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Van Damme E, Vanhove J, Severyn B, Verschueren L, Pauwels F. The Hepatitis B Virus Interactome: A Comprehensive Overview. Front Microbiol 2021; 12:724877. [PMID: 34603251 PMCID: PMC8482013 DOI: 10.3389/fmicb.2021.724877] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/17/2021] [Indexed: 12/19/2022] Open
Abstract
Despite the availability of a prophylactic vaccine, chronic hepatitis B (CHB) caused by the hepatitis B virus (HBV) is a major health problem affecting an estimated 292 million people globally. Current therapeutic goals are to achieve functional cure characterized by HBsAg seroclearance and the absence of HBV-DNA after treatment cessation. However, at present, functional cure is thought to be complicated due to the presence of covalently closed circular DNA (cccDNA) and integrated HBV-DNA. Even if the episomal cccDNA is silenced or eliminated, it remains unclear how important the high level of HBsAg that is expressed from integrated HBV DNA is for the pathology. To identify therapies that could bring about high rates of functional cure, in-depth knowledge of the virus' biology is imperative to pinpoint mechanisms for novel therapeutic targets. The viral proteins and the episomal cccDNA are considered integral for the control and maintenance of the HBV life cycle and through direct interaction with the host proteome they help create the most optimal environment for the virus whilst avoiding immune detection. New HBV-host protein interactions are continuously being identified. Unfortunately, a compendium of the most recent information is lacking and an interactome is unavailable. This article provides a comprehensive review of the virus-host relationship from viral entry to release, as well as an interactome of cccDNA, HBc, and HBx.
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Affiliation(s)
- Ellen Van Damme
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
| | - Jolien Vanhove
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium.,Early Discovery Biology, Charles River Laboratories, Beerse, Belgium
| | - Bryan Severyn
- Janssen Research & Development, Janssen Pharmaceutical Companies, Springhouse, PA, United States
| | - Lore Verschueren
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
| | - Frederik Pauwels
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
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2
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Inhibitory effect of a novel thiazolidinedione derivative on hepatitis B virus entry. Antiviral Res 2021; 194:105165. [PMID: 34419484 DOI: 10.1016/j.antiviral.2021.105165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022]
Abstract
The development of novel antivirals to treat hepatitis B virus (HBV) infection is still needed because currently available drugs do not completely eradicate chronic HBV in some patients. Recently, troglitazone and ciglitazone, classified among the compounds including the thiazolidinedione (TZD) moiety, were found to inhibit HBV infection, but these compounds are not clinically available. In this study, we synthesized 11 TZD derivatives, compounds 1-11, and examined the effect of each compound on HBV infection in HepG2 cells expressing NTCP (HepG2/NTCP cells). Among the derivatives, (Z)-5-((4'-(naphthalen-1-yl)-[1,1'-biphenyl]-4-yl)methylene)thiazolidine-2,4-dione (compound 6) showed the highest antiviral activity, with an IC50 value of 0.3 μM and a selectivity index (SI) of 85, but compound 6 did not affect HCV infection. Treatment with compound 6 inhibited HBV infection in primary human hepatocytes (PHHs) but did not inhibit viral replication in HepG2.2.15 cells or HBV DNA-transfected Huh7 cells. Moreover, treatment with compound 6 significantly impaired hepatitis delta virus (HDV) infection and inhibited a step in HBV particle internalization but did not inhibit attachment of the preS1 lipopeptide or viral particles to the cell surface. These findings suggest that compound 6 interferes with HBV infection via inhibition of the internalization process.
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Hwang JS, Lee WJ, Hur J, Lee HG, Kim E, Lee GH, Choi MJ, Lim DS, Paek KS, Seo HG. Rosiglitazone-dependent dissociation of HuR from PPAR-γ regulates adiponectin expression at the posttranscriptional level. FASEB J 2019; 33:7707-7720. [PMID: 30897345 DOI: 10.1096/fj.201802643r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Peroxisome proliferator-activated receptor (PPAR)-γ has been implicated as a key player in the regulation of adiponectin levels via both transcriptional and posttranscriptional mechanisms. Herein, we show that PPAR-γ interacts with human antigen R (HuR) and that the PPAR-γ-HuR complex dissociates following activation of PPAR-γ by rosiglitazone, a specific ligand of PPAR-γ. This rosiglitazone-dependent dissociation of HuR from PPAR-γ leads to nucleocytoplasmic shuttling of HuR and its binding to the 3'-UTR of adiponectin mRNA. PPAR-γ with H321A and H447A double mutation (PPAR-γH321/447A), a mutant lacking ligand-binding activity, impaired HuR dissociation from the PPAR-γ-HuR complex, resulting in reduced nucleocytoplasmic shuttling, even in the presence of rosiglitazone. Consequently, rosiglitazone up-regulated adiponectin levels by modulating the stability of adiponectin mRNA, whereas these effects were abolished by HuR ablation or blocked in cells expressing the PPAR-γH321/447A mutant, indicating that the interaction of PPAR-γ and HuR is a critical event during adiponectin expression. Taken together, the findings demonstrate a novel mechanism for regulating adiponectin expression at the posttranscriptional level and suggest that ligand-mediated activation of PPAR-γ to interfere with interaction of HuR could offer a therapeutic strategy for inflammation-associated diseases that involve decreased adiponectin mRNA stability.-Hwang, J. S., Lee, W. J., Hur, J., Lee, H. G., Kim, E., Lee, G. H., Choi, M.-J., Lim, D.-S., Paek, K. S., Seo, H. G. Rosiglitazone-dependent dissociation of HuR from PPAR-γ regulates adiponectin expression at the posttranscriptional level.
