Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hepatitis B virus (HBV)-encoded transcriptional activator HBV-X protein (HBx) was known to be involved in hepatocarcinogenesis. Hepatocarcinogenesis generally included an active angiogenesis that was mainly considered to be due to a local hypoxia in liver tissues. However, the exact mechanisms of HBx-induced hepatocarcinogenesis were poorly understood. In this study, we examined the role of HBx in the increased angiogenesis and the possible regulating mechanisms of HBx by hypoxia. We demonstrated that HBx stimulated the transcription of vascular endothelial growth factor (VEGF), a potent angiogenic factor, in HBx-stable transfectants. HBx-induced angiogenesis was confirmed by in vivo tumor angiogenesis assay, resulting in that the HBx transfectants increased the formation of new blood vessels compared to the control transfectants. Then, we demonstrated that the expression of HBx was enhanced after incubating HBV-infected hepatoma cells under hypoxia. Moreover, the activity of HBV enhancer 1 (Enh1) was increased when hepatoma cells transfected with the reporter plasmid containing HBV Enh1 were exposed to hypoxic conditions. These results strongly suggest that HBx may play a critical role in the hypoxia-induced angiogenesis through transcriptional activation of VEGF during hepatocarcinogenesis.
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PMID:Human hepatitis B virus X protein is a possible mediator of hypoxia-induced angiogenesis in hepatocarcinogenesis. 1067 26

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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PMID:Hepatitis B virus X protein enhances transcriptional activity of hypoxia-inducible factor-1alpha through activation of mitogen-activated protein kinase pathway. 1285 80

Hepatitis B virus X protein (HBx) is closely involved in the development of hepatocellular carcinoma, a highly vascularized solid tumor. Here we show that HBx increases the transcriptional activity and protein level of hypoxia-inducible factor-1alpha (HIF-1alpha) under both normoxic and hypoxic conditions, and it also stimulates angiogenesis. HBx directly interacted with the bHLH/PAS domain of HIF-1alpha but not with the von Hippel-Lindau protein (pVHL). HBx decreased the binding of pVHL to HIF-1alpha and prevented ubiquitin-dependent degradation of HIF-1alpha. In HBx-transgenic mice, HIF-1alpha and vascular endothelial growth factor were strongly detected in the dysplastic lesion, where HBx was also more highly expressed than in the non-neoplastic region of the liver. An immunohistochemical study showed that microvessels are more abundant in the dysplastic lesion than in the non-neoplastic region. Our data suggest that HBx stabilizes HIF-1alpha and leads to angiogenesis during hepatocarcinogenesis.
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PMID:Hepatitis B virus X protein induces angiogenesis by stabilizing hypoxia-inducible factor-1alpha. 1468 11

Evidence indicates that cyclooxygenase (COX)-2-derived prostaglandins (PGs) contribute to tumor growth by inducing angiogenesis. We investigated the role of COX-2 in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). COX-2 and vascular endothelial growth factor (VEGF) expressions were examined by immunohistochemistry in 24 HBV-associated HCC. Tumor micro-vessel density (MVD) was assessed using CD34 immunohistochemistry. Hep3B HCC cell line, which carries integrated HBV genome, was stably transfected with human COX-2 cDNA. COX-2 and VEGF expressions were determined by Western blot while PG level was determined by ELISA. The effects of PGs on VEGF expression were also investigated. Expression of COX-2 and VEGF in HCC cells were observed in 19 (79%) and 16 (67%) cases, respectively. Well-differentiated HCC expressed COX-2 more strongly than less-differentiated HCC (p<0.001). COX-2 expression was found to correlate with VEGF expression and MVD (p=0.003 and 0.004, respectively). COX-2 overexpressing Hep3B clone had higher VEGF expression as compared to non-COX-2 expressing clone and parental cells. Treatment of the COX-2 overexpressing cells with a COX-2-selective inhibitor, NS-398 (10 microM), decreased PGE2 level and attenuated VEGF expression. Addition of PGE2 (10 microM) and the stable analog of PGI2, carbaprostacyclin (5 microM), to Hep3B cells also increased VEGF expression. Up-regulation of COX-2 correlates with VEGF expression and tumor angiogenesis in HBV-associated HCC. Moreover, COX-2 up-regulates VEGF expression in HCC cells, possibly via PGs production. Selective inhibition of COX-2 may block HCC associated angiogenesis and thus provides a rational approach for treatment of this malignancy.
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PMID:Cyclooxygenase-2 pathway correlates with vascular endothelial growth factor expression and tumor angiogenesis in hepatitis B virus-associated hepatocellular carcinoma. 1501 Aug 22

