Amino acid utilization during apoptosis in HL-60 cells

Human promyelocytic leukemia (HL-60), human squamous carcinoma (HSC-2, HSC- 4, NA) and rat pheochromocytoma (PC-12) cell lines consumed nonpolar (Leu, Ile, Val, Cys, Met, Phe), neutral polar (Gln, Ser, Thr, Tyr) and basic pola r amino acids (Arg, Lys, His), whereas they produced nonpolar (Gly, Pro, Al a) and acidic polar amino acids (Glu). The consumption rate of Ser and Arg by HL-60 cells was significantly higher than that of other cell lines. Duri ng apoptosis of HL-60 cells induced by either sodium ascorbate, sodium 5,6- benzylidene-L-ascorbate (SBA) or dopamine, the consumption on nonpolar and polar amino acids (neutral or acidic) generally declined, except for Cys, M et and Arg, whereas the production of Gly and Glu was slightly increased. S ince the intracellular concentration of cGMP was not significantly changed before and after ascorbate treatment nitric oxide might not be involved in the ascorbate-induced apoptosis. The present data demonstrates that consump tion rate on nonpolar and polar amino acid, whether neutral, acidic or basi c, was reduced almost evenly during the apoptosis induction. This suggests that apoptosis-associated changes in the amino acid utilization might not b e significantly affected by ATP depletion, which might be caused by mitocho ndrial dysfunction.