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Affiliation(s)
- Jung Seok Hwang
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Won Jin Lee
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Jinwoo Hur
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Hyuk Gyoon Lee
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Eunsu Kim
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Gyeong Hee Lee
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Mi-Jung Choi
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
| | - Dae-Seog Lim
- Department of Biotechnology, CHA University, Seongnam, Korea
| | | | - Han Geuk Seo
- Sanghuh College of Life Sciences, Konkuk University, Seoul, Korea
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Niu Y, Xu M, Slagle BL, Huang H, Li S, Guo GL, Shi G, Qin W, Xie W. Farnesoid X receptor ablation sensitizes mice to hepatitis b virus X protein-induced hepatocarcinogenesis. Hepatology 2017; 65:893-906. [PMID: 28102638 PMCID: PMC5319891 DOI: 10.1002/hep.28924] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/17/2016] [Indexed: 02/05/2023]
Abstract
UNLABELLED Chronic hepatitis B virus infection is a major risk factor for hepatocellular carcinoma (HCC). Hepatitis B virus X protein (HBx) is a hepatitis B virus protein that has multiple cellular functions, but its role in HCC pathogenesis has been controversial. Farnesoid X receptor (FXR) is a nuclear receptor with activities in anti-inflammation and inhibition of hepatocarcinogenesis. However, whether or how FXR can impact hepatitis B virus/HBx-induced hepatocarcinogenesis remains unclear. In this study, we showed that HBx can interact with FXR and function as a coactivator of FXR. Expression of HBx in vivo enhanced FXR-responsive gene regulation. HBx also increased the transcriptional activity of FXR in a luciferase reporter gene assay. The HBx-FXR interaction was confirmed by coimmunoprecipitation and glutathione S-transferase pull-down assays, and the FXR activation function 1 domain was mapped to bind to the third α helix in the C terminus of HBx. We also found that the C-terminally truncated variants of HBx, which were found in clinical HCC, were not effective at transactivating FXR. Interestingly, recruitment of the full-length HBx, but not the C-terminally truncated HBx, enhanced the binding of FXR to its response element. In vivo, FXR ablation markedly sensitized mice to HBx-induced hepatocarcinogenesis. CONCLUSIONS We propose that transactivation of FXR by full-length HBx may represent a protective mechanism to inhibit HCC and that this inhibition may be compromised upon the appearance of C-terminally truncated HBx or when the expression and/or activity of FXR is decreased. (Hepatology 2017;65:893-906).
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Affiliation(s)
- Yongdong Niu
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine, 200032, Shanghai, China
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, Guangdong, China
| | - Meishu Xu
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Betty L. Slagle
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haihua Huang
- Department of Pathology, Second Affiliated Hospital of Shantou University Medical College, 515021, Guangdong, China
| | - Song Li
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Grace L. Guo
- Department of Pharmacology and Toxicology, School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
| | - Ganggang Shi
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, Guangdong, China
| | - Wenxin Qin
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine, 200032, Shanghai, China
| | - Wen Xie
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Corresponding Authors: Dr. Wen Xie, University of Pittsburgh, Pittsburgh, PA 15261, USA. ; or Dr. Wenxin Qin, Shanghai Cancer Institute, Shanghai, China.
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Abstract
Liver cancer, primarily hepatocellular carcinoma (HCC), is a major cause of cancer-related death worldwide. HCC is a suitable model of inflammation-induced cancer because more than 90% of HCC cases are caused by liver damage and chronic inflammation. Several inflammatory response pathways, such as NF-κB and JAK/STAT3 signaling pathways, play roles in the crosstalk between inflammation and HCC. MicroRNAs (miRNAs) are evolutionarily conserved, short endogenous, non-coding single-stranded RNAs that are involved in various biological and pathological processes by regulating gene expression and protein translation. Evidence showed that miRNAs play a pivotal role in hepatitis virus infection and serve as promoters or inhibitors of inflammatory response. Aberrant miRNA was observed during liver inflammation and HCC. Many dysregulated miRNAs modulate the initiation and progression of inflammation-induced HCC. This review summarizes the role and functions of miRNAs in inflammation-associated HCC, as well as the designed therapeutics targeting miRNAs to treat liver inflammation and HCC.
