Effects of dietary fatty acids and vitamin E levels in HL-60 cell proliferation

Fatty acids have shown to be both modulators and messengers of signals triggered at the level of cell membranes. There is, however, controversy about the role of fatty acids in cell proliferation kinetics, and it is still unknown whether cell proliferation can be regulated by fatty acid dietary intake in humans. Our objective was to investigate whether feasible changes in the human dietary food intake that induce significant changes in lipids, fatty acids and the oxidative state were able to influence proliferation kinetics of the leukaemia cell line HL-60.

Healthy men and women were subjected to four consecutive dietary periods with increasing degree of unsaturation: saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), n-6 polyunsaturated fatty acids (n-6 PUFAs), n-3 polyunsaturated fatty acids (n-3 PUFAs). Plasma lipids and oxidation parameters were controlled during each period. Serum from each subject in the four dietary periods was incubated for 3 days with the leukaemia cell line, HL-60 (250 x 10(3) cell mL-1), to study cell proliferation.

In men, an n-3 polyunsaturated fatty acid-enriched diet showed a significant inhibition of DNA duplication with respect to a saturated-enriched diet, but the effect is not sufficient in blocking cell proliferation. However, as expected, the in vitro addition of fatty acids to HL-60 cells significantly halted proliferation. In addition, the HL-60 growth ratio was shown to be inversely correlated with plasma vitamin E (P = 0.0004) and oleic acid in phospholipids (P = 0.01) in plasma of the individuals in the dietary intervention study.

Our results demonstrate that changes in serum fatty acid composition obtained with dietary changes, without extreme variations of the regular diets of a free-living population, cannot block HL-60 cell proliferation.