Cell proliferation assays. (A) 32Dp185 cells were plated in quadruplicate in the presence of regular growth media with or without IL-3 and the indicated amount of inhibitor. Wells were assayed for uptake of MTT at daily intervals. Results are expressed as the mean OD. These assays have been performed four times, all with similar results. (B through D) Cells were plated in the presence of regular growth media with or without IL-3 and the indicated amount of inhibitor. Each day, viable cells were counted as assessed by exclusion of trypan blue. (B) BaF3 cells, (C) BaF3 TEL-ABL cells, (D) BaF3 TEL-PDGFR cells. The data shown are representative of three separate experiments.