linoleic-acid and Glioma

In vitro and in vivo studies have shown that gamma-linoleic acid (GLA), arachidonic acid (AA) and eicosapentaenoic acid (EPA) can selectively kill tumor cells. In a clinical trial, the effectiveness of intratumoral administration of GLA in patients with gliomas was studied. Of the 6 patients treated, all showed substantial response to GLA as documented by computerized tomography. There were no acute side-effects due to the therapy. This report demonstrates that intratumoral administration of GLA is a possible approach to the treatment of human glial tumors.

Topics: Adolescent; Adult; Antineoplastic Agents; Brain Neoplasms; Glioma; Humans; Injections, Intraventricular; Linoleic Acid; Linoleic Acids; Male; Middle Aged

The relationship between glioblastoma (GBM) and fatty acid metabolism could be the key to elucidate more effective therapeutic targets. 15-lipoxygenase-1 (15-LOX), a linolenic acid and arachidonic acid metabolizing enzyme, induces both pro- and antitumorigenic effects in different cancer types. Its role in glioma activity has not yet been clearly described. The objective of this study was to identify the influence of 15-LOX and its metabolites on glioblastoma cell activity.. GBM cell lines were examined using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to identify 15-LOX metabolites. GBM cells treated with 15-LOX metabolites, 13-hydroxyoctadecadeinoic acid (HODE) and 9-HODE, and two 15-LOX inhibitors (luteolin and nordihydroguaiaretic acid) were also examined. Dose response/viability curves, RT-PCRs, flow cytometry, migration assays, and zymograms were performed to analyze GBM growth, migration, and invasion.. Higher quantities of 13-HODE were observed in five GBM cell lines compared to other lipids analyzed. Both 13-HODE and 9-HODE increased cell count in U87MG. 15-LOX inhibition decreased migration and increased cell cycle arrest in the G2/M phase.. 15-LOX and its linoleic acid (LA)-derived metabolites exercise a protumorigenic influence on GBM cells in vitro. Elevated endogenous levels of 13-HODE called attention to the relationship between linoleic acid metabolism and GBM cell activity.

Topics: Arachidonate 15-Lipoxygenase; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; G2 Phase Cell Cycle Checkpoints; Glioblastoma; Glioma; Humans; Linoleic Acid; Linoleic Acids; Linoleic Acids, Conjugated; Lipoxygenase Inhibitors

The mitochondrial phospholipid cardiolipin (CL) has been implicated with mitochondrial morphology, function, and cell proliferation. Changes in CL are often paralleled by changes in the lipid environment of mitochondria that may contribute to mitochondrial function and proliferation. This study aimed to separate the effects of CL content and CL composition from cellular free fatty acid distribution on bioenergetics and proliferation in C6 glioma cells. To this end, cardiolipin synthase and the CL remodelling enzyme, tafazzin, were knocked-down by siRNA in C6 cells. After 72 h of cultivation, we analysed CL composition by means of LC/MS/MS, distribution of cellular fatty acids by means of gas chromatography, and determined oxygen consumption and proliferation. Knock-down of cardiolipin synthase affected the cellular CL content in the presence of linoleic acid (LA) in the culture medium. Knock-down of tafazzin had no consequence with respect to the pattern of cellular fatty acids but caused a decrease in cell proliferation. It significantly changed the distribution of molecular CL species, increased CL content, decreased oxygen consumption, and decreased cell proliferation when cultured in the presence of linoleic acid (LA). The addition of linoleic acid to the culture medium caused significant changes in the pattern of cellular fatty acids and the composition of molecular CL species. These data suggest that tafazzin is required for efficient bioenergetics and for proliferation of glioma cells. Supplementation of fatty acids can be a powerful tool to direct specific changes in these parameters.

Topics: Acyltransferases; Animals; Brain Neoplasms; Cardiolipins; Cell Line, Tumor; Cell Proliferation; Citrate (si)-Synthase; Gene Knockdown Techniques; Glioma; Linoleic Acid; Membrane Proteins; Mitochondria; Rats; RNA, Messenger; RNA, Small Interfering; Transcription Factors; Transferases (Other Substituted Phosphate Groups)

