scholarly journals Eicosapentaenoic acid inhibits cell growth and triacylglycerol secretion in McA-RH7777 rat hepatoma cultures

1992 ◽  
Vol 286 (1) ◽  
pp. 305-312 ◽  
Author(s):  
J C Fox ◽  
R V Hay

The plasma triacylglycerol-decreasing effect of fish-oil fatty acids was studied in vitro by using the rapidly growing cultured rat hepatoma cell line McA-RH7777. Cells were exposed to albumin-complexed eicosapentaenoic acid (C20:5n-3; EPA), to oleic acid (C18:1n-9; OA), or to albumin alone. Cell growth was similar in albumin- and OA-supplemented cultures, but EPA treatment inhibited growth. As estimated by [14C]glycerol incorporation, OA stimulated both net triacylglycerol synthesis and secretion over control levels in a dose-dependent manner. EPA stimulated triacylglycerol synthesis in similar fashion to OA, but paradoxically decreased net triacylglycerol secretion and led to exaggerated intracellular accumulation of radiolabelled triacylglycerol. The EPA and OA effects were additive at low concentrations of total fatty acid, but at higher fatty acid concentrations OA appeared to negate some effects of EPA. Chemical analysis of albumin- and OA-treated cultures revealed OA-dominant profiles for both cellular and medium triacylglycerol-associated fatty acids. In contrast, EPA was the principal fatty acid in cellular triacylglycerol of EPA-supplemented cultures, whereas medium triacylglycerol from these cultures contained very little EPA. We conclude that McA-RH7777 hepatoma cells readily synthesize EPA-containing triacylglycerol molecules, but they have variable capacity for secreting them. We consider potential mechanisms to account for the effects of EPA in this system.

2006 ◽  
Vol 84 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Monica P Polo ◽  
Margarita G de Bravo

Monoterpenes have multiple pharmacological effects on the metabolism of mevalonate. Geraniol, a dietary monoterpene, has in vitro and in vivo anti-tumor activity against several cell lines. We have studied the effects of geraniol on growth, fatty-acid metabolism, and mevalonate metabolism in the human hepatocarcinoma cell line Hep G2. Up to 100 µmol geraniol/L inhibited the growth rate and 3-hydroxymethylglutaryl coenzyme A reductase (HMG-CoA) reductase activity of these cells. At the same concentrations, it increased the incorporation of cholesterol from the medium in a dose-dependent manner. Geraniol-treated cells incorporated less 14C-acetate into nonsaponifiable lipids, inhibiting its incorporation into cholesterol but not into squalene and lanosterol. This is indicative of an inhibition in cholesterol synthesis at a step between lanosterol and cholesterol, a fact confirmed when cells were incubated with 3H-mevalonate. The incorporation of 3H-mevalonate into protein was also inhibited, whereas its incorporation into fatty acid increased. An inhibition of Δ5 desaturase activity was demonstrated by the inhibition of the conversion of 14C-dihomo-γ-linolenic acid into arachidonic acid. Geraniol has multiple effects on mevalonate and lipid metabolism in Hep G2 cells, affecting cell proliferation. Although mevalonate depletion is not responsible for cellular growth, it affects cholesterogenesis, protein prenylation, and fatty-acid metabolism.Key words: geraniol, Hep G2, HMG-CoA reductase, mevalonate, fatty acids.


2006 ◽  
Vol 231 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Eun-Sun Hwang ◽  
Hyong Joo Lee

Lycopene, which is the predominant carotenoid in tomatoes and tomato-based foods, may protect humans against various cancers. Effects of lycopene on the adhesion, invasion, migration, and growth of the SK-Hep1 human hepatoma cell line were investigated. Lycopene inhibited cell growth in dose-dependent manners, with growth inhibition rates of 5% and 40% at 0.1 μM and 50 μM lycopene, respectively, after 24 hrs of incubation. Similarly, after 48 hrs of incubation, lycopene at 5 μM and 10 μM decreased the cell numbers by 30% and 40%, respectively. Lycopene decreased the gelatinolytic activities of both matrix metalloproteinase (MMP)-2 and MMP-9, which were secreted from the SK-Hep1 cells. Incubation of SK-Hep1 cells with 110 μM of lycopene for 60 mins significantly inhibited cell adhesion to the Matrigel-coated substrate in a concentration-dependent manner. To study invasion, SK-Hep1 cells were grown either on Matrigel-coated Transwell membranes or in 24-well plates. The cells were treated sequentially for 24 hrs with lycopene before the start of the invasion assays. Cell growth and death were assessed under the same conditions. The invasion of SK-Hep1 cells treated with lycopene was significantly reduced to 28.3% and 61.9% of the control levels at 5 μM and 10 μM lycopene, respectively (P < 0.05). In the migration assay, lycopene-treated cells showed lower levels of migration than untreated cells. These results demonstrate the antimetastatic properties of lycopene in inhibiting the adhesion, invasion, and migration of SK-Hep1 human hepatoma cells.


