Programmed dual targeted lipopolymeric delivery systems for cancer gene therapy

基因治疗策略需要高效和安全的载体系统。合成递送系统已经被开发出来以规避病毒载体的缺点。基于我们现有合作（自2008年以来）最令人鼓舞的结果，我们将开发脂质体载体，这种载体受到天然病毒靶向特性的启发，并分别利用聚合载体和脂质体载体在DNA压实和内体逃逸方面的优势。对于肿瘤靶向递送，使用全长蛋白或抗体结合肿瘤细胞或肿瘤血管中过表达的细胞表面受体。为了克服蛋白质的复杂性，目前的设计将侧重于合成短肽或化学配体。许多天然病毒的有效细胞摄取是基于在靶细胞上使用一种以上的受体类型。受病毒的启发，在我们之前的联合努力中（聂J.控释2011），我们开发了一种靶向两种不同受体（转铁蛋白受体和α v β 5整合素）的基因递送策略，该策略含有PEG-PEI多聚体的双肽配体。我们现在将研究扩展到具有更好的细胞内递送特性的配体和载体的新组合。在我们的合作中，设计了具有可屏蔽聚乙二醇化的程序化脂多聚物（聂生物材料2011）。这种细胞内更有效的平台现在将与双配体靶向策略合并。脂多聚体与含有靶向肽-PEG-胆固醇的脂质体（带或不带可切割的PEG连接物）物理结合产生。另外，化学共轭脂聚合物将成为靶向脂多聚物的基础。已建立的（RGD, B6）和新的（如GE11，叶酸，TAT）配体将在脂质复合物中进行评估。本研究将探索双靶向配体组合在不同癌症类型（除前列腺癌外，如神经母细胞癌、肝细胞癌）中的机制，特别是对细胞关联和细胞内摄取动力学以及总体转染活性的影响。将比较稳定或pH/还原性脱屏蔽聚乙二醇化。

Gene therapeutic strategies require efficient and safe vector systems. Synthetic delivery systems have been developed to circumvent drawbacks of viral vectors. Based on our most encouraging results of our existing collaboration (since 2008), we will develop lipopolyplex carriers which are inspired by targeting characteristics of natural viruses and take advantage from both polymeric and liposomal carriers, in DNA compaction and endosomal escape, respectively. For tumor targeted delivery, full length proteins or antibodies were used binding cell surface receptors that are overexpressed in tumor cells or tumor vessels. In order to overcome the complexities of proteins, the current design will focus on synthetic short peptide or chemical ligands. Efficient cellular uptake of many natural viruses is based on the utilization of more than one receptor type on target cells. Inspired by viruses, in our previous joint efforts (Nie J. Controlled Release 2011) we developed a gene delivery strategy targeting two different receptors (transferrin receptor and alpha v beta 5 integrin) on prostate cancer cells with dual peptide-ligand containing PEG-PEI polyplexes. We now extend the studies to new combinations of ligands and carriers with better intracellular delivery characteristics. In our collaboration, programmed lipopolyplexes with deshieldable PEGylation were designed (Nie Biomaterials 2011). This intracellularly more effective platform will now be merged with the dual-ligand targeted strategy. Lipopolyplexes will be generated by physical association of polyplexes with targeting peptide-PEG-cholesterol containing liposomes (with or without cleavable PEG linkers). Alternatively, chemical conjugated lipopolymers will be the basis for targeted lipopolyplexes. Established (RGD, B6) and new (such as GE11, folate, TAT) ligands will be evaluated in the lipopolyplexes. The study will explore mechanisms of dual targeting ligand combinations in different cancer types (beyond prostate cancer, such as neuroblastom, hepatocellular carcinoma), especially the effect on cell association and intracellular uptake kinetics, and overall transfection activity. Stable or pH/reductive-deshieldable PEGylation will be compared.