linoleic-acid and Liver-Neoplasms

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are functionally the most important omega-3 polyunsaturated fatty acids (PUFAs). Oral supply of these fatty acids increases their levels in plasma and cell membranes, often at the expense of the omega-6 PUFAs arachidonic acid (ARA) and linoleic acid. This results in an altered pattern of lipid mediator production to one which is less pro-inflammatory. We investigated whether short term intravenous supply of omega-3 PUFAs could change the levels of EPA, DHA, ARA and linoleic acid in plasma and erythrocytes in patients with hepatic colorectal metastases.. Twenty patients were randomised to receive a 72 hour infusion of total parenteral nutrition with (treatment group) or without (control group) omega-3 PUFAs. EPA, DHA, ARA and linoleic acid were measured in plasma phosphatidylcholine (PC) and erythrocytes at several times points up to the end of infusion and 5 to 12 days (mean 9 days) after stopping the infusion.. The treatment group showed increases in plasma PC EPA and DHA and erythrocyte EPA and decreases in plasma PC and erythrocyte linoleic acid, with effects most evident late in the infusion period. Plasma PC and erythrocyte EPA and linoleic acid all returned to baseline levels after the 5-12 day washout. Plasma PC DHA remained elevated above baseline after washout.. Intravenous supply of omega-3 PUFAs results in a rapid increase of EPA and DHA in plasma PC and of EPA in erythrocytes. These findings suggest that infusion of omega-3 PUFAs could be used to induce a rapid effect especially in targeting inflammation.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Arachidonic Acid; Child; Colorectal Neoplasms; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Female; Humans; Inflammation; Linoleic Acid; Liver Neoplasms; Male; Middle Aged

Linoleic acid (LA) has been shown to cause inflammation and promote development of colorectal cancer (CRC). Moreover, many literatures show that LA is associated with cancer metastasis. Metastatic cancer cells have high stemness, suggesting that LA might affect the stemness of cancer cells. In this study, we examined the effect of LA on the hedgehog system, which affects cancer stemness. In CT26 cells, LA treatment induced the expression of sonic hedgehog

Topics: Animals; Colorectal Neoplasms; Hedgehog Proteins; Humans; Kruppel-Like Transcription Factors; Linoleic Acid; Liver Neoplasms; Mice; Nuclear Proteins; Transcription Factors; Zinc Finger Protein Gli2

Altered metabolites are important for the tumourigenicity of hepatocellular carcinoma (HCC). We performed integrative metabolomics analysis of the metabolites changes in portal venous blood and in comparison with the metabolites changes in liver tissues and stool samples of HCC patients and healthy liver donors.. Serum (portal and central vein), liver tissue (HCC tumour and adjacent non-tumour, normal liver) and stool samples were collected from 102 subjects (52 HCC patients and 50 healthy controls) in the discovery cohort; and 100 subjects (50 HCC patients and 50 healthy controls) in an independent validation cohort. Untargeted metabolomic profiling was performed using high-performance liquid chromatography-mass spectrometry. The function of candidate metabolites was validated in hepatocyte cell lines.. Detailed metabolomic evaluation showed distinct clusters of metabolites in serum, liver tissue and stool samples from patients with HCC and control individuals (p<0.001). HCC patients had significantly higher levels of portal vein serum and HCC tissue metabolites of DL-3-phenyllactic acid, L-tryptophan, glycocholic acid and 1-methylnicotinamide than healthy controls, which were associated with impaired liver function and poor survival. On the other hand, HCC patients had lower levels of linoleic acid and phenol in portal vein and stool samples than healthy controls. Linoleic acid and phenol significantly inhibited HCC proliferation, inferring their anti-HCC function as protective metabolites.. The integrative metabolome analysis of serum, tissue and stool metabolites revealed unreported metabolic alterations in HCC patients. In portal vein, we identified elevated and depleted metabolites signifying that they might play a role in HCC development.

Topics: Carcinoma, Hepatocellular; Humans; Linoleic Acid; Liver Neoplasms; Metabolome; Metabolomics; Phenols; Portal Vein

Cancer dormancy is a state characterized by the quiescence of disseminated cancer cells, and tumor recurrence occurs when such cells re-proliferate after a long incubation period. These cancer cells tend to be treatment resistant and one of the barriers to successful therapeutic intervention. We have previously reported that long-term treatment of cancer cells with linoleic acid (LA) induces a dormancy-like phenotype. However, the mechanism underpinning this effect has not yet been clarified. Here, we investigate the mechanism of LA-induced quiescence in cancer cells. We first confirmed that long-term treatment of the mouse colorectal cancer cell line CT26 with LA induced quiescence. When these cells were inoculated subcutaneously into a syngeneic mouse and fed with an LA diet, the inoculated cancer cells maintained the quiescent state and exhibited markers of dormancy. LA-treated CT26 cells showed reduced oxidative phosphorylation, glycolysis, and energy production as well as reduced expression of the regulatory factors

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Glycolysis; Humans; Linoleic Acid; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; MicroRNAs; Mitochondria; Neoplasm Recurrence, Local; Oxidative Stress; Transcriptome; Up-Regulation

Topics: Actins; Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Collagen; Disease Models, Animal; Drug Compounding; Drug Delivery Systems; Endopeptidases; Fibroblasts; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Linoleic Acid; Liver Neoplasms; Membrane Proteins; Mice; Mice, Inbred C57BL; Mycophenolic Acid; Nanoparticles; NIH 3T3 Cells; Polymers; Xenograft Model Antitumor Assays

There is currently no effective treatment for advanced hepatocellular carcinoma (HCC), and chemotherapy has little effect on long-term survival of HCC patients, largely due to the cancer stem cell (CSC) chemoresistance of HCC.. We constructed a small-molecule nanometer-sized prodrug (nanoprodrug) loaded with salinomycin (SAL) for the treatment of HCC. SAL was encapsulated by the prodrug LA-SN38 (linoleic acid modified 7-ethyl-10-hydroxycamptothecin) to construct a self-assembled nanoprodrug further PEGylated with DSPE-PEG. Delivery of the SAL- and LA-SN38-based nanoprodrugs effectively promoted apoptosis of HCC cells, exerted inhibition of HCC tumor-sphere formation as well as HCC cell motility and invasion, and reduced the proportion of CD133+ HCC-CSC cells. In nude mice, the nanoprodrug suppressed growth of tumor xenografts derived from human cell lines and patient.. Our results show that SAL-based nanoprodrugs are a promising platform for treating patients with HCC and a novel strategy for combination therapy of cancers.

