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目的:研究Zeste基因增强子同源物2(EZH2)在人多发性骨髓瘤细胞系RPMI8226中的作用和分子机制。方法:采用实时定量反转录聚合酶链反应(RT-qPCR)法检测3株人多发性骨髓瘤细胞和20名多发性骨髓瘤患者骨髓单个核细胞中EZH2的表达水平。以RPMI8226细胞为代表，采用小干扰RNA(siRNA)沉默EZH2基因，蛋白质印迹法(Western blot)检测EZH2沉默后RPMI8226细胞中EZH2的表达水平，RT-qPCR法检测EZH2的mRNA表达水平，确定基因沉默的效果。EZH2沉默组分别设置对照组(Control)、siRNA阴性对照组(siRNA-NC)和EZH2 siRNA组(siRNA-EZH2)。四甲基偶氮唑盐微量酶反应比色法(MTT法)检测细胞活力，流式细胞术检测细胞周期的改变及凋亡水平，Transwell小室法检测细胞侵袭能力，蛋白质印迹法(Western blot)检测凋亡抑制蛋白(Survivin)、半胱氨酰天冬氨酸特异性蛋白酶-3/7(Caspase-3/7)、基质金属蛋白酶-2/9(MMP-2/9)的表达水平。组间比较采用单因素方差分析(One-way ANOVA)，并用Bonferoni校正的n t检验进行组间两两比较。n 结果:3株人多发性骨髓瘤细胞中EZH2的表达水平显著高于正常人骨髓细胞(分别为0.38±0.08、0.25±0.05、0.22±0.06和0.12±0.03)，而多发性骨髓瘤患者骨髓单个核细胞中EZH2的水平也显著高于正常人骨髓细胞的水平(4.25±0.85比0.15±0.05)。在EZH2沉默的实验中发现siRNA-EZH2组的细胞活力显著低于Control组细胞(0.02±0.01比0.41±0.01)。siRNA-EZH2组细胞S期的比例为(10.22±3.21)%，显著低于Control组细胞[(52.31±3.33)%，n t＝16.310，n P<0.01]，差异有统计学意义。siRNA-EZH2组细胞存活率为(49.15±2.11)%，显著低于Control组细胞[(98.22±1.22)%]。siRNA-EZH2组细胞侵袭能力相比Control组显著降低(106.78±5.62比358.63±7.90)，且siRNA-EZH2组细胞中Survivin、MMP-2/9的蛋白水平显著低于Control组(分别为0.86±0.12比2.15±0.15、3.61±0.07比1.06±0.02和2.24±0.11比0.47±0.08)，Caspase-3/Caspase-7的水平显著高于Control组(分别为2.98±0.03比0.67±0.04和1.96±0.24比0.42±0.02)。n 结论:EZH2在人多发性骨髓瘤中高表达，其作用与增强人多发性骨髓瘤细胞生长、抗凋亡、促侵袭有关。“,”Objective:To study the effect and molecular mechanism of Zeste gene enhancer homologue 2 (EZH2) in human multiple myeloma cell line RPMI8226.Methods:The expression levels of EZH2 in 3 multiple myeloma cell lines and bone marrow mononuclear cells from 20 patients with multiple myeloma were detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). The small interference RNA (siRNA) was used to silence the EZH2 gene expression of RPMI8226 cells. The protein expression of EZH2 at mRNA and protein levels in RPMI8226 cells after EZH2 silencing was detected by RT-qPCR and Western blotting for evaluating the the effect of gene silencing. The cells were set up as control group, siRNA negative control group (siRNA-NC) and EZH2 siRNA group (siRNA-EZH2). The cell viability was measured by 3-(45)-dimethylthiahiazo (-z-y1)-35-di-phenytetrazoliumromide (MTT) assay, the apoptosis and cell cycle were analyzed by flow cytometry, and the cell invasion ability was detected by Transwell assay. The apoptosis inhibitor protein (Survivin), cysteinyl aspartate-specific protease (Caspase)-3/Caspase-7 (Caspase-3/7), matrix metalloproteinase (MMP)-2/MMP-9 were detected by Western blotting.Results:The expression level of EZH2 in three human multiple myeloma cell lines was significantly higher than that in normal human bone marrow cells (0.38±0.08, 0.25±0.05, 0.22±0.06 and 0.12±0.03, respectively), while the level of EZH2 in bone marrow mononuclear cells of multiple myeloma patients was also significantly higher than that of normal human bone marrow cells (4.25±0.85 vs. 0.15±0.05). In the experiment of EZH2 silencing, the cell viability in siRNA-EZH2 group was significantly lower than that in control group. The proportion of synthesis phase (S phase) in siRNA-EZH2 group was (10.22±3.21)%, which was significantly lower than that in control group [(52.31±3.33)%]. The cell viability in siRNA-EZH2 group was (49.15±2.11)%, which was significantly lower than that in control group [(98.22±1.22)%]. The invasion ability in siRNA-EZH2 group was significantly lower than that in control group (106.78±5.62 vs. 358.63±7.90), and the protein levels of Survivin and MMP-2/9 in siRNA-EZH2 group were significantly lower than those in control group (0.86±0.12 vs. 2.15±0.15, 3.61±0.07 vs. 1.06±0.02 and 2.24±0.11 vs. 0.47±0.08), and Caspase-3/Caspase-7 level was significantly higher than that in control group (2.98±0.03 vs. 0.67±0.04 and 1.96±0.24 vs. 0.42±0.02, respectively).Conclusion:EZH2 is highly expressed in human multiple myeloma, and its effect is related to the enhancement of cell growth, anti-apoptosis and invasion ability of multiple myeloma cells.