title: Suberoylanilide hydroxamic acid induces viral lytic cycle in Epstein-Barr virus-positive epithelial malignancies and mediates enhanced cell death.
abstract: In Epstein-Barr virus (EBV)-associated malignancies, the virus is harbored in every tumor cell and persists in tightly latent forms expressing a very limited number of viral latent proteins. Induction of EBV lytic cycle leads to expression of a much larger number of viral proteins, which may serve as potential therapeutic targets. We found that 4 histone deacetylase inhibitors, trichostatin A (TSA), sodium butyrate (SB), valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA), all significantly induced EBV lytic cycle in EBV-positive gastric carcinoma cells (AGS/BX1, latency II) but only weakly induced in Burkitt lymphoma cells (AK2003, latency I) and did not induce in lymphoblastoid cells (LCLs, latency III). Interestingly, SAHA potently induced viral lytic cycle in AGS/BX1 cells at micromolar concentrations (evidenced by 8-fold increase in viral DNA replication, strong expression of viral lytic proteins and production of infectious virus particles) and mediated enhanced cell death of EBV-positive AGS/BX1 cells when compared with that of EBV-negative AGS cells, possibly related to cell cycle arrest at G2/M phase. Furthermore, SAHA effected strong induction of EBV lytic cycle in nasopharyngeal carcinoma but not in NK lymphoma cells (both expressing EBV latency II pattern), indicating preferential viral lytic induction in epithelial rather than lymphoid malignancies. In conclusion, SAHA is found to be a potent EBV lytic cycle inducing agent, which warrants further investigation into its potential application as a novel virus-targeted drug for treatment of EBV-associated epithelial malignancies.
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong SAR, China.
authors.forename: K F
authors.initials: KF
authors.lastname: Hui
authors.forename: Alan K S
authors.initials: AK
authors.lastname: Chiang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002051:Burkitt Lymphoma / Q000188:drug therapy / Q000821:virology; D002087:Butyrates / Q000494:pharmacology; D002277:Carcinoma / Q000188:drug therapy* / Q000821:virology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D004854:Herpesvirus 4, Human / Q000187:drug effects*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D007938:Leukemia / Q000188:drug therapy / Q000821:virology; D016133:Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000821:virology; D014635:Valproic Acid / Q000494:pharmacology; D000077337:Vorinostat
chemical_list: D000970:Antineoplastic Agents; D002087:Butyrates; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; C012589:trichostatin A; D000077337:Vorinostat; D014635:Valproic Acid