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 triad of hemochromatosis, hepatoma and erythrocytosis is a rare combination. Hemochromatosis is often not recognized until the patient presents with the symptoms of hepatocellular carcinoma and erythrocytosis, and the development of erythrocytosis is an important clue to the under-lying hepatoma. The high serum iron concentration and the high saturation of the iron-binding protein, as well as the typical bone marrow hemosiderin pattern, are important aids in the recognition of hemochromatosis. To date, all patients with this triad have been elderly males. The clinical course is usually one of rapid deterioration and death. The seven previously reported cases have been reviewed and the relationship of the erythrocytosis to the increased production of erythropoietin is discussed.
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PMID:The triad of hemochromatosis, hepatoma and erythrocytosis. 21 27

A case of hepatocellular carcinoma associated with erythrocytosis is described. The patient was successfully treated with a combination chemotherapy of 5-fluorouracil, mitomycin C, cyclophosphamide and chromomycin A3, which was followed by a left lateral hepatectomy, and has survived for more than 9 years after the operation without any signs of recurrence. With the regression of hepatic tumor by the anticancer chemotherapy, the remission of erythrocytosis was observed, indicating that the tumor was producing erythropoietin. The data suggest also that erythrocytosis could be a marker for evaluation of chemotherapeutic effects in some patients with hepatocellular carcinoma.
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PMID:Hepatocellular carcinoma associated with erythrocytosis. A nine year survival after successful chemotherapy and left lateral hepatectomy. 22 17

The blood level of erythropoietin (Epo) is often anomalously low in anemic patients with inflammatory or malignant diseases. Therefore, we studied effects of pure recombinant immunomodulatory peptides on Epo formation in cultures of the human hepatoma cell line, HepG2. Interleukin (IL)-1 beta, IL-1 alpha, and tumor necrosis factor alpha lowered Epo production with half-maximal inhibition at 2, 5, and 20 U/ml, respectively. IL-6, transforming growth factor beta 2 and interferon gamma did not inhibit. Furthermore, IL-1 beta (10 U/ml) proved to block Epo formation in isolated serum-free perfused rat kidneys. Proposedly, monokines play a role in the pathogenesis of Epo deficiency in various diseases.
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PMID:Monokines inhibiting erythropoietin production in human hepatoma cultures and in isolated perfused rat kidneys. 131 Jan 33

This study reports the effects of cyclic adenosine 3'-5' monophosphate (cAMP) and hypoxia on erythropoietin biosynthesis in an erythropoietin-producing hepatocellular carcinoma cell line (Hep3B). Erythropoietin levels in the medium and cell extracts of low-density Hep3B cells after 20-hour incubation under hypoxic conditions (1% O2) were 25.33 +/- 1.50 mU/ml/10(7) cells and 3.60 +/- 0.50 mU/10(7) cells, respectively. These levels were significantly higher than in the respective normoxic controls (medium, 2.51 +/- 0.31 mU/ml/10(7) cells; cell extracts, undetectable [less than 0.31 mU/10(7) cells]). Cobalt also produced a significant increase in medium and cell erythropoietin levels. However, hypoxia and cobalt alone failed to produce an increase in cAMP accumulation in the cell cultures. Erythropoietin levels in the medium and cell extracts from cells exposed to 8-bromo cAMP (1 x 10(-4) mol/L) and forskolin (4 x 10(-6) mol/L) in a hypoxic atmosphere were significantly (p less than 0.05) higher than in the respective hypoxic controls. In addition, forskolin produced a significant (p less than 0.05) increase in cAMP accumulation (180 +/- 11.5 pmol/10(6) cells) under hypoxic conditions compared with the hypoxic controls (cAMP, 2.27 +/- 0.33 pmol/10(6) cells). These results suggest that cAMP elevation is not required in vitro in Hep3B cells for the increase in medium and cell levels of erythropoietin after hypoxia, but may be involved indirectly in erythropoietin biosynthesis, secretion, or both in vivo through some synergistic action with hypoxia.
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PMID:Characterization of erythropoietin production in a hepatocellular carcinoma cell line. 131 42

