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During the hepatitis B virus (HBV) life cycle, nucleocapsid assembly is essential for HBV replication. Both RNA reverse transcription and DNA replication occur within the HBV nucleocapsid. HBV nucleocapsid is consisted of core protein (HBcAg), whose carboxy-terminal domain (CTD) contains an Arg-rich domain (ARD). The ARD of HBcAg does contribute to the encapsidation of pregenomic RNA (pgRNA). Previously, we reported a small-molecule, NZ-4, which dramatically reduced the HBV DNA level in an in vitro cell setting. Here, we explore the possible mechanisms by which NZ-4 inhibits HBV function. As an HBV inhibitor, NZ-4 leads to the formation of genome-free capsids, including a new population of capsid that runs faster on agarose gels. NZ-4's activity was dependent on the presence of the ARD I, containing at least one positively charged amino acid. NZ-4 might provide a new option for further development of HBV therapeutics for the treatment of chronic hepatitis B., (Copyright © 2015. Published by Elsevier B.V.)

Here we first identified a novel pyridazinone derivative, compound 3711, as a nonnucleosidic hepatitis B virus (HBV) inhibitor in a cell model system. 3711 decreased extracellular HBV DNA levels by 50% (50% inhibitory concentration [IC50]) at 1.5 ± 0.2 μM and intracellular DNA levels at 1.9 ± 0.1 μM, which demonstrated antiviral activity at levels far below those associated with toxicity. Both the 3TC/ETV dually resistant L180M/M204I mutant and the adefovir (ADV)-resistant A181T/N236T mutant were as susceptible to 3711 as wild-type HBV. 3711 treatment induced the formation of genome-free capsids, a portion of which migrated faster on 1.8% native agarose gel. The induced genome-free capsids sedimented more slowly in isopycnic CsCl gradient centrifugation without significant morphological changes. 3711 treatment decreased levels of HBV DNA contained in both secreted enveloped virion and naked virus particles in supernatant. 3711 could interfere with capsid formation of the core protein (Cp) assembly domain. A Cp V124W mutant, which strengthens capsid interdimer interactions, recapitulated the effect of 3711 on capsid assembly. Pyridazinone derivative 3711, a novel chemical entity and HBV inhibitor, may provide a new opportunity to combat chronic HBV infection., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Hepatitis B virus (HBV) belongs to the Hepadnaviridae family. HBsAg, greatly outnumbered mature virion, has been mysterious since the discovery of HBV. A novel benzimidazole derivative, BM601, is identified inhibiting the secretion of HBV virions and HBsAg, with 50% effective concentration of 0.6μM and 1.5μM, as well as 50% cytotoxicity concentration of 24.5μM. It has no effect on transcription, protein production, nucleocapsid formation or intracellular HBV DNA synthesis. Immunofluorescence analysis suggests that BM601 might inhibit virion and HBsAg secretion by interfering surface protein aggregation in trans Golgi apparatus. Furthermore, BM601 does not trigger cellular stress response or affect HBeAg or host protein secretion. We hypothesize that BM601 is a secretion inhibitor functioning at the level of virion and HBsAg secretion pathway., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Aim: To investigate the action of isothiafludine (NZ-4), a derivative of bis-heterocycle tandem pairs from the natural product leucamide A, on the replication cycle of hepatitis B virus (HBV) in vitro and in vivo., Methods: HBV replication cycle was monitored in HepG2.2.15 cells using qPCR, qRT-PCR, and Southern and Northern blotting. HBV protein expression and capsid assembly were detected using Western blotting and native agarose gel electrophoresis analysis. The interaction of pregenomic RNA (pgRNA) and the core protein was investigated by RNA immunoprecipitation. To evaluate the anti-HBV effect of NZ-4 in vivo, DHBV-infected ducks were orally administered NZ-4 (25, 50 or 100 mg·kg⁻¹·d⁻¹) for 15 d., Results: NZ-4 suppressed intracellular HBV replication in HepG2.2.15 cells with an IC₅₀ value of 1.33 μmol/L, whereas the compound inhibited the cell viability with an IC₅₀ value of 50.4 μmol/L. Furthermore, NZ-4 was active against the replication of various drug-resistant HBV mutants, including 3TC/ETV-dual-resistant and ADV-resistant HBV mutants. NZ-4 (5, 10, 20 μmol/L) concentration-dependently reduced the encapsidated HBV pgRNA, resulting in the assembly of replication-deficient capsids in HepG2.2.15 cells. Oral administration of NZ-4 dose-dependently inhibited DHBV DNA replication in the DHBV-infected ducks., Conclusion: NZ-4 inhibits HBV replication by interfering with the interaction between pgRNA and HBcAg in the capsid assembly process, thus increasing the replication-deficient HBV capsids. Such mechanism of action might provide a new therapeutic strategy to combat HBV infection.

Recently, heterocyclic benzimidazole derivatives have been investigated and validated as a promising class of antiviral agents. In this paper, a series of novel thiazolylbenzimidazole derivatives was synthesized and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity on the HepG2.2.15 cell line. Afterwards, the preliminary structure-activity relationship (SAR) was discussed. Compound 8b, with IC(50)  = 1.1 µM and SI > 90.9, was the most promising compound and could be selected as a benchmark compound for further investigation., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of novel benzimidazole derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity in the HepG2.2.15 cell line. The preliminary SAR was discussed. Compound 12a, with IC50<0.41 microM and SI>81.2, was the most promising compound and selected as the benchmark compound for further optimization., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

A series of 1-isopropylsulfonyl-2-amine benzimidazole derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity in the HepG2.2.15 cell line. In general, these derivatives are potent HBV inhibitors (IC(50)<4 microM) with high selectivity indices (SIs>40). Compounds 5b-e, g, j, and 9a were among the most prominent compounds, with IC(50)s of 0.70-2.0 microM and SIs of 41-274. The potent anti-HBV activity and safety profiles of the most promising compounds 5d and j (IC(50)s=0.70 microM, SIs>120) demonstrate the potential of this series of benzimidazoles for the development of new anti-HBV drugs.

A series of novel benzimidazole derivatives was synthesized and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity in vitro. Strong activity against HBV replication and low cytotoxicity were generally observed in these benzimidazoles. The most promising compounds were 12a and 12b, with similar high antiviral potency (IC50 = 0.9 and 0.7 microM, respectively) and remarkable selectivity indices (>1111 and 714, respectively). They were selected for further evaluation as novel HBV inhibitors.