scholarly journals Creation of a Six-fingered Artificial Transcription Factor That Represses the Hepatitis B Virus HBx Gene Integrated into a Human Hepatocellular Carcinoma Cell Line

2012 ◽  
Vol 18 (4) ◽  
pp. 378-387 ◽  
Author(s):  
Xinghui Zhao ◽  
Zhanzhong Zhao ◽  
Junwei Guo ◽  
Peitang Huang ◽  
Xudong Zhu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Transcription Factor ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Cell Line ◽  
Hbv Infection ◽  
Luciferase Reporter ◽  
Artificial Transcription Factor ◽  
Chronic Hepatitis B Virus ◽  
B Virus

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.

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

2017 ◽  
Author(s):  
◽  
Andrew Douglas Huber
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Treatment Options ◽  
Mechanisms Of Action ◽  
Hbv Infection ◽  
Viral Inhibition ◽  
University Of Missouri ◽  
Chronic Hepatitis B Virus ◽  
B Virus

[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.

Hepatitis B Virus

2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Chronic Infection ◽  
Treatment Options ◽  
Hbv Infection ◽  
Chronic Hbv Infection ◽  
Chronic Hepatitis B Virus ◽  
B Virus ◽  
Chronic Hbv

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

Hepatitis B Virus

2021 ◽  
Author(s):  
Ming V. Lin ◽  
April Wall
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Chronic Infection ◽  
Treatment Options ◽  
Hbv Infection ◽  
Chronic Hbv Infection ◽  
Chronic Hepatitis B Virus ◽  
B Virus ◽  
Chronic Hbv

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

scholarly journals Constitutive Androstane Receptor and Hepatitis B Virus X Protein Cooperatively Induce β-catenin-Activated Liver Tumors

2020 ◽  
Author(s):  
Jessica D. Scott ◽  
Silvia Liu ◽  
Kevin C. Klatt ◽  
Zhen Sun ◽  
Qi Guo ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Mouse Model ◽  
Liver Tumors ◽  
Constitutive Androstane Receptor ◽  
Hbv Infection ◽  
X Protein ◽  
Chronic Hepatitis B Virus ◽  
B Virus

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.

scholarly journals Hepatitis B Virus X Protein Increases 8-Oxo-7,8-Dihydro-2ʹ-Deoxyguanosine (8-Oxodg) Level via Repressing MTH1/ MTH2 Expression in Hepatocytes

2018 ◽  
Vol 51 (1) ◽  
pp. 80-96 ◽  
Author(s):  
Yan-Ting Lin ◽  
Wei Liu ◽  
Yun He ◽  
Yun-Li Wu ◽  
Wan-Nan Chen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Transgenic Mice ◽  
Hbv Infection ◽  
Luciferase Reporter ◽  
Sequencing Analysis ◽  
X Protein ◽  
Chronic Hepatitis B Virus ◽  
B Virus

