Abstract
Plasticity-the ability of cells to undergo phenotypic transitions-drives cancer progression and therapy resistance1-3. Recent studies have suggested that plasticity in solid tumours is concentrated in a minority subset of cancer cells4-6, yet functional studies examining this high-plasticity cell state (HPCS) in situ are lacking. Here we develop mouse models enabling the detection, longitudinal lineage tracing and ablation of the HPCS in autochthonous lung tumours in vivo. Lineage tracing reveals that the HPCS cells possess a high capacity for cell state transitions, giving rise to both early neoplastic (differentiated) and progressed lung cancer cell states in situ. Longitudinal lineage tracing using secreted luciferases reveals that HPCS-derived cells have a high capacity for growth compared with bulk cancer cells or another cancer cell state with features of differentiated lung epithelium. Ablation of HPCS cells in early neoplasias abrogates benign-to-malignant transition, whereas ablation in established tumours by suicide gene or chimeric antigen receptor (CAR) T cells robustly reduces tumour burden. We further demonstrate that the HPCS gives rise to therapy-resistant cell states, whereas HPCS ablation suppresses resistance to chemotherapy and oncoprotein-targeted therapy. Notably, an HPCS-like state is ubiquitous in regenerating epithelia and in carcinomas of multiple other tissues, revealing a convergence of plasticity programs. Our work establishes the HPCS as a critical hub enabling reciprocal transitions between cancer cell states. Targeting the HPCS in lung cancer and in other carcinomas may suppress cancer progression and eradicate treatment resistance.