Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, 360 Huntington Ave, Boston, MA 02115, USA.
Drug Deliv Transl Res. 2011 Feb 1;1(1):25-33. doi: 10.1007/s13346-010-0004-0.
Gene silencing using small interfering RNA (siRNA) is a promising therapeutic strategy for the treatment of various diseases, in particular, cancer. Recently, our group reported on a novel gene carrier, the micelle-like nanoparticle (MNP), based on the combination of a covalent conjugate of phospholipid and polyethylenimine (PLPEI) with polyethylene glycol (PEG) and lipids. These long-circulating MNPs loaded with plasmid DNA-mediated gene expression in distal tumors after systemic administration in vivo. In the current study, we investigated the potential of MNPs for siRNA delivery. MNPs were prepared by condensing siRNA with PLPEI at a nitrogen/phosphate ratio of 10, where the binding of siRNA is complete. The addition of a PEG/lipid coating to the PLPEI complexes generated particles with sizes of ca. 200 nm and a neutral surface charge compared with positively charged PLPEI polyplexes without the additional coating. MNPs protected the loaded siRNA against enzymatic digestion and enhanced the cellular uptake of the siRNA payload. MNPs carrying green fluorescent protein (GFP)-targeted siRNA effectively downregulated the gene in cells that stably express GFP. Finally, MNPs were non-toxic at a wide range of concentrations and for different cell lines.
利用小干扰 RNA（siRNA）进行基因沉默是治疗各种疾病（尤其是癌症）的一种很有前途的治疗策略。最近，我们小组报道了一种新型基因载体，即胶束样纳米颗粒（MNP），它是基于磷脂和聚乙烯亚胺（PLPEI）与聚乙二醇（PEG）和脂质的共价缀合物。这些长循环 MNPs 在体内全身给药后可将质粒 DNA 介导的基因表达递送到远端肿瘤。在本研究中，我们研究了 MNP 用于 siRNA 递药的潜力。通过将 siRNA 与 PLPEI 在氮/磷比为 10 的条件下缩合来制备 MNP，此时 siRNA 的结合是完全的。在 PLPEI 复合物上添加 PEG/脂质涂层可生成粒径约为 200nm 且表面带中性电荷的颗粒，而不带额外涂层的带正电荷的 PLPEI 超分子复合物则带正电荷。MNP 可保护负载的 siRNA 免受酶消化，并增强 siRNA 有效载荷的细胞摄取。携带靶向绿色荧光蛋白（GFP）的 siRNA 的 MNP 可有效下调稳定表达 GFP 的细胞中的基因。最后，MNP 在广泛的浓度范围内和不同的细胞系中均无毒性。
