title: Epigallocatechin gallate inhibits HBV DNA synthesis in a viral replication - inducible cell line.
abstract: OBJECTIVE
  To analyze the antiviral mechanism of Epigallocatechin gallate (EGCG) against hepatitis B virus (HBV) replication.
  
  
  METHODS
  In this research, the HBV-replicating cell line HepG2.117 was used to investigate the antiviral mechanism of EGCG. Cytotoxicity of EGCG was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hepatitis B virus e antigen (HBeAg) and hepatitis B virus surface antigen (HBsAg) in the supernatant were detected by enzyme-linked immunosorbent assay. Precore mRNA and pregenomic RNA (pgRNA) levels were determined by semi-quantitative reverse transcription polymerase chain reaction (PCR) assay. The effect of EGCG on HBV core promoter activity was measured by dual luciferase reporter assay. HBV covalently closed circular DNA and replicative intermediates of DNA were quantified by real-time PCR assay.
  
  
  RESULTS
  When HepG2.117 cells were grown in the presence of EGCG, the expression of HBeAg was suppressed, however, the expression of HBsAg was not affected. HBV precore mRNA level was also down-regulated by EGCG, while the transcription of precore mRNA was not impaired. The synthesis of both HBV covalently closed circular DNA and replicative intermediates of DNA were reduced by EGCG treatment to a similar extent, however, HBV pgRNA transcripted from chromosome-integrated HBV genome was not affected by EGCG treatment, indicating that EGCG targets only replicative intermediates of DNA synthesis.
  
  
  CONCLUSIONS
  In HepG2.117 cells, EGCG inhibits HBV replication by impairing HBV replicative intermediates of DNA synthesis and such inhibition results in reduced production of HBV covalently closed circular DNA.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academic of Sciences, Wuhan 430071, Hubei Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Li-Xia
authors.initials: LX
authors.lastname: Li
authors.forename: Qing-Jiao
authors.initials: QJ
authors.lastname: Liao
authors.forename: Chun-Lan
authors.initials: CL
authors.lastname: Liu
authors.forename: Xu-Lin
authors.initials: XL
authors.lastname: Chen
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004261:DNA Replication / Q000187:drug effects*; D004279:DNA, Viral / Q000096:biosynthesis / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D017930:Genes, Reporter; D056945:Hep G2 Cells; D006514:Hepatitis B Surface Antigens / Q000378:metabolism; D006513:Hepatitis B e Antigens / Q000378:metabolism; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000276:immunology; D006801:Humans; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens; D012333:RNA, Messenger; D012367:RNA, Viral; D002392:Catechin; C045651:epigallocatechin gallate