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Wang Y, Wang C, Zhong R, Wang L, Sun L. Research progress of DNA methylation in colorectal cancer (Review). Mol Med Rep 2024; 30:154. [PMID: 38963030 PMCID: PMC11240861 DOI: 10.3892/mmr.2024.13278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/14/2024] [Indexed: 07/05/2024] Open
Abstract
DNA methylation is one of the earliest and most significant epigenetic mechanisms discovered. DNA methylation refers, in general, to the addition of a methyl group to a specific base in the DNA sequence under the catalysis of DNA methyltransferase, with S‑adenosine methionine as the methyl donor, via covalent bonding and chemical modifications. DNA methylation is an important factor in inducing cancer. There are different types of DNA methylation, and methylation at different sites plays different roles. It is well known that the progression of colorectal cancer (CRC) is affected by the methylation of key genes. The present review did not only discuss the potential relationship between DNA methylation and CRC but also discussed how DNA methylation affects the development of CRC by affecting key genes. Furthermore, the clinical significance of DNA methylation in CRC was highlighted, including that of the therapeutic targets and biomarkers of methylation; and the importance of DNA methylation inhibitors was discussed as a novel strategy for treatment of CRC. The present review did not only focus upon the latest research findings, but earlier reviews were also cited as references to older literature.
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Affiliation(s)
- Yuxin Wang
- Emergency Department, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116027, P.R. China
| | - Chengcheng Wang
- Comparative Medicine Department of Researching and Teaching, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Ruiqi Zhong
- Comparative Medicine Department of Researching and Teaching, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Liang Wang
- Comparative Medicine Department of Researching and Teaching, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Lei Sun
- Emergency Department, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116027, P.R. China
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2
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Saikia S, Postwala H, Athilingam VP, Anandan A, Padma VV, Kalita PP, Chorawala M, Prajapati B. Single Nucleotide Polymorphisms (SNPs) in the Shadows: Uncovering their Function in Non-Coding Region of Esophageal Cancer. Curr Pharm Biotechnol 2024; 25:1915-1938. [PMID: 38310451 DOI: 10.2174/0113892010265004231116092802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 02/05/2024]
Abstract
Esophageal cancer is a complex disease influenced by genetic and environmental factors. Single nucleotide polymorphisms (SNPs) in non-coding regions of the genome have emerged as crucial contributors to esophageal cancer susceptibility. This review provides a comprehensive overview of the role of SNPs in non-coding regions and their association with esophageal cancer. The accumulation of SNPs in the genome has been implicated in esophageal cancer risk. Various studies have identified specific locations in the genome where SNPs are more likely to occur, suggesting a location-specific response. Chromatin conformational studies have shed light on the localization of SNPs and their impact on gene transcription, posttranscriptional modifications, gene expression regulation, and histone modification. Furthermore, miRNA-related SNPs have been found to play a significant role in esophageal squamous cell carcinoma (ESCC). These SNPs can affect miRNA binding sites, thereby altering target gene regulation and contributing to ESCC development. Additionally, the risk of ESCC has been linked to base excision repair, suggesting that SNPs in this pathway may influence disease susceptibility. Somatic DNA segment alterations and modified expression quantitative trait loci (eQTL) have also been associated with ESCC. These alterations can lead to disrupted gene expression and cellular processes, ultimately contributing to cancer development and progression. Moreover, SNPs have been found to be associated with the long non-coding RNA HOTAIR, which plays a crucial role in ESCC pathogenesis. This review concludes with a discussion of the current and future perspectives in the field of SNPs in non-coding regions and their relevance to esophageal cancer. Understanding the functional implications of these SNPs may lead to the identification of novel therapeutic targets and the development of personalized approaches for esophageal cancer prevention and treatment.
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Affiliation(s)
- Surovi Saikia
- Department of Natural Product Chemistry, Translational Research Laboratory, Bharathiar University, Coimbatore - 641 046, Tamil Nadu, India
| | - Humzah Postwala
- Department of Pharmacology and Pharmacy Practice, L. M. College of Pharmacy, Ahmedabad, India
| | - Vishnu Prabhu Athilingam
- Department of Natural Product Chemistry, Translational Research Laboratory, Bharathiar University, Coimbatore - 641 046, Tamil Nadu, India
| | - Aparna Anandan
- Department of Natural Product Chemistry, Translational Research Laboratory, Bharathiar University, Coimbatore - 641 046, Tamil Nadu, India
| | - V Vijaya Padma
- Department of Natural Product Chemistry, Translational Research Laboratory, Bharathiar University, Coimbatore - 641 046, Tamil Nadu, India
| | - Partha P Kalita
- Program of Biotechnology, Assam Down Town University, Panikhaiti, Guwahati 781026, Assam, India
| | - Mehul Chorawala
- Department of Pharmacology and Pharmacy Practice, L. M. College of Pharmacy, Ahmedabad, India
| | - Bhupendra Prajapati
- Department of Pharmaceutics and Pharmaceutical Technology, Shree. S. K. Patel College of Pharmaceutical Education and Research, Ganpat University, Kherva, Gujarat, India
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Papin C, Ibrahim A, Sabir JSM, Le Gras S, Stoll I, Albiheyri RS, Zari AT, Bahieldin A, Bellacosa A, Bronner C, Hamiche A. MBD4 loss results in global reactivation of promoters and retroelements with low methylated CpG density. J Exp Clin Cancer Res 2023; 42:301. [PMID: 37957685 PMCID: PMC10644448 DOI: 10.1186/s13046-023-02882-z] [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: 05/17/2023] [Accepted: 11/02/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C > T transitions resulting from spontaneous deamination of 5'-methylcytosine. METHODS Here, we have investigated the potential role of MBD4 in regulating DNA methylation levels using genome-wide transcriptome and methylome analyses. Additionally, we have elucidated its function through a series of in vitro experiments. RESULTS Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. CONCLUSIONS Our data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and underscores its critical role in safeguarding against methylation damage. Furthermore, it illustrates how MBD4 functions in normal and pathological conditions.
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Affiliation(s)
- Christophe Papin
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France
| | - Abdulkhaleg Ibrahim
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France
- National Research Centre for Tropical and Transboundary Diseases (NRCTTD), Alzentan, 99316, Libya
| | - Jamal S M Sabir
- Centre of Excellence in Bionanoscience, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Stéphanie Le Gras
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France
| | - Isabelle Stoll
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France
| | - Raed S Albiheyri
- Centre of Excellence in Bionanoscience, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ali T Zari
- Centre of Excellence in Bionanoscience, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ahmed Bahieldin
- Centre of Excellence in Bionanoscience, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Alfonso Bellacosa
- Cancer Biology Program, Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Christian Bronner
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France.
| | - Ali Hamiche
- Institut de Génétique Et Biologie Moléculaire Et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe Labélisée Ligue Contre Le Cancer, 1 Rue Laurent Fries, B.P. 10142, Illkirch, 67404, Cedex, France.
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Łukasik P, Załuski M, Gutowska I. Cyclin-Dependent Kinases (CDK) and Their Role in Diseases Development-Review. Int J Mol Sci 2021; 22:ijms22062935. [PMID: 33805800 PMCID: PMC7998717 DOI: 10.3390/ijms22062935] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are involved in many crucial processes, such as cell cycle and transcription, as well as communication, metabolism, and apoptosis. The kinases are organized in a pathway to ensure that, during cell division, each cell accurately replicates its DNA, and ensure its segregation equally between the two daughter cells. Deregulation of any of the stages of the cell cycle or transcription leads to apoptosis but, if uncorrected, can result in a series of diseases, such as cancer, neurodegenerative diseases (Alzheimer’s or Parkinson’s disease), and stroke. This review presents the current state of knowledge about the characteristics of cyclin-dependent kinases as potential pharmacological targets.
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Affiliation(s)
- Paweł Łukasik
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Michał Załuski
- Department of Pharmaceutical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Izabela Gutowska
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
- Correspondence:
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Prasad R, Yen TJ, Bellacosa A. Active DNA demethylation-The epigenetic gatekeeper of development, immunity, and cancer. ADVANCED GENETICS (HOBOKEN, N.J.) 2021; 2:e10033. [PMID: 36618446 PMCID: PMC9744510 DOI: 10.1002/ggn2.10033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 01/11/2023]
Abstract
DNA methylation is a critical process in the regulation of gene expression with dramatic effects in development and continually expanding roles in oncogenesis. 5-Methylcytosine was once considered to be an inherited and stably repressive epigenetic mark, which can be only removed by passive dilution during multiple rounds of DNA replication. However, in the past two decades, physiologically controlled DNA demethylation and deamination processes have been identified, thereby revealing the function of cytosine methylation as a highly regulated and complex state-not simply a static, inherited signature or binary on-off switch. Alongside these fundamental discoveries, clinical studies over the past decade have revealed the dramatic consequences of aberrant DNA demethylation. In this review we discuss DNA demethylation and deamination in the context of 5-methylcytosine as critical processes for physiological and physiopathological transitions within three states-development, immune maturation, and oncogenic transformation; and we describe the expanding role of DNA demethylating drugs as therapeutic agents in cancer.
