1
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Yun C, Kim SH, Kwon D, Byun MR, Chung KW, Lee J, Jung YS. Doxorubicin Attenuates Free Fatty Acid-Induced Lipid Accumulation via Stimulation of p53 in HepG2 Cells. Biomol Ther (Seoul) 2024; 32:94-103. [PMID: 38148555 PMCID: PMC10762281 DOI: 10.4062/biomolther.2023.200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 12/28/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive accumulation of fat in the liver, and there is a global increase in its incidence owing to changes in lifestyle and diet. Recent findings suggest that p53 is involved in the development of non-alcoholic fatty liver disease; however, the association between p53 expression and the disease remains unclear. Doxorubicin, an anticancer agent, increases the expression of p53. Therefore, this study aimed to investigate the role of doxorubicin-induced p53 upregulation in free fatty acid (FFA)-induced intracellular lipid accumulation. HepG2 cells were pretreated with 0.5 μg/mL of doxorubicin for 12 h, followed by treatment with FFA (0.5 mM) for 24 h to induce steatosis. Doxorubicin pretreatment upregulated p53 expression and downregulated the expression of endoplasmic reticulum stress- and lipid synthesis-associated genes in the FFA -treated HepG2 cells. Additionally, doxorubicin treatment upregulated the expression of AMP-activated protein kinase, a key modulator of lipid metabolism. Notably, siRNA-targeted p53 knockdown reversed the effects of doxorubicin in HepG2 cells. Moreover, doxorubicin treatment suppressed FFA -induced lipid accumulation in HepG2 spheroids. Conclusively, these results suggest that doxorubicin possesses potential application for the regulation of lipid metabolism by enhance the expression of p53 an in vitro NAFLD model.
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Affiliation(s)
- Chawon Yun
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan 46241, Republic of Korea
| | - Sou Hyun Kim
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan 46241, Republic of Korea
| | - Doyoung Kwon
- College of Pharmacy, Jeju Research Institute of Pharmaceutical Sciences, Jeju National University, Jeju 63243, Republic of Korea
| | - Mi Ran Byun
- College of Pharmacy, Daegu Catholic University, Gyeongsan 38430, Republic of Korea
| | - Ki Wung Chung
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan 46241, Republic of Korea
| | - Jaewon Lee
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan 46241, Republic of Korea
| | - Young-Suk Jung
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan 46241, Republic of Korea
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2
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Singh Y, Subbarao N, Jaimini A, Hathaway QA, Kunovac A, Erickson B, Swarup V, Singh HN. Genome-wide expression reveals potential biomarkers in breast cancer bone metastasis. J Integr Bioinform 2022; 19:jib-2021-0041. [PMID: 35388653 PMCID: PMC9521824 DOI: 10.1515/jib-2021-0041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/08/2022] [Indexed: 11/23/2022] Open
Abstract
Breast cancer metastases are most commonly found in bone, an indication of poor prognosis. Pathway-based biomarkers identification may help elucidate the cellular signature of breast cancer metastasis in bone, further characterizing the etiology and promoting new therapeutic approaches. We extracted gene expression profiles from mouse macrophages from the GEO dataset, GSE152795 using the GEO2R webtool. The differentially expressed genes (DEGs) were filtered by log2 fold-change with threshold 1.5 (FDR < 0.05). STRING database and Enrichr were used for GO-term analysis, miRNA and TF analysis associated with DEGs. Autodock Vienna was exploited to investigate interaction of anti-cancer drugs, Actinomycin-D and Adriamycin. Sensitivity and specificity of DEGs was assessed using receiver operating characteristic (ROC) analyses. A total of 61 DEGs, included 27 down-regulated and 34 up-regulated, were found to be significant in breast cancer bone metastasis. Major DEGs were associated with lipid metabolism and immunological response of tumor tissue. Crucial DEGs, Bcl3, ADGRG7, FABP4, VCAN, and IRF4 were regulated by miRNAs, miR-497, miR-574, miR-138 and TFs, CCDN1, STAT6, IRF8. Docking analysis showed that these genes possessed strong binding with the drugs. ROC analysis demonstrated Bcl3 is specific to metastasis. DEGs Bcl3, ADGRG7, FABP4, IRF4, their regulating miRNAs and TFs have strong impact on proliferation and metastasis of breast cancer in bone tissues. In conclusion, present study revealed that DEGs are directly involved in of breast tumor metastasis in bone tissues. Identified genes, miRNAs, and TFs can be possible drug targets that may be used for the therapeutics. However, further experimental validation is necessary.
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Affiliation(s)
- Yashbir Singh
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Abhinav Jaimini
- Divisions of PET Imaging, MIRC, Institute of Nuclear Medicine and Allied Sciences (INMAS), Timarpur, Delhi, India
| | - Quincy A Hathaway
- Department of Cardiology, West Virginia University School of Medicine, Heart & Vascular Institute, Morgantown, WV, USA
| | - Amina Kunovac
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | | | - Vishnu Swarup
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Himanshu Narayan Singh
- Aix-Marseille University, INSERM, TAGC, UMR 1090, Marseille 13288, France.,MTA Infotech, Varanasi, India
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3
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Xu Q, Gu S, Liang J, Lin Z, Zheng S, Yan J. The Biological Function of Hepatitis B Virus X Protein in Hepatocellular Carcinoma. Oncol Res 2019; 27:509-514. [PMID: 29891022 PMCID: PMC7848407 DOI: 10.3727/096504018x15278771272963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the major malignant tumors that lead to death. Chronic hepatitis B virus infection is an important risk factor for HCC initiation. HBx protein, encoded by the HBV X gene, is a significant factor that promotes HBV-related HCC, although the exact molecular mechanism remains unclear. This article summarizes the pathological roles and related mechanisms of HBx in HCC. HBx plays a carcinogenic role by promoting cell proliferation, metastasis, and angiogenesis and inhibiting apoptosis in HCC. A detailed study of the biological functions of HBx will help to elucidate the mechanism of hepatocarcinogenesis and lead to the development of novel therapeutic targets for the treatment of HBV-related HCC.
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Affiliation(s)
- Qiaodong Xu
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
| | - Songgang Gu
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
| | - Jiahong Liang
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
| | - Zhihua Lin
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
| | - Shaodong Zheng
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
| | - Jiang Yan
- Department of Biliary-Pancreatic Minimally Invasive Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, P.R. China
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4
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Cho MY, Cheong JY, Lim W, Jo S, Lee Y, Wang HJ, Han KH, Cho H. Prognostic significance of catalase expression and its regulatory effects on hepatitis B virus X protein (HBx) in HBV-related advanced hepatocellular carcinomas. Oncotarget 2015; 5:12233-46. [PMID: 25361011 PMCID: PMC4322996 DOI: 10.18632/oncotarget.2625] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/23/2014] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus X protein (HBx) plays a role in liver cancer development. We previously showed that ROS increased HBx levels and here, we investigated the role of antioxidants in the regulation of HBx expression and their clinical relevance. We found that overexpression of catalase induced a significant loss in HBx levels. The cysteine null mutant of HBx (Cys-) showed a dramatic reduction in its protein stability. In clonogenic proliferation assays, Huh7-X cells produced a significant number of colonies whereas Huh7-Cys- cells failed to generate them. The Cys at position 69 of HBx was crucial to maintain its protein stability and transactivation function in response to ROS. Among 50 HBV-related hepatocellular carcinoma (HCC) specimens, 72% of HCCs showed lower catalase levels than those of surrounding non-tumor tissues. In advanced stage IV, catalase levels in non-tumor tissues were increased whereas those in tumors were further reduced. Accordingly, patients with a high T/N ratio for catalase showed significantly longer survival than those with a low T/N ratio. Together, catalase expression in HCC patients can be clinically useful for prediction of patient survival, and restoration of catalase expression in HCCs could be an important strategy for intervention in HBV-induced liver diseases.
