酪酸梭菌诱导结肠癌SW-480细胞凋亡及作用机制

Apoptosis of colon cancer SW-480 cells induced by clostridium butyricum and its mechanism

目的探讨酪酸梭菌(Clostridium butyricum,CB)诱导人结肠癌SW-480细胞凋亡的作用及机制。方法采用不同浓度的酪酸梭菌(1.5×103、1.5×104、1.5×105、1.5×106、1.5×107、1.5×108CFU/mL)在不同作用时间(24、48、72、96 h)处理结肠癌SW-480细胞后,CCK8法检测CB对SW-480细胞的增殖抑制。电镜观察CB对SW-480细胞形态的影响。Annexin V-FITC/PI双标法检测细胞凋亡。Caspase试剂盒检测SW-480细胞中Caspase-3和Caspase-9的活性。Western blot法检测SW-480细胞Bax和Bcl-2凋亡蛋白表达的变化。结果酪酸梭菌对SW-480细胞的生长抑制作用呈明显的时间-剂量依赖性;菌液浓度为1.5×107CFU/mL和1.5×108CFU/mL的酪酸梭菌处理后的SW-480细胞形成典型的凋亡小体;酪酸梭菌(1.5×107CFU/mL和1.5×108CFU/mL)处理能显著增强SW-480细胞Caspase-3和Caspase-9的活性,促进SW-480细胞凋亡(P<0.01);随着菌液浓度的增加,凋亡蛋白Bax的表达增强,而抑凋亡蛋白Bcl-2的表达减弱。结论酪酸梭菌可诱导SW-480细胞凋亡,其作用机制与凋亡相关基因Bax、Bcl-2和caspase-3、caspase-9的表达有关。

Objective To investigate the effects and mechanism of Clostridium butyricum （CB）-induced apoptosis in human colon cancer cell line SW-480. Methods SW-480 cells were treated with CB at different concentrations of 1.5×103, 1.5×104, 1.5×105, 1.5×106, 1.5×107, and 1.5×108CFU/mL for different time （24, 48, 72, or 96 h）. Cell viability was tested by CCK-8 assay. Cell morphology was examined by electron microscopy. Annexin V-FITC/PI double-staining was performed to detect cell apoptosis. The activities of Caspase-9 and Caspase-3 were measured by Caspase assay kit. The protein expression of Bcl-2 and Bax was detected by Western blotting. Results The inhibitory effect of CB on SW-480 cells showed a significant time-dose fashion. CB with the bacterial concentration of 1.5×107 and 1.5×108 CFU/mL induced typical apoptotic bodies, increased the activities of caspase-9 and caspase-3, and promoted apoptosis in SW-480 cells （P〈0.01）. With the increase of bacterial concentration, the expression of apoptotic protein Bax was enhanced and that of the anti-apoptotic protein Bcl-2 was decreased. Conclusion CB effectively induces apoptosis of SW-480 cells, which may involve the expression regulation of apoptosis-related genes Bcl-2, Bax, Caspase-9, and Caspase-3.