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Dezhbord M, Kim SH, Park S, Lee DR, Kim N, Won J, Lee AR, Kim DS, Kim KH. Novel role of MHC class II transactivator in hepatitis B virus replication and viral counteraction. Clin Mol Hepatol 2024; 30:539-560. [PMID: 38741238 PMCID: PMC11261224 DOI: 10.3350/cmh.2024.0060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/02/2024] [Accepted: 05/13/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND/AIMS The major histocompatibility class II (MHC II) transactivator, known as CIITA, is induced by Interferon gamma (IFN-γ) and plays a well-established role in regulating the expression of class II MHC molecules in antigen-presenting cells. METHODS Primary human hepatocytes (PHH) were isolated via therapeutic hepatectomy from two donors. The hepatocellular carcinoma (HCC) cell lines HepG2 and Huh7 were used for the mechanistic study, and HBV infection was performed in HepG2-NTCP cells. HBV DNA replication intermediates and secreted antigen levels were measured using Southern blotting and ELISA, respectively. RESULTS We identified a non-canonical function of CIITA in the inhibition of hepatitis B virus (HBV) replication in both HCC cells and patient-derived PHH. Notably, in vivo experiments demonstrated that HBV DNA and secreted antigen levels were significantly decreased in mice injected with the CIITA construct. Mechanistically, CIITA inhibited HBV transcription and replication by suppressing the activity of HBV-specific enhancers/promoters. Indeed, CIITA exerts antiviral activity in hepatocytes through ERK1/2-mediated down-regulation of the expression of hepatocyte nuclear factor 1α (HNF1α) and HNF4α, which are essential factors for virus replication. In addition, silencing of CIITA significantly abolished the IFN-γ-mediated anti-HBV activity, suggesting that CIITA mediates the anti-HBV activity of IFN-γ to some extent. HBV X protein (HBx) counteracts the antiviral activity of CIITA via direct binding and impairing its function. CONCLUSION Our findings reveal a novel antiviral mechanism of CIITA that involves the modulation of the ERK pathway to restrict HBV transcription. Additionally, our results suggest the possibility of a new immune avoidance mechanism involving HBx.
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Affiliation(s)
- Mehrangiz Dezhbord
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Seong Ho Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Soree Park
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Da Rae Lee
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Nayeon Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Juhee Won
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
- Department of Pharmacology, School of Medicine, Konkuk University, Seoul, Korea
| | - Ah Ram Lee
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Dong-Sik Kim
- Department of Surgery, Division of HBP Surgery and Liver Transplantation, College of Medicine, Korea University, Seoul, Korea
| | - Kyun-Hwan Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea
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Mghezzi-Habellah M, Prochasson L, Jalinot P, Mocquet V. Viral Subversion of the Chromosome Region Maintenance 1 Export Pathway and Its Consequences for the Cell Host. Viruses 2023; 15:2218. [PMID: 38005895 PMCID: PMC10674744 DOI: 10.3390/v15112218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/26/2023] Open
Abstract
In eukaryotic cells, the spatial distribution between cytoplasm and nucleus is essential for cell homeostasis. This dynamic distribution is selectively regulated by the nuclear pore complex (NPC), which allows the passive or energy-dependent transport of proteins between these two compartments. Viruses possess many strategies to hijack nucleocytoplasmic shuttling for the benefit of their viral replication. Here, we review how viruses interfere with the karyopherin CRM1 that controls the nuclear export of protein cargoes. We analyze the fact that the viral hijacking of CRM1 provokes are-localization of numerous cellular factors in a suitable place for specific steps of viral replication. While CRM1 emerges as a critical partner for viruses, it also takes part in antiviral and inflammatory response regulation. This review also addresses how CRM1 hijacking affects it and the benefits of CRM1 inhibitors as antiviral treatments.
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Affiliation(s)
| | | | | | - Vincent Mocquet
- Laboratoire de Biologie et Modélisation de la Cellule, Ecole Normale Supérieure-Lyon, Université Claude Bernard Lyon, U1293, UMR5239, 69364 Lyon, France; (M.M.-H.); (L.P.); (P.J.)
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3
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Brezgin SA, Kostyusheva AP, Ponomareva NI, Gegechkori VI, Kirdyashkina NP, Ayvasyan SR, Dmitrieva LN, Kokoreva LN, Chulanov VP, Kostyushev DS. HBx Protein Potentiates Hepatitis B Virus Reactivation. Mol Biol 2022. [DOI: 10.1134/s0026893322050041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Identification of Estradiol Benzoate as an Inhibitor of HBx Using Inducible Stably Transfected HepG2 Cells Expressing HiBiT Tagged HBx. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27155000. [PMID: 35956950 PMCID: PMC9370419 DOI: 10.3390/molecules27155000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022]
Abstract
HBx plays a significant role in the cccDNA epigenetic modification regulating the hepatitis B virus (HBV) life cycle and in hepatocyte proliferation and carcinogenesis. By using the sleeping-beauty transposon system, we constructed a tetracycline-induced HBx-expressing stable cell line, SBHX21. HBx with a HiBiT tag can be quickly detected utilizing a NanoLuc-based HiBiT detection system. By screening a drug library using SBHX21 cells, we identified estradiol benzoate as a novel anti-HBx agent. Estradiol benzoate also markedly reduced the production of HBeAg, HBsAg, HBV pgRNA, and HBV DNA in a dose-dependent manner, suggesting that estradiol benzoate could be an anti-HBV agent. Docking model results revealed that estradiol benzoate binds to HBx at TRP87 and TRP107. Collectively, our results suggest that estradiol benzoate inhibits the HBx protein and HBV transcription and replication, which may serve as a novel anti-HBV molecular compound for investigating new treatment strategies for HBV infection.
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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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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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Phosphorylation of Phylogenetically Conserved Amino Acid Residues Confines HBx within Different Cell Compartments of Human Hepatocarcinoma Cells. Molecules 2021; 26:molecules26051254. [PMID: 33652602 PMCID: PMC7956559 DOI: 10.3390/molecules26051254] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/20/2021] [Accepted: 02/20/2021] [Indexed: 01/05/2023] Open
Abstract
Hepatitis B virus (HBV) is a circular, and partially double-stranded DNA virus. Upon infection, the viral genome is translocated into the cell nucleus, generating the covalently closed circular DNA (cccDNA) intermediate, and forming a mini chromosome. HBV HBx is a small protein displaying multiple roles in HBV-infected cells, and in different subcellular locations. In the nucleus, the HBx protein is required to initiate and maintain viral transcription from the viral mini chromosome. In contrast, HBx also functions in the cytoplasm, where it is able to alter multiple cellular functions such as mitochondria metabolism, apoptosis and signal transduction pathways. It has been reported that in cultured cells, at low expression levels, the HBx protein is localized in the nucleus, whereas at high expression levels, it accumulates in the cytoplasm. This dynamic subcellular distribution of HBx might be essential to exert its multiple roles during viral infection. However, the mechanism that regulates different subcellular localizations of the HBx protein is unknown. We have previously taken a bioinformatics approach to investigate whether HBx might be regulated via post-translational modification, and we have proposed that the multiple nucleocytoplasmic functions of HBx might be regulated by an evolutionarily conserved mechanism via phosphorylation. In the current study, phylogenetically conserved amino acids of HBx with a high potential of phosphorylation were targeted for site-directed mutagenesis. Two conserved serine (Ser25 and Ser41), and one conserved threonine (Thr81) amino acids were replaced by either alanine or aspartic acid residues to simulate an unphosphorylated or phosphorylated state, respectively. Human hepatoma cells were transfected with increasing amounts of the HBx DNA constructs, and the cells were analyzed by fluorescence microscopy. Together, our results show that the nucleocytoplasmic distribution of the HBx protein could be regulated by phosphorylation since some of the modified proteins were mainly confined to distinct subcellular compartments. Remarkably, both HBx Ser41A, and HBx Thr81D proteins were predominantly localized within the nuclear compartment throughout the different expression levels of HBx mutants.
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Ngo MHT, Jeng HY, Kuo YC, Nanda JD, Brahmadhi A, Ling TY, Chang TS, Huang YH. The Role of IGF/IGF-1R Signaling in Hepatocellular Carcinomas: Stemness-Related Properties and Drug Resistance. Int J Mol Sci 2021; 22:ijms22041931. [PMID: 33669204 PMCID: PMC7919800 DOI: 10.3390/ijms22041931] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 12/12/2022] Open
Abstract
Insulin-like Growth Factor (IGF)/IGF-1 Receptor (IGF-1R) signaling is known to regulate stem cell pluripotency and differentiation to trigger cell proliferation, organ development, and tissue regeneration during embryonic development. Unbalanced IGF/IGF-1R signaling can promote cancer cell proliferation and activate cancer reprogramming in tumor tissues, especially in the liver. Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, with a high incidence and mortality rate in Asia. Most patients with advanced HCC develop tyrosine kinase inhibitor (TKI)-refractoriness after receiving TKI treatment. Dysregulation of IGF/IGF-1R signaling in HCC may activate expression of cancer stemness that leads to TKI refractoriness and tumor recurrence. In this review, we summarize the evidence for dysregulated IGF/IGF-1R signaling especially in hepatitis B virus (HBV)-associated HCC. The regulation of cancer stemness expression and drug resistance will be highlighted. Current clinical treatments and potential therapies targeting IGF/IGF-1R signaling for the treatment of HCC will be discussed.
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Affiliation(s)
- Mai-Huong Thi Ngo
- International PhD Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (M.-H.T.N.); (J.D.N.); (A.B.)