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Affiliation(s)
- Mi-Young Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, Korea
| | - Jae Youn Cheong
- Department of Gastroenterology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea
| | - Wonchung Lim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Current address: Department of Sports Medicine, Cheongju University, Cheongju, Korea
| | - Sujin Jo
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Youngsoo Lee
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Hee-Jung Wang
- Department of Surgery, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea
| | - Kyou-Hoon Han
- Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Hyeseong Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, Korea. Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
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5
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Chen YF, Chong CL, Wu YC, Wang YL, Tsai KN, Kuo TM, Hong MH, Hu CP, Chen ML, Chou YC, Chang C. Doxorubicin Activates Hepatitis B Virus Replication by Elevation of p21 (Waf1/Cip1) and C/EBPα Expression. PLoS One 2015; 10:e0131743. [PMID: 26121644 PMCID: PMC4486450 DOI: 10.1371/journal.pone.0131743] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 06/05/2015] [Indexed: 01/10/2023] Open
Abstract
Hepatitis B virus reactivation is an important medical issue in cancer patients who undergo systemic chemotherapy. Up to half of CHB carriers receiving chemotherapy develop hepatitis and among these cases a notable proportion are associated with HBV reactivation. However, the molecular mechanism(s) through which various chemotherapeutic agents induce HBV reactivation is not yet fully understood. In this study, we investigated the role of the cell cycle regulator p21 (Waf1/Cip1) in the modulation of HBV replication when a common chemotherapeutic agent, doxorubicin, is present. We showed that p21 expression was increased by doxorubicin treatment. This elevation in p21 expression enhanced the expression of CCAAT/enhancer-binding protein α (C/EBPα); such an increase is likely to promote the binding of C/EBPα to the HBV promoter, which will contribute to the activation of HBV replication. Our current study thus reveals the mechanism underlying doxorubicin modulation of HBV replication and provides an increased understanding of HBV reactivation in CHB patients who are receiving systemic chemotherapy.
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Affiliation(s)
- Yu-Fang Chen
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Chin-Liew Chong
- Faculty of Traditional Chinese Medicine, Southern University College, Johor Bahru, Malaysia
| | - Yi-Chieh Wu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Yi-Ling Wang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Kuen-Nan Tsai
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan; Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Tzer-Min Kuo
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Ming-Hsiang Hong
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Cheng-Po Hu
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Mong-Liang Chen
- Center for Molecular Medicine, China Medical University and Hospital, Taichung, Taiwan
| | - Yu-Chi Chou
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chungming Chang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
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6
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Kim S, Lee HS, Ji JH, Cho MY, Yoo YS, Park YY, Cha HJ, Lee Y, Kim Y, Cho H. Hepatitis B virus X protein activates the ATM-Chk2 pathway and delays cell cycle progression. J Gen Virol 2015; 96:2242-2251. [PMID: 25872745 DOI: 10.1099/vir.0.000150] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genetic instability is intimately associated with tumour development. In particular, liver cancers associated with hepatitis B virus (HBV) exhibit high genetic instability; however, our understanding of the underlying molecular mechanisms remains limited. In this study, we found that γ-H2AX, a marker of DNA double-strand breaks (DSBs), and the levels of phospho-Chk2 (p-Chk2, the activated form) were significantly elevated in HBV-associated hepatocellular carcinomas and neighbouring regenerating nodules. Likewise, introduction of the pHBV or pMyc-HBx plasmids into cells induced accumulation of γ-H2AX foci and increased the p-Chk2 level. In these cells, inhibitory phosphorylation of Cdc25C phosphatase (Ser(216)) and CDK1 (Tyr(15)) was elevated; consequently, cell-cycle progression was delayed at G2/M phase, suggesting that activation of the ATM-Chk2 pathway by the HBV X protein (HBx) induces cell-cycle delay. Accordingly, inhibition of ataxia telangiectasia mutated (ATM) by caffeine or siRNA abolished the increase in the p-Chk2 level and restored the delayed CDK1 kinase activity in ChangX cells. We also found that cytoplasmic HBx, but not nuclear HBx, induced reactive oxygen species (ROS) production and led to the accumulation of γ-H2AX foci and the increased p-Chk2 level. Together, these data indicate that HBx-induced ROS accumulation induces DNA damage that activates the ATM-Chk2 pathway. Our findings provide insight into the mechanisms of HBV pathogenesis.
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Affiliation(s)
- Sujeong Kim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Ho-Soo Lee
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, The Graduate School of Ajou University, Suwon, Republic of Korea
| | - Jae-Hoon Ji
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Mi-Young Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, The Graduate School of Ajou University, Suwon, Republic of Korea
| | - Young-Suk Yoo
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea.,Department of Biomedical Sciences, The Graduate School of Ajou University, Suwon, Republic of Korea
| | - Yong-Yea Park
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hyuk-Jin Cha
- Department of Life Sciences, Sogang University, Seoul, Republic of Korea
| | - Youngsoo Lee
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Youngbae Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hyeseong Cho
- Department of Biomedical Sciences, The Graduate School of Ajou University, Suwon, Republic of Korea.,Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea.,Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Republic of Korea
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7
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Califano R, Morgillo F, De Mello RA, Mountzios G. Role of mesenchymal-epithelial transition amplification in resistance to anti-epidermal growth factor receptor agents. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:81. [PMID: 25992380 PMCID: PMC4416951 DOI: 10.3978/j.issn.2305-5839.2015.03.44] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/06/2015] [Indexed: 11/14/2022]
Abstract
All patients with epidermal growth factor receptor (EGFR) mutant advanced non-small cell lung cancer (NSCLC) treated with an EGFR-tyrosine kinase inhibitor (EGFR-TKI) such as gefitinib, erlotinib or afatinib will progress after a median of 9-12 months. So far, development of a secondary T790M mutation represents the most common (approximately 60%) mechanism of resistance to these drugs. The relative rarity of mesenchymal-epithelial transition (MET) amplification in NSCLC suggests that this event plays a limited role in primary resistance to EGFR-TKI. In contrast, MET gene amplification has been detected as a secondary event representing one of the most relevant mechanisms involved in the acquired resistance to EGFR-TKIs both in preclinical and clinical studies. The aim of this review is to discuss the role of MET amplification as a mechanism of resistance to anti-EGFR therapies and to review strategies which aim at overcoming this mechanism of resistance, including studies assessing drug combinations targeting both EGFR and MET pathways.
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8
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Higgs MR, Chouteau P, Lerat H. 'Liver let die': oxidative DNA damage and hepatotropic viruses. J Gen Virol 2014; 95:991-1004. [PMID: 24496828 DOI: 10.1099/vir.0.059485-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic infections by the hepatotropic viruses hepatitis B virus (HBV) and hepatitis C virus (HCV) are major risk factors for the development of hepatocellular carcinoma (HCC). It is estimated that more than 700,000 individuals per year die from HCC, and around 80 % of HCC is attributable to HBV or HCV infection. Despite the clear clinical importance of virus-associated HCC, the underlying molecular mechanisms remain largely elusive. Oxidative stress, in particular DNA lesions associated with oxidative damage, play a major contributory role in carcinogenesis, and are strongly linked to the development of many cancers, including HCC. A large body of evidence demonstrates that both HBV and HCV induce hepatic oxidative stress, with increased oxidative DNA damage being observed both in infected individuals and in murine models of infection. Here, we review the impact of HBV and HCV on the incidence and repair of oxidative DNA damage. We begin by giving a brief overview of oxidative stress and the repair of DNA lesions induced by oxidative stress. We then review in detail the evidence surrounding the mechanisms by which both viruses stimulate oxidative stress, before focusing on how the viral proteins themselves may perturb the cellular response to oxidative DNA damage, impacting upon genome stability and thus hepatocarcinogenesis.
