RGD-Polymer Targeting Plasmid to Angiogenic Endothelium

描述（由申请人提供）： 将设计新的靶向血管生成内皮细胞的聚合物载体。阳离子聚合物聚乙烯亚胺（PEI）将通过亲水性聚乙二醇（PEG）间隔基与avb 31 avb 5整联蛋白结合RGD-4C肽ACDCRGDCFC缀合。这种设计的载体将用于递送抗血管生成质粒。与正常组织相比，血管生成内皮细胞中α-v-β 3和α-v-β 5整联蛋白的显著过表达提供了实体瘤的特异性靶向。PEI使DNA浓缩并且是亲内体的，从而保护抗血管生成质粒DNA并将其递送到靶细胞中。此外，PEG间隔基增加了载体的溶解度并降低了PEI毒性。此外，这种聚合物载体是非免疫原性的，并且出于实际目的可以容易地大量生产。使用PEI-PEG-RGD载体，初步数据显示质粒DNA对靶细胞的高特异性和转染。将产生含有内源性血管生成抑制剂、可溶性Flt-1和FIk-1受体和新构建的治疗基因pDHFR-p53的质粒构建体。在广泛表征后，将使用载体进行体外研究、大鼠恶性神经胶质瘤和小鼠刘易斯肺癌动物模型（局部和全身递送途径）。已经研究了许多靶向肿瘤脉管系统的内源性抑制剂，并且它们在动物中的全身施用抑制肿瘤的生长和转移。然而，重组蛋白的生产已被证明是困难的，并且有效治疗需要高剂量。此外，全身性蛋白质治疗包括重复注射以延长治疗时间，这对于给药来说是不方便的并且成本高。基因治疗，利用这些内源性血管生成抑制剂，可以缓解这些问题。这些结果将是有价值的资产，提供标准的基因输送在治疗癌症使用抗血管生成基因。

DESCRIPTION (provided by applicant): New polymer carrier targeting to angiogenic endothelial cells will be designed. The cationic polymer, polyethylenimine (PEI) will be conjugated with the avb31avb5 integrin binding RGD-4C peptide, ACDCRGDCFC via hydrophilic polyethylene glycol (PEG) spacer. This designed carrier will be used for the delivery of antiangiognesis plasmids. The significant over expression of alpha-v-Beta3 and alpha-v-Beta5 integrins in angiogenic endothelial cells provides specific targeting of solid tumors compared to normal tissue, PEI condenses DNA and is endosomotropic, thereby protecting and delivering antiangiogenic plasmid DNA into target cells. In addition, the PEG spacer increases the solubility of the carrier and reduces PEI toxicity. Furthermore, this polymeric carrier is nonimmunogenic and for practical purposes can be easily mass-produced. Using the PEI-PEG-RGD carrier, preliminary data shows high specificity and transfection of plasmid DNA to the target cells. Plasmid constructs will be generated containing the endogeneous angiogenic inhibitors, solublized Flt-1 and FIk-1 receptors and the newly constructed therapeutic gene, pDHFR-p53. After extensive characterization, in vitro studies, rat malignant glioma, and murine lewis lung carcinoma animal models will be used (local and systemic delivery routes) with the carrier. A number of endogenous inhibitors targeting tumor vasculature have been studied and their systemic administration in animals suppresses the growth of tumor and metastases. However, production of recombinant proteins has proven to be difficult and high doses are required for effective treatment. In addition, systemic protein therapy includes repeated injections for prolonged treatment, which is inconvenient for administration and costly. Gene therapy, utilizing these endogenous angiogenesis inhibitors, can alleviate these problems. The results will be valuable assets to provide criteria for gene delivery in the treatment of cancer using antiangiogenesis genes.