteins, or that fail to arrest in S-phase in response to the topisomerase I inhibitor SN38. The NCI COMPARE program was used to discover compounds that preferentially target cells with these phenotypes. RESULTS HCT116 cells were initially identified as defective in MRN and S phase arrest. Transfection with Mre11 also elevated Rad50 and Nbs1, and rescued the defective S-phase arrest. Cells of the NCI60 panel exhibited a large range of protein expression but a strong correlation existed between Mre11, Rad50 and Nbs1 consistent with complex formation determining protein stability. Mre11 mRNA correlated best with protein level suggesting it was the primary determinant of the overall level of the complex. Three other cell lines failed to arrest in response to SN38, two of which also had low MRN. However, other cell lines with low MRN still arrested suggesting low MRN does not predict an inability to arrest. Many compounds, including a family of benzothiazoles, correlated with the failure to arrest in S phase. The activity of benzothiazoles has been attributed to metabolic activation and DNA alkylation, but we note several cell lines in which sensitivity does not correlate with metabolism. We propose that the checkpoint defect imposes an additional mechanism of sensitivity on cells. CONCLUSIONS We have identified cells with possible defects in the MRN complex and S phase arrest, and a series of compounds that may preferentially target S phase-defective cells. We discuss limitations of the COMPARE program when attempting to identify compounds that selectively inhibit only a few cell lines.
Collapse
Affiliation(s)
- Kristen M Garner
- Department of Pharmacology and Toxicology, and Norris Cotton Cancer Center, Dartmouth Medical School, Lebanon, NH 03756, USA
| | - Alan Eastman
- Department of Pharmacology and Toxicology, and Norris Cotton Cancer Center, Dartmouth Medical School, Lebanon, NH 03756, USA
| |
Collapse
|
40
|
Gagou ME, Ganesh A, Thompson R, Phear G, Sanders C, Meuth M. Suppression of apoptosis by PIF1 helicase in human tumor cells. Cancer Res 2011; 71:4998-5008. [PMID: 21616935 DOI: 10.1158/0008-5472.can-10-4404] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Defining the processes that sustain telomere maintenance is critical to our understanding of cancer and longevity. PIF1 is a nonprocessive 5'->3' human DNA helicase that exhibits broad substrate specificity. In vitro studies have implicated PIF1 in maintaining telomeres and processing stalled DNA replication forks, but disruption of the murine Pif1 gene did not yield any apparent phenotype. In this study, we evaluated the function of the PIF1 gene in human cells by using siRNA knockdown strategies to gauge its role in the response to DNA replication stress. We found that PIF1 depletion reduced the survival of both p53-deficient and p53-proficient human tumor cells by triggering apoptosis. In contrast, nonmalignant cells were unaffected by PIF1 depletion. Apoptosis induction in tumor cells was augmented by cotreatment with replication inhibitors (thymidine, hydroxyurea, or gemcitabine). When sensitive PIF1-depleted cells were released from a thymidine-induced S-phase arrest, there remained a subpopulation of cells that failed to enter S-phase. This cell subpopulation displayed an increase in levels of cyclin E and p21, as well as a deficiency in S-phase checkpoint markers that were induced with thymidine in PIF1 expressing cells. Specifically, CHK1 activation was suppressed and we detected no consistent changes in ATM S1981 autophosphorylation, γH2AX induction, or RPA hyperphosphorylation. Death in PIF1-depleted cells was detected in late G(1)/early S-phase and was dependent on caspase-3 activity. Taken together, our findings suggest roles for PIF1 in S-phase entry and progression that are essential to protect human tumor cells from apoptosis.
