Response of Bcr-Abl–positive CML cells to treatment duration with various concentrations of nilotinib. LAMA-84 (A), KYO-1 (B), and K562 (C) cells were treated with 0, 100, 500, 1000, or 5000 nM nilotinib for the duration indicated, followed by washout, and monitored at 72 hours for annexin V staining. Averages ± SEM are reported for multiple independent experiments (LAMA-84, n = 3; KYO-1, n = 2; K562, n = 2). (D-F) Bcr-Abl activity was monitored with an antibody to phosphorylated CrkL (pY207) after treatment of LAMA-84 (D), KYO-1 (E), and K562 (F) cells with 0, 100, 500, 1000, or 5000 nM nilotinib for the duration indicated and for 4 hours after inhibitor washout. Total CrkL was examined in parallel as a total protein control. Experiments were performed at least twice for each cell line, and a representative dataset is shown.