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 effects of hormones and cytokines on angiotensinogen production were studied in primary cultured rat hepatocytes. The basal secretion of angiotensinogen decreased during culture. The addition of dexamethasone and (Bu)2cAMP completely prevented this decrease. Angiotensinogen secretion by freshly plated hepatocytes was slightly increased in response to dexamethasone, but after 24 h in culture, hepatocytes no longer responded to dexamethasone alone. When hepatocytes were treated with (Bu)2cAMP, glucagon, or forskolin, angiotensinogen secretion increased in response to dexamethasone in a concentration-dependent manner. 17 beta-Estradiol and T3 failed to stimulate angiotensinogen secretion in either the presence or absence of (Bu)2cAMP. Interleukin-6 (IL-6) exhibited a stimulatory activity on angiotensinogen secretion, which was dependent on the presence of dexamethasone, whereas IL-1 and tumor necrosis factor had no effect in either the presence or absence of dexamethasone and/or (Bu)2cAMP. Unlike primary cultured hepatocytes, angiotensinogen secretion by rat hepatoma H4IIEC3 cells increased in response to dexamethasone alone. This increase was not enhanced by (Bu)2cAMP, but was enhanced by IL-6. Thus, in primary cultures of rat hepatocytes, neither glucocorticoid, cAMP, nor IL-6 alone stimulated angiotensinogen production, but a combination of glucocorticoid and cAMP or of glucocorticoid and IL-6 exhibited a stimulatory activity on angiotensinogen production. These results suggest that angiotensinogen production in the liver is synergistically regulated by these factors, whereas the hepatoma cell line H4IIEC3 lacks the regulatory mechanism of cAMP on glucocorticoid-induced angiotensinogen production.
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PMID:Stimulation of angiotensinogen production in primary cultures of rat hepatocytes by glucocorticoid, cyclic adenosine 3',5'-monophosphate, and interleukin-6. 131 Dec 38

Effects of several cytokines on des-gamma-carboxy prothrombin (PIVKA II) synthesis in human hepatoma cells were investigated to know the process of PIVKA II production during a liver allograft rejection. Human recombinant interleukin-6 (IL-6) significantly stimulated the PIVKA II synthesis without any influence on the cell proliferation. The effect was almost completely neutralized by the specific anti-IL-6 antibody. Neither tumor necrosis factor (TNF), interleukin-1 (IL-1) nor interferon-gamma (IFN-gamma) had such a stimulative effect. IL-6 appears to stimulate PIVKA II production, and would be a candidate of factors that enhance the production of PIVKA II during a liver allograft rejection.
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PMID:The effect of IL-6 on the des-gamma-carboxy prothrombin synthesis in human hepatoma cells. 133 90

C4b-binding protein (C4BP) is involved in the fluid-phase regulation of the classical pathway of complement. During an acute-phase response, we have shown that hepatic levels of murine C4BP mRNA are elevated 2.5-fold while rat liver C4BP gene expression exhibits a 4-fold induction. Furthermore, a survey of different mouse tissues showed that during acute inflammation C4BP gene expression was confined to the liver. To gain a better understanding of the acute-phase regulation of C4BP gene expression we utilized the rat hepatoma cell line FAO in which tumor necrosis factor-alpha (TNF-alpha) produced a 2.7-fold induction of C4BP mRNA levels. In the absence of TNF-alpha, interleukin-1 alpha (IL-1 alpha) and interleukin-6 (IL-6) had little effect on C4BP gene expression but when all three cytokines were used together a synergistic 4-fold induction of C4BP mRNA levels was observed. In contrast the synthetic glucocorticoid dexamethasone inhibited TNF-alpha-induced C4BP gene expression. Cycloheximide-mediated inhibition of inducible C4BP gene expression demonstrated the requirement for ongoing protein synthesis. Rapid induction of C4BP mRNA levels by TNF-alpha and IL-6 (within 1 h) and the observation that stimulation was inhibited by actinomycin D provided evidence that regulation of C4BP gene expression during the acute-phase response is regulated at the transcriptional level. Isolation of a genomic clone extending into the 5' regulatory region of the rat C4BP gene enabled us to identify the major transcriptional start site and putative response elements through which TNF-alpha, IL-6, IL-1 alpha, and dexamethasone may exert their effects on C4BP gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of C4b-binding protein gene expression by the acute-phase mediators tumor necrosis factor-alpha, interleukin-6, and interleukin-1. 133 86

