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剂靶向递送到新生血管的部位。这是一种被广泛接受的策略，但部分受到交付和验证技术的限制。拟议的研究围绕着一种新的、生物相容性的递送装置——纳米颗粒（NP），作为一种手段，提供持续的、靶向的血管抑制剂递送到血管生成部位：伤口和肿瘤。该递送系统的关键要素是低毒性和基于带电聚合物对相互作用的组分柔韧性。作为一个模型系统，我们利用了新的肽类似物血栓反应蛋白-1 （TSP-1）先前显示具有血管抑制特性。为了在NP中提供保留，这些肽被制备成聚乙二醇偶联物，既保留肝素结合又保留生物活性。与空NP相比，用TSP-1肽偶联物制备的NP具有明显不同的生物分布和新血管形成部位的定位。本研究旨在实现三个目标：(1)优化NP制剂，包括剂量设置和其他靶向药物的结合；(2)利用成像和示踪技术确定靶向NP在小鼠体内的生物分布；(3)验证含有血管抑制剂的NP靶向递送到伤口和肿瘤的有效性。在进一步的研究中，载脂蛋白E衍生的肽序列将被整合到纳米颗粒中，以增强内皮细胞的选择性靶向。肿瘤的传递和靶向性将通过荧光素酶生物发光、123i成像和钆造影剂磁共振成像等无创成像技术进行测试。传统的示踪技术和荧光标记NP的显微定位也将被应用。在体内，将通过功率多普勒超声确定肿瘤血管的实时图像分析，并通过磁共振成像确定肿瘤肿块。此外，传统的形态计量学和组织学技术将用于量化这种新型药物输送系统的功效。目的是设计药物输送系统，以病理血管生成为目标，对正常血管系统的影响最小。

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.