Nanoparticle Targeting to Control Angiogenesis

描述(由申请人提供)：该项目的目标是实现血管抑制药物的定向输送到新生血管的部位。这是一种被广泛接受的战略，但在一定程度上受到交付和验证技术的限制。拟议的研究围绕着一种新型的、生物相容的递送装置--纳米微粒(NP)，作为一种向血管生成部位(伤口和肿瘤)提供持续的、靶向的血管抑制剂递送的手段。传递系统的关键元素是低毒性和组成灵活性，基于带电聚合物对的相互作用。作为一个模型系统，我们利用了先前被证明具有血管抑制特性的新型血栓反应蛋白-L(TSP-1)的多肽类似物。为了在NP内提供保留，这些多肽被制备成既保留肝素结合又保持生物活性的聚乙二醇偶联物。用TSP-1多肽结合物制备的NP具有明显不同于空白NP的生物分布和对新生血管部位的定位。这项建议旨在实现三个目标：(1)优化NP配方，包括设定剂量和加入其他靶向制剂；(2)使用成像和示踪技术来确定靶向NP在小鼠体内的生物分布；(3)验证含有血管抑制剂的NP靶向输送到伤口和肿瘤的有效性。在进一步的研究中，来自载脂蛋白E的多肽序列将被加入到纳米颗粒中，以增强对内皮细胞的选择性靶向。肿瘤的传递和靶向将通过使用荧光素酶生物发光的非侵入性成像、123I-闪烁成像和具有Gd对比的磁共振成像来测试。常规示踪技术和荧光标记NP的显微定位也将被应用。在体内，通过能量多普勒超声对肿瘤血管进行实时图像分析，通过磁共振成像确定肿瘤质量。此外，传统的形态计量学和组织学技术将被用来量化这种新的药物输送系统的效果。我们的目标是设计药物输送系统，该系统将专门针对病理性血管生成，并将对正常血管系统的影响降至最低。

DESCRIPTION (provided by applicant): The goal of this project is to achieve targeted delivery of angiostatic agents to sites of neovascularization. This is a widely accepted strategy that is limited in part by technologies of delivery and validation. The proposed studies center around a novel, biocompatible delivery device, the nanoparticle (NP), as a means to provide sustained, targeted delivery of angiostatic agents to sites of angiogenesis: wounds and tumors. The key elements of the delivery system are low toxicity and compositional flexibility, based interactions of charged polymer pairs. As a model system, we have utilized novel peptide analogs of thrombospondin-l (TSP-1) previously shown to have angiostatic properties. To provide retention within NP, these peptides have been prepared as polyethylene glycol conjugates that retain both heparin binding and biological activity. NP prepared with TSP-1 peptide conjugates show a markedly different biodistribution than empty NP and localization to sites of neovascularization. This proposal sets out to accomplish three goals: (1) optimization of the NP formulation, including dose-setting and incorporation of other targeting agents; (2) use of imaging and tracer technologies to ascertain biodistribution of targeted NP in mice; (3) validation of the efficacy of targeted delivery of NP containing angiostatic agents to wounds and tumors. In further studies, a peptide sequence derived from apolipoprotein E will be incorporated into the nanoparticle to enhance selective targeting of endothelial cells. Tumor delivery and targeting will be tested by noninvasive imaging using luciferase bioluminescence, 123I-scintigraphic imaging, and magnetic resonance imaging with gadolinium contrast. Conventional tracer technologies and microscopic localization of fluorescently labeled NP will be applied as well. In vivo, real-time image analysis of tumor vascularity will be determined by power Doppler ultrasound, and tumor mass will be determined by magnetic resonance imaging. In addition, conventional morphometric and histological techniques will be used to quantify the efficacy of this novel drug delivery system. The objective is to design drug delivery systems that will specifically target pathological angiogenesis with minimal effects on the normal vasculature.