gamma-linolenic-acid and Glioma

Gamma-linolenic acid (GLA) induced apoptosis of tumor cells without harming normal cells. Both cyclo-oxygenase (COX) and lipoxygenase (LO) inhibitors did not inhibit the selective tumoricidal action of GLA in some, but not all, tumor cells suggesting that GLA by itself is active. In contrast, anti-oxidants such as vitamin E blocked the tumoricidal action of GLA. GLA-treated tumor but not normal cells produced a 2-3-fold increase in free radicals and lipid peroxides. GLA decreased the anti-oxidant content of tumor cells, expression of oncogenes ras, and Bcl-2, enhanced the activity of p53, protected normal cells and tissues from the toxic actions of radiation and anti-cancer drugs, enhanced the cytotoxic action of anti-cancer drugs and reversed tumor cell drug resistance. In the animal glioma model, GLA induced tumor regression and preserved the surrounding normal brain tissue. In three open-label clinical studies, intra-tumoral injection of GLA induced significant reduction of glioma without any significant side effects. The low neurotoxicity of GLA to normal brain neurons and selective activity against tumor cells suggests that it could be an effective anti-glioma molecule.

Topics: Animals; Antioxidants; Apoptosis; Brain Neoplasms; Cyclooxygenase Inhibitors; Free Radicals; gamma-Linolenic Acid; Glioma; HeLa Cells; HL-60 Cells; Humans; Lipid Peroxides; Lipoxygenase Inhibitors; Mice; Vitamin E

Malignant gliomas are among the most devastating of cancers and are a major cause of mortality in a young population with a median survival time of 9 months following cytoreductive surgery, radiotherapy and chemotherapy. Recent studies showed that polyunsaturated fatty acids especially gamma-linolenic acid (GLA) have selective tumoricidal action especially against malignant glioma cells both in vitro and in vivo. Limited open label clinical studies showed that intratumoral injection/infusion of GLA is safe and effective against malignant gliomas. In view of this, large-scale, double blind studies are needed to establish the usefulness of GLA in the treatment of malignant brain tumors.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Cytoprotection; gamma-Linolenic Acid; Glioma; Humans

Gliomas are primary brain tumours. Gamma-linolenic acid (GLA) exerts anti-proliferative effects. Several ruthenium-containing complexes have antiproliferative effects and can be used as adjuvant therapies in cisplatin-resistant cancer. The present study reports on the anti-proliferative properties and effects on tumour morphology of a novel diruthenium-GLA complex (Ru2GLA) and its comparison with GLA in the C6 rat glioma model both in vitro and in vivo.. In vitro and in vivo experiments were performed on C6 glioma rat cells, and in an orthotopic model.. Ru2GLA (100 μM) appears to be an inhibitor of C6 rat glioma cell proliferation. The nuclear area of Ru2GLA-treated cells was 2.18-times larger than that of control cells, suggesting DNA replication occurred but mitosis was blocked in the G2-M phase. Ru2GLA (2 mM) inhibited C6 cell proliferation in vivo and the changes in tumor morphology confirm both cellular uptake and collagen fibre-binding in the extracellular matrix.. Ru2GLA appears to be a low-toxicity drug and a potential candidate for anti-proliferative therapy of glioma.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Extracellular Matrix; Female; gamma-Linolenic Acid; Glioma; Rats; Ruthenium; Tumor Burden

Polyunsaturated fatty acids (PUFAs) such as γ-linolenic acid (GLA), arachidonic acid (AA) and docosahexaenoic acid (DHA) have cytotoxic action on glioma cells.. We evaluated the cytotoxic action of GLA, AA and DHA on glioma cells with specific reference to the expression of miRNAs. Relative expression of miRNAs were assessed by using high throughput nanocapillary real-time PCR. Most of the miRNA target genes that showed altered expression could be classified as apoptotic genes and were up-regulated by PUFA or temozolomide treatment, while similar treatments resulted in repression of the corresponding mRNAs, such as cox2, irs1, irs2, ccnd1, itgb3, bcl2, sirt1, tp53inp1 and k-ras.. Our results highlight involvement of miRNAs in the induction of apoptosis in glioma cells by fatty acids and temozolomide.

