Cisplatin treatment induces a shift toward a quiescent Ki-67⁻/CD44⁺/CD133⁺ cancer stem cell subpopulation in a tumorsphere model derived from a murine non-small cell lung cancer cell line.

Non-small cell lung cancer (NSCLC) exhibits substantial cellular and molecular heterogeneity, partly due to the presence of cancer stem cells (CSCs). CSCs can arise from a coordinated process known as epithelial-mesenchymal transition (EMT). EMT promotes a more aggressive phenotype, contributing significantly to tumor heterogeneity and drug resistance. Here, using state-of-the-art techniques-including confocal microscopy, flow cytometry, and transcript analysis-we investigated the cisplatin response of the LL/2 (LLC1) cell line cultured in both monolayer and tumorsphere (3D) models. Strikingly, LL/2 (LLC1) tumorspheres represent a model of cisplatin resistance, showing a remarkable increase in EMT and pluripotency mRNA regulators such as Zeb1, Zeb2, Snail, Twist, Tgfb1, Vimentin, FoxA2, Nanog, and Pou5f1 (Oct-4). Moreover, pseudotime trajectory analysis demonstrated that cisplatin treatment modulates a CSC-like phenotype differently in cells grown as monolayer versus tumorsphere. Our findings provide important insights into the role of cisplatin in NSCLC and highlight potential targets within the lung cancer microenvironment.