Collapse
Affiliation(s)
- Mary E Gagou
- Institute for Cancer Studies, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | | | | | | | | | | |
Collapse
|
41
|
Vilar E, Bartnik CM, Stenzel SL, Raskin L, Ahn J, Moreno V, Mukherjee B, Iniesta MD, Morgan MA, Rennert G, Gruber SB. MRE11 deficiency increases sensitivity to poly(ADP-ribose) polymerase inhibition in microsatellite unstable colorectal cancers. Cancer Res 2011; 71:2632-42. [PMID: 21300766 PMCID: PMC3407272 DOI: 10.1158/0008-5472.can-10-1120] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Microsatellite instability (MSI) is displayed by approximately 15% of colorectal cancers (CRC). Defective DNA mismatch repair generates mutations at repetitive DNA sequences such as those located in the double strand break (DSB) repair gene MRE11. We assessed the mutational status of MRE11 in a panel of 17 CRC cell lines and 46 primary tumors and found a strong correlation with MSI status in both cell lines and tumors. Therefore, we hypothesized that deficiency in MRE11 may sensitize CRC cells to poly(ADP-ribose) polymerase (PARP-1) inhibition based on the concept of synthetic lethality. We further assessed the activity of the PARP-1 inhibitor, ABT-888, in CRC cell lines and observed preferential cytotoxicity in those MSI cell lines harboring mutations in MRE11 compared with both wild-type cell lines and microsatellite stable (MSS) cell lines. A significant correlation between MRE11 expression levels and cytotoxicity to ABT-888 at 10 μM was observed (R² = 0.915, P < 0.001). Using two experimental approaches, including short hairpin RNA knocking down MRE11 in the wild-type and MSS cell line SW-480 and a second cell line model transfected with mutant MRE11, we experimentally tried to confirm the role of MRE11 in conferring sensitivity to PARP-1 inhibition. Both models led to changes in proliferation in response to ABT-888 at different concentrations, and a drug-response effect was not observed, suggesting a possible contribution of additional genes. We conclude that MSI colorectal tumors deficient in DSB repair secondary to mutation in MRE11 show a higher sensitivity to PARP-1 inhibition. Further clinical investigation of PARP-1 inhibitors is warranted in MSI CRCs.
Collapse
Affiliation(s)
- Eduardo Vilar
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Catherine M. Bartnik
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Stephanie L. Stenzel
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Leon Raskin
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jaeil Ahn
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Victor Moreno
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan
- Biostatistics and Bioinformatics Unit, IDIBELL-Catalan Institute of Oncology and University of Barcelona, Barcelona, Spain
| | - Bhramar Mukherjee
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Maria D. Iniesta
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Meredith A. Morgan
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Gad Rennert
- Clalit Health Services, National Cancer Control Center and Department of Community Medicine and Epidemiology, Carmel Medical Center and B. Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Stephen B. Gruber
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan
| |
Collapse
|
42
|
Human T-lymphotropic type 1 virus p30 inhibits homologous recombination and favors unfaithful DNA repair. Blood 2011; 117:5897-906. [PMID: 21427292 DOI: 10.1182/blood-2010-08-304600] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Whereas oncogenic retroviruses are common in animals, human T-lymphotropic virus 1 (HTLV-1) is the only transmissible retrovirus associated with cancer in humans and is etiologically linked to adult T-cell leukemia. The leukemogenesis process is still largely unknown, but relies on extended survival and clonal expansion of infected cells, which in turn accumulate genetic defects. A common feature of human tumor viruses is their ability to stimulate proliferation and survival of infected pretumoral cells and then hide by establishing latency in cells that have acquired a transformed phenotype. Whereas disruption of the DNA repair is one of the major processes responsible for the accumulation of genomic abnormalities and carcinogenesis, the absence of DNA repair also poses the threat of cell-cycle arrest or apoptosis of virus-infected cells. This study describes how the HTLV-1 p30 viral protein inhibits conservative homologous recombination (HR) DNA repair by targeting the MRE11/RAD50/NBS1 complex and favors the error-prone nonhomologous-end-joining (NHEJ) DNA-repair pathway instead. As a result, HTLV-1 p30 may facilitate the accumulation of mutations in the host genome and the cumulative risk of transformation. Our results provide new insights into how human tumor viruses may manipulate cellular DNA-damage responses to promote cancer.
