磷硫代siRNA的抗肿瘤基因沉默活性研究

由于目前尚无高效合成立体特异性磷硫代siRNAs(PS-siRNAs)的化学体系,本研究针对潜在的癌症治疗靶点PLK1,用a-磷硫代三磷酸腺苷(ATPaS)、a-磷硫代三磷酸胞苷(CTPaS)和a-磷硫代三磷酸尿苷(UTPaS)通过T7RNA聚合酶转录合成了部分磷硫代修饰的Rp-磷硫代siRNAs(Rp-PS-siRNAs),探究了nat-siRNAs和PS-siRNAs血清稳定性和基因沉默活性的差异性。发现酶促合成的磷硫代siRNA几乎不影响siRNA的基因沉默效率,但却显著提高siRNA的血清稳定性。因此,酶促转录合成的Rp-PS-siRNA可望作为siRNA的修饰形式,以延长siRNA的生物活性半衰期,使siRNA广泛应用于生物医学临床研究领域。

Anti-cancer gene silencing of phosphorothioate siRNAs

At present, there is no chemical system for efficient synthesis of stereospecific phosphorothioate siRNAs (PS-siRNAs), this research designed the modified siRNA to target PLK1 for cancer therapy, enzymatically synthesized Rp phosphorothioate siRNAs (Rp-PS-siRNAs) with ATPaS, CTPaS, UTPaS by T7 RNA polymerase, and studied the differences between the nat-siRNAs and PS-siRNAs in serum stability and gene silencing activities. The data showed that the phosphorothioate modification introduced by the enzymatic catalysis could significantly improve the serum stability of siRNA while conserving the siRNA interference efficiency. Therefore, the Rp-PS-siRNA via enzymatic synthesis is of potential properties for developing siRNAs as biomedical research tools with a longer half-life in gene silencing.