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Han-Yin Jeng
- Research Center of Cell Therapy and Regeneration Medicine, Taipei Medical University, Taipei 11031, Taiwan; (H.-Y.J.); (Y.-C.K.)
| | - Yung-Che Kuo
- Research Center of Cell Therapy and Regeneration Medicine, Taipei Medical University, Taipei 11031, Taiwan; (H.-Y.J.); (Y.-C.K.)
| | - Josephine Diony Nanda
- International PhD Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (M.-H.T.N.); (J.D.N.); (A.B.)
| | - Ageng Brahmadhi
- International PhD Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (M.-H.T.N.); (J.D.N.); (A.B.)
| | - Thai-Yen Ling
- Department and Graduate Institute of Pharmacology, National Taiwan University, Taipei 11031, Taiwan
- Correspondence: (T.-Y.L.); (T.-S.C.); (Y.-H.H.); Tel.: +886-2-2312-3456 (ext. 8-8322) (T.-Y.L.); +886-5-3621-000 (ext. 2242) (T.-S.C.); +886-2-2736-1661 (ext. 3150) (Y.-H.H.)
| | - Te-Sheng Chang
- School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan 33382, Taiwan
- Division of Internal Medicine, Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan
- Correspondence: (T.-Y.L.); (T.-S.C.); (Y.-H.H.); Tel.: +886-2-2312-3456 (ext. 8-8322) (T.-Y.L.); +886-5-3621-000 (ext. 2242) (T.-S.C.); +886-2-2736-1661 (ext. 3150) (Y.-H.H.)
| | - Yen-Hua Huang
- International PhD Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (M.-H.T.N.); (J.D.N.); (A.B.)
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Research Center of Cell Therapy and Regeneration Medicine, Taipei Medical University, Taipei 11031, Taiwan; (H.-Y.J.); (Y.-C.K.)
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Center for Reproductive Medicine, Taipei Medical University Hospital, Taipei 11031, Taiwan
- Comprehensive Cancer Center, Taipei Medical University, Taipei 11031, Taiwan
- Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei 11031, Taiwan
- PhD Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan
- Correspondence: (T.-Y.L.); (T.-S.C.); (Y.-H.H.); Tel.: +886-2-2312-3456 (ext. 8-8322) (T.-Y.L.); +886-5-3621-000 (ext. 2242) (T.-S.C.); +886-2-2736-1661 (ext. 3150) (Y.-H.H.)
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Hu B, Yu L, Zhu N, Xie J. Cellular UAP56 interacts with the HBx protein of the hepatitis B virus and is involved in viral RNA nuclear export in hepatocytes. Exp Cell Res 2020; 390:111929. [DOI: 10.1016/j.yexcr.2020.111929] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 01/29/2023]
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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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Tsuchiya H, Amisaki M, Takenaga A, Honjo S, Fujiwara Y, Shiota G. HBx and c-MYC Cooperate to Induce URI1 Expression in HBV-Related Hepatocellular Carcinoma. Int J Mol Sci 2019; 20:ijms20225714. [PMID: 31739577 PMCID: PMC6888623 DOI: 10.3390/ijms20225714] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 01/04/2023] Open
Abstract
Unconventional prefoldin RNA polymerase II subunit 5 interactor (URI1) has emerged as an oncogenic driver in hepatocellular carcinoma (HCC). Although the hepatitis B virus (HBV) represents the most common etiology of HCC worldwide, it is unknown whether URI1 plays a role in HBV-related HCC (HCC-B). In the present study, we investigated URI1 expression and its underlying mechanism in HCC-B tissues and cell lines. URI1 gene-promoter activity was determined by a luciferase assay. Human HCC-B samples were used for a chromatin immunoprecipitation assay. We found that c-MYC induced URI1 expression and activated the URI1 promoter through the E-box in the promoter region while the HBx protein significantly enhanced it. The positivity of URI1 expression was significantly higher in HCC-B tumor tissues than in non-HBV-related HCC tumor tissues, suggesting that a specific mechanism underlies URI1 expression in HCC-B. In tumor tissues from HCC-B patients, a significantly higher level of c-MYC was recruited to the E-box than in non-tumor tissues. These results suggest that HBx and c-MYC are involved in URI1 expression in HCC-B. URI1 expression may play important roles in the development and progression of HCC-B because HBx and c-MYC are well-known oncogenic factors in the virus and host, respectively.
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Affiliation(s)
- Hiroyuki Tsuchiya
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
- Correspondence: ; Tel./Fax: +81-859-38-6435
| | - Masataka Amisaki
- Division of Surgical Oncology, Department of Surgery, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
| | - Ai Takenaga
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
| | - Soichiro Honjo
- Division of Surgical Oncology, Department of Surgery, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
| | - Yoshiyuki Fujiwara
- Division of Surgical Oncology, Department of Surgery, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
| | - Goshi Shiota
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan
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Jindal A, Thadi A, Shailubhai K. Hepatocellular Carcinoma: Etiology and Current and Future Drugs. J Clin Exp Hepatol 2019; 9:221-232. [PMID: 31024205 PMCID: PMC6477125 DOI: 10.1016/j.jceh.2019.01.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/14/2019] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is swiftly increasing in prevalence globally with a high mortality rate. The progression of HCC in patients is induced with advanced fibrosis, mainly cirrhosis, and hepatitis. The absence of proper preventive or curative treatment methods encouraged extensive research against HCC to develop new therapeutic strategies. The Food and Drug Administration-approved Nexavar (sorafenib) is used in the treatment of patients with unresectable HCC. In 2017, Stivarga (regorafenib) and Opdivo (nivolumab) got approved for patients with HCC after being treated with sorafenib, and in 2018, Lenvima (lenvatinib) got approved for patients with unresectable HCC. But, owing to the rapid drug resistance development and toxicities, these treatment options are not completely satisfactory. Therefore, there is an urgent need for new systemic combination therapies that target different signaling mechanisms, thereby decreasing the prospect of cancer cells developing resistance to treatment. In this review, HCC etiology and new therapeutic strategies that include currently approved drugs and other potential candidates of HCC such as Milciclib, palbociclib, galunisertib, ipafricept, and ramucirumab are evaluated.
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Key Words
- AMP, adenosine monophosphate
- AMPK, AMP-activated protein kinase
- ATP, adenosine 5′-triphosphate
- BMF, Bcl2 modifying factor
- BMI, body mass index
- CDK, cyclin-dependent kinase
- CTGF, connective tissue growth factor
- CTL, cytotoxic T lymphocyte
- CTLA, cytotoxic T-lymphocyte-associated protein
- ECM, extracellular matrix
- EFGR, endothelial growth factor receptor
- EGFR, epidermal growth factor receptor
- EMT, Epithelial–mesenchymal transition
- ERK, extracellular signal-regulated kinase
- FDA, Food and Drug Administration
- GFG, fibroblast growth factor
- HBV, hepatitis B virus
- HBcAg, hepatitis B core antibody
- HBsAg, HBV surface antigen
- HCC, Hepatocellular carcinoma
- HCV, hepatitis B virus
- HDV, hepatitis D virus
- HIF, hypoxia-inducible factor
- HIV, human immunodeficiency virus
- IGFR, insulin-like growth factor
- JAK, janus kinase
- MAPK, mitogen-activated protein kinase
- MDSC, myeloid-derived suppressor cell
- NASH, nonalcoholic steatohepatitis
- NK, natural killer
- NKT, natural killer T cell
- ORR, objective response rate
- OS, overall survival
- PAPSS1, 3′-phosphoadenosine 5′-phosphosulfate synthase 1
- PD-L1, programmed death ligand1
- PD1, programmed cell death protein 1
- PDGFR, platelet-derived growth factor receptor
- PEDF, pigment epithelium-derived factor
- PFS, progression-free survival
- PI3K, phosphoinositide 3-kinases
- PTEN, phosphatase and tensin homolog
- PUMA, p53 upregulated modulator of apoptosis
- RFA, radiofrequency ablation
- Rb, retinoblastoma protein
- SCF, stem cell factor
- SHP1, src homology 2 domain–containing phosphatase 1
- STAT3, signal transducer and activator of transcription 3
- TACE, transarterial chemoembolization
- TGF 1, transforming growth factor-1
- TK, tyrosine kinase
- TKI, Tyrosine kinase inhibitor
- TRKA, tropomyosin receptor kinase A
- Treg, regulatory T cells
- VEGF, vascular endothelial growth factor
- VEGFR, vascular endothelial growth factor receptor
- bFGF, basic fibroblast growth factor
- combination therapy
- cyclin-dependent kinase inhibitors
- hepatocellular carcinoma
- hepatology
- tyrosine kinase inhibitors
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Affiliation(s)
- Aastha Jindal
- Research and Development Center, Baruch S. Blumberg Institute, Doylestown, PA 18902, USA
- Address for correspondence: Aastha Jindal, Research and Development Center, Baruch S. Blumberg Institute, Doylestown, PA 18902, USA.
| | - Anusha Thadi
- Research and Development Center, Baruch S. Blumberg Institute, Doylestown, PA 18902, USA
| | - Kunwar Shailubhai
- Research and Development Center, Baruch S. Blumberg Institute, Doylestown, PA 18902, USA
- Research & Development, Tiziana Lifesciences, Doylestown, PA 18902, USA
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Zhang JF, Xiong HL, Cao JL, Wang SJ, Guo XR, Lin BY, Zhang Y, Zhao JH, Wang YB, Zhang TY, Yuan Q, Zhang J, Xia NS. A cell-penetrating whole molecule antibody targeting intracellular HBx suppresses hepatitis B virus via TRIM21-dependent pathway. Am J Cancer Res 2018; 8:549-562. [PMID: 29290826 PMCID: PMC5743566 DOI: 10.7150/thno.20047] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022] Open
Abstract
Rationale: Monoclonal antibodies (mAbs) mostly targeting extracellular or cell surface molecules have been widely used in the treatment of various diseases. However, mAbs cannot pass through the cell membrane as efficiently as small compounds, thus limiting their use against intracellular targets. Methods to shuttle antibodies into living cells may largely expand research and application in areas based on mAbs. Hepatitis B virus X protein (HBx) is an important intracellular multi-functional viral protein in the life cycle of hepatitis B virus (HBV). HBx plays essential roles in virus infection and replication and is strongly associated with HBV-related carcinogenesis. Methods: In this study, we developed a cell-penetrating whole molecule antibody targeting HBx (9D11-Tat) by the fusion of a cell penetrating peptide (CPP) on the C-terminus of the heavy chain of a potent mAb specific to HBx (9D11). The anti-HBV effect and mechanism of 9D11-Tat were investigated in cell and mouse models mimicking chronic HBV infection. Results: Our results demonstrated that the recombinant 9D11-Tat antibody could efficiently internalize into living cells and significantly suppress viral transcription, replication, and protein production both in vitro and in vivo. Further analyses suggested the internalized 9D11-Tat antibody could greatly reduce intracellular HBx via Fc binding receptor TRIM21-mediated protein degradation. This process simultaneously stimulated the activations of NF-κB, AP-1, and IFN-β, which promoted an antiviral state of the host cell. Conclusion: In summary, our study offers a new approach to target intracellular pathogenesis-related protein by engineered cell-penetrating mAb expanding their potential for therapeutic applications. Moreover, the 9D11-Tat antibody may provide a novel therapeutic agent against human chronic HBV infection.
