目的 探讨氟维司群逆转吉非替尼耐药非小细胞肺癌细胞株耐药性的可能性及其机制.方法 分别用不同浓度的氟维司群和吉非替尼,单药以及联合对非小细胞肺癌细胞株H1975[含表皮生长因子受体(EGFR)L858R&T790m突变]、H1650(含EGFR Del E746-A750&PTEN De突变)、PC-9(含EGFR Del E746-A750突变)细胞进行干预后,采用MTT法检测细胞增殖变化,Western blot法检测EGFR、雌激素受体(ER)、磷酸化表皮生长因子受体(p-EGFR)的蛋白表达.结果①H1975、H1650、PC-9肺癌细胞中均有EGFR及ER表达;②吉非替尼及氟维司群联合用药较单药可明显抑制H1975、H1650、PC-9肺癌细胞的增殖(P<0.001);③H1975耐药细胞株内T790m突变型EGFR的磷酸化水平可以快速地被雌激素升高或被氟维司群抑制;④ 在酪氨酸激酶抑制剂(EGFR-TKI)获得性耐药的肺癌细胞株中雌激素、表皮生长因子(EGF)分别下调EGFR、ER的水平,氟维司群、吉非替尼分别上调EGFR、ER的水平.结论 采用EGFR的靶向治疗与抗雌激素治疗相结合的治疗方案提高EGFR和ER阳性的EGFR-TKI获得性耐药的NSCLC的治疗效果在理论上是可行的.%Objective To investigate the antitumor effects of combination of gefitinib and fulvestrant on NSCLC cell lines with acquired resistance to gefitinib. Methods The antitumor effect of gefitinib and fulvestrant on the growth of NSCLC cell lines was ob-served at different concentrations by MTT assay. The expression levels of EGFR, ER and p-EGFR were determined by Western blot. Results ① All three lung cancer cell lines expressed both EGFR and ERs although to different extents. ② Compared with treatment of either fulvestrant or gefitinib alone, drug combination obviously decreased proliferation of H1976,H1650 and PC-9 cells lines ( P<0. 001).③Rapid activations of EGFR pathway by estrogen were observed in H1975 cells with T790M mutation.④EGFR and ERs ex-pression were down-regulated respectively in response to estrogen and EGF but up-regulated in response to fulvestrant and gefitinib in vitro. Conclusion These results suggest that there is a functional crosssignaling between the EGFR/ER pathways in NSCLC with ac-quired resistance to gefitinib, possibly providing rationale for combining gefitinib with anti-estrogen therapy for advanced NSCLC treat-ment.
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