Role and Functional Domain of Hepatitis B Virus X Protein in Regulating HBV Transcription and Replication in Vitro and in Vivo

AbstractHepatitis B x protein (HBx) affects cellular protein expression and participates in the tumorigenesis and progression of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Metabolic reprogramming contributed to the HCC development, but its role in HBV-related HCC remains largely unclear. Tyrosine-protein phosphatase nonreceptor type 13 (PTPN13) is a significant regulator in tumor development, however, its specific role in hepatocarcinogenesis remains to be explored. Here, we found that decreased PTPN13 expression was associated with HBV/HBx. Patients with low PTPN13 expression showed a poor prognosis. Functional assays revealed that PTPN13 inhibited proliferation and tumorigenesis in vitro and in vivo. Further mechanistic studies indicated that HBx inhibited PTPN13 expression by upregulating the expression of DNMT3A and interacting with DNMT3A. Furthermore, we found that DNMT3A bound to the PTPN13 promoter (−343 to −313 bp) in an epigenetically controlled manner associated with elevated DNA methylation and then inhibited PTPN13 transcription. In addition, we identified IGF2BP1 as a novel PTPN13-interacting gene and demonstrated that PTPN13 influences c-Myc expression by directly and competitively binding to IGF2BP1 to decrease the intracellular concentration of functional IGF2BP1. Overexpressing PTPN13 promoted c-Myc mRNA degradation independent of the protein tyrosine phosphatase (PTP) activity of PTPN13. Importantly, we discovered that the PTPN13-IGF2BP1-c-Myc axis was important for cancer cell growth through promoting metabolic reprogramming. We verified the significant negative correlations between PTPN13 expression and c-Myc, PSPH, and SLC7A1 expression in clinical HCC tissue samples. In summary, our findings demonstrate that PTPN13 is a novel regulator of HBV-related hepatocarcinogenesis and may play an important role in HCC. PTPN13 may serve as a prognostic marker and therapeutic target in HBV-related HCC patients.

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Stimulation of Cellular Proliferation by Hepatitis B Virus X Protein

Disease Markers ◽

10.1155/2001/571254 ◽

2001 ◽

Vol 17 (3) ◽

pp. 153-157 ◽

Cited By ~ 47

Author(s):

Charles R. Madden ◽

Betty L. Slagle

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Cellular Proliferation ◽

X Protein ◽

Hepatitis Viruses ◽

B Virus ◽

Infected Cells ◽

Proliferation In Vitro

Chronic infection with the hepatitis B virus (HBV) is a known risk factor in the development of human hepatocellular carcinoma (HCC). The HBV-encoded X protein, HBx, has been investigated for properties that may explain its cancer cofactor role in transgenic mouse lines. We discuss here recent data showing that HBx is able to induce hepatocellular proliferation in vitro and in vivo. This property of HBx is predicted to sensitize hepatocytes to other HCC cofactors, including exposure to carcinogens and to other hepatitis viruses. Cellular proliferation is intimately linked to the mechanism(s) by which most tumor-associated viruses transform virus-infected cells. The HBx alteration of the cell cycle provides an additional mechanism by which chronic HBV infection may contribute to HCC.

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Hepatitis B virus X protein promotes proliferation of hepatocellular carcinoma cells by upregulating miR-181b by targeting ING5

Biological Chemistry ◽

10.1515/hsz-2018-0178 ◽

2018 ◽

Vol 399 (6) ◽

pp. 611-619 ◽

Cited By ~ 2

Author(s):

Xuhua Xie ◽

Xiaopei Xu ◽

Changyu Sun ◽

Zujiang Yu

Keyword(s):

Hepatocellular Carcinoma ◽

Hepatitis B Virus ◽

Hepatitis B ◽

Cell Lines ◽

Tumor Model ◽

Luciferase Reporter ◽

X Protein ◽

B Virus

Abstract Hepatitis B virus X protein (HBx) played a key role in the development of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Emerging evidence has demonstrated that miR-181b and the inhibitor of growth protein 5 (ING5) participated in the pathophysiological process. However, the regulatory mechanism of HBx remained unknown. The expression of miR-181b and ING5 in HCC tissues and cell lines were examined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell viability was determined using the MTT method following HCC cell lines transfection. The interaction between miR-181b and ING5 was assessed by luciferase reporter assay. The nude mice tumor model was well established to evaluate the role and biological functions of HBx on the progression of HBV-related HCC in vivo. MiR-181b was upregulated and ING5 was downregulated in HCC tissues and cell lines. As suggested by the results from in vitro and in vivo experiments, HBx downregulates the expression of the miR-181b target gene ING5, resulting in the promotion of HCC cell proliferation. HBx accelerates proliferation activity of HCC cells by increasing miR-181b expression via targeting ING5, thereby influencing the progression of HBV-related HCC.

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Different Regions of Hepatitis B Virus X Protein Are Required for Enhancement of bZip-Mediated Transactivation versus Transrepression

Journal of Virology ◽

10.1128/jvi.74.1.83-90.2000 ◽

2000 ◽

Vol 74 (1) ◽

pp. 83-90 ◽

Cited By ~ 27

Author(s):

Sangeeta Barnabas ◽

Ourania M. Andrisani

Keyword(s):

