肝细胞生长因子拮抗放线菌素D诱导的肝细胞凋亡及机制探讨

Hepatocyte growth factor protects hepatocytes from apoptosis induced by actinomycin D

目的:探讨肝细胞生长因子(HGF)对放线菌素D(ActD)诱导HL7702肝细胞凋亡的拮抗作用及可能机制。方法:本实验采用HL7702正常人肝细胞株,MTT法检测ActD对肝细胞存活力的影响;Hoechst33342进行凋亡形态学染色;DNA凝胶电泳及流式细胞仪检测细胞凋亡数量;Western blotting方法检测细胞总Akt及磷酸化Akt蛋白的表达。结果:ActD可以诱导HL7702肝细胞凋亡,其浓度在0.25-8 mg/L范围内呈现剂量效应关系;PI3K特异性抑制剂wortmannin能够增强ActD诱导的肝细胞凋亡作用;肝细胞生长因子(HGF)对ActD诱导的肝细胞凋亡有拮抗作用,在一定剂量范围内呈现剂量效应关系;并且HGF能够激活PI3K/Akt信号转导途径;进一步用wortmannin阻断PI3K/Akt信号途径后,HGF的拮抗凋亡作用被抑制。结论:一定剂量的ActD可以诱导肝细胞凋亡;wortmannin能够增强ActD诱导肝细胞凋亡的作用;HGF对ActD诱导的这种细胞凋亡有明显的拮抗作用,并且HGF的抗凋亡作用与其激活细胞内PI3K/Akt信号转导通路有关。

AIM： To investigate the anti - apoptotic effect of hepatocyte growth factor （HGF） on actinomycin D （ActD） - induced apoptosis in hepatocytes and the possible pathway. METHODS： Hepatocytes were exposed to ActD and HGF. The cytotoxic effects of ActD were tested by MTT. Apoptotic cells were identified by Hoechst 33342 staining, flow cytometry and detection of DNA fragmentation with agarose gel. Akt and phospho - Akt were detected by Western blotting analysis. RESULTS： The results showed that ActD induced apoptosis in hepatocytes 5 h after treatment. Phosphatidylinositol - 3 kinase （PI - 3K） specific inhibitor wortmannin enhanced the apoptotic effect of ActD. Furthermore, HGF significantly reduced the apoptosis in hepatocytes induced by ActD in a concentration- dependent manner. In the presence of wortmannin, HGF did not overcome apoptosis. CONCLUSION： Wortmannin enhances the apoptotic effect of ActD. HGF protects hepatocytes from apoptosis induced by ActD through a PI3K/Akt pathway.