Suppression of growth in a leukemic T cell line by n-3 and n-6 polyunsaturated fatty acids

Proliferation in a leukemic T cell line (Jurkat) was suppressed in a dose dependent manner by n-6 and n-3 polyunsaturated fatty acids (PUFA) added to the culture medium. At high concentrations, PUFA have a cytotoxic effect on Jurkat cells. The inhibitory effect of the PUFA was not due to production of prostaglandins, and lipid peroxidation was only partly responsible. In addition to production of peroxides and aldehydes, lipid peroxidation also reduced the plasmalogen levels in these cells. The antioxidant alpha-tocopherol blocked lipid peroxidation and restored the plasmalogen levels to normal. alpha-Tocopherol did not totally restore cell proliferation although the MDA-like products in these cultures (supplemented with PUFA) were reduced to control level. Cultures supplemented with n-6 PUFA seemed to respond better to alpha-tocopherol than n-3 PUFA. This suggests that n-6 PUFA may exert their growth inhibitory effect predominantly via lipid peroxidation while different mechanisms might be operating for the n-3 PUFA.