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Affiliation(s)
- Lin Huan
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Lin-Hui Liang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Xiang-Huo He
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
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Gao J, Xiong Y, Wang Y, Wang Y, Zheng G, Xu H. Hepatitis B virus X protein activates Notch signaling by its effects on Notch1 and Notch4 in human hepatocellular carcinoma. Int J Oncol 2015; 48:329-37. [PMID: 26530164 DOI: 10.3892/ijo.2015.3221] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/01/2015] [Indexed: 12/17/2022] Open
Abstract
Deregulated expression of Notch receptors and abnormal activity of Notch signaling have been observed in a growing number of malignant tumors, however, the expression and activity of Notch in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) and their relationship with HBV X protein (HBx) are still not fully elucidated. To address this, we examined the overall expression of Notch receptors in HBV-associated HCC tissues, analyzed their relationship with HBx, and further investigated the role of Notch signaling in HBx stable transfected HepG2 cells (HepG2X). The results showed that Notch signaling could be activated by HBx in HepG2 cells. The expression of cytoplasmic Notch1 or nuclear Notch4 was correlated with the expression of HBx in HBV-associated HCC tissues. The expression of cytoplasmic Notch1 or nuclear Notch4 could also be upregulated by HBx in HepG2X cells. The upregulation of Notch1 by HBx was through p38 MAPK pathway. Moreover, HBx was found to directly interact with Notch1, whereas, not with Notch4 in HepG2X cells. Suppression of Notch signaling by γ-secretase inhibitor (GSI) decreased cell growth, blocked cell cycle progression and induced cell apoptosis in HepG2X cells. The present study indicates that HBx activates Notch signaling by its effects on Notch1 and Notch4, and therefore, recruits Notch signaling as a downstream pathway contributing to its carcinogenic role in HBV-associated HCC.
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Affiliation(s)
- Juan Gao
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
| | - Yimin Xiong
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
| | - Yan Wang
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
| | - Yiming Wang
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
| | - Guorong Zheng
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
| | - Hualin Xu
- Department of Digestive Diseases, Wuhan General Hospital of Guangzhou Command PLA, Wuhan, Hubei 430070, P.R. China
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Downregulation of mPGES-1 Expression via EGR1 Plays an Important Role in Inhibition of Caffeine on PGE2 Synthesis of HBx(+) Hepatocytes. Mediators Inflamm 2015; 2015:372750. [PMID: 26538827 PMCID: PMC4619973 DOI: 10.1155/2015/372750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 02/05/2023] Open
Abstract
We investigated the mechanism of caffeine in influencing HBx(+) hepatocytes to synthesize PGE2. The inhibitory effect of caffeine on hepatocyte proliferation increased with increasing caffeine concentrations (200–800 μM) and treatment times (1–7 days), which was first observed at the second test time point (caffeine treatment for 4 days). The inhibition of caffeine on the growth of HL7702-HBx and HepG2-HBx cells was most obvious at 800 μM caffeine and at caffeine treatment for 7 days. The PGE2 secretion and the expression of mPGES-1 and EGR1 were downregulated, whereas PPARγ expression was upregulated. The mPGES-1 promoter activity of HBx(+) hepatocytes decreased more significantly than that of HBx(−) hepatocytes. Moreover, the expression of EGR1 and PPARγ changed more significantly in HBx(+) hepatocytes cultured for 12 to 24 hours in the presence of 5 mM caffeine. This limited success may be attributed to caffeine releasing the binding of HBx and PPARγ and furthermore affecting the mPGES-1 expression by EGR1 in HBx(+) hepatocytes. The results indicate that caffeine could effectively reduce PGE2 synthesis in HBx(+) hepatocytes by specifically blocking the PPARγ-EGR1-mPGES-1 pathway, thereby providing a new evidence of molecular biology for the hypothesis that drinking coffee is beneficial to HBV-infected patients.
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8
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Montella M, D'Arena G, Crispo A, Capunzo M, Nocerino F, Grimaldi M, Barbieri A, D'Ursi AM, Tecce MF, Amore A, Galdiero M, Ciliberto G, Giudice A. Role of Sex Hormones in the Development and Progression of Hepatitis B Virus-Associated Hepatocellular Carcinoma. Int J Endocrinol 2015; 2015:854530. [PMID: 26491442 PMCID: PMC4600563 DOI: 10.1155/2015/854530] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 12/25/2022] Open
Abstract
Infection with hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC) in developed countries. Epidemiological reports indicate that the incidence of HBV-related HCC is higher in males and postmenopausal females than other females. Increasing evidence suggests that sex hormones such as androgens and estrogens play an important role in the progression of an HBV infection and in the development of HBV-related HCC. While androgen is supposed to stimulate the androgen signaling pathway and cooperate to the increased transcription and replication of HBV genes, estrogen may play a protecting role against the progression of HBV infections and in the development of HBV-related HCC through decreasing HBV RNA transcription and inflammatory cytokines levels. Additionally, sex hormones can also affect HBV-related hepatocarcinogenesis by inducing epigenetic changes such as the regulation of mRNA levels by microRNAs (miRNAs), DNA methylation, and histone modification in liver tissue. This review describes the molecular mechanisms underlying the gender disparity in HBV-related HCC with the aim of improving the understanding of key factors underneath the sex disparity often observed in HBV infections. Furthermore, the review will propose more effective prevention strategies and treatments of HBV-derived diseases.
