作者:Johannes Winkler、Benedikt Giessrigl、Clemens Novak、Ernst Urban、Christian R. Noe
DOI:10.1007/s00706-010-0318-0
日期:2010.7
Development of therapeutically active oligonucleotides for sequence-specific gene knockdown relies on chemical modifications that confer high stability and target affinity and ideally enable cellular uptake. 2'-O-Lysylaminohexyluridine-containing antisense and siRNA oligonucleotides have been shown to be well suited for gene knockdown. They are highly resistant to enzymatic degradation while having good affinity for the targeted RNA strand and efficiently down-regulate their target in cell culture tumor models. The 2'-O-lysylaminohexyl modification was expanded to adenosine nucleosides. The corresponding phosphoramidite building block was prepared in a straightforward procedure comprising six steps starting from adenosine. After 2'-O-alkylation with N-(6-bromohexyl)phthalimide and removal of the N-protecting group, the protected lysine was specifically attached to the alkylamino group. Incorporation of 2'-O-lysylaminohexyladenosine nucleotides in a test sequence confirmed that the cationic chains lead only to minor duplex destabilization and do not disturb the duplex structure. Results further emphasize the advantageous properties of 2'-O-lysylaminohexyl modified oligonucleotides for therapeutic applications.