EGF及其受体在二甲双胍抑制人肝癌细胞增殖中的作用

Effect of metformin on expression of EGF and EGFR in hepatocellular carcinoma cells

目的观察二甲双胍对人肝癌SMMC-7721细胞表皮生长因子（EGF）及其受体（EGFR）的影响。方法用不同浓度二甲双胍作用于体外培养的人肝癌SMMC-7721细胞后，MTT法检测药物对肝癌细胞增殖的抑制情况；流式细胞仪及Hoechst33342染色荧光显微镜观察细胞凋亡；免疫印迹法检测EGF及EGFR的表达。结果二甲双胍能明显抑制肝癌细胞的生长增殖，且呈剂量依赖性；流式细胞仪检测显示：随着二甲双胍作用浓度的增加，细胞凋亡率逐渐增加，二甲双胍实验组细胞凋亡率分别为（10．76±0．96）％、（20．77±1．16）％，Hoechst33342染色可见凋亡细胞皱缩，核染色质浓缩，核碎裂，亦可见典型的凋亡小体；western-blot显示：随着二甲双胍作用浓度的增大，EGF及EGFR表达逐渐下调。结论二甲双胍可抑制人肝癌细胞SMMC-7721的增殖，并促进其凋亡，其机制可能与下调细胞内EGF及EGFR的表达有关。

Objective To observe the effect of metformin on the expression of EGF and EGFR in human liver cancer cell line SMMC-7721. Methods In vitro, the SMMC-7721 cells were treated with different concentrations of metformin, the proliferation of the cells was detected by MTT assay, and the apoptosis of the cells was measured by cytochemical staining with Hoechst33342 and flow cytometry. The expression of EGF and EGFR were investigated by western blot. Results Metformin inhibited the growth of SMMC-7721 cells obviously in a dose-dependent manner. FCM analysis showed that when SMMC-7721 cells were treated with mefformin, the apoptosis rate for 48 h was （10. 76 ± 0. 96 ）%, （20. 77 ± 1.16） %, respectively. Cell apoptosis with cell shrinkage, nuclear chromatin concentration and fragmentation as well as the formation of apoptotic bodies were observed by eytochemical staining when treated with mefformin. The western-blot showed that the expressions of EGF and EGFR were down regulated while the concentration of mefformin was increasing. Conclusions Metformin can inhibit cell proliferation and induce apoptosis in liver cancer cell line SMMC-7721, which may be related to the down-regulation of EGF and EGFR protein expression.