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Affiliation(s)
- Maurizio Montella
- Epidemiology Unit, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
- *Maurizio Montella:
| | - Giovanni D'Arena
- Department of Onco-Hematology, IRCCS, Cancer Referral Center of Basilicata, 85028 Rionero in Vulture, Italy
| | - Anna Crispo
- Epidemiology Unit, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | - Mario Capunzo
- Department of Medicine and Surgery, University of Salerno, 84081 Fisciano, Italy
| | - Flavia Nocerino
- Epidemiology Unit, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | - Maria Grimaldi
- Epidemiology Unit, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | - Antonio Barbieri
- Animal Facility, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | - Anna Maria D'Ursi
- Department of Pharmacy, University of Salerno, 84084 Fisciano, Salerno, Italy
| | - Mario Felice Tecce
- Department of Pharmacy, University of Salerno, 84084 Fisciano, Salerno, Italy
| | - Alfonso Amore
- Department of Surgery, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | | | - Gennaro Ciliberto
- National Cancer Institute “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
| | - Aldo Giudice
- Epidemiology Unit, National Cancer Institute of Naples “G. Pascale Foundation”, IRCCS, 80131 Naples, Italy
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Liu C, Chen S, Wang X, Chen Y, Tang N. 15d-PGJ2 decreases PGE2 synthesis in HBx-positive liver cells by interfering EGR1 binding to mPGES-1 promoter. Biochem Pharmacol 2014; 91:337-47. [DOI: 10.1016/j.bcp.2014.07.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 07/27/2014] [Accepted: 07/29/2014] [Indexed: 01/05/2023]
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10
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Chen S, Liu C, Wang X, Li X, Chen Y, Tang N. 15-Deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) promotes apoptosis of HBx-positive liver cells. Chem Biol Interact 2014; 214:26-32. [PMID: 24582817 DOI: 10.1016/j.cbi.2014.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/26/2013] [Accepted: 02/19/2014] [Indexed: 12/22/2022]
Abstract
This study aims to investigate the inflammatory response characteristics of liver cells caused by HBV x protein (HBx) and the unique function of the PGE2 inhibitor on HBx-positive liver cells. Tetrazolium blue colorimetric method, flow cytometry, and Western blot were performed to detect the proliferation, cycle, and apoptosis protein expression of HBx-positive HL7702 liver and control cells. The effect of the PGE2 inhibitor 15-Deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) on the growth of HL7702-HBx was also observed. HBx induces the PGE2 accumulation in HL7702 liver cells and promotes their growth and inhibits their apoptosis. HL7702-HBx and HL7702 cells showed increased apoptosis rate, increased apoptosis-promoting protein expression, and reduced apoptosis-inhibiting protein expression under the effect of 15d-PGJ2, and the changes in HL7702-HBx cells were more significant than in HL7702 cells. HBx expression causes liver cells to be more sensitive to the apoptosis-promoting function of 15d-PGJ2. Therefore, the use of 15d-PGJ2 may be a new method for the prevention or treatment of inflammatory changes to cancer caused by HBV infection in liver cells.
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Affiliation(s)
- Siyan Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Chong Liu
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Xiaoqian Wang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Xiujin Li
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Yanling Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Nanhong Tang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China.
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11
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Song K, Han C, Zhang J, Lu D, Dash S, Feitelson M, Lim K, Wu T. Epigenetic regulation of MicroRNA-122 by peroxisome proliferator activated receptor-gamma and hepatitis b virus X protein in hepatocellular carcinoma cells. Hepatology 2013; 58:1681-92. [PMID: 23703729 PMCID: PMC3773012 DOI: 10.1002/hep.26514] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 03/12/2013] [Accepted: 05/02/2013] [Indexed: 12/14/2022]
Abstract
UNLABELLED MicroRNA-122 (miR-122), a pivotal liver-specific miRNA, has been implicated in several liver diseases including hepatocellular carcinoma (HCC) and hepatitis C and B viral infection. This study aimed to explore epigenetic regulation of miR-122 in human HCC cells and to examine the effect of hepatitis C virus (HCV) and hepatitis B virus (HBV). We performed microRNA microarray analysis and identified miR-122 as the most up-regulated miRNA (6-fold) in human HCC cells treated with 5'aza-2'deoxycytidine (5-Aza-CdR, DNA methylation inhibitor) and 4-phenylbutyric acid (PBA, histone deacetylation inhibitor). Real-time polymerase chain reaction (PCR) analysis verified significant up-regulation of miR-122 by 5'aza and PBA in HCC cells, and to a lesser extent in primary hepatocytes. Peroxisome proliferator activated receptor-gamma (PPARγ) and retinoid X receptor alpha (RXRα) complex was found to be associated with the DR1 and DR2 consensus site in the miR-122 gene promoter which enhanced miR-122 gene transcription. 5-Aza-CdR and PBA treatment increased the association of PPARγ/RXRα, but decreased the association of its corepressors (N-CoR and SMRT), with the miR-122 DR1 and DR2 motifs. The aforementioned DNA-protein complex also contains SUV39H1, an H3K9 histone methyl transferase, which down-regulates miR-122 expression. CONCLUSIONS These findings establish a novel role of the PPARγ binding complex for epigenetic regulation of miR-122 in human HCC cells. Moreover, we show that hepatitis B virus X protein binds PPARγ and inhibits the transcription of miR-122, whereas hepatitis C viral particles exhibited no significant effect; these findings provide mechanistic insight into reduction of miR-122 in patients with HBV but not with HCV infection.
