Chromosomal instability as a driver of non-small cell lung cancer immune evasion and brain metastasis

项目总结/摘要 脑转移瘤（BM）通常由非小细胞肺癌（NSCLC）引起，是肺癌中最常见的转移瘤。 在美国，BM是癌症相关死亡的常见原因，但我们对BM生物学的理解是基本的。我们集团 最近发现过度的染色体不稳定性（CIN）是BM 19的标志。在体外研究中， 除了在多个独立NSCLC患者数据集（TCGA、GENIE、CCLE和CPTAC）中进行验证外 在本提案中详细说明，我们已经将CIN确定为携带STK 11突变的NSCLC的标志 （编码LKB 1）。LKB 1缺陷型NSCLC是一种侵袭性肿瘤亚型， BM和免疫疗法抗性，因此作为一种相关的原型疾病，可以广泛地告知 CIN在BM生物学和癌症免疫逃避中的作用。CIN是由染色体错误引起的 有丝分裂过程中的分离，导致染色体臂的永久获得和丢失， 易破裂微核。破裂后，这些微核将DNA暴露于胞质溶胶，激活cGAS-STING 发信号。这似乎给CINhigh癌症带来了一个难题，因为cGAS的原型输出- STING活化促进抗肿瘤I型干扰素（IFN）应答。然而，最近的研究表明， CINhigh肿瘤的慢性cGAS-STING信号传导特征促进转移性非经典NF-kB， 输出，除了在肿瘤微环境中产生免疫逃避腺苷外，后者 通过cGAMP输出的适应性增加和表面外核苷酸酶的上调来实现 ENPP 1和NT 5E。除了促进免疫抑制的能力之外，腺苷还使免疫抑制剂渗透化。 血脑屏障，因此可能潜在地将BM与CIN机械地联系起来。这一建议旨在了解 癌细胞如何适应CIN使BM和免疫逃避，即通过研究滋补品 cGAS-STING信号传导的激活。在目标1中，我建议描述CIN和 LKB 1本身丧失转移行为和体内免疫疗法抗性。在目标2中，我将执行空间- 时间分辨的体内研究来描绘CIN-内在的（即，- 外源性（例如腺苷 代）相互作用，使免疫逃避和BM。通过遗传扰动的产生， LKB 1缺陷和WT模型，我将研究慢性cGAMP触发的STING再循环是否是一个潜在的问题。 CIN高的标志，LKB 1缺陷型NSCLC，有利于免疫逃避性肿瘤行为和BM的建立。 总之，这些目标提供了无与伦比的相互作用的研究，这些相互作用对于建立脑转移瘤至关重要。 利基，并将铺平道路的治疗发展的恶性，治疗耐药CINhigh肿瘤。与 杰出导师和合作者的指导，以及无与伦比的科学研究 在哥伦比亚大学欧文医学中心的环境中，这个项目将为我成功的职业生涯做好准备 作为一个癌症生物学领域的医生兼科学家。

PROJECT SUMMARY/ABSTRACT Brain metastasis (BM) frequently arises from non-small cell lung cancer (NSCLC) and represents the most common cause of cancer related death in the US, yet our understanding of BM biology is rudimentary. Our group has recently identified excessive chromosomal instability (CIN) as a hallmark of BM19. In in vitro studies, in addition to validation in multiple independent NSCLC patient datasets (TCGA, GENIE, CCLE, and CPTAC) detailed in this proposal, we have identified CIN as a hallmark of NSCLCs harboring mutations in STK11 (encoding LKB1). LKB1-deficient NSCLCs are an aggressive tumor subtype associated with increased risk of BM and immunotherapy resistance, and thus serves as a relevant archetypical disease that may broadly inform the role of CIN in BM biology and cancer immune evasion. CIN arises from failures in correct chromosome segregation during mitosis, leading to perpetual gains and losses of chromosome arms and the creation of rupture-prone micronuclei. Upon rupture, these micronuclei expose DNA to the cytosol, activating cGAS-STING signaling. This would seemingly present a conundrum for CINhigh cancers, as prototypical outputs of cGAS- STING activation promote anti-tumor type I interferon (IFN) responses. However, it has been recently shown that chronic cGAS-STING signaling characteristic of CINhigh tumors promotes metastatic non-canonical NF-kB output, in addition to immune-evasive adenosine generation in the tumor microenvironment, the latter accomplished through adaptive increases in cGAMP export and upregulation of surface ectonucleotidases ENPP1 and NT5E. In addition to its ability to promote immunosuppression, adenosine also permeabilizes the blood brain barrier and thus may potentially mechanistically link BM to CIN. This proposal seeks to understand how cancer cell adaptations to CIN enable BM and immune evasion, namely through investigation of tonic activation of cGAS-STING signaling. In Aim 1, I propose to delineate the respective contributions of CIN and LKB1 loss per se to metastatic behavior and immunotherapy resistance in vivo. In Aim 2, I will perform spatio- temporal resolved in vivo studies to delineate CIN-intrinsic (i.e., STING signaling) and -extrinsic (e.g. adenosine generation) interactions that enable immune evasion and BM. Through generation of genetic perturbations in LKB1-deficient and WT models, I will investigate whether chronic cGAMP-triggered STING recycling is a hallmark of CINhigh, LKB1-deficient NSCLC that favors immune-evasive tumor behavior and establishment of BM. Together, these aims offer unparalleled study of interactions critical for the establishment of the brain metastatic niche and will pave the way for therapeutic development of malignant, treatment-resistant CINhigh tumors. With the guidance from exceptional mentors and collaborators and access to the unparalleled scientific research environment at Columbia University Irving Medical Center, this project will prepare me for a successful career as a physician-scientist in the field of cancer biology.