XXXX -conjugated 21-nucleotide siRNA enhances gene-silencing activity.

@entity1 @entity7 @entity1014 @entity17369 @entity7609
Short interfering RNA (siRNA) technology is a powerful tool for suppressing gene expression in @entity1 cells. In this study, we focused on the development of siRNAs conjugated with @entity7609 at the 5'-end of the sense strand (C16-siRNAs) using our novel synthesis strategy in order to improve the potency of siRNA. The C16-siRNAs exhibited enhanced nuclease stability. In addition, they showed potent gene-silencing efficacy against exogenous Renilla luciferase in HeLa cells compared with a nonmodified siRNA in the presence of Lipofectamine 2000. The C16-siRNAs also had a more potent inhibitory effect on Renilla luciferase activity than the other siRNA conjugated with lipids at the 5'-end and the 3'-end by @entity17369 conjugation. For further improvement, the gene silencing potency of the C16-siRNAs against the endogenous @entity7 ( @entity7 ) gene in HeLa cells was investigated. In this investigation, the siRNAs were prepared not only with the normal RNA sequence but also coupled with an inverted @entity1014 (idT) at the 3'-ends of both the sense and antisense strands (siRNA-idT), including @entity7609 conjugations at the 5'-end of the sense strand, to improve stability. The C16-siRNA including idT modifications exhibited a significantly greater inhibitory effect on the @entity7 gene in the presence of Lipofectamine 2000. It is noteworthy that C16-siRNA-idT demonstrated long-term gene-silencing efficacy of up to 5 days. Interestingly, the C16-siRNAs, including that with idT modifications, exhibited strong RNAi potency in the absence of any transfection reagents, although only at high concentrations. Both the C16-siRNAs and C16-siRNA-idT induced a high level of membrane permeability in HeLa cells. Our developed C16-siRNAs, particularly C16-siRNA-idT, are thus among the promising candidates for a new generation of modified siRNAs that can solve the many problems associated with siRNA technology.
