Selective non-lipid inhibitor of sphingosine kinase (IC50 = 0.5 μM); does not act at ATP-binding site. Displays no inhibition of ERK2, PI 3-kinase, or PKCα at concentrations up to 60 μM. Reduces levels of sphingosine-1-phosphate in MDA-MB-231 breast cancer cells. Induces apoptosis and inhibits proliferation in several other tumor cell lines in vitro (IC50 = 0.9 - 4.6 μM). Purity 98%. MW (observed): 302.78