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Mao C, Li S, Che J, Liu D, Mao X, Rao H. The ubiquitin ligase UBR4 and the deubiquitylase USP5 modulate the stability of DNA mismatch repair protein MLH1. J Biol Chem 2024:107592. [PMID: 39032648 DOI: 10.1016/j.jbc.2024.107592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 06/29/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
MLH1 plays a critical role in DNA mismatch repair and genome maintenance. MLH1 deficiency promotes cancer development and progression, but the mechanism underlying MLH1 regulation remains enigmatic. In this study, we demonstrate that MLH1 protein is degraded by the ubiquitin-proteasome system and have identified vital cis-elements and trans-factors involved in MLH1 turnover. We found that the region encompassing the amino acids 516-650 is crucial for MLH1 degradation. The mismatch repair protein PMS2 may shield MLH1 from degradation as it bind to the MLH1 segment key to its turnover. Furthermore, we have identified the E3 ubiquitin ligase UBR4 and the deubiquitylase USP5, which oppositely modulate MLH1 stability. In consistence, UBR4 or USP5 deficiency affects the cellular response to nucleotide analog 6-TG, supporting their roles in regulating mismatch repair. Our study has revealed important insights into the regulatory mechanisms underlying MLH1 proteolysis, critical to DNA mismatch repair related diseases.
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Affiliation(s)
- Chenyu Mao
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China, 518055
| | - Siqi Li
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China, 518055
| | - Jun Che
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China, 518055
| | - Dongzhou Liu
- Department of Rheumatology and Immunology, Shenzhen People's Hospital; The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong, China, 518055
| | - Xinliang Mao
- Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong, China, 511436.
| | - Hai Rao
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China, 518055; Key University Laboratory of Metabolism and Health of Guangdong, Southern University of Science and Technology, Shenzhen, China, 518055.
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2
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Spinos T, Zografos E, Koutsoukos K, Zagouri F, Kosmas C, Driva TS, Goutas D, Gakiopoulou C, Agrogiannis G, Theochari E, Tzavara C, Lazaris AC. Predictive tissue markers in testicular germ cell tumors: Immunohistochemical expression of MLH1 and REV-7 proteins. Int Urol Nephrol 2024; 56:1887-1898. [PMID: 38285100 PMCID: PMC11090952 DOI: 10.1007/s11255-023-03933-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 12/27/2023] [Indexed: 01/30/2024]
Abstract
PURPOSE Testicular Germ Cell Tumors (TGCTs) are the most frequent solid malignancies in young adult men. Regardless of differences in their cell of origin, all TGCTs are considered highly curable malignancies. However, approximately 3-5% of all TGCTs do not respond to platinum-based chemotherapies. The purpose of our paper is to investigate whether immunohistochemical expression of MLH1 and REV-7 can be used as predictive tissue markers for TGCTs. MATERIAL AND METHODS The main demographic and clinicopathological characteristics of 64 male patients with TGCTs who underwent orchiectomy from 2007 to 2022 were retrospectively obtained from two large Oncology Clinics in Greece. Both patients with chemosensitive and chemoresistant disease were included. Immunohistochemical staining for MLH1 and REV-7 proteins was applied in specimens of these patients. RESULTS 31 seminomas and 33 non-seminomas were included. 48 patients had chemosensitive disease, while 16 had chemoresistant disease. 53 specimens showed preserved MLH1 expression, while 11 specimens had lost MLH1 expression. Expression of MLH1 was only significantly associated with patients' age. 16 specimens showed positive REV-7 expression, while 48 specimens were REV-7 negative. Interestingly, 50% of patients with chemoresistant disease and 16,7% of patients with chemosensitive disease were REV-7 positive. This difference was statistically significant. Moreover, REV-7 positivity was significantly associated with chemoresistance, various clinicopathological parameters and patients' prognosis and survival. CONCLUSION Loss of MLH1 expression was only found to be significantly associated with lower patients' age. Positive immunohistochemical REV-7 expression was significantly associated with various clinicopathological parameters, while it was also associated with significantly lower survival and greater hazard. REV-7 positive percentages were significantly higher in patients with chemoresistant disease. Our findings imply that immunohistochemical staining for REV-7 could potentially be used as a predictive tissue marker for TGCT tumors. Moreover, targeting of REV-7 protein, could represent a potential therapeutic strategy for chemoresistant TGCT cases. The implementation of well-designed studies on a larger scale is of utmost importance, in order to draw safer conclusions. Additional studies are needed so as to draw safer conclusions.
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Affiliation(s)
- Theodoros Spinos
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece.
| | - Eleni Zografos
- Oncology Unit, Department of Clinical Therapeutics, National and Apodistrian University of Athens, Alexandra Hospital, Athens, Greece
| | - Konstantinos Koutsoukos
- Oncology Unit, Department of Clinical Therapeutics, National and Apodistrian University of Athens, Alexandra Hospital, Athens, Greece
| | - Flora Zagouri
- Oncology Unit, Department of Clinical Therapeutics, National and Apodistrian University of Athens, Alexandra Hospital, Athens, Greece
| | - Christos Kosmas
- Department of Medical Oncology, Hematopoietic Cell Transplant Unit, Metaxa Memorial Cancer Hospital, Piraeus, Greece
| | - Tatiana S Driva
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
| | - Dimitrios Goutas
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
| | - Charikleia Gakiopoulou
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
| | - George Agrogiannis
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
| | - Eirini Theochari
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
| | - Chara Tzavara
- Department of Biostatistics, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Andreas C Lazaris
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias Str., 115 27, Goudi, Athens, Greece
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Vasilopoulos SN, Güner H, Uça Apaydın M, Pavlopoulou A, Georgakilas AG. Dual Targeting of DNA Damage Response Proteins Implicated in Cancer Radioresistance. Genes (Basel) 2023; 14:2227. [PMID: 38137049 PMCID: PMC10742610 DOI: 10.3390/genes14122227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/13/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023] Open
Abstract
Ionizing radiation can induce different types of DNA lesions, leading to genomic instability and ultimately cell death. Radiation therapy or radiotherapy, a major modality in cancer treatment, harnesses the genotoxic potential of radiation to target and destroy cancer cells. Nevertheless, cancer cells have the capacity to develop resistance to radiation treatment (radioresistance), which poses a major obstacle in the effective management of cancer. It has been shown that administration of platinum-based drugs to cancer patients can increase tumor radiosensitivity, but despite this, it is associated with severe adverse effects. Several lines of evidence support that activation of the DNA damage response and repair machinery in the irradiated cancer cells enhances radioresistance and cellular survival through the efficient repair of DNA lesions. Therefore, targeting of key DNA damage repair factors would render cancer cells vulnerable to the irradiation effects, increase cancer cell killing, and reduce the risk of side effects on healthy tissue. Herein, we have employed a computer-aided drug design approach for generating ab initio a chemical compound with drug-like properties potentially targeting two proteins implicated in multiple DNA repair pathways. The findings of this study could be taken into consideration in clinical decision-making in terms of co-administering radiation with DNA damage repair factor-based drugs.
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Affiliation(s)
- Spyridon N. Vasilopoulos
- DNA Damage Laboratory, Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou Campus, 15780 Athens, Greece;
- Department of Science and Mathematics, Deree-The American College of Greece, 6 Gravias Street, 15342 Athens, Greece
| | - Hüseyin Güner
- Izmir Biomedicine and Genome Center (IBG), 35340 Izmir, Turkey; (H.G.); (M.U.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, 35340 Izmir, Turkey
- Department of Molecular Biology and Genetics, Faculty of Life and Natural Science, Abdullah Gül University, 38080 Kayseri, Turkey
| | - Merve Uça Apaydın
- Izmir Biomedicine and Genome Center (IBG), 35340 Izmir, Turkey; (H.G.); (M.U.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, 35340 Izmir, Turkey
| | - Athanasia Pavlopoulou
- Izmir Biomedicine and Genome Center (IBG), 35340 Izmir, Turkey; (H.G.); (M.U.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, 35340 Izmir, Turkey
| | - Alexandros G. Georgakilas
- DNA Damage Laboratory, Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou Campus, 15780 Athens, Greece;
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4
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Sfakianaki M, Tzardi M, Tsantaki K, Koutoulaki C, Messaritakis I, Datseri G, Moustou E, Mavroudis D, Souglakos J. Evaluation of Microsatellite Instability Molecular Analysis versus Immuno-Histochemical Interpretation in Malignant Neoplasms with Different Localizations. Cancers (Basel) 2023; 15:cancers15020353. [PMID: 36672302 PMCID: PMC9856558 DOI: 10.3390/cancers15020353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/09/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
MMR gene germline mutations are considered a major genetic disorder in patients with hereditary nonpolyposis colon cancer (HNPCC) or Lynch syndrome; A total of 15% of sporadic colon carcinomas are MSI-High. MSI has also been observed in other cancers, such as endometrial, gastric, and ovarian cancer. The aim of the current study was to correlate and outline the optimal method between the molecular testing of the instability of microsatellite DNA regions (MSI status) and the loss of protein expression by immunehistochemistry (MMR). A total of 242 paraffin-embedded tissues from gastrointestinal, gynecological, genitourinary, lung, breast, and unknown primary cancer patients were analyzed for the expression of MLH1/MSH2/MSH6/PMS2 by immunohistochemistry, as well as for the molecular analysis of MSI status using PCR-based molecular fragment analysis. A total of 29 MSI-High patients were detected molecularly, while 23 patients were detected by immunohistochemistry, with rates that are comparable according to the literature. Based on the agreement coefficient of the two methods, a substantial agreement emerged (Kappa = 0.675 with standard error = 0.081, p < 0.001). Despite the substantial agreement, both methods ought to be established to determine MSI-H/dMMR status in all cancer types as a first-line screening test.
