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)

Low density lipoproteins (LDL) isolated from the plasma of patients with angiographically demonstrable coronary heart disease (CHD) induced accumulation of triglycerides, free cholesterol, and cholesteryl esters in cultured macrophages, smooth muscle cells, and endothelial cells derived from uninvolved intima of human aorta, but not in skin fibroblasts or hepatoma cells. The sialic acid content of LDL from CHD patients was 40-75% lower than that from healthy donors. There was a negative correlation between LDL sialic acid content and the LDL-induced accumulation of total intracellular cholesterol. Neuraminidase treatment of LDL from normal healthy donors produced sialic acid-depleted LDL (Ds-LDL) which was able to stimulate intracellular lipid accumulation. Neuraminidase treatment of LDL from CHD patients further increased its capacity to induce intracellular lipid accumulation. Sialic acid-poor LDL isolated by affinity chromatography of LDL from CHD patients induced a 2- to 4-fold increase of free and esterified cholesterol in human intimal smooth muscle cells. Binding, uptake, and degradation of 125I-labeled Ds-LDL by macrophages and endothelial cells were 1.5- to 2-fold higher than for native LDL. Binding and uptake of Ds-LDL was inhibited 64-93% by the addition of 20-fold excess acetylated LDL (Ac-LDL); in the inverse experiment, the level of inhibition was 35-54%. These data indicate that a sialic acid-poor form of LDL isolated from CHD patients can interact with both native and scavenger LDL receptors. A sialic acid-poor form of LDL may be a naturally occurring ligand that interacts with the scavenger receptor(s) on macrophages and endothelial cells.
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PMID:Sialic acid content of human low density lipoproteins affects their interaction with cell receptors and intracellular lipid accumulation. 151 8

This paper reviews epidemiological investigations which have identified an inverse relationship between alcohol consumption and death from coronary heart disease: evidence from studies of mixed populations as well as of single-sex populations have, on the whole, demonstrated that this relationship is independent of sex or age. This 'cardioprotective effect' of alcohol can be explained, at least in part, by ethanol-related increases in high density lipoprotein cholesterol and reduced platelet coagulability. With certain beverages, especially red wine, phenolic compounds may provide additional protection by altering eicosanoid metabolism in favour of increased prostacyclin and decreased thromboxane synthesis, as well as antioxidant functions which prevent the peroxidation of low-density lipoprotein. Trans-resveratrol, a tri-hydroxy stilbene present in the skins of specific grape cultivars, is a constituent of certain red wines which may play a crucial role in modulating lipoprotein metabolism, eicosanoid synthesis, oxidation and coagulation. Preliminary studies using the human hepatoma cell line HepG2 are described, demonstrating that this compound has no effect upon cell viability or overall protein synthesis in these cells, and at high concentrations DNA synthesis as measured by radioactive thymidine incorporation is enhanced. Reduced intracellular concentration and secretion of apolipoprotein B have been shown to occur in response to resveratrol although a clear dose-dependency has not yet been demonstrated. The mechanisms underlying these changes as well as the effects upon the synthesis and secretion of other apolipoproteins are under active investigation in our laboratory.
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PMID:Beyond alcohol: beverage consumption and cardiovascular mortality. 766 73