Glioma cells not only secrete high levels of vascular endothelial growth factor (VEGF) but also express VEGF receptors (VEGFR), supporting the existence of an autocrine loop. The direct impact on glioma cells metabolism of drugs targeting the VEGF pathway, such as Bevacizumab (Bev) or VEGFR Tyrosine Kinase Inhibitor (TKI), is poorly known.. U87 cells were treated with Bev or SU1498, a selective VEGFR2 TKI. VEGFR expression was checked with FACS flow cytometry and Quantitative Real-Time PCR. VEGF secretion into the medium was assessed with an ELISA kit. Metabolomic studies on cells were performed using High Resolution Magic Angle Spinning Spectroscopy (HR-MAS).. U87 cells secreted VEGF and expressed low level of VEGFR2, but no detectable VEGFR1. Exposure to SU1498, but not Bev, significantly impacted cell proliferation and apoptosis. Metabolomic studies with HR MAS showed that Bev had no significant effect on cell metabolism, while SU1498 induced a marked increase in lipids and a decrease in glycerophosphocholine. Accordingly, accumulation of lipid droplets was seen in the cytoplasm of SU1498-treated U87 cells.. Although both drugs target the VEGF pathway, only SU1498 showed a clear impact on cell proliferation, cell morphology and metabolism. Bevacizumab is thus less likely to modify glioma cells phenotype due to a direct therapeutic pressure on the VEGF autocrine loop. In patients treated with VEGFR TKI, monitoring lipids with magnetic resonance spectroscopic (MRS) might be a valuable marker to assess drug cytotoxicity.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Apoptosis; Bevacizumab; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Shape; Cinnamates; Glioma; Humans; Least-Squares Analysis; Linoleic Acid; Lipids; Magnetic Resonance Spectroscopy; Principal Component Analysis; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2

Considering the observations that linoleic acid conjugated with paclitaxel (CLA-PTX) possesses antitumor activity against brain tumors, is able to cross the blood-brain barrier, but has poor water solubility, the purpose of this study was to prepare a novel CLA-PTX microemulsion and evaluate its activity against brain tumors in vitro and in vivo.. The in vitro cytotoxicity of a CLA-PTX microemulsion was investigated in C6 glioma cells. The in vivo antitumor activity of the CLA-PTX microemulsion was evaluated in tumor-bearing nude mice and rats. The pharmacokinetics of the CLA-PTX microemulsion were investigated in rats, and its safety was also evaluated in mice.. The average droplet size of the CLA-PTX microemulsion was approximately 176.3 ± 0.8 nm and the polydispersity index was 0.294 ± 0.024. In vitro cytotoxicity results showed that the IC(50) of the CLA-PTX microemulsion was 1.61 ± 0.83 μM for a C6 glioma cell line, which was similar to that of free paclitaxel and CLA-PTX solution (P > 0.05). The antitumor activity of the CLA-PTX microemulsion against brain tumors was confirmed in our in vivo C6 glioma tumor-bearing nude mice as well as in a rat model. In contrast, Taxol(®) had almost no significant antitumor effect in C6 glioma tumor-bearing rats, but could markedly inhibit growth of C6 tumors in C6 glioma tumor-bearing nude mice. The pharmacokinetic results indicated that CLA-PTX in solution has a much longer circulation time and produces higher drug plasma concentrations compared with the CLA-PTX microemulsion. The results of the acute toxicity study showed that the LD(50) of CLA-PTX solution was 103.9 mg/kg. In contrast, the CLA-PTX microemulsion was well tolerated in mice when administered at doses up to 200 mg/kg.. CLA-PTX microemulsion is a novel formulation with significant antitumor efficacy in the treatment of brain tumors, and is safer than CLA-PTX solution.

Topics: Animals; Antineoplastic Agents, Phytogenic; Brain Neoplasms; Cell Line, Tumor; Dose-Response Relationship, Drug; Emulsions; Glioma; Lethal Dose 50; Linoleic Acid; Mice; Nanocapsules; Paclitaxel; Treatment Outcome

Docosahexaenoic acid (DHA) may have potential anticarcinogenic effect. In the present study, effect of DHA on rat C6 glioma was tested. In vitro, cytotoxic effect of 50-400 microM DHA on C6 cells was evaluated and compared with linoleic acid (LA). In vivo, adult female Wistar rats implanted with C6 tumor, fed 1 ml of DHA oil (containing 73% DHA, 36 rats) or LA oil (containing 72-77% LA, 41 rats) daily, starting one week prior to tumor implantation until death or if survived, until 30 days after implantation. Another group of tumor bearing rats was treated with chloroethyl-cyclohexyl-nitrosourea (CCNU, 30 mg/kg, 31 rats) at day 8 post implantation to show if the result of oil supplementation is comparable to single agent chemotherapy. mRNA expression of p21 and p27 was determined in vitro at 100 and 150 microM of fatty acids and in tumors of rats supplemented with LA or DHA oils. In vitro, DHA, but not LA, had cytotoxic effect on C6 cells at 200 and 400 microM and DHA increased mRNA expression of p21 at 150 microM (p < 0.05). In rat glioma model, although a non-significant trend towards better survival was observed in DHA oil relative to LA oil group, the difference was not significant (p = 0.20). p21 and p27 mRNA expression in tumors of DHA oil group did not differ with LA oil group. Single dose of CCNU increased survival when compared to LA oil group (p < 0.001). In conclusion, intake of DHA at the dose or duration employed in the present study might be insufficient to bring about its cytotoxic action on rat's C6 brain tumor.

