Targeting Urokinase Pathway for Breast Cancer Therapy

描述(申请人提供)：潜在的分子机制 导致乳腺癌的恶性进展和维持 表型可能涉及生长因子触发的信号级联，从而导致 丝氨酸蛋白酶的激活。例如，EGF的过度表达和 HER2受体和尿激酶型纤溶酶原激活物(UPA) 与积极的临床病程、较短的无病生存期有关 在人类乳腺癌中，周期、预后不良和转移增加。更多 最近，HER3和HER4受体的组合配体Hereglin(HRG)， 已被确定为预测预后不良的独立标记物。 近年来，涉及干扰和/或阻止 抗受体单抗对HER介导的自分泌/旁分泌生长的刺激作用 一直是控制乳腺癌生长的积极研究对象 细胞增殖。人源化mAb225(C225)和mAb4D5(Herceptin)是 目前正在进行第二阶段和第三阶段多中心临床试验，包括单独和 与其他抗癌药物联合使用。至于尿激酶，因为 尿激酶型纤溶酶原激活物(UPA)依赖的细胞外激活 蛋白质的降解和侵袭依赖于uPA与其受体的定位， UPAR，阻断这种相互作用也可能导致抑制肿瘤 进展与血管生成。 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 一种特异性uPAR抑制剂(A36)单独或联合应用的临床疗效 联合C225或赫赛汀抑制乳腺癌进展至 更具侵袭性的表型。 我们的工作假说是“自分泌或旁分泌激活 UPA/uPAR系统和/或HRG促进细胞周围侵袭增加 这一途径可能会受到 间充质生长对肿瘤细胞HER2和EGFR的反式激活作用 因子HRG；A36和Herceptin或C225靶向uPA/uPAR可能 抑制乳腺癌的发展。“ 这项建议背后的理由是基于最近所作的观察 由首席调查员和同事提出：(I)HRG--刺激 UPA/uPAR的表达和激活与侵袭；(Ii)特异的uPAR 抑制剂(A36)阻断HRG介导的侵袭；(Iii)A36抑制血管内皮细胞生长因子 激活uPA/uPAR的乳腺癌细胞启动子活性；(Iv)A36 抑制内皮细胞管的形成；(V)C225和Herceptin阻断 EGFR正常表达的浸润性乳腺癌细胞中uPAR的表达 和HER2；以及(Vi)HRG过度表达与短期无病相关 乳腺癌患者的存活率。我们认为HRG，一种间充质细胞 生长因子可能在uPAR对肿瘤的上调中起重要作用 通过为uPA最终激活uPA-uPAR级联而激活细胞 并将uPAR拮抗剂A36与受体拮抗剂结合 在体内，单抗可以增强抗侵袭和抗血管生成的特性/活性。 这项建议的具体目的是：(1)确定分子 HRG及其受体调节uPA/uPAR系统的机制；(2) 检测A36和赫赛汀或C225在临床前的体外和 动物肿瘤转移研究；以及(3)检测uPA/uPAR在 与HRG作为乳腺癌预后因素的关系。独一无二的一面 我们建议的内容之一是描述HRG调节uPA/uPAR的机制 和侵袭性，这将为转移瘤的治疗提供新的理论基础。 人乳腺肿瘤经uPAR抑制剂和抗受体单抗Herceptin或C225治疗。 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.