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Affiliation(s)
- Martin R Higgs
- School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | | | - Hervé Lerat
- INSERM U955, Université Paris-Est, Créteil, France
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9
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Gelsomino F, Facchinetti F, Haspinger E, Garassino M, Trusolino L, De Braud F, Tiseo M. Targeting the MET gene for the treatment of non-small-cell lung cancer. Crit Rev Oncol Hematol 2014; 89:284-99. [DOI: 10.1016/j.critrevonc.2013.11.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/06/2013] [Accepted: 11/21/2013] [Indexed: 12/27/2022] Open
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10
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Chae S, Ji JH, Kwon SH, Lee HS, Lim JM, Kang D, Lee CW, Cho H. HBxAPα/Rsf-1-mediated HBx-hBubR1 interactions regulate the mitotic spindle checkpoint and chromosome instability. Carcinogenesis 2013; 34:1680-8. [PMID: 23536579 DOI: 10.1093/carcin/bgt105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hepatitis B virus (HBV) X protein (HBx), encoded by the HBV genome, is involved in the development of HBV-mediated liver cancer, whose frequency is highly correlated with chromosomal instability (CIN). We reported previously that HBx induces mitotic checkpoint dysfunction by targeting the human serine/threonine kinase BubR1 (hBubR1). However, the underlying mechanism remained unresolved. Here, we show that HBx protein-associated protein α (HBxAPα)/Rsf-1 associates with hBubR1 and HBx in the chromatin fraction during mitosis. Depletion of HBxAPα/Rsf-1 abolished the interaction between HBx and hBubR1, indicating that HBxAPα/Rsf-1 mediates these interactions. Knockdown of HBxAPα/Rsf-1 with small interfering RNA did not affect the recruitment of hBubR1 to kinetochores; however, it did significantly impair HBx targeting to kinetochores. A deletion mutant analysis revealed that two Kunitz domains of HBx, the Cdc20-binding domain of hBubR1 and full-length of HBxAPα/Rsf-1 were essential for these interactions. Thus, binding of HBx to hBubR1, stabilized by HBxAPα/Rsf-1, significantly attenuated hBubR1 binding to Cdc20 and consequently increased the rate of mitotic aberrations. Collectively, our data show that the HBx impairs hBubR1 function and induces CIN through HBxAPα/Rsf-1, providing a novel mechanism for induction of genomic instability by a viral pathogen in hepatocarcinogenesis.
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Affiliation(s)
- Sunyoung Chae
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine and the Graduate School of Molecular Science and Technology, Ajou University, Suwon, South Korea
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11
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Pritchard JE, Dillon PM, Conaway MR, Silva CM, Parsons SJ. A mechanistic study of the effect of doxorubicin/adriamycin on the estrogen response in a breast cancer model. Oncology 2012; 83:305-20. [PMID: 22964943 DOI: 10.1159/000341394] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 06/19/2012] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Estrogen treatment limits the cytotoxic effects of chemotherapy in estrogen receptor-positive (ER+) breast cancer cell lines, suggesting that estrogen pathway signaling may confer chemotherapeutic resistance. This study investigates the molecular responses of ER+ breast cancer cell lines to the chemotherapeutic agent, doxorubicin, in the presence or absence of estrogen. METHODS ER+ MCF-7 and T47-D cells were cultured in hormone-starved or estrogen-containing media with or without doxorubicin at concentrations mimicking the low concentrations seen in plasma and tumor microenvironments in humans following typical bolus administration. Protein levels, phosphorylations, and interactions of estrogen-signaling molecules were assessed following these treatments, as well the effects of ER signaling inhibitors on cell proliferation. RESULTS Surprisingly, estrogen and doxorubicin co-treatment markedly induced pro-growth alterations compared to doxorubicin alone and modestly enhanced estrogen alone-induced changes. Several inhibitors suppressed cell proliferation in the presence of doxorubicin and estrogen. CONCLUSIONS These findings demonstrate that molecular changes caused by doxorubicin in ER+ breast cancer cells can be reversed by estrogen, providing molecular evidence for the poorer responses of ER+ tumors to doxorubicin in the presence of physiologic estrogen levels. Our results also suggest that the addition of drugs targeting the ER, EGFR, the SFKs, MEK, PI3K, and/or the MMP proteins to a conventional chemotherapy regimen may improve chemosensitivity.
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Affiliation(s)
- Jessica E Pritchard
- Department of Microbiology and Cancer Center, University of Virginia, Charlottesville, VA 22908, USA
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12
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Wang W, Zhou D, Wei J, Wu Z, Cheng X, Sun Q, Xie H, Zhou L, Zheng S. Hepatitis B virus X protein inhibits p53-mediated upregulation of mitofusin-2 in hepatocellular carcinoma cells. Biochem Biophys Res Commun 2012; 421:355-60. [DOI: 10.1016/j.bbrc.2012.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 04/03/2012] [Indexed: 02/07/2023]
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13
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Chen S, Evans HG, Evans DR. FLASH knockdown sensitizes cells to Fas-mediated apoptosis via down-regulation of the anti-apoptotic proteins, MCL-1 and Cflip short. PLoS One 2012; 7:e32971. [PMID: 22427918 PMCID: PMC3302898 DOI: 10.1371/journal.pone.0032971] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/06/2012] [Indexed: 12/24/2022] Open
Abstract
FLASH (FLICE-associated huge protein or CASP8AP2) is a large multifunctional protein that is involved in many cellular processes associated with cell death and survival. It has been reported to promote apoptosis, but we show here that depletion of FLASH in HT1080 cells by siRNA interference can also accelerate the process. As shown previously, depletion of FLASH halts growth by down-regulating histone biosynthesis and arrests the cell cycle in S-phase. FLASH knockdown followed by stimulating the cells with Fas ligand or anti-Fas antibodies was found to be associated with a more rapid cleavage of PARP, accelerated activation of caspase-8 and the executioner caspase-3 and rapid progression to cellular disintegration. As is the case for most anti-apoptotic proteins, FLASH was degraded soon after the onset of apoptosis. Depletion of FLASH also resulted in the reduced intracellular levels of the anti-apoptotic proteins, MCL-1 and the short isoform of cFLIP. FLASH knockdown in HT1080 mutant cells defective in p53 did not significantly accelerate Fas mediated apoptosis indicating that the effect was dependent on functional p53. Collectively, these results suggest that under some circumstances, FLASH suppresses apoptosis.
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Affiliation(s)
- Song Chen
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Hedeel Guy Evans
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan, United States of America
| | - David R. Evans
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
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14
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Molina-Jiménez F, Benedicto I, Murata M, Martín-Vílchez S, Seki T, Antonio Pintor-Toro J, Tortolero M, Moreno-Otero R, Okazaki K, Koike K, Barbero JL, Matsuzaki K, Majano PL, López-Cabrera M. Expression of pituitary tumor-transforming gene 1 (PTTG1)/securin in hepatitis B virus (HBV)-associated liver diseases: evidence for an HBV X protein-mediated inhibition of PTTG1 ubiquitination and degradation. Hepatology 2010; 51:777-87. [PMID: 20198633 DOI: 10.1002/hep.23468] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Chronic infection with hepatitis B virus (HBV) is strongly associated with hepatocellular carcinoma (HCC), and the viral HBx protein plays a crucial role in the pathogenesis of liver tumors. Because the protooncogene pituitary tumor-transforming gene 1 (PTTG1) is overexpressed in HCC, we investigated the regulation of this protein by HBx. We analyzed PTTG1 expression levels in liver biopsies from patients chronically infected with HBV, presenting different disease stages, and from HBx transgenic mice. PTTG1 was undetectable in biopsies from chronic hepatitis B patients or from normal mouse livers. In contrast, hyperplastic livers from transgenic mice and biopsies from patients with cirrhosis, presented PTTG1 expression which was found mainly in HBx-expressing hepatocytes. PTTG1 staining was further increased in HCC specimens. Experiments in vitro revealed that HBx induced a marked accumulation of PTTG1 protein without affecting its messenger RNA levels. HBx expression promoted the inhibition of PTTG1 ubiquitination, which in turn impaired its degradation by the proteasome. Glutathione S-transferase pull-down and co-immunoprecipitation experiments demonstrated that the interaction between PTTG1 and the Skp1-Cul1-F-box ubiquitin ligase complex (SCF) was partially disrupted, possibly through a mechanism involving protein-protein interactions of HBx with PTTG1 and/or SCF. Furthermore, confocal analysis revealed that HBx colocalized with PTTG1 and Cul1. We propose that HBx promotes an abnormal accumulation of PTTG1, which may provide new insights into the molecular mechanisms of HBV-related pathogenesis of progressive liver disease leading to HCC development.