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Affiliation(s)
- Rahul Prasad
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Timothy J. Yen
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
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6
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Liu X, Qian D, Liu H, Abbruzzese JL, Luo S, Walsh KM, Wei Q. Genetic variants of the peroxisome proliferator-activated receptor (PPAR) signaling pathway genes and risk of pancreatic cancer. Mol Carcinog 2020; 59:930-939. [PMID: 32367578 PMCID: PMC7592725 DOI: 10.1002/mc.23208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/22/2020] [Accepted: 04/04/2020] [Indexed: 12/17/2022]
Abstract
Because the peroxisome proliferator-activated receptor (PPAR) signaling pathway is involved in development and progression of pancreatic cancer, we investigated associations between genetic variants of the PPAR pathway genes and pancreatic cancer risk by using three published genome-wide association study datasets including 8477 cases and 6946 controls of European ancestry. Expression quantitative trait loci (eQTL) analysis was also performed for correlations between genotypes of the identified genetic variants and messenger RNA (mRNA) expression levels of their genes by using available databases of the 1000 Genomes, TCGA, and GTEx projects. In the single-locus logistic regression analysis, we identified 1141 out of 17 532 significant single-nucleotide polymorphisms (SNPs) in 112 PPAR pathway genes. Further multivariate logistic regression analysis identified three independent, potentially functional loci (rs12947620 in MED1, rs11079651 in PRKCA, and rs34367566 in PRKCB) for pancreatic cancer risk (odds ratio [OR] = 1.11, 95% confidence interval [CI], [1.06-1.17], P = 5.46 × 10-5 ; OR = 1.10, 95% CI, [1.04-1.15], P = 1.99 × 10-4 ; and OR = 1.09, 95% CI, [1.04-1.14], P = 3.16 × 10-4 , respectively) among 65 SNPs that passed multiple comparison correction by false discovery rate (< 0.2). When risk genotypes of these three SNPs were combined, carriers with 2 to 3 unfavorable genotypes (NUGs) had a higher risk of pancreatic cancer than those with 0 to 1 NUGs. The eQTL analysis showed that rs34367566 A>AG was associated with decreased expression levels of PRKCB mRNA in 373 lymphoblastoid cell lines. Our findings indicate that genetic variants of the PPAR pathway genes, particularly MED1, PRKCA, and PRKCB, may contribute to susceptibility to pancreatic cancer.
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Affiliation(s)
- Xiaowen Liu
- Department of Gastric Surgery, Fudan University Shanghai Cancer Center, Shanghai 20032, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, China
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Danwen Qian
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, China
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Hongliang Liu
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - James L. Abbruzzese
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sheng Luo
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kyle M. Walsh
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Qingyi Wei
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of Medicine, Durham, NC 27710, USA
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7
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Costello R, Cantillo JF, Kenter AL. Chicken MBD4 Regulates Immunoglobulin Diversification by Somatic Hypermutation. Front Immunol 2019; 10:2540. [PMID: 31736964 PMCID: PMC6838969 DOI: 10.3389/fimmu.2019.02540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/14/2019] [Indexed: 01/21/2023] Open
Abstract
Immunoglobulin (Ig) diversification occurs via somatic hypermutation (SHM) and class switch recombination (CSR), and is initiated by activation-induced deaminase (AID), which converts cytosine to uracil. Variable (V) region genes undergo SHM to create amino acid substitutions that produce antibodies with higher affinity for antigen. The conversion of cytosine to uracil in DNA promotes mutagenesis. Two distinct DNA repair mechanisms regulate uracil processing in Ig genes. The first involves base removal by the uracil DNA glycosylase (UNG), and the second detects uracil via the mismatch repair (MMR) complex. Methyl binding domain protein 4 (MBD4) is a uracil glycosylase and an intriguing candidate for involvement in somatic hypermutation because of its interaction with the MMR MutL homolog 1 (MLH1). We found that the DNA uracil glycosylase domain of MBD4 is highly conserved among mammals, birds, shark, and insects. Conservation of the human and chicken MBD4 uracil glycosylase domain structure is striking. Here we examined the function of MBD4 in chicken DT40 B cells which undergo constitutive SHM. We constructed structural variants of MBD4 DT40 cells using CRISPR/Cas9 genome editing. Disruption of the MBD4 uracil glycosylase catalytic region increased SHM frequency in IgM loss assays. We propose that MBD4 plays a role in SHM.
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Affiliation(s)
- Ryan Costello
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
| | - Jose F Cantillo
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
| | - Amy L Kenter
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
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8
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Sannai M, Doneddu V, Giri V, Seeholzer S, Nicolas E, Yip SC, Bassi MR, Mancuso P, Cortellino S, Cigliano A, Lurie R, Ding H, Chernoff J, Sobol RW, Yen TJ, Bagella L, Bellacosa A. Modification of the base excision repair enzyme MBD4 by the small ubiquitin-like molecule SUMO1. DNA Repair (Amst) 2019; 82:102687. [PMID: 31476572 PMCID: PMC6785017 DOI: 10.1016/j.dnarep.2019.102687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/21/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
The base excision repair DNA N-glycosylase MBD4 (also known as MED1), an interactor of the DNA mismatch repair protein MLH1, plays a central role in the maintenance of genomic stability of CpG sites by removing thymine and uracil from G:T and G:U mismatches, respectively. MBD4 is also involved in DNA damage response and transcriptional regulation. The interaction with other proteins is likely critical for understanding MBD4 functions. To identify novel proteins that interact with MBD4, we used tandem affinity purification (TAP) from HEK-293 cells. The MBD4-TAP fusion and its co-associated proteins were purified sequentially on IgG and calmodulin affinity columns; the final eluate was shown to contain MLH1 by western blotting, and MBD4-associated proteins were identified by mass spectrometry. Bands with molecular weight higher than that expected for MBD4 (˜66 kD) yielded peptides corresponding to MBD4 itself and the small ubiquitin-like molecule-1 (SUMO1), suggesting that MBD4 is sumoylated in vivo. MBD4 sumoylation was validated by co-immunoprecipitation in HEK-293 and MCF7 cells, and by an in vitrosumoylation assay. Sequence and mutation analysis identified three main sumoylation sites: MBD4 is sumoylated preferentially on K137, with additional sumoylation at K215 and K377. Patterns of MBD4 sumoylation were altered, in a DNA damage-specific way, by the anti-metabolite 5-fluorouracil, the alkylating agent N-Methyl-N-nitrosourea and the crosslinking agent cisplatin. MCF7 extract expressing sumoylated MBD4 displays higher thymine glycosylase activity than the unmodified species. Of the 67 MBD4 missense mutations reported in The Cancer Genome Atlas, 14 (20.9%) map near sumoylation sites. These results indicate that MBD4 is sumoylated in vivo in a DNA damage-specific manner, and suggest that sumoylation serves to regulate its repair activity and could be compromised in cancer. This study expands the role played by sumoylation in fine-tuning DNA damage response and repair.
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Affiliation(s)
- Mara Sannai
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Valentina Doneddu
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA; Department of Biomedical Sciences, University of Sassari, Sassari, 07100, Italy
| | - Veda Giri
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Steven Seeholzer
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia PA, 19104, USA
| | - Emmanuelle Nicolas
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Shu-Chin Yip
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Maria Rosaria Bassi
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Pietro Mancuso
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Salvatore Cortellino
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Antonio Cigliano
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Rebecca Lurie
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Hua Ding
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia PA, 19104, USA
| | - Jonathan Chernoff
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Robert W Sobol
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA
| | - Timothy J Yen
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Luigi Bagella
- Department of Biomedical Sciences, University of Sassari, Sassari, 07100, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, 19122, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA.
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9
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Becker F, Joerg V, Hupe MC, Roth D, Krupar R, Lubczyk V, Kuefer R, Sailer V, Duensing S, Kirfel J, Merseburger AS, Brägelmann J, Perner S, Offermann A. Increased mediator complex subunit CDK19 expression associates with aggressive prostate cancer. Int J Cancer 2019; 146:577-588. [PMID: 31271443 DOI: 10.1002/ijc.32551] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/07/2019] [Accepted: 06/24/2019] [Indexed: 12/23/2022]
Abstract
The Mediator complex is a transcriptional regulator interacting with transcription factors and RNA-polymerase-II. Recently, we identified its subunit CDK19 to be specifically expressed in prostate cancer (PCa) and to be functionally implicated in PCa aggressiveness. Aim of our study was to comprehensively characterize the protein expression of CDK19 and its paralog CDK8 in PCa. We performed immunohistochemistry (IHC) for CDK19/CDK8 on a large cohort including needle biopsies from 202 patients, 799 primary tumor foci of radical prostatectomy specimens from 415 patients, 120 locally advanced tumor foci obtained by palliative transurethral resection, 140 lymph node metastases, 67 distant metastases and 82 benigns. Primary tumors were stained for the proliferation marker Ki67, androgen receptor (AR) and ERG. For 376 patients, clinic-pathologic data were available. Primary endpoint was disease-recurrence-free survival (DFS). Nuclear CDK19 and CDK8 expression increases during progression showing the highest intensity in metastatic and castration-resistant tumors. High CDK19 expression on primary tumors correlates with DFS independently from Gleason grade and PSA. Five-year-DFS rates of patients with primary tumors expressing no, moderate and high CDK19 are 73.7, 56.9 and 30.4%, respectively. CDK19 correlates with Gleason grade, T-stage, Ki67 proliferation-index, nuclear AR expression and ERG-status. Therapeutic options for metastatic and castration-resistant PCa remain limited. In the current study, we confirmed an important role of the Mediator subunit CDK19 in advanced PCa supporting current developments to target CDK19 and its paralog CDK8. Furthermore, CDK19 protein expression has the potential to predict disease recurrence independently from established biomarkers thus contributing to individual management for PCa patients.
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Affiliation(s)
- Finn Becker
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.,Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Vincent Joerg
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.,Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Marie C Hupe
- Department of Urology, University Hospital Schleswig-Holstein, Luebeck, Germany
| | - Doris Roth
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.,Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | | | - Verena Lubczyk
- Department of Pathology, Klinik am Eichert Alb Fils Kliniken, Goeppingen, Germany
| | - Rainer Kuefer
- Department of Urology, Klinik am Eichert Alb Fils Kliniken, Goeppingen, Germany
| | - Verena Sailer
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany
| | - Stefan Duensing
- Molecular Urooncology, Department of Urology, University of Heidelberg School of Medicine, Heidelberg, Germany
| | - Jutta Kirfel
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany
| | - Axel S Merseburger
- Department of Urology, University Hospital Schleswig-Holstein, Luebeck, Germany
| | - Johannes Brägelmann
- Molecular Pathology, Institute of Pathology, University Hospital of Cologne, Cologne, Germany.,Department of Translational Genomics, Center of Integrated Oncology Cologne-Bonn, Medical Faculty, University of Cologne, Cologne, Germany
| | - Sven Perner
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.,Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Anne Offermann
- Pathology of the University Hospital Schleswig-Holstein, Campus Luebeck, Luebeck, Germany.,Research Center Borstel, Leibniz Lung Center, Borstel, Germany
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10
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Mahmood N, Rabbani SA. DNA Methylation Readers and Cancer: Mechanistic and Therapeutic Applications. Front Oncol 2019; 9:489. [PMID: 31245293 PMCID: PMC6579900 DOI: 10.3389/fonc.2019.00489] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/23/2019] [Indexed: 12/14/2022] Open
Abstract
DNA methylation is a major epigenetic process that regulates chromatin structure which causes transcriptional activation or repression of genes in a context-dependent manner. In general, DNA methylation takes place when methyl groups are added to the appropriate bases on the genome by the action of "writer" molecules known as DNA methyltransferases. How these methylation marks are read and interpreted into different functionalities represents one of the main mechanisms through which the genes are switched "ON" or "OFF" and typically involves different types of "reader" proteins that can recognize and bind to the methylated regions. A tightly balanced regulation exists between the "writers" and "readers" in order to mediate normal cellular functions. However, alterations in normal methylation pattern is a typical hallmark of cancer which alters the way methylation marks are written, read and interpreted in different disease states. This unique characteristic of DNA methylation "readers" has identified them as attractive therapeutic targets. In this review, we describe the current state of knowledge on the different classes of DNA methylation "readers" identified thus far along with their normal biological functions, describe how they are dysregulated in cancer, and discuss the various anti-cancer therapies that are currently being developed and evaluated for targeting these proteins.
