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）： 该项目的总体目的是基于肿瘤新生血管的靶向成像开发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血管是常见的，独特的，并且是原发性肿瘤和转移性病变的最早特征之一。及时对肿瘤新生血管中功能性生物标志物的成像将为癌症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）（例如VEGFR-2（KDR/FLK-1））的内皮细胞特异性受体是特别有吸引力的靶标，因为它们在肿瘤中过表达，但不是正常的脉管系统。尽管VEGF将是对肿瘤脉管系统的靶向成像的自然选择，但基于VEGF的诊断的发展受到这种脆弱的分子的灭活而严重阻碍了对比剂。 为了解决VEGF和其他脆弱靶向蛋白的问题，我们最近设计了一个新型的15 aa人源化标签，用于重组蛋白质的遗传融合。该标签名为HU（C4），包含一种未配对的半胱氨酸，可通过标准的SH指导化学物质进行特定于现场的修饰。在我们的初步实验中，我们发现细菌表达的HU（C4）-VEGF融合蛋白在功能上具有活性，并且在用笨重（约56 kDa）结构的HU（C4）修饰位点特异性修饰后保持活性。我们假设VEGF中的对比剂与一个或两个HU（C4）标记的对比剂的结合不会破坏其功能活性。 在该项目的第一阶段，我们将用两种类型的对比剂检验该假设。首先，我们将用氰染料CY5.5衍生hu（C4）-VEGF，以用于近红外光学成像和体内测试构建体。如果成功的话，CY5.5-HU（C4）-VEGF将成为动物模型中抗癌疗法的研究和开发的强大且商业上可行的工具。其次，我们将使用99mtc螯合剂氢嗪氨基酰胺（Hynic）衍生化HU（C4）-VEGF，并在体外测试该构建体。最后，我们将优化生产HU（C4）-VEGF达到足以用于动物研究的水平。 完成这些特定目标将确定基于VEGF的成像的可行性。我们预计Cy5.5- HU（C4）-VEGF将在I阶段完成后准备好进行商业化。在第二阶段，我们将使用Hynic-Hu（C4）-VEGF进行动物研究，对该结构进行正式的毒理学研究，并开发GMPCompyable-Comcomcyable的HU（C4）-VEGFF。