Investigating EMT-mediated resistance to EGFR tyrosine kinase inhibitors in NSCLC using innovative organoid models

Background Epithelial-mesenchymal transition (EMT) has emerged as a key mechanism underlying resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC). However, the intricacies of EMT-mediated resistance, driven by tumor microenvironment (TME) interactions, remain enigmatic. This study aimed to probe EMT-induced resistance in NSCLC using innovative in vitro organoid models. Methods We generated organoids by co-culturing EGFR-mutant NSCLC cells (HCC827, H1975), mesenchymal stem cells and endothelial cells. Drug susceptibility was compared between organoids and spheroids (cancer cells only) using EGFR TKIs - Gefitinib, Afatinib, Osimertinib. EMT marker (E-cadherin, ZEB1) expression was analyzed via immunofluorescence and western blotting. The effects of Bevacizumab and miR200c on overcoming resistance were also investigated. Results The study identified a significant link between EMT and EGFR-TKI resistance. Notable findings included the decrease of E-cadherin and an increase in ZEB1, both of which influenced EMT and resistance to treatment. Bevacizumab showed promise in improving drug resistance and mitigating EMT, suggesting an involvement of the VEGF cascade. Transfection with miR200c was associated with improved EMT and drug resistance, further highlighting the role of EMT in TKI resistance. Conclusions This study offered vital insights into EMT-driven EGFR TKI resistance, highlighting the utility of organoid models in evaluating resistance modulated by TME interactions. Our findings reveal promising directions for overcoming EMT-mediated resistance involving Bevacizumab and miR200c, warranting further in vivo validation.