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Affiliation(s)
- Niaz Mahmood
- Department of Medicine, McGill University Health Centre, Montréal, QC, Canada
| | - Shafaat A Rabbani
- Department of Medicine, McGill University Health Centre, Montréal, QC, Canada
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11
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Liu HC, Zeng J, Zhang B, Liu XQ, Dai M. Inhibitory effect of MSH6 gene silencing in combination with cisplatin on cell proliferation of human osteosarcoma cell line MG63. J Cell Physiol 2018; 234:9358-9369. [PMID: 30456894 DOI: 10.1002/jcp.27620] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/25/2018] [Indexed: 12/23/2022]
Abstract
Osteosarcoma (OS) is one of the most common primary bone malignancies, with the survival rate of patients with OS remaining low. Therefore, we conducted this study to identify the potential role combination of both MSH6 gene silencing and cisplatin (DDP) plays in OS cell proliferation and apoptosis. Microarray-based gene expression profiling was used to identify the differentially expressed genes (DEGs) in patients with OS, as well as microRNAs (miRNAs) that regulate the candidate gene. OS tissues from 67 patients with OS along with normal tissues from 24 amputee patients were collected for detection of the positive expression of mutS homolog 6 (MSH6) protein, mRNA, and protein expressions of c-myc, cyclin D1, l-2, B-cell lymphoma 2 (Bcl-2), Stathmin, proliferating cell nuclear antigen (PCNA), and Bcl-2-associated X (Bax). Moreover, after MSH6 silencing and DDP were treated on the selected human OS cell line MG63 with the highest expression of MSH6, cell viability, cell cycle distribution, and apoptosis were detected. The microarray analysis showed that MSH6 was upregulated in OS chip data. Furthermore, silencing MSH6 combined with DDP reduced expressions of c-myc, cyclin D1, Bcl-2, Stathmin, and PCNA, and elevated Bax expression, whereas inhibiting OS cell viability, impeding cell cycle distribution, and inducing apoptosis. In conclusion, our preliminary results indicated that the combination of MSH6 gene silencing coupled with DDP may have a better effect on the inhibition of OS cell proliferation and promote apoptosis, potentially providing targets for the OS treatment.
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Affiliation(s)
- Hu-Cheng Liu
- Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jin Zeng
- Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Bin Zhang
- Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xu-Qiang Liu
- Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Min Dai
- Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
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12
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Sanders MA, Chew E, Flensburg C, Zeilemaker A, Miller SE, Al Hinai AS, Bajel A, Luiken B, Rijken M, Mclennan T, Hoogenboezem RM, Kavelaars FG, Fröhling S, Blewitt ME, Bindels EM, Alexander WS, Löwenberg B, Roberts AW, Valk PJM, Majewski IJ. MBD4 guards against methylation damage and germ line deficiency predisposes to clonal hematopoiesis and early-onset AML. Blood 2018; 132:1526-1534. [PMID: 30049810 PMCID: PMC6172562 DOI: 10.1182/blood-2018-05-852566] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023] Open
Abstract
The tendency of 5-methylcytosine (5mC) to undergo spontaneous deamination has had a major role in shaping the human genome, and this methylation damage remains the primary source of somatic mutations that accumulate with age. How 5mC deamination contributes to cancer risk in different tissues remains unclear. Genomic profiling of 3 early-onset acute myeloid leukemias (AMLs) identified germ line loss of MBD4 as an initiator of 5mC-dependent hypermutation. MBD4-deficient AMLs display a 33-fold higher mutation burden than AML generally, with >95% being C>T in the context of a CG dinucleotide. This distinctive signature was also observed in sporadic cancers that acquired biallelic mutations in MBD4 and in Mbd4 knockout mice. Sequential sampling of germ line cases demonstrated repeated expansion of blood cell progenitors with pathogenic mutations in DNMT3A, a key driver gene for both clonal hematopoiesis and AML. Our findings reveal genetic and epigenetic factors that shape the mutagenic influence of 5mC. Within blood cells, this links methylation damage to the driver landscape of clonal hematopoiesis and reveals a conserved path to leukemia. Germ line MBD4 deficiency enhances cancer susceptibility and predisposes to AML.
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Affiliation(s)
- Mathijs A Sanders
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Edward Chew
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Clinical Hematology, Peter MacCallum Cancer Center, Royal Melbourne Hospital, Parkville, VIC, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
- Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
| | - Christoffer Flensburg
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Annelieke Zeilemaker
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Sarah E Miller
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Adil S Al Hinai
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
- National Genetic Center, Royal Hospital, Ministry of Health, Muscat, Sultanate of Oman
| | - Ashish Bajel
- Clinical Hematology, Peter MacCallum Cancer Center, Royal Melbourne Hospital, Parkville, VIC, Australia
- Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
| | - Bram Luiken
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Melissa Rijken
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Tamara Mclennan
- Division of Molecular Medicine, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Remco M Hoogenboezem
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - François G Kavelaars
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Stefan Fröhling
- Division of Translational Oncology, National Center for Tumor Diseases Heidelberg and German Cancer Research Center, Heidelberg, Germany
- German Cancer Consortium, Heidelberg, Germany; and
- Section for Personalized Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Marnie E Blewitt
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
- Division of Molecular Medicine, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Eric M Bindels
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Warren S Alexander
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Bob Löwenberg
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Andrew W Roberts
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Clinical Hematology, Peter MacCallum Cancer Center, Royal Melbourne Hospital, Parkville, VIC, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
- Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
| | - Peter J M Valk
- Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Ian J Majewski
- Division of Cancer and Haematology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
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13
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Yu AM, Calvo JA, Muthupalani S, Samson LD. The Mbd4 DNA glycosylase protects mice from inflammation-driven colon cancer and tissue injury. Oncotarget 2017; 7:28624-36. [PMID: 27086921 PMCID: PMC5053750 DOI: 10.18632/oncotarget.8721] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/28/2016] [Indexed: 12/12/2022] Open
Abstract
Much of the global cancer burden is associated with longstanding inflammation accompanied by release of DNA-damaging reactive oxygen and nitrogen species. Here, we report that the Mbd4 DNA glycosylase is protective in the azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model of inflammation-driven colon cancer. Mbd4 excises T and U from T:G and U:G mismatches caused by deamination of 5-methylcytosine and cytosine. Since the rate of deamination is higher in inflamed tissues, we investigated the role of Mbd4 in inflammation-driven tumorigenesis. In the AOM/DSS assay, Mbd4-/- mice displayed more severe clinical symptoms, decreased survival, and a greater tumor burden than wild-type (WT) controls. The increased tumor burden in Mbd4-/- mice did not arise from impairment of AOM-induced apoptosis in the intestinal crypt. Histopathological analysis indicated that the colonic epithelium of Mbd4-/- mice is more vulnerable than WT to DSS-induced tissue damage. We investigated the role of the Mbd4-/- immune system in AOM/DSS-mediated carcinogenesis by repeating the assay on WT and Mbd4-/- mice transplanted with WT bone marrow. Mbd4-/- mice with WT bone marrow behaved similarly to Mbd4-/- mice. Together, our results indicate that the colonic epithelium of Mbd4-/- mice is more vulnerable to DSS-induced injury, which exacerbates inflammation-driven tissue injury and cancer.
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Affiliation(s)
- Amy Marie Yu
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Jennifer A Calvo
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Suresh Muthupalani
- Department of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Leona D Samson
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
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14
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Suzuki S, Iwaizumi M, Yamada H, Sugiyama T, Hamaya Y, Furuta T, Kanaoka S, Sugimura H, Miyajima H, Osawa S, Carethers JM, Sugimoto K. MBD4 frameshift mutation caused by DNA mismatch repair deficiency enhances cytotoxicity by trifluridine, an active antitumor agent of TAS-102, in colorectal cancer cells. Oncotarget 2017; 9:11477-11488. [PMID: 29545913 PMCID: PMC5837757 DOI: 10.18632/oncotarget.22484] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 10/02/2017] [Indexed: 01/12/2023] Open
Abstract
Backgrounds Trifluridine is an active antitumor component of TAS-102 that resembles 5-fluorouracil. Although patients with advanced colorectal cancer (CRC) exhibiting a mismatch repair (MMR) deficiency reportedly do not benefit from 5-fluorouracil-based chemotherapy and we previously reported that truncated methyl-CpG binding domain protein 4 (MBD4) enhances 5-fluorouracil cytotoxicity in MMR-deficient CRC cells, little is known regarding the effect of MMR deficiency on trifluridine cytotoxicity in CRC. Aim We investigated whether trifluridine induces cytotoxicity in a DNA MMR-dependent manner and evaluated how truncated MBD4 alters trifluridine cytotoxicity. Methods We utilized the human CRC cell lines HCT116 (hMLH1-deficient cells) and HCT116+ch3 (hMLH1-restored cells) and compared their sensitivities to trifluridine. And we established 5-fluorouracil-refractory hMLH1-deficient cells and analyzed trifluridine cytotoxicity. Finally, we established truncated MBD4 overexpressed CRC cell lines, and compared trifluridine sensitivity.
