Abstract
Ceramide is well known as a regulator of cell apoptosis and cell growth suppression. In this study, we synthesized more lipophilic ceramide derivatives in order to incorporate into lipid microsphere (LM), and their activity was evaluated in vivo. Cera 03, diacetylated form of C2-ceramide showed a potent cell growth inhibition and potently induced apoptosis in both U 937 cells and Meth A-T tumor cells in vitro, with a similar potency as cell membrane-permeable C2-ceramide. Diacetylated form of natural type ceramide (Ger), Cera 02, also suppressed the in vitro cell growth with a similar potency as that of Cer, which was much lower than that of C2-ceramide and Cera 03. LM preparation of Cera 03 (Lipo-Cera 03, 1 mg/ml) was stable, and inhibited the murine experimental pulmonary metastasis employed with Meth A-T cells. Intravenous injection of lipo-Cera 03 (1 mg/kg of Cera 03) showed over 35% inhibition in the experimental metastasis model. In while, LM preparation of Cera 02 (Lipo-Cera 02, 1 mg/ml) was also stable, however, a significant efficacy was not observed. Therefore, LM emulsion of a ceramide derivative (Cera 03) has a potential for an anti-metastatic injectable drug, and also would be an useful tool for researching the role of ceramide in vivo.
