EZH2对胃癌细胞核因子κB靶基因的调节作用

 目的: 探讨zeste同源物增强子2 (EZH2) 蛋白的表达对胃癌细胞的影响以及可能的作用机制。方法: 用real-time PCR 和Western blot实验检测正常胃黏膜上皮细胞和不同胃癌细胞系中EZH2的mRNA和蛋白表达;采用细胞生长、细胞迁移以及软琼脂增殖实验测定EZH2对胃癌细胞系致癌能力的影响;利用萤光素酶报告基因和real-time PCR检测EZH2对核因子κB靶基因的调节作用;用免疫共沉淀法检测EZH2和p65的相互作用。结果: 与正常胃上皮细胞相比,胃癌细胞系中的EZH2过量表达(P<0.05)。EZH2特异性抑制剂腺苷类似物DZNep处理或shEZH2抑制了AGS和SNU-16细胞系的细胞活力。此外,DZNep和shEZH2 抑制了AGS细胞迁移及软琼脂细胞形成的克隆数目(P<0.05)。shEZH2 下调了核因子κB报告基因或白细胞介素8报告基因的活性以及核因子κB靶基因白细胞介素8、趋化因子配体5及趋化因子配体20的表达(P<0.05)。此外,EZH2可以特异性与p65蛋白相互作用。结论: EZH2 通过调节核因子κB靶基因介导胃癌细胞的生长。

EZH2-mediated regulation of NF-κB target gene expression in gastric cancer

AIM: To explore the mechanism by which over-expression of enhancer of zeste homolog 2 (EZH2) in a panel of gastric cancer cell lines is involved in tumorigenesis of gastric cancer. METHODS: Real-time PCR and Western blot were employed to examine the mRNA and protein levels of EZH2, respectively. MTS assay, cell migration and soft agar assay were performed to investigate the role of EZH2 in the regulation of stomach cancer behaviors. The effect of EZH2 on NF-κB target gene expression was determined by Luciferase reporter and real-time PCR. Co-immunoprecipitation was used to analyze the interaction of EZH2 and p65 in HEK293T cells. RESULTS: The expression levels of EZH2 were significantly increased in the gastric cancer cells compared with normal gastric epithelial cells. Pharmacological inhibition by DZNep or knockdown of EZH2 significantly compromised AGS and SNU-16 cell activity, cell migration and anchorage-independent cell growth. Moreover, siRNA knockdown of EZH2 impaired NF-κB downstream targets, such as IL-8, CXCL5 and CCL20. In addition, the interaction of EZH2 and p65 was detected. CONCLUSION: EZH2 mediates the growth of gastric cancer cells through the regulation of NF-κB downstream gene expression.