Docosahexaenoic acid in phosphatidylcholine mediates cytotoxicity more effectively than other omega-3 and omega-6 fatty acids.

We reported previously that docosahexaenoic acid (22:6)-containing phosphatidylcholine (PC), but not oleic acid-containing PC nor 22:6-containing phosphatidylethanolamine, is toxic to tumor cells in vitro. To test whether other polyunsaturated fatty acids share 22:6's cytotoxic activity, we treated cultured T27A murine leukemia cells with PC liposomes composed of stearic acid in the sn-1 position and alpha-linolenic acid (alpha-18:3), arachidonic acid (20:4), or eicosapentaenoic acid (20:5) in the sn-2 position. PC containing 22:6 in both positions was also tested.