M2 macrophages contribute to cell proliferation and migration of breast cancer

Breast cancer is a kind of malignant tumor that severely threatens women's lives and health worldwide. Tumor-associated macrophages (TAMs) have been reported to mediate tumor progression, while the mechanism still needs further identification. In this study, we found that M2 macrophages promoted increased cell proliferation and migration as well as reduced expression of interferon regulatory factor 7 (IRF7) and increased the expression of miR-1587 in breast cancer cells. Overexpression of IRF7 or miR-1587 knockdown reversed M2 macrophage-induced cell proliferation and migration as well as tumor growth in vivo. Mechanistically, miR-1587 targeted the 3MODIFIER LETTER PRIME-untranslated region (3MODIFIER LETTER PRIME-UTR) of IRF7 mRNA to regulate its protein expression leading to tumor progression. Collectively, this study revealed that the miR-1587/IRF7 axis mediates M2 macrophage-induced breast cancer progression, and this sheds light on further clinical therapy for breast cancer by targeting TAMs as well as the miR-1587/IRF7 axis.