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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 10 kb genomic DNA fragment derived from a human primary liver cell carcinoma (PLC) and containing integrated hepatitis B virus (HBV) DNA was cloned and analysed. Physical mapping showed the viral DNA to comprise a linear sequence of at least 2.8 kb (87%) of the HBV genome and to be of the adr subtype. Integration appeared to have occurred in the region of the viral genome spanning the cohesive ends. The cellular flanking DNA sequences to one side of the integrated viral DNA contained repeats of the Alu family. The finding of no apparent rearrangements of the integrated HBV DNA sequences in this clone is in contrast to the situation in the huSP and PLC/PRF/5 PLC cell lines in which the integrated viral DNA sequences are greatly rearranged and suggests that such rearrangements may be atypical of solid PLCs.
J Gen Virol 1986 Apr
PMID:Cloning and analysis of integrated hepatitis B virus DNA of the adr subtype derived from a human primary liver cell carcinoma. 300 65

In this paper the kinetics of hepatitis B virus (HBV) gene expression were investigated in natural and experimentally transfected cell systems. These systems included four human hepatocellular carcinoma cell lines containing HBV DNA (TONG/PHC, HEp 3B2, PLC/PRF/5 and HA22T/VGH) as well as a mouse and a rat cell line both experimentally transfected with HBV DNA. Comparative results on the kinetics of hepatitis B surface antigen in these cell systems suggested that the S gene in the integrated state is expressed at different levels. No human cell line derived from HBV-associated hepatocellular carcinoma produced hepatitis B e antigen (HBeAg) when medium was concentrated by ultrafiltration. In distinct contrast, the two experimentally transfected cell systems produced e antigen at different levels. When all HBV-containing cell lines were grown as tumours in nude mice, no HBeAg was detected in the serum of these mice inoculated with human hepatocellular carcinoma cell lines, in the tumour homogenates, or in the tumour-derived lines, whereas e antigen was expressed both in vivo and in vitro in the experimentally transfected cell lines. These observations indicate that C gene expression is restricted to transfected cell cultures and this suggests a distinct difference in the mechanisms of HBV gene expression between the two types of in vitro model systems.
J Gen Virol 1986 Nov
PMID:Comparative expression of hepatitis B virus antigens in several cell model systems. 302 26

The human hepatoma cell line PLC/PRF/5 is persistently infected with hepatitis B virus. Cells cultured in vitro are known to produce the virus surface antigen but not be other structural virus proteins, the core and the e antigen. It is shown here that expression of the core antigen gene was inducible by growing the cells as a nude mouse tumour. The buoyant density in CsCl (1.31 to 1.32 g/ml) of core or e antigen produced in the tumours was very similar to that of virus core particles. Expression of the core antigen gene was shunt off by culture in vitro of core or e antigen-producing nude mouse tumour cells and induced again by subsequent passage of cells in the nude mouse. The experimental system thus allows studies on the regulation of expression of the core antigen gene.
J Gen Virol 1984 Aug
PMID:Expression of hepatitis B virus core antigen gene is induced in human hepatoma cells by their growth in nude mice. 608 28

Hepatitis B virus (HBV) DNA was found to be integrated into seven sites in the DNA of the PLC/PRF/5 hepatoma cell line as determined by digestion with the restriction endonuclease HindIII which does not cut through the viral genome. The integration pattern was stable in the cell line, in tumours induced in athymic mice by this line and in cell lines derived from such tumours. Syntheses of hepatitis B surface antigen and alphafoetoprotein were maintained in the induced tumours and derived cell lines. A defective HBV DNA molecule (approx. 2.8 kilobase pairs) appears to be integrated in a head-to-tail tandem arrangement and it is proposed that such defective molecules may be involved in the process of neoplastic transformation by HBV.
J Gen Virol 1983 Oct
PMID:Defective hepatitis B virus DNA molecules detected in a stable integration pattern in a hepatoma cell line, and in induced tumours and derived cell lines. 619 51

