A novel anti-hepatitis B virus regent iCDM-34 reveals suppression of cccDNA accompanied with aryl hydrocarbon receptor activation

Background & Aims: IFN-alpha and -gamma have been reported to suppress cccDNA via APOBEC3 cytidine deaminase activity, and CDM-3008, an IFNAR2 agonist, also suppress cccDNA through interferon signaling. In order to develop a novel anti-HBV drug for functional or complete cure, we performed in silico screening using a structure of CDM-3008-binding pocket in IFNAR2. Approach & Results: The binding pocket of CDM-3008 in IFNAR2 was determined by LC-MS/MS using a CDM-3008-based molecular probe, CDM-3095 and a recombinant protein of IFNAR2 extracellular region. We conducted in silico screening of the binding compounds fitting the steric structure of the pocket. We identified 37 compounds and named them iCDM-1–37. We found that iCDM-34 showed anti-HCV and anti-HBV activities. We measured the anti-HBV activity of iCDM-34 with or without entecavir (ETV). iCDM-34 suppressed pregenome RNA, covalently closed circular DNA (cccDNA), HBsAg, and HBeAg and clearly exhibited synergistic inhibitory effects with ETV. Metabolic stability of iCDM-34 was measured in human, mouse, and rat microsomal fractions. iCDM-34 was stable in human liver microsomal fraction. Furthermore, anti-HBV activity in human hepatocyte-chimeric mice revealed that iCDM-34 was not effective as a single agent, but when combined with ETV, it suppressed HBV DNA and cccDNA compared to ETV alone. Phosphoproteome analysis showed no activation of IFN signaling with iCDM-34 treatment. Transcriptome analysis of interferon-stimulated genes (ISGs) revealed no increase in the expression, while downstream factors of aryl hydrocarbon receptor (AhR) showed increased expression. Conclusion: iCDM-34 is a novel anti-HBV drug that induces AhR activation and suppresses cccDNA. Conclusion: iCDM-34 is a novel anti-HBV drug that induces AhR activation and suppresses cccDNA. Overall, 12 samples were analyzed. PXB cells cultured in 24-well plates were infected with 3 genome equivalents per cell of HBV C_AT. After 24 days of infection, the cells were treated with DMSO, 0.3 and 30 microM iCDM-34 or 1000 IU/ml IFNalpha for 7 days (n=3).