Gamma linolenic acid suppresses hypoxia-induced proliferation and invasion of non-small cell lung cancer cells by inhibition of HIF1α

Background 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. Objective This work aims at detecting whether GLA possesses anti-cancer activity in NSCLC cells and elucidating the potential molecular mechanism. Methods 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), HIF1 alpha 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 HIF1 alpha followed by the treatment of GLA to test the effect of HIF1 alpha overexpression on the tumoricidal activity of GLA in NSCLC cell lines. Results 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 HIF1 alpha-VEGF pathway. Conclusion GLA suppresses hypoxia-induced proliferation and invasion of NSCLC cells by inhibition of HIF1 alpha pathway in vitro.