Elevating microRNA-1-3p shuttled by cancer-associated fibroblasts-derived extracellular vesicles suppresses breast cancer progression and metastasis by inhibiting GLIS1.

Cancer-associated fibroblasts (CAFs) play supporting roles in tumor progression by releasing microvesicles that transmit oncogenic cargoes. Indeed, extracellular vesicles (EVs) have emerged as important vehicles to deliver proteins, messenger RNAs (mRNAs), and microRNAs (miRs) between cells. In this study, we aimed to outline the role and function of CAFs-derived EVs carrying miR-1-3p in breast cancer. We first experimentally determined downregulated miR-1-3p in breast cancer tissues. EVs were isolated from CAFs extracted from breast cancer tissues, which showed downregulated miR-1-3p expression relative to EVs derived from normal fibroblasts (NFs). In a co-culture system, miR-1-3p cargo was transported into breast cancer cells via CAF-derived EVs. In gain-of-function experiments, the elevation of miR-1-3p in breast cancer cells inhibited cell viability, invasion, migration, and epithelial-to-mesenchymal transition, and suppressed tumor formation and metastasis. Furthermore, EVs derived from CAFs transfected with miR-1-3p mimic were more effective in transferring miR-1-3p to suppress cancer progression and metastasis. Krüppel-like zinc-finger protein Gli-similar 1 (GLIS1) was predicted to be a putative target of miR-1-3p, which was subsequently confirmed by dual-luciferase reporter assay. We then demonstrated that overexpression of GLIS1 neutralized the effects of miR-1-3 on the development of breast cancer in vitro. These findings shed light on the underlying mechanism by which CAFs-derived EVs carrying miR-1-3p mediate the progression and metastasis of breast cancer, and highlight the potential of miR-1-3p shuttled by CAFs-derived EVs serving as a therapeutic target for breast cancer.