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15
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Lee YM, Kang M, Hwang JM, Lee S, Cho H, Kim YS. Sulfasalazine induces apoptosis of HBx-expressing cells in an NF-kappaB-independent manner. Virus Genes 2009; 40:37-43. [PMID: 19859796 DOI: 10.1007/s11262-009-0416-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 10/15/2009] [Indexed: 01/17/2023]
Abstract
The Hepatitis B virus (HBV) is a causative agent of acute chronic hepatitis, cirrhosis, and hepatocarcinoma. The Hepatitis B virus X protein (HBx) has pleiotypic functions in the regulation of proliferation and apoptosis. It has been suggested that the anti-inflammatory drug sulfasalazine, which is commonly used to treat rheumatoid arthritis and inflammatory bowel disease, inhibits nuclear factor NF-kappaB and induces cell death in HBx-expressing liver cells. In this study, we demonstrate that sulfasalazine induces cell death via apoptosis in HBx-expressing liver cells, as evidenced by characteristic changes in nuclear morphology, cleavage of poly (ADP-ribose) polymerase (PARP), caspase-3 and caspase-9, and activation of caspase-3. We also demonstrate that inhibition of NF-kappaB by siRNA fails to induce apoptosis of HBx-expressing liver cells, indicating that sulfasalazine modulates apoptosis of HBx-expressing cells in an NF-kappaB-independent manner.
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Affiliation(s)
- Young-Man Lee
- Indang Institute of Molecular Biology, Inje University, Jeodong 2-Ga 64, Chung-Ku, Seoul, 100-032, Republic of Korea
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16
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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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17
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Lee BS, Park M, Cha HY, Lee JH. Hepatocyte growth factor induces delayed STAT3 phosphorylation through interleukin-6 expression. Cell Signal 2008; 21:419-27. [PMID: 19071214 DOI: 10.1016/j.cellsig.2008.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Revised: 11/13/2008] [Accepted: 11/15/2008] [Indexed: 11/30/2022]
Abstract
Met receptor tyrosine kinase mediates pleiotropic cellular responses following its activation by hepatocyte growth factor or scatter factor (HGF/SF). STAT3 was reported to be one of direct downstream molecules in HGF/SF-Met signaling. In the present study, however, we observed that Tyr705 of STAT3 was phosphorylated from 2 h or 6 h in NIH3T3 and Chang liver cells, respectively, after HGF/SF treatment. Blocking of the phosphorylation by cycloheximide or actinomycin D and the rapid STAT3 phosphorylation with the conditioned medium from HGF/SF-treated NIH3T3 cells suggested that a newly synthesized secretory protein was responsible for the delayed STAT3 phosphorylation. Among the known mediators to induce STAT3 phosphorylation, interleukin-6 (IL-6) mRNA and protein were induced by HGF/SF, and the released IL-6 was accumulated in the conditioned medium after HGF/SF treatment. Furthermore, the neutralizing IL-6 antibody abolished the STAT3 phosphorylation. Treatment with LY294002, a PI3 kinase inhibitor, but not with other signal inhibitors, resulted in the loss of delayed STAT3 phosphorylation by HGF/SF, showing the involvement of PI3 kinase pathway. Collectively, these results demonstrate that HGF/SF-Met signal cascade stimulates IL-6 production via PI3 kinase pathway, leading to STAT3 phosphorylation as a secondary effect.
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Affiliation(s)
- Bok-Soon Lee
- Department of Biochemistry and Molecular Biology, Ajou University Medical School, 5 Wonchon-Dong, Yeongtong-Gu, Suwon 443-721, South Korea
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18
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Wang JH, Yun C, Kim S, Chae S, Lee YI, Kim WH, Lee JH, Kim W, Cho H. Reactivation of p53 in cells expressing hepatitis B virus X-protein involves p53 phosphorylation and a reduction of Hdm2. Cancer Sci 2008; 99:888-93. [PMID: 18294283 PMCID: PMC11159080 DOI: 10.1111/j.1349-7006.2008.00754.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 01/05/2008] [Accepted: 01/07/2008] [Indexed: 12/20/2022] Open
Abstract
Multifunctional activities of the hepatitis B virus X-protein (HBx) in cells have been largely implicated in the development of liver cancer; one of these activities is the loss of p53 function by sequestering p53 in the cytoplasm. We have previously found that doxorubicin increased the p53 levels in cells containing p53-binding HBx protein and restored the p53-mediated transcriptional activity that was suppressed by HBx. Here, we investigated the mechanism underlying p53 reactivation. We found that six phosphorylation sites of the Serine residues of p53 were efficiently phosphorylated in HBx-expressing ChangX-34 cells, suggesting that the binding of HBx to the p53 protein does not interfere with the phosphorylation of p53 by signaling kinases. In addition, doxorubicin caused a dramatic reduction of Hdm2 mRNA and protein levels in cells expressing HBx. Intriguingly, reactivation of p53 was accompanied with a nuclear accumulation of p53 and the phosphorylated p53 at Serine15 was only detected in nuclear fraction, but not in cytosolic fraction of doxorubicin-treated ChangX-34 cells. Functional restoration of the p53 protein in HBx-expressing cells occurs according to the dual effects of doxorubicin: a significant reduction of Hdm2 expression and a nuclear accumulation of the phosphorylated p53 protein. Thus, proper usage of doxorubicin as an effective antitumor agent may be reevaluated and can be extended to tumors primarily caused by infection of DNA tumor viruses.
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Affiliation(s)
- Jin-Hee Wang
- Department of Biochemistry, Ajou University School of Medicine, San 5 Wonchun-dong, Yeongtang-gu, Suwon 443-721, Korea
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19
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Kim S, Kim HY, Lee S, Kim SW, Sohn S, Kim K, Cho H. Hepatitis B virus x protein induces perinuclear mitochondrial clustering in microtubule- and Dynein-dependent manners. J Virol 2007; 81:1714-26. [PMID: 17151129 PMCID: PMC1797565 DOI: 10.1128/jvi.01863-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hepatitis B virus (HBV) X protein (HBx) is thought to play a key role in HBV replication and the development of liver cancer. It became apparent that HBx induces mitochondrial clustering at the nuclear periphery, but the molecular basis for mitochondrial clustering is not understood. Since mitochondria move along the cytoskeleton as a cargo of motor proteins, we hypothesized that mitochondrial clustering induced by HBx occurs by an altered intracellular motility. Here, we demonstrated that the treatment of HBx-expressing cells with a microtubule-disrupting drug (nocodazole) abrogated mitochondrial clustering, while the removal of nocodazole restored clustering within 30 to 60 min, indicating that mitochondrial transport is occurring in a microtubule-dependent manner. The addition of a cytochalasin D-disrupting actin filament, however, did not measurably affect mitochondrial clustering. Mitochondrial clustering was further studied by observations of HBV-related hepatoma cells and HBV-replicating cells. Importantly, the abrogation of the dynein activity in HBx-expressing cells by microinjection of a neutralizing anti-dynein intermediate-chain antibody, dynamitin overexpression, or the addition of a dynein ATPase inhibitor significantly suppressed the mitochondrial clustering. In addition, HBx induced the activation of the p38 mitogen-activated protein kinase (MAPK) and inhibition of the p38 kinase activity by SB203580-attenuated HBx-induced mitochondrial clustering. Taken together, HBx activation of the p38 MAPK contributed to the increase in the microtubule-dependent dynein activity. The data suggest that HBx plays a novel regulatory role in subcellular transport systems, perhaps facilitating the process of maturation and/or assembly of progeny particles during HBV replication. Furthermore, mitochondrion aggregation induced by HBx may represent a cellular process that underlies disease progression during chronic viral infection.
