中文摘要：

目的探讨在脱氧胆酸（deoxycholic acid,DCA）诱导Barrett食管（Barrett’s esophagus,BE）形成中,Krüppel样锌指转录因子4（Krüppel-like factor 4,KLF4）与同源异型框转录因子2（caudalrelated homeodomain transcription factor 2,CDX2）的作用。方法采用免疫组化S-P法检测49例人正常食管组织和22例BE组织中KLF4、CDX2的表达;体外培养Het-1A细胞,依据DCA处理时间分为0 h组（未经DCA处理）、4 h组、8 h组、12 h组并进行DCA处理。分别设置空白对照组、阴性siRNA对照组、阴性siRNA＋DCA处理12 h组、KLF4-siRNA干扰组、KLF4-siRNA干扰＋DCA处理12 h组,进行相应处理。设置空白对照组、阴性病毒对照组、阴性病毒＋DCA处理12 h组、KLF4过表达病毒组,进行相应处理。待上述各实验组处理结束后,运用Real-time PCR、Western blot检测各组KLF4、CDX2、MUC2mRNA及蛋白的表达。结果免疫组化检测发现：在22例BE组织中,KLF4阳性表达15例,阳性率68.18%,阳性染色主要集中在细胞核;CDX2阳性表达16例,阳性率72.73%,阳性染色也主要集中在细胞核。与人正常食管鳞状上皮组织比较,BE组织中KLF4、CDX2表达均增高（χ2=18.642,P〈0.05;χ2=23.678,P〈0.05）。Real-time PCR及Western blot检测结果显示：随DCA处理时间的增加,Het-1A细胞KLF4、CDX2、MUC2的表达逐渐升高（P〈0.05）;KLF4-siRNA干扰组及KLF4-siRNA干扰＋DCA处理12 h组中,KLF4、CDX2、MUC2表达均下调,且不再随DCA处理的刺激而升高（P〈0.05）;此外,阴性病毒＋DCA处理12 h组及KLF4过表达病毒组中,KLF4、CDX2、MUC2表达均上调,且KLF4过表达病毒组3个基因蛋白表达上调更为显著（P〈0.05）。结论 DCA通过KLF4上调CDX2,间接引起BE标志性分子MUC2的表达上调,从而促进正常食管上皮向BE转化。

英文摘要：

Objective To investigate the roles of Krüppel-like factor 4（ KLF4） and caudal-related homeodomain transcription factor 2（ CDX2） in the development of Barrett ’s esophagus（ BE） induced by deoxycholic acid（ DCA）. Methods Immunohistochemical SP staining was applied to evaluate the expression levels of KLF4 nd CDX2 in 49 samples of normal esophageal tissues and 22 samples of BE tissues. Human esophagus epithelial cell line Het-1A was treated with DCA for 0,4,8 and 12 h. The siRNA of KLF4 was designed and transfected into Het-l A cells. The Het-l A cells were assigned into blank group,negative controlsiRNA group,negative control-siRNA ＋ DCA treatment group,KLF4-siRNA group,and KLF4-siRNA ＋ DCA treatment group. The Het-1A cells with KLF4 over-expression were also established by transfection of overexpression recombinant lentivirus into the cells. Then,the expression levels of KLF4,CDX2 and MUC2 at mRNA and protein levels were detected by real-time PCR and Western blot assay,respectively. Results Among the 22 patients with BE,immunohistochemical staining indicated that 15 cases had positive expression of KLF4（ 68. 18%）,which mainly located in the nucleus,and 16 cases had positive expression of CDX2（ 72. 73%）,mainly located in the nucleus too. KLF4 and CDX2 was strongly expressed in the BE tissues,and its level was significantly higher in the BE compared with normal esophageal tissues（ Chi square =18. 642,P 〈 0. 05; Chi square = 23. 678,P 〈 0. 05）. Real-time PCR and Western blot assay revealed that the mRNA and protein levels of KLF4,CDX2 and MUC2 were enhanced in a time-dependent manner in Het-l A cells induced by DCA（ P 〈 0. 05）,their levels were significantly suppressed in KLF4-siRNA groups,and could not be enhanced by stimulation of DCA again,but the levels were significantly increased in KLF4-overexpression group. Conclusion DCA up-regulates the expression of CDX2 by KLF4,which cause higher expression of MUC2 and thus promote the transformation of normal esophageal epithe