Apolipoprotein (apo) A-I is the major protein component of high-density lipoproteins (HDLs), which are responsible for reverse cholesterol transport from peripheral tissues to the liver. A low level of plasma HDL is correlated with susceptibility to atherosclerosis and coronary heart disease. Mammalian apo A-I synthesis has been attributed mainly to liver and intestine. Recently, apo A-I expression has been shown in porcine brain capillaries, suggesting an independent lipid metabolism within the brain. In this study, protein synthesis and secretion were investigated in primary cultures of porcine brain microvascular endothelial cells and compared with those in large vessel endothelium. Active protein synthesis in vitro was demonstrated by metabolic labeling. Cerebral endothelial cells were shown to secrete apo A-I into the culture supernatant, whereas aortic endothelial cells were negative for apo A-I expression. Further studies of transcriptional regulation showed that cerebral endothelium was responsive to apo A-I-inducing agents, such as cholesterol, insulin, and retinoic acid, as previously shown in human hepatoma HepG2 cells. Thus, cultures of porcine cerebral endothelial cells may represent a suitable model for physiological studies of apo A-I-regulation with regard to brain lipid metabolism and blood-brain barrier function. To investigate the interspecies conservation of regulatory elements, 178 bp of the 5' flanking region of the porcine apo A-I gene was cloned using PCR techniques. Alignments of the cDNA, of the deduced apo A-I protein sequence, and of the 5' promoter region with the corresponding genomic sequences of different species show a high degree of similarity between the porcine and the primate apo A-I genes, thus indicating a similar function and possibly common regulatory mechanisms in those species. In contrast, the rodent and avian apolipoprotein A-I promoter sequences differed significantly.
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PMID:Expression of apolipoprotein A-I in porcine brain endothelium in vitro. 829 40

Tamoxifen is the endocrine treatment of choice for all women with hormonally responsive breast cancer. 30 years of experience in both the laboratory and clinical setting have shown tamoxifen to be an effective adjuvant treatment with minor short term adverse effects. However, as therapeutic use has extended to 5 years and beyond, and as clinical trials begin which will assess the effectiveness of tamoxifen as a preventive treatment, concern about possible long term adverse effects is justified. Tamoxifen has an estrogen-like influence on the skeletal and cardiovascular systems, resulting in decreases in both postmenopausal bone loss and low density lipoprotein (LDL) levels. These effects will, it is hoped, result in decreases in the incidences of osteoporosis and coronary heart disease, which are major causes of morbidity and mortality in the postmenopausal age group. Tamoxifen therapy also results in decreased rates of contralateral breast cancer. Long term tamoxifen treatment may result in a small increase in the incidence of endometrial and/or hepatocellular carcinoma, but with millions of women taking tamoxifen for long periods, such small increases in incidence translate to a significant number of women at risk. Tamoxifen is clearly beneficial for short term treatment, but the clinical decision of tamoxifen use in the long term must be made on the individual benefits versus risks of tamoxifen treatment.
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PMID:A risk-benefit assessment of tamoxifen therapy. 850 18

High serum lipoprotein(a) (Lp(a)) is a risk factor for vascular disorders. Our preliminary observations suggest that, in some patients with coronary heart disease with high serum Lp(a) levels, administration of aspirin reduced Lp(a) levels. Therefore, we aimed to analyze the effects of aspirin on the production of apo(a), the expression of apolipoprotein(a) (apo(a)) mRNA and the transcriptional activity of apo(a) gene promoter. Aspirin (5 mM) reduced the apo(a) levels in culture medium of human hepatocytes and suppressed apo(a) mRNA expression to 73% and 85% of the controls, respectively. Aspirin also reduced the transcriptional activity of apo(a) gene transfected into HepG2 hepatoma cells in a dose-dependent manner, with a maximal effect at 5 mM (44.3 +/- 1.5% of the control). Sodium salicylate (5 mM) also reduced apo(a) gene transcription, whereas indomethacin (10 microM) had no effect. Deletion analysis of apo(a) gene promoter showed that promoter region extending from -30 to +138 is critical for the effect of aspirin. Furthermore, enhanced production, mRNA expression, and gene transcription of apo(a) by interleukin-6 were also inhibited by aspirin. These results demonstrate that aspirin reduces apo(a) production from hepatocytes via reduction of the transcriptional activity of apo(a) gene with suppression of apo(a) mRNA expression. The suppression of apo(a) production by aspirin may at least in part play a role in the anti-atherogenic effect of aspirin in vascular disorders.
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PMID:Aspirin reduces apolipoprotein(a) (apo(a)) production in human hepatocytes by suppression of apo(a) gene transcription. 1056 80

