NF-κB与Caspase-9在大豆异黄酮诱导人乳腺癌细胞凋亡中的作用

Effects of NF-κB and Caspase-3 on Soy Isoflavone-induced Apoptosis in Breast Cancer MCF-7 Cells

目的探讨核转录因子NF-κB和Caspase-9在大豆异黄酮诱导人乳腺癌细胞MCF-7细胞凋亡的作用和可能的机制。方法大豆异黄酮处理MCF-7细胞后,采用流式细胞仪检测乳腺癌细胞凋亡、线粒体心磷脂的变化,及免疫荧光显微技术检测线粒体中细胞色素c释放情况;并应用酶联免疫吸附方法检测了细胞凋亡中Caspase-9及NF-κB活性变化。结果 80mg/L大豆异黄酮处理乳腺癌MCF-7细胞24h后,细胞发生凋亡,凋亡率为7.56%;随时间的延长凋亡率不断上升,与对照组比较差异有统计学意义(P<0.01);同时,细胞线粒体心磷脂丢失增多,即大豆异黄酮处理组中心磷脂含量降低的凋亡细胞所占比例为(21.33±5.38)%,高于对照组(4.34±1.85)%,差别有统计学意义(P<0.01)。大豆异黄酮处理后,线粒体细胞色素c释放增多,Caspase-9活性增加,24h其活性为(13.65±3.42)μmol(/L·h·mg)蛋白,并随时间的延长而增加。经大豆异黄酮处理后,乳腺癌细胞NF-κB活性被抑制,24hNF-κB活性为0.19±0.03,低于对照组0.21±0.02,差别有统计学意义(P<0.05)。结论大豆异黄酮触发了线粒体途径而诱导肿瘤细胞凋亡,其可能机制为引发线粒体心磷脂丢失,造成线粒内膜损伤,导致细胞色素c释放和Caspase-9激活,同时抑制NF-κB活性,最终诱导细胞发生凋亡。

Objective To explore the effect of NF-κB on soy isoflavone （SI）-induced apoptosis in breast cancer MCF-7 cells. Methods Human breast cancer cell lines （MCF-7） were treated with SI, and then, cell apoptosis, mitoehondrial cardiolipin （CL） were detected through Flow Cytometry. In addition, the release of cytochrome c was measured by Immunofluorescence Microscopy. Finally, the method of ELISA was utilized to study the activity of Caspase-9 and NF-κB. Results There was significant apoptosis （the rate was 7.56%） occurred in MCF-7 cells treated with 80mg/L SI fro 24 hrs, while, the decrease in the formation of mitochondrial cardiolipin was detected too, the ratio of apoptosis cells with decreased cardiolipin in SI treated group （21.33±5.38%） was higher than that in the control （4.34±1.85%）, （P〈0.01）. Besides, SI could promote the release of eytochrome c, thus enhance the activity of caspase-9. On the other hand, the activity of NF-κB decreased in MCF-7 cells treated with SI than in the control （0.19±0.03 vs 0.21±0.02） （P〈0.05）. Conclusion Soy isoflavone could induce tumor cells apoptosis through initiating mitoehondrial pathway. After mitoehondrial damaged, cytochrome c was released, Caspase-9 was activated and the activity of NF-κB was inhibited as well.