METABOLIC-FATE AND EFFECTS OF SATURATED AND UNSATURATED FATTY-ACIDS IN HEP2 HUMAN LARYNX TUMOR-CELLS

Previous studies have reported the presence of carnitine palmitoyltran sferase I and II in tumor cells and the inhibitory effects of fatty ac ids on cell proliferation, The present work considered the metabolic f ate of [C-14] or [H-3]-labeled fatty acids and their effects on cellul ar metabolism in Hep2 human larynx tumor cells,The rate of uptake of a cetate was 45% of that of myristate, palmitate, oleate, linoleate and arachidonate, However, acetate was rapidly metabolized within the cell as seen by its low rate of accumulation as non-esterified fatty acid, <5% of that of the other fatty acids, The incorporation of fatty acid s into neutral lipid fractions showed palmitate and oleate primarily e ntered the phospholipid fraction, while linoleate and arachidonate ent ered equally the phospholipid and triacylglycerol fractions. Palmitate and oleate were oxidized to (CO2)-C-14 at higher rates than linoleate and arachidonate, with arachidonate being the least oxidized of the u nsaturated fatty acids. Acetate was oxidized at 10-30 fold higher rate s than the other fatty acids, Palmitate, oleate, linoleate and arachid onate all had significant inhibitory effects on the rate of glucose ut ilization by Hep2 cells, ranging from 25-38% inhibition and were found to inhibit cell proliferation by 17-73%, These findings suggest that certain fatty acids not only play a structural role in cellular metabo lism, but may also have a potential regulatory role in the glycolytic pathway of Hep2 cells.