1993 ◽  
Vol 293 (1) ◽  
pp. 173-179 ◽  
Author(s):  
C Espinet ◽  
A M Vargas ◽  
M R el-Maghrabi ◽  
A J Lange ◽  
S J Pilkis

The hormonal regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene expression was studied in the rat hepatoma cell line FAO-1. Both 6-phosphofructo-2-kinase and fructose-2,6-bisphosphatase activities were detected in FAO-1 cells, at 68% of the levels found in rat liver. Northern blot analysis showed that FAO-1 cells, like rat liver, contained a predominant species of bifunctional enzyme mRNA, which is 2.2 kb in size. A sensitive RNAase protection assay revealed the presence in FAO-1 cells of an additional mRNA species, which is generated when transcription is initiated from the skeletal muscle promoter of the rat liver/skeletal muscle gene. The liver/skeletal muscle mRNA ratio in FAO-1 cells was 10:1, which is similar to that observed in rat liver. In contrast, in another rat hepatoma cell line, FTO-2B, only the skeletal muscle mRNA was detected. Insulin and dexamethasone induced the liver bifunctional enzyme mRNA in FAO-1 cells by 2-4-fold and 10-20-fold respectively in a concentration- and time-dependent manner, and their effects were antagonized by cyclic AMP. Transcription of the gene in FAO-1 cells, measured by nuclear run-on assays, was also enhanced by dexamethasone and insulin. It is concluded that the FAO-1 cell line is similar to liver with respect to both the preferential use of the liver promoter of the gene and its regulation by hormones, and is therefore an excellent model for the study of the hepatic expression of this gene.


1999 ◽  
Vol 341 (2) ◽  
pp. 453-460 ◽  
Author(s):  
Richard J. PEASE ◽  
David WIGGINS ◽  
E. David SAGGERSON ◽  
Jeni TREE ◽  
Geoffrey F. GIBBONS

Clones of HepG2 cells were selected that stably express the cDNA for hormone-sensitive lipase (HSL). When cells were cultured in the presence of labelled extracellular oleate, accumulation of labelled fatty acid as cellular triacylglycerol (TAG) was significantly lower in the transfectants compared with the wild-type cells. There was no change in the net rate of phospholipid (PL) synthesis. Culture of cells containing isotopically prelabelled TAG resulted in a greater net loss of TAG from the transfected cells than from the wild-type cells. The excess loss of labelled TAG was primarily due to an increased TAG fatty acid oxidation. Free fatty acid release into the medium was not increased in the transfectants, nor was the very low rate of lipoprotein lipid secretion. Also, there was no increased net trafficking of fatty acids from TAG into PLs. Changes in the 3H:14C ratio of TAG prelabelled with [3H]glycerol and [14C]oleate suggested that none of excess TAG fatty acid released in the transfected cells underwent intracellular re-esterification to TAG prior to oxidation. The results suggest that fatty acids mobilized by HSL are directed immediately into the oxidative pathway and are not available for biosynthetic processes. It appears likely, therefore, that intracellular TAG-derived fatty acids which enter the oxidative pathway exist in a different compartment from those that are directed towards synthesis.


2014 ◽  
Vol 92 (5) ◽  
pp. 363-368 ◽  
Author(s):  
Wei Zhu ◽  
Yingzhi Liu ◽  
Konghe Hu ◽  
Wenxue Li ◽  
Jianling Chen ◽  
...  