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Humans; Irinotecan; Linoleic Acid; Liver Neoplasms; Male; Mice, Inbred BALB C; Mice, Nude; Nanoparticles; Neoplastic Stem Cells; Phosphatidylethanolamines; Polyethylene Glycols; Prodrugs; Pyrans; Xenograft Model Antitumor Assays

Hepatocellular carcinoma (HCC) is a common cause of cancer-related death worldwide. As obesity and diabetes become more prevalent, the contribution of non-alcoholic fatty liver disease (NAFLD) to HCC is rising. Recently, we reported intrahepatic CD4

Topics: 3T3 Cells; Animals; Apoptosis; Carcinogenesis; Carcinoma, Hepatocellular; Carnitine O-Palmitoyltransferase; CD4-Positive T-Lymphocytes; Enzyme Inhibitors; Humans; Linoleic Acid; Liver Neoplasms; Mice; Mice, Inbred C57BL; Mitochondria; Models, Biological; Non-alcoholic Fatty Liver Disease; Perhexiline; PPAR alpha; Reactive Oxygen Species; Up-Regulation

Nonalcoholic fatty liver is characterized by the abnormal accumulation of triglycerides within hepatocytes, resulting in a steatotic liver. Glucagon-like peptide 1 and its analog exendin-4 can ameliorate certain aspects of this syndrome by inducing weight loss and reducing hepatic triglyceride accumulation, but it is unclear whether these effects result from the effects of glucagon-like peptide 1 on the pancreas, or from direct action on the liver. This study investigated the direct action and putative cellular mechanism of exendin-4 on steatotic hepatocytes in culture. Steatosis was induced in cultured HepG2 human hepatoma cells by incubation in media supplemented with 2 mM each of linoleic acid and oleic acid. Steatotic hepatocytes were then pre-incubated in the protein kinase A inhibitor H89 for 30 min, then treated with exendin-4 over a period of 24 h. Cell viability and triglyceride content were characterized by a TUNEL assay and AdipoRed staining, respectively. Our results showed that steatotic cells maintained high levels of intracellular triglycerides (80%) compared to lean controls (25%). Exendin-4 treatment caused a significant reduction in intracellular triglyceride content after 12 h that persisted through 24 h, while protein kinase A inhibitors abolished the effects of exendin-4. The results demonstrate the exendin-4 induces a partial reduction in triglycerides in steatotic hepatocytes within 12 h via the GLP-1 receptor-mediated activation of protein kinase A. Thus, the reduction in hepatocyte triglyceride accumulation is likely driven primarily by downregulation of lipogenesis and upregulation of β-oxidation of free fatty acids.

Topics: Carcinoma, Hepatocellular; Cell Survival; Cyclic AMP-Dependent Protein Kinases; Exenatide; Fatty Liver; Glucagon-Like Peptide 1; Hep G2 Cells; Hepatocytes; Humans; Isoquinolines; Linoleic Acid; Lipogenesis; Liver Neoplasms; Oleic Acid; Pancreas; Peptides; Sulfonamides; Triglycerides; Venoms

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death. Non-alcoholic fatty liver disease (NAFLD) affects a large proportion of the US population and is considered to be a metabolic predisposition to liver cancer. However, the role of adaptive immune responses in NAFLD-promoted HCC is largely unknown. Here we show, in mouse models and human samples, that dysregulation of lipid metabolism in NAFLD causes a selective loss of intrahepatic CD4(+) but not CD8(+) T lymphocytes, leading to accelerated hepatocarcinogenesis. We also demonstrate that CD4(+) T lymphocytes have greater mitochondrial mass than CD8(+) T lymphocytes and generate higher levels of mitochondrially derived reactive oxygen species (ROS). Disruption of mitochondrial function by linoleic acid, a fatty acid accumulated in NAFLD, causes more oxidative damage than other free fatty acids such as palmitic acid, and mediates selective loss of intrahepatic CD4(+) T lymphocytes. In vivo blockade of ROS reversed NAFLD-induced hepatic CD4(+) T lymphocyte decrease and delayed NAFLD-promoted HCC. Our results provide an unexpected link between lipid dysregulation and impaired anti-tumour surveillance.

Topics: Animals; Carcinogenesis; Carcinoma, Hepatocellular; Case-Control Studies; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Choline; Diet; Disease Models, Animal; Genes, myc; Hepatocytes; Humans; Linoleic Acid; Lipid Metabolism; Liver; Liver Neoplasms; Male; Methionine; Mice; Mice, Inbred C57BL; Mitochondria; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Reactive Oxygen Species

A series of linoleic acid-modified glycol chitosan (LAGC) conjugates were synthesized and characterized by FTIR and (1)H NMR. The effect of the amount of linoleic acid (LA) on the physicochemical properties of LAGC conjugates was investigated. The mean diameters of three LAGC nanoparticles determined by dynamic light scattering ranged from 204 to 289 nm. The critical aggregation concentration values of LAGC conjugates in aqueous solution were 0.0148, 0.0348, and 0.0807 mg/ml, respectively. Paclitaxel (PTX) was physically loaded into the LAGC nanoparticles by a dialysis method. The drug loading content and encapsulation efficiency of PTX-loaded LAGC (PTX-LAGC) nanoparticles increased with an increasing ratio of the hydrophobic LA to hydrophilic glycol chitosan in the conjugates. PTX-LAGC nanoparticles were almost spherical in shape observed by transmission electron microscopy. In vitro release revealed that PTX release from the nanoparticles was reduced as the LA substitution degree of LAGC conjugates increased. Compared with the commercial formulation Taxol, PTX-LAGC-1 nanoparticles exhibited comparable cellular uptake and cytotoxicity against HepG2 cells in vitro. Importantly, PTX-LAGC-1 nanoparticles demonstrated the stronger antitumor efficacy against hepatic H22 tumor-bearing mice than Taxol (p < 0.05). Therefore, glycolipid-like LAGC nanoparticles had a potential as delivery vehicles for tumor therapy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Line, Tumor; Chitosan; Drug Carriers; Humans; Hydrophobic and Hydrophilic Interactions; Linoleic Acid; Liver Neoplasms; Male; Mice; Nanoparticles; Neoplasm Transplantation; Paclitaxel; Particle Size

To explore the potential of iodized linoleic acid (ILA) and its 5-fluoro-deoxyuridine ester (IFU) to inhibit hepatocellular carcinoma (HCC) cells in vitro and tumors in vivo.. ILA and its constituent component IFU were chemically synthesized, purified, and confirmed by 1H-NMR. The HCC cell lines, QGY-7703 (5-fluorouracil (5-FU) treatment sensitive) and SMMC-7721 (5-FU resistant), were treated with ILA, IFU, 5-FU, or traditional lipiodol for 72 hours. Survival rates of the treated cells were assessed by the methyl thiazolyl tetrazolium method, and used to calculate the IC50 and IC90. In addition, thirty nude mice were subcutaneously inoculated with SMMC-7721 cells and randomly divided two weeks later into four treatment groups (n = 6 each) for intra-tumoral injection of ILA, IFU, 5-FU, lipiodol or DMSO (controls). The rate of tumor inhibition (RTI) was calculated for each group at week 4 after treatment.. For the cultured SMMC-7721 cells, the inhibitory concentrations for ILA, IFU, and 5-FU were: IC50: 134.38 mumol/L, 17.55 mumol/L, and 7.38 mumol/L; IC90: 192.88 mumol/L, 97.63 mumol/L, and more than 200 mumol/L. For the cultured QGY-7703 cells, the inhibitory concentrations for ILA, IFU, and 5-FU were: IC50: 109.55 mumol/L, 44.79 mumol/L, and 98.06 mumol/L; IC90: all, more than 200 mumol/L. In both cell types, the IC50 of lipiodol was more than 400 mumol/L. Compared with the RTI of the control mice (100%), the RTI of ILA-treated mice was 31.9% (t = 2.37, P less than 0.05), of IFU-treated mice was 56.9% (t = 4.91, P less than 0.01), and of 5-FU-treated mice was 31.0% (t = 2.59, P less than 0.05). The RTI of IFU was significantly stronger than that of either ILA or 5-FU (P less than 0.05). The lipiodol treatment showed no inhibition effect on tumors (P more than 0.05).. ILA and IFU can effectively inhibit the growth of HCC cells in vitro and tumors in vivo. Furthermore, IFU outperforms ILA in inhibiting HCC growth.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Fluorouracil; Humans; Inhibitory Concentration 50; Linoleic Acid; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Xenograft Model Antitumor Assays

