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Fredsgaard M, Kaniki SEK, Antonopoulou I, Chaturvedi T, Thomsen MH. Phenolic Compounds in Salicornia spp. and Their Potential Therapeutic Effects on H1N1, HBV, HCV, and HIV: A Review. Molecules 2023; 28:5312. [PMID: 37513186 PMCID: PMC10384198 DOI: 10.3390/molecules28145312] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/07/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Despite public health risk mitigation measures and regulation efforts by many countries, regions, and sectors, viral outbreaks remind the world of our vulnerability to biological hazards and the importance of mitigation actions. The saltwater-tolerant plants in the Salicornia genus belonging to the Amaranthaceae family are widely recognized and researched as producers of clinically applicable phytochemicals. The plants in the Salicornia genus contain flavonoids, flavonoid glycosides, and hydroxycinnamic acids, including caffeic acid, ferulic acid, chlorogenic acid, apigenin, kaempferol, quercetin, isorhamnetin, myricetin, isoquercitrin, and myricitrin, which have all been shown to support the antiviral, virucidal, and symptom-suppressing activities. Their potential pharmacological usefulness as therapeutic medicine against viral infections has been suggested in many studies, where recent studies suggest these phenolic compounds may have pharmacological potential as therapeutic medicine against viral infections. This study reviews the antiviral effects, the mechanisms of action, and the potential as antiviral agents of the aforementioned phenolic compounds found in Salicornia spp. against an influenza A strain (H1N1), hepatitis B and C (HBV/HCV), and human immunodeficiency virus 1 (HIV-1), as no other literature has described these effects from the Salicornia genus at the time of publication. This review has the potential to have a significant societal impact by proposing the development of new antiviral nutraceuticals and pharmaceuticals derived from phenolic-rich formulations found in the edible Salicornia spp. These formulations could be utilized as a novel strategy by which to combat viral pandemics caused by H1N1, HBV, HCV, and HIV-1. The findings of this review indicate that isoquercitrin, myricetin, and myricitrin from Salicornia spp. have the potential to exhibit high efficiency in inhibiting viral infections. Myricetin exhibits inhibition of H1N1 plaque formation and reverse transcriptase, as well as integrase integration and cleavage. Isoquercitrin shows excellent neuraminidase inhibition. Myricitrin inhibits HIV-1 in infected cells. Extracts of biomass in the Salicornia genus could contribute to the development of more effective and efficient measures against viral infections and, ultimately, improve public health.
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Affiliation(s)
| | | | - Io Antonopoulou
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187 Luleå, Sweden
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2
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Choudhary HB, Mandlik SK, Mandlik DS. Role of p53 suppression in the pathogenesis of hepatocellular carcinoma. World J Gastrointest Pathophysiol 2023; 14:46-70. [PMID: 37304923 PMCID: PMC10251250 DOI: 10.4291/wjgp.v14.i3.46] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/19/2023] [Accepted: 05/31/2023] [Indexed: 06/01/2023] Open
Abstract
In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.
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Affiliation(s)
- Heena B Choudhary
- Department of Pharmacology, BVDU, Poona College of Pharmacy, Pune 411038, Maharashtra, India
| | - Satish K Mandlik
- Department of Pharmaceutics, BVDU, Poona College of Pharmacy, Pune 411038, Maharashtra, India
| | - Deepa S Mandlik
- Department of Pharmacology, BVDU, Poona College of Pharmacy, Pune 411038, Maharashtra, India
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3
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Gromowski T, Lukacs-Kornek V, Cisowski J. Current view of liver cancer cell-of-origin and proposed mechanisms precluding its proper determination. Cancer Cell Int 2023; 23:3. [PMID: 36609378 PMCID: PMC9824961 DOI: 10.1186/s12935-022-02843-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/30/2022] [Indexed: 01/09/2023] Open
Abstract
Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are devastating primary liver cancers with increasing prevalence in many parts of the world. Despite intense investigation, many aspects of their biology are still largely obscure. For example, numerous studies have tackled the question of the cell-of-origin of primary liver cancers using different experimental approaches; they have not, however, provided a clear and undisputed answer. Here, we will review the evidence from animal models supporting the role of all major types of liver epithelial cells: hepatocytes, cholangiocytes, and their common progenitor as liver cancer cell-of-origin. Moreover, we will also propose mechanisms that promote liver cancer cell plasticity (dedifferentiation, transdifferentiation, and epithelial-to-mesenchymal transition) which may contribute to misinterpretation of the results and which make the issue of liver cancer cell-of-origin particularly complex.
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Affiliation(s)
- Tomasz Gromowski
- grid.5522.00000 0001 2162 9631Department of General Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Veronika Lukacs-Kornek
- grid.10388.320000 0001 2240 3300Institute of Experimental Immunology, University Hospital of the Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | - Jaroslaw Cisowski
- Department of General Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
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4
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Glover A, Zhang Z, Shannon-Lowe C. Deciphering the roles of myeloid derived suppressor cells in viral oncogenesis. Front Immunol 2023; 14:1161848. [PMID: 37033972 PMCID: PMC10076641 DOI: 10.3389/fimmu.2023.1161848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/10/2023] [Indexed: 04/11/2023] Open
Abstract
Myeloid derived suppressor cells (MDSCs) are a heterogenous population of myeloid cells derived from monocyte and granulocyte precursors. They are pathologically expanded in conditions of ongoing inflammation where they function to suppress both innate and adaptive immunity. They are subdivided into three distinct subsets: monocytic (M-) MDSC, polymorphonuclear (or neutrophilic) (PMN-) MDSC and early-stage (e-) MDSC that may exhibit differential function in different pathological scenarios. However, in cancer they are associated with inhibition of the anti-tumour immune response and are universally associated with a poor prognosis. Seven human viruses classified as Group I carcinogenic agents are jointly responsible for nearly one fifth of all human cancers. These viruses represent a large diversity of species, including DNA, RNA and retroviridae. They include the human gammaherpesviruses (Epstein Barr virus (EBV) and Kaposi's Sarcoma-Associated Herpesvirus (KSHV), members of the high-risk human papillomaviruses (HPVs), hepatitis B and C (HBV, HCV), Human T cell leukaemia virus (HTLV-1) and Merkel cell polyomavirus (MCPyV). Each of these viruses encode an array of different oncogenes that perturb numerous cellular pathways that ultimately, over time, lead to cancer. A prerequisite for oncogenesis is therefore establishment of chronic infection whereby the virus persists in the host cells without being eradicated by the antiviral immune response. Although some of the viruses can directly modulate the immune response to enable persistence, a growing body of evidence suggests the immune microenvironment is modulated by expansions of MDSCs, driven by viral persistence and oncogenesis. It is likely these MDSCs play a role in loss of immune recognition and function and it is therefore essential to understand their phenotype and function, particularly given the increasing importance of immunotherapy in the modern arsenal of anti-cancer therapies. This review will discuss the role of MDSCs in viral oncogenesis. In particular we will focus upon the mechanisms thought to drive the MDSC expansions, the subsets expanded and their impact upon the immune microenvironment. Importantly we will explore how MDSCs may modulate current immunotherapies and their impact upon the success of future immune-based therapies.
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Tumor Suppressor p53 Inhibits Hepatitis B Virus Replication by Downregulating HBx via E6AP-Mediated Proteasomal Degradation in Human Hepatocellular Carcinoma Cell Lines. Viruses 2022; 14:v14102313. [PMID: 36298868 PMCID: PMC9609658 DOI: 10.3390/v14102313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
HBx, a multifunctional regulatory protein, plays an essential role in the replication and pathogenesis of the hepatitis B virus (HBV). In this study, we found that in human hepatoma cells, the tumor suppressor p53 downregulates HBx via ubiquitin-dependent proteasomal degradation. p53 transcriptional activity that results from HBV infection was not essential for this effect. This was shown by treatment with a potent p53 inhibitor, pifithrin-α. Instead, we found that p53 facilitated the binding of E6-associated protein (E6AP), which is an E3 ligase, to HBx and induced E6AP-mediated HBx ubiquitination in a ternary complex of p53, E6AP, and HBx. The ability of p53 to induce E6AP-mediated downregulation of HBx and inhibit HBV replication was demonstrated in an in vitro HBV infection system. This study may provide insights into the regulation of HBx and HBV replication, especially with respect to p53 status, which may also help in understanding HBV-associated tumorigenesis in patients.
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Park ES, Dezhbord M, Lee AR, Park BB, Kim KH. Dysregulation of Liver Regeneration by Hepatitis B Virus Infection: Impact on Development of Hepatocellular Carcinoma. Cancers (Basel) 2022; 14:cancers14153566. [PMID: 35892823 PMCID: PMC9329784 DOI: 10.3390/cancers14153566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
The liver is unique in its ability to regenerate in response to damage. The complex process of liver regeneration consists of multiple interactive pathways. About 2 billion people worldwide have been infected with hepatitis B virus (HBV), and HBV causes 686,000 deaths each year due to its complications. Long-term infection with HBV, which causes chronic inflammation, leads to serious liver-related diseases, including cirrhosis and hepatocellular carcinoma. HBV infection has been reported to interfere with the critical mechanisms required for liver regeneration. In this review, the studies on liver tissue characteristics and liver regeneration mechanisms are summarized. Moreover, the inhibitory mechanisms of HBV infection in liver regeneration are investigated. Finally, the association between interrupted liver regeneration and hepatocarcinogenesis, which are both triggered by HBV infection, is outlined. Understanding the fundamental and complex liver regeneration process is expected to provide significant therapeutic advantages for HBV-associated hepatocellular carcinoma.
