Development of anti-angiogenesis therapy targeting integrin

描述（由申请人提供）：实体瘤在没有自身血液供应的情况下，直径不会超过3 - 4毫米。由于血管生成在肿瘤中的重要作用，抗血管生成、单一治疗或与其他治疗药物联合治疗是一种非常有前途的癌症治疗方法。取得了巨大的成功，如阿瓦斯汀，FDA批准的抗血管生成药物。然而，临床研究显示，抗血管生成药物对癌症患者生存的益处迄今为止微不足道。此外，目前大多数抗血管生成药物的开发研究主要集中在阻断VEGF/VEGFR信号的策略上。许多针对VEGF/VEGFR通路开发的药物通常会引起不必要的生物副作用。因此，迫切需要针对刺激和抑制肿瘤血管生成的其他生物学途径开发抗血管生成药物。我们已经开发了一类新的抗血管生成蛋白，通过整合在一个新的位点上，由¿v的i结构域和¿3的PSI结构域形成的大口袋。计算模型表明，大鼠CD2和人类CD2的结构域1在空间上非常适合设计的位点。在D1-CD2上引入的突变在设计蛋白和整合素之间架起了几个关键的联系，优化了设计蛋白与整合素的结合。所设计的蛋白在体外诱导HUVEC内皮细胞凋亡方面表现出较强的活性，对其他细胞无影响。肿瘤裸鼠PC-3异种移植实验表明，所设计的蛋白对肿瘤生长有较强的抑制作用。平行分析表明，我们开发的蛋白质抗血管生成药物在抑制肿瘤生长方面明显比阿瓦斯汀更有效。在本拟研究项目中，我们提出实验进一步验证设计的蛋白是否确实在设计位点与整合素相互作用，以及设计的蛋白是否确实通过靶向整合素发挥其活性。我们将通过各种人类癌症动物模型广泛测试开发的蛋白质抗血管生成剂的有效性。我们还设计了实验来测试我们开发的抗血管生成蛋白与其他抗癌药物联合治疗癌症是否有很大的效力。为了促进潜在的未来临床应用，我们提出了广泛表征蛋白质制剂的毒性和生物分布的实验。我们的研究将导致开发一种新的更有效的抗血管生成药物用于癌症治疗。

DESCRIPTION (provided by applicant): Solid tumors will not grow beyond 3 - 4 mm in diameter without building up their own blood supply. Due to the essential role of tumor angiogenesis, anti-angiogenesis, mono-therapy or in- combination with other therapeutic agents, represents a very promising approach for cancer treatments. Great successes have been achieved, such as Avastin, a FDA approved anti- angiogenesis drug. However, clinical studies revealed that the cancer patient survival benefits of antiangiogenic drugs have thus far been insignificant. In addition, most current studies in development of anti-angiogenesis agent have been mainly focused on strategies of blocking VEGF/VEGFR signaling. Many agents that are developed against the VEGF/VEGFR pathway often cause unwanted biologic side effects. There is urgent need to develop anti-angiogenesis agents by targeting many other biological pathways that are involved in both stimulation and inhibition of cancer angiogenesis. We have developed a new class of anti-angiogenesis proteins by integrin ¿v¿3 at a novel site, the large pocket formed by the I-domain of ¿v and the PSI domain of ¿3. Computational modeling demonstrated that the domain 1 of rat CD2 and human CD2 spatially fit into the designed site very well. Mutations introduced at the D1-CD2 to bridge several key contacts between designed protein and the integrins optimize the binding of the designed protein with integrin. The designed proteins exhibit strong in vitro activity in induction of apoptosis on endothelial HUVEC cells with no effects on other cells. Tests with tumor nude mice PC-3 xenografts show that the designed proteins strongly inhibit tumor growth. Parallel analyses suggested that our developed protein anti-angiogenesis agents are significantly more effective than Avastin in inhibiting tumor growth. In this proposed research project, we propose experiments to further verify whether the designed protein indeed interact with integrin at the designed site, and whether the designed protein indeed exert its activity by targeting the integrin. We will extensively test the effectiveness of the developed protein anti-angiogenesis agents by various animal models of human cancers. We also design experiments to test whether our developed anti-angiogenesis proteins will have great potency for cancer treatment in combination with other anti-cancer drugs. To facilitate potential future clinical applications, we propose experiments to extensively characterize toxicity and bio-distribution of the protein agents. Our study will lead to development of a new and more effective anti-angigenesis agent for cancer treatment.