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Chutiwitoonchai N, Mano T, Kakisaka M, Sato H, Kondoh Y, Osada H, Kotani O, Yokoyama M, Sato H, Aida Y. Inhibition of CRM1-mediated nuclear export of influenza A nucleoprotein and nuclear export protein as a novel target for antiviral drug development. Virology 2017; 507:32-39. [PMID: 28399435 PMCID: PMC7111614 DOI: 10.1016/j.virol.2017.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 12/18/2022]
Abstract
An anti-influenza compound, DP2392-E10 based on inhibition of the nuclear export function of the viral nucleoprotein-nuclear export signal 3 (NP-NES3) domain was successfully identified by our previous high-throughput screening system. Here, we demonstrated that DP2392-E10 exerts its antiviral effect by inhibiting replication of a broad range of influenza A subtypes. In regard to the molecular mechanism, we revealed that DP2392-E10 inhibits nuclear export of both viral NP and nuclear export protein (NEP). More specifically, in vitro pull-down assays revealed that DP2392-E10 directly binds cellular CRM1, which mediates nuclear export of NP and NEP. In silico docking suggested that DP2392-E10 binds at a region close to the HEAT9 and HEAT10 domains of CRM1. Together, these results indicate that the CRM1-mediated nuclear export function of influenza virus represents a new potential target for antiviral drug development, and also provide a core structure for a novel class of inhibitors that target this function.
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Affiliation(s)
| | - Takafumi Mano
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Michinori Kakisaka
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hirotaka Sato
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yasumitsu Kondoh
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Osada
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Osamu Kotani
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Masaru Yokoyama
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Hironori Sato
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Yoko Aida
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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15
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Deng JJ, Kong KYE, Gao WW, Tang HMV, Chaudhary V, Cheng Y, Zhou J, Chan CP, Wong DKH, Yuen MF, Jin DY. Interplay between SIRT1 and hepatitis B virus X protein in the activation of viral transcription. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:491-501. [PMID: 28242208 DOI: 10.1016/j.bbagrm.2017.02.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/13/2017] [Accepted: 02/20/2017] [Indexed: 12/14/2022]
Abstract
Hepatitis B virus (HBV) genome is organized into a minichromosome known as covalently closed circular DNA (cccDNA), which serves as the template for all viral transcripts. SIRT1 is an NAD+-dependent protein deacetylase which activates HBV transcription by promoting the activity of cellular transcription factors and coactivators. How SIRT1 and viral transactivator X protein (HBx) might affect each other remains to be clarified. In this study we show synergy and mutual dependence between SIRT1 and HBx in the activation of HBV transcription. All human sirtuins SIRT1 through SIRT7 activated HBV gene expression. The steady-state levels of SIRT1 protein were elevated in HBV-infected liver tissues and HBV-replicating hepatoma cells. SIRT1 interacted with HBx and potentiated HBx transcriptional activity on precore promoter and covalently closed circular DNA (cccDNA) likely through a deacetylase-independent mechanism, leading to more robust production of cccDNA, pregenomic RNA and surface antigen. SIRT1 and HBx proteins were more abundant when both were expressed. SIRT1 promoted the recruitment of HBx as well as cellular transcriptional factors and coactivators such as PGC-1α and FXRα to cccDNA. Depletion of SIRT1 suppressed HBx recruitment. On the other hand, SIRT1 recruitment to cccDNA was compromised when HBx was deficient. Whereas pharmaceutical agonists of SIRT1 such as resveratrol activated HBV transcription, small-molecule inhibitors of SIRT1 including sirtinol and Ex527 exhibited anti-HBV activity. Taken together, our findings revealed not only the interplay between SIRT1 and HBx in the activation of HBV transcription but also new strategies and compounds for developing antivirals against HBV.
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Affiliation(s)
- Jian-Jun Deng
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; Shaanxi Key Laboratory of Biodegradable Materials, College of Chemical Engineering, Northwest University, 229 Taibai Road North, Xi'an 710069, China; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Ka-Yiu Edwin Kong
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Wei-Wei Gao
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Hei-Man Vincent Tang
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Vidyanath Chaudhary
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Yun Cheng
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Jie Zhou
- Department of Microbiology, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong
| | - Chi-Ping Chan
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Danny Ka-Ho Wong
- State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong; Department of Medicine, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong
| | - Man-Fung Yuen
- State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong; Department of Medicine, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong
| | - Dong-Yan Jin
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong; State Key Laboratory for Liver Research, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong.
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16
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Xie QL, Liu Y, Zhu Y. Chromosome region maintenance 1 expression and its association with clinical pathological features in primary carcinoma of the liver. Exp Ther Med 2016; 12:59-68. [PMID: 27347018 PMCID: PMC4907041 DOI: 10.3892/etm.2016.3283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 02/19/2016] [Indexed: 12/18/2022] Open
Abstract
Liver cancer is the third leading cause of cancer-associated mortality worldwide. Recurrence and metastasis are the major factors affecting the prognosis; thus, investigation of the underlying molecular mechanisms of invasion and metastasis, and detection of novel drug target may improve the mortality rate of liver cancer patients. Chromosome region maintenance 1 (CRM1) recognizes specific leucine-rich nuclear export signal sequences, and its overexpression is associated with tumor-suppressor gene inactivation, proliferation, invasion and resistance to chemotherapy. The aim of the present study was to examine the association of CRM1 expression with the clinical and pathological features of primary liver cancer. In total, 152 cases diagnosed with liver cancer were included. CRM1 expression was detected in cancer tissues and adjacent normal tissues by immunohistochemical assay. No statistically significant difference was found between the CRM1 expression levels in tumor and adjacent normal tissues (P=0.106). However, CRM1 expression in adjacent normal tissues was higher compared with that in tumor tissues in the negative hepatitis B envelope antigen (HBeAg; P=0.029) and low differentiation (P=0.004) groups. In tumor tissues, CRM1 expression was significantly correlated with differentiation (P=0.045), whereas in adjacent normal tissues, CRM1 expression was significantly correlated with the tumor diameter (P=0.004). Therefore, it can be concluded that CRM1 is highly expressed in both tumor and adjacent normal tissues. Furthermore, CRM1 expression is associated with the tumor differentiation degree and diameter. Lower differentiation and larger tumor diameter resulted in higher CRM1 expression in adjacent normal tissues, and higher tendency for invasion and metastasis. In addition, the risk of invasion and metastasis remains in chronic hepatitis B patients with negative HBeAg.
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Affiliation(s)
- Qiao-Ling Xie
- Department of Infectious Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116000, P.R. China
| | - Yue Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116000, P.R. China
| | - Ying Zhu
- Department of Infectious Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116000, P.R. China
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17
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Shi Y, Zhang H, Han Z, Mi X, Zhang W, Lv M. HBx interacted with Smad4 to deprive activin a growth inhibition function in hepatocyte HL7702 on CRM1 manner. Tumour Biol 2016; 37:3405-15. [PMID: 26449823 DOI: 10.1007/s13277-015-4076-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/13/2015] [Indexed: 01/16/2023] Open
Abstract
Hepatitis B virus (HBV) is implicated in the pathogenesis of hepatocellular carcinoma, which has been found to be associated with TGF-beta signaling. Activin A is a TGF-β family cytokine that exhibits cell proliferation inhibition on normal hepatocyte. How HBV-encoded X oncoprotein play in activin's activity on hepatocyte has not been developed. In this study, a nontumor hepatic cell line HL7702 with HBX ectogenic expression has been established. MTT and BrdU assays showed that HBx promoted growth of HL7702 cells in vitro and downregulated activin signaling. Deregulated activin signaling pathway by HBX failed to activate target gene p21/waf1 and p15 transcription. In addition, mammalian two-hybrid and coimmunoprecipitation assays revealed that HBX could directly interact with activin signaling transduction protein Smad4, making activated Smad2/3/4 nucleus translocation suppressed. Furthermore, we detected that leptomycin B, the inhibitor of CRM1 protein, could recover nuclear translocation of endogenous Smads complex in HL7702 with HBX expression, indicating that HBX antagonized Smads nucleus translocation, at least partially, on CRM1-dependent manner. Leptomycin B was found to have antigrowth activity on HBX-expressed HL7702, according to its antitumor function in previous study. Above all, HBX antagonized activin signaling in normal human liver cells by interacting with Smad4 might one of the considerable causes of HBX-induced hepatocyte transformation, which deprived activin's cell growth inhibition function at an early stage of tumorigenesis.
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Affiliation(s)
- Ying Shi
- Institute of Translational Medicine, First Hospital of Jilin University, Changchun, People's Republic of China
| | - Haipeng Zhang
- The First Clinical Medical College of Jilin University, Changchun, People's Republic of China
| | - Zhu Han
- Institute of Translational Medicine, First Hospital of Jilin University, Changchun, People's Republic of China
| | - Xuguang Mi
- Tumor Biological Treatment Center of Jilin Province People's Hospital, Changchun, People's Republic of China
| | - Wenyan Zhang
- Institute of Translational Medicine, First Hospital of Jilin University, Changchun, People's Republic of China.
| | - Mingyu Lv
- Institute of Translational Medicine, First Hospital of Jilin University, Changchun, People's Republic of China.