Using the human hepatoma cell line Hep G2, we have studied a possible role of protein kinase C (PKC) activity for regulation of erythropoietin (EPO) production. During a 72-h incubation, EPO production by the cells was stimulated sevenfold by exposure to low oxygen tension (1%) and threefold by exposure to cobaltous chloride (100 microM). The phorbol ester phorbol 12-myristate-13 acetate (PMA) led to a concentration-dependent inhibition of basal and stimulated EPO formation (ED50 10 nM). This decrease of EPO production, which was apparent already after 1 h of incubation with PMA, reached its maximal effect after 24 h and held on for 72 h. It was paralleled by an inhibition of the increase of EPO mRNA levels in response to stimulation. A 24-h preincubation of the cells with PMA (100 nM) virtually blunted the effect of hypoxia on EPO formation. Recovery of EPO synthesis after removal of PMA took 48-72 h. The effect of PMA on EPO production was mimicked by phorbol 12,13-dibutyrate (ED50 1 microM) but not by 4 alpha-phorbol 12,13-didecanoate. The synthetic diacylglycerol analogues oleolyl-acetylglycerol and dioctanoylglycerol (2-200 microM) also had no effect on either basal or stimulated EPO production. Treatment with PMA caused a translocation of the alpha-isoenzyme of PKC from the cytosol to the membrane after 1 h and a disappearance of the membrane-bound form after 24 h of incubation. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, two structurally different inhibitors of PKC activity, inhibited basal and stimulated EPO production with ED50 values of 9 nM and 50 microM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phorbol ester inhibits erythropoietin production in human hepatoma cells (Hep G2). 131 1

We examined the effects of insulin-like growth factors (IGFs) and insulin on erythropoietin (EPO) production by human hepatoma cells (Hep G2). Compared with normoxia (20% O2), EPO production by Hep G2 cells during a 72-h incubation was stimulated fivefold by exposure to low oxygen tension (1% O2) and nearly threefold by exposure to cobalt chloride (100 microM). IGF-I caused a concentration-dependent attenuation of EPO formation under normoxic conditions and inhibited (maximally 50%) EPO production stimulated by either low oxygen tension or cobalt [half-maximal effect (ED50) approximately 5 nM]. The increase of EPO mRNA levels in response to hypoxia was significantly reduced by IGF-I. Similarly to IGF-I, IGF-II (ED50 approximately 8 nM) and insulin (ED50 approximately 80 nM) also inhibited EPO formation in Hep G2 cells. IGF-I (100 pM-100 nM) stimulated the incorporation of radiolabeled alanine as a measure for total protein synthesis, 3H-labeled thymidine incorporation into DNA, and glycogen synthesis at 20 and 1% O2 in a concentration-dependent fashion. IGF-I exhibited a high affinity for the IGF-I receptor (apparent Kd approximately 3 nM). Unlabeled insulin was greater than 100-fold less potent than IGF-I in competing for 125I-IGF-I binding (apparent Kd approximately 360 nM). Conversely, insulin bound to the insulin receptor with high affinity (apparent Kd approximately 0.3 nM), whereas IGF-I was less than 1% as potent in competing for 125I-insulin binding. In summary, IGFs and insulin exert a negative control function on oxygen-regulated EPO production in Hep G2 cells. The inhibitory effect of IGFs and insulin on EPO formation appears to be mediated via the IGF-I receptor.
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PMID:Insulin-like growth factors decrease oxygen-regulated erythropoietin production by human hepatoma cells (Hep G2). 132 19