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Affiliation(s)
- Eun-Sook Park
- Institute of Biomedical Science and Technology, School of Medicine, Konkuk University, Seoul 05029, Korea; (E.-S.P.); (B.B.P.)
| | - Mehrangiz Dezhbord
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
| | - Ah Ram Lee
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
| | - Bo Bae Park
- Institute of Biomedical Science and Technology, School of Medicine, Konkuk University, Seoul 05029, Korea; (E.-S.P.); (B.B.P.)
| | - Kyun-Hwan Kim
- Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (M.D.); (A.R.L.)
- Correspondence: ; Tel.: +82-31-299-6126
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7
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Inactivation of tumor suppressor TAp63 by hepatitis B virus X protein in hepatocellular carcinoma. Chin Med J (Engl) 2022; 135:1728-1733. [PMID: 35950770 PMCID: PMC9509107 DOI: 10.1097/cm9.0000000000002283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The hepatitis B virus X (HBx) protein plays a critical role in the initiation and progression of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). In the early stage of the disease, HBx facilitates tumor onset by inactivating the tumor suppressor p53. The p53-encoding gene, however, is frequently mutated or deleted as the cancer progresses to the late stage and, under such circumstance, the p53 homolog TAp63 can harness HCC growth by transactivating several important p53-target genes. METHODS To determine whether HBx regulates TAp63, we performed co-immunoprecipitation assay, real-time quantitative polymerase chain reaction, immunoblotting, and flow cytometry analysis in p53-null cancer cell lines, Hep3B and H1299. RESULTS HBx interacts with the transactivation domain of TAp63, as HBx was co-immunoprecipitated with TAp63 but not with ΔNp63. The interaction between HBx and TAp63 abolished transcriptional activity of TAp63, as evidenced by the reduction of the levels of its target genes p21 and PUMA , consequently leading to restricted apoptosis and augmented proliferation of HCC cells. CONCLUSION HBV induces progression of HCC that harbors defective p53 by inhibiting the tumor suppressor TAp63.
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8
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Sengupta I, Mondal P, Sengupta A, Mondal A, Singh V, Adhikari S, Dhang S, Roy S, Das C. Epigenetic regulation of Fructose‐1,6‐bisphosphatase 1 by host transcription factor Speckled 110
kDa
during hepatitis B virus infection. FEBS J 2022; 289:6694-6713. [DOI: 10.1111/febs.16544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 05/09/2022] [Accepted: 06/01/2022] [Indexed: 12/17/2022]
Affiliation(s)
- Isha Sengupta
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
| | - Payel Mondal
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhaba National Institute Mumbai India
| | - Amrita Sengupta
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
| | - Atanu Mondal
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhaba National Institute Mumbai India
| | - Vipin Singh
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhaba National Institute Mumbai India
| | - Swagata Adhikari
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhaba National Institute Mumbai India
| | - Sinjini Dhang
- Structural Biology & Bio‐Informatics Division CSIR‐Indian Institute of Chemical Biology Kolkata India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad India
| | - Siddhartha Roy
- Structural Biology & Bio‐Informatics Division CSIR‐Indian Institute of Chemical Biology Kolkata India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad India
| | - Chandrima Das
- Biophysics and Structural Genomics Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhaba National Institute Mumbai India
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9
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Hepatitis B Viral Protein HBx and the Molecular Mechanisms Modulating the Hallmarks of Hepatocellular Carcinoma: A Comprehensive Review. Cells 2022; 11:cells11040741. [PMID: 35203390 PMCID: PMC8870387 DOI: 10.3390/cells11040741] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
With 296 million cases estimated worldwide, chronic hepatitis B virus (HBV) infection is the most common risk factor for hepatocellular carcinoma (HCC). HBV-encoded oncogene X protein (HBx), a key multifunctional regulatory protein, drives viral replication and interferes with several cellular signalling pathways that drive virus-associated hepatocarcinogenesis. This review article provides a comprehensive overview of the role of HBx in modulating the various hallmarks of HCC by supporting tumour initiation, progression, invasion and metastasis. Understanding HBx-mediated dimensions of complexity in driving liver malignancies could provide the key to unlocking novel and repurposed combinatorial therapies to combat HCC.
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10
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Abstract
Hepatitis B virus (HBV) is a hepatotropic virus and an important human pathogen. There are an estimated 296 million people in the world that are chronically infected by this virus, and many of them will develop severe liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). HBV is a small DNA virus that replicates via the reverse transcription pathway. In this review, we summarize the molecular pathways that govern the replication of HBV and its interactions with host cells. We also discuss viral and non-viral factors that are associated with HBV-induced carcinogenesis and pathogenesis, as well as the role of host immune responses in HBV persistence and liver pathogenesis.
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Affiliation(s)
- Yu-Chen Chuang
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
| | - Kuen-Nan Tsai
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
| | - Jing-Hsiung James Ou
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
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11
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Mehta S, Campbell H, Drummond CJ, Li K, Murray K, Slatter T, Bourdon JC, Braithwaite AW. Adaptive homeostasis and the p53 isoform network. EMBO Rep 2021; 22:e53085. [PMID: 34779563 PMCID: PMC8647153 DOI: 10.15252/embr.202153085] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 10/12/2021] [Accepted: 10/28/2021] [Indexed: 12/25/2022] Open
Abstract
All living organisms have developed processes to sense and address environmental changes to maintain a stable internal state (homeostasis). When activated, the p53 tumour suppressor maintains cell and organ integrity and functions in response to homeostasis disruptors (stresses) such as infection, metabolic alterations and cellular damage. Thus, p53 plays a fundamental physiological role in maintaining organismal homeostasis. The TP53 gene encodes a network of proteins (p53 isoforms) with similar and distinct biochemical functions. The p53 network carries out multiple biological activities enabling cooperation between individual cells required for long‐term survival of multicellular organisms (animals) in response to an ever‐changing environment caused by mutation, infection, metabolic alteration or damage. In this review, we suggest that the p53 network has evolved as an adaptive response to pathogen infections and other environmental selection pressures.
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Affiliation(s)
- Sunali Mehta
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Hamish Campbell
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand
| | - Catherine J Drummond
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Kunyu Li
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand
| | - Kaisha Murray
- Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Tania Slatter
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Jean-Christophe Bourdon
- Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Antony W Braithwaite
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
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12
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Bawono RG, Abe T, Qu M, Kuroki D, Deng L, Matsui C, Ryo A, Suzuki T, Matsuura Y, Sugiyama M, Mizokami M, Shimotohno K, Shoji I. HERC5 E3 ligase mediates ISGylation of hepatitis B virus X protein to promote viral replication. J Gen Virol 2021; 102. [PMID: 34661519 DOI: 10.1099/jgv.0.001668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ubiquitin and ubiquitin-like protein modification play important roles in modulating the functions of viral proteins in many viruses. Here we demonstrate that hepatitis B virus (HBV) X protein (HBx) is modified by ISG15, which is a type I IFN-inducible, ubiquitin-like protein; this modification is called ISGylation. Immunoblot analyses revealed that HBx proteins derived from four different HBV genotypes accepted ISGylation in cultured cells. Site-directed mutagenesis revealed that three lysine residues (K91, K95 and K140) on the HBx protein, which are well conserved among all the HBV genotypes, are involved in acceptance of ISGylation. Using expression plasmids encoding three known E3 ligases involved in the ISGylation to different substrates, we found that HERC5 functions as an E3 ligase for HBx-ISGylation. Treatment with type I and type III IFNs resulted in the limited suppression of HBV replication in Hep38.7-Tet cells. When cells were treated with IFN-α, silencing of ISG15 resulted in a marked reduction of HBV replication in Hep38.7-Tet cells, suggesting a role of ISG15 in the resistance to IFN-α. In contrast, the silencing of USP18 (an ISG15 de-conjugating enzyme) increased the HBV replication in Hep38.7-Tet cells. Taken together, these results suggest that the HERC5-mediated ISGylation of HBx protein confers pro-viral functions on HBV replication and participates in the resistance to IFN-α-mediated antiviral activity.
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Affiliation(s)
- Rheza Gandi Bawono
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan.,Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Takayuki Abe
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Mengting Qu
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Daisuke Kuroki
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Lin Deng
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Chieko Matsui
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama, Japan
| | - Tetsuro Suzuki
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Yoshiharu Matsuura
- Center for Infectious Diseases Education and Research (CiDER), Research Institute for Microbial Diseases (RIMD) Osaka University, Osaka, Japan
| | - Masaya Sugiyama
- Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Masashi Mizokami
- Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Kunitada Shimotohno
- Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Ikuo Shoji
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
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13
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Dubey AR, Jagtap YA, Kumar P, Patwa SM, Kinger S, Kumar A, Singh S, Prasad A, Jana NR, Mishra A. Biochemical strategies of E3 ubiquitin ligases target viruses in critical diseases. J Cell Biochem 2021; 123:161-182. [PMID: 34520596 DOI: 10.1002/jcb.30143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/23/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Viruses are known to cause various diseases in human and also infect other species such as animal plants, fungi, and bacteria. Replication of viruses depends upon their interaction with hosts. Human cells are prone to such unwanted viral infections. Disintegration and reconstitution require host machinery and various macromolecules like DNA, RNA, and proteins are invaded by viral particles. E3 ubiquitin ligases are known for their specific function, that is, recognition of their respective substrates for intracellular degradation. Still, we do not understand how ubiquitin proteasome system-based enzymes E3 ubiquitin ligases do their functional interaction with different viruses. Whether E3 ubiquitin ligases help in the elimination of viral components or viruses utilize their molecular capabilities in their intracellular propagation is not clear. The first time our current article comprehends fundamental concepts and new insights on the different viruses and their interaction with various E3 Ubiquitin Ligases. In this review, we highlight the molecular pathomechanism of viruses linked with E3 Ubiquitin Ligases dependent mechanisms. An enhanced understanding of E3 Ubiquitin Ligase-mediated removal of viral proteins may open new therapeutic strategies against viral infections.
