Polyunsaturated and monounsaturated fatty acids increase neutral lipid accumulation, caspase activation and apoptosis in a neutrophil-like, differentiated HL-60 cell line.

We report here that monounsaturated fatty acids and polyunsaturated fatty acids (PUFAs) provoke the accumulation of neutral lipids and apoptosis in retinoic acid-treated HL-60 cells in a concentration- and time-dependent manner. The PUFAs (arachidonic acid, docosahexanoic acid and eicosapentaenoic acid) provoked higher levels of HL-60 apoptosis compared with the monounsaturated oleic acid or the saturated palmitic acid. Cell size and granularity were also altered by fatty acid treatment. The PUFA-induced apoptosis was correlated with increased activity of caspase 3 and caspase 9. Lipid peroxidation was also increased in the presence of PUFAs, but was not responsible for activating cell apoptosis. Lipid derived metabolites may be responsible for activation of caspases and induction of cell apoptosis.