涎腺腺样囊性癌细胞系中DNA甲基化研究

DNA methylation in salivary adenoid cystic carcinoma cell lines

目的探讨涎腺腺样囊性癌(adenoid cystic carcinoma,ACC)细胞系中抑癌基因甲基化状况及其与 mRNA、蛋白表达之间的关系。方法甲基化特异性 PCR 法检测 ACC 细胞系 ACC-2、ACC-3、ACC-M 中 E-钙黏着蛋白(E-cadherin,E-cad)、p16、RASSF1A、DAPK、MGMT 基因启动子区的甲基化状况。应用 RT-PCR 方法和免疫组织化学方法检测 E-cad、p16在 mRNA 和蛋白水平的表达。结果 3个 ACC 细胞系中均检测到 E-cad、p16基因的甲基化,而没有 RASSF1A、DAPK、MGMT 基因的甲基化;mRNA 和蛋白水平均未检测到 E-cad 的表达,均检测到 p16的表达。结论 ACC 细胞系中,E-cad、p16基因启动子区的甲基化是常见事件,甲基化可能是 E-cad 基因失活的主要机制之一。

Objective To investigate the promoter methylation status of tumor supressor gene and the relationship between promoter methylation and mRNA, protein expression of tumor suppressor gene in salivary adenoid cystic carcinoma （ACC） cell lines. Methods Promoter methylation status of E-cad, p16, RASSF1A, DAPK, and MGMT was determined by methylation-specific polymerase chain reaction （MSP） in ACC cell lines,ACC-2 ,ACC-3 ,and ACC-M. E-cad, p16 protein and mRNA expression was also examined by IHC and RT-PCR in 3 ACC cell lines. Results All the three salivary ACC cell lines exhibited E-cad, p16 promoter methylation, but no methylation of RASSF1A, DAPK, and MGMT was found. There was p16 protein and mRNA expression but no E-cad expression in 3 ACC cell lines. Conclusions The results suggest that in ACC cell lines, promoter methylation of E-cad, p16 is a common event, and promoter methylation may be one of the major mechanism for inactivation of E-cad.