冬虫夏草对乳腺癌细胞凋亡的诱导及相关基因表达的调控

Effects of cordyceps sinensis on induction of apoptosis and regulation of apoptosis related genes in breast cancer cell

目的:明确中药冬虫夏草(cordyceps sinensis,CS)对人乳腺癌细胞凋亡的影响及凋亡相关基因表达的调控。方法:应用MTT比色法检测CS对乳腺癌细胞的增殖抑制作用;应用流式细胞仪、DNA琼脂糖凝胶电泳法检测细胞凋亡;采用免疫组化法检测凋亡相关基因Bcl-2、Bax表达水平的改变。结果:CS对人乳腺癌细胞株MCF-7生长有抑制作用,且呈时间/浓度依赖性;CS使MCF-7细胞发生细胞凋亡,流式细胞仪DNA直方图上出现了凋亡峰,且凋亡率呈浓度依赖性;细胞NDA裂解成180～200bp及其倍数的片段,电泳得到特有的梯形条带;随着药物浓度的增加,Bcl-2表达逐渐减弱,Bax表达逐渐增强。结论:CS可诱导乳腺癌细胞凋亡,为CS的抗肿瘤应用提供了理论依据,CS可能通过调控Bcl-2、Bax基因表达而诱导凋亡。

Objective： To investigate whether cordyceps sinensis （CS） can induce apoptosis of breast cancer cell line and elucidate the regulation of CS on Bcl-2 family genes. Methods： MTT assay was used to measured the anti-proliferative effect of CS. Cell cycle and apoptosis of MCF-7 cells were analyzed by flow cytometry （FCM）. Apoptosis induction was also proved by agarose gel electrophoresis. Alteration of protein of Bcl-2 and Bax genes was detected by immunohistochemical techniques. Results： CS could inhibit the growth of MCF-7 cells in a dose/time dependent manner. MCF-7 cells appeared noteble apoptosis after incubated with CS, an apoptotic peak appeared in DNA histogram of FCM, the apoptotic rate of cells was dose dependent, too. After treating with CS, a fragmented DNA ladder was observed by agarose gel electrophresis. The Bax protein kept increasing during CS treatment,while the Bcl-2 protein kept decreasing, and the tendency was more obvious in 10-50 μg/ml. Conclusion： CS can induce apoptosis of MCF-7 breast cancer cells, which supply a futher theoretical foundation to the anti-cancer use of CS. One of the major pathways that mediated the anti-tumor response of CS in breast cancer cells is through down-regulation of protein expression of Bcl-2 genes and up-regulation of protein expression of Bax genes.