Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatocellular carcinomas in woodchuck were characterized for woodchuck hepatitis virus integration near c-myc oncogene. In one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. In a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mRNA. These results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. From a comparison of a single hepatitis B virus (HBV) integration site in a human hepatoma with the corresponding unoccupied site have shown HBV DNA insertion in a putative cellular exon. This exon presented striking similarity to the DNA-binding domain of the thyroid/steroid hormones receptors. The corresponding cDNA has been isolated (hap gene) a shown to encode the retinoic acid receptor. It is most probable that consequent to HBV insertion, has became inappropriately expressed as an altered chimaeric gene retinoic acid receptor, thus contributing to the cell transformation. As for woodchuck these results strongly support the possibility that HBV may play a direct role in liver carcinogenesis by insertional mutagenesis.
 ...
PMID:[Hepatitis B virus and hepatocellular carcinoma]. 165 Jun 25

Hepatocellular carcinoma in woodchuck were characterized for woodchuck hepatitis virus integration nea c-myc oncogene. In one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. In a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mRNA. These results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. From a comparison of a single hepatitis B virus (HBV) integration site in a human hepatoma with the corresponding unoccupied site have shown HBV DNA insertion in a putative cellular exon. This exon presented striking similarity to the DNA-binding domain of the thyroid/steriod hormones receptors. The corresponding cDNA has been isolated (hap gene) as shown to encode the retinoic acid receptor. It is most probable that consequent to HBV insertion, hap gene became inappropriately expressed as an altered chimaeric gene retinoic acid receptor, thus contributing to the cell transformation. As for woodchuck these results strongly support the possibility that HBV, may play a direct role in liver carcinogenesis by insertional mutagenesis.
 ...
PMID:[Hepatitis B virus and hepatocellular carcinoma]. 177 42

The proto-oncogene c-myc has been implicated in the formation of primary liver tumors in hepatitis virus-infected woodchucks. In one of these tumors, a DNA rearrangement placed the truncated c-myc gene downstream of a cellular sequence (hcr) in a head-to-tail configuration resulting in 50-fold enhanced levels of c-myc transcripts. Analysis of the tumor-specific c-myc RNA now demonstrates that transformed liver cells produce fused hcr/myc transcripts initiated from the hcr promoter and extending into c-myc coding sequences by differential splicing mechanisms. In phase fusion of the reading frames of both genes might result in the translation of the hcr/myc 2.0 kb RNA into a hybrid protein that would differ from the normal woodchuck c-myc gene product by 22 additional hcr amino acids at its amino-terminus. The production of inappropriate levels of modified or normal myc-encoded proteins is probably involved in the malignant process.
 ...
PMID:Fused transcripts of c-myc and a new cellular locus, hcr in a primary liver tumor. 264 11

Two hepatocellular carcinomas, induced in woodchucks chronically infected with woodchuck hepatitis virus, were characterized for viral integration near c-myc and alterations of c-myc expression. In one tumor, viral integration within the untranslated region of c-myc exon 3 resulted in overexpression of a long c-myc viral cotranscript. In the second tumor, a single insertion of highly rearranged viral sequences 600 bp upstream of c-myc exon 1 was associated with increased levels of normal c-myc mRNA. In both cases, viral enhancer insertion and disruption of normal c-myc transcriptional or posttranscriptional control appear to be involved in c-myc activation. These results demonstrate that integration of woodchuck hepatitis virus near a cellular proto-oncogene, as in several retroviral models, can contribute to the genesis of liver tumors.
 ...
PMID:Activation of c-myc by woodchuck hepatitis virus insertion in hepatocellular carcinoma. 318 Feb 23

We have studied the DNA binding activities of transcription factors in the liver of Long-Evans Cinnamon (LEC) rats, an animal model of Wilson's disease. Owing to a genetic defect, this strain of rats accumulates excessive copper in the liver and develops severe hepatitis and hepatocellular carcinoma. We found that the DNA binding activity of the serum response factor (SRF) was higher in the liver of LEC rats (approximately 2-fold) than in that of Wistar rats. There was a close correlation between the intensity of the activity and the concentrations of copper in the nuclear protein. The DNA binding activity of Sp1, on the other hand, showed similar levels in both LEC and Wistar rats. SRF may play an important role in the development of hepatocellular carcinoma in LEC rats by mediating the proto-oncogene c-fos induction. We suggest that the copper in nuclear protein may be involved in the activation of SRF.
 ...
PMID:Activation of serum response factor in the liver of Long-Evans Cinnamon (LEC) rat. 957 Mar 63

The proto-oncogene product bcl-2 is known to inhibit apoptotic cell death, and its dysregulation might play a critical role in the development of autoimmune disease. To elucidate the role of bcl-2 in autoimmune hepatitis (AIH), its expression in peripheral blood mononuclear cells (PBMC) and in liver-infiltrating lymphocytes (LIL) was investigated. Increased bcl-2 expression in PBMC was found in AIH patients compared with that in chronic hepatitis C (CHC) patients and in healthy controls. The level of bcl-2 expression significantly correlated with serum ALT level. Further analysis showed that CD4+ T cells are enriched in bcl-2-expressing PBMC. To characterize the Th1/Th2 profile of bcl-2-expressing CD4+ T cells, intracellular interferon-gamma (IFN-gamma) and IL-4 were analysed. The results revealed that most of the bcl-2-expressing cells were found to be IFN-gamma-secreting Th1 cells. In three patients for whom their clinical courses could be followed, bcl-2 expression was decreased after the initiation of immunosuppressive therapy with corticosteroids. However, the level of IFN-gamma + cells was not altered. Immunohistochemical analysis also showed that large amounts of bcl-2+ cells were observed in periportal area in the liver. In conclusion, bcl-2-expressing cells were shown to be increased in peripheral blood and liver in AIH and the bcl-2 product was expressed mainly in CD4+ Th1-type cells, suggesting that these cells might promote the cellular immune response and contribute to the development of hepatitis and hepatocellular damage in AIH.
 ...
PMID:Increased bcl-2 expression in lymphocytes and its association with hepatocellular damage in patients with autoimmune hepatitis. 1020 18