Topics: Animals; Antineoplastic Agents; Body Weight; Brain Neoplasms; Cell Line, Tumor; Cell Survival; Cyclin-Dependent Kinase Inhibitor p27; Diet; Docosahexaenoic Acids; Eating; Fatty Acids; Female; Glioma; Linoleic Acid; Neoplasm Transplantation; p21-Activated Kinases; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Survival Analysis

Experimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo.. GLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL/rat/day) starting one week prior to C6 glioma cells implantation and continued for two weeks after implantation. Control group were fed same amount of high linoleic acid safflower oil (74-77% linoleic acid). Fatty acid composition of tumor samples was determined in a set of 8-12 animals in each group and serum fatty acid in 6 animals per each group. Gene expression of tumor fatty acid binding protein 7 (FABP7), epidermal growth factor receptor (EGFR), peroxisome proliferator activated receptor gamma (PPAR-gamma) and retinoid x receptor-alpha (RXR-alpha) were determined in a set of 18 animals per group.. DHAO feeding increased EPA of brain tumors and decreased ratio of n-6/n-3 fatty acids. Serum levels of EPA were also increased in DHAO group. A similar trend in serum and tumor levels of DHA were observed in DHAO group but it did not achieve statistical significance. GLAO increased serum concentration of GLA but had no significant effect on tumor GLA or dihomo-gamma linolenic acid (DGLA) concentrations. Gene expression of FABP7 was up-regulated in tumors of DHAO group but no other significant effects were observed on EGFR, PPAR-gamma or RXR-alpha expression, and expression of these genes in tumors of GLAO were not different from SFO group.. Dietary supplementation of DHA containing oil could be an effective way to increase levels of long chain n-3 fatty acids in brain tumors and this increase may be mediated partly by up-regulation of FABP7 expression.

Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Chromatography, Gas; Docosahexaenoic Acids; Fatty Acid-Binding Protein 7; Fatty Acid-Binding Proteins; Fatty Acids; Female; gamma-Linolenic Acid; Gene Expression; Genes, erbB-1; Glioma; Linoleic Acid; Lipid Metabolism; Nerve Tissue Proteins; PPAR gamma; Rats; Rats, Wistar; Retinoid X Receptor alpha; Reverse Transcriptase Polymerase Chain Reaction

In this study, the role of exogenous fatty acids in the regulation of proteolipid protein (PLP) gene expression was investigated using the following model culture system: C6 glioma cells expressing the green-fluorescent protein (eGFP) driven by different segments of PLP promoter. Eicosapentanoic acid (EPA; 20:5 n-3), but not arachidonic acid (AA; 20:4 n-6), induced a significant increase in medium fluorescence intensity (MFI) determined by fluorescence-activated cell sorting (FACS). The induction of PLP promoter was time-dependent showing maximal activity between 24 and 48 h after EPA exposure. PLP promoter activation was dependent on fatty acid concentration, with maximum activation at 200 microM. Northern blot analysis confirmed the fluorescence data in C6 cells incubated with EPA. Furthermore, this treatment increased the adenylyl cyclase-cyclic AMP (cAMP) levels and the mitogen-activated protein kinase (MAPK) activation in C6 cells. PLP promoter activity was inhibited by pre-treatment with H89 (protein kinase A (PKA) inhibitor), but not with PD98059 (MAPK inhibitor), suggesting that EPA stimulates the expression of PLP via cAMP-mediated pathways.

Topics: alpha-Linolenic Acid; Animals; Arachidonic Acid; Blotting, Northern; Blotting, Western; Brain Neoplasms; Cell Line, Tumor; Cells, Cultured; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Glioma; Green Fluorescent Proteins; Linoleic Acid; Luminescent Proteins; Mitogen-Activated Protein Kinases; Myelin Proteolipid Protein; Rats; RNA, Messenger; Stimulation, Chemical; Transfection

