目的： 探讨DNA甲基化抑制剂5-氮杂胞苷（5-Aza-2’-deoxycytidine，5-Aza-CdR）在增强人非小细胞肺癌（non-small cell lung cancer，NSCLC）细胞对吉非替尼敏感性中的作用及其机制。 方法： 选取EGFR突变型NSCLC细胞株H1650及EGFR野生型NSCLC细胞株H1299，5-Aza-CdR处理后，CCK-8法检测H1650及H1299细胞对吉非替尼敏感性的变化，real-time PCR检测细胞中miR-200c及表皮生长因子受体（epidermal growth factor receptor，EGFR）mRNA的表达水平。 结果： EGFR突变型及野生型NSCLC细胞株 H1650、H1299对吉非替尼有一定程度的耐药性，5-Aza-CdR处理后H1650及H1299细胞对吉非替尼的敏感性显著增强，表现为吉非替尼对细胞的IC50明显降低\[（1.04±0.35） vs（159.37±17.48) μmol/L，（6.28±1.02） vs （22376±23.63）μmol/L；均P<0.01\]。Real-time PCR检测结果显示，5-Aza-CdR处理后EGFR突变型或野生型H1650、H1299细胞中miR-200c \[（0.009±0.003） vs （0.002±0.001），（0.004±0.001）vs 0；均P<0.01\]和EGFR mRNA\[（0.286±0037）vs （0.015±0.012），（0.057±0.014） vs （0.01±0.01）；均P<0.01\]的表达水平均显著增高。 结论： DNA甲基化抑制剂5-Aza-CdR可上调NSCLC细胞中miR-200c及EGFR mRNA的表达，增强其对吉非替尼的敏感性。

Objective:To explore the effect of DNA methylation inhibitor 5-Aza-2’-deoxycytidine (5-Aza-CdR) on enhancing the sensitivity of human non-small cell lung cancer (NSCLC) cells to gefitinib and its mechanisms. Methods: EGFR mutant NSCLC cell line H1650 and EGFR wild type NSCLC cell line H1299 were used in this study. The changes in sensitivity of H1650 and H1299 cells to gefitinib after 5-Aza-CdR treatment were detected by CCK-8 assay. The expression levels of miR-200c and epidermal growth factor receptor (EGFR) mRNA were evaluated by real-time PCR. Results: EGFR mutant and wild type NSCLC cell lines H1650 and H1299 showed a certain degree of drug resistance to gefitinib. The sensitivity of H1650 and H1299 cells to gefitinib ncreased after 5-Aza-CdR treatment, with IC50 value of gefitinib to cells decreasing significantly (\[1.04±0.35\] vs \[159.37±17.48\] μmol/L, \[6.28±1.02\] vs \[223.76±23.63\] μmol/L, P<0.01). Real-time PCR assay results showed that the expression level of miR-200c was increased in EGFR mutant H1650 cells or wild type H1299 cells after 5-Aza-CdR treatment (\[0.009±0.003\] vs \[0.002±0.001\], \[0.004±0.001\] vs 0, P<0.01), respectively. Besides, the expression level of EGFR mRNA was significantly increased compared with 5-Aza-CdR untreated group (\[0.286±0.037\] vs \[0.015±0.012\], \[0.057±0014\] vs \[001±0.01\], P<0.01). Conclusion: The expressions of miR-200c and EGFR mRNA in human NSCLC H1650 and H1299 cells are up-regulated by DNA methylation inhibitor 5-Aza-CdR, which increases the sensitivity of H1650 and H1299 cells to gefitinib.

江苏省科技厅科研基金资助（No. BK2009446）；吴阶平医学基金资助（No. 320.6700.09050）