scholarly journals Penciclovir is a selective inhibitor of hepatitis B virus replication in cultured human hepatoblastoma cells.

1996 ◽  
Vol 40 (5) ◽  
pp. 1282-1284 ◽  
Author(s):  
B E Korba ◽  
M R Boyd
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Agent ◽  
Hbv Dna ◽  
Selective Inhibitor ◽  
Hbv Replication ◽  
Virion Release ◽  
B Virus ◽  
Immunodeficiency Virus ◽  
Untreated Culture

Penciclovir [9-(4-hydroxy-3-hydroxymethylbut-1-yI)guanine], an effective antiherpesvirus agent, was found to be a potent and selective antiviral agent against intracellular hepatitis B virus (HBV) replication (drug concentration at which a 10-fold decrease in HBV DNA from the average level in an untreated culture was observed [EC90], 1.6 microM) and extracellular virion release (EC90, 0.7 microM) by cultured human hepatoblastoma (2.2.15) cells. Acyclovir and three other related 9-alkoxypurines with activity against either herpesviruses or human immunodeficiency virus were uniformly inactive against HBV. The activity of penciclovir is discussed in relation to recent findings related to its mode of action against HBV.

scholarly journals Rebound of Hepatitis B Virus Replication in HepG2 Cells after Cessation of Antiviral Treatment

2002 ◽  
Vol 76 (16) ◽  
pp. 8148-8160 ◽  
Author(s):  
Ayman M. Abdelhamed ◽  
Colleen M. Kelley ◽  
Thomas G. Miller ◽  
Phillip A. Furman ◽  
Harriet C. Isom
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Drug Treatment ◽  
Time Course ◽  
Antiviral Treatment ◽  
Recombinant Baculovirus ◽  
Antiviral Agent ◽  
Hbv Dna ◽  
Hbv Replication ◽  
B Virus

ABSTRACT Treatment of patients with lamivudine (3TC) results in loss of detectable levels of hepatitis B virus (HBV) DNA from serum; however, the relapse rate, with regard to both reappearance of virus in the bloodstream and hepatic inflammation, is high when therapy is terminated. Although the rebound observed in patients has also been seen in animal hepadnavirus models, rebound has not been analyzed in an in vitro cell culture system. In this study, we used the HBV recombinant baculovirus/HepG2 system to measure the time course of antiviral agent-mediated loss of HBV replication as well as the time course and magnitude of HBV production after release from antiviral treatment. Because of the sensitivity of the system, it was possible to measure secreted virions, intracellular replicative intermediates, and nuclear non-protein-bound HBV DNA and separately analyze individual species of DNA, such as single-stranded HBV DNA compared to the double-stranded form and relaxed circular compared to covalently closed circular HBV DNA. We first determined that HBV replication in the HBV recombinant baculovirus/HepG2 system could proceed for at least 35 days, with a 30-day plateau level of replication, making it possible to study antiviral agent-mediated loss of HBV followed by rebound after cessation of drug treatment. All HBV DNA species decreased in a time-dependent fashion following antiviral treatment, but the magnitude of decline differed for each HBV DNA species, with the covalently closed circular form of HBV DNA being the most resistant to drug therapy. When drug treatment ceased, HBV DNA species reappeared with a pattern that recapitulated the initiation of replication, but with a different time course.

scholarly journals Strong and Selective Inhibitors of Hepatitis B Virus Replication among Novel N4-Hydroxy- and 5-Methyl-β-l-Deoxycytidine Analogues

2007 ◽  
Vol 51 (7) ◽  
pp. 2523-2530 ◽  
Author(s):  
E. Matthes ◽  
A. Funk ◽  
I. Krahn ◽  
K. Gaertner ◽  
M. von Janta-Lipinski ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Inhibitory Concentration ◽  
Hbv Dna ◽  
Selective Inhibitor ◽  
Effective Concentration ◽  
Active Inhibitor ◽  
Hbv Replication ◽  
B Virus