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Affiliation(s)
- Sujeong Kim
- Department of Biochemistry, Ajou University School of Medicine, 5 Wonchon-dong, Yeongtong-gu, Suwon 443-721, Korea
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20
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Um HR, Lim WC, Chae SY, Park S, Park JH, Cho H. Raf-1 and protein kinase B regulate cell survival through the activation of NF-kappaB in hepatitis B virus X-expressing cells. Virus Res 2006; 125:1-8. [PMID: 17188775 DOI: 10.1016/j.virusres.2006.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 11/10/2006] [Accepted: 11/10/2006] [Indexed: 12/17/2022]
Abstract
We previously demonstrated that activation of NF-kappaB by the hepatitis B virus X (HBx) gene plays an important role in cell survival. In the present study, we explored the upstream mediators of NF-kappaB activation and their correlations with cell survival. XTT assays and colony generation assays revealed that inhibition of NF-kappaB activation indeed increased cell death in HBx-expressing cells. Utilizing inactivating mutants of signal transducers, we showed that dominant negative mutants of stress-activated protein kinase/extracellular signal-regulated kinase (SEK1) or PKCalpha significantly diminished the HBx-mediated NF-kappaB activation. However, neither of these mutants significantly affected the cell survival in colony generation assays. In contrast, inactivating mutants of Raf-1 or PKB (protein kinase B)/Akt abrogated the HBx-mediated NF-kappaB activation and also suppressed the cell survival. Our results suggest that the Raf-1 or PKB-mediated NF-kappaB activation promotes cell survival in HBx-expressing cells.
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Affiliation(s)
- Hae-Ryun Um
- Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, Republic of Korea
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21
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Kim JS, Rho BY, Lee TH, Lee JM, Kim SJ, Park JH. The interaction of hepatitis B virus X protein and protein phosphatase type 2 Calpha and its effect on IL-6. Biochem Biophys Res Commun 2006; 351:253-8. [PMID: 17055456 DOI: 10.1016/j.bbrc.2006.10.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 10/08/2006] [Indexed: 11/16/2022]
Abstract
HBx has been suggested as an important determinant mediating the pathological effects of HBV via interacting with various cellular proteins. To identify new HBx-interacting proteins and elucidate a possible mechanism associated with HBx and HBx-interacting proteins in hepatocellular carcinoma, yeast two-hybrid screening was performed. We identified a novel HBx-interacting protein, serine/threonine protein phosphatase PP2Calpha, and investigated the effects of PP2Calpha on HBx-mediated IL-6 regulation. The interaction between endogenous PP2Calpha, and HBx was confirmed by co-immunoprecipitation. Recombinant HBx dose-dependently reduced enzyme activity of recombinant PP2Calphain vitro. While ectopically expressed PP2Calpha in Cos-7 and Huh-7 cells reduced the expression of IL-6, overexpressed HBx with recombinant HBx-expressing adenovirus overcame PP2Calpha-mediated IL-6 downregulation. In the response of IL-6, HBx phosphorylated STAT3 and recovered PP2Calpha-mediated dephosphorylation of STAT3. These results supported that HBx might play a crucial role in HBV-associated hepatocarcinogenesis even in cases where cells express a negative regulator, PP2Calpha.
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Affiliation(s)
- Ji Su Kim
- Department of Microbiology and Brain Korea 21 Project for Medical Sciences, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
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22
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Jin YH, Kwon MH, Kim K, Shin HJ, Shin JS, Cho H, Park S. An intracellular antibody can suppress tumorigenicity in hepatitis B virus X-expressing cells. Cancer Immunol Immunother 2006; 55:569-78. [PMID: 16273352 PMCID: PMC11030035 DOI: 10.1007/s00262-005-0037-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Accepted: 12/30/2004] [Indexed: 10/25/2022]
Abstract
Although the hepatitis B virus X protein (HBx) is thought to play a causative role in the development of hepatocellular carcinoma, it is not yet known whether interfering with HBx function may affect the cellular transformation of HBx-expressing tumor cells. To address this question, we adopted an intracellular antibody fragment expression approach to block the function of HBx. Expression of a single-chain variable fragment (scFv) specific to HBx (designated as H7scFv) inhibited HBx-dependent cellular transactivation. Furthermore, H7scFv suppressed the growth of HBx-expressing tumor cells in both soft agar and nude mice. The suppressive effect of H7scFv on tumorigenicity appeared not to be mediated by inhibition of HBx-induced growth stimulation since the growth rate of these cells was not affected significantly by H7scFv expression. In conclusion, these data suggest that the HBx-dependent transformed phenotype is reversible and that HBx may be a good molecular target for the treatment of HBV-related tumors.
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Affiliation(s)
- Young-Hee Jin
- Department of Microbiology, Ajou University School of Medicine, San 5 wonchun-dong yeongtong-gu, Suwon, 442-749 Republic of Korea
| | - Myung-Hee Kwon
- Department of Microbiology, Ajou University School of Medicine, San 5 wonchun-dong yeongtong-gu, Suwon, 442-749 Republic of Korea
| | - Kyongmin Kim
- Department of Microbiology, Ajou University School of Medicine, San 5 wonchun-dong yeongtong-gu, Suwon, 442-749 Republic of Korea
| | - Ho Joon Shin
- Department of Microbiology, Ajou University School of Medicine, San 5 wonchun-dong yeongtong-gu, Suwon, 442-749 Republic of Korea
| | - Jeon-Soo Shin
- Department of Microbiology, Yonsei University College of Medicine, 134 sinchon-dong, seodaemun-gu, Seoul, 120-749 Republic of Korea
| | - Hyeseong Cho
- Department of Biochemistry, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Sun Park
- Department of Microbiology, Ajou University School of Medicine, San 5 wonchun-dong yeongtong-gu, Suwon, 442-749 Republic of Korea
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23
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Lee ATC, Ren J, Wong ET, Ban KHK, Lee LA, Lee CGL. The hepatitis B virus X protein sensitizes HepG2 cells to UV light-induced DNA damage. J Biol Chem 2005; 280:33525-35. [PMID: 16055925 DOI: 10.1074/jbc.m506628200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Various reports have implicated the virally encoded HBx protein as a cofactor in hepatocarcinogenesis. However, direct evidence of the role of HBx as a promoter of oncogenesis in response to an initiating factor such as DNA damage remains inadequate. Here, we report the effects of HBx in HepG2 cells exposed to UV light-induced DNA damage. HBx expression was found not to affect the morphology, viability, and cell cycle/apoptotic profiles or DNA repair machinery of untreated cells. Nonetheless, upon UV treatment, HBx protein levels increased concomitantly with p53 levels. Both HBx and p53 proteins were found to interact and colocalize primarily in the nucleus. The binding of HBx to p53 modulated (but did not inhibit) the transcriptional activation function of p53. Notably, HBx-expressing cells exhibited increased sensitivity to UV damage, resulting in greater G2/M arrest and apoptosis of these cells. Additionally, these cells displayed a reduced DNA repair capacity in response to UV damage. In conclusion, this work suggests that DNA damage may be an initiating factor in hepatocarcinogenesis and that HBx may act as the promoting factor by inhibiting DNA repair. In hepatitis B virus-infected hepatocytes, a chronic infection may present the opportunity for such a DNA-damaging event to occur, and accumulated errors caused by the inhibition of DNA repair by HBx may result in oncogenesis.
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Affiliation(s)
- Alvin T C Lee
- Division of Medical Sciences, National Cancer Centre, Singapore 169610, Singapore
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24
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Yoo YG, Lee MO. Hepatitis B virus X protein induces expression of Fas ligand gene through enhancing transcriptional activity of early growth response factor. J Biol Chem 2004; 279:36242-9. [PMID: 15173177 DOI: 10.1074/jbc.m401290200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
FasL expressed in tumor cells plays an important role in the escape from immune surveillance by inducing apoptosis in T-cells bearing Fas. Since the Fas/FasL signaling pathway requires transcriptional induction of the FasL gene, elucidation of the precise mechanisms underlying regulation of FasL gene expression may provide useful molecular insights on tumor progression. We and others (Shin, E. C., Shin, J. S., Park, J. H., Kim, H., and Kim, S. J. (1999) Int. J. Cancer 82, 587-591; Lee, M. O., Kang, H. J., Cho, H., Shin, E. C., Park, J. H., and Kim, S. J. (2001) Biochem. Biophys. Res. Commun. 288, 1162-1168) have previously reported that hepatitis B virus X protein (HBx) plays a role in the induction of FasL expression in hepatitis B virus-associated hepatoma. In the present study, we analyzed the potential cis- and trans-acting factors that regulate FasL promoter. We found that HBx induced activity of the reporter containing FasL promoter through binding site for Egr but not through NFAT or SP-1, which are known as strong activators of the FasL promoter in T-cells. Transient expression of antisense Egr-2 and antisense Egr-3 abolished expression of FasL, which further confirmed the role of Egr in the HBx-mediated FasL expression. Also we observed that HBx increased the transcriptional activity of Egr-2 and Egr-3 by enhancing expression as well as the transactivation function of these proteins. HBx interacted with Egr-2 and Egr-3 in vivo and enhanced binding of Egr to the co-activator, cAMP-response element-binding protein-binding protein, which may explain the molecular mechanism by which HBx induced the transactivation function of Egr. Finally, we found that the carboxyl terminus of HBx was necessary and sufficient for FasL induction as well as activation of Egr. Taken together, our results show a novel mechanism by which HBx induces FasL gene expression that is mediated by enhancing transcriptional activity of Egr-2 and Egr-3.