Collapse
|
43
|
Turner NC, Ashworth A. Biomarkers of PARP inhibitor sensitivity. Breast Cancer Res Treat 2011; 127:283-6. [DOI: 10.1007/s10549-011-1375-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/23/2011] [Indexed: 12/20/2022]
|
44
|
Martin LM, Marples B, Coffey M, Lawler M, Lynch TH, Hollywood D, Marignol L. DNA mismatch repair and the DNA damage response to ionizing radiation: Making sense of apparently conflicting data. Cancer Treat Rev 2010; 36:518-27. [PMID: 20413225 DOI: 10.1016/j.ctrv.2010.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 03/12/2010] [Accepted: 03/21/2010] [Indexed: 10/19/2022]
|
45
|
Shi W, Feng Z, Zhang J, Gonzalez-Suarez I, Vanderwaal RP, Wu X, Powell SN, Roti Roti JL, Gonzalo S, Zhang J. The role of RPA2 phosphorylation in homologous recombination in response to replication arrest. Carcinogenesis 2010; 31:994-1002. [PMID: 20130019 DOI: 10.1093/carcin/bgq035] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Failure to reactivate stalled or collapsed DNA replication forks is a potential source of genomic instability. Homologous recombination (HR) is a major mechanism for repairing the DNA damage resulting from replication arrest. The single-strand DNA (ssDNA)-binding protein, replication protein A (RPA), plays a major role in multiple processes of DNA metabolism. However, the role of RPA2 hyperphosphorylation, which occurs in response to DNA damage, had been unclear. Here, we show that hyperphosphorylated RPA2 associates with ssDNA and recombinase protein Rad51 in response to replication arrest by hydroxyurea (HU) treatment. In addition, RPA2 hyperphosphorylation is critical for Rad51 recruitment and HR-mediated repair following HU. However, RPA2 hyperphosphorylation is not essential for both ionizing radiation (IR)-induced Rad51 foci formation and I-Sce-I endonuclease-stimulated HR. Moreover, we show that expression of a phosphorylation-deficient mutant of RPA2 leads to increased chromosomal aberrations following HU treatment but not after exposure to IR. Finally, we demonstrate that loss of RPA2 hyperphosphorylation results in a loss of viability when cells are confronted with replication stress whereas cells expressing hyperphosphorylation-defective RPA2 or wild-type RPA2 have a similar sensitivity to IR. Thus, our data suggest that RPA2 hyperphosphorylation plays a critical role in maintenance of genomic stability and cell survival after a DNA replication block via promotion of HR.
Collapse
Affiliation(s)
- Wei Shi
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO 63108, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Pires IM, Ward TH, Dive C. Oxaliplatin responses in colorectal cancer cells are modulated by CHK2 kinase inhibitors. Br J Pharmacol 2010; 159:1326-38. [PMID: 20128802 DOI: 10.1111/j.1476-5381.2009.00607.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Checkpoint kinase 2 (CHK2) is activated by DNA damage and can contribute to p53 stabilization, modulating growth arrest and/or apoptosis. We investigated the contribution of CHK2 to oxaliplatin-mediated toxicity in a colorectal cancer model. EXPERIMENTAL APPROACH We evaluated the ability of CHK2 small molecule inhibitors to potentiate oxaliplatin-induced toxicity. The role of CHK2 in oxaliplatin-induced apoptosis was investigated in HCT116 cells that were wild-type (WT) or KO for CHK2. Small molecule inhibitors of CHK2 were used in combination studies with oxaliplatin in this cell model. KEY RESULTS In oxaliplatin-treated CHK2 KO cells, accelerated apoptosis was accompanied by attenuated p53 stabilization and p21(WAF-1) up-regulation correlating with increased Bax expression, cytochrome c release and elevated caspase activity. The higher levels of apoptosis in CHK2 KO cells were restored to control (WT) levels when CHK2 was re-introduced. This 'uncoupling' of p53 stabilization and Bax up-regulation in CHK2 KO cells suggested oxaliplatin-induced apoptosis was due to a p53-independent response. Combination studies revealed that CHK2 inhibitor II or debromohymenialdisine antagonized the responses to oxaliplatin. This inhibitory effect correlated with decreases in apoptosis, p53 stabilization and DNA inter-strand cross-link formation, and was dependent on the presence (but not activity) of CHK2. CONCLUSIONS AND IMPLICATIONS Combinations of CHK2 inhibitors with oxaliplatin should further sensitize cells to oxaliplatin treatment. However, these inhibitors produced an antagonistic effect on the response to oxaliplatin, which was reversed on the re-introduction of CHK2. These observations may have implications for the use of oxaliplatin in colorectal cancer therapy in combination with therapies targeting CHK2.