Cells derived from 9 human tumors were tested in vitro using 5 doses ranging from 1 to 5000 units of recombinant human erythropoietin (rhEpo) per ml to assess a proliferation response to this hormone. The following tumors were used: 2 melanomas, 1 hepatoma, 3 renal cell carcinomas, 1 adenocarcinoma of the lung, and 2 mammary carcinomas (with and without sex steroid hormone receptors). Compared to untreated cells, none of the cell lines exposed to rhEpo revealed differences in proliferation extending beyond the limits of methodological fluctuation. rhEpo thus does not have any effect on the growth of human tumors in vitro under the experimental conditions applied.
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PMID:Effect of recombinant human erythropoietin on the growth of human tumor cell lines in vitro. Micro-titertec-tetrazolium assay. 158 90

The mechanisms which control the production of erythropoietin (Epo) remain enigmatic. Recent data suggest that the half-time of Epo messenger RNA (mRNA) is increased by hypoxia in Hep 3B cells, a human hepatoma line. The post-transcriptional regulation of other rapidly degraded mRNAs is mediated by sequence-specific mRNA binding proteins. In order to determine if Epo mRNA specific binding proteins exist, we probed cytosolic lysates from Hep 3B cells and mouse tissues with radiolabeled Epo RNA. A cytosolic protein that binds specifically to Epo RNA was identified in the Epo-producing, hepatoblastoma Hep 3B cell line by gel mobility shift assay. This protein was identified in both normoxic and hypoxic cells and bound specifically to a 120-base fragment of the 3'-untranslated region (3'-UTR) of Epo mRNA. Binding was completed with unlabeled Epo RNA, but not with granulocyte-macrophage colony-stimulating factor RNA. Ultraviolet light cross-linked Epo RNA-protein complexes migrated as two bands of 70 and 135-140 kD on sodium dodecyl sulfate-polyacrylamide gels. Binding activity was markedly increased in brain and spleen lysates from mice subjected to 24 h of hypoxia. Therefore, the post-transcriptional regulation of Epo expression in response to hypoxia may in part be due to the interaction of Epo RNA with its specific binding protein.
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PMID:Hypoxia up-regulates the activity of a novel erythropoietin mRNA binding protein. 165 42

The present studies were undertaken to assess the direct effects of N6-cyclohexyladenosine (CHA), a stable adenosine analogue, on erythropoietin (Ep) secretion in hepatocellular carcinoma cells (Hep 3B). Ep levels in the medium of low density Hep 3B cells treated with CHA in concentrations of 10(-5) and 5 x 10(-5) M for 20 h under hypoxic conditions (1% O2) were significantly higher than that of hypoxic controls. In addition, CHA at the same concentrations produced significant increases in adenosine 3',5'-cyclic monophosphate (cAMP) levels in Hep 3B cells after 1-h incubation under hypoxic conditions when compared with hypoxic controls. Dibutyryl cAMP (10(-5), 10(-4) M) also caused significant increases in Ep secretion when compared with control hypoxic cells. On the other hand, 8-phenyltheophylline, an adenosine receptor antagonist, significantly inhibited the stimulatory effects of CHA on both Ep secretion and cAMP accumulation in the Hep 3B cell cultures in response to hypoxia. These data suggest that Ep secretion may be regulated by adenosine receptor-coupled activation of adenylyl cyclase and the generation of cAMP.
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PMID:Increased erythropoietin secretion in human hepatoma cells by N6-cyclohexyladenosine. 165 22

The role of protein kinase C (PKC) in the control of erythropoietin (Epo) production was studied using the human hepatoma cell line HepG2. Inhibition of PKC by staurosporine and the selective PKC inhibitor CGP 41251 significantly reduced Epo formation. No inhibition occurred with the inactive staurosporine derivative CGP 42700. Treatment with phorbol 12-myristate 13-acetate (PMA) for 24 h dose-dependently inhibited Epo formation, thus suggesting that down-regulation of PKC might be responsible for this inhibition. Immunoblotting experiments showed that incubation of HepG2 cells with PMA for 24 h resulted in a selective and almost complete down-regulation of PKC-alpha. Thus, PKC-alpha may play a permissive role in Epo synthesis in HepG2 cells.
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PMID:Inhibition of erythropoietin production by phorbol ester is associated with down-regulation of protein kinase C-alpha isoenzyme in hepatoma cells. 165 52


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