Department of Neurosurgery, Section Experimental Neurosurgery and Tumor Immunology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069, Dresden, Germany.
Small. 2017 Jul;13(27). doi: 10.1002/smll.201700072. Epub 2017 May 22.
Therapeutics based on small interfering RNAs (siRNAs) offer a great potential to treat so far incurable diseases or metastatic cancer. However, the broad application of siRNAs using various nonviral carrier systems is hampered by unspecific toxic side effects, poor pharmacokinetics due to unwanted delivery of siRNA-loaded nanoparticles into nontarget organs, or rapid renal excretion. In order to overcome these obstacles, several targeting strategies using chemically linked antibodies and ligands have emerged. This study reports a new modular polyplex carrier system for targeted delivery of siRNA, which is based on transfection-disabled maltose-modified poly(propyleneimine)-dendrimers (mal-PPI) bioconjugated to single chain fragment variables (scFvs). To achieve targeted delivery into tumor cells expressing the epidermal growth factor receptor variant III (EGFRvIII), monobiotinylated anti-EGFRvIII scFv fused to a Propionibacterium shermanii transcarboxylase-derived biotinylation acceptor (P-BAP) is bioconjugated to mal-PPI through a novel coupling strategy solely based on biotin-neutravidin bridging. In contrast to polyplexes containing an unspecific control scFv-P-BAP, the generated EGFRvIII-specific polyplexes are able to exclusively deliver siRNA to tumor cells and tumors by receptor-mediated endocytosis. These results suggest that receptor-mediated uptake of otherwise noninternalized mal-PPI-based polyplexes is a promising avenue to improve siRNA therapy of cancer, and introduce a novel strategy for modular bioconjugation of protein ligands to nanoparticles.
基于小干扰 RNA（siRNA）的治疗方法为治疗迄今为止无法治愈的疾病或转移性癌症提供了巨大的潜力。然而，由于非特异性毒性副作用、由于将载有 siRNA 的纳米颗粒意外递送到非靶器官而导致的不良药代动力学特性，或由于快速肾排泄，各种非病毒载体系统广泛应用 siRNA 受到阻碍。为了克服这些障碍，已经出现了几种使用化学连接的抗体和配体的靶向策略。本研究报告了一种新的模块化多聚物载体系统，用于靶向递送 siRNA，该系统基于转染失活的麦芽糖修饰的聚（丙烯亚胺）-树枝状大分子（mal-PPI）与单链片段变量（scFv）的生物共轭物。为了实现对表达表皮生长因子受体变体 III（EGFRvIII）的肿瘤细胞的靶向递送，将与丙型丙酸杆菌转羧酶衍生的生物素化接受体（P-BAP）融合的单生物素化抗 EGFRvIII scFv 生物共轭到 mal-PPI 上，通过一种仅基于生物素-亲和素桥接的新型偶联策略。与含有非特异性对照 scFv-P-BAP 的多聚物相比，生成的 EGFRvIII 特异性多聚物能够通过受体介导的内吞作用将 siRNA 专门递送到肿瘤细胞和肿瘤中。这些结果表明，否则未被内化的基于 mal-PPI 的多聚物的受体介导摄取是改善癌症 siRNA 治疗的一种很有前途的途径，并为将蛋白质配体模块化生物共轭到纳米颗粒中引入了一种新策略。
