13C C16 Sphingomyelin is an isotopically enriched form of C16 sphingomyelin with carbon-13 occurring on the fatty acid portion. It is intended for use as an internal standard for the quantification of C16 sphingomyelin by GC- or LC-MS. C16 Sphingomyelin is a form of sphingomyelin containing palmitate (16:0) at the variable acylation position. It is the most common form of sphingomyelin found in eggs and is less abundant in the brain and in milk. C16 Sphingomyelin interacts with cholesterol in ordered lipid domains (lipid rafts). Sphingomyelinases remove phosphorylcholine from C16 sphingomyelin to produce C16ceramide. While ceramides commonly induce apoptosis, ceramides with different fatty acid chain lengths might direct distinct functions and, in some cases, reduce apoptosis.
C6 urea ceramide is an inhibitor of neutral ceramidase.1 It increases total ceramide levels in wild-type mouse embryonic fibroblasts (MEFs) and in HT-29 colon cancer cells but not in MEFs lacking neutral ceramidase. It inhibits proliferation of, and induces apoptosis and autophagy in HT-29, but not non-cancerous RIE-1, cells when used at concentrations of 5 and 10 μM. C6 urea ceramide decreases total β-catenin, increases phosphorylated β-catenin, and induces colocalization of β-catenin with the 20S proteasome in HT-29 and HCT116, but not RIE-1, cells. It reduces tumor growth and increases C16, C18, C20, and C24 ceramide levels in tumor tissue in an HT-29 mouse xenograft model when administered at doses of 1.25, 2.5, and 5 mg/kg for five days. |1. García-Barros, M., Coant, N., Kawamori, T., et al. Role of neutral ceramidase in colon cancer. FASEB J. 30(12), 4159-4171 (2016).
ARN14988 is a potent inhibitor of acid ceramidase (IC50 = 12.8 nM for the human enzyme). It inhibits acid ceramidase activity and increases levels of C16 dihydro ceramide and C16ceramide in A375, G361, M14, MeWo, MNT-1, and SK-MEL-28 melanoma cells. ARN14988 also reduces growth of A375 and G361 melanoma cells (EC50s = 41.8 and 67.7 μM, respectively).