半胱氨酸酶在NS-398诱导HepG2细胞凋亡中的作用

目的 探讨选择性环氧合酶(COX-2)抑制剂NS-398诱导肝癌HepG2细胞凋亡的分子机制。方法 采用流式细胞术测定细胞凋亡情况;Western blot法检测不同浓度NS-398处理后凋亡相关蛋白Bcl-2、Caspase3表达的变化; 并以流式细胞术检测半胱氨酸酶-3(Caspase-3) 酶活性的变化。结果 流式细胞术显示NS-398(0、100、200、300、400μmol/L)作用HepG2细胞24h后,对照处理组没有出现凋亡峰,其余各组(100、200、300、400μmol/L)出现明显的凋亡峰,其凋亡率分别为(10.51±1.04)%、(27.79±2.40)%、(45.72±3.32)%,(60.22±2.03)%(P<0.01),不同浓度NS-398处理后凋亡相关蛋白Bcl-2表达下降,Caspase-3蛋白表达增加,随着NS-398处理浓度的增加,表达活性Caspase3的细胞百分率分别为(2.67±0.22)%、(9.53±0.15)%、(21.28±0.43)%、(39.63±0.8)%、(63.40±0.69)%(P<0.01)。结论 选择性COX-2 抑制剂可能通过调节Bcl-2蛋白表达活化Caspase3,从而诱导肝癌细胞HepG2凋亡。

Significance of Caspase in NS-398 Induced Apoptosis of HepG2 Cell Line

Objective To investigate the possible role of Bcl-2 and Caspase3 in NS 398 induced apoptosis of liver tumor HepG2 cell line. Methods Cell apoptosis is determined by flowcytometry analysis using PI staining.The expression of Bcl-2 and Caspase3 protein was detected by Western blot. Caspase3 activity was evaluated by active Caspase3 apoptosis kit with flow cytometry. Results Selective COX-2 inhibitor NS-398 can significantly induce apoptosis of HepG2 cells line significantly. Flow cytometry assay revealed the apoptotic rate of HepG2 cells treated with different concentrations of NS-398 (0,100,200,300,400μmol/L) was (10.51±1.04)%,(27.79±2.40)%,(45.72±3.32)%,(60.22±2.03)%(P<0.01) respectively, while the apoptotic peak did not appear in the control group (P<0.01).The expression of Caspase3 protein was up regulated while Bcl-2 protein was down regulated,and the percentage of the cells with active Caspase3 was (2.67±0.22)%, (9.53±0.15)%, (21.28±0.43)%, (39.63±0.8)%, (63.40±0.69)% (P<0.01). Conclusion Selective COX-2 inhibitor NS-398 may activate Caspase3 by down regulating the expression of Bcl-2 protein,which causes apoptosis of HepG2 cells.