FTIR spectra signatures reveal different cellular effects of EGFR inhibitors on nonsmall cell lung cancer cells.

ATP-analogue inhibitors, Gefitinib (Iressa) and Erlotinib (Tarceva) had been approved for advanced and metastatic nonsmall cell lung cancer (NSCLC) cells against tyrosine kinase domain of epidermal growth factor receptor (EGFR). Many techniques have been developed to better understand the drug mechanism which is multistep, time-consuming and expensive. Herein, we performed Fourier-transform infrared (FTIR) microscopy for evaluating the biochemical change on NSCLC (A549) cells after treatment. At levels that produced equivalent effects, Gefitinib dramatically induced cell apoptosis via impaired mitochondrial transmembrane potential. Whereas, Erlotinib had a slight effect on A549. Principal component analysis was performed to distinguish the effect of EGFR inhibitors on A549. FTIR spectra regions were divided into three regions: lipids (3000-2800 cm ), proteins (1700-1500 cm ) and carbohydrates and nuclei acids (1200-1000 cm ). Biochemical changes can be evaluated by these spectral regions. This work may be a novel concept for utilizing FTIR spectroscopy for high-throughput discriminative effects of a drug or compound and its derivatives on cells.