Collapse
Affiliation(s)
- I M Pires
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester, Manchester, UK
| | | | | |
Collapse
|
47
|
Gagou ME, Zuazua-Villar P, Meuth M. Enhanced H2AX phosphorylation, DNA replication fork arrest, and cell death in the absence of Chk1. Mol Biol Cell 2010; 21:739-52. [PMID: 20053681 PMCID: PMC2828961 DOI: 10.1091/mbc.e09-07-0618] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
H2AX phosphorylation at serine 139 (gammaH2AX) is a sensitive indicator of both DNA damage and DNA replication stress. Here we show that gammaH2AX formation is greatly enhanced in response to replication inhibitors but not ionizing radiation in HCT116 or SW480 cells depleted of Chk1. Although H2AX phosphorylation precedes the induction of apoptosis in such cells, our results suggest that cells containing gammaH2AX are not committed to death. gammaH2AX foci in these cells largely colocalize with RPA foci and their formation is dependent upon the essential replication helicase cofactor Cdc45, suggesting that H2AX phosphorylation occurs at sites of stalled forks. However Chk1-depleted cells released from replication inhibitors retain gammaH2AX foci and do not appear to resume replicative DNA synthesis. BrdU incorporation only occurs in a minority of Chk1-depleted cells containing gammaH2AX foci after release from thymidine arrest and, in cells incorporating BrdU, DNA synthesis does not occur at sites of gammaH2AX foci. Furthermore activated ATM and Chk2 persist in these cells. We propose that the gammaH2AX foci in Chk1-depleted cells may represent sites of persistent replication fork damage or abandonment that are unable to resume DNA synthesis but do not play a direct role in the Chk1 suppressed death pathway.
Collapse
Affiliation(s)
- Mary E Gagou
- Institute for Cancer Studies, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | | | | |
Collapse
|
48
|
Rajagopalan S, Sade RS, Townsley FM, Fersht AR. Mechanistic differences in the transcriptional activation of p53 by 14-3-3 isoforms. Nucleic Acids Res 2009; 38:893-906. [PMID: 19933256 PMCID: PMC2817464 DOI: 10.1093/nar/gkp1041] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
p53 maintains genome integrity by initiating the transcription of genes involved in cell-cycle arrest, senescence, apoptosis and DNA repair. The activity of p53 is regulated by both post-translational modifications and protein–protein interactions. p53 that has been phosphorylated at S366, S378 and T387 binds 14-3-3 proteins in vitro. Here, we show that these sites are potential 14-3-3 binding sites in vivo. Epsilon (ε) and gamma (γ) isoforms required phosphorylation at either of these sites for efficient interaction with p53, while for sigma (σ) and tau (τ) these sites are dispensable. Further, σ and τ bound more weakly to p53 C-terminal phosphopeptides than did ε and γ. However, the four isoforms bound tightly to di-phosphorylated p53 C-terminal peptides than did the mono-phosphorylated counterparts. Interestingly, all the isoforms studied transcriptionally activated wild-type p53. σ and τ stabilized p53 levels in cells, while ε and γ stimulated p53-DNA binding activity in vitro. Overall, the results suggest that structurally and functionally similar 14-3-3 isoforms may exert their regulatory potential on p53 through different mechanisms. We discuss the isoform-specific roles of 14-3-3 in p53 stabilization and activation of specific-DNA binding.