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18
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Kongkavitoon P, Tangkijvanich P, Hirankarn N, Palaga T. Hepatitis B Virus HBx Activates Notch Signaling via Delta-Like 4/Notch1 in Hepatocellular Carcinoma. PLoS One 2016; 11:e0146696. [PMID: 26766040 PMCID: PMC4713073 DOI: 10.1371/journal.pone.0146696] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 12/20/2015] [Indexed: 12/12/2022] Open
Abstract
Hepatitis virus B (HBV) infection is one of the major causes of hepatocellular carcinomas (HCC). HBx protein encoded in HBV genome is one of the key viral factors leading to malignant transformation of infected cells. HBx functions by interfering with cellular functions, causing aberration in cellular behaviour and transformation. Notch signalling is a well-conserved pathway involved in cellular differentiation, cell survival and cell death operating in various types of cells. Aberration in the Notch signalling pathways is linked to various tumors, including HCC. The role of HBx on the Notch signalling in HCC, however, is still controversial. In this study, we reported that HBV genome-containing HCC cell line HepG2 (HepG2.2.15) expressed higher Notch1 and Delta-like 4 (Dll4), compared to the control HepG2 without HBV genome. This upregulation coincided with increased appearance of the cleavage of Notch1, indicating constitutively activated Notch signalling. Silencing of HBx specifically reduced the level of Dll4 and cleaved Notch1. The increase in Dll4 level was confirmed in clinical specimens of HCC lesion, in comparison with non-tumor lesions. Using specific signalling pathway inhibitors, we found that MEK1/2, PI3K/AKT and NF-κB pathways are critical for HBx-mediated Dll4 upregulation. Silencing of HBx clearly decreased the level of phosphorylation of Akt and Erk1/2. Upon silencing of Dll4 in HepG2.2.15, decreased cleaved Notch1, increased apoptosis and cell cycle arrest were observed, suggesting a critical role of HBx-Dll4-Notch1 axis in regulating cell survival in HCC. Furthermore, clonogenic assay confirmed the important role of Dll4 in regulating cell survival of HBV-genome containing HCC cell line. Taken together, we reported a link between HBx and the Notch signalling in HCC that affects cell survival of HCC, which can be a potential target for therapy.
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Affiliation(s)
- Pornrat Kongkavitoon
- Center of Excellence in Immunology and Immune-mediated Diseases, Chulalongkorn University, Bangkok, Thailand
- Interdisciplinary Graduate Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Pisit Tangkijvanich
- Research Unit of Hepatitis and Liver Cancer, Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Nattiya Hirankarn
- Center of Excellence in Immunology and Immune-mediated Diseases, Chulalongkorn University, Bangkok, Thailand
- Interdisciplinary Graduate Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- * E-mail: (TP); (NH)
| | - Tanapat Palaga
- Center of Excellence in Immunology and Immune-mediated Diseases, Chulalongkorn University, Bangkok, Thailand
- Interdisciplinary Graduate Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- * E-mail: (TP); (NH)
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19
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Moyo B, Nicholson SA, Arbuthnot PB. The role of long non-coding RNAs in hepatitis B virus-related hepatocellular carcinoma. Virus Res 2016; 212:103-13. [DOI: 10.1016/j.virusres.2015.07.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/26/2015] [Accepted: 07/28/2015] [Indexed: 02/06/2023]
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20
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Specific GFP-binding artificial proteins (αRep): a new tool for in vitro to live cell applications. Biosci Rep 2015; 35:BSR20150080. [PMID: 26182430 PMCID: PMC4613692 DOI: 10.1042/bsr20150080] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/23/2015] [Indexed: 02/08/2023] Open
Abstract
Artificial proteins, named αRep, binding tightly and specifically to EGFP are described. The structures of αRep–EGFP complexes explain how αRep recognize their cognate partner. Specific αRep can be used for biochemical or live cells experiments. A family of artificial proteins, named αRep, based on a natural family of helical repeat was previously designed. αRep members are efficiently expressed, folded and extremely stable proteins. A large αRep library was constructed creating proteins with a randomized interaction surface. In the present study, we show that the αRep library is an efficient source of tailor-made specific proteins with direct applications in biochemistry and cell biology. From this library, we selected by phage display αRep binders with nanomolar dissociation constants against the GFP. The structures of two independent αRep binders in complex with the GFP target were solved by X-ray crystallography revealing two totally different binding modes. The affinity of the selected αReps for GFP proved sufficient for practically useful applications such as pull-down experiments. αReps are disulfide free proteins and are efficiently and functionally expressed in eukaryotic cells: GFP-specific αReps are clearly sequestrated by their cognate target protein addressed to various cell compartments. These results suggest that αRep proteins with tailor-made specificity can be selected and used in living cells to track, modulate or interfere with intracellular processes.
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21
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Wu Q, Qiao L, Yang J, Zhou Y, Liu Q. Stronger activation of SREBP-1a by nucleus-localized HBx. Biochem Biophys Res Commun 2015; 460:561-5. [PMID: 25800871 DOI: 10.1016/j.bbrc.2015.03.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/12/2015] [Indexed: 12/17/2022]
Abstract
We previously showed that hepatitis B virus (HBV) X protein activates the sterol regulatory element-binding protein-1a (SREBP-1a). Here we examined the role of nuclear localization of HBx in this process. In comparison to the wild-type and cytoplasmic HBx, nuclear HBx had stronger effects on SREBP-1a and fatty acid synthase transcription activation, intracellular lipid accumulation and cell proliferation. Furthermore, nuclear HBx could activate HBV enhancer I/X promoter and was more effective on up-regulating HBV mRNA level in the context of HBV replication than the wild-type HBx, while the cytoplasmic HBx had no effect. Our results demonstrate the functional significance of the nucleus-localized HBx in regulating host lipogenic pathway and HBV replication.
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Affiliation(s)
- Qi Wu
- VIDO-InterVac, Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada
| | - Ling Qiao
- VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Jian Yang
- Drug Discovery Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yan Zhou
- VIDO-InterVac, Veterinary Microbiology, Vaccinology and Immunotherapeutics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Qiang Liu
- VIDO-InterVac, Veterinary Microbiology, Vaccinology and Immunotherapeutics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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22
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Kim MS, Lee DY. Insulin-like growth factor binding protein-3 enhances etoposide-induced cell growth inhibition by suppressing the NF-κB activity in gastric cancer cells. Mol Cell Biochem 2015; 403:107-13. [PMID: 25662950 DOI: 10.1007/s11010-015-2341-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 01/30/2015] [Indexed: 01/20/2023]
Abstract
Nuclear factor-kappaB (NF-κB) is a transcription factor that is activated in various neoplasms, including gastric cancer. Insulin-like growth factor binding protein-3 (IGFBP-3) is a potent tumor suppressor and is significantly suppressed in a variety of cancers. Although IGFBP-3 has been reported to have antiproliferative and proapoptotic effects, the precise mechanisms underlying the action of IGFBP-3 have not been elucidated. In this study, we found an inverse correlation between NF-κB activity and IGFBP-3 expression in patients with gastric cancer. Overexpression of IGFBP-3 resulted in significant inhibition of total and phosphorylated p65 NF-κB and IκB proteins in gastric cancer cells. IGFBP-3 further inhibited the expression of NF-κB-regulated cell adhesion molecules, ICAM-1 and VCAM-1. Finally, the growth inhibition induced by etoposide was significantly enhanced by IGFBP-3 overexpression along with concomitant suppression of NF-κB activity. These findings indicate that IGFBP-3 enhances etoposide-induced cell growth inhibition by blocking the NF-κB signaling pathway in gastric cancer cells. Furthermore, our data suggest that IGFBP-3 could be used as an adjuvant in the treatment of gastric cancer.
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Affiliation(s)
- Min Sun Kim
- Department of Pediatrics, Chonbuk National University Medical School, Chonbuk National University Hospital, 634-18 Keumam-dong, Jeonju, 561-712, Korea
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23
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Aligeti M, Behrens RT, Pocock GM, Schindelin J, Dietz C, Eliceiri KW, Swanson CM, Malim MH, Ahlquist P, Sherer NM. Cooperativity among Rev-associated nuclear export signals regulates HIV-1 gene expression and is a determinant of virus species tropism. J Virol 2014; 88:14207-21. [PMID: 25275125 PMCID: PMC4249125 DOI: 10.1128/jvi.01897-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/23/2014] [Indexed: 01/20/2023] Open
Abstract
UNLABELLED Murine cells exhibit a profound block to HIV-1 virion production that was recently mapped to a species-specific structural attribute of the murine version of the chromosomal region maintenance 1 (mCRM1) nuclear export receptor and rescued by the expression of human CRM1 (hCRM1). In human cells, the HIV-1 Rev protein recruits hCRM1 to intron-containing viral mRNAs encoding the Rev response element (RRE), thereby facilitating viral late gene expression. Here we exploited murine 3T3 fibroblasts as a gain-of-function system to study hCRM1's species-specific role in regulating Rev's effector functions. We show that Rev is rapidly exported from the nucleus by mCRM1 despite only weak contributions to HIV-1's posttranscriptional stages. Indeed, Rev preferentially accumulates in the cytoplasm of murine 3T3 cells with or without hCRM1 expression, in contrast to human HeLa cells, where Rev exhibits striking en masse transitions between the nuclear and cytoplasmic compartments. Efforts to bias Rev's trafficking either into or out of the nucleus revealed that Rev encoding a second CRM1 binding domain (Rev-2xNES) or Rev-dependent viral gag-pol mRNAs bearing tandem RREs (GP-2xRRE), rescue virus particle production in murine cells even in the absence of hCRM1. Combined, these results suggest a model wherein Rev-associated nuclear export signals cooperate to regulate the number or quality of CRM1's interactions with viral Rev/RRE ribonucleoprotein complexes in the nucleus. This mechanism regulates CRM1-dependent viral gene expression and is a determinant of HIV-1's capacity to produce virions in nonhuman cell types. IMPORTANCE Cells derived from mice and other nonhuman species exhibit profound blocks to HIV-1 replication. Here we elucidate a block to HIV-1 gene expression attributable to the murine version of the CRM1 (mCRM1) nuclear export receptor. In human cells, hCRM1 regulates the nuclear export of viral intron-containing mRNAs through the activity of the viral Rev adapter protein that forms a multimeric complex on these mRNAs prior to recruiting hCRM1. We demonstrate that Rev-dependent gene expression is poor in murine cells despite the finding that, surprisingly, the bulk of Rev interacts efficiently with mCRM1 and is rapidly exported from the nucleus. Instead, we map the mCRM1 defect to the apparent inability of this factor to engage Rev multimers in the context of large viral Rev/RNA ribonucleoprotein complexes. These findings shed new light on HIV-1 gene regulation and could inform the development of novel antiviral strategies that target viral gene expression.
