Inhibition of VEGF Mediated Angiogenesis by TIMP-3

描述(由申请者提供)：新生血管对于支持肿瘤的实质性生长至关重要。对于广泛的肿瘤，复杂的微血管伴随着从增生到肿瘤的转变，从低级别到高级别的进展和增强的转移能力。研究表明，更多的血管通常预示着更具侵袭性的癌症。因此，靶向肿瘤的新血管已成为治疗肿瘤的一种很有前途的方法。我们最近证实，基质金属蛋白酶的内源性抑制因子TIMP-3(TIMP-3)是血管内皮生长因子(VEGF)介导的血管生成的有效抑制因子。TIMP-3可阻断血管内皮生长因子与其受体KDR的结合。令人惊讶的是，TIMP-3介导的这种血管抑制作用不依赖于其对基质金属蛋白酶的抑制活性。这些结果使我们假设TIMP-3是一种有效的内源性血管生成抑制物，在肿瘤发生中发挥关键作用。我们建议研究TIMP-3和KDR相互作用的分子模型。基于这些结果，我们将确定TIMP-3具有血管抑制功能但缺乏基质金属蛋白酶抑制活性的结构域。由于TIMP-3和血管内皮生长因子都与硫酸肝素蛋白多糖结合，我们将确定肝素/硫酸肝素结合对TIMP-3的血管抑制活性的结构基础和潜在作用。我们还将研究血管内皮生长因子介导的血管生成和TIMP-3缺陷小鼠的肿瘤生长。从长远来看，了解TIMP-3调节新生血管的分子机制将有助于设计治疗干预措施，以防止肿瘤的自由生长。 具体目标： 1.确定参与TIMP-3/KDR相互作用的TIMP-3和KDR结构域。 2.确定肝素/硫酸肝素结合对TIMP-3血管抑制活性的影响。 3.检测血管内皮生长因子对TIMP-3基因缺失小鼠的血管生成和肿瘤生长的影响。

DESCRIPTION (provided by applicant): Neovascularization is critical for the support of substantial tumor growth. For a wide range of tumors, a complex microvasculature accompanies the transition from hyperplasia to neoplasia, a progression from low to high-grade classification and enhanced metastatic capacity. Studies have demonstrated that a greater number of blood vessels often predict a more aggressive cancer. Thus targeting the new blood vessels of the tumor has been a promising approach for the treatment of tumors. We have recently demonstrated that Tissue Inhibitor of Metalloproteinases-3 (TIMP-3), an endogenous inhibitor of matrix metalloproteinases (MMP), is a potent inhibitor of Vascular Endothelial Growth Factor (VEGF) mediated angiogenesis. TIMP-3 can block the binding of VEGF specifically to its receptor, KDR on the surface of endothelial cells. Surprisingly, TIMP-3 mediates this angiostatic effect independent of its MMP inhibitory activity. These results led us to hypothesize that TIMP-3 is a potent endogenous angiogenesis inhibitor and plays a critical role in tumorigenesis. We propose to study the molecular modeling of TIMP-3 and KDR interactions. Based on these results, we will identify domains of TIMP-3 that have the angiostatic function but are devoid of MMP inhibitory activity. Since both TIMP-3 and VEGF bind heparan sulfate proteoglycans, we will determine the structural basis and potential role of heparin/heparan sulfate binding to the angiostatic activity of TIMP-3. We will also examine VEGF mediated angiogenesis and tumor growth in mice deficient in Timp-3. In the long term, the understanding of the molecular mechanisms of regulation of neovascularization by TIMP-3 will help in the design of therapeutic interventions to prevent unfettered growth of tumors. Specific Aims: 1. To identify the TIMP-3 and KDR domains involved in TIMP-3/KDR interaction. 2. To determine the potential role of heparin/heparan sulfate binding on the angiostatic activity of TIMP-3. 3. To determine the VEGF mediated angiogenic response and tumor growth in TIMP-3 null mice.