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Affiliation(s)
- Ankur R Dubey
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Yuvraj A Jagtap
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Prashant Kumar
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Som M Patwa
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Sumit Kinger
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, India
| | - Sarika Singh
- Department of Neuroscience and Ageing Biology, Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Amit Prasad
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | - Nihar R Jana
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Amit Mishra
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
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14
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McBrearty N, Arzumanyan A, Bichenkov E, Merali S, Merali C, Feitelson M. Short chain fatty acids delay the development of hepatocellular carcinoma in HBx transgenic mice. Neoplasia 2021; 23:529-538. [PMID: 33945993 PMCID: PMC8111251 DOI: 10.1016/j.neo.2021.04.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/12/2021] [Accepted: 04/12/2021] [Indexed: 12/17/2022] Open
Abstract
Chronic infection with hepatitis B virus (HBV) is a major risk factor for the development of hepatocellular carcinoma (HCC). The HBV encoded oncoprotein, HBx, alters the expression of host genes and the activity of multiple signal transduction pathways that contribute to the pathogenesis of HCC by multiple mechanisms independent of HBV replication. However, it is not clear which pathways are the most relevant therapeutic targets in hepatocarcinogenesis. Short chain fatty acids (SCFAs) have strong anti-inflammatory and anti-neoplastic properties, suggesting that they may block the progression of chronic liver disease (CLD) to HCC, thereby identifying the mechanisms relevant to HCC development. This hypothesis was tested in HBx transgenic (HBxTg) mice fed SCFAs. Groups of HBxTg mice were fed with SCFAs or vehicle from 6 to 9 months of age and then assessed for dysplasia, and from 9 to 12 months of age and then assessed for HCC. Livers from 12 month old mice were then analyzed for changes in gene expression by mass spectrometry-based proteomics. SCFA-fed mice had significantly fewer dysplastic and HCC nodules compared to controls at 9 and 12 months, respectively. Pathway analysis of SCFA-fed mice showed down-regulation of signaling pathways altered by HBx in human CLD and HCC, including those involved in inflammation, phosphatidylinositol 3-kinase, epidermal growth factor, and Ras. SCFA treatment promoted increased expression of the tumor suppressor, disabled homolog 2 (DAB2). DAB2 depresses Ras pathway activity, which is constitutively activated by HBx. SCFAs also reduced cell viability in HBx-transfected cell lines in a dose-dependent manner while the viability of primary human hepatocytes was unaffected. These unique findings demonstrate that SCFAs delay the pathogenesis of CLD and development of HCC, and provide insight into some of the underlying mechanisms that are relevant to pathogenesis in that they are responsive to treatment.
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Affiliation(s)
- Noreen McBrearty
- Department of Biology, College of Science and Technology, Philadelphia, PA, USA
| | - Alla Arzumanyan
- Department of Biology, College of Science and Technology, Philadelphia, PA, USA
| | - Eugene Bichenkov
- Department of Biology, College of Science and Technology, Philadelphia, PA, USA
| | - Salim Merali
- Department of Pharmaceutical Sciences, School of Pharmacy, Temple University, Philadelphia, PA, USA
| | - Carmen Merali
- Department of Pharmaceutical Sciences, School of Pharmacy, Temple University, Philadelphia, PA, USA
| | - Mark Feitelson
- Department of Biology, College of Science and Technology, Philadelphia, PA, USA.
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15
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Stadelmayer B, Diederichs A, Chapus F, Rivoire M, Neveu G, Alam A, Fraisse L, Carter K, Testoni B, Zoulim F. Full-length 5'RACE identifies all major HBV transcripts in HBV-infected hepatocytes and patient serum. J Hepatol 2020; 73:40-51. [PMID: 32087349 DOI: 10.1016/j.jhep.2020.01.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS Covalently closed circular DNA (cccDNA) is the episomal form of the HBV genome that stably resides in the nucleus of infected hepatocytes. cccDNA is the template for the transcription of 6 major viral RNAs, i.e. preC, pg, preS1/2, S and HBx RNA. All viral transcripts share the same 3' end and are all to various degrees subsets of each other. Especially under infection conditions, it has been difficult to study in depth the transcription of the different viral transcripts. We thus wanted to develop a method with which we could easily detect the full spectrum of viral RNAs in any lab. METHODS We set up an HBV full-length 5'RACE (rapid amplification of cDNA ends) method with which we measured and characterized the full spectrum of viral RNAs in cell culture and in chronically infected patients. RESULTS In addition to canonical HBx transcripts coding for full-length X, we identified shorter HBx transcripts potentially coding for short X proteins. We showed that interferon-β treatment leads to a strong reduction of preC and pgRNAs but has only a moderate effect on the other viral transcripts. We found pgRNA, 1 spliced pgRNA variant and a variety of HBx transcripts associated with viral particles generated by HepAD38 cells. The different HBx RNAs are both capped and uncapped. Lastly, we identified 3 major categories of circulating RNA species in patients with chronic HBV infection: pgRNA, spliced pgRNA variants and HBx. CONCLUSIONS This HBV full-length 5'RACE method should significantly contribute to the understanding of HBV transcription during the course of infection and therapy and may guide the development of novel therapies aimed at targeting cccDNA. LAY SUMMARY Especially under infection conditions, it has been difficult to study the different hepatitis B virus transcripts in depth. This study introduces a new method that can be used in any standard lab to discriminate all hepatitis B viral transcripts in cell culture and in the serum of patients.
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Affiliation(s)
- Bernd Stadelmayer
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France.
| | - Audrey Diederichs
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fleur Chapus
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Michel Rivoire
- INSERM U1032, Centre Léon Bérard (CLB), 69008 Lyon, France
| | - Gregory Neveu
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Antoine Alam
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Laurent Fraisse
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Kara Carter
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Barbara Testoni
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fabien Zoulim
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France; Hospices Civils de Lyon (HCL), 69002 Lyon, France.
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16
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Lee YM, Kim S, Park RY, Kim YS. Hepatitis B Virus-X Downregulates Expression of Selenium Binding Protein 1. Viruses 2020; 12:v12050565. [PMID: 32443734 PMCID: PMC7291177 DOI: 10.3390/v12050565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023] Open
Abstract
Selenium binding protein 1 (SELENBP1) has been known to be reduced in various types cancer, and epigenetic change is shown to be likely to account for the reduction of SELNEBP1 expression. With cDNA microarray comparative analysis, we found that SELENBP1 is markedly decreased in hepatitis B virus-X (HBx)-expressing cells. To clarify the effect of HBx on SELENBP1 expression, we compared the expression levels of SELENBP1 mRNA and protein by semi-quantitative RT-PCR, Northern blot, and Western blot. As expected, SELENBP1 expression was shown to be reduced in cells expressing HBx, and reporter gene analysis showed that the SELENBP1 promoter is repressed by HBx. In addition, the stepwise deletion of 5′ flanking promoter sequences resulted in a gradual decrease in basal promoter activity and inhibition of SELENBP1 expression by HBx. Moreover, immunohistochemistry on tissue microarrays containing 60 pairs of human liver tissue showed decreased intensity of SELENBP1 in tumor tissues as compared with their matched non-tumor liver tissues. Taken together, our findings suggest that inhibition of SELENBP1 expression by HBx might act as one of the causes in the development of hepatocellular carcinoma caused by HBV infection.
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Affiliation(s)
- Young-Man Lee
- Dasan Undergraduate College, Ajou University, Suwon 16499, Korea;
| | - Soojin Kim
- Graduate School of New Drug Discovery & Development, Chungnam National University, Daejeon 34134, Korea;
| | - Ran-Young Park
- Department of Smart Food & Drugs, Inje University, Gimhae 50834, Korea;
| | - Yeon-Soo Kim
- Graduate School of New Drug Discovery & Development, Chungnam National University, Daejeon 34134, Korea;
- Correspondence: ; Tel.: +82-42-821-8631
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17
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Host Transcription Factors in Hepatitis B Virus RNA Synthesis. Viruses 2020; 12:v12020160. [PMID: 32019103 PMCID: PMC7077322 DOI: 10.3390/v12020160] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 02/06/2023] Open
Abstract
The hepatitis B virus (HBV) chronically infects over 250 million people worldwide and is one of the leading causes of liver cancer and hepatocellular carcinoma. HBV persistence is due in part to the highly stable HBV minichromosome or HBV covalently closed circular DNA (cccDNA) that resides in the nucleus. As HBV replication requires the help of host transcription factors to replicate, focusing on host protein–HBV genome interactions may reveal insights into new drug targets against cccDNA. The structural details on such complexes, however, remain poorly defined. In this review, the current literature regarding host transcription factors’ interactions with HBV cccDNA is discussed.