Topics: Antineoplastic Agents, Alkylating; Apoptosis; Apoptosis Regulatory Proteins; Arachidonic Acid; Cell Line, Tumor; Dacarbazine; Docosahexaenoic Acids; Down-Regulation; gamma-Linolenic Acid; Glioblastoma; Glioma; Humans; MicroRNAs; Neoplasm Proteins; Osmolar Concentration; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Temozolomide; Up-Regulation

The present study reports the synthesis of a novel compound with the formula [Ru(2)(aGLA)4Cl] according to elemental analyses data, referred to as Ru(2)GLA. The electronic spectra of Ru(2)GLA is typical of a mixed valent diruthenium(II,III) carboxylate. Ru(2)GLA was synthesized with the aim of combining and possibly improving the anti-tumour properties of the two active components ruthenium and gamma-linolenic acid (GLA). The properties of Ru(2)GLA were tested in C6 rat glioma cells by analysing cell number, viability, lipid droplet formation, apoptosis, cell cycle distribution, mitochondrial membrane potential and reactive oxygen species. Ru(2)GLA inhibited cell proliferation in a time and concentration dependent manner. Nile Red staining suggested that Ru(2)GLA enters the cells and ICP-AES elemental analysis found an increase in ruthenium from <0.02 to 425 mg/Kg in treated cells. The sub-G1 apoptotic cell population was increased by Ru(2)GLA (22 +/- 5.2%) when analysed by FACS and this was confirmed by Hoechst staining of nuclei. Mitochondrial membrane potential was decreased in the presence of Ru(2)GLA (44 +/- 2.3%). In contrast, the cells which maintained a high mitochondrial membrane potential had an increase (18 +/- 1.5%) in reactive oxygen species generation. Both decreased mitochondrial membrane potential and increased reactive oxygen species generation may be involved in triggering apoptosis in Ru(2)GLA exposed cells. The EC(50) for Ru(2)GLA decreased with increasing time of exposure from 285 microM at 24 h, 211 microM at 48 h to 81 microM at 72 h. In conclusion, Ru(2)GLA is a novel drug with antiproliferative properties in C6 glioma cells and is a potential candidate for novel therapies in gliomas.

Topics: Animals; Antineoplastic Agents; Apoptosis; Benzimidazoles; Cell Line, Tumor; Cell Proliferation; Flow Cytometry; G1 Phase; gamma-Linolenic Acid; Glioma; Membrane Potential, Mitochondrial; Organometallic Compounds; Oxazines; Rats; Reactive Oxygen Species; Ruthenium; Spectrophotometry, Atomic; Staining and Labeling

Gamma-linolenic acid is a known inhibitor of tumour cell proliferation and migration in both in vitro and in vivo conditions. The aim of the present study was to determine the mechanisms by which gamma-linolenic acid (GLA) osmotic pump infusion alters glioma cell proliferation, and whether it affects cell cycle control and angiogenesis in the C6 glioma in vivo.. Established C6 rat gliomas were treated for 14 days with 5 mM GLA in CSF or CSF alone. Tumour size was estimated, microvessel density (MVD) counted and protein and mRNA expression measured by immunohistochemistry, western blotting and RT-PCR.. GLA caused a significant decrease in tumour size (75 +/- 8.8%) and reduced MVD by 44 +/- 5.4%. These changes were associated with reduced expression of vascular endothelial growth factor (VEGF) (71 +/- 16%) and the VEGF receptor Flt1 (57 +/- 5.8%) but not Flk1. Expression of ERK1/2 was also reduced by 27 +/- 7.7% and 31 +/- 8.7% respectively. mRNA expression of matrix metalloproteinase-2 (MMP2) was reduced by 35 +/- 6.8% and zymography showed MMP2 proteolytic activity was reduced by 32 +/- 8.5%. GLA altered the expression of several proteins involved in cell cycle control. pRb protein expression was decreased (62 +/- 18%) while E2F1 remained unchanged. Cyclin D1 protein expression was increased by 42 +/- 12% in the presence of GLA. The cyclin dependent kinase inhibitors p21 and p27 responded differently to GLA, p27 expression was increased (27 +/- 7.3%) while p21 remained unchanged. The expression of p53 was increased (44 +/- 16%) by GLA. Finally, the BrdU incorporation studies found a significant inhibition (32 +/- 11%) of BrdU incorporation into the tumour in vivo.. Overall the findings reported in the present study lend further support to the potential of GLA as an inhibitor of glioma cell proliferation in vivo and show it has direct effects upon cell cycle control and angiogenesis. These effects involve changes in protein expression of VEGF, Flt1, ERK1, ERK2, MMP2, Cyclin D1, pRb, p53 and p27. Combination therapy using drugs with other, complementary targets and GLA could lead to gains in treatment efficacy in this notoriously difficult to treat tumour.

