Ceramides are bioactive sphingolipids which induce apoptosis in cells.Ceramidases, which hydrolyze the fatty acid chain, keep ceramide levels in check and have been proposed as a target for small-molecule inhibitors for anti-cancer therapy.B13 (or D-NMAPPD) is a potent ceramidase inhibitor which causes aopotosis in a number of cell lines including colorectal, HL60, melanoma, and keratinocyes.