CCL2 is a member of the CC chemokine superfamily that plays a crucial role in mediating macrophage recruitment and prostate cancer (PCa) metastasis. We have discovered that inhibiting the function of androgen receptor (AR) in prostate cancer cells results in the upregulation CCL2 and promotes disease progression by recruiting macrophages, activating signal transducer and activator of transcription 3 (STAT3), and by favoring the epithelial-to-mesenchymal transition. However, the molecular switches controlling CCL2 downstream signaling in PCa cells are not well understood. Here, we established an in vitro cell migration screening system using transwell migration chambers, and identified a higher amount of CCL2 in migrating PCa cells, establishing a link between CCL2 and a subpopulation of PCa cells. Importantly, we found that CCL2 expression correlated with the EMT marker, N-cadherin in migrating PCa cells. Importantly, CCL2 stimulation in PCa cells enhanced the expression levels of several EMT markers and induced STAT3 activation. In addition, CCL2 stimulation in PCa cells induced the downregulation of dual-specificity phosphatase 22 (DUSP22), which has been shown to act as a negative regulator of the IL-6-induced STAT3 activation through a direct interaction with STAT3. This supports that CCL2-induced DUSP22 downregulation in PCa cells as a potential mechanism to promote EMT. Therefore, we believe CCL2 may promote PCa metastasis in an autocrine manner through promotion of EMT in PCa cells with more aggressive motility behaviors. Targeting of the CCL2-STAT3 axis may offer new approaches to suppress the multifaceted support (immunosuppression, macrophage recruitment, and angiogenesis) of CCL2 for PCa cells in complex tumor microenvironment.
Citation Format: Wen-Jye Lin, Kouji Izumi, Showping Lin, Hui-Min Ho. CCL2 promotes epithelial-mesenchymal transition (EMT) in prostate cancer cells via downregulation of dual-specificity phosphatase 22. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr B75.
- ©2015 American Association for Cancer Research.