gamma-linolenic-acid and Hypoxia

The main therapies for cancer often results in many side effects and drug resistance. Gamma linolenic acid (GLA) is a kind of natural reagent with negligible cytotoxicity.. This work aims at detecting whether GLA possesses anti-cancer activity in NSCLC cells and elucidating the potential molecular mechanism.. Cytotoxicity of GLA was evaluated by MTT assay and soft agar colony formation method. Immunoblotting analysis examined the effect of GLA on protein expressions of cell proliferation markers (e.g., PCNA, Ki-67 and MCM2), pro-survival protein bcl-2, apoptosis-associated proteins (e.g., bax and cleaved caspase 3), HIF1α and VEGF. Wound healing assay and transwell invasion assay were performed to test the effect of GLA on hypoxia-induced cell migration and invasion. Cell transfection was used to overexpress HIF1α followed by the treatment of GLA to test the effect of HIF1α overexpression on the tumoricidal activity of GLA in NSCLC cell lines.. MTT and soft agar colony formation tests showed that GLA dose-dependently suppressed cell proliferation in both Calu-1 and SK-MES-1 cell lines. Immunoblotting analysis demonstrated that GLA suppressed protein expressions of PCNA, Ki-67, MCM2 and bcl-2, while GLA induced bax and cleaved caspase 3 expressions. Wound healing assay and transwell invasion assay revealed that GLA was very effective on the inhibition of NSCLC cell migration and invasion. Immunoblotting analysis and cell transfection method indicated that GLA inhibited hypoxia-induced cell proliferation and invasion by suppressing HIF1α-VEGF pathway.. GLA suppresses hypoxia-induced proliferation and invasion of NSCLC cells by inhibition of HIF1α pathway in vitro.

Topics: Antineoplastic Agents; bcl-2-Associated X Protein; Carcinoma, Non-Small-Cell Lung; Caspase 3; Cell Line, Tumor; Cell Movement; Cell Proliferation; gamma-Linolenic Acid; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Ki-67 Antigen; Lung Neoplasms; Minichromosome Maintenance Complex Component 2; Neoplasm Invasiveness; Proliferating Cell Nuclear Antigen; Proto-Oncogene Proteins c-bcl-2; Vascular Endothelial Growth Factors

Rats were fed for 6 weeks with a 40% galactose diet to chronically stimulate the polyol pathway. Sciatic motor and saphenous sensory nerve conduction velocity deficits of 22% and 14% respectively developed. Treatment with evening primrose oil or doxazosin from galactosaemia induction partially (approximately 60%) prevented the development of reduced motor and sensory conduction, the former treatment being more successful than the latter. Sciatic nerve resistance to hypoxic conduction failure was 49% increased by galactosaemia. This abnormality was 27% and 43% prevented by doxazosin and evening primrose oil respectively. Galactosaemic sciatic nerves had a 10% increase in water content and endoneurial capillary density was 24% reduced. While neither treatment affected water content, both caused angiogenesis, elevating capillary density by approximately 16%. The data support the hypothesis that, as in experimental diabetes mellitus, the main effect of polyol pathway activation on peripheral nerve function occurs indirectly via a neurovascular action.

Topics: Animals; Body Weight; Doxazosin; Fatty Acids, Essential; Galactose; gamma-Linolenic Acid; Hypolipidemic Agents; Hypoxia; Linoleic Acids; Male; Neural Conduction; Oenothera biennis; Plant Oils; Rats; Rats, Sprague-Dawley; Sciatic Nerve