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Affiliation(s)
- Kyoungsub Song
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Chang Han
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Jinqiang Zhang
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Dongdong Lu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
| | - Mark Feitelson
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA 19122
| | - Kyu Lim
- Department of Biochemistry, College of Medicine, Cancer Research Institute and Infection Signaling Network Research Center, Chungnam National University, Daejeon, Korea
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA 70112
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12
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He X, Hu JL, Li J, Zhao L, Zhang Y, Zeng YJ, Dai SS, He FT. A feedback loop in PPARγ-adenosine A2A receptor signaling inhibits inflammation and attenuates lung damages in a mouse model of LPS-induced acute lung injury. Cell Signal 2013; 25:1913-23. [PMID: 23712033 DOI: 10.1016/j.cellsig.2013.05.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/12/2013] [Indexed: 12/13/2022]
Abstract
Although peroxisome proliferator-activated receptor-γ (PPARγ) and adenosine A2A receptor (A2AR) are reported to be anti-inflammatory factors in acute lung injury (ALI), their internal link and synergic or antagonistic effect after activation are poorly understood. Here, we found that PPARγ and A2AR could upregulate the mRNA and protein expressions of each other in lung tissues of LPS-induced mouse ALI model and murine macrophages. Further investigation demonstrated that PPARγ upregulated A2AR expression by directly binding to a DR10 response element (-218 to -197) within A2AR gene promoter region. Instead of directly interacting with PPARγ, A2AR stimulated PPARγ expression via protein kinase A (PKA)-cAMP response element binding protein (CREB) signaling by provoking the binding of CREB to a cAMP responsive element (CRE)-like site in PPARγ gene promoter region. In addition, combination of PPARγ and A2AR agonists was found to exert obviously better effect on suppressing neutrophil infiltration and inflammatory cytokine expressions, attenuating lung edema, pathological changes and improving lung function of blood gas exchange than their single application. These findings reveal a novel functional positive feedback loop between PPARγ and A2AR signaling to potentialize their effect on inhibiting inflammation and attenuating lung damages in ALI. It suggests that targeting this PPARγ-A2AR signaling rather than PPARγ or A2AR alone may be a more attractive and efficient potential therapeutic strategy for ALI.
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Affiliation(s)
- Xie He
- Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing 400038, China
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13
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Peyrou M, Ramadori P, Bourgoin L, Foti M. PPARs in Liver Diseases and Cancer: Epigenetic Regulation by MicroRNAs. PPAR Res 2012; 2012:757803. [PMID: 23024649 PMCID: PMC3449131 DOI: 10.1155/2012/757803] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 06/27/2012] [Indexed: 12/19/2022] Open
Abstract
Peroxisome-proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors that exert in the liver a transcriptional activity regulating a whole spectrum of physiological functions, including cholesterol and bile acid homeostasis, lipid/glucose metabolism, inflammatory responses, regenerative mechanisms, and cell differentiation/proliferation. Dysregulations of the expression, or activity, of specific PPAR isoforms in the liver are therefore believed to represent critical mechanisms contributing to the development of hepatic metabolic diseases, disorders induced by hepatic viral infections, and hepatocellular adenoma and carcinoma. In this regard, specific PPAR agonists have proven to be useful to treat these metabolic diseases, but for cancer therapies, the use of PPAR agonists is still debated. Interestingly, in addition to previously described mechanisms regulating PPARs expression and activity, microRNAs are emerging as new important regulators of PPAR expression and activity in pathophysiological conditions and therefore may represent future therapeutic targets to treat hepatic metabolic disorders and cancers. Here, we reviewed the current knowledge about the general roles of the different PPAR isoforms in common chronic metabolic and infectious liver diseases, as well as in the development of hepatic cancers. Recent works highlighting the regulation of PPARs by microRNAs in both physiological and pathological situations with a focus on the liver are also discussed.