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Affiliation(s)
- Mounavya Aligeti
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ryan T Behrens
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ginger M Pocock
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Johannes Schindelin
- Morgridge Institute for Research, Madison, Wisconsin, USA Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christian Dietz
- Department of Computer and Information Science, University of Constance, Constance, Germany
| | - Kevin W Eliceiri
- Morgridge Institute for Research, Madison, Wisconsin, USA Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Chad M Swanson
- Department of Infectious Diseases, King's College London, London, United Kingdom
| | - Michael H Malim
- Department of Infectious Diseases, King's College London, London, United Kingdom
| | - Paul Ahlquist
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA Morgridge Institute for Research, Madison, Wisconsin, USA Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nathan M Sherer
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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24
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Saxena N, Kumar V. The HBx oncoprotein of hepatitis B virus deregulates the cell cycle by promoting the intracellular accumulation and re-compartmentalization of the cellular deubiquitinase USP37. PLoS One 2014; 9:e111256. [PMID: 25347529 PMCID: PMC4210131 DOI: 10.1371/journal.pone.0111256] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/16/2014] [Indexed: 01/25/2023] Open
Abstract
The HBx oncoprotein of hepatitis B Virus has been accredited as one of the protagonists in driving hepatocarcinogenesis. HBx exerts its influence over the cell cycle progression by potentiating the activity of cyclin A/E-CDK2 complex, the Cyclin A partner of which is a well-known target of cellular deubiquitinase USP37. In the present study, we observed the intracellular accumulation of cyclin A and USP37 proteins under the HBx microenvironment. Flow cytometry analysis of the HBx-expressing cells showed deregulation of cell cycle apparently due to the enhanced gene expression and stabilization of USP37 protein and deubiquitination of Cyclin A by USP37. Our co-immunoprecipitation and confocal microscopic studies suggested a direct interaction between USP37 and HBx. This interaction promoted the translocation of USP37 outside the nucleus and prevented its association and ubiquitination by E3 ubiquitin ligases - APC/CDH1 and SCF/β-TrCP. Thus, HBx seems to control the cell cycle progression via the cyclin A-CDK2 complex by regulating the intracellular distribution and stability of deubiquitinase USP37.
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Affiliation(s)
- Nehul Saxena
- Virology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Vijay Kumar
- Virology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
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Feitelson MA, Bonamassa B, Arzumanyan A. The roles of hepatitis B virus-encoded X protein in virus replication and the pathogenesis of chronic liver disease. Expert Opin Ther Targets 2014; 18:293-306. [PMID: 24387282 DOI: 10.1517/14728222.2014.867947] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Hepatitis B virus (HBV) is a major cause of chronic liver disease (CLD) and hepatocellular carcinoma (HCC) worldwide. More than 350 million people are at risk for HCC, and with few treatment options available, therapeutic approaches to targets other than the virus polymerase will be needed. This review suggests that the HBV-encoded X protein, HBx, would be an outstanding target because it contributes to the biology and pathogenesis of HBV in three fundamental ways. AREAS COVERED First, HBx is a trans-activating protein that stimulates virus gene expression and replication, thereby promoting the development and persistence of the carrier state. Second, HBx partially blocks the development of immune responses that would otherwise clear the virus, and protects infected hepatocytes from immune-mediated destruction. Thus, HBx contributes to the development of CLD without virus clearance. Third, HBx alters patterns of host gene expression that make possible the emergence of HCC. The selected literature cited is from the National Library of Medicine (Pubmed and Medline). EXPERT OPINION Understanding the mechanisms, whereby HBx supports virus replication and promotes pathogenesis, suggests that HBx will be an important therapeutic target against both virus replication and CLD aimed at the chemoprevention of HCC.
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Affiliation(s)
- Mark A Feitelson
- Temple University, College of Science and Technology, Department of Biology , Room 409 BioLife Science Building, 1900 N. 12th Street, Philadelphia, PA 19122 , USA +1 215 204 8434 ; +1 215 204 8359 ;
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Ayub A, Ashfaq UA, Haque A. HBV induced HCC: major risk factors from genetic to molecular level. BIOMED RESEARCH INTERNATIONAL 2013; 2013:810461. [PMID: 23991421 PMCID: PMC3749539 DOI: 10.1155/2013/810461] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/09/2013] [Indexed: 12/15/2022]
Abstract
Hepatocellular carcinoma (HCC) is a deadly and emerging disease leading to death in Asian countries. High hepatitis B virus (HBV) load and chronic hepatitis B (CHB) infection increase the risk of developing HCC. HBV is a DNA virus that can integrate DNA into host genome thereby increase the yield of transactivator protein HBxAg that may deregulate many pathways involving in metabolism of cells. Several monogenic and polygenic risk factors are also involved in HCC development. This review summarizes the mechanism involved in HCC development and discusses some promising therapies to make HCC curative.
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Affiliation(s)
- Ambreen Ayub
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad (GCUF), Faisalabad 38000, Pakistan
| | - Usman Ali Ashfaq
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad (GCUF), Faisalabad 38000, Pakistan
| | - Asma Haque
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad (GCUF), Faisalabad 38000, Pakistan
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Martín-Vílchez S, Moreno-Otero R, Sanz-Cameno P. [Effects of hepatitis B virus X protein on chronic hepatitis B pathophysiology]. Med Clin (Barc) 2013; 140:508-13. [PMID: 23245531 DOI: 10.1016/j.medcli.2012.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 08/07/2012] [Accepted: 09/06/2012] [Indexed: 02/07/2023]
Abstract
The infection by hepatitis B virus often promotes chronic liver inflammation which progresses to cirrhosis and hepatocellular carcinoma in a high percentage of patients. The persistent activation of the immune system causes an incessant liver damage, which fosters a disorganized stimulation of tissue repair and remodelling phenomena. In turn, the viral protein X (HBx) is essential for virus replication and therefore for the maintenance of chronic infection. However, the important oncogenic potential of HBx seems to reside, on one hand, in its ability to integrate into cellular DNA and, additionally, in the transactivation of different cellular signaling pathways involved in cell growth regulation, apoptosis and DNA repair. HBx also interacts with proteasome subunits and notably affects mitochondrial electric potential, thus altering cellular calcium homeostasis. Finally, this review discusses the pathogenic role of HBx in the progression of chronic hepatitis B through its effects on angiogenic, fibrogenic and oncogenic processes.
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Affiliation(s)
- Samuel Martín-Vílchez
- Servicio de Aparato Digestivo, Hospital Universitario La Princesa, Universidad Autónoma de Madrid, Madrid, España
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28
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Sumiyoshi S, Kobayashi Y, Kawamura K, Kawata K, Nakamura H. Differential expression of hepatic apurinic/apyrimidinic endonuclease 1, a DNA repair enzyme, in chronic hepatitis. World J Hepatol 2013; 5:206-213. [PMID: 23671725 PMCID: PMC3648652 DOI: 10.4254/wjh.v5.i4.206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/14/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine hepatic expression of apurinic/apyrimidinic endonuclease 1 (APE-1) and 8-hydroxydeoxyguanosine (8-OHdG) in patients with chronic hepatitis B and C.
METHODS: Liver biopsies were obtained from 27 patients with chronic hepatitis B virus (HBV), 30 with chronic hepatitis C virus (HCV), 6 with autoimmune hepatitis (AIH), and 6 with primary biliary cirrhosis (PBC). Normal liver tissue was obtained from surgical resection specimens of four patients. Hepatic APE-1 protein and mRNA expression were assayed by Western blot and by real-time polymerase chain reaction, respectively. Hepatocellular APE-1 and 8-OHdG expression were determined by immunohistochemistry.
RESULTS: The staining intensity of hepatocellular nuclear APE-1 was lower in the HBV group than in the other groups (P < 0.05). Hepatic APE-1 protein levels were reduced in the HBV group relative to the other groups. Hepatic APE-1 mRNA levels were also lower in the HBV group. The proportion of hepatocytes with 8-OHdG-positive nuclei was increased in the HCV, AIH and PBC groups (P < 0.05), but not in the HBV group. Hepatocellular nuclear APE-1 levels were positively correlated with hepatocellular 8-OHdG levels in both the HBV and HCV groups (HBV, r = 0.34, P < 0.05; HCV, r = 0.54, P < 0.01).
CONCLUSION: An imbalance between oxidative DNA damage and APE-1 expression may contribute to hepatocarcinogenesis in chronic viral hepatitis.
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30
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Zhang KJ, Wang M. Potential effects of CRM1 inhibition in mantle cell lymphoma. Chin J Cancer Res 2013; 24:374-87. [PMID: 23357869 DOI: 10.3978/j.issn.1000-9604.2012.09.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 02/08/2012] [Indexed: 12/14/2022] Open
Abstract
Mantle cell lymphoma (MCL) is an aggressive histotype of B-cell non-Hodgkin lymphoma. The disease has no known cure, which prompts the urgent need for novel therapeutic agents. Chromosomal region maintenance 1 (CRM1) may play a role in human neoplasia and serve as a novel target of cancer treatment. This study summarizes MCL pathogenesis and determines the involvement of CRM1 in the regulation of several vital signaling pathways contributing to MCL pathogenesis, including the pathways of cell cycle progression, DNA damage response, phosphoinositide kinase-3, nuclear factor-κB activation, and chromosomal stability. A preclinical study is also presented to compare the CRM1 status in MCL cell lines and primary MCL cells with normal B cells, as well as the therapeutic efficiency of CRM1 inhibition in MCL in vitro and in vivo, which make these agents potential targets of novel MCL treatments.
