ATR-FTIR Spectroscopy and Chemometric Analysis to Characterize Drug-Responsive and Drug-Resistant Human Non-Small Cell Lung Cancer Cells

<jats:p>Osimertinib (Osi) resistance is a pressing challenge in the research for new therapeutic strategies for Epidermal Growth Factor Receptor (EGFR) mutant Non-Small Cell Lung Cancer (NSCLC). This study proposes a novel analytical strategy based on FTIR spectroscopy integrated with chemometric analyses to characterize the biochemical alterations associated with Osi resistance in whole-cells and their fractions after lysis (cytosolic high- and low- MW compounds, as well as pellets). To better visualize spectral variability between Osi resistant cells and their sensitive parental counterparts, a linear principal component analysis was conducted. Spectroscopic analysis identified distinct markers in lipid, protein, and nucleic acid bands, specifically highlighting a significant intensity increase in ester-related vibrations (~1736-1720 cm-1) in the resistant phenotype. These findings, correlated with transcriptomic profiling and mitochondrial gene expression data, demonstrate that FTIR spectroscopy provides a rapid, high-throughput, and robust platform for identifying spectroscopic biomarkers of drug resistance. This approach offers a fast, high-throughput method to detect specific spectroscopic markers, and potentially enables longitudinal monitoring of resistance development over time in cell culture models and in a clinical setting.</jats:p>