title: A novel functional polymorphism in the Cdc6 promoter is associated with the risk for hepatocellular carcinoma.
abstract: Cdc6 is essential for DNA replication and its deregulation is involved in carcinogenesis. To date, the biological significance of the polymorphism in Cdc6 promoter is still unknown. In this study, we aimed to evaluate the influence of the Cdc6 -515A>G polymorphism (rs4134994) on the individual's susceptibility to cancer and on the function of Cdc6. The Cdc6 -515A>G polymorphism was genotyped in 387 hepatocellular carcinoma (HCC) and 389 age- and sex-matched healthy subjects. The association between the genotypes and the risk for HCC was then estimated by unconditional logistic regression analysis with adjustment for age, sex and HBV status. Compared with the AA homozygotes, the homozygous GG genotype (adjusted OR=0.36, 95% confidence interval (CI)=0.18-0.72, P=0.004) or the combined AG/GG genotypes (adjusted OR=0.56, 95% CI=0.36-0.86, P=0.008) were statistically significantly associated with the reduced risk for HCC. Moreover, the analysis using luciferase reporter system showed that the G-allelic Cdc6 promoter displayed a decreased transcriptional activity compared with the A-allelic one. These results indicate that the individuals with G allele may have reduced Cdc6 expression and are therefore in reduced risk for HCC. Further investigation using electrophoretic mobility shift assay (EMSA) revealed that the G allele had a stronger binding strength to nuclear protein(s) which might function as negative regulator(s) for Cdc6 transcription. Our findings suggest that the -515A>G polymorphism may affect the Cdc6 promoter binding affinity with nuclear protein(s) and in turn the Cdc6 expression, which consequently modulates the individual's susceptibility to HCC.
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Xing-Dong
authors.initials: XD
authors.lastname: Xiong
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Fang
authors.forename: Fu-En
authors.initials: FE
authors.lastname: Qiu
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Jiasen
authors.initials: J
authors.lastname: Cheng
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Yuan
authors.forename: Sheng-Ping
authors.initials: SP
authors.lastname: Li
authors.forename: Shi-Mei
authors.initials: SM
authors.lastname: Zhuang
mesh_terms: D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D018797:Cell Cycle Proteins / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012307:Risk Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: C103706:CDC6 protein, human; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D008156:Luciferases