Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hepatitis B virus (HBV) nucleocapsid consists of 240 viral core proteins that are arranged in a highly symmetrical structure, HBV replication can only take place inside intact nucleocapsids. In the present study, we investigated whether genetically engineered core mutants can inhibit viral replication by interfering with the formation of intact nucleocapsids. Using the duck hepatitis B virus (DHBV) model, a series of core protein mutants was generated. Polymerase chain reaction-amplified fragments from the bacterial lacZ gene expressing up to 282 amino acids were added either to the amino- or carboxy-terminus of the DHBV core protein. In addition, carboxy-terminal extensions were generated by fusing the DHBV core protein with the DHBV small surface protein or various fragments of the viral polymerase. Finally, the green fluorescent protein (GFP) was fused in-frame to the carboxy-terminus of the DHBV core protein. In this chimeric protein, GFP is still functional and can act as a reporter molecule. The various core protein mutants were tested for their potential antiviral activity by cotransfection with a replication-competent DHBV construct into the avian hepatoma cell line LMH. Carboxy-terminal, but not amino-terminal, DHBV core mutants inhibited DHBV replication by up to 90% at an effector-to-target ratio of 1:10, thus displaying a dominant negative phenotype. Antiviral activity was species-specific and caused by posttranslational interference with viral replication. The DHBV core-GFP fusion protein should be an ideal tool to assess the antiviral potential of dominant negative core proteins in vivo.
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PMID:Inhibition of viral replication by genetically engineered mutants of the duck hepatitis B virus core protein. 869 Mar 95

Hepatitis C virus (HCV) is a major worldwide cause of acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The development of vaccines against HCV have been complicated by the high variability of the envelope region, and it is likely that the cellular immune responses to viral structural proteins may be important for eradicating persistent viral infection. Recently, it was reported that the injection into muscle cells of plasmids encoding viral genes resulted in the generation of strong cellular immune responses. We constructed vectors that express the highly conserved HCV core gene. In this regard, the pHCV 2-2 construct contained the entire HCV core region and pHCV 4-2 contained both the 5' noncoding region and the core gene. Cellular expression of HCV core protein was assessed following transfection into human and murine cell lines, and higher intracellular levels of the 21-kd core protein were observed with pHCV 2-2. These HCV core DNA constructs were used to immunize BALB/c mice and produced low-level anti-HCV core humoral immune responses. To assess cytotoxic T-lymphocyte (CTL) activity generated in vivo, a cloned syngeneic SP2/O myeloma cell line constitutively expressing HCV core protein was established and inoculated into BALB/c mice to produce growth of plasmacytomas. Strong CTL activity was generated because the tumor size and weight in pHCV 2-2-immunized mice were remarkably reduced compared with mice injected with mock DNA. Spontaneous CTL activity was also exhibited by splenocytes in an in vitro cytotoxicity assay. These investigations demonstrate that plasmid constructs expressing HCV core protein generate strong CTL activity, as assessed both in vivo and in vitro, and are promising candidates as antiviral agents.
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PMID:Expression and immune response to hepatitis C virus core DNA-based vaccine constructs. 870 53

The viral load of hepatitis C virus, as reflected by hepatitis C virus viremia, has been shown to have important clinical implications. In this study the hepatitis C virus core protein level in serum was evaluated for the detection and quantification of hepatitis C virus viremia. Hepatitis C virus core protein in serum was detected using a simple and sensitive fluorescent enzyme immunoassay. Hepatitis C virus core protein was quantitated in 100 healthy subjects, 258 patients with hepatitis C virus infection and 108 patients with non-hepatitis-C-virus-related chronic liver diseases. HCV-RNA was determined using the branched DNA (bDNA) assay and reverse-transcription polymerase chain reaction. The detection limit of this fluorescent enzyme immunoassay was found between 10(4) - 10(5) copies/ml HCV-RNA equivalent. There was a good correlation between the core protein and bDNA assay results (p <0.01). Hepatitis C virus core protein was detected in 81% of patients with hepatitis C virus infection (acute hepatitis 4/5, chronic hepatitis 85/104, cirrhosis 64/73 and hepatocellular carcinoma 56/76) but in none of the healthy subjects and patients with non-hepatitis C virus chronic liver diseases. The amount of hepatitis C virus core protein in patients with hepatitis-C-virus-related hepatocellular carcinoma was lower compared to chronic hepatitis and cirrhosis (p <0.05). All 26 patients treated with interferon-alpha showed parallel changes between HCV-RNA and core protein levels. This fluorescent enzyme immunoassay is simple and quick (assay time <3 h) with sensitivity at least matching the bDNA assay. Similar levels of hepatitis C virus core protein were detected in patients with chronic hepatitis and cirrhosis, but patients with hepatocellular carcinoma tended to have a lower level of hepatitis C virus core protein.
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PMID:Simple fluorescent enzyme immunoassay for detection and quantification of hepatitis C viremia. 875 Jan 76

