title: Induction of murine macrophage tumoricidal activity and treatment of experimental pulmonary metastases by liposomes containing lipophilic muramyl dipeptide analogs.
abstract: The ability of three members of a new class of lipophilic muramyl dipeptide derivative to induce murine macrophage tumoricidal activity after liposomal incorporation was investigated. Liposomes containing the glycerol dipalmitate (GDP) derivatives of N-acetylmuramyl-L-alanyl-D-isoglutamine, N-acetylmuramyl-L-alanyl-D-glutamine-n-butyl ester, and N-acetylmuramyl-D-alanyl-D-isoglutamine were 5000, 2000, and greater than 10,000-fold more potent than the free muramyl dipeptides in inducing peritoneal macrophage tumoricidal activity in vitro. In situ activation of peritoneal macrophage tumoricidal activity showed that liposomal muramyl dipeptide-GDP derivatives were more potent than free hydrosoluble or sonicated muramyl dipeptide-GDP preparations. In situ induction of alveolar macrophage tumoricidal activity after i.v. treatment was observed with liposomes containing muramyl dipeptide-GDP derivatives, but not with hydrosoluble or sonicated lipophilic derivatives. Liposomes containing muramyl dipeptide-GDP derivatives were therapeutically active against experimentally induced pulmonary B16 melanoma tumors in C57BL/6 mice. These results demonstrate that when incorporated within liposomes this class of lipophilic muramyl dipeptide derivative is a potent inducer of macrophage tumoricidal activity both in vitro and in situ, and possesses antitumor activity in therapeutic treatment protocols.
authors.affiliation: Montreal General Hospital Research Institute, Quebec, Canada.
authors.forename: N C
authors.initials: NC
authors.lastname: Phillips
authors.forename: L
authors.initials: L
authors.lastname: Chedid
authors.forename: J M
authors.initials: JM
authors.lastname: Bernard
authors.forename: M
authors.initials: M
authors.lastname: Level
authors.forename: P
authors.initials: P
authors.lastname: Lefrancier
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D008081:Liposomes / Q000008:administration & dosage; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000556:secondary; D008262:Macrophage Activation / Q000187:drug effects*; D008297:Male; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000276:immunology / Q000556:secondary; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D008081:Liposomes; D000119:Acetylmuramyl-Alanyl-Isoglutamine