ABSTRACT Novel N4-hydroxy- and 5-methyl-modified β-l-deoxycytidine analogues were synthesized and evaluated as anti-hepatitis B virus (HBV) agents. Their in vitro efficiencies were investigated in HepG2.2.15 cells stably transfected with HBV. β-l-2′,3′-Didehydro-2′,3′-dideoxy-N4-hydroxycytidine (β-l-Hyd4C) was most effective in reducing secreted HBV DNA (50% effective concentration [EC50], 0.03 μM), followed by β-l-2′,3′-dideoxy-3′-thia-N4-hydroxycytidine (EC50, 0.51 μM), β-l-2′,3′-dideoxy-N4-hydroxycytidine (EC50, 0.55 μM), and β-l-5-methyl-2′-deoxycytidine (EC50, 0.9 μM). The inhibition of the presumed target, the HBV DNA polymerase, by the triphosphates of some of the β-l-cytidine derivatives was also assessed. In accordance with the cell culture data, β-l-Hyd4C triphosphate was the most active inhibitor, with a 50% inhibitory concentration of 0.21 μM. The cytotoxicities of some of the 4-NHOH-modified β-l-nucleosides were dramatically lower than those of the corresponding cytidine analogues with the unmodified 4-NH2 group. The 50% cytotoxic concentrations for β-l-Hyd4C in HepG2 and HL-60 cells were 2,500 μM and 3,500 μM, respectively. In summary, our results demonstrate that at least β-l-Hyd4C can be recommended as a highly efficient and extremely selective inhibitor of HBV replication for further investigations.

scholarly journals Phosphorothioate Di- and Trinucleotides as a Novel Class of Anti-Hepatitis B Virus Agents

2004 ◽  
Vol 48 (6) ◽  
pp. 2199-2205 ◽  
Author(s):  
Radhakrishnan P. Iyer ◽  
Yi Jin ◽  
Arlene Roland ◽  
John D. Morrey ◽  
Samir Mounir ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Nucleoside Analogs ◽  
Hbv Dna ◽  
Parallel Synthesis ◽  
Hbv Replication ◽  
Long Term Treatment ◽  
B Virus ◽  
Dna Strand

ABSTRACT Several nucleoside analogs are under clinical development for use against hepatitis B virus (HBV). Lamivudine (3TC), a nucleoside analog, and adefovir dipivoxil (ADV), an acyclonucleotide analog, are clinically approved. However, long-term treatment can induce viral resistance, and following the cessation of therapy, viral rebound is frequently observed. There continues to be a need for new antiviral agents with novel mechanisms of action. A library of more than 600 di- and trinucleotide compounds synthesized by parallel synthesis using a combinatorial strategy was screened for potential inhibitors of HBV replication using the chronically HBV-producing cell line 2.2.15. Through an iterative process of synthesis, lead optimization, and screening, three analogs were identified as potent inhibitors of HBV replication: dinucleotides ORI-7246 (drug concentration at which a 10-fold reduction of HBV DNA was observed [EC90], 1.4 μM) and ORI-9020 (EC90, 1.2 μM) and trinucleotide ORI-7170 (EC90, 7.2 μM). These analogs inhibited the replication of both strands of HBV DNA. No suppression of HBV protein synthesis or intracellular core particle formation by these analogs was observed. No inhibition of HBV DNA strand elongation by the analogs or their 5′-triphosphate versions was apparent in in vitro polymerase assays. Although the exact mechanism of action is not yet identified, present data are consistent with an inhibition of the HBV reverse transcriptase-directed priming step prior to elongation of the first viral DNA strand. In transient-transfection assays, these analogs inhibited the replication of 3TC-resistant HBV. Synergistic interactions in combination treatments between the analogs and either 3TC or ADV were observed. These compounds represent a novel class of anti-HBV molecules and warrant further investigation as potential therapeutic agents.

Hepatitis B virus activity in untreated hepatitis B e antigen–negative human immunodeficiency virus–hepatitis B virus co-infected patients from sub-Saharan Africa

2019 ◽  
Vol 113 (8) ◽  
pp. 437-445
Author(s):  
Anders Boyd ◽  
Menan Gerard Kouamé ◽  
Laura Houghtaling ◽  
Raoul Moh ◽  
Delphine Gabillard ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hbv Dna ◽  
Sub Saharan Africa ◽  
Hepatitis B E Antigen ◽  
Hiv Rna ◽  
B Virus ◽  
Immunodeficiency Virus ◽  
Sub Saharan

