title: Effective incorporation of 2'-O-methyl-oligoribonucleotides into liposomes and enhanced cell association through modification with thiocholesterol.
abstract: Cholesterol was linked to 2'-O-methyl-oligoribonucleotides (2'-OMe-RNA) via a disulfide bond by reacting the 3'-(pyridyldithio)-modified 2'-OMe-RNA with thiocholesterol in dichloromethane-methanol solution. This ligation reaction was made possible by a novel strategy in which the highly charged oligonucleotide was rendered soluble in nonaqueous solvent through conversion to a lipophilic amidinium salt. The biodegradable lipophilic modification of 2'-OMe-RNA resulted in a large increase in incorporation of such oligonucleotides into liposomes prepared by reversephase evaporation. Furthermore, association of these modified oligonucleotides with cultured TIB 73 cells was 100-fold higher than that seen with unmodified 2'-OMe-RNA in serum-free medium and about 10 to 30-fold higher in the presence of 10% calf serum. During incubation with cells, release of the internalized oligonucleotide from the thiocholesteryl moiety can be demonstrated.
authors.affiliation: Institute of Molecular Pathology, Vienna, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Oberhauser
authors.forename: E
authors.initials: E
authors.lastname: Wagner
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000378:metabolism; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides; D008081:Liposomes / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000378:metabolism*
chemical_list: D004220:Disulfides; D008081:Liposomes; D009843:Oligoribonucleotides; C002297:thiocholesterol; D002784:Cholesterol