Discovery of novel hepatitis B virus (HBV) antivirals and analysis of mechanisms of action of HBV-targeting agents

2017 ◽  
Author(s):  
◽  
Andrew Douglas Huber

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Chronic hepatitis B virus (HBV) infection leads to liver disease, cirrhosis, and hepatocellular carcinoma. Globally, an estimated 50% of all hepatocellular carcinoma cases are linked to chronic HBV infection. More than 240 million people are chronically infected, and there are 0.5-1 million deaths per year due to HBVrelated liver conditions. HBV treatment options rarely cure infections and are associated with adverse side effects that often outweigh the potential benefits of treatment. New treatments, therefore, are highly desired for HBV therapy. Towards this goal, we have developed novel compounds targeting two viral targets and assessed the mechanisms of action by which these compounds act. We have developed systems for the discovery and evaluation of compounds that inhibit 2 distinct steps in the HBV life cycle. Using these systems, we have developed potent inhibitors of HBV replication that have potential to become clinically used HBV drugs. Furthermore, we have used our methods to evaluate which properties of these compounds are likely to result in better viral inhibition. The work described in this thesis has led to at least 2 new compound groups for potential use as HBV antivirals and provides insight into mechanisms by which potent antivirals can be achieved.

2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall

Chronic hepatitis B virus (HBV) infection is a major health burden worldwide, with approximately 257 million people with chronic infection. HBV is a small partially double-stranded DNA virus that replicates within the nucleus of the hepatocyte and commonly leads to chronic infection. Chronic HBV infection can cause cirrhosis, hepatocellular carcinoma, and extrahepatic manifestations such as glomerulonephritis or vasculitis. The latter is due to deposition of circulating immune complex in the different tissues. The natural history of HBV infection can be conceptualized as a spectrum encompassing different phases, including immune tolerance, immune clearance, inactive carrier, and reactivation and resolution. The diagnosis of the different phases of chronic HBV infection relies on various HBV serologies, liver enzyme levels, and histology findings. There are currently eight therapies approved for the treatment of HBV. Tenofovir alafenamide was the most recently approved therapy with a better side effect profile compared with tenofovir disoproxil fumarate. With the recent advances in the basic research in hepatitis B, new treatment options may become available in the near-future. This review contains 9 figures, 11 tables and 80 references Key words: cirrhosis, entecavir, Hepadnaviridae, hepatitis B virus, hepatocellular carcinoma, precore mutation, tenofovir


2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall

Chronic hepatitis B virus (HBV) infection is a major health burden worldwide, with approximately 257 million people with chronic infection. HBV is a small partially double-stranded DNA virus that replicates within the nucleus of the hepatocyte and commonly leads to chronic infection. Chronic HBV infection can cause cirrhosis, hepatocellular carcinoma, and extrahepatic manifestations such as glomerulonephritis or vasculitis. The latter is due to deposition of circulating immune complex in the different tissues. The natural history of HBV infection can be conceptualized as a spectrum encompassing different phases, including immune tolerance, immune clearance, inactive carrier, and reactivation and resolution. The diagnosis of the different phases of chronic HBV infection relies on various HBV serologies, liver enzyme levels, and histology findings. There are currently eight therapies approved for the treatment of HBV. Tenofovir alafenamide was the most recently approved therapy with a better side effect profile compared with tenofovir disoproxil fumarate. With the recent advances in the basic research in hepatitis B, new treatment options may become available in the near-future. This review contains 9 figures, 11 tables and 80 references Key words: cirrhosis, entecavir, Hepadnaviridae, hepatitis B virus, hepatocellular carcinoma, precore mutation, tenofovir


2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall

Chronic hepatitis B virus (HBV) infection is a major health burden worldwide, with approximately 257 million people with chronic infection. HBV is a small partially double-stranded DNA virus that replicates within the nucleus of the hepatocyte and commonly leads to chronic infection. Chronic HBV infection can cause cirrhosis, hepatocellular carcinoma, and extrahepatic manifestations such as glomerulonephritis or vasculitis. The latter is due to deposition of circulating immune complex in the different tissues. The natural history of HBV infection can be conceptualized as a spectrum encompassing different phases, including immune tolerance, immune clearance, inactive carrier, and reactivation and resolution. The diagnosis of the different phases of chronic HBV infection relies on various HBV serologies, liver enzyme levels, and histology findings. There are currently eight therapies approved for the treatment of HBV. Tenofovir alafenamide was the most recently approved therapy with a better side effect profile compared with tenofovir disoproxil fumarate. With the recent advances in the basic research in hepatitis B, new treatment options may become available in the near-future. This review contains 9 figures, 11 tables and 80 references Key words: cirrhosis, entecavir, Hepadnaviridae, hepatitis B virus, hepatocellular carcinoma, precore mutation, tenofovir


2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall

Chronic hepatitis B virus (HBV) infection is a major health burden worldwide, with approximately 257 million people with chronic infection. HBV is a small partially double-stranded DNA virus that replicates within the nucleus of the hepatocyte and commonly leads to chronic infection. Chronic HBV infection can cause cirrhosis, hepatocellular carcinoma, and extrahepatic manifestations such as glomerulonephritis or vasculitis. The latter is due to deposition of circulating immune complex in the different tissues. The natural history of HBV infection can be conceptualized as a spectrum encompassing different phases, including immune tolerance, immune clearance, inactive carrier, and reactivation and resolution. The diagnosis of the different phases of chronic HBV infection relies on various HBV serologies, liver enzyme levels, and histology findings. There are currently eight therapies approved for the treatment of HBV. Tenofovir alafenamide was the most recently approved therapy with a better side effect profile compared with tenofovir disoproxil fumarate. With the recent advances in the basic research in hepatitis B, new treatment options may become available in the near-future. This review contains 9 figures, 11 tables and 80 references Key words: cirrhosis, entecavir, Hepadnaviridae, hepatitis B virus, hepatocellular carcinoma, precore mutation, tenofovir


2012 ◽  
Vol 18 (4) ◽  
pp. 378-387 ◽  
Author(s):  
Xinghui Zhao ◽  
Zhanzhong Zhao ◽  
Junwei Guo ◽  
Peitang Huang ◽  
Xudong Zhu ◽  
...  