Background/Aims: Chronic hepatitis B virus (HBV) infection markedly increases the risk of development of hepatocellular carcinoma (HCC). Among the seven viral proteins that HBV encodes, HBV X protein (HBx) appears to have the most oncogenic potential. The mitochondria-associated HBx can induce oxidative stress in hepatocytes, leading to the production of abundant reactive oxygen species (ROS). High levels of ROS usually induce oxidative DNA damage and 8-hydroxy-2-deoxyguanosine (8-OHdG), also known as 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG), which is one of the major products of DNA oxidation and an important biomarker for oxidative stress and carcinogenesis. Cells have evolved a mechanism to prevent oxidized nucleotides from their incorporation into DNA through nucleotide pool sanitization enzymes of MTH1 (NUDT1), MTH2 (NUDT15), MTH3 (NUDT18) and NUDT5. However, little is known as to whether HBx can regulate the expression of those enzymes and modulate the formation and accumulation of 8-oxodG in hepatocytes. Methods: The level of 8-oxodG was assessed by ELISA in stable HBV-producing hepatoma cell lines, an HBV infectious mouse model, HBV and HBx transgenic mice and HBV-infected patients versus their respective controls. Expression of MTH1, MTH2, MTH3 and NUDT5 was determined by a real-time quantitative PCR and western blot analysis. Transcriptional regulation of MTH1 and MTH2 expression by HBx and the effect of HBx on MTH1 and MTH2 promoter hypermethylation were examined using a luciferase reporter assay and bisulfite sequencing analysis. Results: In comparison with controls, significantly higher levels of 8-oxodG were detected in the genome and culture supernatant of stable HBV-producing HepG2.2.15 cells, in the sera and liver tissues of HBV infectious mice and HBV or HBx transgenic mice, and in the sera of HBV-infected patients. Expression of HBx in hepatocytes significantly increased 8-oxodG level and reduced the expression of MTH1 and MTH2 at both mRNA and protein levels. It was also demonstrated that HBx markedly attenuated the MTH1 or MTH2 promoter activities through hypermethylation. Furthermore, enhancement of 8-oxodG production by HBx was reversible by overexpression of MTH1 and MTH2. Conclusion: Our data show that HBx expression results in the accumulation of 8-oxodG in hepatocytes through inhibiting the expression of MTH1 and MTH2. This may implicate that HBx may act as a tumor promoter through facilitating the mutational potential of 8-oxodG thus connecting a possible link between HBV infection and liver carcinogenesis.

scholarly journals Hepatitis B virus infection and primary hepatocellular carcinoma.

1992 ◽  
Vol 5 (3) ◽  
pp. 275-301 ◽  
Author(s):  
M Feitelson
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Epidemiological Studies ◽  
Hbv Infection ◽  
Primary Hepatocellular Carcinoma ◽  
Biological Studies ◽  
Chronic Hepatitis B Virus ◽  
B Virus ◽  
Viral Dna Integration

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.

scholarly journals Hepatitis B Virus Pre-S Mutants as Biomarkers and Targets for the Development and Recurrence of Hepatocellular Carcinoma

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 945 ◽  
Author(s):  
Chiao-Fang Teng ◽  
Han-Chieh Wu ◽  
Ih-Jen Su ◽  
Long-Bin Jeng
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hbv Infection ◽  
Signal Pathways ◽  
Recurrence Rates ◽  
Chronic Hepatitis B Virus ◽  
B Virus

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.

scholarly journals Impact of Hepatitis B Virus Genetic Variation, Integration, and Lymphotropism in Antiviral Treatment and Oncogenesis

2020 ◽  
Vol 8 (10) ◽  
pp. 1470
Author(s):  
Keith C.K. Lau ◽  
Kelly W. Burak ◽  
Carla S. Coffin
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Treatment ◽  
Lymphoid Cells ◽  
Hbv Infection ◽  
Dynamic Nature ◽  
Chronic Hepatitis B Virus ◽  
B Virus ◽  
Chronic Hbv

Chronic Hepatitis B Virus (HBV) infection poses a significant global health burden. Although, effective treatment and vaccinations against HBV are available, challenges still exist, particularly in the development of curative therapies. The dynamic nature and unique features of HBV such as viral variants, integration of HBV DNA into host chromosomes, and extrahepatic reservoirs are considerations towards understanding the virus biology and developing improved anti-HBV treatments. In this review, we highlight the importance of these viral characteristics in the context of treatment and oncogenesis. Viral genotype and genetic variants can serve as important predictive factors for therapeutic response and outcomes in addition to oncogenic risk. HBV integration, particularly in coding genes, is implicated in the development of hepatocellular carcinoma. Furthermore, we will discuss emerging research that has identified various HBV nucleic acids and infection markers within extrahepatic sites (lymphoid cells). Intriguingly, the presence of hepatocellular carcinoma (HCC)-associated HBV variants and viral integration within the lymphoid cells may contribute towards the development of extrahepatic malignancies. Improved understanding of these HBV characteristics will enhance the development of a cure for chronic HBV infection.

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