Abstract Background In human immunodeficiency virus (HIV) and hepatitis B virus (HBV) co-infected patients from sub-Saharan Africa with hepatitis B e antigen (HBeAg)-negative status, data are limited on the evolution of HBV activity when antiretroviral treatment (ART) is absent. Methods A total of 43 HBeAg-negative co-infected patients not indicated for ART (per concomitant World Health Organization recommendations) were followed during participation in a randomized controlled trial in Côte d’Ivoire. Chronic HBeAg-negative phases were classified at yearly visits and defined as ‘infection’ (HBV DNA ≤10 000 copies/mL and normal alanine aminotransferase [ALT]) or ‘hepatitis’ (HBV DNA >10 000 copies/mL and/or above normal ALT). Dispersion in HBV DNA and ALT levels during follow-up was assessed using interquartile range (IQR) regression. Results During a median 25 months (IQR 19–31), 17 (40%) patients consistently had ‘infection’, 5 (12%) consistently had ‘hepatitis’ and 21 (48%) fluctuated between phases. Wider dispersion in HBV DNA over time was associated with higher baseline HIV RNA (p=0.02) and higher baseline HBV DNA levels (p=0.008), while wider dispersion in ALT was associated with higher baseline HIV RNA (p<0.001), higher baseline ALT levels (p=0.02) and baseline hepatitis surface antigen >4.0 log10 IU/mL (p=0.02). Conclusions HBV activity is common with HBeAg-negative status, whose variation is partly linked to HIV replication. Fluctuations in disease phase make it difficult to assess the risk of morbidity and mortality after ART initiation.

scholarly journals Hepatitis B Virus Replication and Release Are Independent of Core Lysine Ubiquitination

2009 ◽  
Vol 83 (10) ◽  
pp. 4923-4933 ◽  
Author(s):  
Mayra L. Garcia ◽  
Rushelle Byfield ◽  
Michael D. Robek
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Ubiquitin Ligase ◽  
Core Protein ◽  
Structural Proteins ◽  
Hbv Replication ◽  
Virion Release ◽  
B Virus ◽  
Lysine Residues ◽  
Ubiquitin Conjugation

ABSTRACT Ubiquitin conjugation to lysine residues regulates a variety of protein functions, including endosomal trafficking and degradation. While ubiquitin plays an important role in the release of many viruses, the requirement for direct ubiquitin conjugation to viral structural proteins is less well understood. Some viral structural proteins require ubiquitin ligase activity, but not ubiquitin conjugation, for efficient release. Recent evidence has shown that, like other viruses, hepatitis B virus (HBV) requires a ubiquitin ligase for release from the infected cell. The HBV core protein contains two lysine residues (K7 and K96), and K96 has been suggested to function as a potential ubiquitin acceptor site based on the fact that previous studies have shown that mutation of this amino acid to alanine blocks HBV release. We therefore reexamined the potential connection between core lysine ubiquitination and HBV replication, protein trafficking, and virion release. In contrast to alanine substitution, we found that mutation of K96 to arginine, which compared to alanine is more conserved but also cannot mediate ubiquitin conjugation, does not affect either virus replication or virion release. We also found that the core lysine mutants display wild-type sensitivity to the antiviral activity of interferon, which demonstrates that ubiquitination of core lysines does not mediate the interferon-induced disruption of HBV capsids. However, mutation of K96 to arginine alters the nuclear-cytoplasmic distribution of core, leading to an accumulation in the nucleolus. In summary, these studies demonstrate that although ubiquitin may regulate the HBV replication cycle, these mechanisms function independently of direct lysine ubiquitination of core protein.

scholarly journals Cellular Pharmacology of the Anti-Hepatitis B Virus Agent β-l-2′,3′-Didehydro-2′,3′-Dideoxy-N4-Hydroxycytidine: Relevance for Activation in HepG2 Cells

2009 ◽  
Vol 54 (1) ◽  
pp. 341-345 ◽  
Author(s):  
E. Matthes ◽  
H. Bünger
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Half Life ◽  
Hepg2 Cells ◽  
Selective Inhibitor ◽  
Cellular Pharmacology ◽  
Hbv Replication ◽  
B Virus ◽  
Drug Free ◽  
Triphosphate Derivatives

ABSTRACT ß-l-2′,3′-Didehydro-2′,3′-dideoxy-N4-hydroxycytidine (l-Hyd4C) was demonstrated to be an effective and highly selective inhibitor of hepatitis B virus (HBV) replication in HepG2.2.15 cells (50% effective dose [ED50] = 0.03 μM; 50% cytotoxic dose [CD50] = 2,500 μM). In the present study, we investigated the intracellular pharmacology of tritiated l-Hyd4C in HepG2 cells. l-[3H]Hyd4C was shown to be phosphorylated extensively and rapidly to the 5′-mono-, 5′-di-, and 5′-triphosphate derivatives. Other metabolites deriving from a reduction or removal of the NHOH group of l-Hyd4C could not be detected, although both reactions were described as the primary catabolic pathways of the stereoisomer ß-d-N4-hydroxycytidine in HepG2 cells. Also, the formation of liponucleotide metabolites, such as the 5′-diphosphocholine derivative of l-Hyd4C, as described for some l-deoxycytidine analogues, seems to be unlikely. After incubation of HepG2 cells with 10 μM l-[3H]Hyd4C for 24 h, the 5′-triphosphate accumulated to 19.4 ± 2.7 pmol/106 cells. The predominant peak belonged to 5-diphosphate, with 43.5 ± 4.3 pmol/106 cells. The intracellular half-life of the 5′-triphosphate was estimated to be 29.7 h. This extended half-life probably reflects a generally low affinity of 5′-phosphorylated l-deoxycytidine derivatives for phosphate-degrading enzymes but may additionally be caused by an efficient rephosphorylation of the 5′-diphosphate during a drug-free incubation. The high 5′-triphosphate level and its extended half-life in HepG2 cells are consistent with the potent antiviral activity of l-Hyd4C.

