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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

In this study we have characterized the cell surface interleukin 1 (IL-1) receptor in HepG2 hepatoma cells. We found that HepG2 cells bind both IL-1 alpha and beta with high affinity, KDs of 136 and 180 pM and receptor densities of 16,000 and 8500 binding sites/cell respectively. The binding sites appeared to be predominantly type II since phorbol ester treatment of the cells, which selectively downregulates type II IL-1 receptors, reduced binding by 68% while treatment of the cells with an inhibitory monoclonal antibody specific for the type I receptor had no significant effect on IL-1 binding. Competition studies with a modified IL-1 beta analog (Glu4) also revealed binding kinetics more consistent with binding to type II receptors than to type I. Crosslinking and ligand blotting with human 125I-IL-1 demonstrated the presence of two bands, a 78 kDa band typical of crosslinking to type II (p60) receptor, and a 98 kDa band, typical of crosslinking to the type I (p80) receptor. Low level expression of the type I receptor was consistent with molecular biological studies employing polymerase chain reaction (PCR) amplification which indicated that mRNA for the type I receptor was produced by the HepG2 cells. Functional receptors were demonstrated by the induction of IL-8 by IL-1 stimulated cells.
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PMID:HepG2 cells predominantly express the type II interleukin 1 receptor (biochemical and molecular characterization of the IL-1 receptor). 131 62

The effect of conditioned medium on the biosynthesis and glycosylation profile of acute phase proteins secreted by the human hepatoma cell line Hep G2 was studied. Conditioned medium was prepared from nonactivated [CM-LPS(-)] and ex vivo lipopolysaccharide activated [CM-LPS(+)] monocytes from eight patients with active rheumatoid arthritis (RA), five patients with active systemic lupus erythematosus (SLE), and seven healthy subjects. The biosynthesis of albumin, alpha 1-antichymotrypsin and alpha 1-proteinase inhibitor and the profile of glycosylation of proteinase inhibitor were analysed. CM-LPS(-) from patients with SLE had a similar effect to CM-LPS(-) from healthy subjects. In contrast, CM-LPS(-) from patients with RA had the same effect as CM-LPS(+) from healthy donors. A similar effect to that of CM-LPS(+) of healthy subjects was seen with CM-LPS(+) from patients with SLE and with CM-LPS(+) from patients with RA. The treatment of CM-LPS(+) with antibodies against interleukin 6 neutralised most of its ability to induce changes in the biosynthesis and glycosylation of acute phase proteins. Antibodies to interleukin 1 and tumour necrosis factor alpha had only a limited effect on the ability of CM-LPS(+) to induce changes of albumin and alpha 1-antichymotrypsin syntheses, whereas they had no effect on the biosynthesis and glycosylation of proteinase inhibitor. These results indicate that: (a) monocytes isolated from patients with active SLE and active RA have different capabilities of inducing alterations of acute phase proteins in vitro; (b) ex vivo activation of monocytes from patients with SLE leads to the full induction of its capabilities to change acute phase proteins, whereas the activation of monocytes from patients with RA has no additive effects; and (c) interleukin 6 seems to be a major cytokine involved in the regulation of the glycosylation pattern of acute phase proteins.
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PMID:Different capabilities of monocytes from patients with systemic lupus erythematosus and rheumatoid arthritis to induce glycosylation alterations of acute phase proteins in vitro. 137 63

