Therapeutic targeting of macrophages improves chemotherapy response and elicits neutrophil-dependent therapy resistance

Macrophages and neutrophils are almost invariably the most abundant intratumoral immune cells, and recent studies have revealed a sinister role for these cells in limiting chemotherapy efficacy. However, how these tumor-educated myeloid cells influence chemotherapy response is incompletely understood. Targeting tumor-associated macrophages by CSF-1 receptor (CSF-1R) blockade in a pre-clinical transgenic mouse model for breast cancer improved the anti-cancer efficacy of cisplatin. Importantly, our findings reveal that macrophage blockade in combination with cisplatin treatment evokes a compensatory neutrophil response limiting the therapeutic synergy of this therapy combination. Here we characterize neutrophils and macrophages gene expression profile from the tumor of mice treated with anti-CSF-1R, Control antibody, Cisplatin/anti-CSF-1R or cisplatin/control ab. Overall design: Intervention studies combining anti-CSF1R and chemotherapy in a transgenic mouse model for breast cancer.