| Autor: |
Guenther DC; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Mori S; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Matsuda S; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Gilbert JA; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Willoughby JLS; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Hyde S; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Bisbe A; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Jiang Y; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Agarwal S; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Madaoui M; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Janas MM; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Charisse K; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Maier MA; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States., Egli M; Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, United States., Manoharan M; Alnylam Pharmaceuticals, 675 West Kendall, Cambridge, Massachusetts 02142, United States. |
| Abstrakt: |
Although 2'-deoxy-2'-α-F-2'-β- C -methyl (2'-F/Me) uridine nucleoside derivatives are a successful class of antiviral drugs, this modification had not been studied in oligonucleotides. Herein, we demonstrate the facile synthesis of 2'-F/Me-modified pyrimidine phosphoramidites and their subsequent incorporation into oligonucleotides. Despite the C3'- endo preorganization of the parent nucleoside, a single incorporation into RNA or DNA resulted in significant thermal destabilization of a duplex due to unfavorable enthalpy, likely resulting from steric effects. When located at the terminus of an oligonucleotide, the 2'-F/Me modification imparted more resistance to degradation than the corresponding 2'-fluoro nucleotides. Small interfering RNAs (siRNAs) modified at certain positions with 2'-F/Me had similar or better silencing activity than the parent siRNAs when delivered via a lipid nanoparticle formulation or as a triantennary N -acetylgalactosamine conjugate in cells and in mice. Modification in the seed region of the antisense strand at position 6 or 7 resulted in an activity equivalent to the parent in mice. Additionally, placement of the antisense strand at position 7 mitigated seed-based off-target effects in cell-based assays. When the 2'-F/Me modification was combined with 5'-vinyl phosphonate, both E and Z isomers had silencing activity comparable to the parent. In combination with other 2'-modifications such as 2'- O -methyl, the Z isomer is detrimental to silencing activity. Presumably, the equivalence of 5'-vinyl phosphonate isomers in the context of 2'-F/Me is driven by the steric and conformational features of the C -methyl-containing sugar ring. These data indicate that 2'-F/Me nucleotides are promising tools for nucleic acid-based therapeutic applications to increase potency, duration, and safety. |
