Targeting Urokinase Pathway for Breast Cancer Therapy

描述（由申请人提供）：潜在的分子机制 导致乳腺癌的进展和维持恶性肿瘤 表型可能涉及生长因子触发的信号级联反应， 丝氨酸蛋白酶的活化。例如，过度表达EGF和 HER 2受体和尿激酶纤溶酶原激活剂（uPA）通常是 与侵袭性临床病程、较短的无病生存期相关 在人类乳腺癌中，周期、预后差和转移增加。更 最近，调蛋白（HRG），一种HER 3和HER 4受体的组合配体， 已被确定为预测不良预后的独立标志物。 近年来，涉及干扰和/或阻断 抗受体单克隆抗体介导的HER-介导的自分泌/旁分泌生长刺激， 一直是控制乳腺癌生长的积极研究的对象 细胞增殖人源化mAb 225（C225）和mAb 4D 5（赫赛汀）是 目前正在进行II期和III期多中心临床试验， 与其它抗癌剂组合。至于尿激酶，因为 尿激酶型纤溶酶原激活剂（uPA）依赖的细胞周活化 蛋白水解和侵袭依赖于uPA对其受体的定位， uPAR，阻断这种相互作用也可能导致肿瘤抑制 进展和血管生成。 我们的目的是研究HRG调节的信号通路 uPA/uPAR系统的表达和激活，并建立 特异性uPAR抑制剂（A36）单独或联合 与C225或赫赛汀联合用于抑制乳腺癌进展至 更具侵袭性的表型 我们的工作假设是，“自分泌或旁分泌激活的 uPA/uPAR系统或HRG或两者都有助于增加细胞周侵袭 乳腺癌细胞;这一途径可能是积极的影响， 间质生长对肿瘤细胞中HER 2和EGFR的反式激活 因子HRG;用A36和赫赛汀或C225靶向uPA/uPAR可能 抑制乳腺癌的发展。" 这项建议的理由是基于最近提出的意见 主要研究者和同事认为（i）HRG刺激 uPA/uPAR的表达和激活以及侵袭;（ii）特异性uPAR 抑制剂（A36）阻断HRG介导的侵袭;（iii）A36抑制VEGF 在具有活化的uPA/uPAR的乳腺癌细胞中的启动子活性;（iv）A36 抑制内皮细胞管的形成;（v）C225和赫赛汀阻断了内皮细胞管的形成。 EGFR水平正常的浸润性乳腺癌细胞中uPAR的表达 和HER 2;和（vi）HRG过表达与短期无病 乳腺癌患者的生存率。我们认为HRG是一种间充质细胞， 生长因子，可能在上调uPAR对肿瘤的作用中起重要作用 通过引发uPA最终激活uPA-uPAR级联反应， 并将uPAR拮抗剂A36与抗受体结合 mAb可增强体内抗侵袭和抗血管生成特性/活性。 本研究的具体目的是：（1）确定 HRG和HER调节uPA/uPAR系统的机制;（2） 检查A36和赫赛汀或C225在体外临床前的作用， 研究uPA/uPAR在肿瘤转移中的意义。 与HRG作为人类乳腺癌预后因素的关系。一个独特方面 我们的建议是阐明HRG调节uPA/uPAR的机制 和侵袭，这将为转移性肝癌的治疗提供新的理论基础。 通过uPAR抑制剂和抗受体单克隆抗体Herceptin或C225对人乳腺肿瘤的作用。 这些结果将对开发新的治疗方法产生直接影响。 干预策略。

DESCRIPTION (provided by applicant): The underlying molecular mechanisms leading to breast cancer progression and maintenance of the malignant phenotypes may involve a growth factor-triggered signaling cascade leading to the activation of serine proteases. For example, overexpression of the EGF and HER2 receptors, and urokinase plasminogen activator (uPA) are frequently associated with an aggressive clinical course, shorter disease-free survival periods, poor prognosis, and increased metastasis in human breast cancer. More recently heregulin (HRG), a combinational ligand for HER3 and HER4 receptors, has been identified as an independent marker that predicts poor prognosis. In recent years, approaches involving interference with and/or blocking of HER-mediated autocrine/paracrine growth stimulation by anti-receptor mAbs have been the subject of active investigation to control the growth of breast cancer cell proliferation. Humanized mAb 225 (C225) and mAb 4D5 (Herceptin) are currently in phase II and phase III multicenter clinical trials, both alone and in combination with other anticancer agents. As for urokinase, because the activation of urokinase plasminogen activator (uPA)-dependent pericellular proteolysis and invasion depends on the localization of uPA to its receptor, uPAR, blocking this interaction may also lead to inhibition of tumor progression and angiogenesis. We purpose here to investigate the signaling pathways by which HRG regulates the expression and activation of the uPA/uPAR system, and to establish the clinical efficacy of a specific uPAR inhibitor (A36) either alone or in combination with C225 or Herceptin for suppressing breast cancer progression to more invasive phenotypes. Our working hypotheses are that "autocrine or paracrine activation of the uPA/uPAR system or HRG or both contributes to increased pericellular invasion of breast cancer cells; that this pathway may be positively influenced by the transactivation of HER2 and EGFR in tumor cells by the mesenchymal growth factor HRG; and that targeting uPA/uPAR with A36 and Herceptin or C225 may inhibit the progression of breast cancer." The rationale behind this proposal is based on the observations recently made by the Principal Investigator and colleagues that (i) HRG-stimulates the expression and activation of uPA/uPAR and invasion; (ii) a specific uPAR inhibitor (A36) blocked HRG-mediated invasion; (iii) A36 inhibited the VEGF promoter activity in breast cancer cells that have activated uPA/uPAR; (iv) A36 inhibited endothelial cell tube formation; (v) C225 and Herceptin blocked the uPAR expression in invasive breast cancer cells that have normal levels of EGFR and HER2; and (vi) HRG overexpression was associated with a short disease-free survival in patients with breast cancer. We believe that HRG, a mesenchymal growth factor, may have a significant role in the upregulation of uPAR on tumor cells by priming them for eventual activation of the uPA-uPAR cascade by uPA from stromal cells and combining the uPAR antagonist A36 with an anti-receptor mAb may enhance anti-invasive and anti-angiogenic properties/activity in vivo. The Specific Aims of this proposal are: (1) to determine the molecular mechanism by which HRG and the HERs regulate the uPA/uPAR system; (2) to examine the effects of A36 and Herceptin or C225 in preclinical in vitro and animals metastasis studies; and (3) to examine the significance of uPA/uPAR in relation to HRG as prognostic factors in human breast cancer. A unique aspect of our proposal is delineation of the mechanism by which HRG regulates uPA/uPAR and invasion, which will provide a novel rationale for therapy of metastatic human breast tumors by uPAR inhibitor and anti-receptor mAbs Herceptin or C225. These results will have a direct impact in developing novel therapeutic intervention strategies.