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

项目摘要 肺癌是中枢神经系统（CNS）转移的主要来源。有一个重要 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存在差距 CNS中的肿瘤。从历史上看，血脑屏障一直被视为全身药物的障碍， 并且已经开发了新的脑渗透剂如突变EGFR抑制剂奥希替尼。然而，在这方面， 尽管这些药物改善了临床反应，但脑转移仍在进展，并且尚不清楚如何进展。 脑肿瘤微环境（TME）的扰动可以用于更有效的治疗， CNS疾病患者。我们已经开发了新的方法来分子表征人类大脑 以及在体内区分肿瘤与脑转移瘤间质基因改变。我们 这些方法揭示了基因突变以及大脑TME诱导的改变， 在一些实施方案中，所述方法包括通过诸如由VEGF、NOTCH、β-连环蛋白和PI 3 K调节的那些途径来调节细胞凋亡。我们假设这些 分子改变：1）协同驱动NSCLC脑转移和脑中的耐药性，2） 临床上可操作的，和3）由于不同的生物学特性，在人CSF或脑活检中更准确地检测到， 遗传进化和TME诱导的脑转移适应。 我们的假设将在3个独立但互补的目标中进行研究。在目标1中，我们建议收集 脑转移肺癌患者开颅术和腰椎穿刺的人CSF， 将接受支气管镜活检通过比较匹配的CSF、血浆 和肿瘤组织，我们将从分子上表征无症状脑转移的人。而且我们 将使用新的原位患者来源的异种移植物模型（PDX）来确定脑转移进展 并且药物反应与在人CSF中鉴定的共同发生的突变相关。在目标2中，我们将测试 一种新的假说，即激活的脑微血管通过以下途径增强耐药肿瘤细胞的存活： 基质诱导的体内NOTCH信号传导。我们将评估是否有新的双特异性药物，同时抑制 VEGF和NOTCH可延迟脑转移进展和/或改善临床前奥希替尼反应。 模型使用人类生物标本，我们将VEGF和NOTCH通路的表达关联起来， 脑转移复发的成分。在目标3中，我们将进行一项临床试验， TKI（奥希替尼）联合脑血管靶向药物（贝伐珠单抗）治疗初治肺癌患者 EGFR突变肿瘤和中枢神经系统疾病。最后，分子标记（包括在目的1和 2)通过分析CSF、血浆和肿瘤活组织检查来鉴定对该组合的应答或抗性。 这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 产生关于如何利用当前和未来疗法来靶向肿瘤特异性 突变和TME，以改善患有CNS疾病的肺癌患者的临床结果的方式。

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.