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Affiliation(s)
- Satoshi Suzuki
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Moriya Iwaizumi
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hidetaka Yamada
- Department of Tumor Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tomohiro Sugiyama
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasushi Hamaya
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Takahisa Furuta
- Center for Clinical Research, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Shigeru Kanaoka
- Department of Gastroenterology, Hamamatsu Medical Center, Hamamatsu, Japan
| | - Haruhiko Sugimura
- Department of Tumor Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan.,International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hiroaki Miyajima
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Satoshi Osawa
- Department of Endoscopic and Photodynamic Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - John M Carethers
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Ken Sugimoto
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
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15
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Poulos RC, Olivier J, Wong JWH. The interaction between cytosine methylation and processes of DNA replication and repair shape the mutational landscape of cancer genomes. Nucleic Acids Res 2017; 45:7786-7795. [PMID: 28531315 PMCID: PMC5737810 DOI: 10.1093/nar/gkx463] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/15/2017] [Indexed: 12/31/2022] Open
Abstract
Methylated cytosines (5mCs) are frequently mutated in the genome. However, no studies have yet comprehensively analysed mutation–methylation associations across cancer types. Here we analyse 916 cancer genomes, together with tissue type-specific methylation and replication timing data. We describe a strong mutation–methylation association across colorectal cancer subtypes, most interestingly in samples with microsatellite instability (MSI) or Polymerase epsilon (POLE) exonuclease domain mutations. By analysing genomic regions with differential mismatch repair (MMR) efficiency, we suggest a possible role for MMR in the correction of 5mC deamination events, potentially accounting for the high rate of 5mC mutation accumulation in MSI tumours. Additionally, we propose that mutant POLE asserts a mutator phenotype specifically at 5mCs, and we find coding mutation hotspots in POLE-mutant cancers at highly-methylated CpGs in the tumour-suppressor genes APC and TP53. Finally, using multivariable regression models, we demonstrate that different cancers exhibit distinct mutation–methylation associations, with DNA repair influencing such associations in certain cancer genomes. Taken together, we find differential associations with methylation that are vital for accurately predicting expected mutation loads across cancer types. Our findings reveal links between methylation and common mutation and repair processes, with these mechanisms defining a key part of the mutational landscape of cancer genomes.
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Affiliation(s)
- Rebecca C Poulos
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Sydney, NSW 2052, Australia
| | - Jake Olivier
- School of Mathematics and Statistics, The Red Centre, UNSW Sydney, NSW 2052, Australia
| | - Jason W H Wong
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Sydney, NSW 2052, Australia
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16
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Moon BS, Yun HM, Chang WH, Steele BH, Cai M, Choi SH, Lu W. Smek promotes corticogenesis through regulating Mbd3's stability and Mbd3/NuRD complex recruitment to genes associated with neurogenesis. PLoS Biol 2017; 15:e2001220. [PMID: 28467410 PMCID: PMC5414985 DOI: 10.1371/journal.pbio.2001220] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 04/06/2017] [Indexed: 11/18/2022] Open
Abstract
The fate of neural progenitor cells (NPCs) during corticogenesis is determined by a complex interplay of genetic or epigenetic components, but the underlying mechanism is incompletely understood. Here, we demonstrate that Suppressor of Mek null (Smek) interact with methyl-CpG-binding domain 3 (Mbd3) and the complex plays a critical role in self-renewal and neuronal differentiation of NPCs. We found that Smek promotes Mbd3 polyubiquitylation and degradation, blocking recruitment of the repressive Mbd3/nucleosome remodeling and deacetylase (NuRD) complex at the neurogenesis-associated gene loci, and, as a consequence, increasing acetyl histone H3 activity and cortical neurogenesis. Furthermore, overexpression of Mbd3 significantly blocked neuronal differentiation of NPCs, and Mbd3 depletion rescued neurogenesis defects seen in Smek1/2 knockout mice. These results reveal a novel molecular mechanism underlying Smek/Mbd3/NuRD axis-mediated control of NPCs' self-renewal and neuronal differentiation during mammalian corticogenesis.
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Affiliation(s)
- Byoung-San Moon
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Hyung-Mun Yun
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Wen-Hsuan Chang
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Bradford H. Steele
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Mingyang Cai
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Si Ho Choi
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Wange Lu
- Broad Center for Regenerative Medicine and Stem Cell Research, Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
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17
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Wang X, Dong C, Yin J, Tang W, Shen Z. Tagging polymorphisms of methyl-CpG binding domain 4 and gastric cardiac adenocarcinoma risk in a Chinese population. Dis Esophagus 2017; 30:1-6. [PMID: 27868291 DOI: 10.1111/dote.12500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Potential effects of genetic factors on carcinogenesis of gastric cardiac adenocarcinoma (GCA) may exist. The present experiment specifically evaluated the genetic influence of single nucleotide in methyl-CpG binding domain 4 (MBD4) on GCA tumorigenesis. A case-control experiment based on hospital recruited 330 GCA patients and 608 non-cancer patients was carried out. We employed ligation detection reaction method to detect the genotypes. The results revealed that MBD4 rs3138373, rs2005618, and rs3138355 mutations had no significant association with the risk of GCA. However, a lower risk of GCA presented in male patients who carried the MBD4 rs3138355 G>A polymorphic loci by the stratified analyses. In general, The MBD4 gene polymorphism could not influence GCA hereditary predisposition. Nevertheless, whether the finding learned from our experiment could apply to other ethnic groups will remain vague until future multicenter studies further test and verify our conclusions.
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Affiliation(s)
- Xu Wang
- Department of Cardiovascular Surgery of the First Affiliated Hospital, Institute for Cardiovascular Science of Soochow University, Soochow
| | - Changqing Dong
- Department of Cardiovascular Surgery of the First Affiliated Hospital, Institute for Cardiovascular Science of Soochow University, Soochow
| | - Jun Yin
- Department of Cardiothoracic Surgery of Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Weifeng Tang
- Department of Cardiothoracic Surgery of Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Zhenya Shen
- Department of Cardiovascular Surgery of the First Affiliated Hospital, Institute for Cardiovascular Science of Soochow University, Soochow
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18
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Involvement of MBD4 inactivation in mismatch repair-deficient tumorigenesis. Oncotarget 2016; 6:42892-904. [PMID: 26503472 PMCID: PMC4767479 DOI: 10.18632/oncotarget.5740] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/18/2015] [Indexed: 12/14/2022] Open
Abstract
The DNA glycosylase gene MBD4 safeguards genomic stability at CpG sites and is frequently mutated at coding poly-A tracks in mismatch repair (MMR)-defective colorectal tumors (CRC). Mbd4 biallelic inactivation in mice provided conflicting results as to its role in tumorigenesis. Thus, it is unclear whether MBD4 alterations are only secondary to MMR defects without functional consequences or can contribute to the mutator phenotype. We investigated MBD4 variants in a large series of hereditary/familial and sporadic CRC cases. Whereas MBD4 frameshifts were only detected in tumors, missense variants were found in both normal and tumor DNA. In CRC with double-MBD4/MMR and single-MBD4 variants, transition mutation frequency was increased, indicating that MBD4 defects may affect the mutational landscape independently of MMR defect. Mbd4-deficient mice showed reduced survival when combined with Mlh1−/− genotype. Taken together, these data suggest that MBD4 inactivation may contribute to tumorigenesis, acting as a modifier of MMR-deficient cancer phenotype.
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19
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Suzuki S, Iwaizumi M, Tseng-Rogenski S, Hamaya Y, Miyajima H, Kanaoka S, Sugimoto K, Carethers JM. Production of truncated MBD4 protein by frameshift mutation in DNA mismatch repair-deficient cells enhances 5-fluorouracil sensitivity that is independent of hMLH1 status. Cancer Biol Ther 2016; 17:760-8. [PMID: 27115207 PMCID: PMC4970528 DOI: 10.1080/15384047.2016.1178430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 01/12/2023] Open
Abstract
Methyl-CpG binding domain protein 4 (MBD4) is a DNA glycosylase that can remove 5-fluorodeoxyuracil from DNA as well as repair T:G or U:G mismatches. MBD4 is a target for frameshift mutation with DNA mismatch repair (MMR) deficiency, creating a truncated MBD4 protein (TruMBD4) that lacks its glycosylase domain. Here we show that TruMBD4 plays an important role for enhancing 5-fluorouracil (5FU) sensitivity in MMR-deficient colorectal cancer cells. We found biochemically that TruMBD4 binds to 5FU incorporated into DNA with higher affinity than MBD4. TruMBD4 reduced the 5FU affinity of the MMR recognition complexes that determined 5FU sensitivity by previous reports, suggesting other mechanisms might be operative to trigger cytotoxicity. To analyze overall 5FU sensitivity with TruMBD4, we established TruMBD4 overexpression in hMLH1-proficient or -deficient colorectal cancer cells followed by treatment with 5FU. 5FU-treated TruMBD4 cells demonstrated diminished growth characteristics compared to controls, independently of hMLH1 status. Flow cytometry revealed more 5FU-treated TruMBD4 cells in S phase than controls. We conclude that patients with MMR-deficient cancers, which show characteristic resistance to 5FU therapy, may be increased for 5FU sensitivity via secondary frameshift mutation of the base excision repair gene MBD4.
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Affiliation(s)
- Satoshi Suzuki
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Moriya Iwaizumi
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
- Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MA, USA
| | - Stephanie Tseng-Rogenski
- Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MA, USA
| | - Yasushi Hamaya
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
- Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MA, USA
| | - Hiroaki Miyajima
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Shigeru Kanaoka
- Department of Gastroenterology, Hamamatsu Medical Center, Shizuoka, Japan
| | - Ken Sugimoto
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - John M. Carethers
- Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MA, USA
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20
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Ludwig AK, Zhang P, Cardoso MC. Modifiers and Readers of DNA Modifications and Their Impact on Genome Structure, Expression, and Stability in Disease. Front Genet 2016; 7:115. [PMID: 27446199 PMCID: PMC4914596 DOI: 10.3389/fgene.2016.00115] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/06/2016] [Indexed: 12/16/2022] Open
Abstract
Cytosine base modifications in mammals underwent a recent expansion with the addition of several naturally occurring further modifications of methylcytosine in the last years. This expansion was accompanied by the identification of the respective enzymes and proteins reading and translating the different modifications into chromatin higher order organization as well as genome activity and stability, leading to the hypothesis of a cytosine code. Here, we summarize the current state-of-the-art on DNA modifications, the enzyme families setting the cytosine modifications and the protein families reading and translating the different modifications with emphasis on the mouse protein homologs. Throughout this review, we focus on functional and mechanistic studies performed on mammalian cells, corresponding mouse models and associated human diseases.
