title: Maintenance of the viral episome is essential for the cell survival of an Epstein-Barr virus positive gastric carcinoma cell line.
abstract: While Epstein Barr virus (EBV) is associated with about 10% of gastric carcinomas worldwide, the role of the virus in the tumorigenesis of EBV-associated gastric carcinoma (EBVaGC) is unclear. Previously, we reported that a gastric cancer cell line, SNU-719, that is naturally infected with EBV closely resembles EBVaGC. Here, we attempted to eliminate the EBV genome from SNU-719 cells to ascertain the influence of EBV in EBVaGC. Southern blotting and fluorescence in situ hybridization (FISH) showed that EBV genomes were maintained as episomes in SNU-719 cells. To remove EBV episomes, SNU-719 cells were first cultured in a hydroxyurea (HU)-containing medium for up to 6 months. Real-time polymerase chain reaction and FISH results revealed no evidence of HU-mediated EBV genome reduction, although cell growth was reduced by acute HU treatment in dose- and time-dependent manners. Two small interfering RNAs against Epstein Barr nuclear antigen 1 (EBNA1) abrogated over 90% of the ectopic EBNA1 expression in HeLa cells, but only 40% of endogenous EBNA1 expression in SNU-719 cells. Together, our data suggest that maintenance of latent EBV infection is essential for the viability of EBVaGC cells, avoiding elimination of EBV episomes from the cells.
authors.affiliation: Department of Biomedical Sciences, Catholic University of Korea, Seoul, 137-701, Korea.
authors.forename: Sang Taek
authors.initials: ST
authors.lastname: Oh
authors.forename: Myungshin
authors.initials: M
authors.lastname: Kim
authors.forename: Suk Kyeong
authors.initials: SK
authors.lastname: Lee
mesh_terms: D015139:Blotting, Southern; D002277:Carcinoma / Q000473:pathology / Q000821:virology*; D049109:Cell Proliferation; D002470:Cell Survival; D002472:Cell Transformation, Viral / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics*; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006367:HeLa Cells; D004854:Herpesvirus 4, Human / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D017404:In Situ Hybridization, Fluorescence; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010957:Plasmids / Q000187:drug effects; D016133:Polymerase Chain Reaction; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D013274:Stomach Neoplasms / Q000473:pathology / Q000821:virology*; D013997:Time Factors; D014162:Transfection
chemical_list: D019309:Epstein-Barr Virus Nuclear Antigens; D019384:Nucleic Acid Synthesis Inhibitors; D034741:RNA, Small Interfering; C417029:EBV-encoded nuclear antigen 1; D006918:Hydroxyurea