Topics: Animals; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin D1; gamma-Linolenic Acid; Glioma; Matrix Metalloproteinase 2; Mitogen-Activated Protein Kinase 3; Neovascularization, Pathologic; Proliferating Cell Nuclear Antigen; Rats; Retinoblastoma Protein; Tumor Suppressor Protein p53; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1

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

Arachidonic acid (AA) and Gamma linolenic acid have been shown to limit glioma cell growth, stimulate apoptosis and lipid peroxidation. However, brain tumours are characterised by cellular heterogeneity and responding cell populations have not been identified. Brain tumour samples from patients were disaggregated. In cell preparations from 7 gliomas, reactive oxygen species (ROS), morphology and plasma membrane integrity were monitored +/-18-36 microM AA for 15-120 min using flow cytometry. Basal oxidative activity related to cell size/morphology, small granular cells showed lower activity. AA stimulation of ROS formation depended on cell size/morphology. Large, less granular cells showed greater AA stimulation. In 17 gliomas, GFAP immunofluorescence was demonstrated in larger cell populations. The large GFAP positive cell population with low side scatter was the highest responding cell population, suggesting selective tumour cell sensitivity to AA induced ROS formation. ROS may have a role in AA induced cell death and anti-tumour activity of AA in glioma.

Topics: Antineoplastic Agents; Arachidonic Acid; Brain Neoplasms; Cell Death; Cell Division; gamma-Linolenic Acid; Glioma; Humans; In Vitro Techniques; Oxidation-Reduction; Reactive Oxygen Species

The (1)H spectrum of certain tumor cells, in vivo tumors, and their biopsies in vitro shows a narrow and intense resonance at 1.26 ppm, which has been assigned to the fatty acyl chain of triglycerides [nuclear magnetic resonance (NMR) visible mobile lipids, MLs]. We have used diffusion-weighted NMR spectroscopy to directly address the subcellular origin of MLs in the case of C6 cells in which lactate accumulation had been inhibited by prior iodoacetamide incubation. Borage oil and artificial lipid droplets were used as model systems of free and restricted diffusion, respectively. The characteristic diameter for the ML resonance compartment measured by NMR for the C6 cells was not significantly different from the one obtained with phase contrast microscopy (1.88 +/- 0.04 micro m from NMR versus 1.37 +/- 0.33 micro m from microscopy). We herewith provide direct and noninvasive evidence that the lipid signal at 1.26 ppm in C6 cells, which remains visible in long echo time (T(E) = 136 ms) experiments, mostly originates from subcellular structures with diameters of 1-2 micro m, which correspond to the cytosolic lipid droplets that can be detected in optical microscopy preparations of the same cells.

Topics: Animals; Diffusion Magnetic Resonance Imaging; Fatty Acids; gamma-Linolenic Acid; Glioma; Lipid Metabolism; Microscopy, Fluorescence; Nuclear Magnetic Resonance, Biomolecular; Plant Oils; Rats; Subcellular Fractions; Tumor Cells, Cultured

Highly unsaturated fatty acids (HUFAs) are naturally occurring anti-tumour agents. HUFAs act as intracellular signalling molecules in cell proliferation and death. In human glioma, HUFAs may stimulate tumour regression and apoptosis. An implantation glioma model, using the C6 glioma cell line, was used to investigate the bioactivity of locally infused n-6 HUFA gamma linolenic acid (GLA). Rat brains (15 normal and 37 C6 tumour bearing) were infused with vehicle or GLA 200 microM-2 mM. The most active local concentration of GLA for anti-tumour activity was 2 mM, infused at 1 microl/h over 7 days. Tumour regression, increased apoptosis and decreased proliferation were observed in tumours of rats infused with this concentration of GLA. Little effect on normal neuronal tissue was detected. The intraparenchymal route was an effective method of GLA administration in the treatment of glioma. These studies provide further insights into the potential role of HUFAs as anti-glioma agents.

Topics: Animals; Apoptosis; Biological Availability; Brain; Brain Neoplasms; Cell Division; Disease Models, Animal; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Glioma; In Situ Nick-End Labeling; Male; Rats; Rats, Wistar; Signal Transduction

The highly unsaturated fatty acids (HUFA) of the n-6 and n-3 series are involved in cell signalling in normal and transformed cells and have recently been associated with pathways leading to tumour cell death. The antitumour activity of three HUFA (arachidonic acid, gamma linolenic acid and eicosapentaenoic acid) were studied in glioma cells and tissue. Using five glioma models, including primary cell suspensions prepared from 46 human glioma samples and an in vivo rat C6 glioma model, we obtained evidence that, following exposure to HUFA, either administered into the medium surrounding human glioma cells or in 16 preparations of multicellular spheroids derived from human and rodent glioma cell lines (C6, MOG, U87, U373) or administered intra-tumourally by infusion using osmotic mini-pumps in 48 rats, glioma regression and apoptosis were detected. Additionally, synergy between gamma irradiation and HUFA administration was observed in 13 experiments analyzing C6 glioma cell apoptosis in vitro. These pro-apoptotic and antiproliferative activities were observed using both C18 and C20 fatty acids of the n-6 and n-3 series, but not when saturated and monounsaturated C18 and C20 fatty acid preparations were used. In the glioma infusion model, in addition to the apoptosis detected in glioma tissue infused with HUFA for 3-7 days, preservation of normal neural tissue and vasculature in adjacent brain was observed. Also, there was little evidence of acute inflammatory infiltration in regressing tumours. Our findings suggest that intraparenchymal infusion of HUFA may be effective in stimulating glioma regression.