Nucleocapsid assembly in hepadnavirus replication requires selective encapsidation of the pregenomic RNA template and the viral polymerase by the core proteins. It has been shown that an encapsidation signal located at the 5' end of the pregenomic RNA is responsible for its interaction with the polymerase. In the present study, we have shown that a region located at the 3' periphery of the core open reading frame may interact with the viral polymerase in duck hepatitis B virus. By using an in vitro rabbit reticulocyte lysate translation system, we found that interaction of the polymerase with this region resulted in selective suppression of core mRNA translation. Insertion of this putative inhibitory sequence into the CD4 gene also led to a selective inhibition of CD4 mRNA translation in the presence of polymerase. Specific inhibition of core protein synthesis was observed in a chicken hepatoma cell line (LMH) cotransfected with core and polymerase plasmid DNA.
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PMID:Duck hepatitis B virus polymerase acts as a suppressor of core protein translation. 876 10

Three novel monoclonal antibodies (MAbs) were established against a recombinant hepatitis C virus (HCV) core protein derived from cloned genotype 1b HCV cDNA. MAbs C7-50 and C8-59 recognize a conserved linear epitope represented by amino acid residues 21 to 40 of the nucleocapsid protein. MAb C8-48 is directed against a strain-specific conformational epitope located within the first 82 amino acids. A sensitive two-site MAb-based immunoradiometric assay was established using antibodies directed against distinct epitopes on the nucleocapsid protein. Processed 21 kDa core protein was detected by immunoblotting in human hepatocellular carcinoma cell lines and primary adult rat hepatocytes transfected with a cytomegalovirus promoter-driven expression construct. Immunofluorescence microscopy studies revealed a granular and vesicular cytoplasmic staining pattern. MAb C7-50 was used successfully to detect HCV core antigen in chronically infected chimpanzee liver tissue. These MAbs represent important reagents for the study of HCV biology and for the development of immunodiagnostic assays.
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PMID:Characterization of three novel monoclonal antibodies against hepatitis C virus core protein. 880 Dec 83

Infection with the hepatitis C virus (HCV) commonly causes persistent disease, which may lead to cirrhosis and hepatocellular carcinoma. The pathogenesis of HCV infection is not well understood. It is most likely that both viral and host factors contribute to HCV persistence. This review focuses on the host's immune response to HCV in an attempt to present the current knowledge and concepts of the interactions between the virus and the host during HCV infection. Expansion of B lymphocytes and antibody production to virtually any HCV protein can be detected in most infected patients. However, observations in HCV-infected humans as well as experimental infections in chimpanzees suggest that natural HCV infection does not induce protective immunity, and reinfection can readily be demonstrated after inoculation with homologous or independent strains in HCV-seroconverted animals. Nevertheless, the immune system may gain partial control over HCV even in patients with chronic infection, as HCV infection in severely immunocompromised patients runs a particular cholestatic course which may rapidly lead to death from liver failure. Cytotoxic CD8+ T lymphocyte responses to HCV proteins have been characterized in peripheral blood and liver tissue and were found to be remarkably polyclonal and multispecific. Epitopes were identified on all of the putative HCV proteins, although only few major histocompatibility complex molecules were considered restriction elements. Immunoregulation may be particularly important in HCV infection. The HCV core and NS4 proteins appear to be most immunogenic for peripheral blood lymphocytes, and NS4 specific CD4+ lymphocytes are preferentially compartmentalized to the liver. However, there is an inverse relationship between CD4+ lymphocyte responses and antibody levels in infected patients. Furthermore, a strong cellular response to the HCV core protein apparently favors a benign course of infection. This unusual T-B cell relationship may be the consequence of an altered cytokine release during HCV infection. Alternatively, this virus may have found devices that can disturb immunoregulation in infected patients. A better understanding of these immunological mechanisms induced by HCV infection should make it possible to develop more effective strategies for the prevention and treatment of this insidious disease.
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PMID:Immune responses in hepatitis C virus infection. 883 85

