IEX-1蛋白在胃癌中的表达及其意义

Expression of IEX-1 protein in gastric carcinoma and its effect on apoptosis and proliferation of human gastric cancer cells

摘要:

目的揭示即刻早期反应X-1（IEX-1）蛋白在胃癌组织及细胞系中的表达，探讨其对人胃癌细胞凋亡和增殖的影响。方法采用免疫组织化学法检测100 例胃镜活检标本中IEX-1 蛋白的表达，用实时荧光定量聚合酶链反应和Western blot 检测人正常胃黏膜细胞GES-1 和胃癌细胞MKN28 中-1 基因和蛋白的表达，同时转染IEX-1 的过表达质粒pcDNA3-FLAG-IEX-1 和干扰质粒pLL3.7-si-IEX-1，分别采用流式细胞术及四甲基偶氮唑盐比色法检测IEX-1 对细胞周期、凋亡及增殖的影响。结果胃癌组织中IEX-1 蛋白表达水平高于正常胃组织和慢性胃炎组织（p <0.05），且随着病情进展，IEX-1 表达水平有逐渐升高的趋势。相对于人正常胃黏膜细胞GES-1，胃癌细胞MKN28 中-1 基因和蛋白表达更高（p <0.05）。与对照组相比，IEX-1 蛋白表达增高后S 期细胞比例升高，G2期细胞比例降低，细胞增殖率升高，凋亡减少（p <0.05），而干扰IEX-1 蛋白表达后，G1期细胞升高，G2期细胞比例下降，细胞增殖率下降，细胞凋亡增加（p <0.05）。结论IEX-1 蛋白在胃癌组织中呈高表达，在人胃癌细胞中上调IEX-1 蛋白能促进细胞增殖，发挥抗凋亡能力，干扰IEX-1 蛋白表达能阻滞细胞周期进程，并诱导凋亡。

Abstract:

Objective To reveal the expression of IEX-1 protein in gastric cancer tissues and cell lines,and investigate the effect of IEX-1 on the proliferation and apoptosis of human gastric cancer cells. Methods Immunohistochemistry was used to detect IEX-1 protein expression in 100 samples of gastric mucosal biopsy.gene and protein expressions were detected by fluorescence qRT-PCR and Western Blot respectively in normal gastric mucosa GES-1 cells and gastric cancer MKN28 cells. pcDNA3-FLAG-IEX-1 plasmid and pLL3.7-si-IEX-1 plasmid were transfected into MKN28 cells respectively, and then cell cycle, apoptosis and proliferation were detected by flow cytometry and MTT assay. Results The expression of IEX-1 protein in the gastric cancer tissues was higher than that in the normal gastric tissues and the chronic gastritis tissues (p <0.05), and the expression level of IEX-1 was gradually increased with the progress of the disease. The expressions of gene and protein in the gastric cancer MKN28 cells were higher than those in the normal gastric mucosal GES-1 cells (p < 0.05). Compared with the control group, the increased expression of IEX-1 protein could increase the proportion of the cells in S phase, decrease the proportion of the cells in G2 phase, increase the rate of cell proliferation, and decrease apoptosis (p < 0.05). After the expression of IEX-1 protein was interfered, the percentage of G1 phase cells increased, that of G2 phase cells decreased,the rate of cell proliferation decreased, apoptosis increased (p < 0.05). Conclusions IEX-1 protein is highly expressed in gastric cancer tissues. Up-regulation of IEX-1 protein expression can promote the proliferation of human gastric cancer cells and play an anti-apoptotic role. Interfering with the expression of IEX-1 protein could block cell cycle progression and induce apoptosis.