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Affiliation(s)
- Maria Sfakianaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
- Correspondence: (M.S.); (I.M.); Tel.: +30-281-039-4926 (I.M.)
| | - Maria Tzardi
- Department of Pathology, University General Hospital of Heraklion, 71110 Heraklion, Greece
| | - Konstantina Tsantaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Chara Koutoulaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Ippokratis Messaritakis
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
- Correspondence: (M.S.); (I.M.); Tel.: +30-281-039-4926 (I.M.)
| | - Galateia Datseri
- Department of Pathology, University General Hospital of Heraklion, 71110 Heraklion, Greece
| | - Eleni Moustou
- Department of Pathology, University General Hospital of Heraklion, 71110 Heraklion, Greece
| | - Dimitrios Mavroudis
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
- Department of Medical Oncology, University General Hospital of Heraklion, 71500 Iraklio, Greece
| | - John Souglakos
- Laboratory of Translational Oncology, School of Medicine, University of Crete, 71003 Heraklion, Greece
- Department of Medical Oncology, University General Hospital of Heraklion, 71500 Iraklio, Greece
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5
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Mahdouani M, Ben Ahmed S, Hmila F, Rais H, Ben Sghaier R, Saad H, Ben Said M, Masmoudi S, Hmida D, Brieger A, Zeuzem S, Saad A, Gribaa M, Plotz G. Functional characterization of MLH1 missense variants unveils mechanisms of pathogenicity and clarifies role in cancer. PLoS One 2022; 17:e0278283. [PMID: 36454741 PMCID: PMC9714755 DOI: 10.1371/journal.pone.0278283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/28/2022] [Indexed: 12/05/2022] Open
Abstract
Lynch syndrome is a heritable condition caused by a heterozygous germline inactivating mutation of the DNA mismatch repair (MMR) genes, most commonly the MLH1 gene. However, one third of the identified alterations are missense variants, for which the clinical significance is unclear in many cases. We have identified three MLH1 missense alterations (p.(Glu736Lys), p.(Pro640Thr) and p.(Leu73Pro)) in six individuals from large Tunisian families. For none of these alterations, a classification of pathogenicity was available, consequently diagnosis, predictive testing and targeted surveillance in affected families was impossible. We therefore performed functional laboratory testing using a system testing stability as well as catalytic activity that includes clinically validated reference variants. Both p.(Leu73Pro) and p.(Pro640Thr) were found to be non-functional due to severe defects in protein stability and catalytic activity. In contrast, p.(Glu736Lys) was comparable to the wildtype protein and therefore considered a neutral substitution. Analysis of residue conservation and of the structural roles of the substituted residues corroborated these findings. In conjunction with the available clinical data, two variants fulfil classification criteria for class 4 "likely pathogenic". The findings of this work clarify the mechanism of pathogenicity of two unclear MLH1 variants and enables predictive testing and targeted surveillance in members of carrier families worldwide.
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Affiliation(s)
- Marwa Mahdouani
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Slim Ben Ahmed
- Department of Oncology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Fahmi Hmila
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
- Department of General and Digestive Surgery, Farhat Hached University Hospital, Sousse, Tunisia
| | - Henda Rais
- Medical Service, Salah Azaiez Institute, Tunis, Tunisia
| | - Rihab Ben Sghaier
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Hanene Saad
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, Sfax, Tunisia
| | - Dorra Hmida
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Angela Brieger
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
| | - Stefan Zeuzem
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
| | - Ali Saad
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Moez Gribaa
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Guido Plotz
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
- * E-mail:
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6
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Huang Y, Feng L, Bao Y, Zhang Y, Liang J, Mao Q, Li J, Jiang C. Expressing MLH1 in HCT116 cells increases cellular resistance to radiation by activating the PRKAC. Exp Biol Med (Maywood) 2021; 247:426-432. [PMID: 34787019 DOI: 10.1177/15353702211059829] [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] [Indexed: 11/17/2022] Open
Abstract
Mut L homolog-1 (MLH1) is a key DNA mismatch repair protein which participates in the sensitivity to DNA damaging agents. However, its role in the radiosensitivity of tumor cells is less well characterized. In this study, we investigated the role of MLH1 in cellular responses to ionizing radiation (IR) and explored the signaling molecules involved. The isogenic pair of MLH1 proficient (MLH1+) and deficient (MLH1-) human colorectal cancer HCT116 cells was exposed to IR for 24 h at the dose of 3 cGy. The clonogenic survival was examined by the colony formation assay. Cell cycle distribution was analyzed with flow cytometry. Changes in the protein level of MLH1, DNA damage marker γH2AX, and protein kinase A catalytic subunit (PRKAC), a common target for anti-tumor drugs, were examined with Western blotting. The results showed that the HCT116 (MLH1+) cells demonstrated increased radio-resistance with increased S population, decreased G2 population, a low level of γH2AX, a reduced ratio of phosphorylated PRKACαβ to total PRKAC, and an elevated level of total PRKAC and phosphorylated PRKACβII following IR compared with the HCT116 (MLH1-) cells. Importantly, silencing PRKAC in HCT116 (MLH1+) cells increased the cellular radiosensitivity. In conclusion, MLH1 may increase cellular resistance to IR by activating PRKAC. Our finding is the first to demonstrate the important role of PRKAC in MLH1-mediated radiosensitivity, suggesting that PRKAC has potential as a biomarker and a therapeutic target for increasing radio-sensitization.
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Affiliation(s)
- Yuling Huang
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Liu Feng
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Yongqiang Bao
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Yun Zhang
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Jinghui Liang
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Qingfeng Mao
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China
| | - Jingao Li
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China.,Key Laboratory of Personalized Diagnosis and Treatment of Nasopharyngeal Carcinoma, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China.,Medical College of Nanchang University, Nanchang University, Nanchang, Jiangxi, 330031, China
| | - Chunling Jiang
- Department of Radiation Oncology, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China.,Key Laboratory of Personalized Diagnosis and Treatment of Nasopharyngeal Carcinoma, Jiangxi Cancer Hospital of Nanchang University, Nanchang, Jiangxi 330029, China.,Medical College of Nanchang University, Nanchang University, Nanchang, Jiangxi, 330031, China
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7
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Pajkos M, Zeke A, Dosztányi Z. Ancient Evolutionary Origin of Intrinsically Disordered Cancer Risk Regions. Biomolecules 2020; 10:biom10081115. [PMID: 32731489 PMCID: PMC7465906 DOI: 10.3390/biom10081115] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Cancer is a heterogeneous genetic disease that alters the proper functioning of proteins involved in key regulatory processes such as cell cycle, DNA repair, survival, or apoptosis. Mutations often accumulate in hot-spots regions, highlighting critical functional modules within these proteins that need to be altered, amplified, or abolished for tumor formation. Recent evidence suggests that these mutational hotspots can correspond not only to globular domains, but also to intrinsically disordered regions (IDRs), which play a significant role in a subset of cancer types. IDRs have distinct functional properties that originate from their inherent flexibility. Generally, they correspond to more recent evolutionary inventions and show larger sequence variations across species. In this work, we analyzed the evolutionary origin of disordered regions that are specifically targeted in cancer. Surprisingly, the majority of these disordered cancer risk regions showed remarkable conservation with ancient evolutionary origin, stemming from the earliest multicellular animals or even beyond. Nevertheless, we encountered several examples where the mutated region emerged at a later stage compared with the origin of the gene family. We also showed the cancer risk regions become quickly fixated after their emergence, but evolution continues to tinker with their genes with novel regulatory elements introduced even at the level of humans. Our concise analysis provides a much clearer picture of the emergence of key regulatory elements in proteins and highlights the importance of taking into account the modular organisation of proteins for the analyses of evolutionary origin.