The preparation and characterization of a novel escheriosomal nanoparticle formulation of a potent anticancer conjugate, 2,6-diisopropylphenol-linoleic acid (2,6P-LA), and evaluation of its anticancer efficacy against diethyl nitrosamine-induced hepatocellular carcinoma (HCC) in BALB/c mice.. Escheriosomized 2,6P-LA nanoparticles were characterized for size, zeta-potential, entrapment efficiency, release kinetics and in vivo toxicity. Their anticancer potential was evaluated on the basis of survival, DNA fragmentation, caspase-3 activation, western blot analysis of apoptotic factors and histopathological changes in hepatocytes of treated animals.. The escheriosomized 2,6P-LA nanoparticles exhibited low toxicity, biocompatibility and bioavailability. As revealed by apoptosis induction, survival rate, expression profiles of Bax, Bcl-2 and caspase-9, escheriosomized 2,6P-LA nanoparticles were more effective in the treatment of HCC than the free form of 2,6P-LA in experimental animals.. 2,6P-LA-bearing escheriosome nanoparticles are effective in suppressing HCC in mice. Original submitted 17 January 2012; Revised submitted 27 August 2012; Published online 14 January 2013.

Topics: Animals; Apoptosis; Carcinoma, Hepatocellular; Caspase 3; DNA Fragmentation; Humans; Linoleic Acid; Liver Neoplasms; Mice; Nanoparticles; Propofol; Survival Analysis

To determine the antioxidant activity and cytotoxicity of Phyllanthus virgatus crude extract compared to Phyllanthus amarus.. Phenolic contents of the hydromethanolic extracts were measured using Folin-Ciocalteu reagent. Antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl hydrate free radical scavenging and antilipid peroxidation assays. Cytotoxicity on human hepatoma HepG2 cells was assessed by trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability assays. A stereomicroscope was used to observe and photograph the morphology of the cells. Oxygen consumption of the HepG2 cells was measured using a Clark oxygen electrode.. The extract of P. virgatus, which contained more phenolic compounds than P. amarus extract, had higher cytotoxicity and showed higher free radical scavenging activity and more inhibition of peroxidation in a linoleic acid system. P. virgatus extract conspicuously increased the oxygen consumption of HepG2 cells, while P. amarus extract had little stimulatory effect.. The hydromethanolic extract of P. virgatus had stronger antioxidant and cytotoxic action than P. amarus extract. The stimulation of HepG2 cell respiration by P. virgatus extract suggests the extract alters mitochondrial function; this action could play a role in the cytotoxicity of this plant.

Topics: Antioxidants; Cytotoxins; Free Radicals; Hep G2 Cells; Humans; Linoleic Acid; Lipid Peroxidation; Liver Neoplasms; Mitochondria; Oxygen Consumption; Phyllanthus; Phytotherapy; Plant Extracts; Plant Preparations

Activation of the activator protein 1 (AP-1) transcription factor as well as increased serum levels of vascular endothelial growth factor (VEGF) and interleukin (IL)-8 predict poor prognosis of patients with hepatocellular carcinomas (HCCs). Moreover, HCC patients display reduced selenium levels, which may cause lipid peroxidation and oxidative stress because selenium is an essential component of antioxidative glutathione peroxidases (GPx). We hypothesized that selenium-lipid peroxide antagonism controls the above prognostic markers and tumor growth. (1) In human HCC cell lines (HCC-1.2, HCC-3, and SNU398) linoleic acid peroxide (LOOH) and other prooxidants enhanced the expression of VEGF and IL-8. LOOH up-regulated AP-1 activation. Selenium inhibited these effects. This inhibition was mediated by glutathione peroxidase 4 (GPx4), which preferentially degrades lipid peroxides. Selenium enhanced GPx4 expression and total GPx activity, while knock-down of GPx4 by small interfering RNA (siRNA) increased VEGF, and IL-8 expression. (2) These results were confirmed in a rat hepatocarcinogenesis model. Selenium treatment during tumor promotion increased hepatic GPx4 expression and reduced the expression of VEGF and of the AP-1 component c-fos as well as nodule growth. (3) In HCC patients, increased levels of LOOH-related antibodies (LOOH-Ab) were found, suggesting enhanced LOOH formation. LOOH-Ab correlated with serum VEGF and IL-8 and with AP-1 activation in HCC tissue. In contrast, selenium inversely correlated with VEGF, IL-8, and HCC size (the latter only for tumors smaller than 3 cm).. Reduced selenium levels result in accumulation of lipid peroxides. This leads to enhanced AP-1 activation and consequently to elevated expression of VEGF and IL-8, which accelerate the growth of HCC. Selenium supplementation could be considered for investigation as a strategy for chemoprevention or additional therapy of early HCC in patients with low selenium levels.

Topics: Adult; Animals; Carcinoma, Hepatocellular; Case-Control Studies; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Diethylnitrosamine; Disease Models, Animal; Glutathione Peroxidase; Hepatocytes; Humans; Interleukin-8; Linoleic Acid; Lipid Peroxides; Liver Neoplasms; Phospholipid Hydroperoxide Glutathione Peroxidase; Rats; Rats, Inbred F344; Selenium; Transcription Factor AP-1; Vascular Endothelial Growth Factor A

The aim of the present work was to evaluate the influence of cyclosporine (CsA) and sirolimus (SRL) on fatty acid (FA) desaturase activities. These enzymes (named Delta9, Delta6, and Delta5 desaturases) catalyze reactions leading to the biosynthesis of n-9, n-6, and n-3 FA families. n-3 FA family, derived from alpha-linolenic acid, is involved in the prevention of vascular events, which appear after successful kidney transplantation. Five groups of HepG(2) cells in culture were treated with either CsA (1 microg/microL and 2 microg/microL) or SRL (10 ng/mL and 20 ng/mL) for 3 days, including a control group without immunosuppressive treatment. We studied the incorporation and metabolic conversion of radioactive [1-(14)C]palmitic, linoleic, and eicosatrienoic acids. We also analyzed fatty acid composition. The distribution of radioactive metabolic products after incubation of these cells with [1-(14)C]palmitic acid revealed a decrease in Delta9 desaturase activity in the presence of each immunosuppressive drug: CsA = 0.61 +/- 0.01; SRL = 0.59 +/- 0.04 versus control = 0.79 +/- 0.05 (P < .01). We observed a significant increase in Delta6 and Delta5 desaturase activities under the influence of the immunosuppressive drugs: radiolabeled linoleic acid (CsA: 0.93 +/- 0.04; SRL: 1.02 +/- 0.03 vs control 0.60 +/- 0.03; P < .01) and eicosatrienoic acid (CsA: 1.12 +/- 0.02; SRL: 1.07 +/- 0.01 vs control 0.75 +/- 0.01; P < .01). In conclusion, CsA and SRL modulated the biosynthesis of polyunsaturated FAs, decreasing Delta9 desaturase and increasing Delta6 and Delta5 desaturase activities.