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Affiliation(s)
- Ke-Jie Zhang
- Department of Hematology, Zhongshan Hospital, Xiamen University, Xiamen 361004, China; ; Department of Lymphoma and Myeloma, The University of Texas MD Anderson Cancer Center, Houston 77030, USA
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31
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Reply to “Nuclear Export Signal and Immunodominant CD8
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T Cell Epitope in Influenza A Virus Matrix Protein 1”. J Virol 2012. [DOI: 10.1128/jvi.01245-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ma J, Sun T, Park S, Shen G, Liu J. The role of hepatitis B virus X protein is related to its differential intracellular localization. Acta Biochim Biophys Sin (Shanghai) 2011; 43:583-8. [PMID: 21693548 DOI: 10.1093/abbs/gmr048] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection has been strongly associated with hepatocellular carcinoma. HBV encodes an oncogenic hepatitis B virus X protein (HBx), which is a multifunctional regulator that modulates signal transduction, transcription, cell cycle progress, protein degradation, apoptosis, and genetic stability through direct and indirect interaction with host factors. The subcellular localization of HBx is primarily cytoplasmic, with a small fraction in the nucleus. In addition, high levels of HBx expression lead to an abnormal mitochondrial distribution. The dynamic distribution of HBx could be important to the multiple functions of HBx at different stages of the HBV life cycle. This short review presents an overview of the differential roles of HBx as a function of its intracellular localization.
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Affiliation(s)
- Jingwei Ma
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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33
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Martin-Vilchez S, Lara-Pezzi E, Trapero-Marugán M, Moreno-Otero R, Sanz-Cameno P. The molecular and pathophysiological implications of hepatitis B X antigen in chronic hepatitis B virus infection. Rev Med Virol 2011; 21:315-29. [PMID: 21755567 DOI: 10.1002/rmv.699] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/23/2011] [Accepted: 05/26/2011] [Indexed: 12/16/2022]
Abstract
Hepatitis B virus is considered one of the most significant environmental carcinogens in humans. Because the mechanisms of HBV replication and the development of hepatocellular carcinoma (HCC) are partially known, HBV-associated pathogenesis remains a challenge to increase its understanding. Evidence suggests that the regulatory protein hepatitis B virus X (HBx) mediates the establishment and maintenance of the chronic carrier state. HBx is a multifunctional and potentially oncogenic protein that is conserved among mammalian hepadnaviruses; it is produced very early after infection and throughout the chronic phase. HBx exerts its effects by interacting with cellular proteins and activating various signaling pathways. HBx stimulates the transcription of genes that regulate cell growth, apoptosis, and DNA repair. It also interacts with proteasome subunits and affects mitochondrial stability. Moreover, HBx participates in processes that are associated with the progression of chronic liver disease, including angiogenesis and fibrosis. This review discusses the function of HBx in the life cycle of HBV and its contribution to the pathogenesis of HCC.
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Affiliation(s)
- Samuel Martin-Vilchez
- CIBERehd, ISCIII, Madrid, Spain; Servicio Digestivo, Hospital Universitario "La Princesa" and Instituto de Investigación Biomédica "La Princesa", Madrid, Spain
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Nikitin PA, Luftig MA. At a crossroads: human DNA tumor viruses and the host DNA damage response. Future Virol 2011; 6:813-830. [PMID: 21927617 DOI: 10.2217/fvl.11.55] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human DNA tumor viruses induce host cell proliferation in order to establish the necessary cellular milieu to replicate viral DNA. The consequence of such viral-programmed induction of proliferation coupled with the introduction of foreign replicating DNA structures makes these viruses particularly sensitive to the host DNA damage response machinery. In fact, sensors of DNA damage are often activated and modulated by DNA tumor viruses in both latent and lytic infection. This article focuses on the role of the DNA damage response during the life cycle of human DNA tumor viruses, with a particular emphasis on recent advances in our understanding of the role of the DNA damage response in EBV, Kaposi's sarcoma-associated herpesvirus and human papillomavirus infection.
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Affiliation(s)
- Pavel A Nikitin
- Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC, 27708 USA
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35
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Han J, Jogie-Brahim S, Harada A, Oh Y. Insulin-like growth factor-binding protein-3 suppresses tumor growth via activation of caspase-dependent apoptosis and cross-talk with NF-κB signaling. Cancer Lett 2011; 307:200-10. [PMID: 21536375 DOI: 10.1016/j.canlet.2011.04.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 03/31/2011] [Accepted: 04/07/2011] [Indexed: 12/22/2022]
Abstract
Nuclear factor-kappaB (NF-κB) is constitutively activated in a variety of human cancers including prostate cancer and involved in tumorigenesis, tumor progression and chemo-resistance. Insulin-like growth factor-binding protein-3 (IGFBP-3) is a potent tumor suppressor and is significantly suppressed in a variety of cancers. Diverse biological effects of IGFBP-3 have been reported to be both dependent and independent of the IGF/IGF-I receptor (IGF-IR) axis. The precise underlying mechanisms of IGF/IGF-IR-independent, antiproliferative actions of IGFBP-3 are yet to be elucidated. We found an inverse correlation between NF-κB activity and IGFBP-3 expression during prostate cancer progression using an in vitro prostate cancer progression model. Restoration of IGFBP-3 resulted in significant inhibition of constitutively elevated NF-κB activity in prostate cancer cells. IGFBP-3 further inhibited the expression of NF-κB-regulated angiogenic factors such as VEGF and IL-8, and cell adhesion molecules, ICAM-1 and VCAM-1. This inhibitory action of IGFBP-3 was IGF/IGF-IR-independent since IGFBP-3 mutant devoid of IGF binding affinity had a similar inhibitory effect. We identified that IGFBP-3 degrades the key NF-κB regulatory molecules-IκBα and p65-NF-κB proteins through activation of caspase-8 and -3/-7, thereby inhibiting elevated NF-κB activity in prostate cancer. Finally intratumoral administration of IGFBP-3 resulted in significant tumor suppression as well as sensitization of antitumor effect of doxorubicin. Our findings indicate that IGFBP-3 exerts antitumor effects via IGF-independent mechanisms which involve activation of caspase-dependent apoptosis and cross-talk with NF-κB signaling. The use of IGFBP-3 as a cancer therapeutic with this distinctive suppression mechanism may offer alternate means to treat chemotherapy resistant tumors.
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Affiliation(s)
- Jinfeng Han
- Department of Pathology, Medical College of Virginia Campus, Virginia Commonwealth University, 1101 East Marshall Street, Richmond, VA 23298-0662, USA
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36
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Lee YC, Jogie-Brahim S, Lee DY, Han J, Harada A, Murphy LJ, Oh Y. Insulin-like growth factor-binding protein-3 (IGFBP-3) blocks the effects of asthma by negatively regulating NF-κB signaling through IGFBP-3R-mediated activation of caspases. J Biol Chem 2011; 286:17898-909. [PMID: 21383009 DOI: 10.1074/jbc.m111.231035] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Insulin-like growth factor-binding protein-3 (IGFBP-3) is a multifunctional protein known for modulating mitogenic and metabolic actions of IGFs as well as exerting a variety of biological actions not involving IGFs. Here, we show that IGFBP-3 blocks specific physiological consequences of asthma in an IGF-independent manner in vitro and in vivo. IGFBP-3 treatment effectively reduced all physiological manifestations of asthma examined in vivo (airway hyper-responsiveness, cellular and pathological changes in bronchoalveolar lavage fluid and lung tissue, and expression of numerous proinflammatory molecules). These unique IGFBP-3 effects were further confirmed in IGFBP-3-transgenic mice, thus strengthening the notion of IGFBP-3 actions within the respiratory system. Using human epithelial cells, we demonstrated the following: 1) IGFBP-3 blocks TNF-α-induced expression of proinflammatory molecules; 2) IGFBP-3 attenuates the TNF-α-induced migratory response of eosinophils; and 3) IGFBP-3 negatively regulates TNF-α-induced expression of the key NF-κB regulatory molecules IκBα and p65-NF-κB at the post-translational level. We identified that IGFBP-3 degrades IκBα and p65-NF-κB proteins through IGFBP-3 receptor (IGFBP-3R)-mediated activation of caspases thereby inhibiting TNF-α-induced activation of NF-κB signaling cascades. This unique IGFBP-3/IGFBP-3R action was further confirmed by demonstrating complete inhibition of IGFBP-3 action in the presence of caspase inhibitors as well as IGFBP-3R siRNAs. Non-IGF-binding IGFBP-3 mutants further proved the IGF-independent action of IGFBP-3. Our findings indicate that IGFBP-3 inhibits airway inflammation and hyper-responsiveness via an IGF-independent mechanism that involves activation of IGFBP-3R signaling and cross-talk with NF-κB signaling. The IGFBP-3/IGFBP-3R system therefore plays a pivotal role in the pathogenesis of asthma and can serve as a newly identified potential therapeutic target for this debilitating disease.