It has been demonstrated that CD34-positive cells isolated from human peripheral blood differentiate into endothelial cells and contribute to neoangiogenesis in adults. We investigated the role of CD34-positive endothelial cells in liver samples from patients with hepatitis B virus (HBV)-associated chronic liver diseases. Tissue sections were obtained by liver biopsy from 25 patients with HBV-associated chronic liver diseases and were examined by immunohistochemistry using anti-CD34, anti-von Willebrand factor (vWF), and anti-vascular endothelial growth factor (VEGF) antibodies. CD34-positive, but vWF-negative endothelial cells were observed, particularly in the sinusoids and vascular endothelial cells. We counted these cells and expressed the results as a CD34-labeling index (LI). The CD34 LI did not correlate with VEGF expression and the CD34 LI of patients who progressed to hepatocellular carcinoma (HCC) tended to increase compared to those that did not progress to HCC. CD34 LI was an independent risk factor for development of HCC (relative risk, 35.689; P = 0.033). We conclude that CD34-positive endothelial cells in patients with HBV-associated chronic liver diseases might play a role in hepatocarcinogenesis.
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PMID:Expression of CD34-positive sinusoidal endothelial cells in patients with HBV-associated chronic liver diseases. 1525 62

Hepatocellular carcinoma (HCC) is one of the most common cancers and is the leading cause of cancer death in Taiwan. Curative surgery is feasible for only about 30% of patients. Transarterial embolization or chemoembolization (TAE/TACE) has been demonstrated to provide a survival benefit compared with supportive care for HCC patients with adequate liver reserves, tumors confined to the liver, and no evidence of portal vein thrombosis. Percutaneous ethanol injection (PEI) may provide long-term disease control if the extent of liver tumors is limited (3 or less in number and less than 3 cm in diameter). The relative efficacy of TAE/TACE, PEI, and other locoregional treatment modalities, such as radiofrequency ablation or cryosurgery, remains unclear. Radiotherapy has been used mostly as a salvage therapy in combination with other locoregional modalities. Despite the incorporation of 3-dimensional conformal technology, radiation-induced liver injury remains an important problem, especially for patients with hepatitis B-related cirrhosis. Systemic therapy is difficult for HCC because of the underlying cirrhosis and accompanying hypersplenism and peripheral cytopenia. HCC is typically resistant to most cytotoxic agents. Biochemical modulation with high-dose tamoxifen may sensitize HCC cells to doxorubicin-induced apoptosis and improve the clinical response to doxorubicin in patients with advanced HCC. Thalidomide, which inhibits angiogenesis induced by vascular endothelial growth factor and basic fibroblast growth factor, can produce a response in some HCC patients. Future research on drug therapy for HCC will focus on identification of tumor-specific targets.
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PMID:Recent advances in non-surgical treatment for advanced hepatocellular carcinoma. 1531 70

Hepatocellular carcinoma (HCC) is a common cancer in the world due to high prevalence of hepatitis B or C virus infection. Research in recent years has uncovered important molecular pathways involved in development and progression of HCC. Several genetic aberrations and molecular mechanisms responsible for initiation of hepatocarcinogenesis have been identified. Novel biomarkers for HCC are being developed for better detection and prognostication. Alpha-fetoprotein, the conventional marker of HCC, has limited sensitivity and specificity. Serum levels of isoforms of AFP based on differential lectin binding of the glycan moiety appear to be more sensitive and specific than total AFP level in early detection of HCC. The clinical usefulness of other HCC biomarkers such as des-gamma-carboxy prothrombin and glypican-3 are under investigation. HCC is an aggressive tumor with early vascular invasion and metastasis. Studies over the past two decades have elucidated the clinical predictors of outcome, leading to several staging systems for HCC based on clinical parameters. However, the predictive accuracy of clinical staging systems is limited. Recent studies suggested that biological factors may provide additional prognostic information. In particular, gene expression profiling appears to be a promising approach. Study of tumor angiogenesis in HCC reveals that the expression of angiogenic factors such as vascular endothelial growth factor and angiopoietins may also predict prognosis. The elucidation of tumor biology of HCC is of particular importance in the current era of rapid development of anti-cancer molecular targeting agents, which provide hope for an effective systemic therapy for HCC.
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PMID:Biology of hepatocellular carcinoma. 1823 13