Topics: Arachidonic Acids; Carcinoma, Hepatocellular; Cell Line, Tumor; Cyclosporine; Fatty Acid Desaturases; Fatty Acids; Humans; Immunosuppressive Agents; Kinetics; Linoleic Acid; Liver Neoplasms; Palmitic Acid; Sirolimus

Conjugated linoleic acid (CLA), found in dairy products, in beef and lamb has been demonstrated to possess anticancer properties protecting several tissues from developing cancer. Moreover, it has been shown to modulate apoptosis in several cancer cell lines. The aim of this study was to investigate which signaling transduction pathways were modulated in CLA-induced apoptosis in human hepatoma SK-HEP-1 cells. The cells exposed to CLA were evaluated for PPARalpha, PP2A, pro-apoptotic proteins Bak, Bad and caspases, and anti-apoptotic proteins Bcl-2 and Bcl-X(L). Cells were also treated with okadaic acid, a PP2A inhibitor, or with Wy-14643, a specific PPARalpha agonist. The CLA-induced apoptosis was concomitant to the increase of percentage of cells in the S phase, PPARalpha, PP2A and pro-apoptotic proteins; simultaneously, antiapoptotic proteins decreased. Inhibition of PP2A prevented apoptosis, and PPARalpha agonist showed similar effect as CLA. The increased PP2A could be responsible for the dephosphorylation of Bcl-2 and Bad, permitting apoptotic activity of Bax and Bad. The increase of caspase 8 and 9 suggested that both the intrinsic and extrinsic apoptotic pathways were induced. PP2A was probably increased by PPARalpha, since putative PPRE sequences were found in genes encoding its subunits. In conclusion, CLA induces apoptosis in human hepatoma SK-HEP-1 cells, by increasing PPARalpha, PP2A and pro-apoptotic proteins.

Topics: Antineoplastic Agents; Apoptosis; Base Sequence; bcl-2 Homologous Antagonist-Killer Protein; bcl-Associated Death Protein; bcl-X Protein; Blotting, Western; Carcinoma, Hepatocellular; Caspases; Cell Line, Tumor; Cell Survival; DNA, Neoplasm; Humans; Linoleic Acid; Liver Neoplasms; Molecular Sequence Data; Okadaic Acid; PPAR alpha; Protein Phosphatase 2; Proto-Oncogene Proteins c-bcl-2; Pyrimidines; Signal Transduction

Although hepatitis C and B viruses and alcohol consumption are the major risk factors for hepatocellular carcinoma (HCC), dietary habits may also be relevant. A hospital-based case-control study was conducted in Italy in 1999-2002, including 185 HCC cases and 412 cancer-free controls. Dietary habits were assessed using a validated food-frequency questionnaire to compute nutrient intakes. Odds ratios (OR) and corresponding confidence intervals (CI) were calculated using the energy-adjusted residual models. Inverse association emerged for linoleic acid (OR=0.35 for highest versus lowest tertile; 95% CI: 0.18-0.69) and, possibly, beta-carotene (OR=0.48; 95% CI: 0.24-0.93). Among minerals, iron intake was associated with increased HCC risk (OR=3.00; 95% CI: 1.25-7.23), but the association was considerably reduced when iron from wine was excluded (OR=1.61; 95% CI: 0.78-3.30). In conclusion, a diet rich in linoleic acid containing foods (e.g. white meats and fish) and beta-carotene was inversely related to HCC risk.

Topics: Adult; Aged; Aged, 80 and over; Alcohol Drinking; beta Carotene; Carcinoma, Hepatocellular; Case-Control Studies; Diet; Diet Surveys; Female; Humans; Italy; Linoleic Acid; Liver Neoplasms; Male; Middle Aged; Risk Factors; Surveys and Questionnaires

In rats, oxidized fats activate the peroxisome proliferator-activated receptor alpha (PPARalpha), leading to reduced triglyceride concentrations in liver, plasma and very low density lipoproteins. Oxidation products of linoleic acid constitute an important portion of oxidized dietary fats. This study was conducted to check whether the primary lipid peroxidation product of linoleic acid, 13-hydroperoxy-9,11-octadecadienoic acid (13-HPODE), might be involved in the PPARalpha-activating effect of oxidized fats. Therefore, we examined the effect of 13-HPODE on the expression of PPARalpha target genes in the rat Fao and the human HepG2 hepatoma cell lines. In Fao cells, 13-HPODE increased the mRNA concentration of the PPARalpha target genes acyl-CoA oxidase (ACO), cytochrome P450 4A1 and carnitine-palmitoyltransferase 1A (CPT1A). Furthermore, the concentration of cellular and secreted triglycerides was reduced in Fao cells treated with 13-HPODE. Because PPARalpha mRNA was not influenced, we conclude that these effects are due to an activation of PPARalpha by 13-HPODE. In contrast, HepG2 cells seemed to be resistant to PPARalpha activation by 13-HPODE because no remarkable induction of the PPARalpha target genes ACO, CPT1A, mitochondrial HMG-CoA synthase and delta9-desaturase was observed. Consequently, cellular and secreted triglyceride levels were not changed after incubation of HepG2 cells with 13-HPODE. In conclusion, this study shows that 13-HPODE activates PPARalpha in rat Fao but not in human HepG2 hepatoma cells.

Topics: Acyl-CoA Oxidase; Animals; Carcinoma, Hepatocellular; Carnitine O-Palmitoyltransferase; Cell Line, Tumor; Cytochrome P-450 CYP4A; Gene Expression; Humans; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Lipid Peroxides; Lipids; Liver; Liver Neoplasms; Liver Neoplasms, Experimental; PPAR alpha; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Triglycerides

Hoki (Johnius belengerii) skin gelatin was hydrolyzed with three commercial enzymes to identify radical-scavenging potencies of derived peptides. Peptides derived from tryptic hydrolysate exhibited the highest scavenging activities on superoxide, carbon-centered 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assessed by ESR spectroscopy. Following consecutive chromatographic separations of tryptic hydroolysate, the peptide sequence His-Gly-Pro-Leu-Gly-Pro-Leu (797 Da) acted as a strong radical scavenger under studied conditions. Further, this peptide could act as an antioxidant against linoleic acid peroxidation and the activity was closer to the highly active synthetic antioxidant butylated hydroxytoluene (BHT). In addition, antioxidative enzyme levels in cultured human hepatoma cells were increased in the presence of this peptide and it was presumed to be the peptide involved in maintaining the redox balance in the cell environment. Present data indicate that free-radical-scavenging activities of hoki skin gelatin peptides substantially contribute to their antioxidant properties measured in different oxidative systems.

