Inhibition of Bcr-abl activity in CML cells augments cellular responses to IFNα. (A) Viability of KT1 cells that received indicated shRNA and were treated with IM (0.5μM for 8 hours), IFNα (250 IU/mL for 8 hours), or a combination (4 hours + 4 hours) of the 2 as indicated. (B) Viability of KU812 cells that received indicated shRNA and were treated as described in panel A. (C) KT1 cells were pretreated with IM (0.5μM) for 8 hours and then treated with IFNα (250 IU/mL) for 30 minutes. Activation and total levels of STAT1 was analyzed in whole cell lysates by immunoblotting using the indicated antibodies. (D) KT1 cells were pretreated with IM (0.5μM) for 8 hours and then treated with IFNα (250 IU/mL) or IFNγ (50 IU/mL) for 30 minutes. Activation and total levels of STAT1 was analyzed in whole cell lysates by immunoblotting using the indicated antibodies.