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Affiliation(s)
- Young-Gun Yoo
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Korea
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25
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Chi TY, Chen GG, Lai PBS. Eicosapentaenoic Acid Induces Fas-Mediated Apoptosis Through a p53-Dependent Pathway in Hepatoma Cells. Cancer J 2004; 10:190-200. [PMID: 15285929 DOI: 10.1097/00130404-200405000-00009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Eicosapentaenoic acid (EPA) has been demonstrated to induce apoptosis and cell cycle arrest in various cancer cell lines in vitro. In this study, we investigated the anti-tumor effects of EPA on hepatoma cell lines and the mechanisms responsible for induced cell death. Three hepatoma cell lines tested had different p53 status: HepG2 with a wild-type p53; Hep3B, of which the endogenous p53 was deleted; and Huh7 with its p53 mutated. MTT assay showed reduced viability of HepG2 cells after exposure to EPA, and the cytotoxicity of EPA was time and dose dependent. However, EPA had no effect on the viability and cell death in the two other hepatoma cell lines containing dysfunctional p53. DNA fragmentation analysis and TUNEL (terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridine diphosphate [dUTP] nick end labeling) staining showed a typical pattern of DNA laddering and DNA breaks staining, respectively, in wild-type p53-containing HepG2 cells after EPA treatment. We also observed that EPA induced transient nuclear accumulation of P53 protein that subsequently up-regulated the expression of Fas messenger RNA and protein in HepG2 cells. In contrast, these findings were not observed in Hep3B and Huh7 cells exposed to EPA. Most notably, EPA-induced apoptosis in HepG2 cells could be reduced almost completely by treatment with FasL antisense oligonucleotides. We conclude that EPA inhibits the growth of HepG2 cells and mediates its effect, at least in part, via the Fas-mediated apoptosis. It appears that the effects of EPA on hepatoma cells are determined by the status of p53 and that wild-type p53 is a prerequisite for the anticancer effect of EPA.
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Affiliation(s)
- Tian-Yi Chi
- Department of Surgery, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
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26
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Choi YH, Kim HI, Seong JK, Yu DY, Cho H, Lee MO, Lee JM, Ahn YH, Kim SJ, Park JH. Hepatitis B virus X protein modulates peroxisome proliferator-activated receptor gamma through protein-protein interaction. FEBS Lett 2004; 557:73-80. [PMID: 14741344 DOI: 10.1016/s0014-5793(03)01449-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ligand activation of peroxisome proliferator-activated receptor gamma (PPARgamma) has been reported to induce growth inhibition and apoptosis in various cancers including hepatocellular carcinoma (HCC). However, the effect of hepatitis B virus X protein (HBx) on PPARgamma activation has not been characterized in hepatitis B virus (HBV)-associated HCC. Herein, we demonstrated that HBx counteracted growth inhibition caused by PPARgamma ligand in HBx-associated HCC cells. We found that HBx bound to DNA binding domain of PPARgamma and HBx/PPARgamma interaction blocked nuclear localization and binding to recognition site of PPARgamma. HBx significantly suppressed a PPARgamma-mediated transactivation. These results suggest that HBx modulates PPARgamma function through protein-protein interaction.
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Affiliation(s)
- Youn-Hee Choi
- Department of Microbiology and Brain Korea 21 Project of Medical Sciences, Institute for Immunology and Immunological Diseases, Seoul, South Korea
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27
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Yun C, Cho H, Kim SJ, Lee JH, Park SY, Chan GK, Cho H. Mitotic Aberration Coupled With Centrosome Amplification Is Induced by Hepatitis B Virus X Oncoprotein via the Ras-Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase-Mitogen-Activated Protein Pathway. Mol Cancer Res 2004. [DOI: 10.1158/1541-7786.159.2.3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Multinucleated cells have been noted in pathophysiological states of the liver including infection with hepatitis B virus (HBV), the status of which is also closely associated with genomic instability in liver cancer. Here, we showed that hepatitis B virus X oncoprotein (HBx) expression in Chang cells results in a multinuclear phenotype and an abnormal number of centrosomes (n ≥ 3). Regulation of centrosome duplication in HBx-expressing ChangX-34 cells was defective and uncoupled from the cell cycle. HBx induced amplification of centrosomes, multipolar spindle formation, and chromosomal missegregation during mitosis and subsequently increased the generation of multinucleated cells and micronuclei formation. Treatment with PD98059, a mitogen-activated protein/extracellular signal-regulated kinase (MEK) 1/2 inhibitor, significantly reduced the number of cells with hyperamplified centrosomes and decreased the multinucleated cells and micronuclei formation. Consistently, the phospho-ERK level during cell progression was substantially higher in ChangX-34 cells than that of Chang cells. In contrast, neither wortmannin, an inhibitor of phosphoinositide-3 kinase, nor SB203589, an inhibitor of p38 mitogen-activated protein kinase (MAPK), showed any effects. Introduction of Ras dominant-negative (D/N) and MEK2 D/N genes into ChangX-34 cells significantly alleviated centrosome amplification, whereas introduction of the PKC D/N and PKB D/N genes did not. Thus, our results demonstrate that the HBx induced centrosome hyperamplification and mitotic aberration by activation of the Ras-MEK-MAPK. Intervention of this signaling pathway could suppress the centrosome amplification as well as mitotic aberration. These findings may provide a possible mechanism by which HBx promotes phenotypic progression by predisposing chromosomal alteration in HBV-infected liver.
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Affiliation(s)
- Chawon Yun
- 1Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, South Korea
| | - Hyeseon Cho
- 2Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD; and
| | - Su-Jeong Kim
- 1Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, South Korea
| | - Jae-Ho Lee
- 1Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, South Korea
| | - Sun Yi Park
- 1Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, South Korea
| | - Gordon K. Chan
- 3Department of Experimental Oncology, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Hyeseong Cho
- 1Department of Biochemistry and Molecular Biology, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, South Korea
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Wang JH, Yun C, Kim S, Lee JH, Yoon G, Lee MO, Cho H. Reactive oxygen species modulates the intracellular level of HBx viral oncoprotein. Biochem Biophys Res Commun 2003; 310:32-9. [PMID: 14511644 DOI: 10.1016/j.bbrc.2003.08.113] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HBx (hepatitis B virus X) viral oncoprotein is a multifunctional protein of which the cellular level may be one of the important factors in determining HBV-mediated pathological progression of liver diseases, chronic hepatitis, and hepatocellular carcinoma. Our previous work revealed that adriamycin, a chemotherapeutic agent, caused a marked increase in the intracellular level of HBx by retarding its rapid degradation. In the present study, modulation of HBx expression was found to be confined to adriamycin but not to other chemotherapeutic agents, cisplatin and 5-fluorouracil. Interestingly, adriamycin caused a rapid increase of reactive oxygen species (ROS) and its accumulation continued until 24h. In contrast, two other agents had little effect on ROS generation, suggesting the possible involvement of ROS in the HBx regulation. In fact, direct addition of H(2)O(2) to the cells significantly increased the level of HBx protein in HBx-expressing ChangX-34 cells as well as in hepatitis B virus-related hepatoma cells, PLC/PRF/5 and HepG2.2.15 cells. Furthermore, antioxidants, N-acetyl-cysteine and pyrrolidinedithiocarbamate (PDTC), completely abolished the increase of HBx protein induced by adriamycin, indicating that adriamycin modulates the intracellular HBx level via ROS generation. Together, these findings provide a novel aspect of HBx regulation by cellular ROS level. Therefore, intracellular microenvironments generating ROS such as severe inflammation may aggravate the pathogenesis of liver disease by accumulating the HBx level.
