Promoter Region Methylation Status Of JAM3 Gene And The Expression Regulation Of JAM3 In Human Esophageal Cancer

BackgroundEsophageal cancer is one of the most common malignant tumors,ranking seventh in morbidity and sixth in mortality globally.The incidence of esophageal cancer is varied considerably in different location.In China,the areas surrounding the Taihang Mountains exhibit the highest incidence,and esophageal squamous cell carcinoma(ESCC)is the predominant pathological type.Environmental factors,combined with genetic and epigenetic events,play important roles in esophageal cancer development.Junctional adhesion molecule-3(JAM3)is a member of the JAM family,also known as the Junctional adhesion molecule-c(JAMC).Recently,it was reported that JAM3 was frequently methyled in coloretal cancer,and JAM3 was a tumor suppressor in colorectal cancer.The promoter region methylation status of JAM3 gene in human esophageal Cancer remain unclear.AimOur study is to explore the promoter region methylation status of JAM3 gene and the expression regulation of JAM3 in human esophageal cancer,and to demostrate the possibility of abnormal methylation of JAM3 gene as a potential diagnostic marker for esophageal squamous cell cancer.Methods1.Semi-quantitative RT-PCR was used to detect the expression of JAM3 gene in esophageal cancer cell lines KYSE140,KYSE150,KYSE410,KYSE450,COLO680 N,KYSE520 and TE13 before and after 5-Aza-2’-deoxycytidine(5-Aza-dc)treatment.2.The methylation status of the JAM3 gene in esophageal cancer cell lines was detected by methylation-specific PCR(MSP).3.The methylation status of the JAM3 gene in normal esophageal mucosa tissues was detected by MSP,and it was used to rule out the tissue specific methylation of JAM3.4.The methylation status of the JAM3 gene in 83 esophageal squamous cell cancer tissues was detected by MSP.5.Statistical method:SPSS22 software was used to analyze the relationship between JAM3 methylation and clinical data,count data was presented by rate.And Chi-square test was emplyed in our study,P < 0.05 was considered to be significant difference.Results1.The mRNA level of JAM3 was highly expressed in KYSE520,KYSE140 and KYSE450 cells,while was lost in KYSE410,COLO680 N,TE13 and KYSE150 cells.The expression of JAM3 was induced after 5-Aza-dc treatment in KYSE410,COLO680 N,TE13 and KYSE150 cells.2.The promoter region of JAM3 was unmethylated in KYSE520,KYSE140 and KYSE450 cells,while was completely methylated in KYSE150,KYSE410,TE13 and COLO680 N cells.3.The promoter region of JAM3 was unmethylated in normal esophageal mucosa,and the tissue specificity of JAM3 methylation was ruled out.4.The methylation of JAM3 was found in 50.6%(42/83)of esophageal squamous cell carcinoma samples.Methylation of JAM3 was significantly associated with tumor location(P<0.05),where the upper thoracic segment had the highest methylation rate(61.90%),the lower thoracic segment had the lowest(26.32%).ConclusionThe expression of JAM3 in esophageal cancer is regulated by promoter region methylation.JAM3 is frequently methylated in human esophageal squamous cell carcinoma tissues,and methylation of JAM3 is a potential diagnostic marker in human esophageal squamous cell carcinoma tissues.