The establishment of stable cell lines expressing the hepatitis C virus (HCV) core protein may be important for studies of HCV pathogenesis. Human and mouse cell lines were generated expressing the HCV core protein using expression vectors driven by either the cytomegalovirus (CMV) or elongation factor-1 alpha (EF-1 alpha) promoters. Following transient transfection, HCV core protein was expressed in all cell lines. However, stable human hepatocellular carcinoma (HCC) and murine myeloma cell lines expressing the HCV core protein were only established using constructs driven by the EF-1 alpha promoter. In contrast, stable expression of the hepatitis B virus (HBV) middle envelope protein (MHBs) was obtained successfully in these cell lines using an expression vector driven by the CMV promoter. Inhibitory activity of the first 69 amino acids of the HCV core protein on the CMV promoter was found by using chimeric MHBs/HCV core protein constructs. Growth of cloned cell lines expressing the HCV core protein was slower than that of nonexpressing cell lines. However, morphological changes and cell death were not observed in the stable cell lines expressing HCV core protein. These results indicate that the HCV core protein was not directly cytotoxic to HCC and myeloma cell lines but that specific promoter elements are required to establish stable expression of the nucleocapsid structural protein.
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PMID:Comparison between cytomegalovirus promoter and elongation factor-1 alpha promoter-driven constructs in the establishment of cell lines expressing hepatitis C virus core protein. 902 32

Transgenic mice have been produced that express the hepatitis C virus (HCV) core protein in the liver under the transcriptional control of the mouse major urinary protein promoter. These animals express the full length core protein in cytoplasm of their hepatocytes at levels comparable to those detected in naturally infected patients, without histological or biochemical evidence of liver disease or hepatocellular carcinoma. This contrasts with recent reports that HCV core protein can transform NIH 3T3 cells and cooperates with H-ras to transform primary rat fibroblasts in vitro. Coexpression of HCV core protein in double transgenic mice that replicate the hepatitis B virus (HBV) does not inhibit hepatocellular HBV gene expression or replication, contrary to reports that it inhibits HBV replication in HuH-7 cells after transient transfection in vitro. We have also produced transgenic mice in which a C-terminally truncated (aa384-715) glycosylated HCV E2 protein is expressed in the liver under the transcriptional control of the mouse albumin promoter. Despite the high level expression of HCV E2 protein, no evidence of liver disease was detected in these animals. These results suggest that the HCV core and E2 proteins are not cytopathic for the hepatocyte in vivo, and they represent an initial step in the development of a small animal model of HCV immunopathology.
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PMID:Hepatitis C virus core and E2 protein expression in transgenic mice. 904 25

We investigated the association between hepatocellular carcinoma (HCC) and the genomic characteristics of the hepatitis C virus (HCV) isolated from residents of the inshore region of the Yangtze River, an area that has one of the highest incidence of HCC in China. We determined the genomic heterogeneity of HCV, and the sequence divergence of the HCV core gene in individuals with chronic hepatitis and HCC. HCV genotype II was predominant among these isolates, which were homologous to other Chinese and Japanese HCV isolates. The rate of nucleotide substitutions in the core gene was significantly greater for isolates from HCC patients than for those from individuals with chronic hepatitis. The nucleotide substitutions were unevenly scattered along the core gene; a cluster of missense mutations was apparent in the region encoding the second hydrophilic domain of the core protein. The rate of occurrence of missense mutations per nucleotide substitution was significantly greater in this clustering variable region (CVR) of the core gene than in the remaining core gene sequence. These observations suggest that mutations in the CVR may be involved in the pathogenesis of chronic HCV infection during hepatocellular carcinogenesis.
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PMID:Mutations in a hydrophilic part of the core gene of hepatitis C virus in patients with hepatocellular carcinoma in China. 905 95

Our previous results have suggested that the putative core protein of hepatitis C virus (HCV) transcriptionally regulates cellular and viral genes, inhibits cisplatin and c-myc-mediated apoptotic cell death under certain conditions, and transforms primary rat embryo fibroblast cells with a cooperative oncogene. Because HCV appears to cause hepatocellular carcinoma, we evaluated the regulatory role of the HCV core protein on p53, a well known tumor suppressor gene, by an in vitro transfection assay. HCV core protein repressed transcriptional activity of the p53 promoter when tested separately in COS7 and HeLa cells. Deletion mutational analysis of the HCV core gene indicated that the regulatory domain involved in the repression of p53 transcriptional activity is located around amino acid residues 80-122 encompassing a putative DNA binding motif and two major phosphorylation sites. Results from this study suggest that the putative core protein may have an important biological role in the promotion of cell growth by repressing p53 transcription, and this appears to be consistent with certain earlier observations about HCV core moving into the nucleus.
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PMID:Transcriptional repression of p53 promoter by hepatitis C virus core protein. 911 Sep 85


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