Project 3: Identifying and targeting mediators of CNS metastasis from lung cancer

项目总结 肺癌是中枢神经系统(CNS)转移的主要来源。有一个重要的 我们对脑转移瘤对治疗的反应以及维持转移的机制的理解上的差距 中枢神经系统的肿瘤。从历史上看，血脑屏障一直被视为全身药物的障碍， 此外，还开发了新的脑渗透剂，如突变的EGFR抑制剂osimertinib。然而， 尽管这些药物的临床反应有所改善，但脑转移瘤仍在进展，而且尚不清楚是如何发生的。 脑肿瘤微环境(TME)的扰动可用于更有效的治疗 中枢神经系统疾病患者。我们已经开发了新的方法来表征人脑的分子特征 脑脊液(CSF)以及区分脑转移瘤与间质基因改变的活体研究。我们的 方法发现了基因突变和大脑TME诱导的变化，这些变化集中在合作 血管内皮生长因子、Noch、β-catenin和PI3K调控的信号转导通路。我们假设这些 分子改变：1)协同驱动非小细胞肺癌脑转移和脑内耐药，2)是 临床上可操作的，以及3)由于分歧，在人类脑脊液或脑活检中更准确地检测到 遗传进化和TME诱导的脑转移瘤适应。 我们的假设将在三个独立但互补的目标中进行研究。在Aim1中，我们建议收集 人脑脊液来自开颅手术和腰椎穿刺术的肺癌脑转移患者 将接受支气管镜活检。通过比较匹配的脑脊液、血浆的突变情况 和肿瘤组织，我们将从分子上描述人类无症状脑转移的特征。此外，我们 将使用新的原位患者衍生的异种移植模型(PDX)来确定脑转移是否进展 药物反应与在人类脑脊液中发现的共生突变相关。在目标2中，我们将测试 一种新的假说：激活的脑微血管通过以下途径提高耐药肿瘤细胞的存活率 基质诱导体内的缺口信号。我们将评估新的双特异性药物是否同时抑制 血管内皮生长因子和Noch可延缓脑转移进展和/或改善临床前奥西美替尼的疗效 模特们。利用人类生物样本，我们将把血管内皮生长因子的表达与Noch途径联系起来。 有脑转移复发的成分。在目标3中，我们将进行一项结合突变特异性的临床试验。 TKI(奥西美替尼)联合脑血管靶向剂(贝伐单抗)治疗初治肺癌 有EGFR突变的肿瘤和中枢神经系统疾病。最后，分子标记(包括AIMS 1和AIMS中研究的标记 2)将通过分析脑脊液、血浆和肿瘤活检来确定对这种联合治疗的反应或耐药性。 这一提议将有助于揭示脑转移瘤复发的生物学基础。重要的是，我们的研究将 洞察如何利用当前和未来的治疗方法来针对肿瘤特异性 突变和TME，以改善患有中枢神经系统疾病的肺癌患者的临床结果。

PROJECT SUMMARY Lung cancers are the major source of metastasis in the central nervous system (CNS). There is an important gap in our understanding of how brain metastases respond to therapies and what mechanisms sustain metastatic tumors in the CNS. Historically, the blood brain barrier has been viewed as an impediment to systemic drugs, and novel brain penetrant agents such as the mutant EGFR inhibitor osimertinib have been developed. However, despite improved clinical responses with these agents, brain metastases still progress, and it is unknown how perturbations in the brain tumor microenvironment (TME) can be leveraged for more effective treatments in patients with CNS disease. We have developed novel methods to molecularly characterize human cerebral spinal fluid (CSF) as well as distinguish tumor from stromal gene alterations of brain metastasis in vivo. Our approaches uncover genetic mutations as well as brain TME induced alterations that converge onto cooperating pathways, such as those regulated by VEGF, NOTCH, β-catenin and PI3K. We hypothesize that these molecular alterations: 1) cooperatively drive NSCLC brain metastasis and drug resistance in the brain, 2) are clinically actionable, and 3) are more accurately detected in human CSF or brain biopsies, due to divergent genetic evolution and TME induced adaptation of brain metastasis. Our hypothesis will be studied in 3 independent yet complimentary aims. In Aim1, we propose to collect human CSF from craniotomies as well as lumbar punctures of lung cancer patients with brain metastases who will be undergoing a bronchoscopic biopsy. By comparing the mutational landscape of matched CSF, plasma and tumor tissue, we will molecularly characterize humans with asymptomatic brain metastasis. Moreover, we will use novel orthotopic patient derived xenograft models (PDXs) to determine if brain metastasis progression and drug response correlates with co-occurring mutations identified in human CSF. In Aim 2, we will test the novel hypothesis that an activated brain microvasculature enhances the survival of drug resistant tumor cells via stromal induced NOTCH signaling in vivo. We will assess if novel bi-specific agents which simultaneously inhibit VEGF and NOTCH can delay brain metastasis progression and/or improve osimertinib response in pre-clinical models. Using human biospecimens, we will correlate the expression of VEGF and NOTCH pathway components with brain metastatic relapse. In Aim 3, we will conduct a clinical trial combining a mutation specific TKI (osimertinib) with a brain vascular targeting agent (bevacizumab) in treatment naïve lung cancer patients with EGFR mutant tumors and CNS disease. Finally, molecular markers (including those studied in Aims 1 and 2) of response or resistance to this combination will be identified by analyzing CSF, plasma and tumor biopsies. This proposal will help uncover the biological basis of brain metastasis relapse. Importantly, our study will generate insight as to how current and prospective therapies can be harnessed to target both tumor specific mutations and the TME, in a manner that improves clinical outcomes for lung cancer patients with CNS disease.