Tumor-associated macrophages promote the proliferation, invasion and vasculogenic mimicry of Ewing sarcoma cells / 肿瘤

ABSTRACT

Objective: To investigate the effects of tumor-associated macrophages on the proliferation, invasion and vasculogenic mimicry of Ewing sarcoma cells, and to explore the involved molecular mechanism. Methods: Human monocytic U937 cells were cultured and induced to differentiate into M2-type macrophages in vitro. The expressions of M2-type macrophages-relative cytokines such as CD68, CD163 and CD206 in U937 cells before and after induction were detected by realtime fluorescent quantitative PCR. Ewing sarcoma A673 and SK-ES-1 cells were co-cultured with the induced U937 cells (macrophages). Then the effects of co-culture with macrophages on the proliferation, invasion and vasculogenic mimicry of Ewing sarcoma cells were performed using CCK-8, Transwell chamber invasion and matrigel tubule formation assays, respectively. The expressions of signal transducer and activator of transcription 3 (STAT3) and its downstream phospho-STAT3 (p-STAT3), matrix metalloproteinase 2 (MMP2) and cyclin D2 (CCND2) in Ewing sarcoma cells co-cultured with macrophages were detected by Western blotting. Results: The expression levels of CD68, CD163 and CD206 in monocytic U937 cells were significantly up-regulated after induction in vitro (all P < 0.01), suggesting that the human monocytic U937 cells were differentiated into M2-type macrophages. After the M2-type macrophages were co-cultured with Ewing sarcoma A673 and SK-ES-1 cells for 48 h, the proliferation ability of A673 and SK-ES-1 cells increased significantly as compared with the un-co-cultured control group (both P < 0.05), the number of A673 and SK-ES-1 cells passing through matrigel increased significantly as compared with the control group (both P < 0.05), the branches of new vascular in co-cultured groups were more than those in control group (both P < 0.05), and the expression levels of STAT3 and its down-stream p-STAT3, CCND2 and MMP2 proteins were up-regulated in A673 and SK-ES-1 cells (all P < 0.01). Conclusion: Co-culturing with tumor-associated macrophages can induce the proliferation, invasion and vascular mimetic formation of Ewing sarcoma cells, which may be mediated by activating the STAT3 signaling pathway in Ewing sarcoma cells.