中文摘要：

目的：研究蟾毒灵（ bufalin）对TRAIL诱导乳腺癌MDA-MB-231细胞凋亡的的影响及机制。方法：MTT法测定细胞活力、采用流式细胞仪检测细胞凋亡，免疫荧光实验检测DR4、DR5的表达情况，Western blot法检测c-Flip和XIAP蛋白的表达。结果：MTT结果显示bufalin作用于MDA-MB-231细胞后24h和48h的IC50分别为934nmol/L 和513nmol/L。流式分析显示50nmol/L 的 bufalin 作用24h 仅诱导4.5%的MDA-MB-231细胞凋亡，100ng/ml的TRAIL作用24h诱导5.1%的MDA-MB-231细胞凋亡，50nmol/L的bufalin与100ng/ml的TRAIL联合作用24小时后可诱导32.5%的MDA-MB-231细胞凋亡。Western blot分析显示bufalin与TRAIL联合作用后导致c-Flip和XIAP的明显下调。结论：Bufalin可通过下调c-FLIP和XIAP的表达增强TRAIL诱导的乳腺癌MDA-MB-231细胞凋亡。

英文摘要：

To investigate the effect of bufalin on TRAIL-induced apoptosis,and explore the possible mechanism. Methods：Cells proliferation was measured using MTT assay. Cells apoptosis was determined by flow cy-tometry. Expression of c-Flip and XIAP was analyzed by Western blot. Results：Bufalin could surppress the profera-tion of MDA-MB-231 cells. The 24h and 48h IC50 were 934nmol/L and 513nmol/L,respectively. Flow cytometry a-nalysis showed that 100ng/ml of TRAIL induced 5. 1% apoptosis in MDA - MB -231 cells after 24h. Bufalin （50nmol/L）induced only 4. 5% apoptosis after 24h. In contrast,treatment with bufalin＋TRAIL increased the apop-totic fraction from 5. 1% to 32. 5%. Further analysis showed that bufalin treatment significantly down-regulated the expression of c-Flip and XIAP. Conclusion：Bufalin enhanced TRAIL-induced breast cancer MDA -MB -231 cells apoptosis through down-regulating the expression of c-Flip and XIAP.