miR-200c启动子区甲基化与肺癌细胞对EGFR-TKI耐药相关

目的:初步探讨miR-200c启动子区甲基化与非小细胞肺癌细胞株对表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor-tyrosine kinase inhibitor,EGFR-TKI)敏感性变化的关系。方法:选用表皮生长因子受体(epidermal growth factor receptor,EGFR)19外显子区缺失突变(E746-A750)的细胞株(H1650、HCC827)及EGFR野生型细胞株(H358、H1299),应用MSP法检测各细胞株miR-200c启动子区的甲基化状态,CCK-8法检测各细胞株对EGFR-TKI吉非替尼的药物敏感性,荧光定量PCR法检测各细胞株miR-200c的相对表达量;去甲基化药物5-aza-CdR处理各细胞株后,观察其对吉非替尼敏感性及miR-200c表达量的变化。结果:吉非替尼敏感细胞株HCC827及H358高表达miR-200c,其启动子区为非甲基化状态;吉非替尼耐药细胞株H1650及H1299的miR-200c表达较低,其启动子区为甲基化状态;经5-aza-CdR处理后,吉非替尼耐药细胞株H1650及H1299的miR-200c及对吉非替尼的敏感性较前显著升高,差异具有统计学意义(P<0.05);而吉非替尼敏感株HCC827及H358的miR-200c及对吉非替尼的敏感性未见有明显改变(P>0.05)。结论:miR-200c启动子区的甲基化抑制了miR-200c的表达,从而使H1650及H1299细胞对吉非替尼耐药。

Hyperm ethylation of miR-200c promoter correlated with EGFR-TKI resistance in lung cancer cells

Objective:To examine the relationship between miR-200c promoter methylation and the response of non small cell lung cancer(NSCLC)cells to(TKI). Methods:NSCLC cell lines H1650,HCC827 with EGFR 19 deletion and cell lines H358 and H1299 with wild type EGFR were used in this study. The methylation of miR-200c promoter region was examined by methylation-specific PCR (MSP). The response of different cell lines to gefitinib was examined by cell counting kit-8 (CCK-8)assay. The expression of miR-200c was examined by RT-PCR. When treated with 5-aza-CdR,the response to gefitinib and miR-200c expression of four cell lines H1650,HCC827,H358 and H1299 were observed. Results:HCC827 and H358,which were sensitive to gefitinib,highly expressed miR-200c with promoter unmethylated. H1650 and H1299,which were insensitive to gefitinib,expressed low levels of miR-200c with promoter methylated. When treated with 5-aza-CdR,H1650 and H1299 expressed higher miR-200c and were more sensitive to gefitinib than before (P < 0.05),while HCC827 and H358 had no alteration in miR-200c expression and the sensibility to gefitinib(P > 0.05). Conclusion: As methylation of gene promoter suppressed the expression of miR-200c, the lung cancer cell lines H1650 and H1299 can be insensitive to gefitinib.