乙肝病毒X蛋白通过DNA甲基化沉默肝癌中miR-338表达

HBx Suppresses miR-338 Expression in Hepatoma via DNA Hypermethylation

目的将HBx相关的DNA甲基化和非编码RNA异常变化联系起来,研究二者是否存在相互作用.方法利用高通量芯片及qRT-PCR证实HBx在肝癌细胞和组织内下调miR-338表达.通过系列蛋白/mRNA/表达分析,启动子甲基化检测来研究HBx下调miR-338的机制.结果芯片及qRT-PCR显示HBx在肝癌细胞和组织内下调miR-338的表达.HBx在HepG2肝癌细胞内显著上调DNMT 1和DNMT 3A的表达.HBV阳性肝癌组织中miR-338启动子甲基化程度显著高于癌旁正常组织,去甲基化处理能挽救肝癌细胞中miR-338表达.结论HBx在体内外显著抑制肝癌中miR-338表达并上调肝癌细胞中DNMT 1和DNMT 3A表达.miR-338启动子过甲基化是其沉默的内在机制.

Objective To explore the intereaction between hypermethylation and non-coding RNAs related to Hepatitis B virus X protein（HBx）.hypermethylation.Methods miRNA microarray and quantitative reverse-transcription polymerase chain reactions（qRT-PCRs） were performed to confirm that HBx suppressed miR-338 expression in HCC cells.Protein,mRNA,miRNA expression analyses and promotor methylation detections were performed to delineate the mechanisms of HBx/HBV associated miR-338 repression in HCC.Results HBx suppressed miR-338 expression in HCC tissues and cells,while upregulating expression of DNMT1 and DNMT3A.The promotor methlation status of miR-338 was significantly higher in HBV＋HCC tumors than adjacent tissues,while demethylation treatment could rescue the miR-338 expression in HBx＋HCC cells.Conclus ions HBx can downregulate the expression of miR-338,while upregulate DNMT 3 A and DNMT 1 expression.The HBx associated promotor hypermethylation of miR-338 is responsible for its silence.