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Affiliation(s)
- Mátyás Pajkos
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter stny 1/c, H-1117 Budapest, Hungary;
| | - András Zeke
- Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary;
| | - Zsuzsanna Dosztányi
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter stny 1/c, H-1117 Budapest, Hungary;
- Correspondence:
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8
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Ben Sghaier R, Jansen AML, Bdioui A, Van Wezel T, Ksiaa M, Elgolli L, Ben Fatma L, Ben Ahmed S, Azzouz MM, Hellara O, Elghali A, Darbel F, Skandrani K, Mokkni M, Gdissa A, Ltaief R, Saad A, Hmila F, Gribaa M, Morreau H. Targeted next generation sequencing screening of Lynch syndrome in Tunisian population. Fam Cancer 2019; 18:343-348. [PMID: 31114938 DOI: 10.1007/s10689-019-00130-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A high colorectal cancer (CRC) incidence is observed in Tunisia, with a relatively high proportion of patients developing CRC before the age of 40. While this suggests a genetic susceptibility, only a few Tunisian Lynch Syndrome families have been described. In this study we aimed to identify the underlying genetic cause in 32 patients with early onset CRC and/or a positive family history. Of twenty-four patients' tumor or biopsies could be analyzed with immunohistochemical staining to detect loss of expression of one of the MMR proteins. Ten tumors showed loss of expression, of which one tumor was from a patient where a germline pathogenic MSH2 variant was detected previously with Sanger sequencing. Next generation sequencing of the MMR, POLE and POLD1 genes was performed in leukocyte and tumor DNA of the remaining nine patients, as well as in two patients with MMR-proficient tumors, but with severe family history. In six of 11 patients a germline variant was detected in MLH1 (n = 5) or MSH2 (n = 1). Two of six patients were from the same family and both were found to carry a novel in-frame MLH1 deletion, predicted to affect MLH1 function. All MLH1 variant carriers had loss of heterozygosity with retention of the variant in the tumors, while a somatic pathogenic variant was detected in the patient with the germline MSH2 variant.
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Affiliation(s)
- Rihab Ben Sghaier
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia.
| | | | - Ahlem Bdioui
- Cytology and Anatomopathology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Tom Van Wezel
- Pathology Department, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Mehdi Ksiaa
- Gastroenterology Department, Sahloul Hospital, Sousse, Tunisia
| | | | - Leila Ben Fatma
- Carcinology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Slim Ben Ahmed
- Carcinology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | | | - Olfa Hellara
- Gastroenterology Department, Fatouma Bourguiba Hospital, Monastir, Tunisia
| | - Amine Elghali
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | | | | | - Moncef Mokkni
- Cytology and Anatomopathology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Ameni Gdissa
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Rached Ltaief
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Ali Saad
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Fahmi Hmila
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Moez Gribaa
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Hans Morreau
- Pathology Department, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
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9
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Sundaram MK, Unni S, Somvanshi P, Bhardwaj T, Mandal RK, Hussain A, Haque S. Genistein Modulates Signaling Pathways and Targets Several Epigenetic Markers in HeLa Cells. Genes (Basel) 2019; 10:E955. [PMID: 31766427 PMCID: PMC6947182 DOI: 10.3390/genes10120955] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Several epigenetic changes are responsible for transcriptional alterations of signaling pathways and tumour suppressor genes (TSGs) contributing to carcinogenesis. This study was aimed to examine the effect of the phytochemical, genistein on various molecular targets in HeLa cells. METHODS Quantitative PCR was used to analyze the expression of various molecular targets. Biochemical assays were employed to study the epigenetic enzymes. To correlate the transcriptional status of the selected TSGs and epigenetic modulation, their promoter 5'CpG methylation levels were evaluated by quantitative methylation array followed by methylation specific restriction digestion. RESULTS The expression of several genes involved in the cell cycle regulation, migration, inflammation, phosphatidylinositol 3-kinase (PI3K) and mitogen activated kinase-like protein (MAPK) pathway were found to be modulated including CCNB1, TWIST1, MMP14, TERT, AKT1, PTPRR, FOS and IL1A. Genistein modulated the expression of DNA methyltransferases (DNMTs), histone deacetylases (HDACs), histone methyltransferases (HMTs), demethylases, and histone phosphorylases. Furthermore, genistein decreased the activity of DNMTs, HDACs, and HMTs and reduced global DNA methylation levels. Promoter methylation of several TSGs, including FHIT, RUNX3, CDH1, PTEN, and SOC51, was lowered with corresponding transcriptional increase. Network analysis indicated similar effect of genistein. CONCLUSION This study presents a comprehensive mechanism of action of genistein showcasing effective epigenetic modulation and widespread transcriptional changes resulting in restoration of tumour suppressor gene expression. This study corroborates the development of genistein as a candidate for anti-cancer therapy.
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Affiliation(s)
| | - Sreepoorna Unni
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, P.O. Box 19282 Dubai, UAE;
| | - Pallavi Somvanshi
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi-110070, India; (P.S.); (T.B.)
| | - Tulika Bhardwaj
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi-110070, India; (P.S.); (T.B.)
| | - Raju K. Mandal
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan-45142, Saudi Arabia;
| | - Arif Hussain
- School of Life Sciences, Manipal Academy of Higher Education, P.O. Box 345050 Dubai, UAE;
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan-45142, Saudi Arabia;
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10
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Zare M, Jafari-Nedooshan J, Jafari M, Neamatzadeh H, Abolbaghaei SM, Foroughi E, Nasiri R, Zare-Shehneh M. Relevance of hMLH1 -93G>A, 655A>G and 1151T>A polymorphisms with colorectal cancer susceptibility: a meta-analysis based on 38 case-control studies. ACTA ACUST UNITED AC 2019; 64:942-951. [PMID: 30517243 DOI: 10.1590/1806-9282.64.10.942] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/24/2018] [Indexed: 01/02/2023]
Abstract
OBJECTIVE There has been increasing interest in the study of the association between human mutL homolog 1 (hMLH1) gene polymorphisms and risk of colorectal cancer (CRC). However, results from previous studies are inconclusive. Thus, a meta-analysis was conducted to derive a more precise estimation of the effects of this gene. METHODS A comprehensive search was conducted in the PubMed, EMBASE, Chinese Biomedical Literature databases until January 1, 2018. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association. RESULTS Finally, 38 case-control studies in 32 publications were identified met our inclusion criteria. There were 14 studies with 20668 cases and 19533 controls on hMLH1 -93G>A, 11 studies with 5,786 cases and 8,867 controls on 655A>G and 5 studies with 1409 cases and 1637 controls on 1151T>A polymorphism. The combined results showed that 655A>G and 1151T>A polymorphisms were significantly associated with CRC risk, whereas -93G>A polymorphism was not significantly associated with CRC risk. As for ethnicity, -93G>A and 655A>G polymorphisms were associated with increased risk of CRC among Asians, but not among Caucasians. More interestingly, subgroup analysis indicated that 655A>G might raise CRC risk in PCR-RFLP and HB subgroups. CONCLUSION Inconsistent with previous meta-analyses, this meta-analysis shows that the hMLH1 655A>G and 1151T>A polymorphisms might be risk factors for CRC. Moreover, the -93G>A polymorphism is associated with the susceptibility of CRC in Asian population.
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Affiliation(s)
- Mohammad Zare
- Department of General Surgery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Jamal Jafari-Nedooshan
- Department of General Surgery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammadali Jafari
- Department of Emergency Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Hossein Neamatzadeh
- Department of Medical Genetics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | | | - Elnaz Foroughi
- Department of Pediatric Dentistry, Arak university of Medical Sciences, Arak, Iran
| | - Rezvan Nasiri
- Department of Oral and Maxillofacial Surgery, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Zare-Shehneh
- Department of Medical Genetics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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11
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Shirts BH, Konnick EQ, Upham S, Walsh T, Ranola JMO, Jacobson AL, King MC, Pearlman R, Hampel H, Pritchard CC. Using Somatic Mutations from Tumors to Classify Variants in Mismatch Repair Genes. Am J Hum Genet 2018; 103:19-29. [PMID: 29887214 DOI: 10.1016/j.ajhg.2018.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/01/2018] [Indexed: 01/28/2023] Open
Abstract
Present guidelines for classification of constitutional variants do not incorporate inferences from mutations seen in tumors, even when these are associated with a specific molecular phenotype. When somatic mutations and constitutional mutations lead to the same molecular phenotype, as for the mismatch repair genes, information from somatic mutations may enable interpretation of previously unclassified variants. To test this idea, we first estimated likelihoods that somatic variants in MLH1, MSH2, MSH6, and PMS2 drive microsatellite instability and characteristic IHC staining patterns by calculating likelihoods of high versus low normalized variant read fractions of 153 mutations known to be pathogenic versus those of 760 intronic passenger mutations from 174 paired tumor-normal samples. Mutations that explained the tumor mismatch repair phenotype had likelihood ratio for high variant read fraction of 1.56 (95% CI 1.42-1.71) at sites with no loss of heterozygosity and of 26.5 (95% CI 13.2-53.0) at sites with loss of heterozygosity. Next, we applied these ratios to 165 missense, synonymous, and splice variants observed in tumors, combining in a Bayesian analysis the likelihood ratio corresponding with the adjusted variant read fraction with pretest probabilities derived from published analyses and public databases. We suggest classifications for 86 of 165 variants: 7 benign, 31 likely benign, 22 likely pathogenic, and 26 pathogenic. These results illustrate that for mismatch repair genes, characterization of tumor mutations permits tumor mutation data to inform constitutional variant classification. We suggest modifications to incorporate molecular phenotype in future variant classification guidelines.
