Elsevier

Antiviral Research

Volume 64, Issue 1, October 2004, Pages 1-15
Antiviral Research

Review
Mechanism of viral persistence and resistance to nucleoside and nucleotide analogs in chronic Hepatitis B virus infection

https://doi.org/10.1016/j.antiviral.2004.07.003Get rights and content

Abstract

Chronic Hepatitis B virus (HBV) infections remain a major problem public health problem worldwide, as well as a therapeutic challenge for clinicians. This review focuses on the main viral and host determinants involved in HBV persistence in infected cells. The mechanism of HBV resistance to nucleoside analogs are described as well as the concept for multiple drug therapy and combination with immunostimulatory approaches.

Introduction

Despite the availability of an efficient vaccine, chronic Hepatitis B virus (HBV) infection remains a major public health problem worlwide. Indeed, according to the World Health Organization, more than 400 million people are chronic carriers of the virus, and more than one billion have been in contact with HBV (Lee, 1997). Chronic carriers are exposed to the complications of the disease which include the development of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (Ganem and Prince, 2004). The latter, usually develops after several decades of infection, but represents a major clinical problem in geographical areas where HBV is transmitted vertically.

To combat or prevent these complications, several strategies are available. With respect to prophylaxis, HBV vaccine is safe and efficient. In endemic areas, it was shown that mass vaccination targeting not only adults but also infants was able to decrease the prevalence of HBV infection and the incidence of hepatocellular carcinoma (Chang et al., 1997). In patients who are already chronic carriers, the goals of antiviral therapy are to control viral replication and decrease liver damage to prevent the development of liver cirrhosis and subsequent hepatocellular carcinoma. In clinical practice, treatment relies mainly on the use of IFN alpha, or nucleoside analogs (Hoofnagle and Di Bisceglie, 1997), such as lamivudine or adefovir dipivoxil. However, results of meta-analysis of IFN clinical trials showed that only a minority of patients are long-term responders (approximately 20%) (Wong et al., 1993). Its antiviral effect is also limited by the numerous side effects of this treatment. On the other hand, nucleoside analogs are well tolerated and exhibit an early and potent antiviral effect which is limited by the selection of resistant mutants during long-term therapy (Villeneuve et al., 2003, Zoulim, 2002). Therefore, antiviral therapy of chronic hepatitis B remains a clinical challenge.

Section snippets

The disease and the study models

As HBV replication does not lead by itself to a cytopathic effect, chronic hepatitis B is the result of the ongoing liver injury mediated by the T cell immune response targeting hepatocytes supporting a persistent HBV replication (Bertoletti and Naoumov, 2003, Ganem and Prince, 2004). Our knowledge of the pathobiology of HBV infection has come from clinical studies and from experimental investigations performed in animal models. HBV belongs to the hepadnaviridae family that include animal

Viral replication and persistence

HBV mainly infects hepatocytes, but other cell types including biliary epithelial cells, pancreas, kidney, skin, spleen, bone marrow, peripheral blood mononuclear cells, have been shown to harbor viral genome sequences and to support HBV expression to some extents. Whether these cells represent an extrahepatic reservoir for infectious HBV particle production remains controversial. The HBV replication cycle has been reviewed in detail (for further references, see Ganem and Prince, 2004, Seeger

Mechanisms of spontaneous or antiviral induced viral clearance

The mechanisms of viral clearance have been studied in detail by clinical studies as well as by the use of experimental models. Viral clearance requires the coordinated action of several components of the immune response (Bertoletti and Naoumov, 2003): (1) a cytotoxic TH1 response by CD8 positive cells recognizing infected hepatocytes expressing viral antigens; (2) a non-cytolytic TH1 response whereby the CD8 positive cells produce TH1 cytokines such as IFN gamma, TNF alpha, Interleukin 12 that

Antiviral therapy with nucleoside analogs

The primary mechanism of action of nucleoside analogs is to inhibit viral polymerase activity. The structure of the compounds and their molecular mechanism of action have been reviewed recently (De Clercq, 1999, De Clercq, 2001). Fig. 3 shows their site of action during the viral genome synthesis process.

Lamivudine inhibits viral reverse transcriptase activity, i.e. elongation of viral minus strand DNA, as it is a competitive inhibitor of its natural substrate, dCTP. Furthermore, after its

Mechanism of viral drug resistance

The selection of drug resistant mutants depends on several factors (Fig. 2). Viral persistence is the result of both the long half-life of hepatocytes because of a defective immune response against infected cells, and the persistence of viral cccDNA in infected cells. As the viral polymerase is subjected to a spontaneous error rate, viral mutants are generated and accumulate during the natural history of the disease. The more viable variants in the context of the environmental pressure

Phenotypic analysis of HBV clinical isolates

In the case of HIV therapy, drug resistance testing is now recommended to guide the choice of new drug regimens after the first or multiple treatment failures. In addition to genotypic assays, several phenotypic assays have been developed for HIV and are currently used in clinical practice to monitor drug resistance.