Statins are inhibitors of the rate-limiting enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. In addition to reducing LDL cholesterol, statin treatment increases the levels of the antiatherogenic HDL and its major apolipoprotein apoA-I. Here, we investigated the molecular mechanisms of apoA-I regulation by statins. Treatment with statins increased apoA-I mRNA levels in human HepG2 hepatoma cells, and this effect was reversed by the addition of mevalonate, implicating HMG-CoA reductase as the relevant target of these drugs. Pretreatment with Actinomycin D abolished the increase of apoA-I mRNA, indicating that statins act at the transcriptional level. Indeed, statins increased the human apoA-I promoter activity in transfected cells, and we have identified a statin response element that coincides with a PPARalpha response element known to confer fibrate responsiveness to this gene. The statin effect could be abolished not only by mevalonate, but also by geranylgeranyl pyrophosphate, whereas inhibition of geranylgeranyl transferase activity or treatment with an inhibitor of the Rho GTP-binding protein family increased PPARalpha activity. Using dominant negative forms of these proteins, we found that Rho A itself mediates this response. Because cotreatment with statins and fibrates activated PPARalpha in a synergistic manner, these observations provide a molecular basis for combination treatment with statins and fibrates in coronary heart disease.
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PMID:Statin-induced inhibition of the Rho-signaling pathway activates PPARalpha and induces HDL apoA-I. 1139 Apr 24

Prostanoids have been implicated in the transcriptional control of several genes. Since prostanoid synthesis inhibitors are commonly used in subjects with coronary heart disease we studied the effect of cyclooxygenase (COX) inhibition on apolipoprotein AI (apoAI) expression in a human hepatoma cell line (HepG2) transfected with full-length apoAI promoter attached to the chloramphenicol acetyl transferase (CAT) reporter gene. To control for transfection efficiency, the cells were cotransfected with the plasmid pCMV.SPORT-beta-gal containing the beta-galactosidase gene driven by the cytomegalovirus promoter. Treatment of these cells with varying concentrations of indomethacin (INDO, 0, 50, 100, and 300 micromol/L) resulted in a dose-dependent decrease in apoAI promoter activity (% acetylation corrected for beta-galactosidase activity: were 46.1 +/- 2.6, 29.9 +/- 1.2, 25.2 +/- 2.9, and 17.2 +/- 2.8, respectively, P <.001). INDO treatment did not cause significant changes in beta-galactosidase activity. A similar reduction in apoAI promoter activity was found after treating the cells with 50 micromol/L acetylsalicylic acid (ASA) (31.8 +/- 1.8%, P <.001), suggesting that the effect of INDO is related to COX inhibition rather than a peculiar effect of INDO. Nuclear run-off assays indicated that treatment of cells with 50 micromol/L INDO resulted in 31.4% reduction in apo A1 transcription rate (P <.0002). Northern blot analysis of RNA from HepG2 cells treated with 50 micromol/L of INDO for 72 hours showed that the apoAI mRNA concentration relative to G3PDH mRNA was 4,043.0 +/- 84.6 and 3,064.0 +/- 49.8 in control and INDO-treated cells, respectively (P <.0006). Kinetic studies of apoAI mRNA in HepG2 cells indicated that the half-life of apoAI mRNA was not significantly altered with 50 micromol/L INDO treatment. Apo AI mRNA half-life was 25.3 hours in control cells and 26.9 hours in INDO-treated cells. Western blot analysis of culture media of HepG2 cells treated with 50 micromol/L of INDO for 72 hours showed a significant reduction in apoAI protein (6,760.0 +/- 318.1 v 4,773.0 +/- 112.0 arbitrary units, P <.004). Treatment of cells with either arachidonic acid (COX substrate) or various prostanoids including prostaglandin I(2), thromboxane B(2), (+/-)5-HETE, or (+/-)12-HETE did not significantly alter apoAI promoter activity. However, prostaglandin E(1) and E(2) at the highest concentration tested (50 nmol/L) significantly repressed apoAI promoter activity. COX activity measurements in HepG2 cells verified the efficacy of COX inhibition by INDO. It is concluded that COX inhibition with INDO or ASA downregulates apoAI expression at the transcriptional level. This effect could not be attributed to either arachidonic acid excess or to a deficiency in various prostanoids tested.
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PMID:Cyclooxygenase inhibition is associated with downregulation of apolipoprotein AI promoter activity in cultured hepatoma cell line HepG2. 1476 68