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Affiliation(s)
- Marion Peyrou
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Pierluigi Ramadori
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Lucie Bourgoin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Michelangelo Foti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
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14
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Ewald PW, Swain Ewald HA. Infection, mutation, and cancer evolution. J Mol Med (Berl) 2012; 90:535-41. [PMID: 22476248 DOI: 10.1007/s00109-012-0891-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/03/2012] [Accepted: 03/07/2012] [Indexed: 01/27/2023]
Abstract
An understanding of oncogenesis can be fostered by an integration of mechanistic studies with evolutionary considerations, which help explain why these mechanisms occur. This integration emphasizes infections and mutations as joint essential causes for many cancers. It suggests that infections may play a broader causal role in oncogenesis than has been generally appreciated. An evolutionary perspective also suggests that oncogenic viruses will tend to be transmitted by routes that provide infrequent opportunities for transmission, such as transmission by sexual and salivary contact. Such routes increase the intensity of natural selection for persistence within hosts, and molecular mechanisms for persistence often compromise critical barriers to oncogenesis, particularly cell cycle arrest, apoptosis, and a cap on the total number of divisions that a cell can undergo.
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Affiliation(s)
- Paul W Ewald
- Department of Biology, University of Louisville, Louisville, KY 40292, USA.
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15
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Kim SJ, Choi Y, Choi YH, Park T. Obesity activates toll-like receptor-mediated proinflammatory signaling cascades in the adipose tissue of mice. J Nutr Biochem 2012; 23:113-22. [DOI: 10.1016/j.jnutbio.2010.10.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 10/08/2010] [Accepted: 10/28/2010] [Indexed: 02/06/2023]
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16
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Inhibition of cellular proteasome activities mediates HBX-independent hepatitis B virus replication in vivo. J Virol 2010; 84:9326-31. [PMID: 20592087 DOI: 10.1128/jvi.00579-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The X protein (HBX) of the hepatitis B virus (HBV) is essential for HBV productive infection in vivo. Our previous study (Z. Hu, Z. Zhang, E. Doo, O. Coux, A. L. Goldberg, and T. J. Liang, J. Virol. 73:7231-7240, 1999) shows that interaction of HBX with the proteasome complex may underlie the pleiotropic functions of HBX. Previously, we demonstrated that HBX affects hepadnaviral replication through a proteasome-dependent pathway in cell culture models. In the present study, we studied the effect of the proteasome inhibitor MLN-273 in two HBV mouse models. We demonstrated that administration of MLN-273 to transgenic mice containing the replication-competent HBV genome with the defective HBX gene substantially enhanced HBV replication, while the compound had a minor effect on wild-type HBV transgenic mice. Similar results were obtained by using C57BL/6 mice infected with recombinant adenoviruses expressing the replicating HBV genome. Our data suggest that HBV replication is subjected to regulation by cellular proteasome and HBX functions through the inhibition of proteasome activities to enhance HBV replication in vivo.
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17
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Peroxisome proliferator-activated receptors in HBV-related infection. PPAR Res 2009; 2009:145124. [PMID: 19365584 PMCID: PMC2667936 DOI: 10.1155/2009/145124] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 02/18/2009] [Indexed: 12/18/2022] Open
Abstract
Thirty years after its discovery, the hepatitis B virus (HBV) still remains a major global public health problem. Worldwide, two billion subjects have been infected, 350 million have a chronic infection and more than 600 000 die annually of HBV-related liver disease or hepatocellular carcinoma; new infections occur because of the presence of a large reservoir of chronic carriers of the virus. Since a decade several studies describe the interrelations between HBV and nuclear receptors and more particularly the peroxisome proliferator-activated receptors (PPARs). After a brief introduction, this review will make a rapid description of HBV incidence and biology. Then a report of the literature on the role of PPARs on viral transcription and replication will be developed. Finally, the role of HBV on PPARγ expression and activity will be discussed. Concluding remarks and perspectives will close this review.
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18
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Jung Y, Song S, Choi C. Peroxisome proliferator activated receptor γ agonists suppress TNFα-induced ICAM-1 expression by endothelial cells in a manner potentially dependent on inhibition of reactive oxygen species. Immunol Lett 2008; 117:63-9. [DOI: 10.1016/j.imlet.2007.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 11/30/2007] [Accepted: 12/04/2007] [Indexed: 01/19/2023]
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19
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Abstract
Hepatocellular carcinoma (HCC) is a worldwide health issue that has started receiving attention but is still poorly understood. However, the hepatitis B virus (HBV) and the hepatitis C virus (HCV) are known to be two major causative agents of HCC. They differ in their modes of infection, their treatment options, their genomes and their carcinogenic abilities. However, both share a link with HCC through alterations of the host genome. In order to continue in our search for the mechanisms behind viral hepatocarcinogenesis, the individual entities (HBV, HCV, HCC and host), their natural history, treatment options and genomic properties must be further understood. Additionally, an understanding of the genomics, the link between the entities, is crucial for the success of the ongoing search for therapeutic options for HCC. Similar to most types of cancer, hepatocarcinogenesis is a multistep process involving different genetic alterations that ultimately lead to malignant transformation of the hepatocyte. As technology advances and research continues, the genetic changes and influences among these entities will prove essential to improved diagnostic and therapeutic options. It remains a challenge to provide a clear picture of the connection between virus and cancer. We review (i) the epidemiological link between HBV/HCV infection to HCC; (ii) prevention and control of chronic hepatitis B or C in reducing HCC risk; and (iii) genetic characters of viruses and hosts and the mechanisms associated with HCC susceptibilities, with the intention of providing a direction for future research and treatment.
