PIEZO1 marks a low neuroendocrine state and supports cisplatin tolerance in small cell lung cancer

Small cell lung cancer (SCLC) is initially sensitive to platinum chemotherapy, yet resistant disease frequently develops with altered neuroendocrine (NE) identity. The mechanisms linking these cell states to treatment tolerance remain incompletely understood. Here, we integrate chemoresistant cell models with patient bulk multiomics, single-cell and spatial transcriptomic data to investigate the mechanosensitive channel PIEZO1. In H69AR cells, PIEZO1 upregulation accompanied loss of NE markers and enrichment of mesenchymal programmes; increased PIEZO1 expression and reduced cisplatin sensitivity were also observed in H446DDP cells. Across patient-derived data sources, PIEZO1 was associated with low NE activity within malignant populations, despite its substantially higher abundance in vascular and stromal cells. State-blind CNV analyses and cross-sectional state ordering supported a cell-state association that was only weakly explained by detectable subclones and varied with hypoxia across models. Spatial analyses localized PIEZO1-rich signals to stromal and vascular interface regions, while composition-adjusted tumour-core analyses showed little residual covariance with tumour programmes. PIEZO1 depletion reduced intracellular calcium-associated signals and cisplatin IC50 and increased drug-induced apoptosis. Conversely, Yoda1 increased calcium signals and cisplatin tolerance in parental cells. Patient light-chain phosphorylation, YAP localization and partial pharmacological reversal by verteporfin supported an actomyosin-YAP-linked mechanism. PIEZO1 depletion also reduced SMAD2/3 and mesenchymal-associated readouts. Finally, transcript enrichment profiles and PIEZO1-IGF2BP2 covariation nominated a potential m6A regulatory layer. Together, these findings identify PIEZO1 as a low-NE state-associated marker and contributor to cisplatin tolerance, and motivate a calcium-cytoskeleton-YAP model for further mechanistic testing.