Topics: Animals; Apoptosis; Arachidonic Acid; Brain Neoplasms; Cell Division; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Glioma; Humans; In Situ Nick-End Labeling; Rats; Reactive Oxygen Species; Tumor Cells, Cultured; X-Rays

We hypothesized that the cytotoxic effect of GLA observed in glioma but not normal glial cells reflects differences in GLA metabolism and/or antioxidant enzyme levels between these cells. The PUFA content of unsupplemented glioma cells was approximately 50% of that seen in unsupplemented astrocytes. Supplementation with 20 microM GLA for 24 h led to a 230 and 22% increase in glioma and astrocyte PUFA content, respectively, such that both supplemented cell types contained similar levels of PUFA. No major differences were seen in terms of GLA metabolites retained in the cells or secreted into the media following incubation with [(3)H]-GLA. No significant differences were observed in activity of MnSOD or CuZn-SOD between the cells. However, CAT and GPx activity in the glioma cells was significantly higher and lower, respectively, than observed in normal astrocytes. GLA supplementation resulted in a significant increase in CAT activity in normal astrocytes; glioma CAT activity was unchanged. No significant change was seen in the other antioxidant enzymes following GLA supplementation. These results suggest that the cytotoxic effect of GLA on glioma cells reflects both increased PUFA content and an inability to upregulate CAT.

Topics: Animals; Antioxidants; Astrocytes; Carbon Radioisotopes; Catalase; Culture Media, Conditioned; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Glioma; Glutathione Reductase; Lipid Metabolism; Rats; Superoxide Dismutase; Tumor Cells, Cultured

Reactive oxygen intermediates (ROIs) are important signals controlling cell growth and cell death. Local essential fatty acid (EFA) deficiencies in tumour cells may limit tumour ROI generation. This deficiency may be rectified by the addition of exogenous EFA.. The n-6 EFA effects on tumour ROIs were analysed in terms of kinetics, dose-response and individual cell type responses using flow cytometry of intracellular 2',7'-dichlorofluorescin oxidation. ROI formation in 30 gliomas and five paired samples of normal brain tissue, > 500 000 cells per specimen, was analysed every 10 s for 0-25 min.. Tumour cell basal ROI was lower than normal brain tissue ROI from the same subjects (P < 0.00002). Normal and tumour cell ROIs were stimulated by 4-40 micromol L-1 n-6 EFAs, arachidonic acid (AA) and gamma-linolenic acid (GLA). The stimulated ROI rate was exponential, with the maximum dependent on EFA concentration and tumour grade.. EFAs stimulated tumour cells more than normal cells (P < 0.0000017, n = 71) and increased ROIs in glial fibrillary acidic protein-positive cells in tumours. This indicated high sensitivity of glioma cell ROIs to n-6 EFAs.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Female; gamma-Linolenic Acid; Glial Fibrillary Acidic Protein; Glioma; Humans; Male; Middle Aged; Reactive Oxygen Species

Topics: Animals; Antineoplastic Agents; Astrocytes; Astrocytoma; Cell Survival; Cyclooxygenase Inhibitors; Dinoprost; F2-Isoprostanes; Fatty Acids; gamma-Linolenic Acid; Glioma; Ibuprofen; Lipoxygenase Inhibitors; Oxidative Stress; Radiation Tolerance; Rats; Tumor Cells, Cultured

gamma-Linolenic acid (GLA) has been shown to have selective tumoricidal action both in vitro and in vivo. Earlier, in a limited clinical study, we have demonstrated that intra-tumoral administration of GLA can induce regression of human gliomas. In an extension of this study, we evaluated the effect of intra-cerebral injection of GLA on normal dog brain and in 15 patients with malignant gliomas. Histopathological examination revealed that GLA is not cytotoxic to the normal dog brain cells. Administration of 10 mg of GLA via a cerebral reservoir placed in the tumour bed, at the rate of 1 mg/day over a period of 10 days, revealed that GLA is not only safe and non-toxic but can also regress cerebral gliomas as evaluated by computerised tomography and increased survival of the patients by 1.5-2 years. Based on these results and our earlier in vitro study, we suggest that GLA is a safe anti-tumour agent and recommend its use in the management of human gliomas.

Topics: Adult; Aged; Aged, 80 and over; Animals; Astrocytoma; Brain Neoplasms; Dogs; Female; gamma-Linolenic Acid; Glioblastoma; Glioma; Humans; Injections, Intralesional; Male; Middle Aged; Tomography, X-Ray Computed