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18
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Wang F, Shen F, Wang Y, Li Z, Chen J, Yuan Z. Residues Asn118 and Glu119 of hepatitis B virus X protein are critical for HBx-mediated inhibition of RIG-I-MAVS signaling. Virology 2020; 539:92-103. [PMID: 31706164 DOI: 10.1016/j.virol.2019.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/24/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) X protein (HBx) has been reported to counteract the innate immune responses through interfering with the pattern recognition receptors signaling activated by retinoic acid-inducible gene-I (RIG-I)-mitochondrial antiviral signaling protein (MAVS). Here, we showed that, compared to the HBx derived from genotype (gt) A, C and D, HBx of gtB exhibited more potent inhibitory activity on the RIG-I-MAVS-mediated interferon-β promoter activation. Functional analysis of the genotype-associated differences in amino acid sequence and the reciprocal mutation experiments in transient-transfection and infection cell models revealed that HBx with asparagine (N) and glutamic acid (E) at 118-119 positions inhibited RIG-I signaling and interacted with MAVS more efficiently than that with lysine (K) and aspartic acid (D). An impaired RIG-I-induced MAVS aggregation was observed in the presence of HBx-118N119E while MAVS-TRAF3 interaction was not affected. These results implicated that HBx gene heterogeneity may affect the innate immune responses to HBV infection.
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Affiliation(s)
- Fan Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Fang Shen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yang Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Ze Li
- Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jieliang Chen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Zhenghong Yuan
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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19
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Peroxiredoxin 1, a Novel HBx-Interacting Protein, Interacts with Exosome Component 5 and Negatively Regulates Hepatitis B Virus (HBV) Propagation through Degradation of HBV RNA. J Virol 2019; 93:JVI.02203-18. [PMID: 30567989 DOI: 10.1128/jvi.02203-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Hepatitis B virus (HBV) infection is a major risk factor for the development of chronic liver diseases, including cirrhosis and hepatocellular carcinoma (HCC). A growing body of evidence suggests that HBV X protein (HBx) plays a crucial role in viral replication and HCC development. Here, we identified peroxiredoxin 1 (Prdx1), a cellular hydrogen peroxide scavenger, as a novel HBx-interacting protein. Coimmunoprecipitation analysis coupled with site-directed mutagenesis revealed that the region from amino acids 17 to 20 of the HBx, particularly HBx Cys17, is responsible for the interaction with Prdx1. Knockdown of Prdx1 by siRNA significantly increased the levels of intracellular HBV RNA, HBV antigens, and extracellular HBV DNA, whereas knockdown of Prdx1 did not increase the activities of HBV core, enhancer I (Enh1)/X, preS1, and preS2/S promoters. Kinetic analysis of HBV RNA showed that knockdown of Prdx1 inhibited HBV RNA decay, suggesting that Prdx1 reduces HBV RNA levels posttranscriptionally. The RNA coimmunoprecipitation assay revealed that Prdx1 interacted with HBV RNA. The exosome component 5 (Exosc5), a member of the RNA exosome complexes, was coimmunoprecipitated with Prdx1, suggesting its role in regulation of HBV RNA stability. Taken together, these results suggest that Prdx1 and Exosc5 play crucial roles in host defense mechanisms against HBV infection.IMPORTANCE Hepatitis B virus (HBV) infection is a major global health problem. HBx plays important roles in HBV replication and viral carcinogenesis through its interaction with host factors. In this study, we identified Prdx1 as a novel HBx-binding protein. We provide evidence suggesting that Prdx1 promotes HBV RNA decay through interaction with HBV RNA and Exosc5, leading to downregulation of HBV RNA. These results suggest that Prdx1 negatively regulates HBV propagation. Our findings may shed new light on the roles of Prdx1 and Exosc5 in host defense mechanisms in HBV infection.
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20
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Su C, Lin Y, Mao Q, Wu D, Zhu L, Najera I, Garcia-Alcalde F, Niu J. Association study between mannose-binding lectin haplotypes and X gene mutation of hepatitis B virus from treatment naïve patients. Aging (Albany NY) 2017; 8:2862-2870. [PMID: 27824315 PMCID: PMC5191875 DOI: 10.18632/aging.101097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/24/2016] [Indexed: 01/26/2023]
Abstract
Mannose binding lectin (MBL) plays important role in the innate immunity of human. Mutations in the MBL2 gene can significantly change the serum level of MBL, and consequently alter the susceptibility and progression of infectious disease. However, the association between the MBL2 profile and the HBV mutation and quasispecies complexity has not yet been reported. Our approach includes the study of the MBL2 gene genotype as well as ultra-deep sequencing of the HBV viruses obtained from the plasma of 50 treatment naïve patients with chronic HBV infection. We found that the liver function was better among patients within the high MBL2 group with respect to those within the medium/low MBL2 group. Likewise, the number of mutations in the HBV X gene as well as the viral quasispecies complexity were significantly higher in medium/low MBL2 production group. Nucleotide substitution rates were also higher within the medium/low MBL2 production group in all positions described to have an influence in liver cancer development, except for A1499G. In this work we show that the MBL2 profile may have an impact on the HBV X gene mutations as well as on viral quasispecies complexity.
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Affiliation(s)
- Chenghao Su
- Xiamen Center for Disease Control and Prevention, Xiamen, Fujian 361021, China
| | - Yong Lin
- Xiamen Center for Disease Control and Prevention, Xiamen, Fujian 361021, China.,School of Public Health, Fujian Medical University, Fuzhou, Fujian 351022, China
| | - Qianguo Mao
- Xiamen Hospital of Traditional Chinses Medicine, Xiamen, Fujian 361001, China
| | - Daitze Wu
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Shanghai 201203, China
| | - Lina Zhu
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Shanghai 201203, China
| | - Isabel Najera
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Basel 4070, Switzerland
| | - Fernando Garcia-Alcalde
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Basel 4070, Switzerland
| | - Jianjun Niu
- Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, China
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21
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Sengupta I, Das D, Singh SP, Chakravarty R, Das C. Host transcription factor Speckled 110 kDa (Sp110), a nuclear body protein, is hijacked by hepatitis B virus protein X for viral persistence. J Biol Chem 2017; 292:20379-20393. [PMID: 29046350 DOI: 10.1074/jbc.m117.796839] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/13/2017] [Indexed: 12/20/2022] Open
Abstract
Promyelocytic leukemia nuclear bodies (PML-NB) are sub-nuclear organelles that are the hub of numerous proteins. DNA/RNA viruses often hijack the cellular factors resident in PML-NBs to promote their proliferation in host cells. Hepatitis B virus (HBV), belonging to Hepadnaviridae family, remains undetected in early infection as it does not induce the innate immune response and is known to be the cause of several hepatic diseases leading to cirrhosis and hepatocellular carcinoma. The association of PML-NB proteins and HBV is being addressed in a number of recent studies. Here, we report that the PML-NB protein Speckled 110 kDa (Sp110) is SUMO1-modified and undergoes a deSUMOylation-driven release from the PML-NB in the presence of HBV. Intriguingly, Sp110 knockdown significantly reduced viral DNA load in the culture supernatant by activation of the type I interferon-response pathway. Furthermore, we found that Sp110 differentially regulates several direct target genes of hepatitis B virus protein X (HBx), a viral co-factor. Subsequently, we identified Sp110 as a novel interactor of HBx and found this association to be essential for the exit of Sp110 from the PML-NB during HBV infection and HBx recruitment on the promoter of these genes. HBx, in turn, modulates the recruitment of its associated transcription cofactors p300/HDAC1 to these co-regulated genes, thereby altering the host gene expression program in favor of viral persistence. Thus, we report a mechanism by which HBV can evade host immune response by hijacking the PML-NB protein Sp110, and therefore, we propose it to be a novel target for antiviral therapy.
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Affiliation(s)
- Isha Sengupta
- From the Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata-700064
| | - Dipanwita Das
- the Indian Council of Medical Research (ICMR) Virus Unit, Kolkata, Infectious Diseases and Beliaghata General Hospital Campus, Kolkata 700010, and
| | - Shivaram Prasad Singh
- the Kalinga Gastroenterology Foundation, Beam Diagnostics Premises, Cuttack-753001, India
| | - Runu Chakravarty
- the Indian Council of Medical Research (ICMR) Virus Unit, Kolkata, Infectious Diseases and Beliaghata General Hospital Campus, Kolkata 700010, and
| | - Chandrima Das
- From the Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata-700064,
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22
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X protein variants of the autochthonous Latin American hepatitis B virus F genotype promotes human hepatocyte death by the induction of apoptosis and autophagy. Virus Res 2017; 242:156-165. [PMID: 28986109 PMCID: PMC7114566 DOI: 10.1016/j.virusres.2017.09.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 02/07/2023]
Abstract
The impact of BCP mutations on HBV-X biologic activity was analyzed. Genotype F wild type and mutant HBV-X induce apoptosis of human hepatocytes. HBV-X variants modulate the expression of Bcl-2 family proteins. Subgenotypes F1b and F4 HBV-X and variants induce autophagy of human hepatocytes.
The hepatitis B virus X protein (HBV-X) is a multifunctional regulatory protein associated with the pathogenesis of liver disease in chronic HBV infection. Basal core promoter mutations (BCP), associated with the clinical course of chronic HBV infection, affect HBV-X at 130–131 positions. The role of these mutations on HBV-X biological activity remains largely unknown. The aim of this study was to analyze the impact of the presence of different amino acids at 130–131 positions of HBV-X on the biological activity of the protein. Transient expression of wild type and mutant F1b and F4 HBV-X increased cell mortality by the induction of apoptosis in human hepatoma cells. The wild type and mutant HBV-X differentially modulate the expression of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2 and Bcl-X) regulatory proteins of the Bcl-2 family. Furthermore, the expression of HBV-X variants of both subgenotypes induced autophagy of human tumoral hepatocytes. In conclusion, HBV-X variants of the Latin American HBV F genotype promotes human hepatocytes death by the induction of apoptosis and autophagy. The results of this work describe some of the molecular mechanisms by which HBV-X variants contribute to the pathogenesis of liver diseases in the infected liver and help to the biological characterization of genotype F, responsible of the majority of HBV infections in Argentina.