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Affiliation(s)
- Brian H Shirts
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA.
| | - Eric Q Konnick
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sarah Upham
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Tom Walsh
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | | | - Angela L Jacobson
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Mary-Claire King
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Rachel Pearlman
- Department of Internal Medicine, Division of Human Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43221, USA
| | - Heather Hampel
- Department of Internal Medicine, Division of Human Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43221, USA
| | - Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
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12
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Cardoso MDFS, Castelletti CHM, Lima-Filho JLD, Martins DBG, Teixeira JAC. Putative biomarkers for cervical cancer: SNVs, methylation and expression profiles. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:161-173. [PMID: 28927526 DOI: 10.1016/j.mrrev.2017.06.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 02/08/2023]
Abstract
Cervical cancer is primarily caused by Human papillomavirus (HPV) infection, but other factors such as smoking habits, co-infections and genetic background, can also contribute to its development. Although this cancer is avoidable, it is the fourth most frequent type of cancer in females worldwide and can only be treated with chemotherapy and radical surgery. There is a need for biomarkers that will enable early diagnosis and targeted therapy for this type of cancer. Therefore, a systems biology pipeline was applied in order to identify potential biomarkers for cervical cancer, which show significant reports in three molecular aspects: DNA sequence variants, DNA methylation pattern and alterations in mRNA/protein expression levels. CDH1, CDKN2A, RB1 and TP53 genes were selected as putative biomarkers, being involved in metastasis, cell cycle regulation and tumour suppression. Other ten genes (CDH13, FHIT, PTEN, MLH1, TP73, CDKN1A, CACNA2D2, TERT, WIF1, APC) seemed to play a role in cervical cancer, but the lack of studies prevented their inclusion as possible biomarkers. Our results highlight the importance of these genes. However, further studies should be performed to elucidate the impact of DNA sequence variants and/or epigenetic deregulation and altered expression of these genes in cervical carcinogenesis and their potential as biomarkers for cervical cancer diagnosis and prognosis.
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Affiliation(s)
- Maria de Fátima Senra Cardoso
- Molecular Prospection and Bioinformatics Group (ProspecMol), Laboratory of Immunopathology Keizo Asami (LIKA), Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil.
| | - Carlos Henrique Madeiros Castelletti
- Molecular Prospection and Bioinformatics Group (ProspecMol), Laboratory of Immunopathology Keizo Asami (LIKA), Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil; Agronomic Institute of Pernambuco (IPA), Av. General San Martin 1371, Bongi, Recife - PE, 50761-000, Brazil
| | - José Luiz de Lima-Filho
- Laboratory of Immunopathology Keizo Asami (LIKA), Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil; Biochemistry Department, Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil
| | - Danyelly Bruneska Gondim Martins
- Molecular Prospection and Bioinformatics Group (ProspecMol), Laboratory of Immunopathology Keizo Asami (LIKA), Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil; Biochemistry Department, Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil
| | - José António Couto Teixeira
- Laboratory of Immunopathology Keizo Asami (LIKA), Federal University of Pernambuco (UFPE), Av. Prof. Moraes Rego s/n, Recife - PE, 50670-901, Brazil; Department of Biological Engineering, University of Minho (UM), Campus de Gualtar, 4710-057 Braga, Portugal
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13
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Clark CR, Starr TK. Mouse models for the discovery of colorectal cancer driver genes. World J Gastroenterol 2016; 22:815-822. [PMID: 26811627 PMCID: PMC4716079 DOI: 10.3748/wjg.v22.i2.815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/09/2015] [Accepted: 11/24/2015] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) constitutes a major public health problem as the third most commonly diagnosed and third most lethal malignancy worldwide. The prevalence and the physical accessibility to colorectal tumors have made CRC an ideal model for the study of tumor genetics. Early research efforts using patient derived CRC samples led to the discovery of several highly penetrant mutations (e.g., APC, KRAS, MMR genes) in both hereditary and sporadic CRC tumors. This knowledge has enabled researchers to develop genetically engineered and chemically induced tumor models of CRC, both of which have had a substantial impact on our understanding of the molecular basis of CRC. Despite these advances, the morbidity and mortality of CRC remains a cause for concern and highlight the need to uncover novel genetic drivers of CRC. This review focuses on mouse models of CRC with particular emphasis on a newly developed cancer gene discovery tool, the Sleeping Beauty transposon-based mutagenesis model of CRC.
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MESH Headings
- Adenomatous Polyposis Coli/genetics
- Adenomatous Polyposis Coli/metabolism
- Adenomatous Polyposis Coli/pathology
- Animals
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Colorectal Neoplasms, Hereditary Nonpolyposis/genetics
- Colorectal Neoplasms, Hereditary Nonpolyposis/metabolism
- Colorectal Neoplasms, Hereditary Nonpolyposis/pathology
- Gene Expression Regulation, Neoplastic
- Genetic Predisposition to Disease
- Humans
- Mice
- Mutation
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Phenotype
- Transposases/genetics
- Transposases/metabolism
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14
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Peña-Diaz J, Rasmussen LJ. Approaches to diagnose DNA mismatch repair gene defects in cancer. DNA Repair (Amst) 2015; 38:147-154. [PMID: 26708048 DOI: 10.1016/j.dnarep.2015.11.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/12/2015] [Accepted: 11/30/2015] [Indexed: 12/12/2022]
Abstract
The DNA repair pathway mismatch repair (MMR) is responsible for the recognition and correction of DNA biosynthetic errors caused by inaccurate nucleotide incorporation during replication. Faulty MMR leads to failure to address the mispairs or insertion deletion loops (IDLs) left behind by the replicative polymerases and results in increased mutation load at the genome. The realization that defective MMR leads to a hypermutation phenotype and increased risk of tumorigenesis highlights the relevance of this pathway for human disease. The association of MMR defects with increased risk of cancer development was first observed in colorectal cancer patients that carried inactivating germline mutations in MMR genes and the disease was named as hereditary non-polyposis colorectal cancer (HNPCC). Currently, a growing list of cancers is found to be MMR defective and HNPCC has been renamed Lynch syndrome (LS) partly to include the associated risk of developing extra-colonic cancers. In addition, a number of non-hereditary, mostly epigenetic, alterations of MMR genes have been described in sporadic tumors. Besides conferring a strong cancer predisposition, genetic or epigenetic inactivation of MMR genes also renders cells resistant to some chemotherapeutic agents. Therefore, diagnosis of MMR deficiency has important implications for the management of the patients, the surveillance of their relatives in the case of LS and for the choice of treatment. Some of the alterations found in MMR genes have already been well defined and their pathogenicity assessed. Despite this substantial wealth of knowledge, the effects of a large number of alterations remain uncharacterized (variants of uncertain significance, VUSs). The advent of personalized genomics is likely to increase the list of VUSs found in MMR genes and anticipates the need of diagnostic tools for rapid assessment of their pathogenicity. This review describes current tools and future strategies for addressing the relevance of MMR gene alterations in human disease.
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Affiliation(s)
- Javier Peña-Diaz
- Center for Healthy Aging, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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15
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Preimplantation genetic risk reduction: a new dilemma in the era of chromosomal microarrays and exome sequencing. Reprod Biomed Online 2015; 31:706-10. [DOI: 10.1016/j.rbmo.2015.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/09/2015] [Accepted: 07/09/2015] [Indexed: 12/17/2022]
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16
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Sawant A, Kothandapani A, Zhitkovich A, Sobol RW, Patrick SM. Role of mismatch repair proteins in the processing of cisplatin interstrand cross-links. DNA Repair (Amst) 2015; 35:126-36. [PMID: 26519826 DOI: 10.1016/j.dnarep.2015.10.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 12/13/2022]
Abstract
Mismatch repair (MMR) deficiency gives rise to cisplatin resistance and can lead to poor prognosis in cancers. Various models have been proposed to explain this low level of resistance caused due to loss of MMR proteins. We have shown that MMR proteins are required to maintain cisplatin interstrand cross-links (ICLs) on the DNA leading to increased cellular sensitivity. In our previous studies, we have shown that BER processing of the cisplatin ICLs is mutagenic. Polymerase β (Polβ) can generate mismatches which leads to the activation and the recruitment of mismatch repair proteins. In this paper, we distinguished between the requirement of different downstream MMR proteins for maintaining cisplatin sensitivity. We show that the MutSα (MSH2-MSH6) heterocomplex is required to maintain cisplatin sensitivity, whereas the Mutsβ complex has no effect. These results can be correlated with the increased repair of cisplatin ICLs and ICL induced DNA double strand breaks (DSBs) in the resistant cells. Moreover, we show that MLH1 proficient cells displayed a cisplatin sensitive phenotype when compared with the MLH1 deficient cells and the ATPase activity of MLH1 is essential to mediate this effect. Based on these results, we propose that MutSα as well as the downstream MMR pathway proteins are essential to maintain a cisplatin sensitive phenotype as a consequence of processing Polβ induced mismatches at sites flanking cisplatin ICLs.
