Study Of Methylation Status And Expressionon On LOXL1Gene In Epstein-Barr Virus-associated Gastric Carcinoma Tiusses And Gastric Carcinoma Cell Lines

Epstein-Barr virus (EBV) is known as an important DNA tumor virus. EBV infection is related to gastric carcinoma, but pathogenic mechanism of that is not well understood. Methylation of tumor suppressor gene induced by EBV infection is known as an important mechanism for the scilence of tumor suppressor gene.Objective The study aimed to explore the influence of EBV infection on LOXL1gene promoter methylation status and transcriptional expression, and further to research the roles of LOXL1played in the occurrence of EBV associated carcinoma.Methods The methylation staus of LOXL1gene promoter in EBV-positive and-negative gastric cancer cell lines and EBVaGCs and EBVnGCs tissue was detected by methylation-specific PCR and bisulfite genomic sequencing.. The demethylation levels of LOXL1gene promoters was detected by bisulfite genomic sequencing and MSP, and LOXL1gene expression was detected by the real-time quantitative PCR before and after treatment with5-Aza-CdR in EBV positive cell lines GT38and Raji.Results①MSP result showed the methylation staus of LOXL1gene promoter was all M+U type in EBV-positive and-negative gastric carcinoma cell lines.②There were20sites of CpG islands in LOXL1gene promoter. BGS results showed that most of CpG sites on LOXL1gene promoter were methylation in EBV positive gastric carcinoma cell lines, and no methylation in EBV negative gastric carcinoma cell lines.③MSP results showed that methylation staus of LOXL1gene promoter was M+U type in EBVaGCs and EBVnGCs. Methylation status of LOXL1gene in EBVaGC tissue was significantly higher evident than EBVnGC.④BGS results showed that different gastric carcinoma specimens represented different methylation staus. Average degree of LOXL1gene promoter methylation in EBVaGC was significantly higher than EBVnGCs.⑤After treated with5-Aza-CdR, the LOXL1gene promoter methylation in EBV positive gastric carcinoma cell lines was lower than efore.⑥LOXL1gene expression was different between EBV-negative and EBV-positive gastric carcinoma cell lines, its expression in EBV negative gastric carcinoma cell lines is4.35times higher than in EBV positive gastric carcinoma cell lines; and after treated by5-Aza-CdR, LOXL1gene expression is 2.33times higher than before.Conclusion Our date indicate that there is aberrant hypermethylation of LOXL1gene promoter in gastric carcinoma. EBV infection may further induce LOXL1gene methylation and down-regulate its expression, and this may be involved in EBV associated carcinoma occurrence.