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. ### Competing Interest Statement The authors have declared no competing interest. * Bev : Bevacizumab - A monoclonal antibody that can interrupt vascular growth by binding to vascular endothelial growth factor. CAFs : Cancer-associated fibroblasts - Cells within the tumor microenvironment that promote tumorigenesis. EGFR : Epidermal Growth Factor Receptor - A protein present on certain cell surfaces where epidermal growth factor binds, causing the cells to divide. EMT : Epithelial-Mesenchymal Transition - A process whereby epithelial cells lose cell polarity and cell-cell adhesion, and gain migratory and invasive properties. HUVECs : Human Umbilical Vein Endothelial Cells - Cells derived from the endothelium of veins from the umbilical cord. MSCs : Mesenchymal Stem Cells - Multipotent stromal cells that can differentiate into a variety of cell types. NSCLC : Non-small Cell Lung Cancer - The most common type of lung cancer. TME : Tumor Microenvironment - The environment around a tumor, including the surrounding blood vessels, immune cells, fibroblasts, signaling molecules and the extracellular matrix. TKIs : Tyrosine Kinase Inhibitors - A type of drug that inhibits tyrosine kinases, enzymes responsible for the activation of many proteins by signal transduction cascades. VEGF : Vascular Endothelial Growth Factor - A signal protein produced by cells that stimulates the formation of blood vessels