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Affiliation(s)
- Akshada Sawant
- Department of Biochemistry and Cancer Biology, University of Toledo-Health Science Campus, Toledo, OH 43614, USA
| | - Anbarasi Kothandapani
- Department of Biochemistry and Cancer Biology, University of Toledo-Health Science Campus, Toledo, OH 43614, USA
| | - Anatoly Zhitkovich
- Department of Pathology and Laboratory Medicine, Alpert Medical School, Brown University, Providence, RI 02912, USA
| | - Robert W Sobol
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213, USA; Department of Oncologic Sciences, Molecular & Metabolic Oncology Program, University of South Alabama Mitchell Cancer Institute, 1660 Springhill Avenue, Mobile, AL 36604, USA
| | - Steve M Patrick
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA.
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17
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Vodicka P, Caja F, Vymetalkova V, Prochazka P, Vodickova L, Schwarzova L, Slyskova J, Kumar R, Schneiderova M. A novel c. 204 Ile68Met germline variant in exon 2 of the mutL homolog 1 gene in a colorectal cancer patient. Oncol Lett 2014; 9:183-186. [PMID: 25435955 PMCID: PMC4247117 DOI: 10.3892/ol.2014.2666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 09/26/2014] [Indexed: 01/15/2023] Open
Abstract
Mutations in the mutL homolog 1 (MLH1) gene are frequent in patients with hereditary non-polyposis colorectal cancer (CRC). The MLH1 gene was screened for mutations in patients with sporadic CRC. The nucleotide sequences for all 19 exons of MLH1 were analyzed by high resolution melting and sequenced in a group of 104 sporadic CRC patients, and the results were verified in a replication group of 1,095 patients and 1,469 controls. Different melting profiles for exon 2 of the MLH1 gene were observed in the germline DNA of one patient. Sequencing of the patient's DNA resulted in the identification of a heterozygous C>G variant at c.204, which resulted in an Ile68Met change in the amino acid. A detailed search of the National Center for Biotechnology Information and the 1000 Genomes databases indicated that the detected variant was unique. According to the SIFT and PolyPhen-2 algorithms, the substitution of Ile to Met was predicted to decrease the activity of the MLH1 protein. The newly identified, functional germline variant was not present in any other CRC patient or control. Thus, a novel germline variant in the MLH1 gene was identified, representing a rare event in sporadic CRC. The occurrence and relevance of this mutation in other types of cancer requires additional investigation.
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Affiliation(s)
- Pavel Vodicka
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic ; Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic
| | - Fabian Caja
- Department of Immunology and Gnotobiology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic
| | - Veronika Vymetalkova
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic ; Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic
| | - Pavel Prochazka
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic ; Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic
| | - Ludmila Vodickova
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic ; Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic ; Department of Toxicogenomics, National Institute of Public Health, Prague 10042, Czech Republic
| | - Lucie Schwarzova
- Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic
| | - Jana Slyskova
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic ; Department of Molecular Genetics, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague 12800, Czech Republic
| | - Rajiv Kumar
- Division of Molecular Genetic Epidemiology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg 69121, Germany
| | - Michaela Schneiderova
- Department of Surgery, General University Hospital in Prague, Prague 12800, Czech Republic
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18
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Geurts-Giele WRR, Leenen CHM, Dubbink HJ, Meijssen IC, Post E, Sleddens HFBM, Kuipers EJ, Goverde A, van den Ouweland AMW, van Lier MGF, Steyerberg EW, van Leerdam ME, Wagner A, Dinjens WNM. Somatic aberrations of mismatch repair genes as a cause of microsatellite-unstable cancers. J Pathol 2014; 234:548-59. [PMID: 25111426 DOI: 10.1002/path.4419] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 07/28/2014] [Accepted: 08/06/2014] [Indexed: 12/17/2022]
Abstract
Lynch syndrome (LS) is caused by germline mutations in mismatch repair (MMR) genes, resulting in microsatellite-unstable tumours. Approximately 35% of suspected LS (sLS) patients test negative for germline MMR gene mutations, hampering conclusive LS diagnosis. The aim of this study was to investigate somatic MMR gene aberrations in microsatellite-unstable colorectal and endometrial cancers of sLS patients negative for germline MMR gene mutations. Suspected LS cases were selected from a retrospective Clinical Genetics Department diagnostic cohort and from a prospective multicentre population-based study on LS in The Netherlands. In total, microsatellite-unstable tumours of 40 sLS patients (male/female 20/20, median age 57 years) were screened for somatic MMR gene mutations by next-generation sequencing. In addition, loss of heterozygosity (LOH) of the affected MMR genes in these tumours as well as in 68 LS-associated tumours and 27 microsatellite-unstable tumours with MLH1 promoter hypermethylation was studied. Of the sLS cases, 5/40 (13%) tumours had two pathogenic somatic mutations and 16/40 (40%) tumours had a (likely) pathogenic mutation and LOH. Overall, LOH of the affected MMR gene locus was observed in 24/39 (62%) tumours with informative LOH markers. Of the LS cases and the tumours with MLH1 promoter hypermethylation, 39/61 (64%) and 2/21 (10%) tumours, respectively, demonstrated LOH. Half of microsatellite-unstable tumours of sLS patients without germline MMR gene mutations had two (likely) deleterious somatic MMR gene aberrations, indicating their sporadic origin. Therefore, we advocate adding somatic mutation and LOH analysis of the MMR genes to the molecular diagnostic workflow of LS.
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Affiliation(s)
- Willemina R R Geurts-Giele
- Department of Pathology, Erasmus MC Cancer Institute, University Medical Centre, Rotterdam, The Netherlands
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19
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Pineda M, González-Acosta M, Thompson BA, Sánchez R, Gómez C, Martínez-López J, Perea J, Caldés T, Rodríguez Y, Landolfi S, Balmaña J, Lázaro C, Robles L, Capellá G, Rueda D. Detailed characterization of MLH1 p.D41H and p.N710D variants coexisting in a Lynch syndrome family with conserved MLH1 expression tumors. Clin Genet 2014; 87:543-8. [PMID: 25060679 DOI: 10.1111/cge.12467] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 12/26/2022]
Abstract
Lynch syndrome (LS) is an autosomal dominant cancer-susceptibility disease caused by inactivating germline mutations in mismatch repair (MMR) genes. Variants of unknown significance (VUS) are often detected in mutational analysis of MMR genes. Here we describe a large family fulfilling Amsterdam I criteria carrying two rare VUS in the MLH1 gene: c.121G > C (p.D41H) and c.2128A > G (p.N710D). Collection of clinico-pathological data, multifactorial analysis, in silico predictions, and functional analyses were used to elucidate the clinical significance of the identified MLH1 VUS. Only the c.121G > C variant cosegregated with LS-associated tumors in the family. Diagnosed colorectal tumors were microsatellite unstable although immunohistochemical staining revealed no loss of MMR proteins expression. Multifactorial likelihood analysis classified c.2128A > G as a non-pathogenic variant and c.121G > C as pathogenic. In vitro functional tests revealed impaired MMR activity and diminished expression of c.121G > C. Accordingly, the N710 residue is located in the unconserved MLH1 C-terminal domain, whereas D41 is highly conserved and located in the ATPase domain. The obtained results will enable adequate genetic counseling of c.121G > C and c.2128A > G variant carriers and their families. Furthermore, they exemplify how cumulative data and comprehensive analyses are mandatory to refine the classification of MMR variants.
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Affiliation(s)
- M Pineda
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
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Sun MZ, Ju HX, Zhou ZW, Jin H, Zhu R. Single nucleotide polymorphisms of DNA mismatch repair genes MSH2 and MLH1 confer susceptibility to esophageal cancer. Int J Clin Exp Med 2014; 7:2329-2333. [PMID: 25232430 PMCID: PMC4161590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/27/2014] [Indexed: 06/03/2023]
Abstract
Defects in DNA mismatch repair genes like MSH2 and MLH1 confer increased risk of cancers. Here, single nucleotide polymorphisms (SNPs) in MSH2 and MLH1 were investigated for their potential contribution to the risk of esophageal cancer. This study recruited 614 participants from Affiliated Yancheng Hospital, School of Medicine, Southeast University, of which 289 were patients with esophageal cancer, and the remainder was healthy individuals who served as a control group. Two SNPs, MSH2 c.2063T>G and MLH1 IVS14-19A>G, were genotyped using PCR-RFLP. Statistical analysis was performed using chi-square test and logistic regression analysis. Carriers of the MSH2 c.2063G allele were at significantly higher risk for esophageal cancer compared to individuals with the TT genotype [OR = 3.36, 95% confidence interval (CI): 1.18-11.03]. The MLH1 IVS14-19A>G allele also conferred significantly increased (1.70-fold) for esophageal cancer compared to the AA genotype (OR = 1.70, 95% CI: 1.13-5.06). Further, the variant alleles interacted such that individuals with the susceptible genotypes at both MSH2 and MLH1 had a significantly exacerbated risk for esophageal cancer (OR = 12.38, 95% CI: 3.09-63.11). In brief, SNPs in the DNA mismatch repair genes MSH2 and MLH1 increase the risk of esophageal cancer. Molecular investigations are needed to uncover the mechanism behind their interaction effect.
