Fig. 4: HSD promoted MDSC differentiation and functional transformation.

a, b M-MDSCs purified in tumour tissues from the NSD or HSD group were cultured in RPMI-1640 medium containing 10% FBS and 10 ng ml⁻¹ GM-CSF for 2, 3 or 4 days. Population of CD11b⁺F4/80⁺ cells was evaluated by flow cytometry. One-way ANOVA with post hoc Bonferroni correction; n = 10 mice per group; *p < 0.05. Bars are expressed as the means ± SEM of three replicates. c, d mRNA expression was examined using Agilent Mouse GE v2 Microarrays (4 × 44 k format) after tumour-infiltrating M-MDSCs were isolated from the NSD or HSD group. DEGs in the chip analysis and mRNA expression levels of representative HSD-regulated genes involved in MDSC function from the HSD group; n = 5 for the NSD group and 6 mice for the HSD group. e, f Tumour-infiltrating M-MDSCs from the NSD or HSD group were cultured in RPMI-1640 medium containing 10% FBS for 24 h. The concentrations of IL-12, TNF-α and IL-10 in the supernatant were tested by ELISA, and NOS2 and Arg1 mRNA expression levels were examined by qRT-PCR. Two-tailed Student’s t test; n = 5 for NSD and six mice for the HSD group; *p < 0.05 and **p < 0.01. Bars are expressed as the mean ± SEM of three independent replicates with isolated cells pooled from the same group of mice. g, h The effects of HSD on macrophage infiltration, IL-12 and IL-10 levels and angiogenesis (CD31) in tumour tissues were evaluated by immunofluorescent imaging. Green, F4/80; blue, DAPI nuclear staining; red, IL-12, IL-10 or CD31; scale bar, 100 μm. The number of F4/80⁺IL-12⁺ cells, F4/80⁺IL-10⁺ cells and vessels (CD31⁺ cells) in high-power optic (for F4/80⁺IL-12⁺ cells, F4/80⁺IL-10⁺ cells, ×200 magnification; for vessels (CD31⁺ cells), ×400 magnification) field in stained sections (5 fields for each section; n = 5 individual tumours in the NSD group and n = 6 individual tumours in the HSD group). The two-tailed Wilcoxon rank-sum tests; n = 5 for the NSD group and 6 mice for the HSD group; ns not significant; **p < 0.01. Bars are expressed as the mean ± SEM. n = 5 data points for the NSD group and 6 data points for the HSD group (the average number of five fields for each section). For all panels, experiments were repeated twice. Source data are provided as a Source Data file.