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Affiliation(s)
- Anne K Ludwig
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - M C Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
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Meng H, Harrison DJ, Meehan RR. MBD4 interacts with and recruits USP7 to heterochromatic foci. J Cell Biochem 2015; 116:476-85. [PMID: 25358258 PMCID: PMC4964934 DOI: 10.1002/jcb.25001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/23/2014] [Indexed: 12/19/2022]
Abstract
MBD4 is the only methyl‐CpG binding protein that possesses a C‐terminal glycosylase domain. It has been associated with a number of nuclear pathways including DNA repair, DNA damage response, the initiation of apoptosis, transcriptional repression, and DNA demethylation. However, the precise contribution of MBD4 to these processes in development and relevant diseases remains elusive. We identified UHRF1 and USP7 as two new interaction partners for MBD4. Both UHRF1, a E3 ubiquitin ligase, and USP7, a de‐ubiquinating enzyme, regulate the stability of the DNA maintenance methyltransferase, Dnmt1. The ability of MBD4 to directly interact with and recruit USP7 to chromocenters implicates it as an additional factor that can potentially regulate Dnmt1 activity during cell proliferation. J. Cell. Biochem. 116: 476–485, 2015. © 2014 The Authors. Journal of Cellular Biochemistry published by Wiley Periodicals, Inc.
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Affiliation(s)
- Huan Meng
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
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Du Q, Luu PL, Stirzaker C, Clark SJ. Methyl-CpG-binding domain proteins: readers of the epigenome. Epigenomics 2015; 7:1051-73. [DOI: 10.2217/epi.15.39] [Citation(s) in RCA: 265] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How DNA methylation is interpreted and influences genome regulation remains largely unknown. Proteins of the methyl-CpG-binding domain (MBD) family are primary candidates for the readout of DNA methylation as they recruit chromatin remodelers, histone deacetylases and methylases to methylated DNA associated with gene repression. MBD protein binding requires both functional MBD domains and methyl-CpGs; however, some MBD proteins also bind unmethylated DNA and active regulatory regions via alternative regulatory domains or interaction with the nucleosome remodeling deacetylase (NuRD/Mi-2) complex members. Mutations within MBD domains occur in many diseases, including neurological disorders and cancers, leading to loss of MBD binding specificity to methylated sites and gene deregulation. Here, we summarize the current state of knowledge about MBD proteins and their role as readers of the epigenome.
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Affiliation(s)
- Qian Du
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Phuc-Loi Luu
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Clare Stirzaker
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
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Bellacosa A, Drohat AC. Role of base excision repair in maintaining the genetic and epigenetic integrity of CpG sites. DNA Repair (Amst) 2015; 32:33-42. [PMID: 26021671 DOI: 10.1016/j.dnarep.2015.04.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytosine methylation at CpG dinucleotides is a central component of epigenetic regulation in vertebrates, and the base excision repair (BER) pathway is important for maintaining both the genetic stability and the methylation status of CpG sites. This perspective focuses on two enzymes that are of particular importance for the genetic and epigenetic integrity of CpG sites, methyl binding domain 4 (MBD4) and thymine DNA glycosylase (TDG). We discuss their capacity for countering C to T mutations at CpG sites, by initiating base excision repair of G · T mismatches generated by deamination of 5-methylcytosine (5mC). We also consider their role in active DNA demethylation, including pathways that are initiated by oxidation and/or deamination of 5mC.
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Affiliation(s)
- Alfonso Bellacosa
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, United States.
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD 21201, United States.
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Kim JH, Kang GH. Molecular and prognostic heterogeneity of microsatellite-unstable colorectal cancer. World J Gastroenterol 2014; 20:4230-4243. [PMID: 24764661 PMCID: PMC3989959 DOI: 10.3748/wjg.v20.i15.4230] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 01/30/2014] [Accepted: 02/20/2014] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancers (CRCs) with a high level of microsatellite instability (MSI-H) are clinicopathologically distinct tumors characterized by predominance in females, proximal colonic localization, poor differentiation, mucinous histology, tumor-infiltrating lymphocytes, a Crohn’s-like lymphoid reaction and a favorable prognosis. In terms of their molecular features, MSI-H CRCs are heterogeneous tumors associated with various genetic and epigenetic alterations, including DNA mismatch repair deficiency, target microsatellite mutations, BRAF mutations, a CpG island methylator phenotype-high (CIMP-H) status, and a low level of genomic hypomethylation. The molecular heterogeneity of MSI-H CRCs also depends on ethnic differences; for example, in Eastern Asian countries, relatively low frequencies of CIMP-H and BRAF mutations have been observed in MSI-H CRCs compared to Western countries. Although the prognostic features of MSI-H CRCs include a favorable survival of patients and low benefit of adjuvant chemotherapy, there may be prognostic differences based on the molecular heterogeneity of MSI-H CRCs. Here, we have reviewed and discussed the molecular and prognostic features of MSI-H CRCs, as well as several putative prognostic or predictive molecular markers, including HSP110 expression, beta2-microglobulin mutations, myosin 1a expression, CDX2/CK20 expression, SMAD4 expression, CIMP status and LINE-1 methylation levels.
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Wyatt MD. Advances in understanding the coupling of DNA base modifying enzymes to processes involving base excision repair. Adv Cancer Res 2014; 119:63-106. [PMID: 23870509 DOI: 10.1016/b978-0-12-407190-2.00002-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This chapter describes some of the recent, exciting developments that have characterized and connected processes that modify DNA bases with DNA repair pathways. It begins with AID/APOBEC or TET family members that covalently modify bases within DNA. The modified bases, such as uracil or 5-formylcytosine, are then excised by DNA glycosylases including UNG or TDG to initiate base excision repair (BER). BER is known to preserve genome integrity by removing damaged bases. The newer studies underscore the necessity of BER following enzymes that deliberately damage DNA. This includes the role of BER in antibody diversification and more recently, its requirement for demethylation of 5-methylcytosine in mammalian cells. The recent advances have shed light on mechanisms of DNA demethylation, and have raised many more questions. The potential hazards of these processes have also been revealed. Dysregulation of the activity of base modifying enzymes, and resolution by unfaithful or corrupt means can be a driver of genome instability and tumorigenesis. The understanding of both DNA and histone methylation and demethylation is now revealing the true extent to which epigenetics influence normal development and cancer, an abnormal development.
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Affiliation(s)
- Michael D Wyatt
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, USA.
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26
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Bardhan K, Liu K. Epigenetics and colorectal cancer pathogenesis. Cancers (Basel) 2013; 5:676-713. [PMID: 24216997 PMCID: PMC3730326 DOI: 10.3390/cancers5020676] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/22/2013] [Accepted: 05/24/2013] [Indexed: 12/13/2022] Open
Abstract
Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.
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Affiliation(s)
- Kankana Bardhan
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, and Cancer Center, Georgia Regents University, Augusta, GA 30912, USA.
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The MBD4 Glu346Lys polymorphism is associated with the risk of cervical cancer in a Chinese population. Int J Gynecol Cancer 2013; 22:1552-6. [PMID: 23027038 DOI: 10.1097/igc.0b013e31826e22e4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Methyl-CpG binding domain 4 (MBD4) protein functions as a DNA repair enzyme and plays an important role in maintaining genome integrity and carcinogenesis. The polymorphisms in the MBD4 gene may be associated with differences in DNA repair capacity and thereby influence an individual's susceptibility to cervical cancer. To verify this hypothesis, we examined the potential association between the MBD4 Glu346Lys polymorphism (rs140693, G>A) and the risk of cervical cancer in a Chinese population. METHODS We genotyped the MBD4 Glu346Lys polymorphism in 146 cervical cancer cases and 320 healthy female subjects using polymerase chain reaction-based restriction fragment length polymorphism method. Unconditional logistic regression analysis was used to estimate the association between the genotypes and the risk of cervical cancer. RESULTS We observed a significantly decreased risk of cervical cancer associated with the heterozygous Lys/Glu genotype (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.36-0.99; P = 0.046) and the homozygous Glu/Glu genotype (OR, 0.52; 95% CI, 0.30-0.89; P = 0.018), compared with the Lys/Lys homozygotes. Moreover, the reduced cervical cancer risk was more predominant among younger subjects or human papillomavirus-positive individuals carrying Glu/Glu genotypes (OR, 0.33; 95% CI, 0.14-0.78, P = 0.011; and OR, 0.27; 95% CI, 0.09-0.75, P = 0.013, respectively). CONCLUSIONS The MBD4 codon 346 polymorphism may play a role in cervical cancer susceptibility in the Chinese population. Further larger case-control and functional studies are needed to validate these findings.
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LI W, LIN Y. Identification of Human Methyl-CpG Binding Domain Protein (MBD) 4 as a Substrate of Protein Kinase X*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The base excision repair system is vital to the repair of endogenous and exogenous DNA damage. This pathway is initiated by one of several DNA glycosylases that recognizes and excises specific DNA lesions in a coordinated fashion. Methyl-CpG Domain Protein 4 (MBD4) and Thymine DNA Glycosylase (TDG) are the two major G:T glycosylases that remove thymine generated by the deamination of 5-methylcytosine. Both of these glycosylases also remove a variety of other base lesions, including G:U and preferentially act at CpG sites throughout the genome. Many have questioned the purpose of seemingly redundant glycosylases, but new information has emerged to suggest MBD4 and TDG have diverse biological functions. MBD4 has been closely linked to apoptosis, while TDG has been clearly implicated in transcriptional regulation. This article reviews all of these developments, and discusses the consequences of germline and somatic mutations that lead to non-synonymous amino acid substitutions on MBD4 and TDG protein function. In addition, we report the finding of alternatively spliced variants of MBD4 and TDG and the results of functional studies of a tumor-associated variant of MBD4.