The objective of this study was to investigate the expressions of angiogenic factors and elucidate their angiogenic and prognostic roles in hepatocellular carcinoma (HCC) with background of hepatitis B virus (HBV). We evaluated microvessel density (MVD) of HCC, and investigated immunohistochemical expression of vascular endothelial growth factor (VEGF), angiopoietins (Ang-1 and Ang-2), and matrix metalloproteinases-9 (MMP-9) in 67 specimens of surgically resected HCC, which were all positive for hepatitis B surface antigen. We investigated the relationship between their expressions and clinicopathological factors or prognosis. The microvessel density (MVD) of tumor tissue and surrounding normal liver tissue was 93.1 +/- 43.8/mm2 and 30.4 +/- 14.8/mm2, respectively. The MVD of well-differentiated HCC was significantly less than that of poorly differentiated HCC. MVD was positively correlated with VEGF and Ang-2 expression (P = 0.0023 and 0.0265, respectively). There was less tumor recurrence in low Ang-2 and low MMP-9 group than high Ang-2 and/or high MMP-9 group (P = 0.002). In Cox regression model, portal vein thrombus and intrahepatic metastasis was the risk factors of tumor recurrence (P = 0.003 and 0.001, respectively). Our study showed that the expression of VEGF and Ang-2 were positively correlated with MVD. Ang-2 expression and/or MMP-9 expression might be a significant predictive factor for recurrence after resection in HCC patients with the background of HBV.
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PMID:The angiogenic and prognostic implications of VEGF, Ang-1, Ang-2, and MMP-9 for hepatocellular carcinoma with background of hepatitis B virus. 1908 71

To determine the long-term prognosis of hepatocellular carcinoma (HCC) after argon-helium cryoablation and identify the risk factors that predict metastasis and recurrence. A total of 156 patients with hepatitis B-related HCC less than 5 cm in diameter who underwent curative cryoablation were followed up prospectively for tumor metastasis and recurrence. Immunohistochemistry was used to analyze the expression of vascular endothelial growth factor (VEGF). HBV basal core promoter (BCP) and precore mutations were detected by DNA sequence analysis. Post-treatment prognostic factors influencing survival, tumor metastasis and recurrence were assessed by univariate and multivariate analyses. The variables included the expression of VEGF in HCC tissues, clinical and pathologic characteristics of patients, and HBV features (HBV DNA level, HBV genotype, BCP mutation). The median follow-up period of the 156 patients was 37 months (range 8-48 months). The 1-, 2-, and 3-year overall survival rates were 92, 82 and 64%, respectively. The 1-, 2-, and 3-year recurrence-free survival rates were 72, 56 and 43%, respectively. Eighty-five patients (54.5%) had tumor recurrence or metastasis. The multivariate analysis showed that Child-Pugh class and the expression of VEGF in HCC tissues could be used as independent prognostic factors for overall survival. Meanwhile, the expression of VEGF in HCC tissues and HBV BCP mutations were found to be independent prognostic factors for recurrence-free survival. Strong expression of VEGF in HCC tissues and HBV BCP mutations are important risk predictors for recurrence or metastasis of HCC smaller than 5 cm in diameter.
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PMID:Prognostic factors and recurrence of hepatitis B-related hepatocellular carcinoma after argon-helium cryoablation: a prospective study. 1978 86

Concerning the important differences in the ethiopathology of hepatocelular carcinomas (HCC) in humans and dogs, our work describes the expression of epidermal growth factor receptor (EGFr), cytokeratine 19 (CK19), vascular endothelial growth factor (VEGF) and transforming growth factor beta receptor (TGFbeta-r) in tumors arising in both species. Investigation included 25 cases of human and 8 cases of dog tumors. All human cases were noted in cirrhotic livers, while in dogs the tissue adjacent to tumor was not changed. In humans in two cases hepatitis B virus (HBV) and in one case hepatitis C virus (HCV) were determined. Investigation showed lack of TGFbeta-r reaction in six cases of canine HCC, while in humans only one case was negative. In most tumors specific hepatocyte antigen Hepatocyte Paraffin 1 marker (Hep Par 1) was mainly positive with markedly decreased reaction compared to the normal hepatocytes, while cytokeratine 19 for billiary epithelium was negative. The result of our investigation rise the question about the possible role of tumor suppressor gene TGFbeta-r in the development of HCC in dogs and in the same time emphasizes its importance in human diseases.
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PMID:Comparative analysis of hepatocellular carcinoma in men and dogs. 1986 Jan 8


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