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Affiliation(s)
- Jin-Hee Wang
- Department of Biochemistry, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, 5 Wonchon-dong, Paldal-gu, Suwon 442-741, Republic of Korea
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29
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Yoo YG, Oh SH, Park ES, Cho H, Lee N, Park H, Kim DK, Yu DY, Seong JK, Lee MO. Hepatitis B virus X protein enhances transcriptional activity of hypoxia-inducible factor-1alpha through activation of mitogen-activated protein kinase pathway. J Biol Chem 2003; 278:39076-84. [PMID: 12855680 DOI: 10.1074/jbc.m305101200] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hepatitis B virus X protein (HBx) of the hepatitis B virus was strongly implicated in angiogenesis and metastasis during hepatocarcinogenesis. Here, we explored the possibility of cross-talk between HBx and hypoxia-inducible factor-1alpha (HIF-1alpha), a potent transcriptional inducer of angiogenic factors. First, we showed that stability of HIF-1alpha protein was increased by HBx in HBx-inducible Chang liver cells as well as in transient HBx expression system of non-hepatic cells. Immunofluorescence studies revealed that the HBx-induced HIF-1alpha was partially translocated into the nucleus in majority of cells while additional CoCl2-induced hypoxic condition caused complete nuclear translocation. Second, HBx induced both phosphorylation of HIF-1alpha and activation of p42/p44 mitogen-activated protein kinases (MAPKs), which were synergistically enhanced in the presence of CoCl2. Furthermore, HBx enhanced transcriptional activity of HIF-1alpha in the reporter genes encoding hypoxia response element or VEGF promoter. Either treatment of MEK inhibitor PD98059 or coexpression of dominant-negative MAPK mutants abolished the HBx-induced transcriptional activity and protein stability as well as nuclear translocation of HIF-1alpha, suggesting that HBx activates HIF-1alpha through MAPK pathway. Third, the association of HIF-1alpha with von Hippel-Lindau was decreased but the association with CREB-binding protein was enhanced in the presence of HBx, suggesting the molecular mechanism by which HBx enhances the protein stability and transactivation function of HIF-1alpha. Finally, we demonstrated that expression of HIF-1alpha and vascular endothelial growth factor was increased in the liver of HBx-transgenic mice, suggesting that the cross-talk between HIF-1alpha and HBx may lead to transcriptional activation of HIF-1alpha target genes, which play a critical role in hepatocarcinogenesis.
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Affiliation(s)
- Young-Gun Yoo
- Department of Bioscience and Biotechnology, Sejong University, Seoul 140-747, Korea
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30
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Lu YY, Chen TY, Cheng J, Liang YD, Wang L, Liu Y, Zhang J, Shao Q, Li K, Zhang LX. Cloning of a gene coding for novel mutant of asialoglycoprotein receptor 2 binding to hepatitis B virus X protein in hepatocytes. Shijie Huaren Xiaohua Zazhi 2003; 11:1126-1130. [DOI: 10.11569/wcjd.v11.i8.1126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM The pathogenesis of HBV-induced malignant transformation is incompletely understood. The X protein of hepatitis B virus (HBxAg) is a multifunctional protein that can influence a variety of signal transduction pathways within the cell and is essential for establishing natural viral infection, it also has been implicated in the development of liver cancer associated with chronic infection. Further understanding of the interaction between HBxAg and proteins in hepatocytes is of great significance for the prevention of the development of hepatocellular carcinoma (HCC).
METHODS HBxAg bait plasmid was constructed by ligating the HBxAg gene with a yeast expression vector pGBKT7, then transformed into yeast AH109 (a type). The transformed yeast cells were amplified and mated with yeast cells Y187(α type) containing liver cDNA library plasmid pCAT2 in 2×YPDA medium. Diploid yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-α-gal for selection twice. Plasmid of true positive blue colonies was extracted and analysed by DNA sequencing and blast in GenBank. After the complete sequence of the novel mutant of asialoglycoprotein receptor 2 (ASGPR2) was amplified from the mRNA of HepG2 cell by reverse transcription polymerase chain reaction (RT-PCR) and cloned into pGADT7 vector, the recombined plasmid was translated by using reticulocyte lysate and analysed by immunoprecipitation technique in vitro together with HBxAg.
RESULTS Eighteen genes in forty-one positive colonies were obtained, one of them is a novel mutant of ASGPR2, which is 80 % homologous to natural ASGPR2. The complete sequence of the mutant was amplified from the mRNA of HepG2 cell by RT-PCR successfully. The interaction between HBx and ASGPR2 mutant was further confirmed by immunoprecipitation technique.
CONCLUSION Interaction between HBx and ASGPR2 mutant can be observed in both yeast cell and in vitro.
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Affiliation(s)
- Yin-Ying Lu
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Tian-Yan Chen
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Jun Cheng
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Yao-Dong Liang
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Lin Wang
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Yan Liu
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Jian Zhang
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Qing Shao
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Ke Li
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
| | - Ling-Xia Zhang
- Gene Therapy Research Center, Institute of Infectious Diseases, The 302 Hospital of PLA, 100 Xisihuan Zhonglu, Beijing 100039, China
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31
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Yun C, Um HR, Jin YH, Wang JH, Lee MO, Park S, Lee JH, Cho H. NF-kappaB activation by hepatitis B virus X (HBx) protein shifts the cellular fate toward survival. Cancer Lett 2002; 184:97-104. [PMID: 12104053 DOI: 10.1016/s0304-3835(02)00187-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this paper, we examined the cellular effect of hepatitits B virus X (HBx) in ChangX-34 cells, inducible HBx-expressing cells. High expression of HBx protein in ChangX-34 cells resulted in approximately three-fold increase in DNA synthesis and did not show apoptotic changes. Expression of HBx in these cells was accompanied by the NF-kappaB-mediated transcription. Interestingly, inhibition of NF-kappaB activity either by treatment with sulfasalazine, a specific inhibitor of NF-kappaB, or by expressing IkappaBalpha super-repressor significantly increased cell death in ChangX-34 cells but had no influence on parental Chang cells. Thus, the activation of NF-kappaB in HBx-expressing cells may play a critical role in shifting the balance toward cell survival.
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Affiliation(s)
- Chawon Yun
- Department of Biochemistry, Ajou University School of Medicine, Suwon 442-749, South Korea
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32
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Yun C, Lee JH, Wang JH, Seong JK, Oh SH, Yu DY, Cho H. Expression of hepatitis B virus X (HBx) gene is up-regulated by adriamycin at the post-transcriptional level. Biochem Biophys Res Commun 2002; 296:1157-63. [PMID: 12207895 DOI: 10.1016/s0006-291x(02)02058-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hepatitis B virus (HBV) X protein (HBx) is thought to be involved in the development of liver cancer and alteration of cellular HBx level may influence the pathological progression of HBV-induced liver diseases. We found that the cellular levels of HBx mRNA transcript and protein in cells were greatly enhanced by adriamycin, a topoisomerase II inhibitor. Up-regulation of HBx mRNA by adriamycin was also observed in HBx transgenic mice, which was accompanied with a significant increase of VEGF mRNA, the downstream target of HBx. When we investigated the underlying mechanism, we found that half-life of HBx mRNA in HBx-expressing Chang cells was about 3h, but was prolonged to >6h in the presence of adriamycin. Moreover, half-life of rapidly degrading HBx protein was determined as about 15min however, it remained almost constant until 60min in the presence of adriamycin. These results provide the first evidence that the cellular level of HBx gene can be increased at the post-transcriptional level.
