Abstract
The epidermal growth factor receptor (EGFR) signaling pathway is essential for cellular processes such as proliferation, survival, and migration. Dysregulation of EGFR signaling is frequently observed in non-small cell lung cancer (NSCLC) and is associated with poor prognosis. This study aims to isolate and characterize extracellular vesicles (EVs) released by mutant EGFR lung cancer cell line PC9 and compare them with wild-type EGFR lung cancer cell line A549, while also evaluating the effect of gefitinib treatment on EV secretion and cargo composition. The two lung cancer cell lines were cultured with 2% EV-free serum, and EVs were subsequently isolated by differential ultra centrifugation. EVs were characterized by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) for quantification size and shape determination. Western blot analysis confirmed the enrichment and purity of isolated EVs. Results showed that EGFR mutation significantly increased EV release and altered their size, compared to EVs released by wild-type EGFR cells. In addition to classical EV markers such as CD81, Flotillin- 1, and TSG101, Western blot analysis also detected phosphorylated EGFR (p-EGFR) selectively packaged into EVs from PC9 cells. Gefitinib treatment significantly reduced EV secretion in PC9 cells and led to a marked decrease in p-EGFR incorporation into EVs, indicating that EV biogenesis and compostion are modulated by active EGFR signaling. In conclusion, this study highlights the significant influence of EGFR activation on EV secretion and cargo composition while demonstrating that EGFR inhibition via gefitinib alters EV-mediated signaling in lung cancer cells. These findings provide insights into tumor behavior, EV-mediated oncogenic communication, and the potential use of EVs as biomarkers and therapeutic targets in NSCLC.