Cellular plasticity gives rise to phenotypic equilibrium in small cell lung carcinoma

摘要 小细胞肺癌（SCLC）是最难治愈的人类癌症之一。这是一种侵袭性肿瘤 特征为快速生长、转移进展和初始反应，随后几乎不变 对治疗的抵抗迄今为止的研究还没有解决不同的遗传和表观遗传程序 驱动SCLC并增加其杀伤力。我们将世界上最大、最多样化的 患者来源的SCLC异种移植物模型，其离体培养系统维持了 与匹配的原发性SCLC肿瘤的转录保真度，以鉴定不同的和动态的表型状态， 在个体肿瘤内的功能属性不同。我们发现，人类SCLC肿瘤表现出独特的 在各种表型（不仅仅是转录）状态下细胞比例的平衡。我们也证明了 SCLC状态高度受多价细胞可塑性调节，我们测量了这种可塑性的动力学 在单细胞水平上。重要的是，这种疾病的标准治疗化疗优先杀死特定的 癌细胞状态。在这个建议中，我们认为理解小细胞肺癌瘤内异质性的各个方面， 将：1）有助于我们了解癌症异质性的一个特征不明确的方面; 2）揭示如何 单细胞行为中的随机性和/或生态学线索促进癌症中的表型平衡 人群; 3）提供对SCLC的生物学和临床行为的洞察力;以及4）拼命推进 需要新的治疗策略的表观遗传重编程在这种罕见的疾病。我们的团队的 研究人员在几个计算，实验和翻译方法相关的内容专业知识 包括人源性体内和离体模型系统、单细胞RNA测序、批量测序、 遗传和表达分析、单细胞荧光跟踪以及数学和统计建模。 我们的综合方法准备制定和验证一个统一的模型细胞的状态和程序 SCLC的多样性如果成功，恶性细胞个体发育程序（SA 1）的表征，其可塑性 (SA2)，以及旨在通过表观遗传重编程（SA 3）对抗可塑性的新疗法的进展 将为研究这种高度致命的疾病提供一个独特的科学画布。

ABSTRACT Small cell lung carcinoma (SCLC) is one of the most intractable human cancers to cure. It is an aggressive tumor characterized by rapid growth, metastatic progression, and initial response followed by almost invariable resistance to therapy. Studies to date have not resolved the extent that diverse genetic and epigenetic programs drive SCLC and contribute to its lethality. We combined one of the largest and most diverse inventories of patient-derived xenograft models of SCLC globally with an ex vivo culture system that maintains transcriptional fidelity with matched primary SCLC tumor to identify distinct and dynamic phenotypic states that differ in functional attributes within individual tumors. We show that human SCLC tumors display distinctive equilibria in the proportion of cells in various phenotypic (not merely transcriptional) states. We also show that SCLC states are highly regulated by multivalent cellular plasticity and we measure the kinetics of this plasticity at the single cell level. Importantly, standard of care chemotherapies in this disease preferentially kill specific cancer cell states. In this proposal, we posit that understanding the facets of SCLC's intratumoral heterogeneity will: 1) contribute to our understanding of a poorly characterized aspect of cancer heterogeneity; 2) reveal how stochasticity and/or ecological cues in single-cell behaviors promote phenotypic equilibrium in cancer populations; 3) provide insight into the biological and clinical behavior of SCLC; and 4) advance desperately needed new therapeutic strategies of epigenetic reprogramming in this recalcitrant disease. Our team of investigators have content expertise in several computational, experimental, and translational methods pertinent to this proposal including human-derived in vivo and ex vivo model systems, single-cell RNA sequencing, bulk genetic and expression analysis, single cell fluorescence tracking, and mathematical and statistical modeling. Our integrative approach is poised to formulate and validate a unified model of cellular states and program diversity in SCLC. If successful, the characterization of malignant cell ontogenic programs (SA1), their plasticity (SA2), and the advancement of new therapies designed to combat plasticity by epigenetic reprogramming (SA3) will advance a unique scientific canvas for the study of this highly lethal disease.