Inhibition of angiogenic factor- and tumour-induced angiogenesis by gamma linolenic acid

Angiogenesis, the formation of new blood vessels, is an essential feature o f malignant tumour development. Gamma linolenic acid (GLA), a n-6 polyunsat urated fatty acid (PUFA), inhibits the growth and metastasis of a variety o f tumour cells, including breast, prostate, pancreatic cancer and hepatoma cells and also has anti-metastatic effects on endothelial cells. In the cur rent study, we tested whether GLA inhibited angiogenesis induced by tumour cells. A rat aortic ring assay and in vitro tube formation of human vascula r endothelial cells were used to determine angiogenesis (spontaneous, angio genic factor- and tumour cells-induced). Inclusion of GLA in this 3-D matri x culture system significantly inhibited angiogenesis from aortic rings in a concentration-dependent manner. The results from tube formation of vascul ar endothelial cell further confirmed that GLA suppressed angiogenesis. Fur thermore, in the cell motility assay (phagokinetic assay and endothelial wo unding assay), a significant reduction of the motility of vascular endothel ial cells by GLA was seen. It is concluded that gamma linolenic acid inhibi ts angiogenic factor and tumour-induced angiogenesis in vitro at least in p art via its inhibitory effect on the motility of vascular endothelial cells .