CAY10621 is an inhibitor of sphingosine kinase 1 (SPHK1; IC50 = 3.3 μM).[1] It is selective for SPHK1 over SPHK2 at 10 μM and PKC at concentrations less than 100 μM. CAY10621 inhibits SPHK1 activity by 70% in U937 cells when used at a concentration of 5 μM.
Reference:
1. Wong, L., Tan, S.L., Lam, Y., et al. Synthesis and evaluation of sphingosine analogues as inhibitors of sphingosine kinases. Journal of Medicinal Chemistry 52, 3618-3626 (2009).