The effect of essential fatty acids on growth and urokinase-type plasminogen activator production in human prostate DU-145 cells

Urokinase-type plasminogen activator (uPA) is an important protease enzyme in carcinogenesis, and is involved in both invasion and metastasis of cancer. Increased uPA activity and decreased essential fatty acid (EFA) levels have been reported in cancer. This phenomenon may be explained by the fact that certain EFAs, such as gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA), inhibit uPA activity. The effect of EFA on human prostate DU-145 cell growth and uPA production is still unknown and was investigated in this study. Data obtained from the different unsaturated fatty acids showed that oleic acid (OA) and EPA enhanced DU-145 cell proliferation at 0.004 and 0.04 mM for up to 4 days. However, alpha-linolenic acid (ALA), linoleic acid (LA), GLA and arachidonic acid (AA) suppressed cell proliferation under the same conditions, possibly as a result of inhibition of DNA and protein synthesis as measured using labelled thymidine and glycine incorporation. In contrast to the cell proliferation, uPA production was inhibited by all the unsaturated fatty acids under investigation. Therefore, the absence of EFAs, as reported, may affect invasion and metastasis of cancer.