胰岛素样生长因子结合蛋白7基因在胃癌细胞中的表达及甲基化调控

目的 研究胰岛素样生长因子结合蛋白7(IGFBP7)mRNA在胃癌细胞中的表达及其甲基化调控.方法 分别培养胃癌细胞株高分化MKN-28、中分化SGC-7901和AGS、低分化MKN- 45以及胃黏膜正常上皮细胞(GES-1).提取细胞RNA,采用RT-PCR法检测IGFBP7 mRNA在各细胞株中的表达.提取细胞基因组DNA,甲基化修饰后采用甲基特异性PCR(MSP)分析其CpG岛甲基化状态.采用不同浓度去甲基化药物5'-杂氮-2'-脱氧胞嘧啶(5-aza-dc)处理细胞株后,经Real-time PCR定量药物处理前后各细胞株IGFBP7 mRNA的相对表达量.结果 各肿瘤细胞株中IGFBP7 mRNA表达较GES-1降低或消失.MSP检测IGFBP7 mRNA表达降低和消失的细胞株均有CpG岛不同程度的甲基化.不同浓度5-aza-dc处理细胞后,IGFBP7 mRNA的表达量呈剂量依赖性增高.结论 IGFBP7 mRNA在胃癌细胞株中低表达或不表达,其表达下调与其CpG岛甲基化有关.5-aza-dc可使IGFBP7 mRNA表达降低的胃癌细胞株重新表达IGFBP7 mRNA,提示IGFBP7基因CpG岛甲基化可能是IGFBP7在胃癌细胞系中表达缺失的分子机制.

Expressions of insulin-like growth factor binding protein 7 in human gastric cancer cell lines and methylation regulation

Objective To investigate the insulin-like growth factor binding protein 7(IGFBP7)gene expressions in gastric cancer cell lines and methylation regulation.Methods Four gastric cancer cell lines,high-differentiated MKN-28,middle-differentiated SGC-7901 and AGS,poorly differentiated MKN-45,and normal gastric epithelial cell line(GES-1)were cultured.The IGFBP7 mRNA expressions in different cell lines were detected by RT-PCR.The DNA methylation status was assayed by methylation-specific PCR(MSP).Gastric cancer c...