CDH1基因启动子甲基化在上皮性卵巢癌转移方面的研究

Correlation of the methylation status of CDH1 gene promoter and the metastasis of human epithelial ovarian carcinomas

目的探讨CDH1基因启动子甲基化对上皮性卵巢癌转移的影响。方法采用免疫组织化学方法检测38例正常卵巢上皮和80例上皮性卵巢癌组织中E-钙黏附素(E-cadherin)表达;应用甲基化特异的PCR(MSP)检测上述组织中CDH1基因启动子区甲基化;应用5-氮-2′-脱氧胞苷(5-aza-CdR)使SKOV3细胞去甲基化,观察SKOV3细胞体外侵袭性的改变,并通过RT-PCR检测CDH1基因的改变。结果E-cadherin在正常卵巢组织中表达明显高于上皮性卵巢癌(P<0.05)。34例CDH1基因启动子区甲基化全部出现在卵巢癌组织中,有淋巴结转移组织中甲基化明显高于无淋巴结转移者(P<0.05),而CDH1基因启动子区有甲基化的卵巢癌组织中E-cadherin表达明显降低(P<0.05)。经5-Aza-CdR处理后的SKOV3细胞体外侵袭性降低(P<0.01),CDH1基因的表达明显上调(P<0.01)。结论E-cadherin表达降低与上皮性卵巢癌转移关系密切,CDH1基因启动子区甲基化可能是导致E-cadherin蛋白表达减低的重要原因之一,因此启动子区甲基化与上皮性卵巢癌转移有关。

Objective To investigate the effects of methylation of CDH1 gene promoter on the metastasis of human epithelial ovarian carcinomas. Methods The expression of E-cadherin in 80 primary epithelial ovarian carcinomas and 38 normal ovarian tissues was detected by immunohistochemistry, and then the methylation status was measured by the methylation specific PCR （MSP）. The expression of CDH1 gene mRNA in SKOV3 cell and the invasion efficiency of SKOV3 cell were studied when the cell was demethylated by 5-Aza-2＇-deoxyeytidine （5-aza-CdR）. Results Compared with the normal control, the expression of E-cadherin was significantly lower in the tumor tissues （P 〈 0.05）. Thirty-four specimens of methylation of CDH1 gene promoter were all from the epithelial ovarian carcinomas. The degree of methylation of CDH1 promoter in tissues with local lymph node metastasis was significantly higher than that in tissues without local lymph node metastasis （P 〈 0.05）. And the expression of E-cadherin reduced significantly in those who have a methylated CDH1 promoter （P 〈 0.01）. The SKOV3 cell treated by 5-aza-CdR demonstrated a high expression of CDH1 gene and low invasion efficiency （P 〈 0.01）. Conclusion Low expression of E-cadherin is closely related with the metastasis of epithelial ovarian carcinoma. As a probable cause of down regulation of E-cadhefin, methylation of CDH1 gene promoter may also play an important role in the metastasis of epithelial ovarian carcinomas.