Topics: Amino Acid Sequence; Animals; Antioxidants; Carcinoma, Hepatocellular; Fishes; Free Radical Scavengers; Gelatin; Humans; Hydrolysis; Linoleic Acid; Liver Neoplasms; Oxidation-Reduction; Peptides; Skin; Tumor Cells, Cultured

This study was conducted to determine the secretion rate and composition of lipoproteins secreted by HepG2 cells as influenced by the type of fatty acid present in the incubation medium. Cells were preincubated for 24 h with palmitic, oleic, elaidic, linoleic or conjugated linoleic acid (CLA), and the lipoproteins secreted during a subsequent incubation period of 24 h were collected for analysis. The secretion rate of apolipoprotein B-100 (apoB) was significantly greater in HepG2 cells preincubated with elaidic acid compared with those preincubated with palmitic or oleic acid; apoB secretion was greater in cells preincubated with CLA compared with those preincubated with linoleic acid. The lipid composition of secreted lipoproteins was also influenced by fatty acid treatment, resulting in significantly smaller lipoprotein particles secreted by cells preincubated with elaidic acid and CLA compared with those secreted by cells treated with oleic acid and linoleic acid, respectively. Our results are relevant to human metabolism for the following reasons: (1) the size of plasma low-density lipoproteins (LDLs) is determined, at least in part, by the composition of apoB-containing lipoproteins secreted by the liver; (2) small plasma LDL particles are associated with an increased risk of coronary heart disease; and (3) specific dietary fatty acids can affect the composition and size of plasma LDLs, thereby imparting a relative atherogenicity to plasma LDLs independent of LDL cholesterol concentration. The present study therefore suggests that elaidic acid and CLA promote the hepatic secretion of small apoB-containing lipoproteins, which could lead to an increased production of small plasma LDL particles.

Topics: Apolipoprotein B-100; Apolipoproteins B; Carcinoma, Hepatocellular; Humans; Linoleic Acid; Linoleic Acids, Conjugated; Lipids; Lipoproteins; Liver; Liver Neoplasms; Oleic Acid; Oleic Acids; Particle Size; Trans Fatty Acids; Tumor Cells, Cultured

Recently, there has been a great interest in the effects of different types of n-6 polyunsaturated acids (n-6 PUFAs) upon the immune system and cancer development. However, the effects of n-6 PUFAs are still controversial and as yet undefined. The present study aimed to investigate the anti-tumor effects of n-6 PUFAs against EL4 thymoma and the associated immune mechanisms. To this, sesame oil, a vegetable oil enriched with n-6 PUFAs, or free linoleic acid (LA) were administered intraperitoneally into C57BL/6 mice before and after challenge with EL4 lymphoma cells. Treatment with either sesame oil or LA attenuated the growth and metastasis of EL4 lymphoma. The anti-tumor effect of LA was superior to that of sesame oil, and associated with an increase in the survival rate of the tumor-bearing mice. In addition, both sesame oil and LA showed dose-dependent anti-lymphoma growth in vitro. Treatment with LA generated significant increases in the anti-lymphoma cytolytic and cytostatic activities of T cells and macrophages, respectively, and enhanced production of IL-2 and IFN-gamma while decreased production of IL-4, IL-6 and IL-10. In summation, the results suggest that n-6 PUFAs, represented by LA, can attenuate EL4 lymphoma growth and metastasis through enhancing the specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines. These findings might be of great importance for a proper design of systemic nourishment with PUFAs emulsions for cancer patients.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cytokines; Enzyme-Linked Immunosorbent Assay; Fatty Acids, Unsaturated; Female; Linoleic Acid; Liver Neoplasms; Macrophages; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Sesame Oil; Spleen; Stimulation, Chemical; T-Lymphocytes, Cytotoxic; Th1 Cells; Thymoma; Thymus Neoplasms

Liver carnitine palmitoyl transferase (L-CPT) I is a key regulatory enzyme of long-chain fatty acid (LCFA) oxidation that ensures the first step of LCFA import into the mitochondrial matrix. In rat hepatocytes, we showed previously that L-CPT I gene expression was induced by LCFAs as well as by fibrates. The aim of this study was to determine whether LCFA-induced L-CPT I gene expression was mediated by PPARalpha. For this purpose, we constructed a PPARalpha-dominant negative receptor to inhibit endogenous PPARalpha signaling. Highly conserved hydrophobic and charged residues (Leu459 and Glu462) in helix 12 of the ligand-binding domain were mutated to alanine. These mutations led to a total loss of transcriptional activity due to impaired coactivator recruitment. Furthermore, competition studies confirmed that the mutated PPARalpha receptor abolished the wild-type PPARalpha receptor action and thus acted as a powerful dominant negative receptor. When overexpressed in rat hepatoma cells (H4IIE) using a recombinant adenovirus, the mutated PPARalpha receptor antagonized the clofibrate-induced L-CPT I gene expression, whereas it did not affect LCFA-induced L-CPT I. These results provide the first direct demonstration that LCFAs regulate L-CPT I transcription through a PPARalpha-independent pathway, at least in hepatoma cells.

Topics: Adenoviridae; Animals; Carcinoma, Hepatocellular; Carnitine O-Palmitoyltransferase; Cell Line, Tumor; Chlorocebus aethiops; Clofibrate; COS Cells; Gene Expression Regulation, Enzymologic; Hypolipidemic Agents; Linoleic Acid; Liver Neoplasms; PPAR alpha; Rats; Recombinant Proteins; Transcriptional Activation

We investigated the effects of different fatty acids (FAs) or with different degrees of unsaturation on cytochrome P450 2E1 (CYP2E1) induction and protein kinase C (PKC) activity in human hepatoma HepG2 cells. As the degree of unsaturation increased, the cell survival rate decreased for FAs with 18 carbons, but linolenic acid (LNA) or docosahexaenoic acid (DHA) groups were similar even through they have different degrees of unsaturation. Treatment with palmitic acid (PA), oleic acid (OA), linoleic acid (LA), LNA, and DHA resulted in respective cellular FA concentrations of C16:0 (43.1%), C18:1 (18.5%), C18:2 (7.4%), LNA (2.85%), and C22:6 (3.13%), which was highest for the FA that was used as the treatment, indicating that their incorporation within the cell is directly proportional to treatment. After 2 hours of cultivation, the lipid peroxide (LPO) in the DHA group increased 600% compared with control, and was much higher than in the groups treated with the other FAs, with LNA > LA > OA > PA. CYP2E1 induction increased with greater effect as the degree of unsaturation of OA, LA, and DHA increased. PA did not affect PKC activity, but DHA treatment increased PKC activity the most. The effects of LNA and LA were similar, but less than that of DHA, and that of OA was lower still, indicating that activity of PKC is proportional to the degree of unsaturation, and not the configuration of the FA. Increased plasma membrane concentrations of n-3 FA, such as DHA, might exert regulatory effects on PKC by increasing membrane fluidity, causing changes in CYP2E1, elevating levels of LPO, or producing oxidative stress.

