Novel Angiogenesis Inhibitors Targeting the Anthrax Toxin Receptors

描述(申请人提供)：血管生成依赖性疾病是发达国家致盲的主要原因，仍然需要广泛有效的抗血管生成疗法，而不只是抑制单一的生长因子。我们发现炭疽保护性抗原突变体(如PASSSR)能有效抑制多种生长因子诱导的角膜新生血管形成。我们的长期目标是了解这种抑制的机制，并在此机制的基础上开发适当的疗法。我们的工作假设是，内源性配体(S)与炭疽毒素受体(ANTXR1/TEM8和/或ANTXR2/CMG2)的结合在血管生成过程中是重要的，竞争配体抑制这种相互作用将抑制血管生成。我们将采用几种策略来检验这一假设。首先，我们将解释PASSSR抗血管生成活性的生化机制。我们将确定介导PASSSR抑制的抗血管生成效应的特异性受体(S)和与该效应相关的信号分子(S)。其次，我们将鉴定小分子ATR抑制剂，并评估它们的体外抗血管生成特性。作为美国国立卫生研究院路线图倡议的一部分，将使用高通量筛选试验分离相关的小分子抑制剂。然后，将在组织培养中评估已鉴定的分子的抗血管生成活性。第三，我们将评估分离的ATR抑制剂在体内抑制眼血管生成的能力。抗血管生成活性将使用两种眼血管生成的小鼠模型进行评估：角膜新生血管模型和激光诱导的脉络膜新生血管模型。这些研究的成功完成将使炭疽毒素受体(S)成为抗血管生成治疗的合适靶点，并为广谱抗血管生成治疗提供小分子先导化合物。因此，这项提案的成功完成将涵盖眼部血管生成障碍，如黄斑变性、糖尿病视网膜病变、早产儿视网膜病变和青光眼、与疱疹病毒性角膜炎、沙眼、烧伤和角膜移植血管重建等疾病相关的角膜新生血管，以及其他依赖血管生成的疾病，如癌症、关节炎和心血管疾病。因此，这些研究可能会对人类健康产生重大影响。与公共卫生相关。我们已经证明，炭疽毒素受体的大蛋白抑制剂可以抑制角膜新生血管和其他血管生成依赖的疾病。我们试图了解这种抑制发生的机制，并确定具有类似活性的小分子。这些分子或类似的分子可用于治疗角膜新生血管和其他血管生成依赖型疾病(例如黄斑变性、糖尿病视网膜病变、早产儿视网膜病变、癌症、心血管疾病、关节炎等)。

DESCRIPTION (provided by applicant): Angiogenesis dependant disease is a major cause of blindness in the developed world, and there remains a generalized outstanding need for broadly active antiangiogenesis therapies which do not inhibit just a single growth factor. We have discovered that anthrax protective antigen mutants (e.g. PASSSR) can powerfully suppress corneal neovascularization induced by multiple growth factors. Our long-range goal is to understand the mechanism by which this suppression is accomplished and develop appropriate therapeutics based on this mechanism. Our working hypotheses is that binding of endogenous ligand(s) to the anthrax toxin receptors (ANTXR1/TEM8 and/or ANTXR2/CMG2) is important in angiogenic processes, and that inhibition of this interaction by competing ligands will inhibit angiogenesis. We will employ several strategies to test this hypothesis. First, we will explain the biochemical mechanism responsible for the observed antiangiogenic activity of PASSSR. We will definitively identify both the specific receptor(s) that mediate the antiangiogenic effect inhibited by PASSSR and the signaling molecule(s) associated with that effect. Second, we will identify small molecule ATR inhibitors and assess their antiangiogenic properties ex vivo. Relevant small molecule inhibitors will be isolated using high throughput screening assays developed as a part of the NIH Roadmap Initiative. The antiangiogenic activity of the identified molecules will then be evaluated in tissue culture. Third, we will assess the ability of isolated ATR inhibitors to inhibit ocular angiogenesis in vivo. Antiangiogenic activity will be evaluated using two mouse models of ocular angiogenesis: the corneal neovascularization model, and a laser-induced choroidal neovascularization model. Successful completion of these studies will both establish the anthrax toxin receptor(s) as appropriate targets for antiangiogenic therapy and provide small molecule lead compounds for broad spectrum antiangiogenic therapies. Pathologies addressed by successful completion of this proposal would thus encompass disorders of ocular angiogenesis such as macular degeneration, diabetic retinopathy, retinopathy of prematurity, and glaucoma, corneal neovascularization associated with conditions such as Herpetic Keratitis, Trachoma, burns, and revascularization of corneal transplants, and other angiogenesis-dependant diseases such as cancer, arthritis, and cardiovascular disease. Hence, these studies are likely to have a significant impact on human health. PUBLIC HEALTH RELEVANCE. We have shown that large protein inhibitors of the anthrax toxin receptors can inhibit corneal neovascularization and other angiogenesis-dependant diseases. We seek to understand the mechanism by which this inhibition occurs and identify small molecules with similar activity. These molecules, or similar molecules can then be used to treat corneal neovascularization, and other angiogenesis-dependant diseases (e.g. macular degeneration, diabetic retinopathy, retinopathy of prematurity, cancer, cardiovascular disease, arthritis, etc.).