Cultures of two human hepatoma cell lines were examined for expression of hepatitis B virus surface antigen (HBsAg). The PLC/PRF/5 cells secreted HBsAg continuously into the culture medium, whereas Mahlavu cells did not secrete the antigen. However, cytoplasmic antigen was detected in a low percentage (less than 5%) of the Mahlavu cells. The expression of HBsAg also was assayed in cultures treated wtih dexamethasone (DXM), 5-iodo-2'-deoxyuridine (IdUrd), or both. The results demonstrated that: (i) DXM stimulated secretion of HBsAg by PLC/PRF/5 cells but not by Mahlavu cells; (ii) the percentage of Mahlavu cells expressing cytoplasmic HBsAg was not increased in any cultures if the medium was replaced at 24 t0 48 h intervals but was increased approx. fivefold within 4 days in cultures treated with DXM or IdUrd/DXM if the medium was not changed. However, no increase was noted in the intensity of the immunoperoxidase stain of PLC/PRF/5 cells that expressed cytoplasmic antigen in any DXM cultures; (iii) HBsAg expression was stimulated to a lesser extent in IdUrd/DXM cultures than in DXM cultures and was not enhanced in IdUrd cultures. Thus, DXM enhanced secretion of HBsAg by PLC/PRF/5 cells within 24 h and, after a delay, enhanced expression of cytoplasmic antigen by Mahlavu cells. However, antigen secretion by Mahlavu cells evidently was blocked.
J Gen Virol 1981 Mar
PMID:Induction of hepatitis B surface antigen in human hepatoma-derived cell lines. 626 37

Replication of hepatitis A virus (HAV) in the human hepatoma-derived PLC/PRF/5 cell line was neither inhibited in the presence of various concentrations of guanidine or D-2-(alpha-hydroxybenzyl)benzimidazole (D-HBB), nor were the two chemicals effective in combination. Under identical conditions, however, replication of poliovirus type 1 was inhibited. Tracer experiments with radiolabelled guanidine and D-HBB also furnished no evidence that the two antiviral substances were metabolized gradually to inactive derivatives in PLC/PRF/5 cells. Therefore, it is concluded that resistance to the action of guanidine and D-HBB is an inherent characteristic of HAV. However, the insensitivity of HAV to these drugs does not exclude the virus from the family of picornaviruses.
J Gen Virol 1982 Jul
PMID:Failure of guanidine and 2-(alpha-hydroxybenzyl)benzimidazole to inhibit replication of hepatitis A virus in vitro. 628 46

Recently, we have identified and purified the integrated and proviral DNA sequences specific for two endogenous rat type C leukaemia helper viruses: WR-RaLV which originated from a fibrosarcoma induced in a feral rat and RHHV from the cell line HTC-H1 which originated from a Buffalo rat hepatoma. The rat leukaemia helper virus DNA sequences have previously been shown to be 8.4 to 8.8 kilobases (kb) in size. In this communication, we report the molecular cloning of the 8.8 kb DNA of RHHV by ligation at the BamHI site of the vector pBR322, cultured in an Escherichia coli RR1 host. After screening 5750 clones for ampicillin resistance and tetracycline sensitivity and testing by colony hybridization using 32P-labelled RHHV cDNA, four clones were isolated, two of which carried the total 8.8 kb DNA. A detailed restriction endonuclease map of the cloned RHHV DNA was deduced by sequential digestions of either 3'- or 5'-labelled DNA. Of the 14 restriction enzymes tested, EcoRI, BamHI, PstI, KpnI, TaqI, PvuII and SmaI gave informative cleavage patterns. At least two copies of long terminal repeated sequences (LTR) flanking the 3' and 5' termini of the proviral DNA were identified by TaqI and PstI cleavages. LTR in the rat endogenous leukaemia helper virus DNA measured 780 +/- 20 nucleotides in length. The genetic information encoded by the cloned DNA was also analysed by hybridization selection of RHHV mRNA, which was then used in cell-free protein synthesis in a rabbit reticulocyte lysate system. Essentially all major RaLV-specific proteins precipitable by anti-RaLV serum were synthesized in vitro, confirming that the RHHV genomic DNA was successfully cloned with little fidelity loss or scrambling of the genetic information.
J Gen Virol 1982 Nov
PMID:Molecular cloning of the endogenous rat C-type helper virus DNA sequence: structural organization and functional analysis of some restricted DNA fragments. 629 30

