黄芩苷诱导HL-60细胞凋亡的分子机制研究

本研究旨在探讨黄芩苷对急性髓系白血病HL-60细胞增殖及凋亡的影响及其作用机制。CCK-8法检测黄芩苷对HL-60细胞增殖抑制情况;普通光学显微镜和Hoechst 33342染色后荧光显微镜下观察细胞形态学变化;流式细胞术检测细胞凋亡率;RT-PCR方法检测凋亡相关基因caspase-3、caspase-9、Bcl-2、Bax mRNA表达;Westernblot检测Bcl-2、Bax、caspase-8及caspase-3剪切片段的蛋白表达。结果表明,黄芩苷对HL-60细胞具有明显的增殖抑制作用,呈浓度和时间依赖性;在光学显微镜和荧光显微镜下细胞均呈凋亡的形态学改变;AnnexinⅤ/PI法检测到细胞早期凋亡;caspase-3、caspase-9、Bax基因mRNA表达水平呈上升趋势,Bcl-2 mRNA表达水平呈下降趋势,Bax、caspase-8及capsase-3剪切片段蛋白表达上调,同时Bcl-2蛋白表达下调,Bcl-2/Bax比值降低。结论:黄芩苷显著抑制HL-60细胞增殖并诱导其凋亡,其机制可能与降低Bcl-2/Bax比值,激活线粒体凋亡途径及死亡受体途径有关。

Molecular mechanism of HL-60 cell apoptosis induced by baicalin

This study was aimed to investigate the effect of baicalin on proliferation and apoptosis of HL-60 cells and its mechanism. Cell proliferation was assayed by using Cell Counting Kit-8. The morphological changes of HL-60 cells were examined by light microscopy and nucleolus morphological changes were observed by fluorescent microscopy after Hoechst 33342 staining. The early cell apoptosis was detected by using flow cytometry with Annexin V-FITC/PI double staining. The expression of caspase-3, caspase-9, Bcl-2 and Bax mRNA was detected by RT-PCR and Western blot assay was carried out to examine Bax, Bcl-2, caspase-8 and cleaved caspase-3 expression. The results showed that Baicalin inhibited the proliferation of HL-60 cells in a time- and concentration-dependent manner. HL-60 cells exhibited typical morphological features (for example, cell shrinkage, membrane blebbing and formation of apoptotic bodies). Cell apoptosis in early stage could be detected, the expression of caspase-3, caspase-9 and Bax mRNA was obviously up-regulated, while the Bcl-2 expression down-regulated, and accordingly Bcl-2/Bax ratio decreased. Such results were consistent with the expression of these proteins. In addition, the expression of cleaved caspase-8 protein was induced significantly after treated with baicalin. It is concluded that baicalin can significantly inhibit the proliferation of HL-60 cells and induce the apoptosis of HL-60 cells, which may occur through decreasing Bcl-2/Bax ratio by intrinsic pathway and through extrinsic pathway. It suggests that baicalin may be a promising drug for the therapy of acute myeloid leukemia.