Regulation of survivin expression by Bcr-Abl tyrosine kinase in Ph⁺ cells. (A) Survivin expression and viability of KBM5 and KBM5-STI571 cells treated with imatinib. KBM5 and KBM5-STI571 cells were treated with various concentrations of imatinib. Cell viability was determined by trypan blue exclusion and annexin V staining and survivin protein levels by Western blot analysis, both performed 48 hours after treatment. (B-C) Survivin levels by Western blot analysis and cell viability by trypan blue exclusion in 3 accelerated/blastic phase (B) and 4 chronic phase (C) CML samples treated 48 hours ex vivo with various concentrations of imatinib. (D) Survivin expression and viability of HL-60 and HL-60p185 cells treated with 1 μM imatinib for 48 hours. Cell viability was determined by trypan blue exclusion and annexin V staining and survivin protein levels by Western blot analysis.