Remarkably high inhibitory effects of docosahexaenoic acid incorporated into hybrid liposomes on the growth of tumor cells along with apoptosis

Inhibitory effects of hybrid liposomes composed of l-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene (20) sorbitan monooleate (Tween 80) including polyunsaturated fatty acids or their ethyl esters (HL-PUFA) on the growth of human tumor cells were examined in vitro. Remarkably high inhibitory effects of HL including docosahexaenoic acid (HL-DHA) and α-linolenic acid ethyl ester (HL-ALAE) on the growth of lung carcinoma (RERF-LC-OK and A549) cells, colon tumor (WiDr) cells and stomach tumor (MKN45) cells were obtained. The addition of vitamin E (α-tocopherol) to HL-DHA and -ALAE prevented almost completely the growth inhibition of A549 cells distinct from the other tumor cells used in this study. On the other hand, fluorescence microscopic and flow cytometric analyses indicated that the inhibitory effects of HL-DHA on the growth of RERF-LC-OK, WiDr and MKN45 cells could be attained through the induction of apoptosis.