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23
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Zhou X, Shi H, Yang S, Sun P. An efficient rapid system for assaying HBx-mediated transactivation. Biotechnol Lett 2017; 39:1091-1099. [PMID: 28386736 DOI: 10.1007/s10529-017-2334-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/30/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVES To develop a rapid and accurate assay system for screening inhibitors or enhancing agents targeting the transactivation capability of hepatitis B virus X protein (HBx) that activates cellular promoters in host cells to facilitate viral replication. RESULTS We constructed a new GFP-based reporter system which was different from a luciferase-based reporter system. Firstly, a FLAG-tagged HBx gene was inserted into an expression plasmid, resulting in plasmid pHBx. Next, HBx-FLAG was linked to EGFP by the internal ribosome entry site resulting in plasmid pHBxE. The transactivation effect of HBx-flag on cytomegalovirus (CMV) promoter was verified by EGFP expression using fluorescence quantitation and qPCR. Furthermore, the transactivation ability of the HBx gene was quantified by flow cytometry. Finally, this assay system was tested by known regulators of HBx including DDB1, ID1, and P53. As expected, the GFP reporter level in 293T cells changed with the increasing of HBx regulators. Furthermore, the system modeling the function of transactivation repressor in Hep3B, a HBV-integrated cell line. CONCLUSION Collectively, the GFP-based reporter system provides a rapid and accurate approach for analyzing transactivation ability of HBx.
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Affiliation(s)
- Xiaoling Zhou
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Haijun Shi
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Shaozhe Yang
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Pingnan Sun
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China.
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China.
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China.
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Abstract
Liver cancer remains one of the most common human cancers with a high mortality rate. Therapies for hepatocellular carcinoma (HCC) remain ineffective, due to the heterogeneity of HCC with regard to both the etiology and mutation spectrum, as well as its chemotherapy resistant nature; thus surgical resection and liver transplantation remain the gold standard of patient care. The most common etiologies of HCC are extrinsic factors. Humans have multiple defense mechanisms against extrinsic factor-induced carcinogenesis, of which tumor suppressors play crucial roles in preventing normal cells from becoming cancerous. The tumor suppressor p53 is one of the most frequently mutated genes in liver cancer. p53 regulates expression of genes involved in cell cycle progression, cell death, and cellular metabolism to avert tumor development due to carcinogens. This review article mainly summarizes extrinsic factors that induce liver cancer and potentially have etiological association with p53, including aflatoxin B1, vinyl chloride, non-alcoholic fatty liver disease, iron overload, and infection of hepatitis viruses.
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Affiliation(s)
- Tim Link
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Tomoo Iwakuma
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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25
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Schreiner S, Nassal M. A Role for the Host DNA Damage Response in Hepatitis B Virus cccDNA Formation-and Beyond? Viruses 2017; 9:v9050125. [PMID: 28531167 PMCID: PMC5454437 DOI: 10.3390/v9050125] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/12/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection puts more than 250 million people at a greatly increased risk to develop end-stage liver disease. Like all hepadnaviruses, HBV replicates via protein-primed reverse transcription of a pregenomic (pg) RNA, yielding an unusually structured, viral polymerase-linked relaxed-circular (RC) DNA as genome in infectious particles. Upon infection, RC-DNA is converted into nuclear covalently closed circular (ccc) DNA. Associating with cellular proteins into an episomal minichromosome, cccDNA acts as template for new viral RNAs, ensuring formation of progeny virions. Hence, cccDNA represents the viral persistence reservoir that is not directly targeted by current anti-HBV therapeutics. Eliminating cccDNA will thus be at the heart of a cure for chronic hepatitis B. The low production of HBV cccDNA in most experimental models and the associated problems in reliable cccDNA quantitation have long hampered a deeper understanding of cccDNA molecular biology. Recent advancements including cccDNA-dependent cell culture systems have begun to identify select host DNA repair enzymes that HBV usurps for RC-DNA to cccDNA conversion. While this list is bound to grow, it may represent just one facet of a broader interaction with the cellular DNA damage response (DDR), a network of pathways that sense and repair aberrant DNA structures and in the process profoundly affect the cell cycle, up to inducing cell death if repair fails. Given the divergent interactions between other viruses and the DDR it will be intriguing to see how HBV copes with this multipronged host system.
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Affiliation(s)
- Sabrina Schreiner
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg, D-85764 Munich, Germany.
| | - Michael Nassal
- Dept. of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
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Chan C, Thurnherr T, Wang J, Gallart-Palau X, Sze SK, Rozen S, Lee CG. Global re-wiring of p53 transcription regulation by the hepatitis B virus X protein. Mol Oncol 2016; 10:1183-95. [PMID: 27302019 DOI: 10.1016/j.molonc.2016.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The tumour suppressor p53 is a central player in transcription regulation and cell fate determination. By interacting with p53 and altering its sequence-specific binding to the response elements, the hepatitis B virus X protein (HBx) was reported to re-direct p53 regulation of some genes. RESULTS Coupling massively parallel deep sequencing with p53 chromatin immunoprecipitation, we demonstrate that HBx modulates global p53 site selection and that this was strongly influenced by altered interaction with transcription co-factors/co-regulators as well as post-translational modifications. Specifically, HBx attenuated p53-TBP-RB1 transcription complex recruitment and interaction and this was associated with hyper-phosphorylation of p53 at serine 315 by HBx. Concurrently, HBx enhanced p53 DNA occupancy to other response elements either alone by displacing specific transcription factors such as CEBPB and NFkB1, or in complex with distinct interacting co-factors Sp1, JUN and E2F1. Importantly, re-wiring of p53 transcription regulation by HBx was linked to the deregulation of genes involved in cell proliferation and death, suggesting a role of HBx in errant cell fate determination mediated by altered p53 site selection of target genes. CONCLUSIONS Our study thus presents first evidence of global modes of p53 transcription alteration by HBx and provides new insights to understand and potentially curtail the viral oncoprotein.
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Affiliation(s)
- Cheryl Chan
- Division of Medical Sciences, Humphrey Oei Institute of Cancer Research, National Cancer Centre Singapore, Singapore 169610, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore
| | - Thomas Thurnherr
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore; Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Jingbo Wang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Xavier Gallart-Palau
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Steve Rozen
- Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Caroline G Lee
- Division of Medical Sciences, Humphrey Oei Institute of Cancer Research, National Cancer Centre Singapore, Singapore 169610, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore; Duke-NUS Graduate Medical School, Singapore 169857, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
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Zhu M, Guo J, Li W, Lu Y, Fu S, Xie X, Xia H, Dong X, Chen Y, Quan M, Zheng S, Xie K, Li M. Hepatitis B virus X protein induces expression of alpha-fetoprotein and activates PI3K/mTOR signaling pathway in liver cells. Oncotarget 2016; 6:12196-208. [PMID: 25682869 PMCID: PMC4494932 DOI: 10.18632/oncotarget.2906] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/11/2014] [Indexed: 12/28/2022] Open
Abstract
The hepatitis B virus (HBV)-X protein (HBx) induces malignant transformation of liver cells, and elevated expression of alpha-fetoprotein (AFP) is a significant biomarker of hepatocarcinogenesis. However, the role of AFP in HBV-related hepatocarcinogenesis is unclear. In this study, we investigated the regulatory impact of AFP expression on HBx-mediated malignant transformation of human hepatocytes. We found that HBV induced the expression of AFP before that of oncogenes, e.g., Src, Ras and chemokine (C-X-C motif) receptor 4 (CXCR4), and AFP activated protein kinase B (AKT) and mammalian target of rapamycin (mTOR) in HBV-related HCC tissues and in human liver cells transfected with HBx. Cytoplasmic AFP interacted with and inhibited phosphatase and tensin homolog deleted on chromosome 10 (PTEN), activating the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway and promoting mTOR-mediated stimulation of the transcription factor hypoxia inducible factor-1α (HIF-1α), and therefore led to the activation of the promoters of Src, CXCR4, and Ras genes. On the contrary, reduced expression of AFP by siRNA resulted in the repression of p-mTOR, pAKT, Src, CXCR4, and Ras in human malignant liver cells. Taken together, for the first time our study indicates that HBx-induced AFP expression critically promote malignant transformation in liver cells through the activation of PI3K/mTOR signaling.