Amino Acid ◽

Hepatitis B Virus ◽

Hepatitis B ◽

Deletion Mutants ◽

Amino Acid Residues ◽

X Protein ◽

Amino Acid Region ◽

B Virus

ABSTRACT The hepatitis B virus X protein (pX) interacts directly with the bZip transactivator CREB and the bZip repressors ICERIIγ and ATF3, increasing their DNA-binding affinity in vitro and their transcriptional efficacy in vivo. However, the mechanism of bZip-pX interaction and of the pX-mediated increase in the bZip transcriptional efficacy remains to be understood. In this study with deletion mutants of pX, we delineated a 67-amino-acid region spanning residues 49 to 115 required for direct CREB, ATF3, and ICER IIγ interaction in vitro and in vivo and increased bZip/CRE binding in vitro. Transient transfections of the pX deletion mutants in AML12 hepatocytes demonstrate that pX49–115 is as effective as the full-length pX in enhancing the ATF3- and ICERIIγ-mediated transrepression. However, this pX region is inactive in increasing the transactivation efficacy of CREB; additional amino acid residues present in pX49–140are required to mediate the increased transactivation efficacy of CREB in vivo. This requirement for different regions of pX in affecting CREB transactivation suggests that amino acid residues 115 to 140 integrate additional events in effecting pX-mediated transactivation, such as concomitant interactions with select components of the basal transcriptional apparatus.

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Effect of 3′-azido-3′-deoxythymidine on replication of duck hepatitis B virus in vivo and in vitro

Journal of Medical Virology ◽

10.1002/jmv.1890290405 ◽

1989 ◽

Vol 29 (4) ◽

pp. 244-248 ◽

Cited By ~ 17

Author(s):

Hideaki Haritani ◽

Toshikazu Uchida ◽

Yasunori Okuda ◽

Toshio Shikata

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Duck Hepatitis B Virus ◽

Duck Hepatitis ◽

B Virus

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In vitro and in vivo anti-hepatitis B virus activities of the lignan nirtetralin B isolated from Phyllanthus niruri L.

Journal of Ethnopharmacology ◽

10.1016/j.jep.2014.09.019 ◽

2014 ◽

Vol 157 ◽

pp. 62-68 ◽

Cited By ~ 25

Author(s):

Sheng Liu ◽

Wanxing Wei ◽

Yubin Li ◽

Xing Lin ◽

Kaichuang Shi ◽

...

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Phyllanthus Niruri ◽

B Virus

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Suppression of hepatitis B virus antigen production and replication by wild-type HBV dependently replicating HBV shRNA vectors in vitro and in vivo

Antiviral Research ◽

10.1016/j.antiviral.2016.08.007 ◽

2016 ◽

Vol 134 ◽

pp. 117-129 ◽

Cited By ~ 7

Author(s):

Baosheng Li ◽

Shuo Sun ◽

Minran Li ◽

Xin Cheng ◽

Haijun Li ◽

...

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Virus Antigen ◽

Wild Type ◽

Antigen Production ◽

B Virus

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Binding of nuclear factor EF-C to a functional domain of the hepatitis B virus enhancer region

Molecular and Cellular Biology ◽

10.1128/mcb.9.7.2787-2797.1989 ◽

1989 ◽

Vol 9 (7) ◽

pp. 2787-2797

Author(s):

P Ostapchuk ◽

G Scheirle ◽

P Hearing

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Inverted Repeat ◽

Functional Domain ◽

Nuclear Factor ◽

Transcriptional Enhancer ◽

Base Pairs ◽

Enhancer Region ◽

B Virus

Nuclear factor EF-C is present in extracts prepared from human HepG2 liver cells and from other, nonliver cell lines and binds to the hepatitis B virus and polyomavirus transcriptional enhancer regions in vitro. An inverted repeat (5'-GTTGCNNNGCAAC-3') is located within both binding regions. Diethyl pyrocarbonate interference binding assays and competition binding experiments using altered binding sites demonstrated that EF-C contacts symmetrical nucleotides within the inverted repeat. Mutations that changed the length of the spacer region between the arms of the inverted repeat were introduced in the hepatitis enhancer region. Introduction of 1 or 2 base pairs between the repeats did not affect EF-C binding, but deletion of 1 base pair or introduction of 3 to 9 base pairs reduced binding dramatically. Introduction of 10 base pairs restored partial EF-C binding ability. These and other results suggest that EF-C binding is stabilized by dimerization. In vivo assays for enhancer function using these mutants demonstrated that the EF-C binding site is a functional and important component of the hepatitis B virus enhancer region.

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Anti-Hepatitis B Virus Activity of Esculetin from Microsorium fortunei In Vitro and In Vivo

Molecules ◽

10.3390/molecules24193475 ◽

2019 ◽

Vol 24 (19) ◽

pp. 3475 ◽

Cited By ~ 3

Author(s):

Si-Xin Huang ◽

Jun-Fei Mou ◽

Qin Luo ◽

Qing-Hu Mo ◽

Xian-Li Zhou ◽

...

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Hepatitis B Surface Antigen ◽

Antiviral Drug ◽

Liver Carcinoma ◽

Dependent Manner ◽

Duck Hepatitis ◽

B Virus

Coumarins are widely present in a variety of plants and have a variety of pharmacological activities. In this study, we isolated a coumarin compound from Microsorium fortunei (Moore) Ching; the compound was identified as esculetin by hydrogen and carbon spectroscopy. Its anti-hepatitis B virus (HBV) activity was investigated in vitro and in vivo. In the human hepatocellular liver carcinoma 2.2.15 cell line (HepG2.2.15) transfected with HBV, esculetin effecting inhibited the expression of the HBV antigens and HBV DNA in vitro. Esculetin inhibited the expression of Hepatitis B virus X (HBx) protein in a dose-dependent manner. In the ducklings infected with duck hepatitis B virus (DHBV), the levels of DHBV DNA, duck hepatitis B surface antigen (DHBsAg), duck hepatitis B e-antigen (DHBeAg), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) decreased significantly after esculetin treatment. Summing up the above, the results suggest that esculetin efficiently inhibits HBV replication both in vitro and in vivo, which provides an opportunity for further development of esculetin as antiviral drug.

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