Investigating and targeting metabolic vulnerabilities of MYC-driven small cell lung cancer

项目摘要 小细胞肺癌(SCLC)是一种致命性的神经内分泌肺癌，其治疗具有挑战性。 早期转移，生长迅速，缺乏易于靶向的驱动因素改变。在过去的40年里，SCLC 在临床上主要作为单一疾病与以铂为基础的联合化疗进行治疗 中位生存期仅为约10-12个月。必须更好地了解小细胞肺癌生物学，才能 开发新的治疗策略，有效地延长患者的生存时间。小细胞肺癌肿瘤放大或 过表达一个致癌的MYC家族成员：MYC、MYCL或MYCN。MYC-高SCLC在代谢过程中 不同于MYC-LOW，具有特定和有针对性的代谢脆弱性。最有效的治疗方法 临床前试验中治疗MYC高SCLC的策略是聚乙二醇化去循环精氨酸 精氨酸脱亚胺酶(ADI-PEG20)。高MYC的SCLC对ADI-PEG20特别敏感，因为它们缺乏 精氨酸琥珀酸合成酶1(ASS1)催化尿素从头合成精氨酸 周而复始。尽管如此，小细胞肺癌最终对ADI-PEG20(ADIR)产生耐药，这与Re-PEG20相对应。 ASS1的表达。在ADIR后，肿瘤获得可能被靶向的次级代谢依赖 延长ADI-PEG20反应和患者生存时间。初步数据显示ADIR SCLC依赖丝氨酸 和一碳(1C)代谢，这可以作为抗叶酸的靶点。初步数据还描绘了 候选转录调控因子可能在小细胞肺癌中调控ADIR。激活转录因子4(ATF4)， 逆境反应转录因子，是富含ADIR的基因程序的上游调控因子 VS幼稚的SCLC-通过散装和单细胞RNA测序确定。急性精氨酸诱导的血管紧张素转换酶4 在小细胞肺癌中被剥夺，并且在ADIR期间继续与其靶基因一起表达。在这里，申请者将 采用单细胞RNA序列衍生的小细胞肺癌对ADI-PEG20的反应模型，体内代谢物分析 同位素追踪，以及基于CRISPR的基因编辑，以询问ATF4是否统治ADIR。假设 这项研究表明，ATF4通过促进ASS1依赖的丝氨酸和1C代谢来驱动ADIR。 实验将在两个特定的目标下进行，以测试ATF4是否支配：1)MYC-HIGH的敏感性 SCLC对ADI-PEG20的敏感性，和/或2)ADIR SCLC对1C代谢抑制剂的敏感性。收集到的知识 从这项研究将提供联合治疗策略，以提高ADI-PEG20和 延长小细胞肺癌和其他ASS1-低肿瘤患者的生存期。拟议的研究将提供独特的 申请人有机会获得癌症生物学、癌症新陈代谢和计算机方面的专业知识 分析--组学数据--申请人培训计划的三个主要目标。拟议的研究将会进行 在亨斯迈癌症研究所和犹他大学接受了三年多的培训，合作和 资源丰富的培训环境，在特鲁迪·奥利弗博士的实验室里。

PROJECT ABSTRACT Small cell lung cancer (SCLC) is a fatal neuroendocrine lung tumor that is challenging to treat due to early metastasis, rapid growth, and a lack of easily targetable driver alterations. For the last ~40 years, SCLC has been treated primarily as a single disease in the clinic with combination, platinum-based chemotherapy that offers a median survival of only ~10-12 months. It is imperative to better understand SCLC biology to enable development of novel treatment strategies that effectively prolong patient survival. SCLC tumors amplify or overexpress one oncogenic MYC family member: MYC, MYCL, or MYCN. MYC-high SCLCs are metabolically distinct from MYC-low, and have specific and targetable metabolic vulnerabilities. The most effective therapeutic strategy for treatment of MYC-high SCLCs in preclinical trials is deprivation of circulating arginine by pegylated arginine deiminase (ADI-PEG20). MYC-high SCLCs are particularly sensitive to ADI-PEG20, because they lack the enzyme argininosuccinate synthetase 1 (ASS1) that catalyzes de novo synthesis of arginine by the urea cycle. Still, SCLC tumors eventually develop resistance to ADI-PEG20 (ADIR) that corresponds with re- expression of ASS1. Upon ADIR, tumors acquire secondary metabolic dependencies that may be targeted to prolong ADI-PEG20 response and patient survival. Preliminary data show that ADIR SCLC depends on serine and one-carbon (1C) metabolism, which can be targeted with anti-folates. Preliminary data also delineate candidate transcriptional regulators that may govern ADIR in SCLC. Activating transcription factor 4 (ATF4), a stress-responsive transcription factor, is one predicted upstream regulator of gene programs enriched in ADIR vs naïve SCLCs—determined by bulk and single-cell RNA sequencing. ATF4 is induced upon acute arginine deprivation in SCLC and continues to be expressed with its target genes during ADIR. Here, the applicant will employ a single-cell RNA-seq-derived model of SCLC response to ADI-PEG20, metabolite profiling, in vivo isotope tracing, and CRISPR-based gene editing to interrogate whether ATF4 governs ADIR. The hypothesis for this research is that ATF4 drives ADIR by enhancing serine and 1C metabolism in an ASS1-dependent manner. Experiments will be performed in two specific aims to test whether ATF4 governs: 1) the sensitivity of MYC-high SCLCs to ADI-PEG20, and/or 2) the sensitivity of ADIR SCLCs to 1C metabolism inhibitors. Knowledge gleaned from this research will inform combination treatment strategies that improve the efficacy of ADI-PEG20 and extend survival of patients with SCLC and other ASS1-low tumors. The proposed research will provide unique opportunities for the applicant to gain expertise in cancer biology, cancer metabolism, and computational analysis of -omics data—three major goals of the applicant’s training plan. The proposed research will occur over three years of training at Huntsman Cancer Institute and the University of Utah, a collaborative and resource-rich training environment, in the lab of Dr. Trudy Oliver.