Collapse
|
49
|
Woerner SM, Yuan YP, Benner A, Korff S, von Knebel Doeberitz M, Bork P. SelTarbase, a database of human mononucleotide-microsatellite mutations and their potential impact to tumorigenesis and immunology. Nucleic Acids Res 2009; 38:D682-9. [PMID: 19820113 PMCID: PMC2808963 DOI: 10.1093/nar/gkp839] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
About 15% of human colorectal cancers and, at varying degrees, other tumor entities as well as nearly all tumors related to Lynch syndrome are hallmarked by microsatellite instability (MSI) as a result of a defective mismatch repair system. The functional impact of resulting mutations depends on their genomic localization. Alterations within coding mononucleotide repeat tracts (MNRs) can lead to protein truncation and formation of neopeptides, whereas alterations within untranslated MNRs can alter transcription level or transcript stability. These mutations may provide selective advantage or disadvantage to affected cells. They may further concern the biology of microsatellite unstable cells, e.g. by generating immunogenic peptides induced by frameshifts mutations. The Selective Targets database (http://www.seltarbase.org) is a curated database of a growing number of public MNR mutation data in microsatellite unstable human tumors. Regression calculations for various MSI–H tumor entities indicating statistically deviant mutation frequencies predict TGFBR2, BAX, ACVR2A and others that are shown or highly suspected to be involved in MSI tumorigenesis. Many useful tools for further analyzing genomic DNA, derived wild-type and mutated cDNAs and peptides are integrated. A comprehensive database of all human coding, untranslated, non-coding RNA- and intronic MNRs (MNR_ensembl) is also included. Herewith, SelTarbase presents as a plenty instrument for MSI-carcinogenesis-related research, diagnostics and therapy.
Collapse
Affiliation(s)
- Stefan M Woerner
- Medical Faculty of Mannheim, Institute for Clinical Chemistry, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany.
| | | | | | | | | | | |
Collapse
|
50
|
Woerner SM, Yuan YP, Benner A, Korff S, von Knebel Doeberitz M, Bork P. SelTarbase, a database of human mononucleotide-microsatellite mutations and their potential impact to tumorigenesis and immunology. Nucleic Acids Res 2009. [PMID: 19820113 DOI: 10.1093/nar/gkp839gkp839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
About 15% of human colorectal cancers and, at varying degrees, other tumor entities as well as nearly all tumors related to Lynch syndrome are hallmarked by microsatellite instability (MSI) as a result of a defective mismatch repair system. The functional impact of resulting mutations depends on their genomic localization. Alterations within coding mononucleotide repeat tracts (MNRs) can lead to protein truncation and formation of neopeptides, whereas alterations within untranslated MNRs can alter transcription level or transcript stability. These mutations may provide selective advantage or disadvantage to affected cells. They may further concern the biology of microsatellite unstable cells, e.g. by generating immunogenic peptides induced by frameshifts mutations. The Selective Targets database (http://www.seltarbase.org) is a curated database of a growing number of public MNR mutation data in microsatellite unstable human tumors. Regression calculations for various MSI-H tumor entities indicating statistically deviant mutation frequencies predict TGFBR2, BAX, ACVR2A and others that are shown or highly suspected to be involved in MSI tumorigenesis. Many useful tools for further analyzing genomic DNA, derived wild-type and mutated cDNAs and peptides are integrated. A comprehensive database of all human coding, untranslated, non-coding RNA- and intronic MNRs (MNR_ensembl) is also included. Herewith, SelTarbase presents as a plenty instrument for MSI-carcinogenesis-related research, diagnostics and therapy.
Collapse
Affiliation(s)
- Stefan M Woerner
- Medical Faculty of Mannheim, Institute for Clinical Chemistry, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany.
| | | | | | | | | | | |
Collapse
|