Effects Of Cyclooxygenase-2 On Proliferation,Apoptosis And Morphology Of Human Esophageal Squamous Epithelium Cell And Barrett’s Cell And Their Mechanisms

Background and ObjectionBarrett’s esophagus(BE)is characterized by the replacement of normal squamous epithelium by intestinal-type epithelium in the lower esophagus.BE was identified as the precancerous lesion of EAC by the evolution of intestinal metaplasia,dysplasia and esophageal adenocarcinoma(EAC)tissues.The incidence of BE in China is increasing year by year,but its pathogenesis is not clear,and there are no specific drugs for BE.Studies have shown that the high expression of cyclocxygenase-2(COX-2)in BE and EAC tissues is closely related to the clinicopathological typing and atypia of BE,suggesting that COX-2 may BE involved in the occurrence and development of BE and EAC.At present,there are no studies on the effect of COX-2 expression on BE at the cellular and molecular levels and the role of COX-2 in the occurrence and development of BE.Investigating the role and molecular mechanism of COX-2 in BE cell genesis and atypical transformation by studying the effects of cyclooxygenase-2 on proliferation,apoptosis and morphology of human esophageal squamous epithelium cell and Barrett cell lines and their molecular mechanisms.Methods1.Human esophageal squamous epithelium cell(HET-1A)and Barrett cell(BAR-T)lines were transfected with COX-2 expression vector and COX-2 siRNA.Cell proliferation and apoptosis were detected before transfection and 4 8 hours after transfection.The expression of COX-2,NF-κB,MUC-2,CDX-2 and BMP-4 before and after transfection was demonstrated by Western blot.The morphology and microstructure of cells were observed by electron microscope.2.HET-1A and BAR-T cell lines were pretreated with acid,bile salt and their mixture.COX-2 siRNA vector was instantaneously transfected after different time of stimulus intervention,and cell proliferation and apoptosis were detected 48 hours later.The expression of COX-2,NF-κB,MUC-2,CDX-2 and BMP-4 were demonstrated by Western blot.The morphology and microstructure of cells were observed by electron microscope.ResultsThe cells viability of the COX-2 overexpression was significantly higher than that of control group,while the cells viability of COX-2 siRNA treatment was significantly lower than that of control group.The intestinal metaplasia and atypia were observed in cells over expressing COX-2.Acid,bile salts,and their mixture inhibited the viability of the two cell lines,but the inhibitory effect of the mixture was stronger than single treatment with either.COX-2 siRNA strengthened the anti-proliferative effects of the mixture on Het-1A and BAR-T cells.Apoptosis was induced by acid,bile salts and their mixtures,with the strongest effect of acid and bile salts mixtures.Apoptosis was increased after gene silencing COX-2.Expression of NF-κB,CDX-2 and BMP-4 was positively correlated with COX-2 expression.ConclusionCOX-2 may influence the viability,atypia and intestinal metaplasia of human esophageal squamous epithelium cells and Barrett cells.Activation of NF-κB,CDX-2,and BMP-4 signaling pathway by COX-2 may be part of the mechanisms.