Oligonucleotides conjugated with short chemically defined polyethylene glycol chains are efficient antisense agents.
Bottom Line: On the other hand, the attachment of long PEG chains negatively influences the pharmacodynamic effect by reducing the hybridization efficiency.Circular dichroism showed that the tethering of PEG12-chains to phosphodiester and phosphorothioate oligonucleotides had no influence on their secondary structure and did not reduce the affinity to the counter strand.In an in vitro tumor model, a luciferase reporter assay indicated unchanged gene silencing activity compared to unmodified compounds, and even slightly superior target down regulation was found after treatment with a phosphorothioate modified conjugate.
Affiliation: University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria.Show MeSH
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Mentions: These linkers were then used as attachment points for NHS-activated PEG12 units (Scheme 1). For a nearly quantitative yield after 2 h reaction time, a 50fold surplus of the NHS-PEG ligand was added from a stock solution in anhydrous DMF to the oligonucleotide dissolved in sodium borate buffer. The unreacted PEG ligand was removed from the mixture by gel filtration, and the PEGylated oligonucleotide was purified by preparative gel electrophoresis. Analyses on gel electrophoresis (Scheme 1) and HPLC confirmed product purities.
Affiliation: University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria.