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

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.

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

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057112463066 ◽

2012 ◽

Vol 18 (4) ◽

pp. 378-387 ◽

Cited By ~ 7

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.

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

10.1101/2020.08.08.241661 ◽

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.

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Transgenic mice expressing hepatitis B virus X protein are more susceptible to carcinogen induced hepatocarcinogenesis

Experimental and Molecular Pathology ◽

10.1016/j.yexmp.2003.09.001 ◽

2004 ◽

Vol 76 (1) ◽

pp. 44-50 ◽

Cited By ~ 29

Author(s):

Huanzhang Zhu ◽

Yun Wang ◽

Jianquan Chen ◽

Guoxiang Cheng ◽

Jinglun Xue

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Transgenic Mice ◽

X Protein ◽

B Virus

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High prevalence of occult hepatitis C virus infection in patients with chronic hepatitis B virus infection

Journal of Medical Microbiology ◽

10.1099/jmm.0.058297-0 ◽

2013 ◽

Vol 62 (8) ◽

pp. 1235-1238 ◽

Cited By ~ 6

Author(s):

Inmaculada Castillo ◽

Javier Bartolomé ◽

Juan Antonio Quiroga ◽

Vicente Carreño

Keyword(s):

Chronic Hepatitis ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Hepatitis B Virus ◽

Virus Infection ◽

Hepatitis B ◽

Hcv Infection ◽

Hbv Infection ◽

Chronic Hepatitis B Virus ◽

B Virus

Hepatitis C virus (HCV) infection in the absence of detectable antibodies against HCV and of viral RNA in serum is called occult HCV infection. Its prevalence and clinical significance in chronic hepatitis B virus (HBV) infection is unknown. HCV RNA was tested for in the liver samples of 52 patients with chronic HBV infection and 21 (40 %) of them were positive for viral RNA (occult HCV infection). Liver fibrosis was found more frequently and the fibrosis score was significantly higher in patients with occult HCV than in negative ones, suggesting that occult HCV infection may have an impact on the clinical course of HBV infection.

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What are the effects of Radix Sophorae Flavescentis in people with chronic hepatitis B virus (HBV) infection?

Cochrane Clinical Answers ◽

10.1002/cca.2599 ◽

2019 ◽

Author(s):

Jane Burch ◽

Deepak Singh-Ranger

Keyword(s):

Chronic Hepatitis ◽

Hepatitis B Virus ◽

Hepatitis B ◽

Chronic Hepatitis B ◽

Hbv Infection ◽

Chronic Hepatitis B Virus ◽

B Virus

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

10.32469/10355/70421 ◽

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.

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Pregnancy Complicated With Hepatitis B Virus Infection and Preterm Birth: A Retrospective Cohort Study

10.21203/rs.3.rs-152431/v1 ◽

2021 ◽

Author(s):

Shuisen Zheng ◽

Huale Zhang ◽

Rongxin Chen ◽

Jianying Yan ◽

Qing Han

Keyword(s):

Risk Factor ◽

Preterm Birth ◽

Hepatitis B Virus ◽

Hepatitis B ◽

Pregnant Women ◽

Hbv Infection ◽

Confounding Factors ◽

Logistics Regression ◽

Chronic Hepatitis B Virus ◽

B Virus

Abstract Background: We aimed to investigate whether maternal chronic hepatitis B virus (HBV) infection affects preterm birth（PTB) in pregnant women. Methods: We retrospectively analyzed HBV-infected and non-infected pregnant women attending antenatal care at Fujian Provincial Maternity and Child Health Hospital, Fuzhou, China between January 1, 2016 to December 31, 2018. Participants were divided into HBV infection (n = 1302) and control (n = 12813) groups. We compared baseline data, pregnancy and perinatal complications, and preterm delivery outcomes between groups and performed subgroup comparisons and multiple logistics regression analysis to adjust for confounding factors. Results: The incidence of PTBs before 37 weeks was similar between the groups. PTBs before 34 weeks were significantly more among the HBV infection group than among the controls (1.6% VS. 0.8% ; P = 0.003) After adjusting for confounding factors through logistics regression, HBV infection was found to be an independent PTB risk factor before 34 weeks gestation (adjusted odds ratio 1.796; 95% confidence interval[1.071, 3.012]). According to the subgroup analysis based on whether hepatitis B e-antigen (HBeAg) was positive and whether alanine aminotransferase (ALT) levels were normal during the second trimester, PTB was more frequent in HBeAg negative HBV infection before 34 weeks than among controls(1.8% VS. 0.8%). The PTB rate for pregnant women with normal ALT and HBV infection before 34 weeks was higher than that of the controls (1.6% VS. 0.8%) Conclusion HBV infection is an independent risk factor for PTB before 34 weeks. Comprehensive programs focusing on pregnant women with HBV infection would reduce the incidence of adverse outcomes.

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