Clinical stage drugs targeting inhibitor of apoptosis proteins purge episomal Hepatitis B viral genome in preclinical models

Michelle P Clark,Linda Earnest,Marc Pellegrini,Shahla Romal,Michael D Stutz,Peter Revill,Joseph Torresi,Norbert Wiedemann,Margaret Littlejohn,Liana Mackiewicz,Vitina Sozzi,Tokameh Mahmoudi,Hans Netter ,Sang Hoon Ahn ,Trang Huynh ,Hugh S Mason ,Bang Manh Tran ,Shringar Rao,Elizabeth Vincan,Gregor Ebert

doi:10.1038/s41419-021-03924-0

Abstract

A major unmet clinical need is a therapeutic capable of removing hepatitis B virus (HBV) genome from the liver of infected individuals to reduce their risk of developing liver cancer. A strategy to deliver such a therapy could utilize the ability to target and promote apoptosis of infected hepatocytes. Presently there is no clinically relevant strategy that has been shown to effectively remove persistent episomal covalently closed circular HBV DNA (cccDNA) from the nucleus of hepatocytes. We used linearized single genome length HBV DNA of various genotypes to establish a cccDNA-like reservoir in immunocompetent mice and showed that clinical-stage orally administered drugs that antagonize the function of cellular inhibitor of apoptosis proteins can eliminate HBV replication and episomal HBV genome in the liver. Primary human liver organoid models were used to confirm the clinical relevance of these results. This study underscores a clinically tenable strategy for the potential elimination of chronic HBV reservoirs in patients.

Highlights

260 million people are chronically infected with hepatitis B virus (HBV) and are at increased risk of developing liver cancer compared to the general population [1]
Single length HBV DNA ‘monomers’ generate closed circular HBV DNA (cccDNA)-like molecules in HepG2 cells and permit viral replication We first assessed the ability of linearized HBV 1.0 mers to form cccDNA in HepG2 cells
We PCR-amplified HBV DNA template molecules based on previously characterized clones isolated from patient serum or cell culture-derived [28] and performed SapI endonuclease digestion according to ‘Gunther-PCR’ protocols [29] (Fig. 1A)

Summary

Introduction

260 million people are chronically infected with HBV and are at increased risk of developing liver cancer compared to the general population [1]. A hallmark of HBV infection is the generation of a stable persistent cccDNA viral episome, referred to as a minichromosome, in the nucleus of infected hepatocytes. HBV cccDNA is the template for the transcription of HBV RNAs and is an integral component of the viral replicative lifecycle. No drugs have been shown to effectively eliminate HBV cccDNA which is considered to be a major obstacle to curing chronic HBV infection and reducing the risk of hepatocellular carcinoma [2]. The ultimate goal is to develop strategies that efficiently eliminate HBV cccDNA in an effort to potentially cure chronic HBV infection [3]

Methods

Results

Conclusion