The decreased synthesis of hepatic phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme of gluconeogenesis, that occurs during endotoxemia was shown previously in rats to occur at the transcriptional level. In the current study, the exogenous administration of human recombinant tumor necrosis factor (TNF), a proximal mediator of endotoxic shock, reduced the PEPCK transcription rate, mRNAPEPCK levels, and PEPCK enzyme activity in a time- and dose-dependent manner in CD-1 mice. Comparable amounts of circulating TNF were measured in mice 2 h after injection of human recombinant TNF (10(5) U) or a 50% lethal dose of Escherichia coli endotoxin (20 mg/kg). Direct action of TNF to decrease the PEPCK transcription rate was confirmed in vitro with H-4-II-E Reuber hepatoma cells, in which a dose-dependent inhibition of PEPCK transcription was observed with 1 to 100 U of TNF per ml. A role for TNF-elicited changes in PEPCK gene expression during endotoxemia was confirmed by the protective effect of rabbit polyclonal antibodies to recombinant murine TNF. C57BL/6 mice passively immunized with anti-TNF 4 h prior to endotoxin challenge exhibited normal PEPCK enzyme activity. Neutralization of circulating TNF with anti-TNF failed, however, to prevent the hypoglycemia commonly observed during endotoxemia, suggesting the participation of other mediators. Anti-TNF treatment reduced circulating interleukins 1 and 6 at 3 and 6 h after endotoxin treatment, respectively. These results suggest that during endotoxemia, the development of hypoglycemia is multifaceted and that several cytokines are most likely involved. The findings from the Reuber hepatoma cell model afford an opportunity in future work to map putative cytokine response elements in the PEPCK promoter responsible for perturbed hormonal regulation of the gene during endotoxemia.
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PMID:Identification of tumor necrosis factor as a transcriptional regulator of the phosphoenolpyruvate carboxykinase gene following endotoxin treatment of mice. 139 16

The effects of tumor necrosis factor-alpha (TNF-alpha) on DNA synthesis in AH66 rat hepatoma cells and rat hepatocytes were analysed by means of [3H]thymidine incorporation. DNA synthesis in AH66 cells was suppressed when AH66 cells were directly incubated with TNF-alpha. When primary culture of rat Kupffer cells was incubated with hepatocyte conditioned media pretreated with TNF-alpha (0-200 U/ml), and AH66 cells were then treated with these hepatocyte/Kupffer cell-conditioned media, TNF-alpha used in the pretreatment caused a dose-dependent increase in DNA synthesis in AH66 cells with a maximum effect amounting to a more than 10-fold increase. In contrast, DNA synthesis in primary culture of rat hepatocytes was not stimulated by the TNF-alpha-pretreated hepatocyte/Kupffer cell conditioned media. These results suggest that TNF-alpha-mediated hepatocyte-Kupffer cell interaction selectively promotes proliferation of rat hepatoma cells.
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PMID:Enhanced DNA synthesis in rat hepatoma cells by conditioned media from Kupffer cells incubated with supernatants of tumor necrosis factor-alpha-pretreated hepatocytes. 156 92

Synergistic enhancement of anti-tumor effects through the combined use of natural human interferon-alpha (nHuIFN-alpha) and natural human tumor necrosis factor-alpha (nHuTNF-alpha) enabled us to decrease the effective dose of each cytokine and consequently to reduce side effects. One hundred and twenty patients with advanced or recurrent solid cancer were entered in the trial from April 1985 to January 1988, of whom 112 patients were evaluable. A mixture of nHuINF-alpha and nHuTNF-alpha was injected intravenously as the maintenance dose 1 x 10(6)U or more/day for over 8 weeks. There was no response in 40 patients injected with the maintenance dose of 1 x 10(6)U/day, but of 72 patients receiving more than 2 x 10(6)U/day (10 micrograms of nHuIFN-alpha and 3 micrograms of nHuTNF-alpha), 4 had complete responses, 10 had partial responses, and 4 had minor responses. The overall response rate was 12.5% (14/112) and the rate was 19.5% in 72 patients with more than 2 x 10(6)U/day. Positive responses were as follows: hepatoma 3/8), renal cell cancer (4/11), breast cancer (4/17), ovarian cancer (1/2), malignant thymoma (1/1) and liposarcoma (1/1). Serious adverse effects like hypotension, oliguria and severe hepatobiliary toxicity were never experienced. The effective and adequate dose of the mixed preparation was considered 2 to 4 x 10(6)U/day/body.
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PMID:Early phase II study of interferon-alpha and tumor necrosis factor-alpha combination in patients with advanced cancer. 157 56

We investigated the gene expression of the alpha chain of C4b-binding protein (C4bp alpha) in a variety of tissues, and in liver cell and hepatoma lines. C4bp alpha mRNA was detected in the liver, but not in the other tissues examined. The constitutive gene expression of C4bp alpha by a hepatoma line, HepG2, was significantly augmented by treatment with monocyte-conditioned medium (MoCM), 12-O-tetradecanoylphorbol-13-acetate (TPA), interleukin-6 (IL6) and tumor necrosis factor (TNF) but not by a calcium ionophore (A23187) or interleukin-1 beta (IL1 beta).
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PMID:Interleukin 6 and tumor necrosis factor fully activate liver-specific gene expression of the alpha chain of C4b-binding protein. 165 65

