p21调控胃癌POLD1基因的初步机制探究

Expression regulation of POLD1 gene in gastric carcinoma by p21

目的分析p21调控胃癌POLD1基因表达的初步机制,以探索基于降低胃癌POLD1基因表达并阻断癌细胞恶性增殖的分子靶点。方法利用生物信息学软件Cytoscape、String分析p21与POLD1基因的相互关系;干扰胃癌细胞中p21基因的表达,采用荧光定量PCR及Western blot法检测POLD1基因及细胞周期调控因子CDK2、CDK4、p53、PCNA的表达变化,采用免疫共沉淀实验分析p21与POLD1基因编码的蛋白p125之间的相互作用。结果生物信息学分析发现,p21通过CDK2、PCNA与POLD1直接关联,并与CDK4等细胞周期因子间接相关。干扰胃癌细胞中p21的表达后,POLD1、CDK2、CDK4表达上调,而p53表达下调。免疫共沉淀实验未检测到p21与p125直接相互作用。结论p21能负调控胃癌中POLD1基因的表达,这种调控作用与细胞周期调控因子CDK2、CDK4、p53、PCNA等密切相关。

Purpose To investigate the regulation mechanism of POLD1 gene by p21,and to explore a molecular target which can reduce the expression of POLD1 gene and block the malignant proliferation of carcinoma cells.Methods The relationship between p21 and POLD1 was analyzed by bioinformatics software cytoscape and string,and the expression of p21 gene in gastric carcinoma cells was interfered,then the expression of POLD1 gene and cell cycle regulators such as CDK2,CDK4,p53 and PCNA were detected by fluorescence quantitative PCR and Western blot.The protein interaction between p21 and protein p125 which encoded by POLD1 gene was analyzed by co-immuno-precipitation assay.Results Bioinformatics analysis showed that p21 was directly associated with POLD1 through CDK2 and PCNA,and indirectly associated with CDK4 and other cell cycle regulation factors.After interfering the expression of p21,the expression level of POLD1,CDK2 and CDK4 was up-regulated,while the expression level of p53 was down-regulated.No direct interaction between p21 and p125 was detected by immuno-precipitation assay.Conclusion p21 can negatively regulate the expression of POLD1 gene in gastric carcinoma,which is closely related to CDK2,CDK4,p53 and PCNA.