Comparison of antisense oligonucleotides and siRNAs in cell culture and in vivo.

Efficiencies of a nuclease resistant antisense oligonucleotide and of siRNA both being targeted against the green fluorescent protein stably expressed in HeLa cells are compared in cell cultures and in xenografted mice. Using Cytofectin GSV to deliver both inhibitors, the siRNAs appear to be quantitatively more efficient and its effect is lasting for a longer time in cell culture. In mice, we observed an activity of siRNAs but not of antisense oligonucleotides. The absence of efficiency of antisense oligonucleotides is probably due to their lower resistance to nuclease degradation.