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Affiliation(s)
- Mingyue Zhu
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Junli Guo
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Department of Gastroenterology, Hepatology & Nutrition, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Wei Li
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Yan Lu
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Shigan Fu
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Xieju Xie
- Department of Physiology and Pathophysiology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Hua Xia
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Xu Dong
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Yi Chen
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
| | - Ming Quan
- Department of Gastroenterology, Hepatology & Nutrition, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Shaojiang Zheng
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Tumor Institute, Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570102, P. R. China
| | - Keping Xie
- Department of Gastroenterology, Hepatology & Nutrition, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mengsen Li
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, Hainan 571199, P. R. China.,Key Laboratory of Molecular Biology, Hainan Medical College, Haikou, Hainan 571199, P. R. China
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28
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Hepatocyte Factor JMJD5 Regulates Hepatitis B Virus Replication through Interaction with HBx. J Virol 2016; 90:3530-42. [PMID: 26792738 DOI: 10.1128/jvi.02776-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/30/2015] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Hepatitis B virus (HBV) is a causative agent for chronic liver diseases such as hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). HBx protein encoded by the HBV genome plays crucial roles not only in pathogenesis but also in replication of HBV. Although HBx has been shown to bind to a number of host proteins, the molecular mechanisms by which HBx regulates HBV replication are largely unknown. In this study, we identified jumonji C-domain-containing 5 (JMJD5) as a novel binding partner of HBx interacting in the cytoplasm. DNA microarray analysis revealed that JMJD5-knockout (JMJD5KO) Huh7 cells exhibited a significant reduction in the expression of transcriptional factors involved in hepatocyte differentiation, such as HNF4A, CEBPA, and FOXA3. We found that hydroxylase activity of JMJD5 participates in the regulation of these transcriptional factors. Moreover, JMJD5KO Huh7 cells exhibited a severe reduction in HBV replication, and complementation of HBx expression failed to rescue replication of a mutant HBV deficient in HBx, suggesting that JMJD5 participates in HBV replication through an interaction with HBx. We also found that replacing Gly(135) with Glu in JMJD5 abrogates binding with HBx and replication of HBV. Moreover, the hydroxylase activity of JMJD5 was crucial for HBV replication. Collectively, these results suggest that direct interaction of JMJD5 with HBx facilitates HBV replication through the hydroxylase activity of JMJD5. IMPORTANCE HBx protein encoded by hepatitis B virus (HBV) plays important roles in pathogenesis and replication of HBV. We identified jumonji C-domain-containing 5 (JMJD5) as a novel binding partner to HBx. JMJD5 was shown to regulate several transcriptional factors to maintain hepatocyte function. Although HBx had been shown to support HBV replication, deficiency of JMJD5 abolished contribution of HBx in HBV replication, suggesting that HBx-mediated HBV replication is largely dependent on JMJD5. We showed that hydroxylase activity of JMJD5 in the C terminus region is crucial for expression of HNF4A and replication of HBV. Furthermore, a mutant JMJD5 with Gly(135) replaced by Glu failed to interact with HBx and to rescue the replication of HBV in JMJD5-knockout cells. Taken together, our data suggest that interaction of JMJD5 with HBx facilitates HBV replication through the hydroxylase activity of JMJD5.
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29
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Yan J, Yao Z, Hu K, Zhong Y, Li M, Xiong Z, Deng M. Hepatitis B Virus Core Promoter A1762T/G1764A (TA)/T1753A/T1768A Mutations Contribute to Hepatocarcinogenesis by Deregulating Skp2 and P53. Dig Dis Sci 2015; 60:1315-24. [PMID: 25567052 DOI: 10.1007/s10620-014-3492-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 12/11/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM Hepatitis B virus core promoter (CP) mutations can increase risk of hepatocellular carcinoma. The CP region overlaps with the HBV X (HBx) gene, which has been associated with hepatocarcinogenesis. The cyclin kinase inhibitor P53 is an important regulator of cell cycle progression. We determined whether HBx mutants that result from mutations in the CP deregulate P53. METHODS A HBx combination (combo) mutant with changes in the CP region that corresponded to A1762T/G1764A (TA), T1753A, and T1768A was constructed and expressed in L-02 and Hep3B cells. The effects of CP mutations on expression and degradation of P53, and the effects on cell cycle progression and proliferation were analyzed. RESULTS The combo mutant decreased levels of P53 and increased cyclin D1 expression, accelerated P53 degradation in L-02 cells, accelerated cell cycle progression, and increased expression of S-phase kinase-associated protein 2 (Skp2) in L-02 and Hep3B cells. Silencing of Skp2 abrogated the effects of CP mutations on P53 expression. The kinetics of P53 expression correlated with changes in cell cycle distribution. CONCLUSIONS The HBx mutant with a combination of CP mutations can up-regulate Skp2, which then down-regulates P53 via ubiquitin-mediated proteasomal degradation, increasing the risk of hepatocellular carcinoma.
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Affiliation(s)
- Jian Yan
- Hepatobiliary Surgery Department, The Third Affiliated Hospital of Sun Yat-Sen University, No. 600, TianHe Road, TianHe District, Guangzhou City, 510630, China
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30
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Shahnazari P, Sayehmiri K, Minuchehr Z, Parhizkar A, Poustchi H, Montazeri G, Mohamadkhani A. The Increased Level of Serum p53 in Hepatitis B-Associated Liver Cirrhosis. IRANIAN JOURNAL OF MEDICAL SCIENCES 2014; 39:446-51. [PMID: 25242843 PMCID: PMC4164892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/16/2012] [Accepted: 05/12/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND The ability of tumour suppressor protein p53 (P53) to regulate cell cycle processes can be modulated by hepatitis B virus (HBV). While preliminary evidences indicates the involvement of protein-x of HBV (HBx) in altering p53 DNA binding, no further data have been accumulated for the significance of serum p53 in chronic hepatitis B virus infected patients. METHODS 72 non-cirrhotic and 19 cirrhotic patients infected by HBV were enrolled for the analysis in this study. Enzyme linked immunosorbent assay (ELISA) was performed to study the concentrations of serum p53 protein. The tertiary structures of HBx and P53 were docked by Z-dock and Hex servers for in-silico protein-protein interaction analysis. RESULTS There was a significant association between the serum p53 and cirrhosis (OR=1.81 95% CI: 1.017-3.2, P=0.044). Cirrhotic patients had higher level of serum p53 compare with chronic infection of HBV (1.98±1.22 vs. 1.29±0.72 U/ml, P=0.05). No evidence of correlation was seen between the different variables such as age, gender, log viral load, serum alkaline phosphatase (ALP) and alanine aminotransferase (ALT) with serum p53. Tertiary model shows that the amino acid residues from Arg110 to Lys132 of the N-terminal of P53 which is critical for ubiquitination, are bonded to a region in N- terminal of HBx amino acid residues from Arg19 to Ser33. CONCLUSION There is an increase in serum p53 in HBV-related cirrhosis patients. In this case, HBx might be responsible for such higher concentration of p53 through HBx-p53 protein-protein interaction, as is shown by molecular modeling approach.
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Affiliation(s)
- Parisa Shahnazari
- Monoclonal Antibody Research Centre, Avicenna Research Institute, ACECR, Tehran, Iran;
| | - Kourosh Sayehmiri
- Psychosocial Injuries Research Centre, Ilam University of Medical sciences, Ilam, Iran;
| | - Zarrin Minuchehr
- National Institute of Genetic Engineering and Biotechnology, NIGEB, Tehran, Iran;
| | - Ardavan Parhizkar
- Digestive Disease Research Centre, Shariati Hospital, Tehran University of Medical Science, Tehran, Iran
| | - Hossein Poustchi
- Digestive Disease Research Centre, Shariati Hospital, Tehran University of Medical Science, Tehran, Iran
| | - Ghodratollah Montazeri
- Digestive Disease Research Centre, Shariati Hospital, Tehran University of Medical Science, Tehran, Iran
| | - Ashraf Mohamadkhani
- Digestive Disease Research Centre, Shariati Hospital, Tehran University of Medical Science, Tehran, Iran
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31
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Chang KC, Chang Y, Wang LHC, Tsai HW, Huang W, Su IJ. Pathogenesis of virus-associated human cancers: Epstein–Barr virus and hepatitis B virus as two examples. J Formos Med Assoc 2014; 113:581-90. [DOI: 10.1016/j.jfma.2013.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 08/02/2013] [Accepted: 09/02/2013] [Indexed: 12/12/2022] Open
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32
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Lee JJ, Kim PTW, Fischer S, Fung S, Gallinger S, McGilvray I, Moulton CA, Wei AC, Greig PD, Cleary SP. Impact of Viral Hepatitis on Outcomes after Liver Resection for Hepatocellular Carcinoma: Results from a North American Center. Ann Surg Oncol 2014; 21:2708-16. [DOI: 10.1245/s10434-014-3609-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Indexed: 12/19/2022]
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33
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Involvement of DNA damage response pathways in hepatocellular carcinoma. BIOMED RESEARCH INTERNATIONAL 2014; 2014:153867. [PMID: 24877058 PMCID: PMC4022277 DOI: 10.1155/2014/153867] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/23/2014] [Accepted: 03/25/2014] [Indexed: 12/16/2022]
Abstract
Hepatocellular carcinoma (HCC) has been known as one of the most lethal human malignancies, due to the difficulty of early detection, chemoresistance, and radioresistance, and is characterized by active angiogenesis and metastasis, which account for rapid recurrence and poor survival. Its development has been closely associated with multiple risk factors, including hepatitis B and C virus infection, alcohol consumption, obesity, and diet contamination. Genetic alterations and genomic instability, probably resulted from unrepaired DNA lesions, are increasingly recognized as a common feature of human HCC. Dysregulation of DNA damage repair and signaling to cell cycle checkpoints, known as the DNA damage response (DDR), is associated with a predisposition to cancer and affects responses to DNA-damaging anticancer therapy. It has been demonstrated that various HCC-associated risk factors are able to promote DNA damages, formation of DNA adducts, and chromosomal aberrations. Hence, alterations in the DDR pathways may accumulate these lesions to trigger hepatocarcinogenesis and also to facilitate advanced HCC progression. This review collects some of the most known information about the link between HCC-associated risk factors and DDR pathways in HCC. Hopefully, the review will remind the researchers and clinicians of further characterizing and validating the roles of these DDR pathways in HCC.
