Selective cytotoxicity of tumor cells induced by liposomes containing plant phosphatidylinositol.

Liposomes containing highly purified phosphatidylinositol (PI) from plant origin selectively killed tumor cells from 8 out of 9 cultured cell lines, but did not kill 4 types of normal cells. Other phospholipids, including PI or phosphatidylserine from animal origin, synthetic phosphatidic acid, phosphatidylglycerol, or phosphatidylcholine, were not cytotoxic. Cholesterol enrichment of cells, shown by other investigators to inhibit tumor development, was slightly cytotoxic in this system, but the toxic effect of cholesterol was minor compared to the massive cytotoxicity induced by plant PI.