Novel RTK Targeting Strategies in Glioblastoma

描述（由申请人提供）：受体酪氨酸激酶（RTK）通路在大多数胶质母细胞瘤（GBM）（最常见和最致命的原发性恶性脑肿瘤）中失调。因此，已经开发了许多临床上适用的RTK抑制剂。然而，这些抑制剂未能显著改善GBM患者的临床结局。这种失败的主要原因是由于几种RTK的共激活引起的信号冗余和导致对RTK抑制的抗性的补偿机制。在这个竞争性的更新应用中，我们建立在我们以前的研究结果的基础上，并提出探索新的机制和策略，以提高MET和其他RTK抑制剂在GBM治疗中的疗效。更具体地说，我们建议全面揭示决定临床适用药物对MET抑制的敏感性和耐药性的因素，并利用获得的知识来测试新的和更有效的联合疗法。我们还建议探索两种概念上新颖的方法，用于GBM治疗中的RTK靶向，这些方法基于我们实验室最近的两个令人兴奋的发现。我们提出了四个具体目标。在目标1中，我们将确定 确定MET抑制敏感性的不为人所知的因素。我们将使用RNA-seq、反相抗体阵列和PCR来全面鉴定决定GBM细胞、干细胞、动物模型和MetMAb临床试验衍生的人类肿瘤对临床适用的小分子激酶抑制剂（克唑替尼）和MET中和抗体（MetMAb）的反应性的遗传和分子因素。在目标2中，我们将全面阐明上述药物对MET抑制的耐药性机制，并开发克服耐药性的新联合治疗。在目标3中，我们将研究和开发配体预处理作为提高MET、EGFR和PDGFR抑制剂疗效的新策略。这是基于我们实验室最近的一个有趣的发现，该发现表明用各自的配体对RTK进行短期预处理可以增强其抑制剂的抗肿瘤作用。在目标4中，我们将探索microRNA-134（miR- 134）在RTK信号传导和实验治疗中的作用。这是基于我们实验室最近发现的miR-134作为一种新的肿瘤抑制中心，介导RTK在GBM中的作用，并且是其抑制剂的抗肿瘤作用所必需的。对于目标3和4，我们将开发和测试新的临床前 使用聚焦超声和微泡/纳米颗粒以及对流增强递送将RTK配体和microRNA全身和局部递送至GBM异种移植物的方法。总之，成功完成拟议的研究将导致更好地了解MET和RTK诱导的恶性肿瘤的机制，并开发新的和更有效的RTK靶向GBM治疗策略。

DESCRIPTION (provided by applicant): Receptor tyrosine kinase (RTK) pathways are deregulated in a majority of glioblastoma (GBM), the most common and most deadly primary malignant brain tumor. Consequently, a number of clinically applicable RTK inhibitors have been developed. However, these inhibitors failed to significantly improve the clinical outcomes of GBM patients. The main reasons for this failure are signal redundancy due to co-activation of several RTKs and compensatory mechanisms that lead to resistance to RTK inhibition. In this competitive renewal application, we build on our previous findings and propose to explore new mechanisms and strategies for improving the efficacy of MET and other RTK inhibitions in GBM therapy. More specifically, we propose to comprehensively uncover the factors that determine sensitivity and resistance to MET inhibition with clinically applicable drugs and use the acquired knowledge to test new and more efficient combination therapies. We also propose to explore two conceptually novel approaches for RTK targeting in GBM therapy that are based on two recent exciting discoveries from our lab. We propose four specific aims. In Aim 1, we will identify the not well known factors that determine sensitivity to MET inhibition. We will use RNA-seq, reverse phase antibody arrays, and PCR to comprehensively identify the genetic and molecular factors that determine responsiveness to clinically applicable small molecule kinase inhibitor (crizotinib) and MET neutralizing antibody (MetMAb) in GBM cells, stem cells, animal models and MetMAb clinical trial-derived human tumors. In Aim 2, we will comprehensively elucidate the mechanisms of resistance to MET inhibition by the above drugs and develop new combination therapies that overcome resistance. In Aim 3, we will study and develop ligand pre-treatment as a new strategy for improving the efficacy of MET, EGFR and PDGFR inhibitors. This is based on a recent intriguing discovery form our lab that shows that short-term pre-treatment of RTKs with their respective ligands enhances the anti-tumor effects of their inhibitors. In Aim 4, we will explore the role of microRNA-134 (miR- 134) in RTK signaling and experimental therapy. This is based on the recent discovery in our lab of miR-134 as a new tumor suppressive hub that mediates the effects of RTKs in GBM and that is required for the anti-tumor effects of their inhibitors. For Aims 3 and 4, we will develop and test new pre-clinical approaches for the systemic and local deliveries of RTK ligands and microRNAs to GBM xenografts using focused ultrasound and microbubbles/nanoparticles as well as convection enhanced delivery. Altogether, successful completion of the proposed studies would lead to a better understanding of the mechanisms of MET and RTK-induced malignancy and to the development of novel and more efficient RTK targeting strategies for GBM therapy.