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Spisák S, Kalmár A, Galamb O, Wichmann B, Sipos F, Péterfia B, Csabai I, Kovalszky I, Semsey S, Tulassay Z, Molnár B. Genome-wide screening of genes regulated by DNA methylation in colon cancer development. PLoS One 2012; 7:e46215. [PMID: 23049694 PMCID: PMC3462205 DOI: 10.1371/journal.pone.0046215] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 08/28/2012] [Indexed: 02/05/2023] Open
Abstract
Tumorigenesis is accompanied by changes in the DNA methylation pattern. Our aim was to test a novel approach for identification of transcripts at whole transcript level which are regulated by DNA methylation. Our approach is based on comparison of data obtained from transcriptome profiling of primary human samples and in vitro cell culture models. Epithelial cells were collected by LCM from normal, adenoma, and tumorous colonic samples. Using gene expression analysis, we identified downregulated genes in the tumors compared to normal tissues. In parallel 3000 upregulated genes were determined in HT-29 colon adenocarcinoma cell culture model after DNA demethylation treatment. Of the 2533 transcripts showing reduced expression in the tumorous samples, 154 had increased expression as a result of DNA demethylation treatment. Approximately 2/3 of these genes had decreased expression already in the adenoma samples. Expression of five genes (GCG, NMES-1, LRMP, FAM161B and PTGDR), was validated using RT-PCR. PTGDR showed ambiguous results, therefore it was further studied to verify the extent of DNA methylation and its effect on the protein level. Results confirmed that our approach is suitable for genome-wide screening of genes which are regulated or inactivated by DNA methylation. Activity of these genes possibly interferes with tumor progression, therefore genes identified can be key factors in the formation and in the progression of the disease.
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Affiliation(s)
- Sándor Spisák
- Molecular Medicine Research Unit, Hungarian Academy of Sciences, Budapest, Hungary.
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31
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Abstract
The methyl-CpG binding proteins (MBPs) interpret the methylation of DNA and its components. The number of MBPs in the human body currently stands at 15, which are split into 3 branches, a reflection of the intricate mechanisms of gene regulation. Each branch utilizes a different mechanism for interacting with methylated DNA or its components. These interactions function to direct gene expression and maintain or alter DNA architecture. It is these functions that are commonly exploited in human disease. For this review, we will focus on each protein and any roles it may have in initiating, promoting, progressing, or inhibiting cancer. This will highlight common threads in the roles of these proteins, which will allow us to speculate on potentially productive directions for future research.
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Affiliation(s)
- Lee Parry
- School of Biosciences, Cardiff University, Cardiff, UK
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32
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Flanking nucleotide specificity for DNA mismatch repair-deficient frameshifts within activin receptor 2 (ACVR2). Mutat Res 2011; 729:73-80. [PMID: 22001236 DOI: 10.1016/j.mrfmmm.2011.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/27/2011] [Indexed: 11/23/2022]
Abstract
We previously demonstrated that exonic selectivity for frameshift mutation (exon 10 over exon 3) of ACVR2 in mismatch repair (MMR)-deficient cells is partially determined by 6 nucleotides flanking 5' and 3' of each microsatellite. Substitution of flanking nucleotides surrounding the exon 10 microsatellite with those surrounding the exon 3 microsatellite greatly diminished heteroduplex (A(7)/T(8)) and full (A(7)/T(7)) mutation, while substitution of flanking nucleotides from exon 3 with those from exon 10 enhanced frameshift mutation. We hypothesized that specific individual nucleotide(s) within these flanking sequences control ACVR2 frameshift mutation rates. Only the 3rd nucleotide 5' of the microsatellite, and 3rd, 4th, and 5th nucleotides 3' of the microsatellite were altered from the native flanking sequences and these locations were individually altered (sites A, B, C, and D, respectively). Constructs were cloned +1bp out-of-frame of EGFP, allowing a -1bp frameshift to express EGFP. Plasmids were stably transfected into MMR-deficient cells. Non-fluorescent cells were sorted, cultured for 35 days, and harvested for flow cytometry and DNA-sequencing. Site A (C to T) and B (G to C) in ACVR2 exon 10 decreased both heteroduplex and full mutant as much as the construct containing all 4 alterations. For ACVR2 exon 3, site A (T to C), C (A to G), and D (G to C) are responsible for increased heteroduplex formation, whereas site D is responsible for full mutant formation by ACVR2 exon 10 flanking sequences. Exonic selectivity for frameshift mutation within ACVR2's sequence context is specifically controlled by individual nucleotides flanking each microsatellite.
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Zaanan A, Meunier K, Sangar F, Fléjou JF, Praz F. Microsatellite instability in colorectal cancer: from molecular oncogenic mechanisms to clinical implications. Cell Oncol (Dordr) 2011; 34:155-76. [PMID: 21484480 DOI: 10.1007/s13402-011-0024-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2011] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Microsatellite instability (MSI) constitutes an important oncogenic molecular pathway in colorectal cancer (CRC), representing approximately 15% of all colorectal malignant tumours. In roughly one third of the cases, the underlying DNA mismatch repair (MMR) defect is inherited through the transmission of a mutation in one of the genes involved in MMR, predominantly MSH2 and MLH1, or less frequently, MSH6 or PMS2. In the overwhelming number of sporadic cases, MSI results from epigenetic MLH1 silencing through hypermethylation of its promoter. MMR deficiency promotes colorectal oncogenesis through the accumulation of numerous mutations in crucial target genes harbouring mononucleotide repeats, notably in those involved in the control of cell proliferation and differentiation, as well as DNA damage signalling and repair. DESIGN In this review, we describe the molecular aspects of the MMR system and the biological consequences of its defect on the oncogenic process, and we discuss the various experimental systems used to evaluate the efficacy of cytotoxic drugs on MSI colorectal cells lines. There is increasing evidence showing that MSI CRCs differ from all CRCs in terms of prognosis and response to the treatment. We report the clinical studies that have evaluated the prognostic and predictive value of MSI status on clinical outcome in patients treated with various chemotherapy regimens used in the adjuvant setting or for advanced CRCs. CONCLUSION In view of this, the opportunity of a systematic MSI phenotyping in the clinical management of patients with CRC is further discussed.
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Affiliation(s)
- Aziz Zaanan
- INSERM, UMR_S, Centre de Recherche Saint-Antoine, Paris, France
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Meng HX, Hackett JA, Nestor C, Dunican DS, Madej M, Reddington JP, Pennings S, Harrison DJ, Meehan RR. Apoptosis and DNA methylation. Cancers (Basel) 2011; 3:1798-820. [PMID: 24212783 PMCID: PMC3757391 DOI: 10.3390/cancers3021798] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 03/11/2011] [Accepted: 03/11/2011] [Indexed: 01/05/2023] Open
Abstract
Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.
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Affiliation(s)
- Huan X. Meng
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
| | - James A. Hackett
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
| | - Colm Nestor
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
- Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mail: (D.J.H.)
| | - Donncha S. Dunican
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
| | - Monika Madej
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
| | - James P. Reddington
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
| | - Sari Pennings
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK; E-Mail: (S.P.)
| | - David J. Harrison
- Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mail: (D.J.H.)
| | - Richard R. Meehan
- MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mails: (H.X.M.); (J.A.H.); (C.N.); (D.S.D.); (M.M.); (J.P.R.)
- Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK; E-Mail: (D.J.H.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44 (0)-332-2471; Fax: +44 (0) 131 467 8456
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Bignell GR, Greenman CD, Davies H, Butler AP, Edkins S, Andrews JM, Buck G, Chen L, Beare D, Latimer C, Widaa S, Hinton J, Fahey C, Fu B, Swamy S, Dalgliesh GL, Teh BT, Deloukas P, Yang F, Campbell PJ, Futreal PA, Stratton MR. Signatures of mutation and selection in the cancer genome. Nature 2010; 463:893-8. [PMID: 20164919 PMCID: PMC3145113 DOI: 10.1038/nature08768] [Citation(s) in RCA: 542] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 12/14/2009] [Indexed: 02/06/2023]
Abstract
The cancer genome is moulded by the dual processes of somatic mutation and selection. Homozygous deletions in cancer genomes occur over recessive cancer genes, where they can confer selective growth advantage, and over fragile sites, where they are thought to reflect an increased local rate of DNA breakage. However, most homozygous deletions in cancer genomes are unexplained. Here we identified 2,428 somatic homozygous deletions in 746 cancer cell lines. These overlie 11% of protein-coding genes that, therefore, are not mandatory for survival of human cells. We derived structural signatures that distinguish between homozygous deletions over recessive cancer genes and fragile sites. Application to clusters of unexplained homozygous deletions suggests that many are in regions of inherent fragility, whereas a small subset overlies recessive cancer genes. The results illustrate how structural signatures can be used to distinguish between the influences of mutation and selection in cancer genomes. The extensive copy number, genotyping, sequence and expression data available for this large series of publicly available cancer cell lines renders them informative reagents for future studies of cancer biology and drug discovery.
