Effects of Three Protein Phosphatase Inhibitor on A(23187)-induced Apoptosis of HL-60 Cells.
Calcium ionophore A(23187) could increase the intracellular free Ca(2+) concentration and induce apoptosis in some cell lines. In this paper, we reported that A(23187) (1 &mgr;g/ml) could induce apoptosis of HL-60 cells after treating for 4 hours. Pretreatment with the nontoxic concentration of CsA (0.5 3 &mgr;g/ml), an inhibitor of the protein phosphatase 2B (PP2B), could prevent apoptosis induced by A(23187). Neither okadaic acid (OA, inhibitor of PP1, PP2A, PP2C), nor sodium orthovanadate (SoV, inhibitor of tyrosine phosphatase), had such effect. The determination of intracellular Ca(2+) with flow cytometry showed that CsA did not prevent the increase of intracellular Ca(2+) induced by A(23187), which showed that CsA might affect the event in the downstream of calcium increase.
Huang
Qi-Qing
QQ
Department of Biology, Beijing Normal University, Beijing 100875, China.
Zhang
Hong-Qing
HQ
Xue
Shao-Bai
SB