This study sought to understand the effects of vitronectin (VTN) on the growth of SMMC-7721 hepatoma cells. In addition, this study examined how VTN inhibits the induction of apoptosis in SMMC-7721 cells by 3,3′-diindolylmethane (DIM), a metabolite of natural phytochemicals, and preliminarily investigated the signaling molecules involved in this process. A cell proliferation reagent was used to observe the effects of VTN on cell proliferation rates. Laser scanning confocal microscopy was performed to observe the effects of VTN on the morphology of tubulin, a component of the cytoskeleton. Flow cytometry and Western blotting assays were used to observe the inhibitory effects of VTN on DIM-induced apoptosis in SMMC-7721 cells and changes in the expression levels of the signaling molecules involved in this process. VTN promoted tumor cell growth in a concentration-dependent manner and inhibited apoptosis caused by the effects of apoptosis-inducing agents. Under in vitro experimental conditions, VTN contributed to the growth of SMMC-7721 hepatoma cells and protected them from the effects of an apoptosis-inducing agent. These findings suggest that during hepatocellular carcinogenesis, VTN may promote tumor cell growth and inhibit chemically induced apoptosis.


1999 ◽  
Vol 343 (1) ◽  
pp. 191-197 ◽  
Author(s):  
Rolf K. BERGE ◽  
Lise MADSEN ◽  
Hege VAAGENES ◽  
Karl Johan TRONSTAD ◽  
Martin GÖTTLICHER ◽  
...  

Hypolipidaemic fatty acid derivatives and polyunsaturated fatty acids decrease concentrations of plasma triacylglycerol by mechanisms that are not fully understood. Because poor susceptibility to β- and/or ω-oxidation is apparently a determinant of the peroxisome proliferating and hypolipidaemic capacity of fatty acids and derivatives, the relative importance of activation of the peroxisome-proliferator-activated receptor α (PPARα), fatty acid oxidation and triacylglycerol synthesis were examined. We have compared the effects of differentially β-oxidizable fatty acids on these parameters in primary cultures of rat hepatocytes. Tetradecylthioacetic acid (TTA), 2-methyleicosapentaenoic acid and 3-thia-octadecatetraenoic acid, which are non-β-oxidizable fatty acid derivatives, were potent activators of a glucocorticoid receptor (GR)-PPARα chimaera. This activation was paradoxically reflected in an substantially increased oxidation of [1-14C]palmitic acid and/or oleic acid. The incorporation of [1-14C]palmitic acid and/or oleic acid into cell-associated and secreted triacylglycerol was decreased by 15-20% and 30% respectively with these non-β-oxidizable fatty acid derivatives. The CoA ester of TTA inhibited the esterification of 1,2-diacylglycerol in rat liver microsomes. Both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) activated GR-PPARα. EPA increased the oxidation of [1-14C]palmitic acid but DHA had no effect. The CoA ester of EPA inhibited the esterification of 1,2-diacylglycerol, whereas DHA-CoA had no effect. The ratio between synthesized triacylglycerol and diacylglycerol was lower in hepatocytes cultured with EPA in the medium compared with DHA or oleic acid, indicating a decreased conversion of diacylglycerol to triacylglycerol. Indeed, the incorporation of [1-14C]oleic acid into secreted triacylglycerol was decreased by 20% in the presence of EPA. In conclusion, a decreased availability of fatty acids for triacylglycerol synthesis by increased mitochondrial β-oxidation and decreased triacylglycerol formation caused by inhibition of diacylglycerol acyltransferase might explain the hypolipidaemic effect of TTA and EPA.


