Egr1信号途径参与NDRG1表达调节的机制研究

The mechanisms of Egr1 signaling pathway involved in the regulation of NDRG1 expression

目的:研究人宫颈癌细胞中早期生长反应基因1(Egr1)信号途径参与N-myc下游调节基因1(NDRG1)表达调节的机制。方法:以人宫颈癌细胞株SiHa为研究对象,利用siRNA干扰技术使Egr1基因沉默,用RT-PCR和W estern blot检测转染前后Egr1表达的变化。通过RT-PCR和W estern blot检测细胞在低氧条件下,以及转染siRNA-Egr1后在低氧或低氧模拟物(DFX)条件下,Egr1与NDRG1表达的变化。结果:siRNA能有效地抑制Egr1基因表达(P<0.001)。低氧条件下,Egr1、NDRG1的蛋白水平均明显升高(P<0.001)。转染siRNA-Egr1 48h后,细胞在低氧条件下作用1h,Egr1 mRNA表达显著下降(P<0.05)。细胞转染siRNA-Egr1 48h后,在低氧及DFX条件下作用24h,结果显示DFX使NDRG1 mRNA的表达显著高于低氧条件(P<0.05)。同时也显示siRNA-Egr1能够使NDRG1 mRNA水平明显减少(P<0.05)。结论:体内环境因素如低氧、DFX等上调NDRG1基因的表达,通过Egr1信号途径参与NDRG1在宫颈癌细胞中表达的调节。

Objective：To investigate the mechanisms of early growth response gene 1 （Egrl） signaling pathway involved in the regulation of N-myc downstream regulated gene 1 （ NDRG1 ） expression in human cervical cancer. Methods ： siRNA-Egrl was transfected into Si- Ha cells to silence Egrl gene,RT-PCR and Western blot were used to examine the expressions of Egrl mRNA and protein,respectively. RT-PCR and Western blot were used to detect the expressions of Egr1 and NDRGI in ceils treated with hypoxia,in transfected or untransfected cells treated with hypoxia or mimicking hypoxia reagent （deferoxamine, DFX）. Results ： siRNA-Egrl specifically suppressed the expressions of Egrl mRNA and protein（ P〈0. 001 ） ,the protein level of Egrl and NDRG1 significantly increased in hypoxia condition （P〈0. 001 ）. Under hypoxia environment,Egrl mRNA remarkably decreased in cells after transfection with siRNA-Egr1 （P〈 0.05 ）. After transfection with siRNA-Egrl 48h, cells were treated with hypoxia or deferoxamine （DFX） for 24h,the level of NDRG1 mRNA was more strongly induced by DFX than hypoxia. Compared with siRNA-N,the level of NDRG1 mRNA significantly reduced in cells transfected with siRNA-Egrl （P〈0.05）. Conclusion ： Environment factors in vivo such as hypoxia or mimicking hypoxia reagent （DFX） can induce the expression of NDRG1 gene via Egr1-dependent pathway in human cervical cancer cells.