S-trityl-L-cysteine derivative induces caspase-independent cell death in K562 human chronic myeloid leukemia cell line

Effect of CF3-STLC, a potent kinesin spindle protein (KSP) inhibitor, on K562 human CML cell line was investigated. Treatment with CF3-STLC induced mitotic arrest of the cell cycle with the appearance of characteristic monoastral spindles, subsequent apoptotic cell death and cleavage of PARP-1, caspase-3, and 4E-BP1. The wide ranging caspase inhibitor z-VAD fmk prevented the cleavage of caspase-3 and 4E-BP1, but failed to attenuate PARP-1 cleavage or cell death triggered by CF3-STLC. These results suggest that CF3-STLC can induce apoptotic cell death in a caspase-independent manner, and may work effectively as an anti-cancer agent for hematological malignancies.