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Affiliation(s)
- Graham R Bignell
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
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Zhao H, Du W, Wang D, Gu D, Xue F, Ge J, Sui T, Yang R. Single nucleotide polymorphism in the methyl-CpG binding domain 4 Gene and the risk for immune thrombocytopenic purpura in Chinese population. Platelets 2010; 21:132-6. [DOI: 10.3109/09537100903474365] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Whole blood genomic biomarkers of acute cardiac allograft rejection. J Heart Lung Transplant 2010; 28:927-35. [PMID: 19716046 DOI: 10.1016/j.healun.2009.04.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 03/17/2009] [Accepted: 04/10/2009] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Significant progress has been made in cardiac transplantation over the past 30 years; however, the means for detection of acute cardiac allograft rejection remains in need of improvement. At present, the endomyocardial biopsy, an invasive and inconvenient procedure for patients, is required for the surveillance and diagnosis of acute cardiac allograft rejection. In the Biomarkers in Transplantation initiative, we investigated gene expression profiles in peripheral blood of cardiac transplant subjects as potential biomarkers for diagnosis of allograft rejection. METHODS Whole blood samples were obtained from 28 cardiac transplant subjects who consented to the study. Serial samples were collected from pre-transplant through 3 years post-transplant according to the standard protocol. Temporally correspondent biopsies were also collected, reviewed in a blinded manner, and graded according to current ISHLT guidelines. Blood samples were analyzed using Affymetrix microarrays. Genomic profiles were compared in subjects with acute rejection (AR; ISHLT Grade > or =2R) and no rejection (NR; Grade 0R). Biomarker panel genes were identified using linear discriminant analysis. RESULTS We found 1,295 differentially expressed probe-sets between AR and NR samples and developed a 12-gene biomarker panel that classifies our internal validation samples with 83% sensitivity and 100% specificity. CONCLUSIONS Based on our current results, we believe whole blood genomic biomarkers hold great potential in the diagnosis of acute cardiac allograft rejection. A prospective, Canada-wide trial will be conducted shortly to further evaluate the classifier panel in diverse patients and a range of clinical programs.
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Collins SP, Dritschilo A. The mismatch repair and base excision repair pathways: an opportunity for individualized (personalized) sensitization of cancer therapy. Cancer Biol Ther 2009; 8:1164-6. [PMID: 19421005 DOI: 10.4161/cbt.8.12.8750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Sean P Collins
- Departments of Radiation Medicine and Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
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Abstract
The anti-metabolite 5-fluorouracil (5-FU) is employed clinically to manage solid tumors including colorectal and breast cancer. Intracellular metabolites of 5-FU can exert cytotoxic effects via inhibition of thymidylate synthetase, or through incorporation into RNA and DNA, events that ultimately activate apoptosis. In this review, we cover the current data implicating DNA repair processes in cellular responsiveness to 5-FU treatment. Evidence points to roles for base excision repair (BER) and mismatch repair (MMR). However, mechanistic details remain unexplained, and other pathways have not been exhaustively interrogated. Homologous recombination is of particular interest, because it resolves unrepaired DNA intermediates not properly dealt with by BER or MMR. Furthermore, crosstalk among DNA repair pathways and S-phase checkpoint signaling has not been examined. Ongoing efforts aim to design approaches and reagents that (i) approximate repair capacity and (ii) mediate strategic regulation of DNA repair in order to improve the efficacy of current anticancer treatments.
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Affiliation(s)
- M D Wyatt
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA.
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40
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Howard JH, Frolov A, Tzeng CWD, Stewart A, Midzak A, Majmundar A, Godwin A, Heslin M, Bellacosa A, Arnoletti JP. Epigenetic downregulation of the DNA repair gene MED1/MBD4 in colorectal and ovarian cancer. Cancer Biol Ther 2009; 8:94-100. [PMID: 19127118 DOI: 10.4161/cbt.8.1.7469] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
MED1 is a base excision repair enzyme that interacts with the mismatch repair protein MLH1 and maintains genomic integrity by binding methylated DNA and repairing spontaneous deamination events. MED1 mutations have been associated with microsatellite instability and accelerated colorectal cancer (CRC) tumorigenesis. We propose that promoter methylation may serve as an alternative epigenetic mechanism for MED1 gene suppression during sporadic CRC tumorigenesis. Methylation status of the MED1 promoter was investigated in a panel of ovarian and colorectal cancer cell lines. The MED1 promoter region was sequenced following bisulfite treatment and sequence analysis identified a CpG island within the MED1 promoter which is frequently and preferentially methylated (> or =50%) in ovarian and colorectal cancer cell lines with low/reduced MED1 expression. In vitro reversal of methylation restored MED1 expression. In colorectal cancer patients, when MED1 methylation was present, both tumor and matched mucosa were affected equally (mean frequency of methylation 24%) and there was no correlation between methylation and tumor stage. Patients without history of CRC showed significantly lower frequency of methylation (mean 14%, p < 0.05). Decreased MED1 transcript levels were observed in matched normal mucosa when compared to controls (median fold difference 8.0). Additional decreased expression was seen between mucosa and matched tumor (median fold decrease 4.4). Thus, MED1 promoter methylation and gene silencing occur in sporadic CRC patients and represent an early event in CRC tumorigenesis. Detection of MED1 methylation and gene suppression in normal colon mucosa may contribute to identifying patients at higher risk of developing CRC during screening procedures.
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Affiliation(s)
- J Harrison Howard
- Department of Surgery at the University of Alabama at Birmingham, USA
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41
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D'Errico M, de Rinaldis E, Blasi MF, Viti V, Falchetti M, Calcagnile A, Sera F, Saieva C, Ottini L, Palli D, Palombo F, Giuliani A, Dogliotti E. Genome-wide expression profile of sporadic gastric cancers with microsatellite instability. Eur J Cancer 2008; 45:461-9. [PMID: 19081245 DOI: 10.1016/j.ejca.2008.10.032] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 10/17/2008] [Indexed: 12/18/2022]
Abstract
Gastric cancers with mismatch repair (MMR) inactivation are characterised by microsatellite instability (MSI). In this study, the transcriptional profile of 38 gastric cancers with and without MSI was analysed. Unsupervised analysis showed that the immune and apoptotic gene networks efficiently discriminated these two cancer types. Hierarchical clustering analysis revealed numerous gene expression changes associated with the MSI phenotype. Amongst these, the p53-responsive genes maspin and 14-3-3 sigma were significantly more expressed in tumours with than without MSI. A tight immunosurveillance coupled with a functional p53 gene response is consistent with the better prognosis of MSI cancers. Frequent silencing of MLH1 and downregulation of MMR target genes, such as MRE11 and MBD4, characterised MSI tumours. The downregulation of SMUG1 was also a typical feature of these tumours. The DNA repair gene expression profile of gastric cancer with MSI is of relevance for therapy response.
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Affiliation(s)
- Mariarosaria D'Errico
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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42
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Baute J, Depicker A. Base excision repair and its role in maintaining genome stability. Crit Rev Biochem Mol Biol 2008; 43:239-76. [PMID: 18756381 DOI: 10.1080/10409230802309905] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
For all living organisms, genome stability is important, but is also under constant threat because various environmental and endogenous damaging agents can modify the structural properties of DNA bases. As a defense, organisms have developed different DNA repair pathways. Base excision repair (BER) is the predominant pathway for coping with a broad range of small lesions resulting from oxidation, alkylation, and deamination, which modify individual bases without large effect on the double helix structure. As, in mammalian cells, this damage is estimated to account daily for 10(4) events per cell, the need for BER pathways is unquestionable. The damage-specific removal is carried out by a considerable group of enzymes, designated as DNA glycosylases. Each DNA glycosylase has its unique specificity and many of them are ubiquitous in microorganisms, mammals, and plants. Here, we review the importance of the BER pathway and we focus on the different roles of DNA glycosylases in various organisms.
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Affiliation(s)
- Joke Baute
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, Gent, Belgium
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43
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Berger SH, Pittman DL, Wyatt MD. Uracil in DNA: consequences for carcinogenesis and chemotherapy. Biochem Pharmacol 2008; 76:697-706. [PMID: 18599024 DOI: 10.1016/j.bcp.2008.05.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 05/12/2008] [Accepted: 05/20/2008] [Indexed: 10/22/2022]
Abstract
The synthesis of thymidylate (TMP) occupies a convergence of two critical metabolic pathways: folate metabolism and pyrimidine biosynthesis. Thymidylate is formed from deoxyuridylate (dUMP) using N(5),N(10)-methylene tetrahydrofolate. The metabolic relationship between dUMP, TMP, and folate has been the subject of cancer research from prevention to chemotherapy. Thymidylate stress is induced by nutritional deficiency of folic acid, defects in folate metabolism, and by antifolate and fluoropyrimidine chemotherapeutics. Both classes of chemotherapeutics remain mainstay treatments against solid tumors. Because of the close relationship between dUMP and TMP, thymidylate stress is associated with increased incorporation of uracil into DNA. Genomic uracil is removed by uracil DNA glycosylases of base excision repair (BER). Unfortunately, BER is apparently problematic during thymidylate stress. Because BER requires a DNA resynthesis step, elevated dUTP causes reintroduction of genomic uracil. BER strand break intermediates are clastogenic if not repaired. Thus, BER during thymidylate stress appears to cause genome instability, yet might also contribute to the mechanism of action for antifolates and fluoropyrimidines. However, the precise roles of BER and its components during thymidylate stress remain unclear. In particular, links between BER and downstream events remain poorly defined, including damage signaling pathways and homologous recombination (HR). Evidence is growing that HR responds to persistent BER strand break intermediates and DNA damage signaling pathways mediate cross talk between BER and HR. Examination of crosstalk among BER, HR, and damage signaling may shed light on decades of investigation and provide insight for development of novel chemopreventive and chemotherapeutic approaches.
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Affiliation(s)
- Sondra H Berger
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA.
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44
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Tagging single nucleotide polymorphisms in MBD4 are associated with risk of lung cancer in a Chinese population. Lung Cancer 2008; 62:281-6. [PMID: 18495292 DOI: 10.1016/j.lungcan.2008.03.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 03/20/2008] [Accepted: 03/29/2008] [Indexed: 11/23/2022]
Abstract
MBD4 (methyl-CpG binding domain protein 4) was identified as a methyl-CpG binding protein and plays an important role in DNA methylation and carcinogenesis. We hypothesized that genetic variants in MBD4 were associated with lung cancer risk. We selected and genotyped three tagging SNPs (rs2311394, rs140693, and rs2005618) of MBD4 using the illumina SNP genotyping BeadLab platform in a case-control study of 500 incident lung cancer patients and 517 cancer-free controls in a Chinese population. We observed a significantly decreased risk of lung cancer associated with the rs140693 GA genotype (adjusted OR=0.70, 95% CI=0.52-0.93), and the combined rs140693 GA/AA variant genotypes (adjusted OR=0.76, 95% CI=0.58-1.00), compared with the wild-type homozygote rs140693 GG. The reduced lung cancer risk in non-smokers carrying rs140693 GA/AA genotypes was more predominant (adjusted OR=0.56, 95% CI=0.35-0.87). However, there was no statistic evidence of gene-smoking interaction. These findings suggest that genetic variants of MBD4 rs140693 may modulate risk of lung cancer. Further larger case-control and functional studies are needed to validate these findings.
