Growth Factor as Anti-angiogenesis Agents

描述(申请人提供)：该提案的总体目标是基于设计结合多肽生长因子和干扰受体酪氨酸激酶(RTK)致癌信号的小分子合成分子，发现新型抗癌药物和抗血管生成药物。生长因子(GF)如EGF、PDGF和VEGF及其受体在肿瘤发生和血管生成中起核心作用。大多数人类肿瘤过度表达GF和/或RTKs，这与转移、预后不良、化疗耐药和患者生存时间缩短有关。此外，人类癌症分泌促血管生成的生长因子，如血管内皮生长因子和血小板衍生生长因子，促进新的血管形成，这是肿瘤实质性生长所必需的步骤。靶向GF/RTK信号以发现新的抗癌药物的进一步验证来自于研究表明，抗GF和抗RTK抗体、显性阴性形式的GF和RTK的酪氨酸激酶抑制剂在动物模型中导致抑制人类肿瘤生长和血管生成。这个项目所基于的假设是，与PDGF、EGF和VEGF结合的合成分子将阻断它们的生物学功能，将干扰RTK信号转导，并将阻止肿瘤发生和血管生成。为了验证这一假说，提出了以下具体目标：(1)设计蛋白质表面结合化合物文库，并通过全细胞高通量受体酪氨酸磷酸化实验评估它们干扰PDGF、EGF和VEGF激活各自RTK的能力。(2) 通过对特定AIMS#1的构效关系研究，确定化合物与其各自的生长因子结合的能力，抑制生长因子与其RTK的结合，抑制RTK依赖的信号转导、DNA合成、细胞周期进展、增殖、恶性转化和诱导细胞凋亡。通过利用已知依赖于特定GFS和/或其RTK进行恶性转化的人类癌细胞，建立GFBs的选择性。NIH 3T3细胞被设计为过表达特定的RTK，如EGFR、PDGFR和Flk-1(VEGFR)，以及由其他癌基因如Ras、Src和ErbB2转化的RTK，也将用于建立选择性。(3)通过毛细血管网络形成、血管内皮细胞增殖和迁移、大鼠动脉和角膜血管生成实验等体内外实验，研究银杏叶提取物的抗血管生成作用。(4)研究选择性阻断RTK致癌信号的生长因子结合分子在小鼠和人肿瘤模型中抑制肿瘤生长和血管生成的能力。目的：测定GFB铅对动物的毒性。所提出的研究将导致发现具有抗肿瘤和抗血管生成活性的与GF结合的合成分子，并最终拓宽可成功治疗的人类肿瘤的光谱。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to discover novel anti-cancer drugs and anti-angiogenic drugs based on designing small synthetic molecules that bind polypeptide growth factors and disrupt receptor tyrosine kinases (RTK) oncogenic signaling. Growth factors (GF) such as EGF, PDGF and VEGF and their receptors play a central role in oncogenesis and angiogenesis. The majority of human cancers overexpress GF and/or RTKs, and this has been associated with metastasis, poor prognosis, resistance to chemotherapy and shortened patient survival time. Furthermore, human cancers secrete pro-angiogenic GF such as VEGF and PDGF which promote new blood vessel formation, a required step for substantial tumor growth. Further validation for targeting GF/RTK signaling to discover novel anti-cancer drugs comes from studies that demonstrated that anti-GF and anti-RTK antibodies, dominant negative forms of GF and tyrosine kinase inhibitors of RTKs lead to inhibition of human tumor growth and angiogenesis in animal models. The hypothesis upon which this project is based is that synthetic molecules that bind PDGF, EGF and VEGF will block their biological function, will disrupt RTK signaling and will block oncogenesis and angiogenesis. To test this hypothesis, the following specific aims are proposed: (1) to design libraries of protein surface binding compounds and to evaluate their ability to disrupt PDGF, EGF and VEGF activation of their respective RTKs by using a whole cell high throughput receptor tyrosine phosphorylation assay. (2) To determine the ability of the compounds, identified by the structure activity relationship studies of specific aims #1, to bind their respective GF, to inhibit binding of the GF to their RTK, to suppress RTK-dependent signaling, DNA synthesis, cell cycle progression, proliferation, malignant transformation and to induce apoptosis. To establish the selectivity of the GFBs by using human cancer cells that are known to be dependent on specific GFs and/or their RTKs for malignant transformation. NIH 3T3 cells that were engineered to overexpress specific RTKs such as EGFR, PDGFR, and Flk-1 (VEGFR) as well as those transformed by other oncogenes such as Ras, Src and ErbB2 will also be used to establish selectivity. (3) To determine the anti-angiogenic potential of GFBs by in vitro and in vivo assays such as capillary network formation, endothelial cell proliferation and migration and rat artery and cornea angiogenesis assays. (4) To evaluate the ability of growth factor binding molecules that selectively disrupt RTK oncogenic signaling, to inhibit tumor growth and angiogenesis in animal models using murine and human tumors where GF/RTK signaling is aberrantly activated. To determine toxicity in animals of GFB leads. The studies proposed will lead to the discovery of GF binding synthetic molecules with anti-oncogenic and anti-angiogenic activities, and will ultimately broaden the spectrum of human tumors that can be successfully treated.