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Shlomai A, de Jong YP, Rice CM. Virus associated malignancies: the role of viral hepatitis in hepatocellular carcinoma. Semin Cancer Biol 2014; 26:78-88. [PMID: 24457013 DOI: 10.1016/j.semcancer.2014.01.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/29/2013] [Accepted: 01/09/2014] [Indexed: 02/06/2023]
Abstract
Hepatocellular carcinoma (HCC) is the third leading fatal cancer worldwide and its incidence continues to increase. Chronic viral hepatitis involving either hepatitis B virus (HBV) or hepatitis C virus (HCV) infection is the leading etiology for HCC, making HCC prevention a major goal of antiviral therapy. While recent clinical observations and translational research have enhanced our understanding of the molecular mechanisms driving the initiation and progression of HCC, much remains unknown. Current data indicates that HCC tumors are highly complex and heterogeneous resulting from the aberrant function of multiple molecular pathways. This complex biology is responsible, at least in part, for the absence of highly efficient target-directed therapies for this deadly cancer. Additionally, the direct or indirect effect of HBV and HCV infection on the development of HCC is still a contentious issue. Thus, the question remains whether viral hepatitis-associated HCC stems from virus-specific factors, and/or from a general mechanism involving inflammation and tissue regeneration. In this review we summarize general mechanisms implicated in HCC, emphasizing data generated by new technologies available today. We also highlight specific pathways by which HBV and HCV could be involved in HCC pathogenesis. However, improvements to current in vitro and in vivo systems for both viruses will be needed to rigorously define the temporal sequence and specific pathway dysregulations that drive the strong clinical link between chronic hepatitis virus infection and HCC.
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Affiliation(s)
- Amir Shlomai
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA.
| | - Ype P de Jong
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA; Division of Gastroenterology and Hepatology, Center for the Study of Hepatitis C, Weill Cornell Medical College, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA.
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Kordestani R, Mirshafiee H, Hosseini SM, Sharifi Z. Effect of Hepatitis B Virus X Gene on the Expression Level of p53 Gene using Hep G2 Cell Line. Avicenna J Med Biotechnol 2014; 6:3-9. [PMID: 24523952 PMCID: PMC3895577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND The HBV-X (HBX) protein is believed to contribute to the development of HCC. However, the molecular mechanisms involved in HBX- mediated hepatocarcinogenesis remain obscure. In this study, the effect of hepatitis B virus X gene and its protein product HBxAg on expression of p53 gene in Hep G2 cell line was investigated. METHODS Viral DNA extracted from HBV-positive serum and HBX gene region was amplified using polymerase chain reaction (PCR). Then, PCR product was cloned into the pcDNA3 vector. After confirmation of cloning, the recombinant plasmid pcDNA3-X was transfected into HepG2 cell line using lipid-mediated DNA-transfection procedure. SDS-PAGE and western blotting methods were used to identify expression of HBX protein. Relative quantification was used to analyze the p53gene expression using the 2-(ΔΔ Ct) method. RESULTS Recombinant plasmid pcDNA3-HBX was confirmed by restriction endonucleases digestion and colony-PCR. The results of SDS-PAGE and western blot assays showed that HBX gene could be expressed in Hep G2 cell line. There was no significant difference between the expression levels of p53 compared with GAPDH gene as housekeeping gene (p < 0.05). CONCLUSION There was no significant difference in the protein levels between the transfected cells with X gene containing HBX130 and HBX131 double mu-tations and p53 gene. It is necessary to do more studies on Hepatitis B virus to understand the role of HBX on the development of liver cancer and its function on p53 tumor suppressor protein.
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Affiliation(s)
- Roghyeh Kordestani
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran,Department of Microbiology, School of Biological Science, Shahid Beheshti University, Tehran, Iran
| | - Hamideh Mirshafiee
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran,Department of Microbiology, School of Biological Science, Shahid Beheshti University, Tehran, Iran
| | - Seyed Masoud Hosseini
- Department of Microbiology, School of Biological Science, Shahid Beheshti University, Tehran, Iran
| | - Zohreh Sharifi
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran,Corresponding author: Zohreh Sharifi, Ph.D., Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran. Tel: +98 21 88601501-30, Fax: +98 21 88601555. E-mail:
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Xie N, Chen X, Zhang T, Liu B, Huang C. Using proteomics to identify the HBx interactome in hepatitis B virus: how can this inform the clinic? Expert Rev Proteomics 2013; 11:59-74. [PMID: 24308553 DOI: 10.1586/14789450.2014.861745] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hepatitis B virus (HBV) is a small and enveloped DNA virus, of which chronic infection is the main risk factor of liver cirrhosis and hepatocellular carcinoma. Hepatitis B virus X protein (HBx) is a multifunctional protein encoded by HBV genome, which have significant effects on HBV replication and pathogenesis. Through directly interacting with cellular proteins, HBx is capable to promote HBV replication, regulate transcription of host genes, disrupt protein degradation, modulate signaling pathway, manipulate cell death and deregulate cell cycle. In this review, we briefly discuss the diversified effects of HBx-interactome and their potential clinical significances.
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Affiliation(s)
- Na Xie
- The State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, P.R. China
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38
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Leenders GB, Tuszynski JA. Stochastic and Deterministic Models of Cellular p53 Regulation. Front Oncol 2013; 3:64. [PMID: 23565502 PMCID: PMC3613726 DOI: 10.3389/fonc.2013.00064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 03/08/2013] [Indexed: 01/15/2023] Open
Abstract
The protein p53 is a key regulator of cellular response to a wide variety of stressors. In cancer cells inhibitory regulators of p53 such as MDM2 and MDMX proteins are often overexpressed. We apply in silico techniques to better understand the role and interactions of these proteins in a cell cycle process. Furthermore we investigate the role of stochasticity in determining system behavior. We have found that stochasticity is able to affect system behavior profoundly. We also derive a general result for the way in which initially synchronized oscillating stochastic systems will fall out of synchronization with each other.
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Kapoor NR, Ahuja R, Shukla SK, Kumar V. The HBx protein of hepatitis B virus confers resistance against nucleolar stress and anti-cancer drug-induced p53 expression. FEBS Lett 2013; 587:1287-92. [PMID: 23507139 DOI: 10.1016/j.febslet.2013.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/28/2013] [Accepted: 03/03/2013] [Indexed: 12/28/2022]
Abstract
The nucleolus is a stress sensor associated with cell cycle progression and a viral target. However, the role of the nucleolus during hepatitis B virus infection has not been studied. Here we show that under nucleolar stress, the HBx oncoprotein down-regulates p53 and p21(waf1) levels by disrupting the interaction between ribosomal protein L11 and MDM2. Further, HBx inhibited Act D-mediated down-regulation of proliferative factors such as c-Myc and cyclin E and revived RNA pol I-dependent transcription under these conditions. Importantly, HBx also countered the action of anticancer drug Paclitaxel suggesting its possible role in drug resistance. Thus, HBx not only can facilitate cell proliferation under stress conditions but can confer resistance against anticancer drugs.
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Affiliation(s)
- Neetu Rohit Kapoor
- Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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40
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Altered binding site selection of p53 transcription cassettes by hepatitis B virus X protein. Mol Cell Biol 2012; 33:485-97. [PMID: 23149944 DOI: 10.1128/mcb.01189-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The key cellular regulator p53 is a common target of viral oncoproteins. However, the mechanism by which p53 transcription regulation is modulated by hepatitis B virus X protein (HBx), a transcription cofactor implicated in hepatitis B virus-associated hepatocellular carcinoma (HCC), is poorly understood. By integrating p53 chromatin immunoprecipitation (ChIP)-on-chip and expression profiling of an HBx-expressing cell culture system, we report that HBx alters p53 binding site selectivity in the regulatory regions of genes, and this is associated with their aberrant expression. Using an HBx-deregulated gene, p53AIP1, as a model, we show that HBx aberrantly increases p53AIP1 expression by conferring p53 selectivity for a more conserved binding site in its regulatory region. We further demonstrate that HBx-deregulated increased p53AIP1 expression is relevant in HCC livers and define a functional role for p53AIP1 in mediating HBx-induced apoptosis in vitro. Significantly, we provide evidence that specific p53-associated transcription cofactors and coregulators are differentially recruited in the presence of HBx, effecting a PCAF-mediated "p53 Lys320 acetylation switch" that results in altered binding site selection of distinct p53 transcription cassettes. The findings here clarify the role of HBx in modulating p53 transcription regulation and provide a novel mechanistic insight into this deregulation.
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Pro-apoptotic or anti-apoptotic property of X protein of hepatitis B virus is determined by phosphorylation at Ser31 by Akt. Arch Biochem Biophys 2012; 528:156-62. [PMID: 22982405 DOI: 10.1016/j.abb.2012.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/14/2012] [Accepted: 08/16/2012] [Indexed: 01/16/2023]
Abstract
The X protein of hepatitis B virus (HBx) has been specifically implicated in either pro-apoptotic or anti-apoptotic activity in an experimental system, but the underlying mechanism is yet uncertain. Activations of survival and proliferation signaling pathways appear to account partly for its anti-apoptotic property. Change in mitochondrial membrane potential may be responsible for its apoptotic property. In this study, we isolated two HBx isoforms from an HBV carrier, one of which contains Akt phosphorylation site at Ser31 and functions as an anti-apoptotic protein (designated HBx-S31). The other does not contain Akt phosphorylation site and functions as an apoptotic protein (designated HBx-L31). HBx-S31 can activate Akt, whereas HBx-L31 cannot; the former enhances tumor growth, whereas the latter suppresses tumorigenesis. Our study provides evidence that HBx plays dual roles, namely pro-apoptotic and anti-apoptotic, through different isoforms in which HBx with Ser31 transduces survival signal.
