[关键词]
[摘要]
目的 探讨蓬子菜黄酮类化合物香叶木素-7-O-β-D-木糖-(1→6)-β-D-葡萄糖苷(DXG)对人肝癌细胞株HepG2增殖的抑制作用及其诱导HepG2细胞凋亡的机制。方法 台盼蓝染色法检测DXG对HepG2细胞生长的影响;MTT法检测DXG对细胞增殖的抑制作用;吖啶橙/溴乙(AO-EB)荧光染色法观察DXG对HepG2细胞凋亡的形态学影响;琼脂糖凝胶电泳观察凋亡细胞的DNA图谱变化;反转录聚合酶链式反应(RT-PCR)检测凋亡相关基因bcl-2及bax的表达。结果 台盼蓝染色和MTT检测显示,DXG 50、100、200 μg/mL能明显抑制HepG2细胞增殖,与对照组相比差异显著(P<0.05)。AO-EB染色可见DXG诱导HepG2细胞凋亡并发生形态学改变,且随DXG的质量浓度升高,凋亡细胞的比例显著增加。琼脂糖凝胶电泳显示,HepG2细胞经DXG 100、200 μg/mL处理48 h后,可见DNA“梯形”碎片条带。RT-PCR实验表明,DXG下调细胞凋亡的抑制基因bcl-2 mRNA表达,促使凋亡基因bax mRNA表达增强。结论 DXG具有显著抑制人肝癌细胞HepG2增殖、诱导其凋亡的作用,其作用机制与调控bax/bcl-2的表达有关。
[Key word]
[Abstract]
Objective To investigate the inhibition of cell proliferation and induction of apoptosis of flavonoids [diosmetin-7-O-β-D- xylopyranosyl-(1→6)-β-D-glucopyranoside, DXG)] from Gallium verum on liver cancer cell HepG2 and to study its mechanisms. Methods Cell growth was detected with Trypan blue staining. The proliferation inhibition rates of DXG on HepG2 were measured by MTT assay. The morphology changes of apoptotic cell were obserbed by AO-EB double staining. Agarose gel electrophoresis was used to detect the DNA fragmentation. The expression of apoptosis-related genes bax and bcl-2 was examined by RT-PCR. Results DXG (50, 100, and 200 μg/mL) could significantly inhibit the proliferation of HepG2 cells by Trypan blue staining and MTT assay compared with the control group (P < 0.05). AO-EB double staining showed that DXG could induce the apoptosis and morphological change of HepG2 cells and the ratios of apoptosis were obviously high when the concentration of DXG increased. The laddering pattern was clearly presented in the cells treated with 100 and 200 μg/mL DXG for 48 h. RT-PCR showed that DXG could up-regulate the mRNA level of bax and down-regulate the mRNA levels of bcl-2 in HepG2 cells. Conclusion DXG could obviously inhibit the proliferation and induce the apoptosis in HepG2 cells. The mechanism is related to the modulation of the expression level of bax/bcl-2 mRNA.
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[基金项目]
国家自然科学基金资助项目(201281274034);教育部博士点基金资助项目(20112327110006)