Immunochemical and immunocytochemical techniques have been used to characterize viral glycoproteins and endogenous rat leukaemia viruses (RaLV) produced both by Novikoff hepatocellular carcinoma cells and spontaneously transformed Wistar rat embryo cells (WRC). Results from immunocytochemical analysis demonstrated that RaLV produced by Novikoff and WRC cells could be distinguished by their unique patterns of reactivity with xenoantisera raised against virus particles or viral glycoproteins. This differential labelling was unexpected since all the antisera tested had been shown by immunoprecipitation and immunodepletion analysis to be reactive with viral glycoproteins expressed on the cell surface. Since no significant differences in cell surface-associated viral glycoproteins and those shed from the cell surface were detected by pulse iodination analysis, it was concluded that the apparent discrepancy between immunoferritin labelling and immunoprecipitation analysis resulted from differences in antigen accessibility on intact virions caused by structural differences in the viral glycoproteins expressed on Novikoff and WRC cells. This conclusion was supported by results from ferritin-lectin labelling, affinity chromatography and neuraminidase digestion studies which demonstrated differences in the saccharide moieties on both virion and cell surface-associated viral glycoproteins. Further evidence of structural differences was provided by limited digestion with trypsin and V8 protease of the Mr 64 000 (Nov gp64) and Mr 68 000 (WRC gp68) viral glycoproteins immunoprecipitated from Novikoff and WRC cells, respectively, with either monospecific anti-Rauscher murine leukaemia virus anti-gp70 serum or monospecific antiserum against Nov gp64 (anti-gp64). Results from digestion studies showed that all the major cleavage fragments from WRC gp68 were of higher molecular weight than their Nov gp64-derived counterparts. Evidence that Nov gp64 and WRC gp68 both share structural homology with other murine viral gp70s was suggested by results from immunoprecipitation analysis with anti-gp70 and anti-gp64 sera under reducing and non-reducing conditions which demonstrated the presence of an interchain disulphide bond in both glycoproteins and showed that at least some of these molecules exist on the cell surface as disulphide-linked heterodimers of Mr 78 000 and 82 000.
J Gen Virol 1984 Apr
PMID:Structural differences in envelope glycoproteins associated with rat leukaemia virus produced by Novikoff hepatocellular carcinoma and spontaneously transformed Wistar rat embryo cells. 636 46

The interactions of naturally occurring polyamines: putrescine, spermidine and spermine, with anticancer bis-guanylhydrazones: methylglyoxal-bis(guanylhydrazone) (MGBG) and 4,4'-diacetyldiphenylurea-bis(guanylhydrazone) (DDUG) were investigated at the level of mitochondrial membrane. The effects of bis-guanylhydrazones on intact rat liver mitochondria were readily prevented or reversed by polyamines and these interactions were also affected by the mitochondrial transmembrane potential. Magnesium cations enhanced the protective action of polyamines. The data indicate that competition exists between the essential anticancer bis(guanylhydrazone) and polyamines for low affinity negatively charged binding sites at the outer surface of inner mitochondrial membrane. The study of drug interactions was extended to the level of isolated tumor mitochondria from rat HTC hepatoma and murine L1210 leukemia cells. A complicated pattern of interactions between the anticancer bis-guanylhydrazones and phenethylbiguanide was obtained.
Gen Pharmacol 1983
PMID:Interactions between bis(guanylhydrazones) and polyamines in isolated mitochondria. 668 8

The permeability coefficients of Novikoff hepatoma ascites cell membranes for tritiated water (3HHO) and for a homologous series of monohydric alcohols (methanol through hexanol) were deduced from linear diffusion coefficients by means of a series-parallel pathway model (Redwood et al. (1974) J. Gen. Physiol. 64, 706-729). Membrane permeability coefficients for 3HHO at 20, 30 and 37 degrees C were (all x 10(-5)) 97, 125, and 163 cm . s-1, respectively, and were significantly smaller than the corresponding values for the alcohols tested. In the alcohols series, ethanol had the lowest permeability coefficient 198 x 10(-5) cm . s-1 at 20 degrees C. The apparent activation energy for water permeation was 6.7 +/- 1.9 S.E. kcal . mol-1. The apparent membrane diffusion coefficients for the alcohols were a complex function of molecular properties with less diffusional membrane resistance to the alcohols in the middle of the homologous series than would have been expected on the basis of oil-water partitioning or molar volume considerations. The conventional parallel aqueous lipophilic pathway model is not consistent with the present data which can be interpreted by consideration of parallel lipophilic pathways through the Novikoff hepatoma cell membrane.
 ...
PMID:Permeability of Novikoff hepatoma cells to water and monohydric alcohols. 722 79


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