SKI-178 is a potent sphingosine kinase-1 (SphK1) and SphK2 inhibitor. SKI-178 is cytotoxic at IC50 concentrations ranging from 1.8 to 0.1 μM in both agent sensitive and multi-agent resistant cancer cell lines (i.e., MTR3, NCI-ADR and HL60/VCR cells). SKI-178 induces apoptosis in a CDK1-dependent manner in human acute myeloid leukemia cell lines.