Chronic hepatitis B virus (HBV) infection is an independent risk factor for the development of hepatocellular carcinoma (HCC). The HBV HBx gene is frequently identified as an integrant in the chromosomal DNA of patients with HCC. HBx encodes the X protein (HBx), a putative viral oncoprotein that affects transcriptional regulation of several cellular genes. Therefore, HBx may be an ideal target to impede the progression of HBV infection–related HCC. In this study, integrated HBx was transcriptionally downregulated using an artificial transcription factor (ATF). Two three-fingered Cys2-His2 zinc finger (ZF) motifs that specifically recognized two 9-bp DNA sequences regulating HBx expression were identified from a phage-display library. The ZF domains were linked into a six-fingered protein that specified an 18-bp DNA target in the Enhancer I region upstream of HBx. This DNA-binding domain was fused with a Krüppel-associated box (KRAB) transcriptional repression domain to produce an ATF designed to downregulate HBx integrated into the Hep3B HCC cell line. The ATF significantly repressed HBx in a luciferase reporter assay. Stably expressing the ATF in Hep3B cells resulted in significant growth arrest, whereas stably expressing the ATF in an HCC cell line lacking integrated HBx (HepG2) had virtually no effect. The targeted downregulation of integrated HBx is a promising novel approach to inhibiting the progression of HBV infection–related HCC.


2020 ◽  
Author(s):  
Jessica D. Scott ◽  
Silvia Liu ◽  
Kevin C. Klatt ◽  
Zhen Sun ◽  
Qi Guo ◽  
...  

AbstractBackground and AimsThe xenobiotic nuclear receptor Constitutive Androstane Receptor (CAR) is essential for xenobiotic tumor promotion in mouse models. In these models, β-catenin is genetically activated in approximately 80% of tumors. Chronic Hepatitis B Virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC), and β-catenin activation is also frequently activated in HBV-associated HCCs. The goal of this research was to determine whether activation of CAR in a mouse model of chronic HBV infection would result in tumor formation and whether these tumors would display increased β-catenin activation.Approach and ResultsWe treated transgenic mice expressing the HBV X protein (HBx) in hepatocytes with a single dose of the potent CAR agonist TCPOBOP. After 10 months, these mice developed large liver tumors that are characterized by β-catenin nuclear localization and upregulation of β-catenin targets. The β-catenin regulator FoxM1 and the oxidative stress master regulator Nrf2, both of which are CAR gene targets, were also overactivated in tumors. The CAR/HBx tumors share a conserved gene signature with HBV-related human hepatocellular carcinoma.ConclusionsActivation of CAR in the presence of HBx results in tumors with strong β-catenin activation. The mouse model we have described reflects the gene expression patterns seen in human HBV-associated HCC and presents an attractive basis for future studies.


1992 ◽  
Vol 5 (3) ◽  
pp. 275-301 ◽  
Author(s):  
M Feitelson

For many years, epidemiological studies have demonstrated a strong link between chronic hepatitis B virus (HBV) infection and the development of primary hepatocellular carcinoma (PHC). Other hepatocarcinogens such as hepatitis C virus and aflatoxin also contribute to hepatocarcinogenesis either in conjunction with HBV infection or alone. Cellular and molecular biological studies are providing explanations for the HBV-PHC relationship, and models are now being formulated to further test the relative importance of various factors such as viral DNA integration, activation of oncogenes, genetic instability, loss of tumor suppressor genes, and trans-activating properties of HBV to the pathogenesis of PHC. Further research will probably define more than a single mechanism whereby chronic HBV infection results in PHC.


Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 945 ◽  
Author(s):  
Chiao-Fang Teng ◽  
Han-Chieh Wu ◽  
Ih-Jen Su ◽  
Long-Bin Jeng

Chronic hepatitis B virus (HBV) infection is a major risk factor for the development of hepatocellular carcinoma (HCC), the leading cause of cancer-related death worldwide. Despite progress in the prevention and therapy of HCC, high incidence and recurrence rates of HCC remain big threats, resulting in poor patient survival. Effective biomarkers and targets of HCC are therefore urgently needed for better management and to improve patient outcomes. Pre-S mutants have been well demonstrated as HBV oncoproteins that play important roles in HCC development through activation of multiple oncogenic signal pathways in hepatocytes, in vitro and in vivo. The presence of pre-S mutants in patients with chronic HBV infection and HBV-related HCC has been associated with a significantly higher risk of HCC development and recurrence after curative surgical resection, respectively. In this review, we summarize the roles of pre-S mutants as biomarkers for predicting HBV-related HCC development and recurrence, and highlight the pre-S mutants-activated oncogenic signal pathways as potential targets for preventing HBV-related HCC development.


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