Cell-by-Cell: Unlocking Lung Cancer Pathogenesis.

Abstract

Simple SummaryAdvances in lung cancer screening have led to a growing need for early intervention strategies for the expanding cohort of patients being diagnosed with the number one cancer killer. Such efforts heavily rely on an in-depth understanding of the pathogenic processes affecting normal lung epithelium and its surrounding microenvironment at the cellular level. More recently, advances in single-cell sequencing approaches have decoded much of the previously elusive complexity of lung malignant processes. Here, we review some of the major contributions of single-cell-based approaches that were employed to enhance our understanding of non-small cell lung cancers, and more specifically, lung adenocarcinomas. We focus on how studying lung adenocarcinomas at a cell-by-cell level continues to unravel an unbeknownst level of intratumor heterogeneity, identify plastic cell states at the heart of tumor inception, and elucidate the complex biology of premalignant progression, thus guiding novel approaches for clinical management of this deadly disease.For lung cancers, cellular trajectories and fates are strongly pruned by cell intrinsic and extrinsic factors. Over the past couple of decades, the combination of comprehensive molecular and genomic approaches, as well as the use of relevant pre-clinical models, enhanced micro-dissection techniques, profiling of rare preneoplastic lesions and surrounding tissues, as well as multi-region tumor sequencing, have all provided in-depth insights into the early biology and evolution of lung cancers. The advent of single-cell sequencing technologies has revolutionized our ability to interrogate these same models, tissues, and cohorts at an unprecedented resolution. Single-cell tracking of lung cancer pathogenesis is now transforming our understanding of the roles and consequences of epithelial-microenvironmental cues and crosstalk during disease evolution. By focusing on non-small lung cancers, specifically lung adenocarcinoma subtype, this review aims to summarize our knowledge base of tumor cells-of-origin and tumor–immune dynamics that have been primarily fueled by single-cell analysis of lung adenocarcinoma specimens at various stages of disease pathogenesis and of relevant animal models. The review will provide an overview of how recent reports are rewriting the mechanistic details of lineage plasticity and intra-tumor heterogeneity at a magnified scale thanks to single-cell studies of early- to late-stage lung adenocarcinomas. Future advances in single-cell technologies, coupled with analysis of minute amounts of rare clinical tissues and novel animal models, are anticipated to help transform our understanding of how diverse micro-events elicit macro-scale consequences, and thus to significantly advance how basic genomic and molecular knowledge of lung cancer evolution can be translated into successful targets for early detection and prevention of this lethal disease.