Cytotoxic effects of free fatty acids on ascites tumor cells.

The effect of physiologic common free fatty acids (FFAs) on Mat 1376b ascites tumor cells in vitro and in vivo in F344 rats was investigated. Unsaturated fatty acids, such as palmitoleic (16:1), oleic (18:1), linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids, were significantly more effective killers of tumor cells in vitro than the corresponding saturated fatty acids of the same carbon length, including palmitic (16:0), stearic (18:0), and arachidic (20:0) acids. The saturated 16-carbon fatty acid (palmitic acid) was more toxic to tumor cells in vitro than the saturated 18-carbon (stearic) and 20-carbon (arachidic) acids. Injections of linoleic (18:2)-linolenic (18:3) acid combinations into rats inoculated with the tumor significantly enhanced the survival of the tumor-bearing animals. These results suggest that natural FFAs may under certain conditions be utilized as effective anticancer agents.