不同浓度洋地黄对人乳腺癌MDA-MB-231细胞增殖和凋亡的影响

目的:研究不同浓度洋地黄对体外培养的人乳腺癌细胞株MDA-MB-231增殖和凋亡的影响，并探讨其可能机制。方法:取对数生长的细胞，不同浓度洋地黄处理，MTT法观察洋地黄对MDA-MB-231细胞活性、增殖的影响；Hoechst 33342染色观察洋地黄促细胞凋亡作用，细胞色素C含量及caspase 9活性变化检测线粒体损伤程度；生长曲线法观测洋地黄对细胞增殖的影响，Western blot检测细胞周期蛋白表达。结果:高浓度的洋地黄（≥100nmol/L）引起MDA-MB-231细胞凋亡，促进细胞色素C释放，增加caspase 9活性。低浓度洋地黄（30nmol/L）不引起肿瘤细胞凋亡，但是抑制细胞增殖，抑制细胞周期素D1和细胞增殖抗原PCNA的表达，增强p21cip1蛋白的表达。结论:高浓度洋地黄通过线粒体损伤通路促进乳腺癌细胞凋亡，低浓度洋地黄通过干扰细胞周期抑制乳腺癌细胞的生长。

Effect of different concentration ouabain on cell proliferation and apoptosis in MDA-MB-231 breast cancer cells

Objective：To investigate the effect of ouabain on MDA-MB-231 cell proliferation and apoptosis, and analyze the underlying mechanism. Methods：Normal cultured MDA-MB-231 cells were treated with different dose of ouabain. MTT assay was used to detect cell viability. Hoechst 33342 staining,cytochrome C protein level and caspase 9 activities were used for determine cell apoptosis and mitochondrial injury. Cell growth curve was used for detecting cell proliferation,Western blot was used for determine proteins that control cell cycle progress. Results：High dose of ouabain（≥100nmol/L）induced MDA-MB-231 cell apoptosis,increased cytosolic cytochrome C expres-sion and enhanced caspase 9 activity. Low dose of ouabain（30nmol/L）had no significant effect on cell apoptosis,but inhibited cancer cell growth. 30nmol/L ouabain induced low expression of PCNA,cyclin D1 and high expression of p21cip1. Conclusion：High dose ouabain induced MDA-MB-231 cancer cell apoptosis via mitochondrial injury, whereas low dose ouabain only induced cancer cell growth arrest via interfere cell cycle progress.