Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
Future Industries Institute, University of South Australia, Mawson Lakes, Adelaide, SA, 5095, Australia.
J Nanobiotechnology. 2018 Apr 13;16(1):38. doi: 10.1186/s12951-018-0365-y.
Multidrug resistance-associated protein 1 (MRP1) overexpression plays a major role in chemoresistance in glioblastoma multiforme (GBM) contributing to its notorious deadly nature. Although MRP1-siRNA transfection to GBM in vitro has been shown to sensitise the cells to drug, MRP1 silencing in vivo and the phenotypic influence on the tumour and normal tissues upon MRP1 down-regulation have not been established. Here, porous silicon nanoparticles (pSiNPs) that enable high-capacity loading and delivery of siRNA are applied in vitro and in vivo.
We established pSiNPs with polyethyleneimine (PEI) capping that enables high-capacity loading of siRNA (92 µg of siRNA/mg PEI-pSiNPs), and optimised release profile (70% released between 24 and 48 h). These pSiNPs are biocompatible, and demonstrate cellular uptake and effective knockdown of MRP1 expression in GBM by 30%. Also, siRNA delivery was found to significantly reduce GBM proliferation as an associated effect. This effect is likely mediated by the attenuation of MRP1 transmembrane transport, followed by cell cycle arrest. MRP1 silencing in GBM tumour using MRP1-siRNA loaded pSiNPs was demonstrated in mice (82% reduction at the protein level 48 h post-injection), and it also produced antiproliferative effect in GBM by reducing the population of proliferative cells. These results indicate that in vitro observations are translatable in vivo. No histopathological signs of acute damage were observed in other MRP1-expressing organs despite collateral downregulations.
This study proposes the potential of efficient MRP1-siRNA delivery by using PEI-capped pSiNPs in achieving a dual therapeutic role of directly attenuating the growth of GBM while sensitising residual tumour cells to the effects of chemotherapy post-resection.
多药耐药相关蛋白 1（MRP1）过表达在多形性胶质母细胞瘤（GBM）的化疗耐药中起主要作用，导致其致命性。尽管已经证明 MRP1-siRNA 转染体外 GBM 可使细胞对药物敏感，但尚未确定体内 MRP1 沉默以及 MRP1 下调对肿瘤和正常组织的表型影响。在这里，应用多孔硅纳米粒子（pSiNPs）进行体外和体内实验，pSiNPs 能够实现 siRNA 的高容量负载和递送。
我们建立了带聚乙烯亚胺（PEI）帽的 pSiNPs，使其能够实现 siRNA 的高容量负载（92µg siRNA/mg PEI-pSiNPs），并优化了释放曲线（70%在 24-48 小时之间释放）。这些 pSiNPs 具有生物相容性，并在 GBM 中证明了细胞摄取和对 MRP1 表达的有效敲低，可达 30%。此外，siRNA 递呈还发现可显著降低 GBM 的增殖，这是一种相关的作用。这种作用可能是通过减弱 MRP1 的跨膜转运，随后细胞周期停滞来介导的。MRP1 沉默在 GBM 肿瘤中使用负载 MRP1-siRNA 的 pSiNPs 在小鼠中得到证实（注射后 48 小时蛋白水平降低 82%），并通过减少增殖细胞的数量在 GBM 中产生抗增殖作用。这些结果表明，体外观察结果可转化为体内观察结果。尽管存在侧下调，但在其他表达 MRP1 的器官中未观察到急性损伤的组织病理学迹象。
本研究提出了使用带 PEI 帽的 pSiNPs 有效递送 MRP1-siRNA 的潜力，可实现直接减弱 GBM 生长的双重治疗作用，同时使残留肿瘤细胞对切除后化疗的作用敏感。
