title: Aberrant gene promoter methylation of p16, FHIT, CRBP1, WWOX, and DLC-1 in Epstein-Barr virus-associated gastric carcinomas.
abstract: Alterations in global DNA methylation and specific regulatory gene methylation are frequently found in cancer, but the significance of these epigenetic changes in EBV-associated gastric carcinoma (EBVaGC) remains unclear. We evaluated global DNA methylation status in 49 EBVaGC and 45 EBV-negative gastric carcinoma (EBVnGC) tissue samples and cell lines by 5-methylcytosine immunohistochemical staining and methylation quantification. We determined promoter methylation status and protein expression for the p16, FHIT, CRBP1, WWOX, and DLC-1 genes in tissues and studied the correlation between CpG island methylator phenotype (CIMP) class and clinicopathological characteristics. Changes in gene methylation and mRNA expression in EBVaGC cell line SNU-719 and in EBVnGC cell lines SGC-7901, BGC-823, and AGS were assessed after treatment with 5-aza-2'-deoxycytidine (5-aza-dC), trichostatin A (TSA), or a combination of both, by methylation-specific PCR and quantitative real-time RT-PCR. Global genomic DNA hypomethylation was more pronounced in EBVnGC than in EBVaGC. Promoter methylation of all five genes was more frequent in EBVaGC than in EBVnGC (p < 0.05). p16 and FHIT methylation was reversely correlated with protein expression in EBVaGC. Most (41/49) EBVaGC exhibited CIMP-high (CIMP-H), and the prognosis of CIMP-H patients was significantly worse than that of CIMP-low (p = 0.027) and CIMP-none (p = 0.003) patients. Treatment with 5-aza-dC and/or TSA induced upregulation of RNA expression of all five genes in SNU-719; meanwhile, individual gene expression increased in EBVnGC cell lines. In summary, EBV-induced hypermethylation of p16, FHIT, CRBP1, WWOX, and DLC-1 may contribute to EBVaGC development. Demethylation therapy may represent a novel therapeutic strategy for EBVaGC.
authors.affiliation: Department of Pathology, The Third Affiliated Hospital, Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou, 510630, Guangdong Province, China.
authors.forename: Dan
authors.initials: D
authors.lastname: He
authors.forename: Yi-wang
authors.initials: YW
authors.lastname: Zhang
authors.forename: Na-na
authors.initials: NN
authors.lastname: Zhang
authors.forename: Lu
authors.initials: L
authors.lastname: Zhou
authors.forename: Jian-ning
authors.initials: JN
authors.lastname: Chen
authors.forename: Ye
authors.initials: Y
authors.lastname: Jiang
authors.forename: Chun-kui
authors.initials: CK
authors.lastname: Shao
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000235:genetics; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics*; D049109:Cell Proliferation; D018899:CpG Islands / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics; D020031:Epstein-Barr Virus Infections / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000821:virology; D005260:Female; D005500:Follow-Up Studies; D020690:GTPase-Activating Proteins / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D004854:Herpesvirus 4, Human / Q000472:pathogenicity; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics; D009367:Neoplasm Staging; D010088:Oxidoreductases / Q000235:genetics; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018168:Receptors, Retinoic Acid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology* / Q000821:virology; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000235:genetics; D000074584:WW Domain-Containing Oxidoreductase; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; D020690:GTPase-Activating Proteins; D009363:Neoplasm Proteins; D010088:Oxidoreductases; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D025521:Tumor Suppressor Proteins; D000074584:WW Domain-Containing Oxidoreductase; D000099170:Bis(5'-adenosyl)triphosphatase; C000614131:CDKN2A protein, human; C112352:DLC1 protein, human; C082927:retinoic acid binding protein I, cellular; C486071:WWOX protein, human