Department of Bioengineering, Faculty of Engineering, National University of Singapore,7 Engineering Drive 1, Singapore 117574, Singapore.
Biomaterials. 2013 Sep;34(27):6482-94. doi: 10.1016/j.biomaterials.2013.03.071. Epub 2013 Apr 17.
A new redox-sensitive poly(ethylene glycol) (PEG)-based gene vector specially designed to target fibroblast growth factor receptors (FGFRs) was developed by host-guest supramolecular complexation. The new vector was designed as follows: 1) A host segment was consisted of β-cyclodextrin-crosslinked low molecular polyethylenimine (PEI) conjugated with MC11 peptide (MQLPLATGGGC) that can target FGFRs, being termed as MC11-PEI-β-cyclodextrin (MPC); 2) A guest segment is consisted of PEG and adamantyl group linked by a disulfide bond, the adamantyl-SS-PEG (Ad-SS-PEG); and 3) PEGylation of MPC by supramolecular complexation between MPC and Ad-SS-PEG to generate MPC/Ad-SS-PEG polycation, where the PEG chains can stabilize the DNA polyplexes extracellularly but can be readily cleavable intracellularly. It was found that the MPC/Ad-SS-PEG complexes could efficiently condense pDNA into nanoparticles around 100-200 nm, and were able to effectively stabilize polyplexes against salt- or BSA-induced aggregation. The MPC/Ad-SS-PEG polyplexes were more readily to dissociate with the aid of heparin in the presence of 5 mm DTT. In vitro gene transfection and cytotoxicity experiments in different carcinoma cell lines expressing FGFRs showed that MPC/Ad-SS-PEG could mediate significantly higher transfection efficiency than MPC complexed with adamantyl-PEG (MPC/Ad-PEG), which has no disulfide linkage and is non-PEG-detachable. Furthermore, confocal laser scanning microscopy study indicated that MPC/Ad-SS-PEG polyplexes could mediate much more efficient endosomal escape than stably shield MPC/Ad-PEG polyplexes at 12 h post-transfection. Importantly, MPC/Ad-SS-PEG was also able to efficiently mediate tumor-targeted gene delivery in the tumor-bearing mouse model after systemic injection in vivo. These results suggest that the MPC/Ad-SS-PEG systems could be a safe and efficient non-viral vector for FGFR-mediated targeted gene delivery for cancer gene therapy.
一种新的基于氧化还原敏感的聚乙二醇（PEG）的基因载体，专门设计用于靶向成纤维细胞生长因子受体（FGFRs），是通过主客体超分子络合作用开发的。该新载体设计如下：1）主体部分由β-环糊精交联的低分子量聚亚乙基亚胺（PEI）与 MC11 肽（MQLPLATGGGC）偶联而成，可靶向 FGFRs，称为 MC11-PEI-β-环糊精（MPC）；2）客体部分由 PEG 和金刚烷基通过二硫键连接而成，金刚烷-SS-PEG（Ad-SS-PEG）；3）通过 MPC 与 Ad-SS-PEG 之间的超分子络合作用对 MPC 进行 PEG 化，生成 MPC/Ad-SS-PEG 聚阳离子，其中 PEG 链可以在细胞外稳定 DNA 多聚物，但可以在细胞内容易地断裂。研究发现，MPC/Ad-SS-PEG 复合物可以有效地将 pDNA 凝聚成 100-200nm 左右的纳米颗粒，并能够有效地稳定多聚物抵抗盐或 BSA 诱导的聚集。在存在 5mM DTT 的情况下，MPC/Ad-SS-PEG 多聚物在肝素的帮助下更容易解离。在表达 FGFRs 的不同癌细胞系中进行的体外基因转染和细胞毒性实验表明，MPC/Ad-SS-PEG 可以介导比 MPC 与金刚烷-PEG（MPC/Ad-PEG）复合物更高的转染效率，MPC/Ad-PEG 复合物没有二硫键，并且不可 PEG 分离。此外，共聚焦激光扫描显微镜研究表明，MPC/Ad-SS-PEG 多聚物在转染后 12 小时可以介导更有效的内涵体逃逸，而稳定屏蔽的 MPC/Ad-PEG 多聚物则不能。重要的是，MPC/Ad-SS-PEG 还能够在体内全身注射后在荷瘤小鼠模型中有效介导肿瘤靶向基因传递。这些结果表明，MPC/Ad-SS-PEG 系统可能是一种安全有效的非病毒载体，用于 FGFR 介导的靶向基因传递，用于癌症基因治疗。
