VEGF-based targeted imaging of tumor vasculature

基于 VEGF 的肿瘤脉管系统靶向成像

• 批准号: 6882122
• 负责人: Joseph M Backer
• 金额: $ 19.68万
• 依托单位: SIBTECH, INC.
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-08 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6882122
• 关键词: bioimaging /biomedical imaging; biomaterial development /preparation; cardiovascular imaging /visualization; contrast media; cyanine; diagnosis design /evaluation; growth factor receptors; laboratory mouse; neoplasm /cancer blood supply; neoplasm /cancer diagnosis; technetium; vascular endothelial growth factors

DESCRIPTION (provided by applicant): The overall goal of this project is to develop a highly sensitive system for cancer diagnostics based on targeted imaging of tumor neovasculature. Formation of new blood vessels through processes of angiogenesis and vasculogenesis is common, unique, and one of the earliest features of primary tumors and metastatic lesions. Timely imaging of functional biomarkers in tumor neovasculature will provide formidable opportunities for cancer diagnostics and treatment. In this respect, endothelial cell specific receptors for vascular endothelial growth factor (VEGF), such as VEGFR-2 (KDR/Flk-1), are particularly attractive targets, because they are over-expressed in tumor but not normal vasculature. Although VEGF would be a natural choice for targeted imaging of tumor vasculature, development of VEGF-based diagnostics is severely hindered by inactivation of this fragile molecule upon conjugation of contrast agents. To solve this problem for VEGF and other fragile targeting proteins, we have recently engineered a novel 15- aa humanized tag for genetic fusion to recombinant proteins. This tag, named Hu(C4), contains an unpaired cysteine available for site-specific modification via standard SH-directed chemistries. In our preliminary experiments we found that bacterially expressed Hu(C4)-VEGF fusion protein is functionally active and retains activity after site-specific modification of Hu(C4) with bulky (approximately 56 kDa) construct. We hypothesize that conjugation of contrast agents to one or two Hu(C4)-tags in VEGF will not destroy its functional activity. In Phase I of this project we will test this hypothesis with two types of contrast agents. First, we will derivatize Hu(C4)-VEGF with a cyanine dye Cy5.5 for near-infrared optical imaging and test constructs in vitro and in vivo. If successful, Cy5.5-Hu(C4)-VEGF would become a powerful and commercially viable tool for research and development of anti-cancer therapeutics in animal models. Second, we will derivatize Hu(C4)-VEGF with a 99mTc chelator hydrazinonicotinamide (HYNIC) and test this construct in vitro. Finally, we will optimize production Hu(C4)-VEGF to the level sufficient for animal studies. Accomplishing these specific aims will determine feasibility of VEGF-based imaging. We expect that Cy5.5- Hu(C4)-VEGF would be ready for commercialization after completion of Phase I. In Phase II we will perform animal studies with HYNIC-Hu(C4)-VEGF, undertake formal toxicology studies for this construct, and develop GMPcompatible production of Hu(C4)-VEGF.

描述(由申请人提供)： 该项目的总体目标是开发一种基于肿瘤新生血管靶向成像的高度敏感的癌症诊断系统。通过血管生成和血管生成过程形成新的血管是常见的、独特的，也是原发肿瘤和转移性病变最早的特征之一。肿瘤新生血管中功能生物标志物的及时成像将为癌症的诊断和治疗提供巨大的机会。在这方面，血管内皮生长因子(VEGF)的内皮细胞特异性受体，如VEGFR-2(KDR/Flk-1)是特别吸引人的靶点，因为它们在肿瘤中过度表达，而在正常血管中不表达。虽然血管内皮生长因子是肿瘤血管靶向成像的自然选择，但这种脆弱的分子在对比剂结合时失活，严重阻碍了基于血管内皮生长因子的诊断的发展。 为了解决血管内皮生长因子和其他脆性靶向蛋白的这一问题，我们最近设计了一种新型的15个氨基酸的人源化标签，用于基因融合重组蛋白。该标签命名为HU(C4)，包含一种未配对的半胱氨酸，可通过标准的SH定向化学作用进行位点特异性修饰。在我们的初步实验中，我们发现细菌表达的HU(C4)-血管内皮生长因子融合蛋白具有功能活性，并在HU(C4)与大体积(约56 kDa)结构的定点修饰后保持活性。我们假设，将造影剂与血管内皮生长因子中的一个或两个HU(C4)标记偶联不会破坏其功能活性。 在这个项目的第一阶段，我们将用两种类型的造影剂来检验这一假设。首先，我们将用一种用于近红外光学成像的菁染料Cy5.5来衍生化Hu(C4)-VEGF，并在体外和体内测试构建物。如果成功，Cy5.5-Hu(C4)-VEGF将成为在动物模型中研究和开发抗癌疗法的强大和商业可行的工具。其次，我们将用99mTc螯合剂肼烟酰胺(HYNIC)衍生HU(C4)-血管内皮生长因子，并在体外对其进行测试。最后，我们将优化HU(C4)-VEGF的生产，使其达到足以进行动物研究的水平。 这些特定目标的实现将决定基于血管内皮生长因子的成像的可行性。我们预计，在第一阶段完成后，Cy5.5-HU(C4)-VEGF将可以商业化。在第二阶段，我们将与HYNIC-HU(C4)-VEGF进行动物实验，对该构建物进行正式的毒理学研究，并开发与GMP兼容的Hu(C4)-VEGF生产。