Fig. 5.

Docetaxel differentiates MDSC into M1-like phenotype in vitro and selectively inhibits M2-like phenotype of MDSCs. A, MACS column–purified MDSCs were assayed by flow cytometry, confirmed to be >90% Gr-1⁺CD11b⁺ cells, and further used for in vitro assays. MDSCs were cultured in the presence or absence of docetaxel at 11 nmol/L for 24 h followed by analysis for M1 (CCR7) and M2 (MR) markers. A, flow cytometric analysis of the percentage of CCR7- and MR-expressing MDSCs before and after docetaxel culture. B, flow cytometric analysis of Annexin V⁺ MDSCs before and after docetaxel culture. C and D, percentage of Annexin V⁺ and Annexin V⁻ cells in CCR7⁺ or MR⁺ MDSCs. Docetaxel induced apoptosis on MDSCs, and the cells that were differentiated into M1-like phenotype were negative for Annexin V but positive for CCR7. E, cytokine analysis of supernatants of MDSCs cultured in the presence or absence of docetaxel for 24 h. Docetaxel-treated MDSCs enhance IL-12 and suppress IL-10 production.