Until recently, no phenotypic drug susceptibility assay had been developed for HBV because of the small number of drug used in clinic, that rendered such assays unnecessary yet and

Prevention of and combating drug resistance

The rationale for combination therapy relies on the following evidence that are based on experimental findings in the hepadnavirus models and on HIV therapy experience (Richman, 2000): (1) simple mutants pre-exist as shown by longitudinal studies of viral polymerase gene sequence, (2) genetic variants harboring multiple mutations have less chance to pre-exist or to occur, (3) re-treatment leads to a rapid re-emergence of resistant mutants although wild type virus re-emerges after first

Perspective

The better knowledge of viral replication should allow the development of new therapeutic concepts (Fig. 1). In this view, novel inhibitors of viral replication are being evaluated in experimental systems. These includes myristilated pre-S1 peptides to compete with the interaction of the virion envelope proteins and the hepatocyte receptor (Urban and Gripon, 2002), peptides or recombinant core proteins exhibiting a trans dominant negative effect on nucleocapsid assembly (von Weizsacker et al.,

Acknowledgement

This work was supported by fundings from the European Community (contract QLRT2001-00977) and was presented in part in the William Prusoff award lecture, at the ICAR, Tucson, May 2004.

References (143)

  • S. Günther et al.

    Naturally occuring variants of hepatitis B virus

    Adv. Virus Res.

    (1999)
  • J.H. Kao et al.

    Hepatitis B genotypes and the response to interferon therapy

    J. Hepatol.

    (2000)
  • C. Klein et al.

    Inhibition of hepatitis B virus replication in vivo by nucleoside analogues and siRNA

    Gastroenterology

    (2003)
  • J. Kock et al.

    Inhibitory effect of adefovir and lamivudine on the initiation of hepatitis B virus infection in primary tupaia hepatocytes

    Hepatology

    (2003)
  • B.E. Korba

    In vitro evaluation of combination therapies against hepatitis B virus replication

    Antivir. Res.

    (1996)
  • B.E. Korba et al.

    Enhanced antiviral benefit of combination therapy with lamivudine and famciclovir against WHV replication in chronic WHV carrier woodchucks

    Antivir. Res.

    (2000)
  • G.K. Lau et al.

    Combination therapy with lamivudine and famciclovir for chronic hepatitis B-infected Chinese patients: a viral dynamics study [see comments]

    Hepatology

    (2000)
  • F. Le Guerhier et al.

    Antiviral effect of adefovir in combination with a DNA vaccine in the duck hepatitis B virus infection model

    J. Hepatol.

    (2003)
  • S.R. Lewin et al.

    Analysis of hepatitis B viral load decline under potent therapy: complex decay profiles observed

    Hepatology

    (2001)
  • W.S. Mason et al.

    Lamivudine therapy of WHV-infected woodchucks

    Virology

    (1998)
  • R.H. Miller et al.

    Hepatitis B virus DNA in nuclear and cytoplasmic fractions of infected human liver

    Virology

    (1984)
  • S. Nafa et al.

    Early detection of viral resistance by determination of Hepatitis B virus polymerase mutations in patients treated by lamivudine for chronic Hepatitis B

    Hepatology

    (2000)
  • D.D. Richman

    The impact of drug resistance on the effectiveness of chemotherapy for chronic hepatitis B

    Hepatology

    (2000)
  • I. Schroder et al.

    Inhibition of human and duck hepatitis B virus by 2′,3′-dideoxy-3′-fluoroguanosine in vitro

    Antivir. Res.

    (1998)
  • B. Seigneres et al.

    Duck hepatitis B virus polymerase gene mutants associated with resistance to lamivudine have a decreased replication capacity in vitro and in vivo

    J. Hepatol.

    (2001)
  • M.I. Allen et al.

    Identification and characterization of mutations in hepatitis B virus resistant to Lamivudine

    Hepatology

    (1998)
  • M.I. Barrasa et al.

    Does a cdc2 kinase-like recognition motif on the core protein of hepadnaviruses regulate assembly and disintegration of capsids

    J. Virol.

    (2001)
  • A. Bartholomeusz et al.

