槲皮素诱导人肺癌GLC-82细胞凋亡及机制

目的：探讨黄酮类中药成分槲皮素（Quercetin）对人肺癌GLC-82细胞生长抑制和凋亡的影响.方法：采用细胞培养技术,用不同浓度的槲皮素作用GLC-82细胞48 h,用Hoechst33258染细胞核,在荧光显微镜下观察凋亡细胞核形态变化,用QWin图像分析软件测量细胞核面积和凋亡率.采用MTT法测定细胞的生长能力.采用荧光免疫细胞化学SABC-Cy3法检测Mdm2、p53、Bax、Bcl-2和caspase-3蛋白表达,用QWin图象分析软件测定Mdm2、p53、Bax、Bcl-2和caspase-3荧光强度值.结果：槲皮素剂量依赖性的抑制GLC-82细胞生长,呈现典型的凋亡形态学特征,胞核缩小,核质浓集,呈斑块状,有凋亡小体.上调凋亡抑制因子Mdm2和Bcl-2蛋白表达,下调凋亡促进因子Bax和Caspase-3的蛋白表达,对p53蛋白表达量没有明显影响.增加Mdm2、p53、Bax、Bcl-2的阳性表达率,降低caspase-3阳性表达率.结论：槲皮素能够抑制肺癌GLC-82细胞生长并诱导细胞凋亡,而Mdm2的蛋白表达增加,可能抑制了p53发挥促凋亡作用,使部分GLC-82肺癌细胞逃避死亡.

Quercetin-Induced Cell Apoptosis in GLC-82 Human Lung Cancer Cells

Objective:To study the effects of quercetin on growth inhibition and apoptosis of GLC-82 human lung cancer cells. Methods: GLC-82 cells were cultured with different concentrations of quercetin. Growth inhibition of quercetin on GLC-82 cells was evaluated by MTT assay. Morphologic changes of quercetin-treated cells were observed by light microscope, and the nuclei stained with Hoechst33258 were visualized by fluorescence. Nuclei area and apoptotic rate were measured with QWin image processing and analysis system. The protein expressions of Mdm2, p53 , Bax, Bcl-2 and caspase-3 were analyzed by fluorescence immunocytochemical method ( SABC-Cy3 ) , and the fluorescent intensity was measured with QWin. Results: 48h after quercetin treatment, apoptotic cells increased dose-dependently. Morphological changes of GLC-82 cells showed features typical of apoptosis, including karyopyknosis, and patchy aggregation of the chromatin. The growth inhibition of GLC-82 cells was concentration-dependent. Quercetin increased the levels of Mdm2 and Bcl-2 proteins, reduced the levels of Bax and caspase-3 proteins, and had no significant effect on p53 protein. In addition, the positive rates of Mdm2, Bcl-2, Bax and p53 were elevated and that of caspase-3 was lowered. Conclusion: Quercetin may inhibit the growth and induce apoptosis of lung cancer GLC-82 cells. Upregulated expression of Mdm2 protein inhibited the pro-apoptotic effect of p53, which appeared to be responsible for reduced cell death.