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Affiliation(s)
- Chawon Yun
- Department of Biochemistry, Ajou University School of Medicine, 5 Wonchon-dong, Paldal-ku, 442-749, Suwon, Republic of Korea
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33
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Lee MO, Choi YH, Shin EC, Kang HJ, Kim YM, Jeong SY, Seong JK, Yu DY, Cho H, Park JH, Kim SJ. Hepatitis B virus X protein induced expression of interleukin 18 (IL-18): a potential mechanism for liver injury caused by hepatitis B virus (HBV) infection. J Hepatol 2002; 37:380-6. [PMID: 12175634 DOI: 10.1016/s0168-8278(02)00181-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND/AIMS The hepatitis B virus X protein (HBx), a major viral transactivator, is implicated in hepatic inflammation, since it induces many pro-inflammatory cytokines at transcriptional level. The aim of this study was to investigate role of HBx in expression of interleukin 18 (IL-18), a newly identified cytokine that up-regulates Fas ligand (FasL) expression. METHODS Chang X-34 that expressing HBx under the control of a doxycycline-inducible promoter, and hepatitis B virus (HBV)-integrated hepatoma cell lines were examined for IL-18 expression by Northern and Western blotting analysis. To test the role of IL-18 produced by hepatoma cells, FasL expression was examined by flow cytometry after treatment with neutralizing anti-IL-18 antibodies. Further, IL-18 expression was examined in the liver tissues of HBx-transgenic mice. RESULTS Induction of IL-18 following HBx expression in Chang X-34 and the pattern of IL-18 expression in HBV-integrated cell lines, implicated that HBx transcriptionally induces IL-18 expression. Neutralizing anti-IL-18 antibodies blocked the expression of FasL, suggesting that IL-18 plays a critical role in FasL expression. Further, IL-18 expression in the HBx-transgenic liver, was correlated with the degree of hepatitis. CONCLUSIONS Our results demonstrated that HBx induces IL-18 expression in liver, which may be associated with hepatic injury by amplifying FasL expression during HBV infection.
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Affiliation(s)
- Mi-Ock Lee
- Department of Bioscience and Biotechnology, Sejong University, 98 Kunja-dong, Kwangjin-gu, Seoul 140-747, South Korea.
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34
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Lee MO, Kang HJ, Cho H, Shin EC, Park JH, Kim SJ. Hepatitis B virus X protein induced expression of the Nur77 gene. Biochem Biophys Res Commun 2001; 288:1162-8. [PMID: 11700033 DOI: 10.1006/bbrc.2001.5910] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Hepatitis B virus (HBV) X protein (HBx) plays an essential role in development of HBV-associated hepatocellular carcinoma (HCC). Recently, we reported that HBx induces Fas Ligand (FasL) expression, which may help HCC cells to evade host-immune surveillance. The aim of this study was to investigate the role of HBx in expression of Nur77, an orphan nuclear receptor implicated in the upregulation of FasL. When Chang X-34 expressing HBx under the control of a doxycycline-inducible promoter was examined, induction of Nur77 was observed following HBx expression. Blocking of Nur77 function by introduction of an antisense or a dominant negative mutant Nur77 significantly inhibited the induction of FasL, indicating that Nur77 plays critical roles in FasL expression. Further, a high-level expression of transcripts and DNA binding of Nur77 were observed in the HBV-integrated cell lines established from HCC patients that express HBx. These results suggested that Nur77 may contribute to leading the HBx-induced Fas/FasL signaling pathway which eliminates invading Fas-expressing lymphocytes.
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MESH Headings
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/virology
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Fas Ligand Protein
- Hepatitis B/genetics
- Hepatitis B/metabolism
- Hepatitis B/virology
- Hepatitis B virus/genetics
- Humans
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Liver Neoplasms/virology
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- Mutation
- Nuclear Receptor Subfamily 4, Group A, Member 1
- Oligonucleotides, Antisense/pharmacology
- Promoter Regions, Genetic
- RNA, Messenger/biosynthesis
- Receptors, Cytoplasmic and Nuclear
- Receptors, Steroid
- Trans-Activators/biosynthesis
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Trans-Activators/pharmacology
- Trans-Activators/physiology
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Transcription Factors/physiology
- Transcriptional Activation
- Transfection
- Tumor Cells, Cultured
- Viral Regulatory and Accessory Proteins
- Virus Integration
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Affiliation(s)
- M O Lee
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Korea.
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35
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Jin YM, Yun C, Park C, Wang HJ, Cho H. Expression of hepatitis B virus X protein is closely correlated with the high periportal inflammatory activity of liver diseases. J Viral Hepat 2001; 8:322-30. [PMID: 11555189 DOI: 10.1046/j.1365-2893.2001.00308.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hepatitis B virus X (HBx) protein is a multifunctional protein that exerts dual activity on cell proliferation and death. Although HBx is thought to be a major determinant that leads to hepatocellular carcinoma, its pathophysiological role in humans remains to be established. Attempts have been made to evaluate the role of HBx in liver specimens derived from patients with chronic B viral hepatitis and hepatocellular carcinoma. Among 25 paired liver specimens of hepatocellular carcinoma and corresponding nontumour liver tissues, HBx mRNA was hardly detected and was significantly lower than other HBV transcripts. An immunohistochemical study demonstrated that expression of HBx protein was also lower than other HBV gene products. Interestingly, however, expression of HBx protein changed with the progression of chronic hepatitis. HBx was expressed in 5.0% of patients with chronic hepatitis without cirrhosis but increased to 44.8% in chronic hepatitis with cirrhosis. In contrast, only one (3.7%) of 27 hepatocellular carcinomas showed HBx positivity whereas 29.6% of surrounding nontumour tissues was still HBx-positive. These results suggest that HBx may play a major role at the promotion stage of carcinogenesis. Noticeably, HBx-positive cells were preferentially localized in the periportal region of chronic hepatitis or periphery of cirrhotic nodules where high necroinflammatory activity was accompanied. We found a positive correlation between HBx expression and periportal inflammatory activity (P < 0.001). Thus, HBx may potentiate cell destruction and regeneration of liver that provide an opportunity for the accumulation of genetic mutations, which contribute to multistep hepatocarcinogenesis.
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MESH Headings
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Carcinoma, Hepatocellular/virology
- Gene Expression Regulation, Viral
- Hepatitis B virus/genetics
- Hepatitis B virus/metabolism
- Hepatitis B, Chronic/metabolism
- Hepatitis B, Chronic/pathology
- Hepatitis B, Chronic/virology
- Hepatocytes/metabolism
- Hepatocytes/pathology
- Hepatocytes/virology
- Humans
- Immunohistochemistry
- Inflammation/metabolism
- Inflammation/pathology
- Inflammation/virology
- Liver Neoplasms/metabolism
- Liver Neoplasms/pathology
- Liver Neoplasms/virology
- RNA, Viral/analysis
- RNA, Viral/genetics
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Viral Regulatory and Accessory Proteins
- fas Receptor/metabolism
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Affiliation(s)
- Y M Jin
- Department of Pathology, Ajou University School of Medicine, Suwon, Korea
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36
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Huo TI, Wang XW, Forgues M, Wu CG, Spillare EA, Giannini C, Brechot C, Harris CC. Hepatitis B virus X mutants derived from human hepatocellular carcinoma retain the ability to abrogate p53-induced apoptosis. Oncogene 2001; 20:3620-8. [PMID: 11439325 DOI: 10.1038/sj.onc.1204495] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2000] [Revised: 03/21/2001] [Accepted: 04/02/2001] [Indexed: 01/18/2023]
Abstract
Chronic hepatitis B virus (HBV) infection and the integration of its X gene (HBx) are closely associated with the development of hepatocellular carcinoma (HCC). The integrated HBx frequently is truncated or contains point mutations. Previous studies indicated that these HBx mutants have a diminished co-transactivational activity. We have compared the effects of wild-type (wt) HBx and its naturally occurring mutants derived from human HCCs on transcriptional co-transactivation, apoptosis and interactive effects with p53. We demonstrated that overexpression of mutant, but not wt HBx, is defective in transcriptional co-transactivation of the NF-kappaB-driven luciferase reporter. By using a microinjection technique, the HBx mutants were shown to have an attenuated pro-apoptotic activity. This deficiency may be attributed to multiple mutations in the co-transactivation domain of HBx, that leads to decreased stability of the translated product. However, wt or mutant HBx bind to p53 in vitro and retain their ability to block p53-mediated apoptosis in vivo, which has been implicated as its major tumor suppressor function. The abrogation of p53-mediated apoptosis by integrated HBx mutants may provide a selective clonal advantage for preneoplastic or neoplastic hepatocytes and contribute to hepatocellular carcinogenesis.
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Affiliation(s)
- T I Huo
- Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, MD 20892 USA
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