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Affiliation(s)
- Yong-Chul Lee
- Department of Internal Medicine, School of Medicine, Chonbuk National University, Jeonju 56-182, South Korea
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Lu B, Guo H, Zhao J, Wang C, Wu G, Pang M, Tong X, Bu F, Liang A, Hou S, Fan X, Dai J, Wang H, Guo Y. Increased expression of iASPP, regulated by hepatitis B virus X protein-mediated NF-κB activation, in hepatocellular carcinoma. Gastroenterology 2010; 139:2183-2194.e5. [PMID: 20600029 DOI: 10.1053/j.gastro.2010.06.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Revised: 05/27/2010] [Accepted: 06/10/2010] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS iASPP is an inhibitory member of the ankyrin-repeat-, SH3-domain- and proline-rich-region-containing protein (ASPP) family; iASPP expression is up-regulated in different human tumor types. We explored the molecular mechanism increased expression of iASPP and its role in hepatocellular carcinoma (HCC). METHODS iASPP expression levels in human liver samples and cell lines were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor-κB (NF-κB). Effects on tumor growth were characterized with MTS, soft agar colony formation, and flow cytometry analyses. Tumorigenicity of cells was studied in nude mice. RESULTS Compared with normal liver cells or tissues, iASPP was expressed at significantly higher levels in HCC cell lines (9/14) and liver samples from patients with HCC, cirrhosis, or hepatitis B virus infection. Increased expression of iASPP was significantly associated with time to recurrence and survival time of patients with HCC. NF-κB activation increased the expression of iASPP through p65/p50 binding to a putative NF-κB-binding site in the iASPP promoter; hepatitis B virus X gene product might up-regulate expression of iASPP. Transgenic expression of iASPP promoted tumor cell proliferation and resistance to chemotherapeutic drugs in vitro and in vivo. CONCLUSIONS iASPP is up-regulated in HCC; it is a direct transcription target of NF-κB. Increased iASPP expression contributes to tumor progression by proliferative and antiapoptotic effects. iASPP might be developed as an HCC therapeutic target or to sensitize cancer cells to chemotherapeutic drugs; it might also be used as a prognostic factor.
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Affiliation(s)
- Bin Lu
- International Joint Cancer Institute, The Second Military Medical University, Shanghai, China
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Yasunaga J, Jeang KT. Viral transformation and aneuploidy. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:733-740. [PMID: 19326462 PMCID: PMC2760603 DOI: 10.1002/em.20480] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Human tumor viruses are associated with a variety of human malignancies, and it is estimated that 15% of all human cancers have a viral etiology. An abnormality in chromosomal ploidy or aneuploidy is a hallmark of cancers. In normal cells, euploidy is governed by several factors including an intact spindle assembly checkpoint, accurate centrosome duplication, and proper cytokinesis. Viral oncoproteins are suggested to perturb the cellular machineries for chromosomal segregation creating aneuploidy which can lead to the malignant transformation of infected cells. Here, we review in brief some of the mechanisms used by viruses that can cause cellular aneuploidy.
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Affiliation(s)
- Junichiro Yasunaga
- Molecular Virology Section, Laboratory of Molecular Microbiology, The National Institute of Allergy and Infectious Diseases/NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA
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Matsuda Y, Ichida T. Impact of hepatitis B virus X protein on the DNA damage response during hepatocarcinogenesis. Med Mol Morphol 2009; 42:138-42. [PMID: 19784739 DOI: 10.1007/s00795-009-0457-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 06/04/2009] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide. The main HCC-associated diseases are chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV), and HBV-associated HCC is still prevalent in Asia. Many studies have suggested that HBV X protein (HBX), which is the most common ORF integrated into the host genome, plays a crucial role in hepatocarcinogenesis. However, the accumulated evidence regarding HBX-mediated signaling pathways is not concordant, and it is difficult to understand the mechanistic nature of HBX-associated hepatocarcinogenesis. For example, HBX was reported to inactivate the early responses to DNA damage via p53-dependent and -independent pathways by interacting with several DNA damage-binding proteins and was also reported to sensitize cells to p53-mediated apoptosis via ataxia-telangiectasia and Rad3-related (ATR)-dependent signaling. HBX also interferes with the centrosome replication process, resulting in rearrangement of chromosomes with micronuclei. Moreover, HBX was found to sensitize protein kinases such as Ras/Raf/mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), stress-activated protein kinase/NH2-terminal-Jun kinase (SAPK/JNK), protein kinase B (PKB/Akt), and Janus kinase/STAT (JAK/STAT), indicating that a variety of signaling pathways may be activated by HBX. In this review, we focus on the roles of HBX in DNA damage repair during HCC development, with a view to achieving a better understanding of the significance of HBX in the early steps of hepatocarcinogenesis.
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Affiliation(s)
- Yasunobu Matsuda
- Department of Medical Technology, Niigata University Graduate School of Health Sciences, Niigata, 951-8518, Japan.
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40
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Keasler VV, Hodgson AJ, Madden CR, Slagle BL. Hepatitis B virus HBx protein localized to the nucleus restores HBx-deficient virus replication in HepG2 cells and in vivo in hydrodynamically-injected mice. Virology 2009; 390:122-9. [PMID: 19464721 DOI: 10.1016/j.virol.2009.05.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2009] [Revised: 04/10/2009] [Accepted: 05/02/2009] [Indexed: 12/12/2022]
Abstract
Identifying the requirements for the regulatory HBx protein in hepatitis B virus (HBV) replication is an important goal. A plasmid-based HBV replication assay was used to evaluate whether HBx subcellular localization influences its ability to promote virus replication, as measured by real time PCR quantitation of viral capsid-associated DNA. HBx targeted to the nucleus by a nuclear localization signal (NLS-HBx) was able to restore HBx-deficient HBV replication, while HBx containing a nuclear export signal (NES-HBx) was not. Both NLS-HBx and NES-HBx were expressed at similar levels (by immunoprecipitation and Western blotting), and proper localization of the signal sequence-tagged proteins was confirmed by deconvolution microscopy using HBx, NLS-HBx, and NES-HBx proteins fused to GFP. Importantly, these findings were confirmed in vivo by hydrodynamic injection into mice. Our results demonstrate that in these HBV replication assays, at least one function of HBx requires its localization to the nucleus.
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Affiliation(s)
- Victor V Keasler
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030-3411, USA
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41
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Molecular determinants for subcellular localization of the severe acute respiratory syndrome coronavirus open reading frame 3b protein. J Virol 2009; 83:6631-40. [PMID: 19403678 DOI: 10.1128/jvi.00367-09] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viruses such as hepatitis C and the severe acute respiratory syndrome coronavirus (SARS-CoV) encode proteins that are distributed between mitochondria and the nucleus, but little is known about the factors that control partitioning between these sites. SARS-CoV encodes a unique accessory gene called open reading frame (ORF) 3b that, like other unique accessory genes in SARS-CoV, likely contributes to viral pathogenicity. The ORF 3b protein is 154 amino acids and is predicted to express from the second ORF in subgenomic RNA3. In this report, we have characterized the molecular components that regulate intracellular localization of the ORF 3b protein. We demonstrate unique shuttling behavior of ORF 3b, whereby the protein initially accumulates in the nucleus and subsequently translocates to mitochondria. Following nuclear localization, ORF 3b traffics to the outer membrane of mitochondria via a predicted amphipathic alpha-helix. Additionally, ORF 3b contains a consensus nuclear export sequence, and we demonstrate that nuclear export and thus mitochondrial translocation are dependent on a leptomycin B-sensitive nuclear export mechanism. We further show that ORF 3b inhibits induction of type I interferon induced by retinoic acid-induced gene 1 and the mitochondrial antiviral signaling protein. Our observations provide insights into the cellular localization of ORF 3b that may enhance our understanding of the mechanisms by which ORF 3b contributes to SARS-CoV pathogenesis. The findings reported here reveal that for multilocalized proteins, consideration of the spatiotemporal distribution may be crucial for understanding viral protein behavior and function.
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Han Z. Recent progress in genomic [corrected] research of liver cancer. ACTA ACUST UNITED AC 2009; 52:24-30. [PMID: 19152081 DOI: 10.1007/s11427-009-0010-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 01/12/2023]
Abstract
Along the course of occurrence and development of liver cancer, the corresponding somatic cells accumulate some important genetic variations. These variations may be divided into two categories. For the genetic changes closely related to etiology of liver cancer, the well-known cases include insertion and integration of the hepatitis B virus (HBV) DNA after infection, and mutations at site 249 of the tumor suppressor gene p53 induced by exposure to aflatoxin B1. The secondary genetic changes include amplification and deletion of certain chromosome regions, mutations in p53 at the sites other than 249, as well as the mutational activation of the Wnt/beta-catenin signal pathway. The tumor cells with these genetic variations may gradually become the dominant clones under evolutionary selection. Besides, identification of genetic susceptible against risk of liver malignancy is also an important aspect of research in this field.
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Affiliation(s)
- ZeGuang Han
- Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, 201203, China.
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Li SK, Ho SF, Tsui KW, Fung KP, Waye MYM. Identification of functionally important amino acid residues in the mitochondria targeting sequence of hepatitis B virus X protein. Virology 2008; 381:81-8. [PMID: 18805561 DOI: 10.1016/j.virol.2008.07.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/07/2008] [Accepted: 07/28/2008] [Indexed: 01/26/2023]
Abstract
Chronic hepatitis B virus (HBV) infection has been strongly associated with hepatocellular carcinoma (HCC) and the X protein (HBx) is thought to mediate the cellular changes associated with carcinogenesis. Recently, isolation of the hepatitis B virus integrants from HCC tissue by others have established the fact that the X gene is often truncated at its C-terminus. Expression of the GFP fusion proteins of HBx and its truncation mutants with a GFP tag in human liver cell-lines in this study revealed that the C-terminus of HBx is indispensable for its specific localization in the mitochondria. A crucial region of seven amino acids at the C-terminus has been mapped out in which the cysteine residue at position 115 serves as the most important residue for the subcellular localization. When cysteine 115 of HBx is mutated to alanine the mitochondria targeting property of HBx is abrogated.
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Affiliation(s)
- Sai Kam Li
- Croucher Laboratory for Human Genomics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, S.A.R., China
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Feitelson MA, Reis HMGPV, Pan J, Clayton M, Sun B, Satiroglu-Tufan NL, Lian Z. HBV X protein: elucidating a role in oncogenesis. Future Virol 2008. [DOI: 10.2217/17460794.3.5.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chronic HBV infection is associated with the development of hepatocellular carcinoma (HCC). HBV contributes to tumorigenesis by encoding hepatitis B x antigen (HBxAg), which is a trans-regulatory protein that appears to contribute to HCC by altering patterns of host gene expression. In this review, recent data is presented that outlines some of the putative mechanisms whereby HBxAg contributes to HCC. With the development of animal models of HBxAg-mediated HCC, the relevance and temporal order of putative steps in this process can now be dissected to elucidate what is rate limiting and when. This will have a profound impact on the design of novel and specific therapeutics for HCC.