The effect of arachidonic acid (AA, 20:4) was analyzed in vitro by employment of C6 glioma cells and astrocytes from primary culture. The cells were suspended in an incubation chamber under continuous control of pH, pO2, and temperature. Cell swelling was quantified by flow cytometry. After a control period, the suspension was added with AA at concentrations of 0.01 to 1.0 mM. Administration of AA induced an immediate, dose dependent swelling in C6 glioma cells or astrocytes. AA-concentrations of 0.01 mM led to an increase of the glial cell volume to 103.0 +/- 1.0% of control, 0.1 mM to 110.0 +/- 1.5%, and 1.0 mM to 118.8 +/- 1.5% within 10 min. The swelling response to linoleic acid (18:2) was only about half of what was found when AA was administered at a concentration of 0.1 mM, whereas stearic acid (18:0) did not induce any cell volume changes. Inhibition of the cyclo- and lipoxygenase pathway by BW 755C did not prevent glial swelling from AA, whereas it was reduced by SOD, or almost completely abolished by the aminosteroid U-74389F, an antagonist of lipid peroxidation. Replacement of Na(+)- and Cl- -ions in the suspension medium by choline chloride was also associated with complete abolishment of cell swelling from AA. The results demonstrate an impressive efficacy of arachidonic acid to induce glial swelling which might be attributable to activation of lipid peroxidation by the fatty acid, leading to an increased Na(+)-permeability and subsequent influx of water into the cells.

Topics: Animals; Arachidonic Acid; Astrocytes; Brain Neoplasms; Cell Line; Cell Membrane Permeability; Dose-Response Relationship, Drug; Flow Cytometry; Glioma; Intracellular Fluid; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Neuroglia; Neurons; Rats; Sodium; Tumor Cells, Cultured; Water-Electrolyte Balance

We have investigated the mechanism by which the rat glioblastoma C6 cell line resistant to doxorubicin presented an increase of free fatty acid utilization from the nutrient source as compared to the wild sensitive strain. We have shown that this was not due to an accelerated turnover of the phospholipid hydrophobic or hydrophilic moieties, but to an important increase of the uptake of the free fatty acids. This was demonstrated by studies performed with linoleic and linolenic acids during very short incubations, at low temperatures, and in the absence of albumin in the medium. This enhancement of free fatty acid uptake may explain the differences which exist in the acyl group composition of membrane lipids between doxorubicin-sensitive and -resistant C6 cells, because of the suppression of the essential fatty acid-deficient status of the cells.

Topics: Acetates; Acetic Acid; alpha-Linolenic Acid; Animals; Cell Line; Cell Membrane; Doxorubicin; Drug Resistance; Fatty Acids, Nonesterified; Glioma; Kinetics; Linoleic Acid; Linoleic Acids; Linolenic Acids; Phosphates; Phospholipids; Rats

In cultured neuroblastoma cells (N1E-115), the metabolism of the essential fatty acid, linoleic acid (18:2 (n-6)), to arachidonic acid (20:4(n-6)) can be altered by other fatty acids in a manner supporting a concerted action of the modulating fatty acid on the desaturation and chain elongation enzymes. In further examination of mechanisms involved, cultured glioma (C-6) or neuroblastoma-glioma hybrids (NG-108-15) cells showed similar patterns of activation by some fatty acids (e.g., 20:3(n-6) and 20:4(n-6)), and inhibition (e.g., 18:3(n-3) or 22:6(n-3)) or no effect (e.g., 18:1(n-9), 20:3(n-3)) by others. In contrast, only inhibition by 20:4(n-6) was seen in cultured HeLa cells, suggesting that the intracellular interactions may not be universal in all cell lines. For fatty acids that activate 20:4(n-6) formation, the lag observed when substrate and activator were administered simultaneously was eliminated by preincubation with activator. Maximal activation occurred within 4 h for neuroblastoma and 2 h for glioma; in each cell line activation declined steadily for 10 h after removal of the activator. Inhibition of protein synthesis did not alter activation. As 98% of the fatty acid incorporated was esterified to triacylglycerol or phospholipid and only the triacylglycerol mass expanded, several manipulations to potentially alter the flow of acyl chains between these lipid pools were evaluated using dual-label and pulse-chase experiments. Results suggested that competition between 18:2(n-6) utilization for esterification to phospholipid and the desaturation-chain elongation sequence as well as a more direct and specific interaction of certain fatty acids with the enzymes may influence 20:4(n-6) formation. A model to explain these observations is discussed.

Topics: Arachidonic Acid; Arachidonic Acids; Cell Line; Fatty Acids; Fatty Acids, Essential; Glioma; HeLa Cells; Humans; Kinetics; Linoleic Acid; Linoleic Acids; Neuroblastoma; Phospholipids; Triglycerides

Topics: alpha-Linolenic Acid; Animals; Cell Line; Cholesterol; Fluorides; Glioma; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Synthase; Kinetics; Linoleic Acid; Linoleic Acids; Linolenic Acids; Neoplasms, Experimental; Oxo-Acid-Lyases; Rats

Topics: Brain Neoplasms; Cholesterol; Chromatography; Chromatography, Gas; Ependymoma; Fatty Acids; Glioma; Glycerides; Linoleic Acid; Mice; Neoplasm Transplantation; Oleic Acid; Palmitic Acid; Phospholipids; Research; Stearic Acids