Synthesis and antiviral effects of isosteviol-derived analogues against the hepatitis B virus.
Among several isosteviol-derived analogues, NC-8 (ent-16-oxobeyeran-19-N-methylureido) showed inhibitory potency against the hepatitis B virus (HBV) in HepG2 2.2.15 cells. Its anti-HBV mechanism was then next investigated in a human hepatoma cell culture system. Results showed that it specifically inhibited viral gene expression and reduced the level of encapsidated viral DNA intermediates in Huh7 cells that expressed replicating HBV. It also potently attenuated all viral promoter activity in HBV-expressing Huh7 cells, but not in cells lacking HBV expression. By examining its antiviral mechanism in cellular signaling pathways, NC-8 was found to inhibit the activity of the nuclear factor (NF)-κB element-containing promoter, but only slightly enhanced activities of activator protein (AP)-1- and interferon-sensitive response element (ISRE)-containing promoters in HBV-expressing cells. NC-8 also significantly eliminated NF-κB (p65/p50) and Toll-like receptor (TLR)2 proteins, but increased the IκBα protein level in a dose-dependent manner in HBV-transfected Huh7 cells, while these protein levels were apparently unchanged in non-transfected cells. Meanwhile, NC-8-treated nuclear extracts that co-expressed HBV inhibited the binding of NF-κB to the CS1 site of HBV major surface gene and specifically attenuated CS1-containing promoter activity. Taken together, this study suggests that the antiviral mechanism of NC-8 appears to be mediated by disturbing replication and gene expression of HBV and by inhibiting the host TLR2/NF-κB signaling pathway.
Department of Biological Science and Technology and Research Center for Biodiversity, China Medical University, Taichung 404, Taiwan.
Tsurng-Juhn
TJ
Huang
Department of Biological Science and Technology and Research Center for Biodiversity, China Medical University, Taichung 404, Taiwan; Department of Pharmaceutical Sciences, School of Pharmacy, Taipei Medical University, Taipei 110, Taiwan; Long Shine Biopharma Co., Tainan 722, Taiwan.
Bo-Hon
BH
Chou
Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
Cheng-Wen
CW
Lin
Department of Biological Science and Technology and Research Center for Biodiversity, China Medical University, Taichung 404, Taiwan.
Jen-Hsien
JH
Weng
Department of Biological Science and Technology and Research Center for Biodiversity, China Medical University, Taichung 404, Taiwan.
Chang-Hung
CH
Chou
Department of Pharmaceutical Sciences, School of Pharmacy, Taipei Medical University, Taipei 110, Taiwan; Division of Chinese Medicinal Chemistry, National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei 112, Taiwan.
Li-Ming
LM
Yang
Department of Pharmaceutical Sciences, School of Pharmacy, Taipei Medical University, Taipei 110, Taiwan. Electronic address: shwu-lin@tmu.edu.tw.
Shwu-Jiuan
SJ
Lin
D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002470:Cell Survival; D002478:Cells, Cultured; D045786:Diterpenes, Kaurane / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006515:Hepatitis B virus / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D000998:Antiviral Agents; D045786:Diterpenes, Kaurane; C515747:isosteviol
Hepatitis B virus; Human hepatoma cells; Isosteviol derivative; NF-κB; TLR2