Acute inflammation is characterized by increased liver output of acute phase proteins (APP). Several cytokines including IL-6, leukemia inhibitory factor, and IL-11 are capable of stimulating APP synthesis by hepatocytes and hepatoma cells. We have tested the activity of a separate and unique cytokine oncostatin M (OM) and have found potent APP-inducing activity of human recombinant OM on hepatocytes. OM acted in a dose-dependent fashion (ED50 5 to 10 ng/ml) in stimulating APP synthesis in human HepG2 cells, rat H35 cells, and primary rat hepatocyte cultures, but not human Hep3B cells. Human OM induced equivalent to or greater responses than IL-6 in HepG2 cells, however, it was less effective than human IL-6 in stimulating rat cells. Northern analysis showed that OM stimulated mRNA levels of haptoglobin and alpha 1-antichymotrypsin in HepG2 cells. OM induced CAT activity in HepG2 cells transfected with CAT constructs containing IL-6-responsive elements, suggesting that OM induces transcription of native proteins through mechanisms involving IL-6-responsive element-like sequences in gene promoters. OM was also shown to act additively with IL-6 or leukemia inhibitory factor and synergistically with glucocorticoid or IL-1 in the induction of specific APP. These results suggest that OM plays a role as a mediator of APP synthesis in inflammatory responses.
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PMID:Recombinant oncostatin M stimulates the production of acute phase proteins in HepG2 cells and rat primary hepatocytes in vitro. 137 87

We have previously shown that induction of synthesis of the two major human acute phase proteins, serum amyloid A (SAA) and C-reactive protein (CRP), can be accomplished in the human hepatoma cell line Hep 3B, in the presence of dexamethasone, either by conditioned medium from LPS-stimulated monocytes or by the combination of IL-6 and IL-1. Neither of these cytokines alone caused significant induction of either SAA or CRP. In the present study we extended our earlier observations by evaluating the role of dexamethasone, the effect of different concentrations of IL-6 and IL-1 alpha in combination, and the possible role of TNF-alpha in regulating synthesis of SAA and CRP. Dexamethasone alone had no effect on induction of SAA or CRP. Incubation of Hep 3B cells with conditioned medium from LPS-stimulated monocytes, in the absence of dexamethasone, led to modest induction of SAA or CRP, but addition of dexamethasone potentiated this response in a dose-dependent manner. Similar results were obtained for the effect of dexamethasone on the induction of SAA by IL-6 plus IL-1 alpha. Checkerboard titration of IL-6 and IL-1 alpha revealed that increases in concentration of either cytokine led to dose-related increases in synthesis of both SAA and CRP as long as a minimal amount of the other cytokine was present. TNF-alpha alone had no significant effect on synthesis of either SAA or CRP, but the combination of IL-6 plus TNF-alpha led to substantial induction of SAA. This combination was less effective than the combination of IL-6 plus IL-1 alpha. No detectable effect of IL-6 plus TNF-alpha was observed on CRP synthesis. Both combinations of cytokines, IL-6 plus IL-1 alpha, and IL-6 plus TNF-alpha, caused increased SAA mRNA accumulation that roughly paralleled increase in synthesis. These data indicate that IL-6, IL-1 alpha, TNF-alpha, and dexamethasone in various combinations are all capable of influencing synthesis of SAA in Hep 3B cells, whereas only IL-6, IL-1 alpha, and dexamethasone can influence CRP synthesis.
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PMID:Effect of combinations of cytokines and hormones on synthesis of serum amyloid A and C-reactive protein in Hep 3B cells. 165 57

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

Ethanol alters many metabolic processes within the liver. Both ethanol abuse and the inability to mount an acute phase response (APR) have been associated with an increased morbidity and mortality in critically ill patients. To determine if ethanol influences the hepatic APR, relative amounts of two different human acute phase protein mRNA's were examined in the human hepatoma cell line Hep 3B before and after exposure to ethanol. Hep 3B cells were treated with one or more of the following: ethanol ((E) 150 mM); interleukin-1 beta ((IL-1) 200 units/ml); or interleukin-6 ((IL-6) 50 units/ml). After a 12-20 hr incubation relative amounts of mRNA for a1-protease inhibitor (PI) or beta fibrinogen were determined by Northern blot hybridization. Both ethanol and IL-6 were found to induce a1-PI mRNA. Fibrinogen mRNA was induced by IL-6 but not by ethanol, and no induction of PI or fibrinogen mRNA was found with IL-1. This suggests that under certain conditions, ethanol may influence acute phase protein metabolism. To our knowledge, this is the first description of an ethanol induced alteration of acute phase protein mRNA.
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PMID:Ethanol induces a1-protease inhibitor mRNA in Hep 3B cells. 165 92