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Affiliation(s)
- Alexander Tan
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan
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20
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Gao J, Chen C, Hong L, Wang J, Du Y, Song J, Shao X, Zhang J, Han H, Liu J, Fan D. Expression of Jagged1 and its association with hepatitis B virus X protein in hepatocellular carcinoma. Biochem Biophys Res Commun 2007; 356:341-7. [PMID: 17359939 DOI: 10.1016/j.bbrc.2007.02.130] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/14/2007] [Indexed: 12/26/2022]
Abstract
Jagged1 is one of the ligands of Notch signaling pathway, which controls cellular proliferation and differentiation, and also plays important roles in various malignant tumors. However, the expression of Jagged1 in hepatocellular carcinoma (HCC) has not been elucidated, nor whether it is associated with hepatitis B virus X protein (HBx). In this study, we found that Jagged1 was highly expressed in 79.2% (42/53) of HCC tissues compared with adjacent nontumor liver (P <0.05), and its expression was found to be closely related with HBx (rs=0.522, P <0.001) in HCC tissues. Our in vitro study also showed that alteration of HBx expression in HCC cell lines led to a consistent change of Jagged1. Moreover, Jagged1 was found to co-localize and directly interact with HBx in HCC tissues and HBx expressed HCC cell lines. Our results reveal that Jagged1, which is regulated by HBx, may contribute to the development of HCC.
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Affiliation(s)
- Juan Gao
- Institute of Digestive Diseases, State Key Laboratory of Cancer Biology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, PR China
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21
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Kim JS, Rho BY, Lee TH, Lee JM, Kim SJ, Park JH. The interaction of hepatitis B virus X protein and protein phosphatase type 2 Calpha and its effect on IL-6. Biochem Biophys Res Commun 2006; 351:253-8. [PMID: 17055456 DOI: 10.1016/j.bbrc.2006.10.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 10/08/2006] [Indexed: 11/16/2022]
Abstract
HBx has been suggested as an important determinant mediating the pathological effects of HBV via interacting with various cellular proteins. To identify new HBx-interacting proteins and elucidate a possible mechanism associated with HBx and HBx-interacting proteins in hepatocellular carcinoma, yeast two-hybrid screening was performed. We identified a novel HBx-interacting protein, serine/threonine protein phosphatase PP2Calpha, and investigated the effects of PP2Calpha on HBx-mediated IL-6 regulation. The interaction between endogenous PP2Calpha, and HBx was confirmed by co-immunoprecipitation. Recombinant HBx dose-dependently reduced enzyme activity of recombinant PP2Calphain vitro. While ectopically expressed PP2Calpha in Cos-7 and Huh-7 cells reduced the expression of IL-6, overexpressed HBx with recombinant HBx-expressing adenovirus overcame PP2Calpha-mediated IL-6 downregulation. In the response of IL-6, HBx phosphorylated STAT3 and recovered PP2Calpha-mediated dephosphorylation of STAT3. These results supported that HBx might play a crucial role in HBV-associated hepatocarcinogenesis even in cases where cells express a negative regulator, PP2Calpha.
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Affiliation(s)
- Ji Su Kim
- Department of Microbiology and Brain Korea 21 Project for Medical Sciences, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
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Han J, Ding L, Yuan B, Yang X, Wang X, Li J, Lu Q, Huang C, Ye Q. Hepatitis B virus X protein and the estrogen receptor variant lacking exon 5 inhibit estrogen receptor signaling in hepatoma cells. Nucleic Acids Res 2006; 34:3095-106. [PMID: 16757575 PMCID: PMC1475750 DOI: 10.1093/nar/gkl389] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hepatitis B virus (HBV) X protein (HBx) is considered to play a role in the development of hepatocellular carcinoma (HCC) during HBV infection. HCC was shown to be more prevalent in men than in women. Estrogen, which exerts its biological function through estrogen receptor (ER), can inhibit HBV replication. ERDelta5, an ERalpha variant lacking exon 5, was found to be preferentially expressed in patients with HCC compared with patients with normal livers. Here, we report the biological role of ERDelta5 and a novel link between HBx and ERalpha signaling in hepatoma cells. ERDelta5 interacts with ERalpha in vitro and in vivo and functions as a dominant negative receptor. Both ERalpha and ERDelta5 associate with HBx. HBx decreases ERalpha-dependent transcriptional activity, and HBx and ERDelta5 have additive effect on suppression of ERalpha transactivation. The HBx deletion mutant that lacks the ERalpha-binding site abolishes the HBx repression of ERalpha. HBx, ERalpha and histone deacetylase 1 (HDAC1) form a ternary complex. Trichostatin A, a specific inhibitor of HDAC enzyme, can restore the transcriptional activity of ERalpha inhibited by HBx. Our data suggest that HBx and ERDelta5 may play a negative role in ERalpha signaling and that ERalpha agonists may be developed for HCC therapy.
