c-Met在人非小细胞肺癌A549细胞系中表达活性与放疗抵抗的关系

目的:探讨c-Met对A549人非小细胞肺癌细胞系的放疗抵抗作用及发生机制.方法:采用人肺癌细胞系A549体外培养作为研究对象.将经不同浓度c-Met抑制剂处理后的A549细胞经或不经X线照射,用Western blot法检测c-Met及c-Src蛋白磷酸化形式表达水平,观察不同浓度c-Met抑制剂对c-Met和c-Src蛋白活性的抑制作用,同时用MTT法检测不同处理组细胞增殖抑制情况,流式细胞仪(FCM)检测不同处理组的细胞凋亡情况.结果:X线照射可使A549细胞系c-Met及c-Src磷酸化水平升高(P＜0.05),经或不经X线照射c-Met抑制剂(PHA665752)均可使c-Met及c-Src磷酸化水平降低,即有效抑制其蛋白活性表达(P＜0.05).MTT法及流式细胞法检测结果显示c-Met蛋白活性表达得到有效抑制后,A549细胞经X线照射后增殖抑制率及凋亡率较单纯放疗时明显增高(P＜0.05).结论:X线照射后c-Met信号通路活化使A549人非小细胞肺癌细胞系产生放疗抵抗,c-Src可能位于c-Met信号通路下游共同参与放疗抵抗,有效抑制c-Met蛋白活性表达可提高A549细胞放疗敏感性,其机制与抑制细胞增殖及诱导细胞凋亡有关.

The relationship between the c-Met expression activity and the radioresistance in human non-small cell lung cancer cell lines A549

Objective:To explore the radioresistance efficacy of c-Met on human NSCLC cell lines A549 and the mechanism.Methods:We used A549 cell lines in vitro as research obsject.By adding different concentrations of c-Met inhibitors to A549 cell lines.After X-ray radiation,Western blot assay was used to detect the phosphorylated protein expression level of c-Met and c-Src,to observe the inhibitory effects of different concentrations of c-Met inhibitor on c-Met and c-Src activity before and after X-ray radiation.At the same time,MTT reduction assay was used to evaluate the inhibition rate of different treatment groups.The cell apoptosis of different treatment groups was investigated using FCM.Results:X-ray radiation can increase the level of phosphorylated c-Met in A549 cell lines (P =0.004 0),c-Met inhibitor PHA665752 decreased the phosphorylation level of c-Met before and after X-ray radiation,that effectively inhibited the protein expression of c-Met (P ＜ 0.05).X-ray radiation can increase the level of phosphorylated c-Src in A549 cell lines (P =0.001 8),PHA665752 inhibited the activation of c-Src expression before and after the X-ray radiation at the same time (P ＜ 0.05).MTT assay and FCM detection results show that after the expression of c-Met protein activity was inhibited effectively,the proliferation inhibition rate and apoptosis rate of A549 cell lines after X-ray radiation increased obviously compared with X-ray radiation alone (P ＜ 0.05).Conclusion:Activation of c-Met signal pathway after X-ray radiation is the important reason of radioresistance in human NSCLC cell lines A549,c-Src may be located on the downstream of c-Met signal pathway,that mediated radioresistance together.Effectively inhibit the activation of c-Met expression can increase the radiosensitivity of A549 cells,the mechanism may be related with the inhibition of cell proliferation and the induction of apoptosis.