Exosomal miR-222 from adriamycin-resistant MCF-7 breast cancer cells promote macrophages M2 polarization via PTEN/Akt to induce tumor progression

. Collectively, our data demonstrated that chemoresistant BCa cells could remodel macrophages within tumor microenvironment by secreting exosomal miR-222, which directly targeted PTEN and caused Akt cascade activation and macrophages M2 polarization. Our findings may provide a foundation for a promising strategy of BCa treatment by targeting exosomes or exosomal miR-222.