Abstract
Exosomes carrying microRNAs (miRNAs) mediate cell-to-cell communication, which play important roles in cancer growth and progression. However, the roles and molecular mechanisms of the miRNAs in the exosomes from carcinoma-associated fibroblasts (CAFs) are still not clear. The miRNA array showed that miR-3613-3p was an upregulated miRNA in CAFs exosomes. It was verified that miR-3613-3p was upregulated in exosomes from fibroblasts educated by TGF-β1 and the fibroblasts from breast cancer tissues. Exosomal miR-3613-3p promoted breast cancer cell proliferation and metastasis. The cellular functions showed that miR-3613-3p downregulation in the CAFs exosomes suppressed cell proliferation and metastasis in breast cancer by targeting SOCS2 expression. The clinical data showed that miR-3613-3p levels were negatively related to SOCS2 expression in breast cancer tissues. In a conclusion, the study demonstrated that activated fibroblasts exosomes with high levels of miR-3613-3p played an oncogenic role in breast cancer cell survival and metastasis, which suggested that miR-3613-3p function as a therapeutic target.