Dowler Thomas, Bergeron Denis, Tedeschi Anna-Lisa, Paquet Luc, Ferrari Nicolay, Damha Masad J
Topigen Pharmaceuticals Inc., 2901 East Rachel Street, Room 13, Montreal, Quebec, Canada H1W 4A4.
Nucleic Acids Res. 2006 Mar 22;34(6):1669-75. doi: 10.1093/nar/gkl033. Print 2006.
RNA interference (RNAi) has emerged recently as an efficient mechanism for specific gene silencing. Short double-stranded small interfering RNAs (siRNAs) are now widely used for cellular or drug target validation; however, their use for silencing clinically relevant genes in a therapeutic setting remains problematic because of their unfavourable metabolic stability and pharmacokinetic properties. To address some of these concerns, we have investigated the properties of siRNA modified with 2'-deoxy-2'-fluoro-beta-d-arabinonucleotide units (araF-N or FANA units). Here we provide evidence that these modified siRNAs are compatible with the intracellular RNAi machinery and can mediate specific degradation of target mRNA. We also show that the incorporation of FANA units into siRNA duplexes increases activity and substantially enhances serum stability of the siRNA. A fully modified sense 2'-deoxy-2'-fluoro-beta-D-arabinonucleic acid (FANA) strand when hybridized to an antisense RNA (i.e. FANA/RNA hybrid) was shown to be 4-fold more potent and had longer half-life in serum (approximately 6 h) compared with an unmodified siRNA (<15 min). While incorporation of FANA units is well tolerated throughout the sense strand of the duplex, modifications can also be included at the 5' or 3' ends of the antisense strand, in striking contrast to other commonly used chemical modifications. Taken together, these results offer preliminary evidence of the therapeutic potential of FANA modified siRNAs.
RNA干扰（RNAi）最近已成为一种有效的特异性基因沉默机制。短双链小干扰RNA（siRNA）现在广泛用于细胞或药物靶点验证；然而，由于其不良的代谢稳定性和药代动力学特性，它们在治疗环境中用于沉默临床相关基因仍然存在问题。为了解决其中一些问题，我们研究了用2'-脱氧-2'-氟-β-D-阿拉伯核苷酸单元（araF-N或FANA单元）修饰的siRNA的特性。在此，我们提供证据表明，这些修饰的siRNA与细胞内RNAi机制兼容，并且可以介导靶mRNA的特异性降解。我们还表明，将FANA单元掺入siRNA双链体中可提高活性并显著增强siRNA的血清稳定性。与未修饰的siRNA（<15分钟）相比，当与反义RNA杂交时（即FANA/RNA杂交体），完全修饰的有义2'-脱氧-2'-氟-β-D-阿拉伯核酸（FANA）链的效力提高了4倍，并且在血清中的半衰期更长（约6小时）。虽然在双链体的有义链中掺入FANA单元具有良好的耐受性，但修饰也可以包含在反义链的5'或3'末端，这与其他常用的化学修饰形成鲜明对比。综上所述，这些结果为FANA修饰的siRNA的治疗潜力提供了初步证据。