    Mutations in the hepatitis B virus polymerase gene that are associated with resistance to famciclovir and lamivudine

    Int. Antivir. News

    (1997)
  • A. Bartholomeusz et al.

    Comparisons of the HBV and HIV polymerase, and antiviral resistance mutations

    Antivir. Ther.

    (2004)
  • T.M. Block et al.

    Iminosugars as possible broad spectrum anti hepatitis virus agents: the glucovirs and alkovirs

    Antivir. Chem. Chemother.

    (2001)
  • T.M. Block et al.

    Treatment of chronic hepadnavirus infection in a woodchuck animal model with an inhibitor of protein folding and trafficking

    Nat. Med.

    (1998)
  • C. Boni et al.

    Lamivudine treatment can restore T cell responsiveness in chronic hepatitis B [see comments]

    J. Clin. Invest.

    (1998)
  • B. Böttcher et al.

    Peptides that block hepatitis B virus assembly: analysis by cryomicroscopy, mutagenesis and transfection

    EMBO J.

    (1998)
  • E. Bridges et al.

    Use of novel b-L(-)-nucleoside analogues for treatment and prevention of chronic hepatitis B virus infection and hepatocellular carcinoma

    Progress in Liver Diseases

    (1995)
  • V.J. Cavanaugh et al.

    Interleukine-12 inhibits hepatitis B virus replication in transgenic mice

    J. Virol.

    (1997)
  • M.-H. Chang et al.

    Universal hepatitis B vaccination in Taiwan and the incidence of hepatocellular carcinoma in children

    N. Engl. J. Med.

    (1997)
  • D. Colledge et al.

    In vitro antihepadnaviral activities of combinations of penciclovir, lamivudine, and adefovir [in process citation]

    Antimicrob. Agents Chemother.

    (2000)
  • L. Condreay et al.

    (−)-Cis-5-fluoro-1-(2-(hydroxymethyl)-1,3-oxathiolan-5-yl)cytosine (524W91) inhibits hepatitis B virus replication in primary human hepatocytes

    Antimicrob. Agents Chemother.

    (1996)
  • L. Condreay et al.

    Evaluation of the potent anti-HBV agent (−)cis-5-fluoro-1(2-(hydroxymethyl)-1,3-oxathiolan-5-yl) cytosine in a novel in vivo model

    Antimicrob. Agents Chemother.

    (1994)
  • K. Das et al.

    Molecular modeling and biochemical characterization reveal the mechanism of hepatitis B virus polymerase resistance to lamivudine (3TC) and emtricitabine (FTC)

    J. Virol.

    (2001)
  • W.E. Delaney et al.

    Hepatitis B virus replication in human HepG2 cells mediated by hepatitis B virus recombinant baculovirus

    Hepatology

    (1998)
  • W.E.t. Delaney et al.

    Phenylpropenamide derivatives AT-61 and AT-130 inhibit replication of wild-type and lamivudine-resistant strains of hepatitis B virus in vitro

    Antimicrob. Agents Chemother.

    (2002)
  • W.E.t. Delaney et al.

    Cross-resistance testing of antihepadnaviral compounds using novel recombinant baculoviruses which encode drug-resistant strains of hepatitis B virus

    Antimicrob. Agents Chemother.

    (2001)
  • W.E.t Delaney et al.

    The hepatitis B virus polymerase mutation rtV173L is selected during lamivudine therapy and enhances viral replication in vitro

    J. Virol.

    (2003)
  • J. Delmas et al.

    Inhibitory effect of adefovir on viral DNA synthesis and covalently closed circular DNA formation in duck hepatitis B virus-infected hepatocytes in vivo and in vitro

    Antimicrob. Agents Chemother.

    (2002)
  • K. Deres et al.

    Inhibition of hepatitis B virus replication by drug-induced depletion of nucleocapsids

    Science

    (2003)
  • Durantel, D., Carrouée-Durantel, S., Werle-Lapostolle, B., Brunelle, M.N., Pichoud, C., Trépo, C., Zoulim, F., in...
  • D. Fallows et al.

    Mutations in the e sequences of human hepatitis B virus affect both RNA encapsidation and reverse transcription

    J. Virol.

    (1995)
  • G. Fourel et al.

    Frequent activation of N-myc genes by hepadnavirus insertion in woodchuck liver tumors

    Nature

    (1990)
  • I. Fourel et al.

    The carbocyclic analog of 2′-deoxyguanosine induces a prolonged inhibition of duck hepatitis B virus DNA synthesis in primary hepatocyte cultures and in the liver

    J. Virol.

    (1994)
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