Topics: Carcinoma, Hepatocellular; Cell Membrane; Cytochrome P-450 CYP2E1; Dietary Fats, Unsaturated; Docosahexaenoic Acids; Enzyme Induction; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Humans; Linoleic Acid; Lipid Peroxides; Liver; Liver Neoplasms; Membrane Fluidity; Oleic Acid; Palmitic Acid; Peroxides; Protein Kinase C; Tumor Cells, Cultured

Both n-6 and n-3 polyunsaturated fatty acids are dietary fats important for cell function, being involved in several physiologic and pathologic processes, such as tumorigenesis. Linoleic acid and conjugated linoleic acid, its geometrical and positional stereoisomer, were tested on several human tumor cell lines originating from different tissues and with different degrees of malignancy. This was to provide the widest possible view of the impact of dietary lipids on tumor development. While linoleic acid exerted different effects, ranging from inhibitory to neutral, even promoting growth, conjugated linoleic acid inhibited growth in all lines tested and was particularly effective against the more malignant cells, with the exception of mammary tumor cells, in which behavior was the opposite, the more malignant cell line being less affected. The inhibitory effect of conjugated linoleic acid on growth may be accompanied by different contributions from apoptosis and necrosis. The effects of conjugated linoleic acid on growth or death involved positive or negative variations in PPARs. The important observation is that a big increase of PPARalpha protein occurred in cells undergoing strong induction of apoptosis, whereas PPARbeta/delta protein decreased. Although PPARalpha and PPARbeta/delta seem to be correlated to execution of the apoptotic program, the modulation of PPARgamma appears to depend on the type of tumor cell, increasing as protein content, when inhibition of cell proliferation occurred. In conclusion, CLA may be regarded as a component of the diet that exerts antineoplastic activity and its effect may be antiproliferative or pro-apoptotic.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Carcinoma; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Linoleic Acid; Linoleic Acids, Conjugated; Liver Neoplasms; Necrosis; Neoplasms; Peroxisome Proliferator-Activated Receptors; PPAR alpha; PPAR delta; PPAR gamma; PPAR-beta; Urinary Bladder Neoplasms

We showed the inhibitory effect of oleic and palmitoleic acids (OA and POA) on this trans10, cis12 (10t, 12c)-CLA induced cytotoxic activity. When cells were cultured in the presence of 10t, 12c-CLA, this potent cytotoxic effect on dRLh-84 cells was clearly obvious when compared to the control vehicle group. It was revealed that the levels of cellular OA and POA levels decreased upon cis9, trans11 (9c,11t) or 10t, 12c-CLA treatment in a time course dependent manner. OA or POA demonstrates a dose dependent inhibition of the 10t, 12c-CLA induced cytotoxicity. Notable nuclear fragmentation or activation of caspase-3 and 9 by 10t, 12c-CLA in dRLh-84 was counteracted by treatment with OA or POA. Results also suggest that 10t, 12c-CLA induced apoptosis can be inhibited by treatment with OA or POA.

Topics: Animals; Caspase 3; Caspase 9; Caspases; Fatty Acids, Monounsaturated; Linoleic Acid; Liver Neoplasms; Liver Neoplasms, Experimental; Oleic Acid; Rats; Tumor Cells, Cultured

We investigated the growth inhibitory effect of conjugated linoleic acid (CLA) on HepG2 (human hepatoma cell line), exploring whether the inhibitory action occurs via lipid peroxidation in the cells. When the cells were incubated up to 72 h with 5-40 microM of CLA (a mixture of 9c,11t-18:2 and 10t,12c-18:2), cell proliferation was clearly inhibited in a dose and time dependent manner but such an inhibition was not confirmed with linoleic acid (LA). In order to evaluate the possible contribution of lipid peroxidation exerted by CLA to cell growth inhibition, alpha-tocopherol (5-20 microM) and BHT (1-10 microM) as potent antioxidants were added to the medium with CLA (20 microM), which did not restore cell growth at all. Furthermore, after 72 h incubation, the membranous phospholipid hydroperoxide formation in the CLA-supplemented cells was suppressed respectively to 25% and 50% of that in LA-supplemented cells and control cells. No difference was observed by a conventional lipid peroxide assay, the TBA test, between CLA-supplemented cells and LA-supplemented cells. Although the cellular lipid peroxidation was not stimulated, lipid contents (triacylglycerol, total cholesterol and free cholesterol) and fatty acid contents (palmitic acid, palmitoleic acid and stearic acid) markedly increased in CLA-supplemented cells compared with LA-supplemented and control cells. Moreover, supplementation with 20 microM LA and 20 microM arachidonic acid profoundly interfered with the inhibitory effect of CLA in HepG2. These results suggest that the growth inhibitory effect of CLA on HepG2 is due to changes in fatty acid metabolism but not to lipid peroxidation.

Topics: Antioxidants; Carcinoma, Hepatocellular; Cell Line; Cholesterol; Culture Media; Fatty Acids; Humans; Linoleic Acid; Lipid Peroxidation; Liver Neoplasms; Phospholipids; Thiobarbituric Acid Reactive Substances; Triglycerides

Some fatty acids are reported to inhibit tumor growth of pancreatic carcinoma. However, it is still unknown if alpha-linolenic acid (ALA) and linoleic acid (LA) inhibit liver metastasis of ductal pancreatic adenocarcinoma. Therefore we studied the effect of these fatty acids on liver metastasis in the animal model of N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic adenocarcinoma in Syrian hamsters. Since lipid peroxidation seems to be involved in carcinogenesis and metastasis, we further analyzed the intrahepatic concentration of thiobarbituric acid-reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). We observed an increase in the incidence and the number of liver metastases in response to the combination of ALA and LA. This was accompanied by a decrease in hepatic GSH-Px activity and an increase in hepatic SOD activity and TBARS concentration. The increase in hepatic lipid peroxidation seems to be one possible mechanism of increasing liver metastasis in this study.

Topics: Adenocarcinoma; alpha-Linolenic Acid; Animals; Cricetinae; Dietary Fats, Unsaturated; Glutathione Peroxidase; Linoleic Acid; Lipid Peroxidation; Liver; Liver Neoplasms; Male; Mesocricetus; Nitrosamines; Pancreas; Pancreatic Neoplasms; Random Allocation; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Review of the evidence available in published literature supports a radical change in viewpoint with respect to disease in countries where maize is the predominant dietary component. In these countries, the pattern of disease is largely determined by a change in immune profile caused by metabolites of dietary linoleic acid. High intake of linoleic acid in a diet deficient in other polyunsaturated fatty acids and in riboflavin results in high tissue production of prostaglandin E2, which in turn causes inhibition of the proliferation and cytokine production of Th1 cells, mediators of cellular immunity. Tuberculosis, measles, hepatoma, secondary infection in HIV and kwashiorkor are all favoured by this reduction in cellular immunity. Diet-associated inhibition of the Th1 subset is a major contributor to the high prevalence of these diseases found in areas of sub-Saharan Africa where maize is the staple.

Topics: Africa; Dinoprostone; HIV Infections; Humans; Immunity, Cellular; Kwashiorkor; Linoleic Acid; Liver Neoplasms; Measles; Th1 Cells; Tuberculosis; Zea mays

The present study was undertaken to examine the cellular uptake of stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic acid (18:3), and their effects on synthesis and secretion of lipids in Hep-G2 cells. The cells were grown for 6 days in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum. On day 7, cells were incubated in a serum-free DMEM containing 0.25-1.0 mM of 18:0, 18:1, 18:2 or 18:3. The cellular uptake of these fatty acids was almost linear during the 4 hr incubation period, and no significant differences were noted among the fatty acids tested, regardless of their degree of unsaturation. The treatment of cells with 1.0 mM of these fatty acids stimulated triglyceride (TG) synthesis nearly ten-fold and phospholipid (PL) synthesis approx, two-fold compared with those of the control. The lipoprotein-TG secretion also increased and was the highest with 18:1 followed in descending order by 18:2, 18:3, and 18:0. The fatty acid treatment of cells also significantly increased the incorporation of 14C-acetate into the cellular and lipoprotein cholesterol compared with that of the control (p < 0.05). In addition, notable changes occurred in the fatty acid composition of cellular and medium lipids, which were enriched with the particular fatty acid present in the incubation medium. The findings that 18:0, 18:1, 18:2, and 18:3 were taken up by Hep-G2 cells at almost identical rates demonstrate that differences in the cellular synthesis of lipids and their secretion are attributable to the metabolic specificity of those fatty acids, rather than variable rates of their uptake.

