CONCENTRATION-DEPENDENT EFFECT OF IRON ON GAMMA-LINOLENIC ACID TOXICITY IN ZR-75-1 HUMAN BREAST-TUMOR CELLS IN CULTURE

Polyunsaturated fatty acids are cytotoxic to ZR-75-1 human breast tumo r cells in culture. This effect may be potentiated by the simultaneous addition of iron. When cytotoxicity was measured in the presence of d ifferent concentrations of both gamma-linolenic acid and ferrous chlor ide there was an increase in cell death above concentrations of 9 muM and 0.05 muM, respectively. The potentiation of the effects of 18:3n-6 at low concentrations by the simultaneous addition of Fe(II) ions sup ports the contention that an alteration in the intracellular Fe(II)/Fe (III) ratio is necessary to promote autocatalytic lipid peroxidation.