Dose-response curves.

Dose-response curves for STI571 in combination with (A) recombinant IFN-α (r-α-IFN), (B) hydroxyurea (HU), (C) methotrexate (MTX), and (D) vincristine (VCR) in KU812 cells. Cell growth was measured using the MTT assay after 5 days and was plotted as a percentage of the control (cells not exposed to drugs). The concentrations of STI571 were 0 (○), 10 (●), 20 (▪), 30 (▴), 40 (▾), 50 (♦), 60 (▸), 80 (◂) and 100 (x) nM. The concentrations of the combined drugs are shown on the abscissa. Each point represents the mean value for at least 3 independent experiments; the SEMs were less than 20% and were omitted.