title: 2'-O-Lysylaminohexyl oligonucleotides: modifications for antisense and siRNA.
abstract: A novel type of oligonucleotide has been developed, characterized by the attachment of a lysyl moiety to a 2'-O-aminohexyl linker. A protected lysine building block was tethered to 2'-O-aminohexyluridine, and the product was converted into the corresponding phosphoramidite. Up to six modified nucleosides were incorporated in dodecamer DNA and RNA oligonucleotides using standard phosphoramidite chemistry. Each of the building blocks contributes one positive charge to the oligonucleotide instead of the negative charge of a wild-type nucleotide. Thermal denaturation profiles indicated a stabilizing effect of 2'-O-lysylaminohexyl chains that was more pronounced in RNA duplexes. Incubation of the oligonucleotides with 5'-exonuclease revealed an exceptionally high stability against enzymatic degradation. Incorporation of up to three modifications into functional antisense and siRNA oligonucleotides targeted at ICAM-1 showed that the gene-silencing activity was higher with an increasing number of lysylaminohexyl nucleotides. Compared with wild-type antisense or siRNA, compounds with three modifications led to equal or higher ICAM-1 downregulation.
authors.affiliation: Department of Medicinal Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Winkler
authors.forename: Matthias
authors.initials: M
authors.lastname: Gilbert
authors.forename: Aneta
authors.initials: A
authors.lastname: Kocourková
authors.forename: Martina
authors.initials: M
authors.lastname: Stessl
authors.forename: Christian R
authors.initials: CR
authors.lastname: Noe
mesh_terms: D000588:Amines / Q000737:chemistry; D001483:Base Sequence; D002460:Cell Line; D002942:Circular Dichroism; D005090:Exodeoxyribonucleases / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000494:pharmacology*; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000737:chemistry / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects*
chemical_list: D000588:Amines; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D034741:RNA, Small Interfering; D005090:Exodeoxyribonucleases; D008239:Lysine