Ceranib1 produces a dose-dependent decrease in ceramidase activity, with 50% inhibition at 55 and 28 μM in SKOV3 cells. Ceranib1 prevents the hydrolysis of endogenous ceramide species and reduces intracellular sphingosine and S1P. Ceranib1 (10 nM-10 μM; 72 hours) exhibits antiproliferative activity for SKOV3 cells. Ceranib1 (24 hours) does not cause significant acute cytotoxicity at concentrations up to at least those used in the ceramidase assay in SKOV3 cells[1].