scholarly journals Hepatocyte Endoplasmic Reticulum Stress Inhibits Hepatitis B Virus Secretion and Delays Intracellular Hepatitis B Virus Clearance After Entecavir Treatment

2021 ◽  
Vol 7 ◽  
Author(s):  
Huan Chen ◽  
Maoyuan Mu ◽  
Qichuan Liu ◽  
Han Hu ◽  
Caiyun Tian ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Er Stress ◽  
Western Blotting ◽  
Hbv Dna ◽  
Translation Initiation Factor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hbv Replication ◽  
B Virus

Background: The aim of this study was to explore the effects of endoplasmic reticulum (ER) stress on hepatitis B virus (HBV) replication and the antiviral effect of entecavir (ETV).Methods: Thapsigargin (TG) and stearic acid (SA) were used to induce ER stress in HepG2.2.15 cells and HepAD38 cells that contained an integrated HBV genome, while ETV was used to inhibit HBV replication. The expression levels of glucose-regulated protein 78 (GRP78) and phosphorylated eukaryotic translation initiation factor 2 subunit alpha (p-eIF2α) were measured by western blotting. Intracellular HBV DNA was determined by qPCR; HBsAg by western blotting; HBV RNA by real-time RT-qPCR; HBsAg and HBeAg in supernatants by enzyme-linked immunosorbent assay (ELISA); and HBV DNA in supernatants by qPCR.Results: TG and SA induced ER stress in HepG2.2.15 cells and HepAD38 cells from 12 to 48 h post treatment. However, 4-phenylbutyric acid (PBA) partly alleviated the TG-induced ER stress. Moreover, TG inhibited HBsAg, HBeAg, and HBV DNA secretion from 12 to 48 h, while different concentrations of SA inhibited HBsAg and HBV DNA secretion at 48 h. TG promoted intracellular HBV DNA and HBsAg accumulation and the transcription of the HBV 3.5-kb mRNA and S mRNA. PBA treatment restored the secretion of HBsAg and HBV DNA. Finally, ER stress accelerated extracellular HBV DNA clearance but delayed intracellular HBV DNA clearance after ETV treatment.Conclusions: Hepatocyte ER stress promoted intracellular HBV DNA and HBsAg accumulation by inhibiting their secretion. Our study also suggested that hepatocyte ER stress delayed intracellular HBV DNA clearance after ETV treatment.

scholarly journals Experimental transfection of Macaca sylvanus with cloned human hepatitis B virus

2002 ◽  
Vol 83 (7) ◽  
pp. 1645-1649 ◽  
Author(s):  
Tarik Gheit ◽  
Souad Sekkat ◽  
Lucyna Cova ◽  
Michèle Chevallier ◽  
Marie Anne Petit ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hbv Dna ◽  
Macaca Sylvanus ◽  
Primate Model ◽  
Virus Particles ◽  
Hbv Replication ◽  
Post Transfection ◽  
B Virus ◽  
Dane Particles

Due to the absence of easily accessible animal models for the study of hepatitis B virus (HBV), the possibility of using Macaca sylvanus, a monkey originating from Morocco, North Africa, was investigated. Three monkeys were intrahepatically inoculated with a replication-competent head-to-tail HBV DNA plasmid dimer construct. The HBV surface antigen and HBV DNA were detected prior to alanine aminotransferase elevation in the serum of two of three HBV-inoculated monkeys at day 2 post-transfection and persisted for several weeks. This indicates that transfected animals developed markers of HBV infection. In addition, electron microscopy of the serum 3 weeks post-transfection showed the presence of virus particles whose shape and size were similar to complete 42 nm HBV Dane particles. Histological examination of liver tissues also revealed pathological changes not observed in uninfected controls, which strongly suggested acute hepatitis. HBV DNA was also detected by PCR in these monkey livers. Taken together, these results indicate that HBV can successfully replicate in this model and that M. sylvanus could be a potentially useful new primate model for the study of HBV replication.

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