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Affiliation(s)
| | | | | | | | | | | | - Qiujun Lu
- Beijing Institute of Radiation MedicineBeijing 100850, People's Republic of China
| | | | - Qinong Ye
- To whom correspondence should be addressed. Tel: +8610 6818 0809; Fax: +8610 6824 8045;
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23
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Tang H, Delgermaa L, Huang F, Oishi N, Liu L, He F, Zhao L, Murakami S. The transcriptional transactivation function of HBx protein is important for its augmentation role in hepatitis B virus replication. J Virol 2005; 79:5548-56. [PMID: 15827169 PMCID: PMC1082733 DOI: 10.1128/jvi.79.9.5548-5556.2005] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The role and functional domain of hepatitis B virus (HBV) X protein (HBx) in regulating HBV transcription and replication were investigated with a transient transfection system in the human hepatoma cell line HepG2 using wild-type or HBx-minus HBV genome constructs and a series of deletion or mutation HBx expression plasmids. We show here that HBx has augmentation effects on HBV transcription and replication as a HBV mutant genome with defective X gene led to decreased levels of 3.5-kb HBV RNA and HBV replication intermediates and that these decreases can be restored by either transient ectopic expression of HBx or a stable HBx expression cell line. The C-terminal two-thirds (amino acids [aa] 51 to 154), which contain the transactivation domain, is required for this function of HBx; the N-terminal one-third (aa 1 to 50) is not required. Using the alanine scanning mutagenesis strategy, we demonstrated that the regions between aa 52 to 65 and 88 to 154 are important for the augmentation function of HBx in HBV replication. By the luciferase reporter gene analysis, we found that the transactivation and coactivation activities of HBx coincide well with its augmentation function in HBV transcription and replication. These results suggest that HBx has an important role in stimulating HBV transcription and replication and that the transcriptional transactivation function of HBx may be critical for its augmentation effect on HBV replication.
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Affiliation(s)
- Hong Tang
- Department of Molecular Oncology, Cancer Research Institute, Kanazawa University, Takara-machi 13-1, Kanazawa 920-0934, Japan
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Boya P, Pauleau AL, Poncet D, Gonzalez-Polo RA, Zamzami N, Kroemer G. Viral proteins targeting mitochondria: controlling cell death. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1659:178-89. [PMID: 15576050 DOI: 10.1016/j.bbabio.2004.08.007] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 07/20/2004] [Accepted: 08/16/2004] [Indexed: 01/21/2023]
Abstract
Mitochondrial membrane permeabilization (MMP) is a critical step regulating apoptosis. Viruses have evolved multiple strategies to modulate apoptosis for their own benefit. Thus, many viruses code for proteins that act on mitochondria and control apoptosis of infected cells. Viral proapoptotic proteins translocate to mitochondrial membranes and induce MMP, which is often accompanied by mitochondrial swelling and fragmentation. From a structural point of view, all the viral proapoptotic proteins discovered so far contain amphipathic alpha-helices that are necessary for the proapoptotic effects and seem to have pore-forming properties, as it has been shown for Vpr from human immunodeficiency virus-1 (HIV-1) and HBx from hepatitis B virus (HBV). In contrast, antiapoptotic viral proteins (e.g., M11L from myxoma virus, F1L from vaccinia virus and BHRF1 from Epstein-Barr virus) contain mitochondrial targeting sequences (MTS) in their C-terminus that are homologous to tail-anchoring domains. These domains are similar to those present in many proteins of the Bcl-2 family and are responsible for inserting the protein in the outer mitochondrial membrane leaving the N-terminus of the protein facing the cytosol. The antiapoptotic proteins K7 and K15 from avian encephalomyelitis virus (AEV) and viral mitochondria inhibitor of apoptosis (vMIA) from cytomegalovirus are capable of binding host-specific apoptosis-modulatory proteins such as Bax, Bcl-2, activated caspase 3, CAML, CIDE-B and HAX. In conclusion, viruses modulate apoptosis at the mitochondrial level by multiple different strategies.
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Affiliation(s)
- Patricia Boya
- Centre National de la Recherche Scientifique, UMR 8125, Institut Gustave Roussy, Pavillon de Recherche 1, 39 rue Camille-Desmoulins, F-94805 Villejuif, France
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