• Breast cancer-derived exosomes, particularly from highly metastatic cells, are endocytosed by fibroblasts and induce their transformation into cancer-associated fibroblasts (CAFs).
• Exosomal miR-105-5p is enriched in highly metastatic breast cancer cells and is sorted into exosomes via RBMY1A1, promoting NF-to-CAF conversion.
• miR-105-5p downregulates LATS2 expression and activates NF-κB signaling, concurrently facilitating epithelial-mesenchymal transition (EMT) of breast cancer cells.
• Targeting exosomal miR-105-5p may offer a novel therapeutic strategy to disrupt the coevolution of breast cancer cells and CAFs in the tumor microenvironment.