EMT Induction In Normal Breast Epithelial Cells By COX2-Expressing Fibroblasts

BackgroundThe tumor microenvironment (TME) plays a pivotal role in cancer progression, with cancer-associated fibroblasts (CAFs) significantly influencing tumor behavior. Especially, elevated COX2 expressing fibroblasts within the TME, notably in collagen-dense tumors like breast cancer, has been recently emphasized in the literature. However, the specific effect of COX2-expressing CAFs (COX2+ CAFs) on neighboring cells and their consequent role in cancer progression is not fully elucidated. MethodsWe induced COX2+ fibroblasts by forcing the fibroblasts forming aggregates to undergo Nemosis as a proxy for COX2+ CAFs. This approach enabled us to simulate the paracrine interactions between COX2+ CAFs and normal breast epithelial cells via conditioned media from COX2+ fibroblasts. We developed an innovative in vitro platform that combines cell mechanics-based analysis and biomolecular assays to study the interactions between COX2+ fibroblasts and normal breast epithelial cells. By focusing on the mechanical characteristics of the cells and the EMT marker expressions, we aimed to elucidate the paracrine mechanisms through which COX2+ CAFs influence the tumor microenvironment. ResultsOur in vitro findings reveal that COX2+ fibroblasts, through conditioned media, induce significant changes in the mechanical behavior of normal breast epithelial cells, facilitating their transition towards mesenchymal types. This transition was corroborated by increased expression of mesenchymal markers. By drawing parallels between COX2+ fibroblasts and COX2+ CAFs, we established a positive feedback loop involving COX2+ CAFs, prostaglandin E2 (PGE2), and the EP4-SNAI1 axes. ConclusionThis study advances our understanding of the potential mechanisms by which COX2+ CAFs influence tumor progression within the breast tumor microenvironment (TME) through controlled in vitro investigations. By integrating cell mechanics-based analysis, biomolecular assays, and innovative in vitro cell-based modeling of COX2+ CAFs, we have delineated the contributory role of these cells in a controlled setting. These insights lay a groundwork for future studies that could explore the implications of these findings in vivo, potentially guiding targeted therapeutic strategies.