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Affiliation(s)
- Ming-Zhong Sun
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University Yancheng 224001, Jiangsu, China
| | - Hui-Xiang Ju
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University Yancheng 224001, Jiangsu, China
| | - Zhong-Wei Zhou
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University Yancheng 224001, Jiangsu, China
| | - Hao Jin
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University Yancheng 224001, Jiangsu, China
| | - Rong Zhu
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University Yancheng 224001, Jiangsu, China
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21
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Ezzatizadeh V, Sandi C, Sandi M, Anjomani-Virmouni S, Al-Mahdawi S, Pook MA. MutLα heterodimers modify the molecular phenotype of Friedreich ataxia. PLoS One 2014; 9:e100523. [PMID: 24971578 PMCID: PMC4074104 DOI: 10.1371/journal.pone.0100523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/28/2014] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA), the most common autosomal recessive ataxia disorder, is caused by a dynamic GAA repeat expansion mutation within intron 1 of FXN gene, resulting in down-regulation of frataxin expression. Studies of cell and mouse models have revealed a role for the mismatch repair (MMR) MutS-heterodimer complexes and the PMS2 component of the MutLα complex in the dynamics of intergenerational and somatic GAA repeat expansions: MSH2, MSH3 and MSH6 promote GAA repeat expansions, while PMS2 inhibits GAA repeat expansions. METHODOLOGY/PRINCIPAL FINDINGS To determine the potential role of the other component of the MutLα complex, MLH1, in GAA repeat instability in FRDA, we have analyzed intergenerational and somatic GAA repeat expansions from FXN transgenic mice that have been crossed with Mlh1 deficient mice. We find that loss of Mlh1 activity reduces both intergenerational and somatic GAA repeat expansions. However, we also find that loss of either Mlh1 or Pms2 reduces FXN transcription, suggesting different mechanisms of action for Mlh1 and Pms2 on GAA repeat expansion dynamics and regulation of FXN transcription. CONCLUSIONS/SIGNIFICANCE Both MutLα components, PMS2 and MLH1, have now been shown to modify the molecular phenotype of FRDA. We propose that upregulation of MLH1 or PMS2 could be potential FRDA therapeutic approaches to increase FXN transcription.
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Affiliation(s)
- Vahid Ezzatizadeh
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Chiranjeevi Sandi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Madhavi Sandi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Sara Anjomani-Virmouni
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Sahar Al-Mahdawi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
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22
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Mensenkamp AR, Vogelaar IP, van Zelst-Stams WAG, Goossens M, Ouchene H, Hendriks-Cornelissen SJB, Kwint MP, Hoogerbrugge N, Nagtegaal ID, Ligtenberg MJL. Somatic mutations in MLH1 and MSH2 are a frequent cause of mismatch-repair deficiency in Lynch syndrome-like tumors. Gastroenterology 2014; 146:643-646.e8. [PMID: 24333619 DOI: 10.1053/j.gastro.2013.12.002] [Citation(s) in RCA: 255] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 01/03/2023]
Abstract
Lynch syndrome is caused by germline mutations in the mismatch repair (MMR) genes. Tumors are characterized by microsatellite instability (MSI). However, a considerable number of MSI-positive tumors have no known molecular mechanism of development. By using Sanger and ion semiconductor sequencing, 25 MSI-positive tumors were screened for somatic mutations and loss of heterozygosity in mutL homolog 1 (MLH1) and mutS homolog 2 (MSH2). In 13 of 25 tumors (8 MLH1-deficient and 5 MSH2-deficient tumors), we identified 2 somatic mutations in these genes. We conclude that 2 acquired events explain the MMR-deficiency in more than 50% of the MMR-deficient tumors without causal germline mutations or promoter methylation.
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Affiliation(s)
- Arjen R Mensenkamp
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.
| | - Ingrid P Vogelaar
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Monique Goossens
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Hicham Ouchene
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Michael P Kwint
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Nicoline Hoogerbrugge
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | - Iris D Nagtegaal
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Marjolijn J L Ligtenberg
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands; Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
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23
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Xu JL, Yin ZQ, Huang MD, Wang XF, Gao W, Liu LX, Wang RS, Huang PW, Yin YM, Liu P, Shu YQ. MLH1 polymorphisms and cancer risk: a meta-analysis based on 33 case-control studies. Asian Pac J Cancer Prev 2012; 13:901-7. [PMID: 22631669 DOI: 10.7314/apjcp.2012.13.3.901] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Cumulative evidence suggests that MLH1, the key component in the mismatch pathway, plays an important role in human cancers. Two potential functional polymorphisms (-93G>A and I219V) of MLH1 have been implicated in cancer risk. The aim of this meta-analysis was to summarize the evidence for associations. METHODS Eligible studies were identified by searching the electronic literature PubMed, ScienceDirect and Embase databases for relevant reports and bibliographies. Studies were included if of case-control design investigating MLH1 polymorphisms (-93G>A and I219V) and cancer risk with sufficient raw data for analysis. Odds ratios (OR) and 95% confidence intervals (95% CI) were used to evaluate the strength of associations. RESULTS Our meta-analysis from 33 published case-control studies showed the variant A allele of -93G>A polymorphism to be associated with increased risk in all genetic models (AA vs. GG: OR = 1.22, 95% CI: 1.03-1.44), especially among non-Asians (AA vs. GG: OR = 1.28, 95% CI: 1.04-1.58). For the I219V polymorphism, however, there was no main effect associated with overall cancer risk in any genetic model. CONCLUSIONS The meta-analysis suggested that the MLH1 -93G>A polymorphism may be a biomarker of cancer susceptibility. Large sample association studies and assessment of gene-to-gene as well as gene-to-environment interactions are required to confirm these findings.
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Affiliation(s)
- Jia-Li Xu
- Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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24
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Heinen CD, Juel Rasmussen L. Determining the functional significance of mismatch repair gene missense variants using biochemical and cellular assays. Hered Cancer Clin Pract 2012; 10:9. [PMID: 22824075 PMCID: PMC3434035 DOI: 10.1186/1897-4287-10-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/28/2012] [Indexed: 12/15/2022] Open
Abstract
With the discovery that the hereditary cancer susceptibility disease Lynch syndrome (LS) is caused by deleterious germline mutations in the DNA mismatch repair (MMR) genes nearly 20 years ago, genetic testing can now be used to diagnose this disorder in patients. A definitive diagnosis of LS can direct how clinicians manage the disease as well as prevent future cancers for the patient and their families. A challenge emerges, however, when a germline missense variant is identified in a MMR gene in a suspected LS patient. The significance of a single amino acid change in these large repair proteins is not immediately obvious resulting in them being designated variants of uncertain significance (VUS). One important strategy for resolving this uncertainty is to determine whether the variant results in a non-functional protein. The ability to reconstitute the MMR reaction in vitro has provided an important experimental tool for studying the functional consequences of VUS. However, beyond this repair assay, a number of other experimental methods have been developed that allow us to test the effect of a VUS on discrete biochemical steps or other aspects of MMR function. Here, we describe some of these assays along with the challenges of using such assays to determine the functional consequences of MMR VUS which, in turn, can provide valuable insight into their clinical significance. With increased gene sequencing in patients, the number of identified VUS has expanded dramatically exacerbating this problem for clinicians. However, basic science research laboratories around the world continue to expand our knowledge of the overall MMR molecular mechanism providing new opportunities to understand the functional significance, and therefore pathogenic significance, of VUS.
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Affiliation(s)
- Christopher D Heinen
- Neag Comprehensive Cancer Center and Center for Molecular Medicine, University of Connecticut Health Center, 233 Farmington Avenue, ML3101 Farmington, CT, USA.
