Growth Factor as Anti-angiogenesis Agents

描述（由申请人提供）：该提案的总体目标是基于设计结合多肽生长因子并破坏受体酪氨酸激酶（RTK）致癌信号传导的小合成分子，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着重要作用。大多数人类癌症过表达GF和/或RTK，这与转移、预后差、对化疗的抗性和缩短的患者存活时间有关。此外，人类癌症分泌促血管生成GF，如VEGF和PDGF，其促进新血管形成，这是实质性肿瘤生长所需的步骤。靶向GF/RTK信号传导以发现新型抗癌药物的进一步验证来自证明抗GF和抗RTK抗体、GF的显性负性形式和RTK的酪氨酸激酶抑制剂导致在动物模型中抑制人肿瘤生长和血管生成的研究。该项目所基于的假设是，结合PDGF、EGF和VEGF的合成分子将阻断它们的生物学功能，将破坏RTK信号传导，并将阻断肿瘤发生和血管生成。为了验证这一假设，提出了以下具体目标：（1）设计蛋白质表面结合化合物的文库，并通过使用全细胞高通量受体酪氨酸磷酸化测定来评估它们破坏各自RTK的PDGF、EGF和VEGF活化的能力。（二） 确定通过特定目的#1的构效关系研究鉴定的化合物结合其各自GF、抑制GF与其RTK结合、抑制RTK依赖性信号传导、DNA合成、细胞周期进展、增殖、恶性转化和诱导细胞凋亡的能力。通过使用已知依赖于特定GF和/或其RTK进行恶性转化的人癌细胞来确定GFBs的选择性。NIH 3 T3细胞被工程化以过表达特异性RTK，如EGFR、PDGFR和Flk-1（VEGFR），以及被其他癌基因转化的细胞，如Ras、Src和ErbB 2，也将用于建立选择性。(3)通过体外和体内试验，如毛细血管网络形成、内皮细胞增殖和迁移以及大鼠动脉和角膜血管生成试验，确定GFBs的抗血管生成潜力。(4)评价选择性破坏RTK致癌信号传导的生长因子结合分子在使用GF/RTK信号传导异常激活的鼠和人肿瘤的动物模型中抑制肿瘤生长和血管生成的能力。确定GFB电极导线在动物中的毒性。提出的研究将导致发现具有抗癌和抗血管生成活性的GF结合合成分子，并最终拓宽可以成功治疗的人类肿瘤的范围。

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.