2014 ◽  
Vol 25 (3-4) ◽  
pp. 24-33
Author(s):  
O. I. Dzjuba ◽  
M. V. Yatsenko

The article deals with the history of the study and the current state of research of physiological and biochemical properties of the plant genus Sedum that are useful for human and has been used in folk medicine for many years. It was noticed that antioxidant properties of extracts from plants S. sarmentosum, S. sempervivoides, S. takesimense were caused by the presence of phenolic compounds. Methanol extract of plants S. takesimense exhibited strong scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals as well as significant inhibitory effects on lipid peroxidation and low density lipoprotein (LDL) oxidation induced by a metal ion Cu2+. Various immunomodulatory activities of various fractions of plants extracts (S. dendroideum, S. kamtschaticum, S. sarmentosum, S. telephium) are observed. It was shown that the ethanol extract of S. sarmentosum and it’s fractions suppressed specific antibody and cellular responses to ovalbumin in mice. The methanol extract of plants S. sarmentosum reduced the levels of anti-inflammatory markers, such as volume of exudates, number of polymorphonuclear leukocytes, suppressed nitric oxide synthesis in activated macrophages via suppressed induction of inducible nitric oxide synthase (iNOS). Polysaccharides fractions from plants S. telephium inducing productions of tumor necrosis factor alpha (TNF-α), increasing the intensity of phagocytosis in vitro and in vivo. Methanol extract from the whole part of S. kamtschaticum strongly inhibit PGE2 production from lipopolysaccharide-induced RAW 264.7 cells, a mouse macrophage cell line via modulating activity in gene expression of the enzyme cyclooxygenase-2 (COX-2). The methanol extract of plants S. sarmentosum and the major kaempferol glycosides from S. dendroideum have antinociceptive activity. It was noticed that anti-adipogenic activity of extracts from plants S. kamtschaticum were caused by inhibition of peroxisome-proliferator-activated receptor γ (PPARγ) expression and it’s dependent target genes, such as genes encoding adipocyte protein 2 (аР2), lipoprotein lipase (LPL), adiponectin and CD36. Polysaccharides fractions from S. telephium cause inhibition of cell adhesion of human fibroblast (MRC5) to laminin and fibronectin via interfere with integrin-mediated cell behaviour and they contributed to the role of polysaccharides in cell-matrix interaction. The methanol extract of plants S. sarmentosum exhibited a significant inhibitory activity in the chick embryo chorioallantoic membrane angiogenesis in a dose-dependent manner. The crude alkaloid fraction of S. sarmentosum caused a dose-dependent inhibition of cell proliferation on murine hepatoma cell line BNL CL.2 and human hepatoma cell line HepG2 without necrosis or apoptosis. Alkaloids from plants S. sarmentosum may improve survival of hepatoma patients via the inhibition of excessive growth of tumor cells. Plant’s juices have antiviral activity (S. sarmentosum, S. spurium, S. stahlii). Crude ethanol extract S. praealtum have spermicidal activity of the in mice and a relevant inhibitory effect of aqueous extract on human spermatozoa motility as well as an anti-fertilizing activity in rats. Hepatoprotective triterpenes, e.g., δ-amyrone, 3-epi-δ-amyrin, δ-amyrin and sarmentolin were isolated from S. sarmentosum. 2- and 2,6-substituted piperidine alkaloids (e.g., norsedamine, allosedridine, sedamine, allosedamine) are observed in plants S. acre, which in the presence of data on the use of pyridine and piperidine derivatives for treating neurodegenerative diseases (e.g., Alzheimer's disease), points on the promising research in this area. Taking into account that biologically active compounds are accumulated in the aboveground vegetative organs of plants of Sedum, the prospects of further study of the use of Sedum for the purposes of biotechnology and in the pharmaceutical industry becomes apparent. This work extends the existing views regarding the use of plants Sedum.


2020 ◽  
Vol 22 (1) ◽  
pp. 202
Author(s):  
Josephin Glück ◽  
Julia Waizenegger ◽  
Albert Braeuning ◽  
Stefanie Hessel-Pras

Pyrrolizidine alkaloids (PAs) are a group of secondary metabolites produced in various plant species as a defense mechanism against herbivores. PAs consist of a necine base, which is esterified with one or two necine acids. Humans are exposed to PAs by consumption of contaminated food. PA intoxication in humans causes acute and chronic hepatotoxicity. It is considered that enzymatic PA toxification in hepatocytes is structure-dependent. In this study, we aimed to elucidate the induction of PA-induced cell death associated with apoptosis activation. Therefore, 22 structurally different PAs were analyzed concerning the disturbance of cell viability in the metabolically competent human hepatoma cell line HepaRG. The chosen PAs represent the main necine base structures and the different esterification types. Open-chained and cyclic heliotridine- and retronecine-type diesters induced strong cytotoxic effects, while treatment of HepaRG with monoesters did not affect cell viability. For more detailed investigation of apoptosis induction, comprising caspase activation and gene expression analysis, 14 PA representatives were selected. The proapoptotic effects were in line with the potency observed in cell viability studies. In vitro data point towards a strong structure–activity relationship whose effectiveness needs to be investigated in vivo and can then be the basis for a structure-associated risk assessment.


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