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25
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Borràs E, Pineda M, Brieger A, Hinrichsen I, Gómez C, Navarro M, Balmaña J, Ramón y Cajal T, Torres A, Brunet J, Blanco I, Plotz G, Lázaro C, Capellá G. Comprehensive functional assessment of MLH1 variants of unknown significance. Hum Mutat 2012; 33:1576-88. [PMID: 22736432 DOI: 10.1002/humu.22142] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/29/2012] [Indexed: 12/15/2022]
Abstract
Lynch syndrome is associated with germline mutations in DNA mismatch repair (MMR) genes. Up to 30% of DNA changes found are variants of unknown significance (VUS). Our aim was to assess the pathogenicity of eight MLH1 VUS identified in patients suspected of Lynch syndrome. All of them are novel or not previously characterized. For their classification, we followed a strategy that integrates family history, tumor pathology, and control frequency data with a variety of in silico and in vitro analyses at RNA and protein level, such as MMR assay, MLH1 and PMS2 expression, and subcellular localization. Five MLH1 VUS were classified as pathogenic: c.[248G>T(;)306G>C], c.[780C>G;788A>C], and c.791-7T>A affected mRNA processing, whereas c.218T>C (p.L73P) and c.244A>G [corrected] (p.T82A) impaired MMR activity. Two other VUS were considered likely neutral: the silent c.702G>A variant did not affect mRNA processing or stability, and c.974G>A (p.R325Q) did not influence MMR function. In contrast, variant c.25C>T (p.R9W) could not be classified, as it associated with intermediate levels of MMR activity. Comprehensive functional assessment of MLH1 variants was useful in their classification and became relevant in the diagnosis and genetic counseling of carrier families.
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Affiliation(s)
- Ester Borràs
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Spain
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26
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Aggarwal M, Brosh RM. Functional analyses of human DNA repair proteins important for aging and genomic stability using yeast genetics. DNA Repair (Amst) 2012; 11:335-48. [PMID: 22349084 DOI: 10.1016/j.dnarep.2012.01.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 01/24/2012] [Indexed: 12/18/2022]
Abstract
Model systems have been extremely useful for studying various theories of aging. Studies of yeast have been particularly helpful to explore the molecular mechanisms and pathways that affect aging at the cellular level in the simple eukaryote. Although genetic analysis has been useful to interrogate the aging process, there has been both interest and debate over how functionally conserved the mechanisms of aging are between yeast and higher eukaryotes, especially mammalian cells. One area of interest has been the importance of genomic stability for age-related processes, and the potential conservation of proteins and pathways between yeast and human. Translational genetics have been employed to examine the functional roles of mammalian proteins using yeast as a pliable model system. In the current review recent advancements made in this area are discussed, highlighting work which shows that the cellular functions of human proteins in DNA repair and maintenance of genomic stability can be elucidated by genetic rescue experiments performed in yeast.
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Affiliation(s)
- Monika Aggarwal
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, Baltimore, MD 21224, United States
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27
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Zhi Y, Yu J, Liu Y, Wei Q, Yuan F, Zhou X, Song B, Chen Z, Yang J. Interaction between polymorphisms of DNA repair genes significantly modulated bladder cancer risk. Int J Med Sci 2012; 9:498-505. [PMID: 22927776 PMCID: PMC3427955 DOI: 10.7150/ijms.4799] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 07/30/2012] [Indexed: 12/04/2022] Open
Abstract
DNA repair is a primary defense mechanism against damage caused by exogenous and endogenous sources. We examined the associations between bladder cancer and 7 polymorphisms from 5 genes involved in the maintenance of genetic stability (MMR: MLH1-93G>A; BER: XRCC1--77T>C and Arg399Gln; NER:XPC Lys939Gln and PAT +/-; DSBR:ATM G5557A and XRCC7 G6721T) in 302 incident bladder cancer cases and 311 hospital controls. Genotyping was done using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. The homozygous variant of XRCC7 G6721T (Odds Ratio [OR]: 2.36; 95% Confidence Interval [CI]: 1.13-4.92) was associated with increased bladder cancer risk. In an analysis of combined genotypes, the combination of XRCC1Arg399Gln (Gln allele) with XRCC1-77 T/T led to an increase in risk (OR: 1.61; 95% CI: 1.10-2.36). Moreover, when the XPCLys939Gln (Gln allele) (nucleotide excision repair [NER]) was present together with XRCC7 (T allele) (double strand break repair [DSBR]), the bladder cancer risk dramatically increased (OR: 4.42; 95% CI: 1.23-15.87). Our results suggest that there are multigenic variations in the DNA repair pathway involved in bladder cancer susceptibility, despite the existence of ethnic group differences.
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Affiliation(s)
- Yi Zhi
- Department of Cell Biology, Third Military Medical University, Chongqing, China
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28
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Ye BF, Li HW, Pang ZL, Li H, Tian Q, Chen Y, Guo WJ, Li XM, Wang HJ. Significance of EphA2, hMLH1 and hMSH2 mRNA expression in esophageal squamous cell carcinoma in Chinese Uygur and Han patients in Xinjiang. Shijie Huaren Xiaohua Zazhi 2009; 17:3635-3639. [DOI: 10.11569/wcjd.v17.i35.3635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the significance of Ephrin A2 (EphA2), human mutl homolog 1 (hMLH1) and hMSH2 mRNA expression and explore their relationship with clinicopathological parameters in esophageal carcinoma in Chinese Uygur and Han patients in Xinjiang.
METHODS: The expression of EphA2, hMLH1 and hMSH2 mRNAs was detected by reverse transcription-polymerase chain reaction (RT-PCR) in esophageal carcinoma and distant non-carcinoma tissues from 30 Chinese Uygur patients and 30 Chinese Han patients.
RESULTS: The positive rate of EphA2 expression was significantly higher in esophageal carcinoma than in distant non-carcinoma tissue (71.7% vs 46.7%; χ2 = 7.761, P = 0.005). The differential expression rate of EphA2 was 56.7% between esophageal carcinoma and distant non-carcinoma tissue. The expression of EphA2 was correlated with the depth of invasion, lymph node metastasis and patients' nationality in esophageal carcinoma (P < 0.05). The positive rate of hMLH1 expression was significantly lower in esophageal carcinoma than in distant non-carcinoma tissue (63.3% vs 88.3%, χ2 = 10.231, P = 0.001). The differential expression rate of hMLH1 was 75.0% between esophageal carcinoma and distant non-carcinoma tissue. There was significant difference in the positive rate of hMSH2 expression between carcinoma and non-carcinoma tissue (83.3% vs 86.7%, χ2 = 0.261, P = 0.609). The differential expression rate of hMSH2 was 81.7% between esophageal carcinoma and distant non-carcinoma tissue. Significant correlations were noted between the expression of hMLH1 and hMSH2 and tumor stage (both P < 0.05). The expression of EphA2 was negatively correlated with hMLH1 and hMSH2 expression.
CONCLUSION: EphA2, hMLH1 and hMSH2 play important roles in the carcinogenesis and metastasis of esophageal cancer. Combined detection of EphA2, hMLH1 and hMSH2 expression may be used to screen for esophageal carcinoma in a high-risk population.
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29
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Humanizing mismatch repair in yeast: towards effective identification of hereditary non-polyposis colorectal cancer alleles. Biochem Soc Trans 2008; 35:1525-8. [PMID: 18031259 DOI: 10.1042/bst0351525] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The correction of replication errors is an essential component of genetic stability. This is clearly demonstrated in humans by the observation that mutations in mismatch repair genes lead to HNPCC (hereditary non-polyposis colorectal cancer). This disease accounts for as many as 2-3% of colon cancers. Of these, most of them are in the two central components of mismatch repair, MLH1 (mutL homologue 1) and MSH2 (mutS homologue 2). MLH1 and MSH2 function as a complex with two other genes PMS2 and MSH6. Mismatch repair genes, and the mechanism that ensures that incorrectly paired bases are removed, are conserved from prokaryotes to human. Thus yeast can serve as a model organism for analysing mutations/polymorphisms found in human mismatch repair genes for their effect on post-replicative repair. To date, this has predominantly been accomplished by making the analogous mutations in yeast genes. However, this approach is only useful for the most highly conserved regions. Here, we discuss some of the benefits and technical difficulties involved in expressing human genes in yeast. Modelling human mismatch repair in yeast will allow the assessment of any functional effect of novel polymorphisms found in patients diagnosed with colon cancers.
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Distinct effects of the recurrent Mlh1G67R mutation on MMR functions, cancer, and meiosis. Proc Natl Acad Sci U S A 2008; 105:4247-52. [PMID: 18337503 DOI: 10.1073/pnas.0800276105] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mutations in the human DNA mismatch repair (MMR) gene MLH1 are associated with hereditary nonpolyposis colorectal cancer (Lynch syndrome, HNPCC) and a significant proportion of sporadic colorectal cancer. The inactivation of MLH1 results in the accumulation of somatic mutations in the genome of tumor cells and resistance to the genotoxic effects of a variety of DNA damaging agents. To study the effect of MLH1 missense mutations on cancer susceptibility, we generated a mouse line carrying the recurrent Mlh1(G67R) mutation that is located in one of the ATP-binding domains of Mlh1. Although the Mlh1(G67R) mutation resulted in DNA repair deficiency in homozygous mutant mice, it did not affect the MMR-mediated cellular response to DNA damage, including the apoptotic response of epithelial cells in the intestinal mucosa to cisplatin, which was defective in Mlh1(-/-) mice but remained normal in Mlh1(G67R/G67R) mice. Similar to Mlh1(-/-) mice, Mlh1(G67R/G67R) mutant mice displayed a strong cancer predisposition phenotype. However, in contrast to Mlh1(-/-) mice, Mlh1(G67R/G67R) mutant mice developed significantly fewer intestinal tumors, indicating that Mlh1 missense mutations can affect MMR tumor suppressor functions in a tissue-specific manner. In addition, Mlh1(G67R/G67R) mice were sterile because of the inability of the mutant Mlh1(G67R) protein to interact with meiotic chromosomes at pachynema, demonstrating that the ATPase activity of Mlh1 is essential for fertility in mammals.
