中文摘要：

目的：探讨沉默EZH2基因表达对胆管癌QBC939细胞增殖的抑制作用及其机制。方法：设计并合成靶向EzH2的siRNA体外转染QBC939细胞，以实时荧光定量PCR和Western Blot法检测mRNA及蛋白表达水平，通过MTT法和平板克隆实验检测细胞增殖能力，流式细胞术检测细胞凋亡及周期分布，β－半乳糖苷酶染色法检测细胞衰老情况，以Western Blot法检测H3K27me3、P14ARF、P16INK4a、P53、P21、E2F1蛋白表达变化。结果：靶向siRNA可有效沉默EZH2表达，显著抑制细胞体外增殖能力。与对照组相比，实验组细胞G1／S期比值显著升高，出现G1期阻滞，而凋亡率未见明显差异；β－半乳糖苷酶染色阳性，呈衰老特征；衰老通路的P14ARF、P16INK4a、P53、P21蛋白表达上调，而H3K27me3、E2F1蛋白表达下调。结论：沉默EZH2表达可显著抑制QBC939细胞的体外增殖能力，其机制可能与调控衰老通路有关。

英文摘要：

Objective To investigate the inhibitory effects of silencing expression ofEZH2 gene on the cell proliferation of human QBC939 ceils and its mechanisms. Methods The targeting siRNA was designed and transfected into QBC939cells. The expressions of EZH2 mRNA and protein were detected by real-time qPCR and western blotting, respectively. The ability of eellproliferationwas analyzed by MTT assay and plate clone formation assay. Cell apoptosis and cycle percentage weremeasured by flow eytometry. Cell senescence was assessed byβ-galactosidase dyeing.The expressions of H3K27me3, P14ARF, P16INK4a, P53, P21 and E2FI proteinwere determined by Western blotting.ResuhsCompared with the control group, the expressions of mRNAand protein were significantly elevated in experimental group. The ability of eellproliferation in the experiment group was significantly down regulated, which could also cause a rise of G1/S phase, hut not a marked variation of apoptosis rate. Silencing EZH2 would induce a obvious senescence phenotype in QBC939 cells. EZH2-siRNA transferredeould also down-regulate the expressions of H3K27me3 and E2F1 protein, while up-regulating the expressions of P14ARs, P16INK4a, P53 and P21 protein in QBC939 cells.Conclusions Silencing EZH2 could induce a significant inhibition on cell proliferation of QBC939 cells, the mechanism of which may be associated with the senescence pathway regulation.