Essential fatty acid metabolism is impaired by diabetes mellitus and this may be important in the aetiology of peripheral nerve dysfunction. The effects of gamma-linolenic acid (omega-6) and fish oil (omega-3) alone, and in combination, on nerve function and capillarization were examined in 2-month streptozotocin-diabetic rats. Diabetes resulted in approximately 15% and 23% decreases in saphenous sensory and sciatic motor nerve conduction velocities, respectively (p < 0.001). Motor and sensory conduction velocities were in the non-diabetic range after both preventive and reversal omega-6 treatment of diabetic rats (p < 0.001). No significant changes occurred in omega-6 treated non-diabetic rats. Preventive omega-3 treatment was largely ineffective. Reversal treatment with a combination of omega-6 and omega-3 fatty acids was marginally effective and improved motor (p < 0.05), but not sensory conduction velocity. In vitro measurement of sciatic nerve resistance to hypoxic conduction failure in diabetic rats revealed a 56% increase in the time taken for the compound action potential amplitude to be reduced by 80% (p < 0.01) compared to non-diabetic rats. This was partially prevented by omega-6 treatment (29% increase, p < 0.01). Reversal omega-6 treatment had a lesser effect (37% increase, p < 0.05 compared to untreated diabetic rats). omega-3 treatment had no significant effect on conduction failure time. Sciatic endoneurial capillary density increased by 11% with preventive omega-6 treatment (p < 0.05), but was unaffected by reversal omega-6 and by omega-3 treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Capillaries; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Fatty Acids, Omega-3; Fish Oils; gamma-Linolenic Acid; Hypoxia; Male; Motor Neurons; Muscle, Smooth, Vascular; Neural Conduction; Neurons, Afferent; Peripheral Nerves; Rats; Rats, Sprague-Dawley; Reference Values; Sciatic Nerve; Time Factors

1. The aims of this study were first, to examine whether deficits in nerve conduction in streptozotocin-diabetic rats could be reversed by a 10% dietary supplement of evening primrose oil. Second, to determine the time-course of reversal, and third, to assess whether the effects could be blocked by the cyclo-oxygenase inhibitor flurbiprofen (5 mg kg-1 day-1). 2. One-month diabetes produced 20% and 15% deficits in sciatic motor and saphenous sensory conduction velocity respectively, which were maintained over 2 months diabetes. 3. The effect of 1-month evening primrose oil treatment on abnormalities caused by an initial month of untreated diabetes was examined. Motor and sensory nerve conduction velocity were restored to the non-diabetic level. 4. Resistance to hypoxic conduction failure was investigated for sciatic nerve trunk in vitro. The 80% conduction failure times were 29% and 55% prolonged by 1- and 2-month diabetes respectively. Evening primrose oil did not reverse the increased hypoxic resistance following 1-month untreated diabetes. 5. Sciatic nerve endoneurial capillary density was not significantly affected by diabetes, but was 16% increased in diabetic rats with reversal by evening primrose oil treatment for 1 month compared to 2-month untreated diabetes. 6. Serial motor conduction velocity measurement after 3-month untreated diabetes revealed complete normalization by evening primrose oil within 4 days. Cessation of treatment resulted in a rapid decline in conduction velocity over 24 h. 7. In a preventive study of 2-month duration, 6 groups of rats were used. These comprised non-diabetic controls, diabetic rats, and evening primrose oil-treated diabetic rats, both with and without flurbiprofen treatment. Flurbiprofen had no significant effect in non-diabetic rats, but produced an 11% worsening of motor conduction velocity and a 21% reduction of sciatic capillary density in diabetic rats. Evening primrose oil prevented the decreases in conduction velocity and increased hypoxic resistance with diabetes, and caused a 23% increase in capillary density. Flurbiprofen completely blocked the effect of evening primrose oil on conduction velocity, resistance to hypoxia, and capillarization.8. Six main conclusions were reached. First, evening primrose oil rapidly reverses conduction deficits in diabetic rats. Second, the effects of treatment may be very short-lived, suggesting a primary metabolic action. Third, evening primrose oil cannot reverse establ

Topics: Action Potentials; Animals; Body Weight; Capillaries; Cyclooxygenase Inhibitors; Diabetes Mellitus, Experimental; Fatty Acids, Essential; Flurbiprofen; gamma-Linolenic Acid; Hypoxia; Linoleic Acids; Male; Motor Neurons; Neural Conduction; Neurons; Neurons, Afferent; Oenothera biennis; Peroneal Nerve; Plant Oils; Prostaglandins; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Sciatic Nerve