We have studied the effect of interleukin-6 (IL-6) on the binding of tumor necrosis factor (TNF) to various cell lines. A significant increase (up to 250%) in binding was observed on rat hepatocytes and on the human hepatoma cell line HepG2, while no changes in the number of cells or cell morphology could be observed. Scatchard plot analysis showed that IL-6 enhanced the number of TNF receptors without affecting the receptor affinity. The effect reached plateau levels after approximately 6 h and at IL-6 concentrations of 10 ng/ml. It could be completely eliminated by cotreatment of cells with anti-IL-6 antibodies, but not by treatment with anti-interferon-gamma (IFN-gamma), suggesting that IFN-gamma, which can enhance TNF receptor expression on a variety of cells, was not a mediator in this IL-6 effect. Treatment with inhibitors of protein or RNA synthesis completely abolished the IL-6-induced increase, suggesting that IL-6 caused an enhanced transcription of TNF receptor mRNA. IL-1 had no effect on TNF binding to HepG2. However, when cells were cotreated with IL-1 and IL-6, IL-1 could completely abrogate the IL-6 effect.
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PMID:Interleukin-6 enhances the expression of tumor necrosis factor receptors on hepatoma cells and hepatocytes. 165 25

Communication circuits operating between activated monocytes/macrophages and adjacent hepatocytes in the liver effect important alterations in hepatocyte function. We demonstrate here that primary human hepatocytes and hepatoma cells are able to function as effector cells in the recruitment of inflammatory cells in hepatic disease and inflammatory states by synthesizing a neutrophil/lymphocyte chemotactic factor, interleukin-8. We have further investigated the possibility that endogenous factors elaborated by activated peripheral blood monocytes and Kupffer cells in the liver are mediators of hepatocyte-derived interleukin-8 expression. Twenty-four-hour conditioned medium from lipopolysaccharide-stimulated peripheral blood monocytes and nonparenchymal human liver cells enriched for Kupffer cells induced a time-dependent increase in interleukin-8 messenger RNA levels in SK-hepatoma cells over a 24-hr period, similar to that seen for tumor necrosis factor-alpha or interleukin-1 beta induction of interleukin-8 in primary hepatocytes. Exogenously added lipopolysaccharide or recombinant interleukin-6 had no effect. Cell-associated interleukin-8 antigen was present in SK-hepatoma and primary hepatocytes that had been incubated with macrophage-conditioned medium, tumor necrosis factor or interleukin-1 beta. Similarly, neutrophil chemotactic activity was secreted by SK-hepatoma cells, a significant proportion of which could be blocked with interleukin-8--specific antiserum. Preincubation of macrophage-conditioned medium with neutralizing antibodies to tumor necrosis factor-alpha or interleukin-1 beta reduced its interleukin-8 messenger RNA-inducing capacity. Exposure of SK-hepatoma to conditioned medium followed by removal of the stimulus resulted in a rapid down-regulation of interleukin-8 messenger RNA to 50% of the maximum level within the first hour. These data suggest that products derived from activated Kupffer cells can modulate hepatoma cells and primary hepatocyte interleukin-8 gene expression. In addition, macrophage/monocyte-derived tumor necrosis factor-alpha and interleukin-1 beta have major roles in the positive regulatory component of this modulation.
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PMID:Kupffer cell-derived cytokines induce the synthesis of a leukocyte chemotactic peptide, interleukin-8, in human hepatoma and primary hepatocyte cultures. 166 18

Rat T-kininogen (T-KG), a cysteine protease inhibitor, is an acute phase reactant which is induced to high levels in response to inflammation. Both hormones and cytokines participate in this regulation. To investigate the cis-acting elements responsible for the induction of gene expression, various 5'-fragments of the rat T-KG gene were fused to a chloramphenicol acetyltransferase marker gene. These constructs were transfected into a rat hepatoma cell line which was then treated with tumor necrosis factor or interleukin-6 or both cytokines. Expression of the chloramphenicol acetyltransferase gene was induced with interleukin-6 treatment, but suppressed by tumor necrosis factor. The 5'-region of the T-KG gene responsible for conferring both of these effects was localized between nucleotides -404 to -210 upstream of the transcription start site. Fragments containing this region were found to be effective in either orientation, and could also regulate a heterologous promoter.
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PMID:Differential regulation of rat T-kininogen by tumor necrosis factor and interleukin-6. 170


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