Mitochondrial transmembrane potential (ΔΨm) is lost in the early phase of necrosis. (A) BV173 cells were treated with DMSO or imatinib for 3, 6, and 12 hours and treated with zVAD or zVAD + imatinib for 24, 48, and 72 hours. (B) K562 cells were treated with DMSO, imatinib, zVAD, and zVAD + imatinib for 24, 48, and 72 hours. These cells were followed by incubation with DiOC6(3) and PI. ΔΨm and cell death were determined by dual-parameter flow cytometry. Results are representative of 4 individual experiments.