GSE161771
Macrophage-targeted Therapy Unlocks Antitumoral Crosstalk Between IFN??-secreting Lymphocytes and IL12-producing Dendritic Cells
Macrophages often abound within tumors, express colony-stimulating factor 1 receptor (CSF1R), and are linked to adverse patient survival. Drugs blocking CSF1R signaling have been used to suppress tumor-promoting macrophage responses; however, their mechanisms of action remain incompletely understood. Here, we assessed the lung tumor immune microenvironment in mice treated with BLZ945, a prototypical small-molecule CSF1R inhibitor, using single-cell RNA sequencing and mechanistic validation approaches. We showed that tumor control was not caused by CSF1R+ cell depletion; instead, CSF1R targeting reshaped the CSF1R+ cell landscape, which unlocked crosstalk between antitumoral CSF1R- cells. These cells included IFN??-producing natural killer and T cells, and an IL12-producing dendritic cell subset, denoted as DC3, which were all necessary for CSF1R inhibitor–mediated lung tumor control. These data indicate that CSF1R targeting can activate a cardinal crosstalk between cells that are not macrophages and that are essential to mediate the effects of T cell–targeted immunotherapies and promote antitumor immunity. Overall design: Single-cell RNA sequencing (scRNAseq) of lung-infiltrating CD45+ cells from healthy mice (n=2), and lung adenocarcinoma-bearing mice treated with the CSF1R inhibitor BLZ945 (n=2) or vehicle alone (n=2).