SUPPRESSIVE EFFECTS OF DESTRUXIN-B ON HEPATITIS-B-VIRUS SURFACE-ANTIGEN GENE-EXPRESSION IN HUMAN HEPATOMA-CELLS

Destruxin B, a cyclodepsipeptide was originally identified as a plant pathogen from the fungus, Alternaria brassicae. We examined the antivi ral activity of destruxin B and found that it suppresses the expressio n of the hepatitis B viral surface antigen (HBsAg) gene in human hepat oma Hep3B cells which carry an integrated viral gene in its chromosome . In contrast, destruxin B shows no cytotoxic effect on the viability of the cells. Furthermore, it can be shown that destruxin B can revers ibly suppress HBsAg production by Hep3B cells in a concentration-depen dent manner with EC50 of 0.5 mu M. Northern blot analysis indicates th at the suppression of HBsAg gene expression by destruxin B is mainly a t the mRNA level. Destruxin B not only suppresses the endogenously exp ressed HBsAg in the Hep3B cells but also suppresses the HBsAg produced either from the stable transfected HBV DNA in another human hepatoma HuH-7 cell line which carry no endogenous HBV genome. These results su ggest that destruxin B may have future potential for development as a specific anti-HBV drug. (C) 1997 Elsevier Science B.V.