N-glycan-defective breast cancer cells induce a phenotypic switch in polarization of bone marrow-derived macrophages.

Purpose: To investigate the effect of N-glycan-defective mammary adenocarcinoma cells on the polarization of macrophages. Methods: N-glycan-defective breast cancer cells (MA782 cells) were prepared by swainsonine (SW) treatment and the cytotoxicity of SW to MA782 cells was evaluated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The N-glycan-defective MA782 cells were co-cultured with bone marrow-derived macrophages (BMDMs) for 48 h in vitro, and then the BMDMs and the co-cultured supernatant were analyzed for macrophage phenotypic using FQRT-PCR, FCM and ELISA. Results: SW-treated MA782 cells expressed defective N-glycan on the cell surface in a dose-dependent manner (*p < 0.05). MTT assays showed that neither the 1 μg/mL nor 5μg/mL SW treatments showed significant inhibition of MA782 cell growth in vitro. The expression of iNOS and agr-1 in the 5 μg/mL SW-treated group were 4.75-fold higher and 3.7-fold lower than that in the untreated group, respectively (*p < 0.05). Mean fluorescence intensity of CD16/32 expressed in the cells treated with 5 μg/mL SW was significantly higher in comparison with the untreated group (65 vs. 7, *p < 0.05), though the percentage of CD16/32-positive cells were not significantly different. Furthermore, the expression of CD206 and dectin-1 in the 5 μg/mL SW-treated group was significantly decreased (3.1±0.3% and 4.1±1.1%, respectively) in comparison with the untreated group (40±3% and 8.9±1.2%, respectively, both p < 0.05). In addition, the 5 μg/mL SW-treated group secreted more TNF-alpha (350 ±25 pg/mL) and less IL-10 (89±7.2 pg/mL) than the untreated group (80 ±3 pg/mL and 150 ±10 pg/mL, respectively, both p < 0.05). Conclusion: N-glycan-defective MA782 cells can induce the differentiation of BMDM into proinflammatory M1 macrophages in vitro.