胃癌细胞中BNIP3基因CpG岛甲基化及其调控作用

摘要

Objective To detect the methylation status of the promoter of BNIP3 gene in gastric cancer cell lines MKN1,and to explore the mecha⁃nism of DNA methylation regulating the expression of BNIP3 in gastric cancer cells. Methods The methylation status of BNIP3 promoter was de⁃tected by bisulfate sequencing PCR. Reverse transcription PCR was used to evaluate BNIP3 mRNA expression. MKN1 cells were treated with 5⁃Aza⁃2′⁃deoxycytidine(5⁃Aza⁃CdR),and after the treatment,the methylation status and BNIP3 mRNA expression were observed. Chromatin immuno⁃precipitation(ChIP)was used to determine the combination of BNIP3 with DNA methyltransferase 1(DNMT1). Results The promoter DNA of BNIP3 in MKN1 cells was in state of hypermethylation. Compared to the control group,methylation status and mRNA expression of BNIP3 in the drug treatment group(the 5⁃Aza⁃CdR concentration was 10μmol/L)were reversed,which showed statistical differences(P<0.05). 5⁃Aza⁃CdR inhibited the combination of BNIP3 with DNMT1. Conclusion CpG island methylation regulates BNIP3 gene expression in MKN1 cells. DNA methylation is related with the binding between the promoter of BNIP3 and DNMT1.%目的：观察胃癌细胞株MKN1中BNIP3基因启动子区的甲基化状态，探讨DNA甲基化调控BNIP3表达的机制。方法应用亚硫酸氢盐修饰后克隆测序法检测MKN1细胞中BNIP3基因启动子区的甲基化状态，应用甲基化抑制剂5⁃氮杂⁃2′⁃脱氧胞苷（5⁃Aza⁃CdR）处理MKN1细胞，观察给药前后BNIP3 mRNA表达及启动子区CpG岛甲基化状态的改变。应用染色质免疫沉淀技术检测BNIP3基因与DNA甲基化转移酶1（DNMT1）的结合。结果 MKN1细胞中BNIP3基因启动子区呈高甲基化状态。应用5⁃Aza⁃CdR处理细胞后，药物处理组（5⁃Aza⁃CdR浓度为10μmol/L）和对照组甲基化率和BNIP3 mRNA表达的差异均有统计学意义（P<0.05）。5⁃Aza⁃CdR抑制MKN1细胞中DNMT1与BNIP3基因的结合。结论 MKN1细胞中BNIP3基因表达受启动子区CpG岛甲基化调控，DNA甲基化的发生与DNMT1和BNIP3基因结合有关。