Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2N8, Canada.
Biomaterials. 2010 Aug;31(22):5886-93. doi: 10.1016/j.biomaterials.2010.03.075. Epub 2010 Apr 27.
In this study, an engineered non-viral polymer based delivery systems with structural features mimicking that of viral vectors was developed and the potential of this carrier for siRNA delivery was assessed. The developed siRNA carrier was based on poly(ethylene oxide)-block-poly(epsilon-caprolactone) (PEO-b-PCL) micelles decorated with integrin alphavbeta3 targeting peptide (RGD4C) and/or cell penetrating peptide (TAT) on the PEO shell, and modified with a polycation (spermine) in the PCL core for siRNA binding and protection. We observed increased cellular uptake and effective endosomal escape of siRNA delivered with the peptide-functionalized micelles especially those with dual functionality (RGD/TAT-micelles) compared to unmodified micelles (NON-micelles) in MDA435/LCC6 resistant cells. Transfection of mdr1 siRNA formulated in peptide-modified micelles led to P-gp down regulation both at the mRNA and protein level. Subsequent to P-gp down regulation, increased cellular accumulation of P-gp substrate, doxorubicin (DOX), in the cytoplasm and nucleus of resistant MDA435/LCC6 cells after treatment with peptide decorated polymeric micelle/mdr1 siRNA complexes was observed. As a result, resistance to DOX was successfully reversed. Interestingly, RGD/TAT-micellar siRNA complexes produced improved cellular uptake, P-gp silencing, DOX cellular accumulation, DOX nuclear localization and DOX induced cytotoxicity in MDA435/LCC6 cells when compared to micelles decorated with individual peptides. Results of this study indicated a potential for RGD/TAT-functionalized virus-like micelles as promising carriers for efficient delivery of mdr1 siRNA to MDA435/LCC6 resistant cells as means to reverse the P-gp mediated multidrug resistance to DOX.
在这项研究中，开发了一种具有模仿病毒载体结构特征的工程非病毒聚合物基递药系统，并评估了该载体用于 siRNA 递药的潜力。所开发的 siRNA 载体基于聚（乙二醇）-嵌段-聚（己内酯）（PEO-b-PCL）胶束，其 PEO 壳上带有整合素 alphavbeta3 靶向肽（RGD4C）和/或细胞穿透肽（TAT），并且 PCL 核中用聚阳离子（精胺）进行修饰以用于 siRNA 结合和保护。与未修饰的胶束（NON-胶束）相比，我们观察到用肽功能化胶束递呈的 siRNA 具有更高的细胞摄取率和有效的内涵体逃逸，特别是那些具有双重功能（RGD/TAT-胶束）的胶束。在用肽修饰的胶束包封的 mdr1siRNA 转染后，导致 P-gp 在 mRNA 和蛋白水平下调。在 P-gp 下调后，在用肽修饰的聚合物胶束/mdr1siRNA 复合物处理耐药 MDA435/LCC6 细胞后，观察到 P-gp 底物阿霉素（DOX）在细胞质和细胞核中的细胞内积累增加。结果，成功逆转了 DOX 的耐药性。有趣的是，与用单个肽修饰的胶束相比，RGD/TAT-胶束 siRNA 复合物在 MDA435/LCC6 细胞中产生了更好的细胞摄取、P-gp 沉默、DOX 细胞内积累、DOX 核定位和 DOX 诱导的细胞毒性。这项研究的结果表明，RGD/TAT 功能化病毒样胶束作为有效递呈 mdr1siRNA 至 MDA435/LCC6 耐药细胞的有前途的载体具有潜力，可作为逆转 P-gp 介导的多药耐药性至 DOX 的手段。
