GSE162353
Distinct population of immune suppressive macrophages differentiate from monocytic myeloid-derived suppressor cells in cancer
Here, we report that functional heterogeneity of macrophages in cancer could be determined by the nature of their precursors: monocytes (Mon) and monocytic myeloid-derived suppressor cells (M-MDSC). Macrophages differentiated from M-MDSC, but not from Mon were immune suppressive with genomic profile matching that of M-MDSC. Immune suppressive activity of M-MDSC derived macrophages was dependent on the persistent expression of S100A9 protein in these cells. S100A9 also promoted M2 polarization of macrophages. Tissue resident and Mon derived macrophages lacked expression of this protein. S100A9 dependent immune suppressive activity of macrophage was mediated via transcription factor CEBP/ß. The presence of S100A9 positive macrophages in tumor tissues was associated with shorter survival in patients with head and neck cancer and poor response to PD-1 antibody treatment in patients with metastatic melanoma. Thus, this study revealed the pathway of the development of immune suppressive macrophages and suggested approach to their selective targeting. Overall design: RNA-seq gene expression of source and derived macrophages from monocytes and M-MDSC cells of tumor burden patients