1. Complex effects of principal inflammatory cytokines (IL-6, IL-1, TNF, IFN-gamma) on acute phase protein synthesis and other metabolic processes in cultured liver cells are briefly reviewed. 2. Molecular properties and biological functions of transforming growth factor-beta and epidermal growth factor are compared. 3. The effects of these factors with respect to both amino acid uptake and acute phase protein synthesis are described in detail. The results are found to be different for rat or mouse hepatocytes and human hepatoma cells.
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PMID:Epidermal growth factor and transforming growth factor-beta differently modulate the acute phase response elicited by interleukin-6 in cultured liver cells from man, rat and mouse. 169 99

We evaluated the effects of binary combinations of four cytokines on production of the positive acute phase proteins alpha-1 antichymotrypsin, haptoglobin and fibrinogen, and the negative acute phase proteins albumin and alpha-fetoprotein (AFP) in two human hepatoma cell lines. The effects of the cytokine combinations on the five proteins varied; each protein exhibited a unique and specific pattern of response to the cytokine combinations. In Hep G2 cells, antichymotrypsin was induced by all four cytokines, IL-6, IL-1, TNF-alpha, and transforming growth factor beta 1 alone, and their effects in binary combinations could be attributed to additive or minimally synergistic interactions. Fibrinogen was induced only by IL-6 and this induction was inhibited by IL-1 alpha, TNF-alpha or transforming growth factor beta 1. Haptoglobin was also induced only by IL-6, but TNF-alpha was the only cytokine that inhibited this induction at all concentrations of IL-6. Each of the four cytokines alone down regulated production of AFP and albumin. However, binary combinations of the four cytokines were simply additive, for the most part, in inhibiting AFP production, whereas the inhibitory effects of combinations of cytokines on albumin production differed significantly from simple additive effects. These observations, taken together with studies of effects of cytokine combinations on other acute phase proteins, indicate that the various acute phase proteins respond differently to different combinations of cytokines and that the potential exists for highly specific regulation of synthesis of individual plasma proteins by cytokine interactions. These findings imply that the acute phase response in vivo represents the integrated sum of multiple, separately regulated changes in gene expression.
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PMID:Effects of cytokine combinations on acute phase protein production in two human hepatoma cell lines. 170 30

The acute phase behaviour of the fast inhibitor of tissue-type plasminogen activator (PAI-1) in vivo has been attributed to increased synthesis by endothelial cells. However, most other acute phase proteins in vivo are synthesized in the liver, which process is regulated by cytokines and can be studied in the hepatoma derived cell line HepG2. In this study, we investigated whether the synthesis of PAI-1 by HepG2 cells is regulated by the cytokines recombinant IL-1, rIL-6 and rTNF. Recombinant IL-1 and rTNF each increased PAI-1 synthesis by HepG2 cells two to three fold, whereas rIL-6 hardly had an effect. Mixtures of rIL-1, rIL-6 and rTNF increased PAI-1 synthesis up to eleven fold. The effects observed were not due to non-specific effects on HepG2 cell metabolism, since synthesis of alpha-2-antiplasmin was not effected by any of those cytokines, whereas fibrinogen synthesis was increased three to four fold by rIL-6, but was unaffected by rIL-1. Thus, our results demonstrate that synthesis of PAI-1 by HepG2 cells is regulated by cytokines and implicate that the acute phase behaviour of PAI-1 in vivo at least in part may be due to an increased synthesis by the liver.
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PMID:PAI-1 synthesis in the human hepatoma cell line HepG2 is increased by cytokines--evidence that the liver contributes to acute phase behaviour of PAI-1. 171 Dec 45


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