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45
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Abdel-Rahman WM, Knuutila S, Peltomäki P, Harrison DJ, Bader SA. Truncation of MBD4 predisposes to reciprocal chromosomal translocations and alters the response to therapeutic agents in colon cancer cells. DNA Repair (Amst) 2007; 7:321-8. [PMID: 18162445 DOI: 10.1016/j.dnarep.2007.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 10/18/2007] [Accepted: 11/06/2007] [Indexed: 01/27/2023]
Abstract
We previously identified a novel genomic instability phenotype of multiple reciprocal chromosomal translocations in a MLH1-defective, microsatellite unstable (MSI) colon cancer cell line (HCA7) and, further, showed that it was unlikely to be directly caused by the mismatch repair (MMR) defect in this cell line. To gain insight into the molecular basis to this novel translocation phenotype, we examined coding and splice-site nucleotide repeat tracts in DNA repair genes for mutations by direct sequencing together with RT-PCR expression analysis of the associated transcript. The material was a selected panel of 8 MSI cell lines including HCA7. A strong candidate identified through this approach was MBD4 as it showed a homozygous truncating mutation associated with substantial loss of the transcript in HCA7 not seen in the other lines. In previous published studies, heterozygous MBD4 mutations were observed in up to 89% of sporadic MSI microdissected colon tumor foci. Using MFISH, we show that over-expression of the truncated MBD4 (+MBD4(tru)) in DLD1, a MSH6 defective, MSI human colon carcinoma cell line predisposed these cells to acquire structural chromosomal rearrangements including multiple reciprocal translocations after irradiation, reminiscent of those seen in HCA7. We also show that over-expression of MBD4(tru) in DLD1 alters the colony survival after exposure to cisplatin or etoposide. These data suggest a wide role for MBD4 in DNA damage response and maintaining chromosomal stability.
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46
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Abstract
The strongest and undisputed fact about p53 is the high frequency of p53 alterations in human cancer and that mutant p53 proteins constitute a complex family of several hundred proteins with heterogeneous properties. Beyond these observations, the p53 pathway and its regulation in a normal cell is like a desert trail, always moving with the wind of novel findings. The field is full of black boxes that are often ignored for sake of simplicity or because they do not fit with the current dominant view. Mutant p53 protein accumulation in tumours is the best example of a preconceived idea, as there is no experimental evidence to explain this observation. In this review, we will discuss several questions concerning the activity or selection of p53 mutations. The central domain of the p53 protein targeted by 80% of p53 mutations is associated with the DNA-binding activity of the p53 protein, but it is also the binding site for several proteins that play a key role in p53 regulation such as ASPP proteins or BclxL. The role of impaired DNA binding and/or protein interactions in tumour development has not been fully elucidated. Similarly, novel animal models carrying either missense p53 mutations or inducible p53 have provided abundant observations, some of which could challenge our view on p53 function as a tumour suppressor gene. Finally, the possible clinical applications of p53 will be discussed.
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Affiliation(s)
- T Soussi
- Department of Life Sciences, Université Pierre et Marie Curie-Paris, Paris, France.
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47
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Sansom OJ, Maddison K, Clarke AR. Mechanisms of disease: methyl-binding domain proteins as potential therapeutic targets in cancer. ACTA ACUST UNITED AC 2007; 4:305-15. [PMID: 17464338 DOI: 10.1038/ncponc0812] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 11/02/2006] [Indexed: 12/22/2022]
Abstract
The methyl-CpG-binding domain (MBD) proteins 'read' and interpret the methylation moieties on DNA, and thus are critical mediators of many epigenetic processes. Currently, the MBD family comprises five members; MBD1, MBD2, MBD3, MBD4 and MeCP2. Although not a 'classical' MBD protein, Kaiso also mediates transcriptional repression by using zinc finger domains to bind its targets. Since DNA hypermethylation is a well-recognized mechanism underlying gene silencing events in both tumorigenesis and drug resistance, it is likely that the MBD proteins may be important modulators of tumorigenesis. We review the recent work addressing this possibility, and discuss several of the MBD proteins as potentially excellent novel therapeutic targets.
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Affiliation(s)
- Owen J Sansom
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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48
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Hwang CK, Song KY, Kim CS, Choi HS, Guo XH, Law PY, Wei LN, Loh HH. Evidence of endogenous mu opioid receptor regulation by epigenetic control of the promoters. Mol Cell Biol 2007; 27:4720-36. [PMID: 17452465 PMCID: PMC1951474 DOI: 10.1128/mcb.00073-07] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The pharmacological effect of morphine as a painkiller is mediated mainly via the mu opioid receptor (MOR) and is dependent on the number of MORs in the cell surface membrane. While several studies have reported that the MOR gene is regulated by various cis- and trans-acting factors, many questions remain unanswered regarding in vivo regulation. The present study shows that epigenetic silencing and activation of the MOR gene are achieved through coordinated regulation at both the histone and DNA levels. In P19 mouse embryonal carcinoma cells, expression of the MOR was greatly increased after neuronal differentiation. MOR expression could also be induced by a demethylating agent (5'-aza-2'-deoxycytidine) or histone deacetylase inhibitors in the P19 cells, suggesting involvement of DNA methylation and histone deacetylation for MOR gene silencing. Analysis of CpG DNA methylation revealed that the proximal promoter region was unmethylated in differentiated cells compared to its hypermethylation in undifferentiated cells. In contrast, the methylation of other regions was not changed in either cell type. Similar methylation patterns were observed in the mouse brain. In vitro methylation of the MOR promoters suppressed promoter activity in the reporter assay. Upon differentiation, the in vivo interaction of MeCP2 was reduced in the MOR promoter region, coincident with histone modifications that are relevant to active transcription. When MeCP2 was disrupted using MeCP2 small interfering RNA, the endogenous MOR gene was increased. These data suggest that DNA methylation is closely linked to the MeCP2-mediated chromatin structure of the MOR gene. Here, we propose that an epigenetic mechanism consisting of DNA methylation and chromatin modification underlies the cell stage-specific mechanism of MOR gene expression.
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Affiliation(s)
- Cheol Kyu Hwang
- Department of Pharmacology, University of Minnesota, 6-120 Jackson Hall, 321 Church St. S.E., Minneapolis, MN 55455, USA.
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49
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Bader SA, Walker M, Harrison DJ. A human cancer-associated truncation of MBD4 causes dominant negative impairment of DNA repair in colon cancer cells. Br J Cancer 2007; 96:660-6. [PMID: 17285135 PMCID: PMC2360052 DOI: 10.1038/sj.bjc.6603592] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 12/04/2006] [Accepted: 12/18/2006] [Indexed: 12/30/2022] Open
Abstract
MBD4 binds to methylated DNA and acts as a thymine DNA glycosylase in base excision repair. Deficiency of MBD4 in mice enhances mutation at CpG sites and alters apoptosis in response to DNA damage, but does not increase tumorigenesis in mismatch repair-deficient mice. However, in humans, frameshift mutation of MBD4, rather than deletion, is what occurs in up to 43% of microsatellite unstable colon cancers. There is no murine equivalent of this mutation. We now show that recombinant truncated MBD4 (MBD4(tru)) inhibits glycosylase activities of normal MBD4 or Uracil DNA glycosylase in cell-free assays as a dominant negative effect. Furthermore, overexpression of MBD4(tru) in Big Blue (lacI)-transfected, MSI human colorectal carcinoma cells doubled mutation frequency, indicating that the modest dominant negative effect on DNA repair can occur in living cells in short-term experiments. Intriguingly, the whole mutation spectrum was increased, not only at CpG sites, suggesting that truncated MBD4 has a more widespread effect on genomic stability. This demonstration of a dominant negative effect may be of significance in tumour progression and acquisition of drug resistance.
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Affiliation(s)
- S A Bader
- Department of Pathology, Edinburgh Cancer Research Centre, University of Edinburgh, Crewe Road, Edinburgh EH4 2XR, UK.
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50
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Turner DP, Cortellino S, Schupp JE, Caretti E, Loh T, Kinsella TJ, Bellacosa A. The DNA N-glycosylase MED1 exhibits preference for halogenated pyrimidines and is involved in the cytotoxicity of 5-iododeoxyuridine. Cancer Res 2006; 66:7686-93. [PMID: 16885370 DOI: 10.1158/0008-5472.can-05-4488] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The base excision repair protein MED1 (also known as MBD4), an interactor with the mismatch repair protein MLH1, has a central role in the maintenance of genomic stability with dual functions in DNA damage response and repair. MED1 acts as a thymine and uracil DNA N-glycosylase on T:G and U:G mismatches that occur at cytosine-phosphate-guanine (CpG) methylation sites due to spontaneous deamination of 5-methylcytosine and cytosine, respectively. To elucidate the mechanisms that underlie sequence discrimination by MED1, we did single-turnover kinetics with the isolated, recombinant glycosylase domain of MED1. Quantification of MED1 substrate hierarchy confirmed MED1 preference for mismatches within a CpG context and showed preference for hemimethylated base mismatches. Furthermore, the k(st) values obtained with the uracil analogues 5-fluorouracil and 5-iodouracil were over 20- to 30-fold higher than those obtained with uracil, indicating substantially higher affinity for halogenated bases. A 5-iodouracil precursor is the halogenated nucleotide 5-iododeoxyuridine (5IdU), a cytotoxic and radiosensitizing agent. Cultures of mouse embryo fibroblasts (MEF) with different Med1 genotype derived from mice with targeted inactivation of the gene were evaluated for sensitivity to 5IdU. The results revealed that Med1-null MEFs are more sensitive to 5IdU than wild-type MEFs in both 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation assays. Furthermore, high-performance liquid chromatography analyses revealed that Med1-null cells exhibit increased levels of 5IdU in their DNA due to increased incorporation or reduced removal. These findings establish MED1 as a bona fide repair activity for the removal of halogenated bases and indicate that MED1 may play a significant role in 5IdU cytotoxicity.
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Affiliation(s)
- David P Turner
- Human Genetics Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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