Tumor-associated macrophages (TAMs) are important monocytes in the breast cancer microenvironment. They facilitate the distant metastasis of breast cancer. However, the detailed mechanisms of TAM-derived cancer metastasis have not been clearly elucidated. Here, we demonstrate that PRMT1 is essential for TAM-mediated breast cancer cell migration and metastasis. TAMs increase EZH2 stability by stimulating PRMT1-mediated meR342-EZH2 formation through the secretion of interleukin-6 (IL-6) cytokine. Moreover, high expression levels of TAMs are positively correlated with PRMT1, meR342-EZH2, and EZH2 expression in breast cancer patients. Our study presents a novel mechanism of TAM-induced breast cancer metastasis via the IL-6-PRMT1-meR342-EZH2 axis.

肿瘤相关巨噬细胞（TAM）是乳腺癌微环境中重要的单核细胞。它们促进了乳腺癌的远处转移。但是，尚未清楚阐明TAM衍生的癌症转移的详细机制。在这里，我们证明PRMT1对于TAM介导的乳腺癌细胞迁移和转移至关重要。TAM通过分泌白介素6（IL-6）细胞因子刺激PRMT1介导的meR342-EZH2形成，从而提高EZH2稳定性。此外，乳腺癌患者中TAM的高表达水平与PRMT1，meR342-EZH2和EZH2表达正相关。我们的研究通过IL-6-PRMT1-meR342-EZH2轴提出了TAM诱导的乳腺癌转移的新机制。