涎腺腺样囊性癌细胞系中DNA甲基化研究

目的探讨涎腺腺样囊性癌（adenoidcysticcarcinoma，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、RASSFlA、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RASSFlA、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。

DNA methylation in salivary adenoid cystic carcinoma cell lines

OBJECTIVE: To investigate the promoter methylation status of tumor suppressor 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.