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31
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An Y, Jin G, Wang H, Wang Y, Liu H, Li R, Wang H, Qian J, Sun W, Wang Y, Ma H, Miao R, Hu Z, Jin L, Wei Q, Shen H, Huang W, Lu D. Polymorphisms in hMLH1 and risk of early-onset lung cancer in a southeast Chinese population. Lung Cancer 2007; 59:164-70. [PMID: 17870204 DOI: 10.1016/j.lungcan.2007.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 07/27/2007] [Accepted: 08/06/2007] [Indexed: 02/07/2023]
Abstract
DNA mismatch repair (MMR) plays an important role in maintaining genome stability. Defects in MMR genes have been involved in several types of sporadic and hereditary cancers. hMLH1 is considered one of central members of the MMR pathway. We conducted a hospital-based case-control study to investigate associations of common variations in the hMLH1 gene and risk of lung cancer. A total of 500 cases and 517 controls were genotyped for seven SNPs in hMLH1. Overall, the rs1799977 I219V polymorphism was marginally associated with the risk of lung cancer (P=0.055). This association was much stronger in younger patients (P=0.01; odds ratio, 5.28; 95% CI 1.45-19.21) and lung squamous cell carcinoma (P=0.006; odds ratio, 3.65; 95% CI 1.44-9.24). These findings indicate that the hMLH1 rs1799977 polymorphism may contribute to the etiology of early-onset lung cancer as well as some specific subtype of lung cancer. Larger association studies are warranted to validate our findings and mechanistic studies are needed to elucidate the underlying molecular mechanisms of the association.
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Affiliation(s)
- Yu An
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Handan Road, Shanghai 200433, China
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32
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Blasi MF, Ventura I, Aquilina G, Degan P, Bertario L, Bassi C, Radice P, Bignami M. A human cell-based assay to evaluate the effects of alterations in the MLH1 mismatch repair gene. Cancer Res 2006; 66:9036-44. [PMID: 16982745 DOI: 10.1158/0008-5472.can-06-1896] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We describe a new approach to investigate alterations in the human MLH1 mismatch repair (MMR) gene. This is based on complementation of the phenotype of a MLH1-defective subclone of the ovarian carcinoma A2780 cells by transfection of vectors encoding altered MLH1 proteins. Measurements of resistance (tolerance) to methylating agents, mutation rate at HPRT, microsatellite instability (MSI), and steady-state levels of DNA 8-oxoguanine were used to define the MMR status of transfected clones. The approach was validated by transfecting cDNA of wild-type (WT) MLH1, cDNAs bearing two previously identified polymorphisms (I219V and I219L) and two with confirmed hereditary nonpolyposis colorectal cancer (HNPCC) syndrome mutations (G224D and G67R). A low-level expression of two MLH1 polymorphisms partially reversed methylation tolerance and the mutator phenotype, including MSI. Higher levels of I219V resulted in full restoration of these properties to WT. Increased expression of I129L did not fully complement the MLH1 defect, because there was a simultaneous escalation in the level of oxidative DNA damage. The findings confirmed the important relationship between deficient MMR and increased levels of oxidative DNA damage. Mutations from Italian HNPCC families (G224D, G67R, N635S, and K618A) were all ineffective at reversing the phenotype of the MLH1-defective A2780 cells. One (K618A) was identified as a low penetrance mutation based on clinical and genetic observations.
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Affiliation(s)
- Monica Francesca Blasi
- Unit of Experimental Carcinogenesis, Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Rome, Italy
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33
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Woods MO, Hyde AJ, Curtis FK, Stuckless S, Green JS, Pollett AF, Robb JD, Green RC, Croitoru ME, Careen A, Chaulk JAW, Jegathesan J, McLaughlin JR, Gallinger SS, Younghusband HB, Bapat BV, Parfrey PS. High frequency of hereditary colorectal cancer in Newfoundland likely involves novel susceptibility genes. Clin Cancer Res 2006; 11:6853-61. [PMID: 16203774 DOI: 10.1158/1078-0432.ccr-05-0726] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Newfoundland has one of the highest rates of colorectal cancer in North America. The most common hereditary form of colorectal cancer is hereditary nonpolyposis colorectal cancer caused by mutations in genes involved in mismatch repair. Our purpose was to determine the proportion of hereditary colorectal cancer and to determine the genetic basis of disease in both population and clinically referred cohorts from Newfoundland. EXPERIMENTAL DESIGN Seventy-eight colorectal cancer patients were accrued over a 2-year period from the Avalon Peninsula of Newfoundland. We also examined 31 hereditary nonpolyposis colorectal cancer-like families, which had been referred to the Provincial Medical Genetics Program. Tumors from probands were tested by immunohistochemistry for deficiencies in MLH1, MSH2, and MSH6 proteins and tested for DNA microsatellite instability. Mutation analyses of MLH1, MSH2, and MSH6 were undertaken by direct sequencing and an assay to detect deletions, amplifications, and rearrangements in MSH2 and MLH1. RESULTS We identified eight population-based families that fulfill the Amsterdam I or II criteria, 4 (50%) of which seem to have hereditary cancer not attributable to the most commonly mutated mismatch repair genes. In addition, in 16 of 21 (76%) referred families fulfilling Amsterdam I or II criteria, no mutations were found in the three most commonly altered mismatch repair genes, and tumor analyses corroborated these findings. CONCLUSIONS It seems that strong and novel genetic causes of hereditary colorectal cancer are responsible for a high proportion of colorectal cancer in this population. Conditions are suitable for the identification of these genes by linkage studies of large Newfoundland cancer families.
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Affiliation(s)
- Michael O Woods
- Discipline of Genetics, Department of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
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Abdel-Rahman WM, Mecklin JP, Peltomäki P. The genetics of HNPCC: application to diagnosis and screening. Crit Rev Oncol Hematol 2006; 58:208-20. [PMID: 16434208 DOI: 10.1016/j.critrevonc.2005.11.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 10/30/2005] [Accepted: 11/09/2005] [Indexed: 01/26/2023] Open
Abstract
Hereditary nonpolyposis colorectal cancer syndrome (HNPCC; Lynch Syndrome) is the most common form of hereditary colorectal cancers. Predisposed individuals have increased lifetime risk of developing colorectal, endometrial and other cancers. The syndrome is primarily due to heterozygous germline mutations in one of the mismatch repair genes; mainly MLH1, MSH2, MSH6 and PMS2. The resulting mismatch repair deficiency leads to microsatellite instability which is the hallmark of tumors arising within this syndrome, as well as a variable proportion of sporadic tumors. Diagnostic guidelines and criteria for molecular testing of suspected families have been proposed and are continuously updated. However, not all families fulfilling these criteria show mutations in mismatch repair genes and/or microsatellite instability implicating other, as yet unknown, carcinogenic mechanisms and predisposition genes. This subset of tumors is the focus of current clinical and molecular research. This review addresses recent advances in the field of HNPCC research and their applications in the management of affected individuals and families.
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Abstract
BACKGROUND & AIMS Germline mutations in mismatch repair genes are associated with hereditary nonpolyposis colorectal cancer. A significant proportion of mutations are nontruncating and associated with a variability of clinical phenotype and microsatellite instability and with occasional presence of residual protein in tumor tissue that suggests impaired functional activity but not total lack of mismatch repair. To address pathogenic significance and mechanism of pathogenicity, we studied the functionality of 31 nontruncating MLH1 mutations found in clinically characterized colorectal cancer families and 3 other variations listed in a mutation database. METHODS Mutations constructed by site-directed mutagenesis were studied for protein expression/stability, subcellular localization, protein-protein interaction, and repair efficiency. The genetic and biochemical data were correlated with clinical data. Finally, comparative sequence analysis was performed to assess the value of sequence homology as a tool for predicting functional results. RESULTS Altogether, 22 mutations were pathogenic in more than one assay, 2 variants were impaired in one assay, and 10 variants acted like wild-type protein. Twenty of 34 mutations affected the quantity of MLH1 protein, whereas only 15 mainly amino-terminal mutations were defective in an in vitro repair assay. Comparative sequence analysis correctly predicted functional studies for 82% of variants. CONCLUSIONS Pathogenic nontruncating alterations in MLH1 may interfere with different biochemical mechanisms but generally more than one. The severe biochemical defects are mirrored by phenotypic characteristics such as early age at onset and high microsatellite instability, whereas variants with no or mild defects in functionality are associated with variable clinical phenotypes.
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