Growth Factor as Anti-angiogenesis Agents

描述（由申请人提供）：本提案的总体目标是通过设计结合多肽生长因子和破坏受体酪氨酸激酶（RTK）致癌信号的小合成分子，发现新的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着核心作用。大多数人类癌症过度表达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GF，如VEGF和PDGF，促进新血管的形成，这是实质性肿瘤生长的必要步骤。研究表明，在动物模型中，抗GF和抗RTK抗体、GF的主要阴性形式和RTK的酪氨酸激酶抑制剂可抑制人类肿瘤生长和血管生成，从而进一步验证了靶向GF/RTK信号通路以发现新型抗癌药物的可行性。本项目基于的假设是，结合PDGF、EGF和VEGF的合成分子会阻断它们的生物学功能，破坏RTK信号，阻断肿瘤发生和血管生成。为了验证这一假设，我们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破坏PDGF、EGF和VEGF各自RTKs激活的能力。（2)

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.