中文摘要：

目的 探讨微小核糖核酸（miRNA）-200c及上皮间质转化（EMT）与结肠癌细胞对吉非替尼治疗敏感性的关系.方法 细胞计数试剂盒8（CCK-8）法检测吉非替尼对4种人结肠癌细胞系HT29、SW620、HCT116、SW480的生长抑制作用；以实时定量PCR法检测4种结肠癌细胞中miRNA-200c,上皮标志物（E-钙黏蛋白）,间质标志物[波形蛋白、具锌指E盒结构的同源异性盒1（ZEB 1）]mRNA水平表达,Western印迹检测E-钙黏蛋白、波形蛋白、ZEB 1蛋白水平表达.外源性上调或下调miRNA-200c表达,观察EMT相关基因表达变化及细胞对吉非替尼敏感性的变化.结果 HT29细胞对吉非替尼最为敏感[半数抑制浓度（IC50）=（7.70±0.31） μmol/I],其miRNA-200c与E-钙黏蛋白表达量均为最高,波形蛋白及ZEB 1表达水平极低；HCT116及SW480细胞系对吉非替尼为中度敏感[IC50=（11.88±0.97）,（16.63士0.45）μmol/L],其miRNA-200c、E-钙黏蛋白呈中等程度表达；SW620细胞系对吉非替尼最不敏感[IC50=（26.43±3.68） μmol/L],miRNA-200c与E-钙黏蛋白表达量最低,波形蛋白及ZEB 1表达量均显著高于其他3种细胞系.外源性上调miRNA-200c表达后,SW620细胞中E-钙黏蛋白表达上调,ZEB 1及波形蛋白表达下调,同时细胞对吉非替尼的敏感性亦显著提高；相反,外源性下调miRNA-200c表达后,HT29细胞中E-钙黏蛋白表达下调,ZEB 1及波形蛋白表达上调,同时细胞对吉非替尼的敏感性显著降低.结论 miRNA-200c可能通过调控EMT,上调E-钙黏蛋白表达,进而影响结肠癌细胞对吉非替尼的敏感性.

英文摘要：

Objective To explore the relationship between microRNA （miRNA）-200c expression,epithelial-mesenchymal transition （EMT） and the sensitivity to gefitinib in colon cancer cells.Methods The inhibitory effects of gefitinib on four types of colon cancer cell lines （HT29,SW620,HCT1116,SW480） were examined by cell counting kit-8 （CCK-8） assay.The expressions of miRNA-200c,epithelial marker （E-cadherin） and mesenchymal markers （vimentin and zinc finger Ebox binding homeobox 1 ZEB 1） at mRNA level in four types of colon cancer cell lines were detected by fluorescence quantitative polymerase chain reaction.The expressions of E-cadherin,vimentin and ZEB 1 at protein level were determined by Western blot.After up-or down-regulated the expression of miRNA-200c,the changes of the expression of EMT related genes and the sensitivity to gefitinib were observed.Results HT29 cells were most sensitive to gefitinib （IC50 =（7.70 ± 0.31） μmol/L）,in which the expressions of both miRNA-200c and E-cadherin were the highest,and the expressions of vimentin and ZEB1 were extremely low.HCT116 and SW480 were moderately sensitive to gefitinib （IC50=（11.88±0.97） and （16.63±0.45） μmol/L）,and the expressions of miRNA-200c and Ecadherin were moderate.SW620 cell line was most insensitive to gefitinib （IC50 =（26.43 ± 3.68）μmol/L）,the expressions of miRNA-200c and E-cadherin were the lowest.The expressions of vimentin and ZEB 1 in SW620 were higher than that of the other three types of cell lines.After upregulated the expression of miRNA 200c,the expression of E-cadherin in SW620 cells increased,the expression of ZEB 1 and vimentin decreased,and the sensitivity to gefitinib increased.After downregulated the expression of miRNA-200c,the expression of E-cadherin in HT29 cells decreased,the expression of ZEB 1 and vimentin increased,and the sensitivity to gefitinib decreased.Conclusion miRNA-200c may up-regulate the expression of E-cadherin through EMT regulation,and then influence the sensitivity