西兰花多肽组分Ⅱ诱导神经胶质瘤细胞凋亡的作用及其机制研究

Effect of component Ⅱ of broccoli polypeptide on glioma cell apoptosis

目的:探讨西兰花多肽组分II诱导胶质瘤细胞凋亡的作用及机制。方法:培养人神经胶质瘤SHG-44细胞,将其分为对照组以及3、10、30和100 mg/L西兰花多肽组分II组,MTT法检测西兰花多肽组分II作用后细胞活力的变化;Annexin V/PI检测细胞的凋亡率;倒置显微镜观察西兰花多肽组分II诱导细胞凋亡的形态学变化;免疫细胞化学和Western blotting法检测西兰花多肽组分II作用后Bax、Bcl-2蛋白表达,Western blotting法检测caspase-3蛋白表达。结果:西兰花多肽组分II作用SHG-44细胞24 h、48 h和72 h时均可以降低细胞活力,作用呈时间-剂量依赖性。Annexin V/PI检测细胞凋亡率发现,各用药组细胞凋亡率随着药物剂量的增加而显著升高。倒置显微镜下观察,西兰花多肽组分II作用SHG-44细胞72 h后,各用药组细胞的密度随药物浓度升高而明显降低,并可见到明显的凋亡小体。细胞免疫组织化学和Western blotting结果显示,药物作用SHG-44细胞72 h后,与对照组比较,细胞Bax蛋白表达呈上升趋势,Bcl-2蛋白表达呈下降趋势,各用药组Bax/Bcl-2比值均明显增加(P<0.05或P<0.01);Western blotting检测caspase-3蛋白发现,各药物组caspase-3蛋白表达量均增加,与空白对照组比较,30和100 mg/L西兰花多肽组分II组差异有统计学意义(P<0.01)。结论:西兰花多肽组分II可提高神经胶质瘤细胞中Bax/Bcl-2蛋白的比值,促进caspase-3蛋白活化,从而诱导肿瘤细胞凋亡。

AIM： To explore the effect of component II of broccoli polypeptide on the apoptosis in glioma cells.METHODS： Human glioma SHG-44 cells were cultured and divided into control group and 3,10,30 and 100 mg /L component II of broccoli polypeptide groups. Cell viability was detected by MTT assay. The apoptotic rates were examined by Annexin V /PI staining. The morphological changes of the cells were observed under inverted microscope. The protein expression of Bax and Bcl-2 was detected by immunocytochemistry and Western blotting. The protein level of caspase-3 was also examined by Western blotting. RESULTS： Treatment with component II of broccoli polypeptide for 24 h,48 h or 72 h induced significant inhibition of viability of SHG-44 cells in a time- and dose-dependent manner. The results of Annexin V /PI staining showed that the apoptotic rates were increased in treatment groups in a dose-dependent manner. The density of glioma cells was decreased after treated with increasing concentrations of the drug,and the apoptotic bodies were observed under inverted microscope at 72 h. The results of immunocytochemistry and Western blotting showed that the expression of Bax protein was increased but Bcl-2 protein expression was decreased,and the ratio of Bax /Bcl-2 was increased significantly compared with control group（ P 〈0. 05 or P〈 0. 01）. The level of caspase-3 protein was increased in 30 and 100 mg /L component II of broccoli polypeptide groups compared with control group（ P〈 0. 01）. CONCLUSION： The component II of broccoli polypeptide increases the ratio of Bax /Bcl-2 and activates caspase-3 protein,thus inducing the apoptosis of glioma cells.