In the search for specific chromosomal alterations in human hepatocellular carcinomas (HCC), we analyzed two new HCC cell lines and identified nonrandom changes by combined G-banding and fluorescence in situ hybridization (FISH). Cell line 7703 was established from an HCC deriving from a patient in the Qidong region of China, where the incidence of HCC is very high and is associated with hepatitis-B virus infection and exposure to aflatoxin. This line has a highly rearranged karyotype eliciting complex rearrangements involving the majority of chromosomes. The second line, SK-Hep-1, derived from a liver adenocarcinoma, is less heterogeneous, having few altered chromosomes. We have characterized the majority of structural and numerical alterations and identified in both lines unbalanced translocations with the breakpoints nonrandomly involving regions 1p36 and 3p14 and gain of chromosome 6p and 8q. While gain of 6p and 8q are recurrent in HCC, translocations of 1p and 3p are described for the first time. Damage and recombination at the breakpoint sites on chromosomes 1 and 3 might have resulted in activation of proto-oncogene, formation of new oncogenic chimeric genes, or loss of tumor suppressor genes.
 ...
PMID:Nonrandom breakpoints of unbalanced chromosome translocations in human hepatocellular carcinoma cell lines. 1032 89

Long-Evans Cinnamon (LEC) rats develop severe hepatitis and subsequent hepatoma with excess accumulation of copper in the liver with increasing age. Lipids extracted from the LEC rat liver membrane were studied using FT-IR spectroscopy and an HPLC technique at the stages of pre-hepatitis and hepatitis, i.e. at 10 and 16 weeks of age, respectively. The 10-week-old rats exhibited an IR spectrum characteristic of a phosphatidylcholine and phosphatidylethanolamine mixture with a ratio of 2:1. The 16-week-old rats developed new absorption bands at 1161 and 1070 cm(-1), which were assigned to the spectra of triglyceride, neutral lipid, and diacylglycerol, an endogenous activator of protein kinase C, respectively. The diacylglycerol was estimated to amount to ca. 10% (w/w) of phospholipid extract by comparing the spectrum with those of model compounds. This was confirmed using an HPLC assay. Previously, we found that a serum response factor is activated by copper in the LEC rat liver, and suggested that it must mediate proto-oncogene c-fos induction. The results obtained here suggest that accumulation of diacylglycerol plays an important role in development of hepatoma in LEC rats by mediating proto-oncogene c-fos induction.
 ...
PMID:Accumulation of diacylglycerol in the liver membrane of the Long-Evans Cinnamon (LEC) rat with hepatitis: FT-IR spectroscopic and HPLC detection. 1076 18

Woodchuck hepatitis virus (WHV) and the woodchuck (Marmota monax) are models for hepatocellular carcinoma (HCC) induced by hepatitis B virus (HBV). In woodchuck liver tumors, the N-myc2 proto-oncogene is frequently activated by WHV integration either close to the gene or in the b3n and win downstream loci, located 10 and 150 kb from N-myc2, respectively. A scaffold/matrix attachment region (S/MAR) regulative element was shown to be in b3n, possibly mediating activation of the upstream N-myc2 gene upon WHV integration. To investigate if S/MAR elements are in win too, a 17-kb DNA fragment corresponding to the major region of WHV insertion in this locus was cloned and sequenced. Overlapping subcloned fragments spanning candidate S/MARs predicted by sequence analysis were tested by standard in vitro binding assays. Results showed the presence of two S/MAR elements in win. The distribution of previously described WHV insertions relative to the S/MARs reinforces the hypothesis that S/MARs nearby distal WHV insertions might be involved in long-range activation of N-myc2.
 ...
PMID:The win locus involved in activation of the distal N-myc2 gene upon WHV integration in woodchuck liver tumors harbors S/MAR elements. 1547 69

The principal cause of human liver cancer is infection with hepatitis viruses B and C, but tumor progression is fueled by ensuing perturbations that confer gain of function on proto-oncogenes or loss of function on tumor suppressor genes. Frequent among these perturbations is overexpression of the proto-oncogene MET. We have modeled the pathogenesis of liver tumors by expressing conditional transgenes of MET in the hepatocytes of inbred mice. The response to the MET transgene varied with both the magnitude and timing of its expression but included hyperplasia of hepatic progenitor cells, as well as benign and malignant tumors that display both phenotypic and genotypic resemblances to human counterparts. The results reveal MET to be a crucial switch in the development of the liver; dramatize how different cellular compartments within a developmental lineage can give rise to distinctive tumor stem cells; delineate rules of tumor progression; provide evidence that the experimental tumors in mice are authentic models for human tumors; and support a role for MET in the genesis of human liver tumors. The models should be useful in elucidating the mechanisms of tumorigenesis and in the preclinical testing of new therapeutics.
 ...
PMID:Genomic progression in mouse models for liver tumors. 1686 57


1