牡荆素对人肝细胞癌SMMC-7721细胞的增殖抑制作用及其机制的影响

目的: 研究牡荆素(vitexin)对人肝癌细胞SMMC-7721的增殖抑制作用, 并初步探讨其作用机制。方法: 体外培养人肝癌细胞SMMC-7721, 分别采用MTT法和Hoechst33258核染色法检测牡荆素对人肝癌细胞SMMC-7721活力的影响以及观察细胞形态学变化;流式细胞仪检测细胞凋亡率和线粒体膜电位(ΔΨm) 变化;蛋白免疫印迹法检测p53、Bcl-2、Bax等相关凋亡蛋白水平的表达情况。结果: 牡荆素培养人肝癌细胞SMMC-7721 48, 72, 96 h后能明显抑制细胞增殖, 呈时间-剂量依赖性(P<0.05), 其IC₅₀分别是150.37, 116.24, 90.19 μmol·L^-1。牡荆素作用于人肝癌细胞SMMC-7721 72 h后, 以浓度依赖性方式增加细胞凋亡率、降低线粒体膜电位(ΔΨm) 以及上调p53、Bax、Caspase-3等相关促凋亡蛋白的表达, 下调Bcl-2抗凋亡蛋白的表达。结论: 牡荆素能抑制人肝癌细胞SMMC-7721增殖诱导凋亡, 呈时间-剂量依赖性, 其作用机制可能通过依赖P53途径下调Bcl-2, 上调Casepase-3、Bax、P53、PARP等基因表达, 进而诱导凋亡有关。

Inhibiting effects and mechanism of vitexin against proliferation of SMMC-7721 cancer cells

OBJECTIVE To investigate anti-proliferative effects of vitexin against human hepatocelluar carcinoma cell line SMMC-7721 in vitro and its molecular mechanism.METHODS SMMC-7721 cells were cultured in vitro, cytotoxic effects of drugs and morphological changes of SMMC-7721 cells were measured by MTT assay and Hoechst33258, respectively. Cell apoptosis and mitochondrial membrane potential (ΔΨm) were identified by flow cytometry (FCM). Expression levels of p53, Bcl-2, Bax and other apoptosis-related proteins were analyzed by Western Blot analysis.RESULTS Vitexin incubation for 48, 72 and 96 h resulted in significant inhibition of SMMC-7721 cell proliferation in a dose and time dependent manner (P<0.05), and IC₅₀ values for them were 150.37, 116.24 and 90.19 μmol·L^-1, respectively. Rate of apoptotic SMMC-7721 cells was increased and accompanied by a decrease of Δφm level in a concentration-dependent manner after treating with vitexin for 72 h. Expression levels of p53, Bax, Casepase-3 and related proapoptotic proteins were upregulated, anti-apoptotic protein Bcl-2 was downregulated, all in a concentration-dependent manner. CONCLUSION Vitexin can potently disturb proliferation of SMMC-7721 cells in vitro and induce apoptosis in a concentration and time dependent manner, through mechanisms of up-regulating expression levels of casepase-3, Bax, P53 and PARP, and down-regulating expression levels of Bcl-2 by P53-dependent apoptotic pathway.