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Lee SH, Cha EJ, Lim JE, Kwon SH, Kim DH, Cho H, Han KH. Structural characterization of an intrinsically unfolded mini-HBX protein from hepatitis B virus. Mol Cells 2012; 34:165-9. [PMID: 22820921 PMCID: PMC3887815 DOI: 10.1007/s10059-012-0060-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 12/19/2022] Open
Abstract
The hepatitis B virus x protein (HBX) is expressed in HBV-infected liver cells and can interact with a wide range of cellular proteins. In order to understand such promiscuous behavior of HBX we expressed a truncated mini-HBX protein (named Tr-HBX) (residues 18-142) with 5 Cys → Ser mutations and characterized its structural features using circular dichroism (CD) spectropolarimetry, NMR spectroscopy as well as bioinformatics tools for predicting disorder in intrinsically unstructured proteins (IUPs). The secondary structural content of Tr-HBX from CD data suggests that Tr-HBX is only partially folded. The protein disorder prediction by IUPred reveals that the unstructured region encompasses its N-terminal ~30 residues of Tr-HBX. A two-dimensional (1)H-(15)N HSQC NMR spectrum exhibits fewer number of resonances than expected, suggesting that Tr-HBX is a hybrid type IUP where its folded C-terminal half coexists with a disordered N-terminal region. Many IUPs are known to be capable of having promiscuous interactions with a multitude of target proteins. Therefore the intrinsically disordered nature of Tr-HBX revealed in this study provides a partial structural basis for the promiscuous structure-function behavior of HBX.
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Affiliation(s)
- Si-Hyung Lee
- Biomedical Translational Research Center, Division of Convergent Biomedical Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
| | - Eun-Ji Cha
- Biomedical Translational Research Center, Division of Convergent Biomedical Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
| | - Ji-Eun Lim
- Biomedical Translational Research Center, Division of Convergent Biomedical Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
| | - Soon-Hwan Kwon
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721,
Korea
| | - Do-Hyoung Kim
- Biomedical Translational Research Center, Division of Convergent Biomedical Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
| | - Hyeseong Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721,
Korea
| | - Kyou-Hoon Han
- Biomedical Translational Research Center, Division of Convergent Biomedical Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
- Department of Bioinformatics, University of Science and Technology, Daejeon 305-333,
Korea
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Abstract
Agents commonly used in cancer chemotherapy rely on the induction of cell death via apoptosis, mitotic catastrophe, premature senescence and autophagy. Chemoresistance is the major factor limiting long-term treatment success in patients with hepatocellular carcinoma (HCC). Recent studies have revealed that the hepatitis B virus X protein (HBx) exerts anti-apoptotic effects, resulting in an increased drug resistance in HCC cells. In this study, we showed that etoposide treatment activated caspase-8 and caspase-3, leading to cleavages of p53, Bid and PARP, which subsequently induced apoptosis. Furthermore, p53 and Bid were accumulated in cytoplasm following etoposide treatment. However, HBx significantly attenuated etoposide-induced cell death. In HBx-expressing cells, despite the translocation of p53 and Bid to cytoplasm, the activation of caspases was inhibited. Furthermore, the phosphorylation of extracellular-signal-regulated kinase (ERK) was markedly increased in HBx-expressing cells. Moreover, the pretreatment with trichostatin A (TSA, a histone deacetylase inhibitor) or TSA in combination with etoposide significantly sensitized HCC cells to apoptosis by inhibiting ERK phosphorylation, reactivating caspases and PARP, and inducing translocation of p53 and Bid to cytoplasm. Collectively, HBx reduces the sensitivity of HCC cells to chemotherapy. TSA in combination with etoposide can significantly overcome the increased resistance of HBx-expressing HCC cells to chemotherapy.
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Basu A, Leong SSJ. Development of an enzyme-linked immunosorbent assay analytical platform for refolding yield determination of recombinant hepatitis B virus X (HBx) protein. Anal Biochem 2011; 418:155-7. [DOI: 10.1016/j.ab.2011.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 07/11/2011] [Accepted: 07/13/2011] [Indexed: 10/17/2022]
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A rational design for hepatitis B virus X protein refolding and bioprocess development guided by second virial coefficient studies. Appl Microbiol Biotechnol 2011; 90:181-91. [DOI: 10.1007/s00253-010-3058-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 11/28/2010] [Accepted: 12/03/2010] [Indexed: 10/18/2022]
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46
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Kim KH. [Pro-apoptotic function of hepatitis B virus X protein]. THE KOREAN JOURNAL OF HEPATOLOGY 2010; 16:112-22. [PMID: 20606495 DOI: 10.3350/kjhep.2010.16.2.112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Infection of hepatitis B virus (HBV) is a main cause of liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). Among the HBV-encoded proteins, the HBV X protein (HBx) has been suspected to be strongly involved in HBV-associated liver pathogenesis. HBx, a virally encoded multifunctional regulator, has been shown to induce apoptosis, anti-apoptosis, proliferation, and transformation of cells depending on the cell lines, model systems used, assay protocols, and research groups. Among the several activities of HBx, the pro-apoptotic function of HBx will be discussed in this review. Given that the disruption of apoptosis pathway by HBx contributes to the liver pathogenesis, a better understanding of the molecular interference in the cellular pro-apoptotic networks by HBx will provide useful clues for the intervention in HBV-mediated liver diseases.
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Affiliation(s)
- Kyun-Hwan Kim
- Department of Pharmacology, School of Medicine and Center for Cancer Research and Diagnostic Medicine, IBST, Konkuk University, Seoul, Korea.
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Abstract
Hepatitis B virus is one of the most important etiologic factors of hepatocellular carcinoma. The present review discusses the molecular mechanisms of virus-induced carcinogenesis, indirect and direct effects of the infection. The cell damage-evoked regeneration and proliferation, as well as the viral proteins that induce chromosomal, genetic and epigenetic changes, play a key role in the multistep process leading to malignant cell transformation. Integration of HBV DNA in to the host DNA, activation of oncogenes and inactivation of tumor suppressor genes are of basic significance. The hepatitis B virus related complications such as cirrhosis and hepatocellular carcinoma can be prevented by vaccination or eradication of the virus with antiviral therapy.
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Affiliation(s)
- Alajos Pár
- Pécsi Tudományegyetem, Altalános Orvostudományi Kar, Klinikai Központ I. Belgyógyászati Klinika Pécs Ifjúság u. 13. 7624.
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48
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p53 Promotes proteasome-dependent degradation of oncogenic protein HBx by transcription of MDM2. Mol Biol Rep 2009; 37:2935-40. [PMID: 19842060 DOI: 10.1007/s11033-009-9855-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 09/28/2009] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus X protein (HBx) is closely involved in the development of hepatocellular carcinoma (HCC). Tumor suppressor p53 was reported to induce HBx degradation and repress its oncogenic function recently, but the molecular mechanism is unknown. In this study, we attempted to identify the underlying mechanism. We found that overexpression of p53 protein reduces the level of HBx protein and shortens its half-life, however, in MDM2 knock out cells, p53 has no effects on degradation of HBx, meanwhile, overexpression of MDM2 in absence of p53 can accelerate turnover of HBx protein. These indicate that p53-mediated HBx degradation is MDM2-dependent. MDM2 interacts with HBx in vitro and in vivo but does not promote its ubiquitination. In consistent with the results above, HCC tissue samples with wild-type p53 hardly detect HBx protein, whereas, HBx always accumulate in the tissues with mutant p53. Our data provide a possible mechanism on how p53 regulate HBx stability and also a new clue for the study of p53 mutation and HCC development.
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Kim YJ, Jung JK, Lee SY, Jang KL. Hepatitis B virus X protein overcomes stress-induced premature senescence by repressing p16(INK4a) expression via DNA methylation. Cancer Lett 2009; 288:226-35. [PMID: 19656618 DOI: 10.1016/j.canlet.2009.07.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 06/30/2009] [Accepted: 07/10/2009] [Indexed: 12/12/2022]
Abstract
Cellular senescence is an important tumor suppression process under diverse oncogenic conditions, entering a state of irreversible growth arrest to prevent damaged cells from undergoing aberrant proliferation. Developing a means of evading senescence thus seems to be a fundamental task that all cancer cells should solve early on. Here, we show that an oncogenic X protein of hepatitis B virus (HBx) overcomes cellular senescence provoked by a universal premature senescence inducer, H(2)O(2), in human hepatoma cells, as demonstrated by impaired induction of senescence-associated biomarkers, including morphological change, G(1) arrest, and beta-galactosidase activity, in the presence of HBx. HBx induced DNA hypermethylation of p16(INK4a) promoter and subsequently interfered action of transcription factors like Ets1 and Ets2 activated by H(2)O(2) through the p38(MAPK) pathway, resulting in inhibition of its transcription. Down-regulation of p16(INK4a) expression by HBx subsequently led to activation of G(1)-CDKs, phosphorylation of Rb, activation of E2F1, and finally evasion from G(1) arrest induced by H(2)O(2). Levels of another senescence regulator, p21(waf1), however, were not affected by HBx under our senescence-inducing conditions. In addition, the potentials of HBx to inactivate Rb and subsequently inhibit cellular senescence almost completely disappeared when levels of p16(INK4a) were recovered either by exogenous complementation or inhibition of the promoter hypermethylation. To our knowledge, our present study represents the first report that an oncogenic virus evades cellular senescence through epigenetic down-regulation of p16(INK4a) expression.
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Affiliation(s)
- Ye-Jin Kim
- Department of Microbiology, Pusan National University, Busan, Republic of Korea
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Qu J, Lin J, Zhang S, Zhu Z, Ni C, Zhang S, Gao H, Zhu M. HBV DNA can bind to P53 protein and influence p53 transactivation in hepatoma cells. Biochem Biophys Res Commun 2009; 386:504-9. [DOI: 10.1016/j.bbrc.2009.06.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 06/15/2009] [Indexed: 11/28/2022]
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