二甲双胍对人肝癌Hep-G2细胞表皮生长因子及其受体表达的影响

目的 观察二甲双胍对人肝癌Hep-G2细胞表皮生长因子（EGF）及其受体（EGFR）的影响.方法 体外培养人肝癌Hep-G2细胞,用不同浓度二甲双胍进行干预,3-（4,5-二甲基噻唑-2）-2,5-二苯基四氨唑溴盐法检测二甲双胍对Hep-G2细胞生长的影响;Hoechst 33342染色荧光显微镜观察细胞的形态学变化,流式细胞术观察细胞凋亡;蛋白质印迹法（Western blot）检测EGF、EGFR的表达.结果 二甲双胍对肝癌细胞的活性具有明显的抑制作用,且呈剂量依赖性;以10 mmol/L作用终浓度抑制效果最明显,其48 h的细胞吸光度为（0.477 ±0.025）,与对照组（0.602±0.026）比较差异有统计学意义（P＜0.01）;逐渐增加二甲双胍的作用浓度,细胞凋亡率随之逐渐增加,药物组细胞凋亡率分别为（10.76±0.96）％、（20.77±1.16）％,与对照组（5.21±0.13）％相比差异均有统计学意义（P＜0.05）;Hoechst33342染色可见明显的细胞皱缩,核染色质浓缩,核碎裂等凋亡形态学变化;Western blot结果显示,EGF及其受体蛋白的表达随着二甲双胍作用浓度的增加而逐渐下调.结论 在体外,二甲双胍能够抑制人肝癌Hep-G2细胞增殖及诱导细胞凋亡,其抗肿瘤机制可能与细胞内EGF及EGFR表达下调有关.

Effects of metformin on expression of epidermal growth factor and epidermal growth factor recipient in human liver cancer cells

Objective To observe the effects of metformin on the expression of epidermal growth factor （EGF） and epidermal growth factor recipient （EGFR） in human liver cancer cell line Hep-G2.Methods In vitro,the Hep-G2 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 Hoechst 33342 and flow cytometry.The expressions of EGF and EGFR were investigated by western blot.Results Metformin inhibited the growth of Hep-G2 cells obviously in a dose-dependent manner.The absorbance was （0.477 ± 0.025）after metformin was used for 48 h,which was significandy higher than that of the control patients （0.602 ± 0.026） （P 〈 0.05）.FCM analysis showed that when Hep-G2 cells were treated with metformin,the apoptosis rates were （10.76 ± 0.96） % and （20.77 ± 1.16） %,respectively,compared with the control group （5.21 ± 0.13） % in creased （P 〈 0.05）.Cell apoptosis with cell shrinkage,nuclear chromatin concentration and fragmentation as well as the formation of apoptotic bodies were observed by cytochemical staining.The western-blot showed that the expressions of EGF and EGFR were down regulated while the concentration of metformin was increasing.Conclusion Metformin can inhibit cell proliferation and induce apoptosis in liver cancer cell line Hep-G2,which may be related to the down-regulation of EGF and EGFR protein expression.