人胃癌细胞株CDX2基因表达与其启动子区甲基化的关系

Relationship between CDX2 gene expression and its DNA methylation in human gastric cancer cell lines

目的:探讨人胃癌细胞株CDX2基因表达与其启动子区甲基化的关系。方法:不同浓度5-aza-CdR处理MKN45细胞株,甲基化特异性PCR(MSP)检测用药前后CDX2启动子甲基化状态;实时荧光定量RT-PCR和WesternBlot分别检测CDX2和DNMT1 mRNA和蛋白表达。结果:MKN45细胞株CDX2基因启动子区域高甲基化,CDX2 mRNA表达极低,蛋白不表达;经3种浓度5-aza-CdR处理MKN45细胞72 h后,细胞中CDX2 mRNA和蛋白表达均出现上调,而DNMT1表达出现下调。结论:CDX2基因表达下调与其启动子CpG岛高甲基化有关,DNMT1可能参与该过程的调节。

Objective： To explore the relationship between CDX2 gene expression and its DNA methylation in human gastric cancer cell lines.Methods： The status of 5＇CpG island methylation of CDX2 gene was analyzed by methylation specific PCR（MSP）.Real-time PCR and Western Blot assay were used to examine the expression of CDX2 and DNMT1 mRNA and protein.Results： MSP shows promoter hypermethylation of CDX2 gene existed,and the CDX2 mRNA and protein were not expressed in MKN45 cells.After 5-Aza-CdR treatment for 72 h,hypermehtylated CDX2 gene was demethylated and CDX2 gene was expressed with different doses of 5-aza-CdR in MKN45 cells.However,expression of DNMT1 was inverse correlation with that of CDX2 in gastric cancer cell lines.Conclusion： The over-expression of DNMT1 and 5＇CpG island methylation of CDX2 gene is probably responsible for CDX2 silencing in gastric cancer cell lines.