Changes in intracellular concentrations of amino acids and polyamines during the apoptosis of HL-60 cells

Possible changes in the intracellular concentrations of amino acids and pol yamines were investigated during the apoptosis of human promyelocytic leuke mic HL-60 cells. Treatment of HL-60 cells with sodium 5,6-benzylidene-L-asc orbate (SBA) or sodium ascorbate induced apoptotic cell death characterized by chromatin condensation, nuclear fragmentation, loss of microvilli, and production of numerous vacuoles and apoptotic bodies. The apoptosis was acc ompanied by a significant increase in the intracellular concentration of al most all neutral and basic amino acids (regardless of their polarity). On t he other hand, the concentration of glutamic acid, the most abundant amino acid in the cells, was significantly reduced These data suggest the reduced amino acid utilization and possible membrane impairment, especially in SEA -treated cells. Among three major polyamines, the intracellular concentrati on of putrescine rapidly declined, whereas that of spermidine and spermine was almost unchanged during apoptosis. Conversely, the concentration of put rescine, but not that of spermidine and spermine, was significantly increas ed during the chemically-induced carcinogenesis of mouse liver tissue. The present study demonstrates that the putrescine level is the most sensitive to the proliferation capability of the cells among three polyamines, and pr ovides an early marker for apoptosis and proliferation.