Identification of a human airway epithelial cell subpopulation with altered biophysical, molecular, and metastatic properties

Lung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant pulmonary epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of unselected cells. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8-weeks post-selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short term assays and enhanced outgrowth of premalignant lesions in longer term assays, thus overcoming important aspects of “metastatic inefficiency.” Overall, our findings indicate that among premalignant pulmonary epithelial cells, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior. Six different HBEC cell lines were under selection of highly migratory cells. Bioconductor limma package was utilized for identifying genes differentially expressed between selected and unselected populations.

已有研究证实，肺癌存在显著的肿瘤内遗传异质性。然而，学界对于细胞运动能力等生物物理特性的异质性，及其与肺癌早期发病机制、微转移播散的关联仍知之甚少。本研究中，我们筛选并分离得到一类高迁移性癌前肺上皮细胞亚群：实验观察到，该亚群细胞通过微尺度狭窄结构的迁移速率可达未筛选细胞的最高100倍。研究发现，这种增强的迁移能力依赖于Rac1且具有可遗传性：筛选后超过8周的连续多轮细胞分裂仍可维持该表型，从而证实了这一特性。该肺上皮细胞亚群的形态学特征表现为细胞突起强度显著升高。在微转移定植与肺定植的小鼠模型中，经运动能力筛选的癌前细胞在短期实验中展现出更强的存活能力，在长期实验中则可促进癌前病变的增殖，从而克服了“转移低效性”的多个关键环节。综上，本研究结果表明，在癌前肺上皮细胞中，存在具有可遗传性运动相关生物物理特性的细胞亚群，这一发现或可解释肺癌发病早期阶段发生的微转移定植现象。针对这些关键生物物理特性及其潜在分子机制进行解析、干预与预防，或可为阻断肿瘤转移行为提供全新的治疗策略。本研究共使用6株不同的人支气管上皮细胞（HBEC, Human Bronchial Epithelial Cells）系进行高迁移性细胞的筛选。本研究使用Bioconductor的limma软件包，对筛选与未筛选细胞群体间的差异表达基因进行鉴定。