title: Methylation and expression of Epstein-Barr virus latent membrane protein 1, 2A and 2B in EBV-associated gastric carcinomas and cell lines.
abstract: BACKGROUND
  Promoter CpG methylation of Epstein-Barr virus (EBV) genome plays an essential role in maintaining viral latency. Latent membrane protein (LMP) 1, 2A and 2B of EBV exert multiple oncogenic properties by activating multiple signal pathways and modulating the expression of various oncogenes.
  
  
  OBJECTIVE
  To study the methylation and expression of LMP1, 2A and LMP2B in EBV-positive cell lines and EBV-associated tumors.
  
  
  METHODS
  The methylation profiles of LMP1p, LMP2Ap and LMP2Bp were evaluated by methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP), as well as their expression by quantitative real-time (qRT)-PCR in 41 EBV-associated carcinomas (EBVaGCs) and 5 EBV-positive cell lines.
  
  
  RESULTS
  All LMP promoters were methylated at different degrees in EBV-positive cell lines and hypermethylated in EBV-associated gastric carcinomas, while unmethylated LMP2Ap alleles were detected in B95-8 cell line. Following 5-aza-2'-deoxycytidine (5-aza) treatment, the LMP1 expression was restored along with concomitant promoter demethylation; changes of LMP2A and LMP2B expression were different in different cells.
  
  
  CONCLUSIONS
  Methylation of LMP1, 2A and 2B promoters mediates the silencing of LMP1, 2A and 2B in EBV-associated carcinomas and cell lines in varying degrees, and could be reactivated by demethylation agent and thus may contribute to the therapy of EBVaGCs.
authors.affiliation: Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China; Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Central Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Mengyang
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Central Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Che
authors.affiliation: Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China. Electronic address: qdluobing@163.com.
authors.forename: Bing
authors.initials: B
authors.lastname: Luo
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D000077209:Decitabine; D020031:Epstein-Barr Virus Infections / Q000150:complications*; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D004854:Herpesvirus 4, Human / Q000502:physiology*; D006801:Humans; D011401:Promoter Regions, Genetic; D013274:Stomach Neoplasms / Q000235:genetics* / Q000821:virology; D014763:Viral Matrix Proteins / Q000235:genetics*; D017735:Virus Latency
chemical_list: C037662:EBV-associated membrane antigen, Epstein-Barr virus; D014763:Viral Matrix Proteins; D000077209:Decitabine; D001374:Azacitidine
keywords: EBVaGC; Epigenetics; LMP; Promoter methylation