氧化苏木素诱导人乳癌MCF-7细胞凋亡及其作用机制

Brazilein Induced Cells Apoptosis in Human Breast Cancer MCF-7 Cells and Its Action Mechanism

【目的】探讨氧化苏木素对人乳癌MCF-7细胞的凋亡作用及其相关作用机制。【方法】MTT实验检测氧化苏木素对MCF-7细胞和正常乳腺上皮细胞MCF10A的细胞毒作用;AnnexinV/PI双染,流式细胞仪检测细胞凋亡的发生;荧光染料DiOC6染色,流式细胞仪检测细胞内线粒体膜电位的变化;Westernblot实验检测细胞浆细胞色素C及细胞内caspase-9和survivin蛋白的变化。【结果】氧化苏木素对人乳癌MCF-7细胞具有高效的细胞毒作用,而对正常乳腺上皮MCF10A细胞毒性较弱,IC50值分别为(7.15±0.43)μmol/L和(33.56±2.87)μmol/L;0、7.5、15、30μmol/L的氧化苏木素处理MCF-7细胞48h后,细胞的凋亡率从(3.37±0.66)%依次升高到(16.8±1.27)%、(31.31±4.22)%、(51.23±5.55)%;DiOC6染色流式细胞仪检测结果显示氧化苏木素可以剂量依赖性地降低线粒体膜电位;Westernblot结果显示氧化苏木素诱发了线粒体内细胞色素C的释放和细胞内caspase-9蛋白的剪切激活,同时氧化苏木素也可剂量依赖性地降低survivin蛋白的表达。【结论】氧化苏木素可通过线粒体通路诱导MCF-7细胞凋亡,下调survivin蛋白可能是其诱导细胞凋亡的主要机制。

[Objective] To study the cytotoxic activity of brazilein against human breast cancer MCF-7 cells and its action mechanism.[Methods] MTT assay was used to detect the cytotoxic activity of brazilein against MCF-7 cells and immortalized breast epithelial MCF10A cells.The apoptosis was determined by Annexin V-FITC/PI staining and flow cytometry analysis.Mitochondrial membrane potentia was indicated by DiOC6 staining.The Western blotting was performed to detect wanted protein.[Results] Brazilein exerted potent cytotoxicity to human breast cancer MCF-7 cells,and the IC50 values was（7.15 ± 0.43） μmol/L.However,the IC50 values of brazilein against the MCF10A cells was（33.56 ± 2.87） μmol/L.After treatment with 0,7.5,15,30 μmol/L brazilein for 48 h,the percent of apoptosis was elevated from（3.37 ± 0.66）% to（16.8 ± 1.27）%,（31.31 ± 4.22）%,（51.23 ± 5.55）%,respectively.Brazilein decrease the level of mitochondrial membrane potentia in a dose-dependent manner,as detected by DiOC6 staining.Western blotting showed that brazilein released cyto-c to cytoplasm and following cleaved caspase-9 protein.The further study showed that brazilein down-regulated survivin in protein level by Western blot analysis.[Conclusion] Brazilein induced apoptosis though a mitochondria-dependent pathway,and which was related to the down-regulation of survivin protein.