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Affiliation(s)
- Mark A Feitelson
- Department of Biology, College of Science & Technology, Temple University, PA 19122, USA. and, Center for Biotechnology, College of Science & Technology, Temple University, PA 19122, USA
| | - Helena MGPV Reis
- MIT Portugal Program, Av. Antonio Jose de Almeida, 12 1000–043 Lisboa, Portugal
| | - Jingbo Pan
- Department of Pathology, Anatomy & Cell Biology, Thomas Jefferson University, PA 19107, USA
| | - Marcy Clayton
- Department of Biology, College of Science & Technology, Temple University, PA 19122, USA
| | - Bill Sun
- Department of Biology, College of Science & Technology, Temple University, PA 19122, USA
| | - N Lale Satiroglu-Tufan
- Department of Medical Biology, Pamukkale University School of Medicine, Kinikli Kampusu Morfoloji Binasi, 20020 Denizli, Turkey
| | - Zhaorui Lian
- Department of Biology, College of Science & Technology, Temple University, PA 19122, USA
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Feitelson MA, Lee J. Hepatitis B virus integration, fragile sites, and hepatocarcinogenesis. Cancer Lett 2006; 252:157-70. [PMID: 17188425 DOI: 10.1016/j.canlet.2006.11.010] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 11/08/2006] [Accepted: 11/13/2006] [Indexed: 12/31/2022]
Abstract
Chronic liver disease associated with long term hepatitis B virus (HBV) infection contributes importantly to the development of hepatocellular carcinoma (HCC). A salient feature of these chronic infections is the integration of subgenomic HBV DNA fragments into many different locations within the host DNA, suggesting that integration is random. Although this may promote genetic instability during liver regeneration which accompanies a bout of chronic liver disease, the actual role of integrated HBV DNA in hepatocarcinogenesis is uncertain. Importantly, most integration events retain the HBV open reading frame encoding the HBx antigen (HBxAg), which is the virus contribution to HCC. In addition, many integration events reported in the literature occur near or within fragile sites or other cancer associated regions of the human genome that are prone to instability in tumor development and progression. Genetic instability associated with integration potentially alters the expression of oncogenes, tumor suppressor genes, and microRNAs (miRNAs) that may contribute importantly to tumorigenesis. If so, then selected integration events may alter pathways that are rate limiting in hepatocarcinogenesis, thereby providing targets with diagnostic/prognostic potential and for therapeutic intervention.
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Affiliation(s)
- Mark A Feitelson
- Department of Pathology, Anatomy and Cell Biology, Kimmel Cancer Center, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA.
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Tang H, Oishi N, Kaneko S, Murakami S. Molecular functions and biological roles of hepatitis B virus x protein. Cancer Sci 2006; 97:977-83. [PMID: 16984372 PMCID: PMC11159107 DOI: 10.1111/j.1349-7006.2006.00299.x] [Citation(s) in RCA: 238] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chronic infection of hepatitis B virus (HBV) is one of the major causes of hepatocellular carcinoma (HCC) in the world. Hepatitis B virus X protein (HBx) has been long suspected to be involved in hepatocarcinogenesis, although its oncogenic role remains controversial. HBx is a multifunctional regulator that modulates transcription, signal transduction, cell cycle progress, protein degradation pathways, apoptosis, and genetic stability by directly or indirectly interacting with host factors. This review focuses on the biological roles of HBx in HBV replication and cellular transformation in terms of the molecular functions of HBx. Using the transient HBV replication assay, ectopically expressed HBx could stimulate HBV transcription and replication with the X-defective replicon to the level of those with the wild one. The transcription coactivation is mainly contributing to the stimulatory role of HBx on HBV replication although the other functions may affect HBV replication. Effect of HBx on cellular transformation remains controversial and was never addressed with human primary or immortal cells. Using the human immortalized primary cells, HBx was found to retain the ability to overcome active oncogene RAS-induced senescence that requires full-length HBx. At least two functions of HBx, the coactivation function and the ability to overcome oncogene-induced senescence, may be cooperatively involved in HBV-related hepatocarcinogenesis.
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Affiliation(s)
- Hong Tang
- Division of Biotherapy of Infectious Diseases, Key Laboratory of Biotherapy of Human Diseases, Ministry of Education, Chengdu, Sichuan, China
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Pumfery A, de la Fuente C, Kashanchi F. HTLV-1 Tax: centrosome amplification and cancer. Retrovirology 2006; 3:50. [PMID: 16899128 PMCID: PMC1555608 DOI: 10.1186/1742-4690-3-50] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 08/09/2006] [Indexed: 11/16/2022] Open
Abstract
During interphase, each cell contains a single centrosome that acts as a microtubule organizing center for cellular functions in interphase and in mitosis. Centrosome amplification during the S phase of the cell cycle is a tightly regulated process to ensure that each daughter cell receives the proper complement of the genome. The controls that ensure that centrosomes are duplicated exactly once in the cell cycle are not well understood. In solid tumors and hematological malignancies, centrosome abnormalities resulting in aneuploidy is observed in the majority of cancers. These phenotypes are also observed in cancers induced by viruses, including adult T cell lymphoma which is caused by the human T cell lymphotrophic virus Type 1 (HTLV-1). Several reports have indicated that the HTLV-1 transactivator, Tax, is directly responsible for the centrosomal abnormalities observed in ATL cells. A recent paper in Nature Cell Biology by Ching et al. has shed some new light into how Tax may be inducing centrosome abnormalities. The authors demonstrated that 30% of ATL cells contained more than two centrosomes and expression of Tax alone induced supernumerary centrosomes. A cellular coiled-coil protein, Tax1BP2, was shown to interact with Tax and disruption of this interaction led to failure of Tax to induce centrosome amplification. Additionally, down-regulation of Tax1BP2 led to centrosome amplification. These results suggest that Tax1BP2 may be an important block to centrosome re-duplication that is observed in normal cells. Presently, a specific cellular protein that prevents centrosome re-duplication has not been identified. This paper has provided further insight into how Tax induces centrosome abnormalities that lead to ATL. Lastly, additional work on Tax1BP2 will also provide insight into how the cell suppresses centrosome re-duplication during the cell cycle and the role that Tax1BP2 plays in this important cellular pathway.
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Affiliation(s)
- Anne Pumfery
- Seton Hall University, Department of Biology, South Orange, NJ 07079, USA
| | - Cynthia de la Fuente
- The Rockefeller University, Laboratory of Virology and Infectious Disease, New York, NY 10021, USA
| | - Fatah Kashanchi
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
- The Institute for Genomic Research, Rockville, Maryland 20850, USA
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Bonamy GM, Allison LA. Oncogenic conversion of the thyroid hormone receptor by altered nuclear transport. NUCLEAR RECEPTOR SIGNALING 2006; 4:e008. [PMID: 16741566 PMCID: PMC1472669 DOI: 10.1621/nrs.04008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Accepted: 02/16/2006] [Indexed: 01/14/2023]
Abstract
Nuclear receptors (NRs) are transcription factors whose activity is modulated by ligand binding. These receptors are at the core of complex signaling pathways and act as integrators of many cellular signals. In the last decade our understanding of NRs has greatly evolved. In particular, regulation of NR subcellular dynamics has emerged as central to their activity. Research on the subcellular distribution of the thyroid hormone receptor (TR) has revealed new dimensions in the complexity of NR regulation, and points to the possibility that NR mislocalization plays a key role in oncogenesis. For many years, TR was thought to reside exclusively in the nucleus. It is now known that TR is a dynamic protein that shuttles between the nucleus and cytoplasm. TR is localized to the nucleus in a phosphorylated form, suggesting that compartment-specific phosphorylation mediates cross-talk between multiple cell signaling pathways. The oncoprotein v-ErbA, a viral-derived dominant negative variant of TR is actively exported to the cytoplasm by the CRM1 export receptor. Strikingly, the oncoprotein causes mislocalization of cellular TR and some of its coactivators by direct interaction. Here, we offer some perspectives on the role of subcellular trafficking in the oncogenic conversion of TR, and propose a new model for oncoprotein dominant negative activity.
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Shinmura K, Tarapore P, Tokuyama Y, George KR, Fukasawa K. Characterization of centrosomal association of nucleophosmin/B23 linked to Crm1 activity. FEBS Lett 2005; 579:6621-34. [PMID: 16297385 DOI: 10.1016/j.febslet.2005.10.057] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 10/20/2005] [Accepted: 10/28/2005] [Indexed: 11/24/2022]
Abstract
Nucleophosmin (NPM)/B23 is a multifunctional protein, involving in a wide variety of basic cellular processes, including ribosome assembly, DNA duplication, nucleocytoplasmic trafficking, and centrosome duplication. It has previously been shown that NPM/B23 localizes to centrosomes, and dissociate from centrosomes upon phosphorylation by Cdk2/cyclin E. However, detail characterization of centrosomal association of NPM/B23 has been hampered by the lack of appropriate antibodies that efficiently detects centrosomally localized NPM/B23, as well as by apparent loss of natural behavior of NPM/B23 when tagged with fluorescent proteins. Here, by the use of newly generated anti-NPM/B23 antibody, we conducted a careful analysis of centrosomal localization of NPM/B23. We found that NPM/B23 localizes between the paired centrioles of unduplicated centrosomes, suggesting the role of NPM/B23 in the centriole pairing. Upon initiation of centrosome duplication, some NPM/B23 proteins remain at mother centrioles of the parental centriole pairs. We further found that inhibition of Crm1 nuclear export receptor results in both accumulation of cyclin E at centrosomes and efficient dissociation of NPM/B23 from centrosomes.
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Affiliation(s)
- Kazuya Shinmura
- Department of Cell Biology, University of Cincinnati College of Medicine, P.O. Box 670521 (3125 Eden Avenue), Cincinnati, OH 45267-0521, United States
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