LY294002 (PI3-K Inhibitor) is a selective, cell permeable, potent and specific inhibitor of phosphatidylinositol 3-kinase (IC50 = 1.4 µM, purified PI 3-kinase). It does not significantly inhibit PKC, PKA, MAP kinase, S6 kinase, EGFrK, c-src kinase, PI 4-kinase, DAG kinase or rabbit kidney ATPase at concentrations of 50 µM. Induces apoptosis. In intact neutrophils stimulated with fMet-Leu-Phe, LY294002 completely abolished PI 3-kinase activity at 50 µM without cell toxicity.