We studied acception of cholesterol from Fu5AH hepatoma cells by blood serum from subjects with normal level of high-density lipoprotein cholesterol and hyperlipidemia (alone or in combination with other risk factors for coronary heart disease). Cholesterol-binding activity of high-density lipoproteins decreased in subjects with hyperlipidemia alone or in combination with excess body weight and/or arterial hypertension. Impairment of high-density lipoprotein activity was associated with changes in their phospholipid composition.
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PMID:Impaired antiatherogenic function of high-density lipoproteins in the presence of various risk factors for coronary heart disease. 1602 33

This review covers the diagnosis and outcomes of histological subphenotypes of nonalcoholic fatty liver disease (NAFLD) including nonalcoholic steatohepatitis (NASH) in both children and adults. Serious outcomes of NAFLD include cirrhosis, hepatocellular carcinoma, coronary heart disease, and diabetes. The ability to determine differential outcomes by NAFLD subtypes is dependent upon both the adequate assessment of histological subtypes, as well as the appropriate measure of the outcome of interest. Steatohepatitis, which can only be diagnosed by liver biopsy, has a greater risk for both hepatic and systemic complications than simple steatosis. Differences in subphenotypes between children and adults and among children have only recently been described. Careful future attention should be given to determine their influence on clinical outcomes. Enhanced understanding of the epidemiology of NAFLD subphenotypes may help organize collaborative efforts between hepatologists, pathologists, cardiologists, endocrinologists, and primary care physicians to develop clinical management protocols.
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PMID:Hepatic, cardiovascular, and endocrine outcomes of the histological subphenotypes of nonalcoholic fatty liver disease. 1895 94

In the recent decade the subject of general hepatology has undergone significant upgrading. Several breakthrough discoveries have lead to substantial improvement in the antiviral treatment of viral hepatitis, the therapy of hepatocellular carcinoma and the development of noninvasive diagnosis of the severity of liver disease. Nonalcoholic fatty liver disease (NAFLD] is now established as one of the most common causes of chronic liver disease in the Western world. NAFLD can progress to cirrhosis and its associated complications. This issue of "Harefuah" is dedicated to the current knowledge and challenges in liver disease and transplantation and to novel discoveries in this field. Two new important guidelines of the Israeli Association for the Study of the Liver are published in this issue, the first deals with the management of ascites and its complications and the second relates to the innovative antiviral treatment of chronic hepatitis C virus infection. An extensive review on this latter subject is also included, summarizing the major breakthroughs in this field: the development of the new direct acting antiviraL agents and the role of IL28B polymorphism in the response to treatment. One article argues the concept of the high hepatitis B virus (HBV) vertical transmission in an Arab cohort in Israel, while another paper provides data on a significantly improved response rate to antiviral therapy in HIV-HCV co-infected patients. Increased serum level of lipoprotein-associated phospholipase A2 level, an independent predictor of coronary heart disease, was detected in patients with nonalcohoLic fatty liver disease [NAFLD] in another article. The issue also provides encouraging data showing that following two decades of liver transplantation in Israel, the survival rate has improved. Several additional articles in the issue shed further light on recent discoveries in the field of hepatology.
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PMID:[Challenges in liver diseases and transplantation]. 2333 Feb 53


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