We performed this research to investigate the impact of macrophage-derived exosomal miR-503-3p in biological processes of BC cells, and it was found that the downregulation of exosomal miR-503-3p restrained glycolysis and promoted mitochondrial OXPHOS in BC cells via upregulating DACT2 and inhibiting the Wnt/β-catenin signaling pathway. Here, DACT2 is linked to breast cancer.