Topics: Acetates; alpha-Linolenic Acid; Carcinoma, Hepatocellular; Cell Division; Cell Survival; Cholesterol; Chromatography, Thin Layer; Fatty Acids; Glycerol; Humans; Linoleic Acid; Liver; Liver Neoplasms; Oleic Acid; Phospholipids; Stearic Acids; Triglycerides; Tumor Cells, Cultured

The effects of eicosapentaenoic acid [EPA; n-3 polyunsaturated fatty acid (PUFA)], linoleic acid (LA; n-6 PUFA), and palmitic acid (PA; saturated fatty acid) on 1,2-dimethylhydrazine-induced F344 rat colon carcinoma cells (ACL-15) were investigated in vivo and in vitro. The number and size of liver metastatic foci via a superior mesenteric vein injection of ACL-15 cells in F344 rats were significantly inhibited in the EPA-treated group compared with the LA-treated group (p < 0.01); the PA-treated animals and those fed commercial rodent chow (standard diet) demonstrated intermediate values. In a dot immunoblotting assay, vascular cell adhesion molecule 1 expression on ACL-15 cells was downregulated by EPA-ethyl ester treatment and upregulated by LA-ethyl ester treatment compared with the untreated control cells, whereas the expression of matrix metalloproteinase 1 and 2 was not influenced by the fatty acid ethyl esters. In a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, EPA-ethyl ester suppressed ACL-15 cell growth in a schedule-dependent manner, and LA-ethyl ester showed schedule-dependent stimulation. In contrast, PA demonstrated no regulatory effect on cell growth at lower concentrations (< or = 5 mg/ml) but concentration-dependent inhibition at higher concentrations. According to our in vivo cell kinetic study, the difference in tumor growth at the metastatic site was due to different tumor cell proliferation rates; the cell loss rate was not altered. Therefore, the inhibitory effect of liver metastasis on ACL-15 cells by EPA can be explained by a decreased ability of tumor cell adhesion to the capillary bed (low expression of vascular cell adhesion molecule 1) and a lower potential of tumor cell proliferation (low mitotic rate) at the secondary site.

Topics: Animals; Colonic Neoplasms; Dietary Fats; Eicosapentaenoic Acid; Fatty Acids; Linoleic Acid; Liver Neoplasms; Male; Palmitic Acid; Rats; Rats, Inbred F344; Tumor Cells, Cultured

We have studied the biosynthesis of long chain polyunsaturated fatty acids (LC-PUFA) from their precursors in cultured cells undergoing physiological modifications, or under the influence of lipid-lowering drugs or ethanol. The formation of arachidonic acid (AA, 20:4 n-6) from the percursor linoleic acid (LA, 18:2 n-6) in the neuroblastoma cells SK-N-BE is enhanced at early stages of differentiation, and declines when differentiation is complete, in concomitance with maximal accumulation of AA in cell lipids. In the monocytic cells THP-1, the biosynthesis of LC-PUFA is also enhanced by treatment with the HMGCoA reductase inhibitor simvastatin (S), an effect which is reverted by mevalonate and other intermediates of cholesterol synthesis. Maximal activation of LC-PUFA synthesis by S occurs at concentrations lower than those required for maximal inhibition of cholesterol synthesis. In the hepatoma cells HepG2, ethanol decreases the biosynthesis of LC-PUFA while potentiating the incorporation of acetate into cholesterol. LC-PUFA synthesis appears thus to be modulated in the course of cell differentiation and complex interactions between LC-PUFA and cholesterol synthesis occur, as judged from data obtained through pharmacological manipulations.

Topics: Arachidonic Acid; Carcinoma, Hepatocellular; Cell Differentiation; Cell Line; Cholesterol; Enzyme Inhibitors; Ethanol; Fatty Acids, Unsaturated; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Linoleic Acid; Linoleic Acids; Liver Neoplasms; Lovastatin; Mevalonic Acid; Monocytes; Neuroblastoma; Simvastatin; Tumor Cells, Cultured

The fasting concentration of free fatty acids (FFA) in the ascitic fluid was determined in 14 patients with malignant ascites and in 19 patients with liver cirrhosis. In malignant ascites FFA levels were increased more than three times when compared with the levels in cirrhotic ascites (5.241 +/- 0.493 vs. 1.558 +/- 0.170 mumol/ml; P < 0.0001). Palmitic acid was the most representative saturated FFA (which together accounted for 2.499 +/- 0.323 vs. 0.833 +/- 0.064 mumol/ml; P < 0.0001), while unsaturated FFA (2.741 +/- 0.298 vs. 0.725 +/- 0.111 mumol/ml; P < 0.001) were represented, in decreasing order, by oleic, linoleic and arachidonic acids. The ratio of unsaturated to saturated FFA was higher in neoplastic patients (1.35 +/- 0.29 vs. 0.826 +/- 0.065 P < 0.05). Albumin concentration in ascitic fluid of neoplastic patients was 22.44 +/- 1.35 g/l, while that of cirrhotic patients was 8.19 +/- 0.32 g/l, P < 0.0001. A close relationship (R2 = 95.14%) between albumin concentration in ascitic fluid and levels of total FFA was found. These data support the hypothesis that the elevation of FFA in ascitic fluid allows discrimination between malignant and non-malignant ascites.

Topics: Adult; Aged; Albumins; Arachidonic Acid; Ascitic Fluid; Carcinoma, Hepatocellular; Fatty Acids, Nonesterified; Female; Humans; Linoleic Acid; Linoleic Acids; Liver Cirrhosis; Liver Neoplasms; Male; Middle Aged; Oleic Acid; Oleic Acids; Palmitic Acid; Palmitic Acids; Peritoneal Neoplasms

The protective influence of bovine serum albumin against growth inhibition caused by fatty acids was studied in human hepatoma (HepG2) and immortalized human kidney epithelial (IHKE) cells. In general, growth inhibition by unsaturated fatty acids (0.15 mmol/liter) increased with increasing number of double bonds. For HepG2 cells crude albumin (1 g/100 ml) did not greatly modify growth inhibition by arachidonic, eicosapentaenoic, and docosahexaenoic acid. With oleic, linoleic, and linolenic acids, crude and defatted albumin stimulated cell growth. In contrast, for IHKE cells both albumins counteracted growth inhibition by unsaturated fatty acids to approximately the same extent. When HepG2 cells were cultured in the presence of saturated fatty acids (0.3 mmol/liter), C2, C6, and C8 had no or little inhibitory effect. C10 and C12 inhibited cell growth appreciably, whereas C14, and especially C16, had poor inhibitory effects. Crude albumin counteracted growth inhibition by all these fatty acids. In contrast, defatted albumin had little or no effect (except against C10 and C12), and even increased the growth inhibition by C14 and C16. With unsaturated fatty acids there seemed to be an inverse relationship between cell growth and the concentration of thiobarbituric acid reactive substances (TBARS) in media. Vitamin E abolished growth inhibition (and the increase in TBARS concentration) by unsaturated fatty acids. The complex interaction between fatty acids and albumins calls for great caution when interpreting data on growth effects.

