2'-O-Lysylaminohexyl oligonucleotides: modifications for antisense and siRNA

ChemMedChem. 2008 Jan;3(1):102-10. doi: 10.1002/cmdc.200700169.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / chemistry
  • Base Sequence
  • Cell Line
  • Circular Dichroism
  • Exodeoxyribonucleases / metabolism
  • Humans
  • Lysine / chemistry
  • Nucleic Acid Conformation
  • Oligonucleotides / chemical synthesis
  • Oligonucleotides / pharmacology*
  • Oligonucleotides, Antisense / chemistry
  • Oligonucleotides, Antisense / pharmacology*
  • RNA, Small Interfering / chemistry
  • RNA, Small Interfering / pharmacology*
  • Umbilical Veins / cytology
  • Umbilical Veins / drug effects*


  • Amines
  • Oligonucleotides
  • Oligonucleotides, Antisense
  • RNA, Small Interfering
  • Exodeoxyribonucleases
  • Lysine