Inhibition of cell growth, induction of apoptosis, and inhibition of FIP1L1-PDGFRα kinase activity in EOL-1 cells treated with various kinase inhibitors. (A) Dose-response curves of EOL-1 cells treated with imatinib, PKC412, or SU5614. The percentage of growth relative to untreated cells is plotted for increasing drug concentrations (48-hour incubation). (B) Detection of apoptotic EOL-1 cells after 24-hour incubation with imatinib (10 nM), PKC412 (100 nM), or SU5614 (100 nM). Apoptotic cells (lower right quadrant), necrotic cells (upper right quadrant), and viable cells (lower left quadrant) were detected. (C) Phosphorylation of FIP1L1-PDGFRα was analyzed using antiphosphotyrosine antibody on immunoprecipitated FIP1L1-PDGFRα. Phosphorylation of STAT5 was analyzed using anti-phospho-STAT5 antibody, which recognizes phosphorylated STAT5a (upper band) and STAT5b (lower band). Membranes were blotted with anti-PDGFRα or anti-STAT5a antibodies as loading control.