Topics: alpha-Linolenic Acid; Arachidonic Acid; Carcinoma, Hepatocellular; Cell Division; Cell Line, Transformed; Docosahexaenoic Acids; Eicosapentaenoic Acid; Epithelial Cells; Fatty Acids; Humans; Kidney; Linoleic Acid; Linoleic Acids; Liver Neoplasms; Oleic Acid; Oleic Acids; Serum Albumin, Bovine; Thiobarbituric Acid Reactive Substances; Tumor Cells, Cultured

The effect of lovastatin (LOV), the inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, on linoleic acid (LA, 18:2n-6) metabolism was examined in human monocytic Mono Mac 6 (MM6) and hepatoma Hep G2 cells. The desaturation of LA was examined after LOV (72 h, 10 microM) or dimethylsulfoxide (LOV carrier, < 0.1%) and [14C]LA (last 18 h, 0.3 microCi, 5 microM). In both cell lines, LOV reduced the percentage of 14C label associated with LA and increased the percentage of label in the 20:4n-6 and the 22:5n-6 fractions. In Hep G2 but not MM6 cells, this effect was fully reversible by means of coincubation with mevalonic acid (500 microM), but not with cholesterol or lipoproteins. In both cell lines, the LOV-mediated increase in LA desaturation resulted in dose-dependent reductions of LA and elevations of AA in cellular phospholipids. The lipids secreted by LOV-treated Hep G2 cells were also enriched in arachidonic acid (AA). In the MM6 cells, LOV increased release of thromboxane upon stimulation with the calcium ionophore A23187. In summary, our findings of higher LA desaturation and AA enrichment of lipids secreted by the Hep G2 cells suggest that LOV treatment may increase the delivery of AA from the liver to extrahepatic tissues. The changes in membrane fatty acid composition can influence a variety of cellular functions, such as eicosanoid synthesis in monocytic cells. The mechanism appears to be related to the reduced availability of intermediates of cholesterogenesis.

Topics: Analysis of Variance; Arachidonic Acid; Carcinoma, Hepatocellular; Cell Line; Cholesterol; Cholesterol Esters; Fatty Acids; Humans; Kinetics; Linoleic Acid; Linoleic Acids; Liver; Liver Neoplasms; Lovastatin; Monocytes; Phospholipids; Thromboxanes; Triglycerides; Tumor Cells, Cultured

Excretion of methylmalonic acid by vitamin E-deficient patients and decreased labeling of adenosylcobalamin (AdoCbl) from cyanocobalamin in vitamin E-deficient rats suggest an interaction of vitamins E and B-12. We studied this interaction in two human cell culture systems: foreskin fibroblasts and a hepatoma cell line (HepG2). We measured radiolabeling of AdoCbl and methylcobalamin from [57Co]hydroxycobalamin for 6 d in the presence and absence of linoleate (an oxidative stressor) and alpha-tocopherol. In both cell types, labeling of AdoCbl was lower in the presence of linoleate unless alpha-tocopherol was present. The decrease was accentuated by peroxidized linoleic acid; AdoCbl synthetic rate was inversely associated with thiobarbituric acid-reactive compound concentration. Subcellular partitioning of labeled cobalamin revealed less in mitochondria in the linoleate-stressed cells that were not treated with alpha-tocopherol. We conclude that lipoperoxidation reduces mitochondrial AdoCbl formation and that alpha-tocopherol exerts a protective effect in oxidatively stressed cells. We suggest that this subcellular deficiency in AdoCbl may be one mechanism by which vitamin E deficiency leads to neurologic injury. The mechanism seems primarily to involve an alteration in intracellular cobalamin distribution with perhaps a minor effect upon enzymes of AdoCbl synthesis.

Topics: Carcinoma, Hepatocellular; Cells, Cultured; Cobamides; Fibroblasts; Humans; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Liver Neoplasms; Oxidation-Reduction; Tumor Cells, Cultured; Vitamin E

Incorporation and metabolism of gamma-linolenic acid (GLA) in both rat hepatocytes and Hep G2 cells were compared to those of oleic (OA), linoleic (LA), alpha-linolenic (LLA), and dihomo-gamma-linolenic (DGLA) acids. The incorporation of GLA into both types of cells was higher than LLA and DGLA, but lower than OA and LA. It was efficiently converted into DGLA in both types of cells and increased the concentration of DGLA. LLA was converted to a small amount of C20:4 (n-3) only in Hep G2 cells. Incubation with LA, GLA, LLA, and DGLA did not increase the concentration of arachidonic acid (AA) in both types of cells. LA. GLA, LLA, and their metabolites were incorporated into phosphatidylcholine, but only GLA and its metabolite, DGLA, were also incorporated into phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol. The coexistence of GLA and LLA during their catabolism diminished the amounts of respective metabolite in Hep G2 cells. The presence of GLA inhibited completely the formation of C20:4(n-3) from LLA. The results indicate that GLA is more effective in raising the ratio of DGLA/AA. Also, polyunsaturated fatty acids of n-3 and n-6 series have competitively catabolized in both types of hepatocytes.

Topics: 8,11,14-Eicosatrienoic Acid; alpha-Linolenic Acid; Animals; Carcinoma, Hepatocellular; gamma-Linolenic Acid; Humans; Linoleic Acid; Linoleic Acids; Linolenic Acids; Liver; Liver Neoplasms; Oleic Acid; Oleic Acids; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylinositols; Phosphatidylserines; Rats; Tumor Cells, Cultured

In previous communications the growth-suppressive effect of gamma-linolenic acid (GLA) dissolved in sodium carbonate in the culture media of malignant cells has been reported. In this study we show that linoleic acid (LA), the fatty acid precursor of GLA, had no growth-suppressive effect on human hepatoma cells in culture while a similar concentration of GLA suppressed malignant cell growth in culture by 69% after 10 days. This growth-suppressive effect must therefore be seen as an effect of GLA and not as a 'soap' effect. It has also been shown that the growth rate of human hepatoma cells in culture to which GLA was added daily for 5 consecutive days remained suppressed after the withdrawal of GLA from the growth medium for a further 5-day period. The striking difference between GLA and LA as regards growth suppression of human hepatoma cells in culture appears to imply a metabolic block in the hepatoma cells, involving the enzyme delta-6-desaturase, in the conversion of LA to GLA and thence via dihomo-gamma-linolenic acid to the prostaglandins of the 1 series.

Topics: Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Count; Cell Division; Cells, Cultured; Culture Media; gamma-Linolenic Acid; Humans; Linoleic Acid; Linoleic Acids; Linolenic Acids; Liver Neoplasms; Microscopy, Phase-Contrast