A potent, selective inhibitor of SPHK 1 with anti-proliferative activity; exhibits non-ATP-competitive inhibition of human recombinant GST-SPHK 1 with an IC50 value of 0.5 µM, with no inhibition against ERK2, PI3K or PKCα at concentrations up to 60 µM; inhibits proliferation of human cancer cell lines (T-24, MCF-7, NCI/ADR, and MCF-7/VP) with IC50 values in the low µM range (0.9-4.6 µM).