Background and objective: It has been known that hepatocyte growth factor (HGF) induces gefitinib resistance in non-small cell lung cancer (NSCLC) cells. The possible mechanism may be related to the activation of the HGF receptor c-Met. The aim of this study is to investigate the involvement of c-Met and its downstream signaling pathway in the HGF-induced gefitinib resistance of NSCLC cells with different epidermal growth factor receptor (EGFR) gene types.
Methods: NSCLC cell lines with different EGFR genes (PC-9, PC9/R, H292, and A549) were selected and induced by HGF. Cell survival was determined by MTT assay and the expression of Met and downstream signaling proteins were examined by Western blot.
Results: Gefitinib inhibited the cell growth of PC9, H292, and A549 cell lines in a dose-dependent manner. The concentration-survival curve notably shifted to the right when induced by HGF. The apoptotic rate was lower when the cells were treated with HGF and gefitinib than when these cells were treated with gefitinib alone (P<0.05), particularly in PC9, H292, and A549 cells, but not in PC9/R. HGF stimulated the phosphorylation of Met and downstream signaling proteins in PC9, H292, PC9/R, and A549 cell lines. p-Met, p-Akt, p-Stat3, and p-Erk1/2 expressions were higher when the cells were treated with HGF and gefitinib than when these cells were treated with gefitinib alone, particularly in PC9, H292, and A549 cells, but not in PC9/R.
Conclusions: c-Met and its downstream signaling pathway possibly participated in the HGF-induced gefitinib resistance in NSCLC cells with different EGFR gene types.
背景与目的 肝细胞生长因子（hepatocyte growth factor, HGF）诱导非小细胞肺癌（non-small cell lung cancer, NSCLC）对吉非替尼耐药，可能与其受体c-Met激活有关。本研究旨在探讨c-Met及其下游信号通道是否参与HGF诱导不同基因型NSCLC细胞株对吉非替尼耐药。方法 选择人NSCLC细胞株表皮生长因子受体(epidermal growth factor receptor, EGFR)突变型PC-9、PC9/R和EGFR野生型H292、A549，用HGF诱导细胞，通过MTT法检测细胞增殖，Annexin V-FITC法检测细胞凋亡，应用免疫印迹技术检测细胞中c-Met及下游通道的变化。结果 吉非替尼对PC9、H292、A549的生长抑制作用呈浓度依赖性，HGF诱导后吉非替尼抑制细胞的生长曲线明显往右移 。在PC9、H292、A549细胞中，吉非替尼和HGF处理组的细胞凋亡率比吉非替尼处理组均减少（P<0.05），在PC9/R细胞中无明显减少（P>0.05）。HGF能激活PC9、H292、PC9/R、A549细胞中c-Met及其下游通道蛋白。在PC9、H292、A549细胞中，吉非替尼和HGF处理组的p-Met、p-Akt、p-Stat3、p-Erk1/2蛋白表达比吉非替尼处理组均增高，在PC9/R细胞中无明显增高。结论 在体外HGF诱导不同基因型NSCLC细胞株对吉非替尼耐药，c-Met及其下游信号通道参与HGF诱导不同基因型NSCLC细胞株对吉非替尼耐药。