The Role And Mechanism Of HNF4? On CDX2 In Bile Acid Induced Gastric Intestinal Metaplasia

Background: Gastric intestinal metaplasia is closely related to gastric cancer.During the development of gastric cancer,gastric intestinal metaplasia is the most important stage of gastric cancer,and is also the most important precancerous lesion.The occurrence of gastric intestinal metaplasia can promote to occurrence and development of gastric cancer.Therefore,theresearch on the intestinal metaplasia of gastric mucosa has become a focus in the research ofgastric cancer.Caudal-related homeobox 2(CDX2)is a tailed homologous gene involved inthe regulation of intestinal epithelial cell proliferation and differentiation.Ectopic expressionof CDX2 can induce intestinal phenotype,it is related to a variety of tissues and organs intestinal metaplasia.Hepatocyte nuclear factor(HNF)4? is a nuclear receptor.Abnormalexpression of HNF4? can cause a variety of pathological processes,and has closely linkedwith many malignant tumors.At present,it has been reported that HNF4? is associated withthe differentiation and proliferation of intestinal epithelial cells and induces the non-intestinalepithelial cells transform to intestinal epithelium phenotypes,It indicates that HNF4? is alsoinvolved in intestinal metaplasia.We will preliminarily study and research the expressionlevel,the molecular function,the role and mechanism of HNF4? and CDX2 in gastricepithelial cell lines were based on the previous experiments.Objective: To investigate the effect of HNF4? on CDX2 in bile acid-mediated gastric mucosa intestinal metaplasia and to study its regulatory mechanism.Methods:1.Immunohistochemistry was used to verify the expression of HNF4? and CDX2 in gastric intestinal metaplasia.2.Stimulation GES-1 cell with chenodeoxycholic acid(CDCA)construct model of intestinal metaplasia cell,using q RT-PCR and western blot to verify HNF4? and CDX2 expression and screen appropriate concentration of CDCA.3.Over expression and inhibition of HNF4? lentivirus vectors were constructed,and overexpression lentivirus and lentiviral negative control were transfected into GES-1 and SGC7901 cells,the inhibition of HNF4? and its negative control were transfected into BGC823 and AGS cells.The expression of HNF4? was verified by q RT-PCR and western blot.4.Verification the impact of HNF4? on CDCA stimulation GES-1 cell transfected with si-HNF4? and over expression and down-regulation HNF4? lentiviral vector cell lines.5.The reporter gene experiment was used to verify HNF4? regulate CDX2.Result: 1.Immunohistochemical staining suggested that the positive expression of HNF4? and CDX2 in gastric intestinal metaplasia were significantly higher than that of gastritis.2.Compared with GES-1,the expression of HNF4? and CDX2 were significantly increased in the gastric intestinal metaplasia cell model induced by CDCA.3.Successfully constructed a stably transfected cell lines with overexpression and inhibition of HNF4?.4.Functional test results demonstrated that in the gastric intestinal metaplasia cell model established by CDCA,after interfering with the expression of HNF4?,the expression of CDX2,VILLIN and TFF3 were decreased.In the stably transfected cell lines,over expression of HNF4? led to increased expression of CDX2,VILLIN and TFF3.In contrast,inhibition of HNF4? resulted in decreased expression of CDX2,VILLIN and TFF3.5.Mechanism study: Reporter gene experiments suggest that HNF4? can regulate CDX2.Conclusion: HNF4? participates in the bile acid mediated gastric intestinal metaplasia by up-regulation CDX2 directly.