Tumor-associated macrophages promote prostate cancer migration through activation of the CCL22–CCR4 axis

Previous studies have found that tumor-associated macrophages (TAMs) promote cancer progression. We previously reported that TAMs promote prostate cancer metastasis via activation of the CCL2–CCR2 axis. The CCR4 (receptor of CCL17 and CCL22) expression level in breast cancer was reported to be associated with lung metastasis. The aim of this study was to elucidate the role of CCR2 and CCR4 in prostate cancer progression. CCR2 and CCR4 were expressed in human prostate cancer cell lines and prostate cancer tissues. In vitro co-culture of prostate cancer cells and macrophages resulted in increased CCL2 and CCR2 levels in prostate cancer cells. The addition of CCL2 induced CCL22 and CCR4 production in prostate cancer cells. The migration and invasion of prostate cancer cells via enhanced phosphorylation of Akt were promoted by CCL17 and CCL22. CCR4 may be a potential candidate for molecular-targeted therapy.