Nanostring transcriptomic analysis of M(M-CSF) (M2-like) macrophages treated with antiChemR23 agonist or untreated.

Macrophages are a major component of the tumor environment and their accumulation often correlates with poor prognosis and resistance to anticancer treatments. In this study, we thus investigated the therapeutic interest to target ChemR23, a receptor of the resolution of inflammation, in cancers using an agonist monoclonal antibody, antiChemR23. In vitro experiments on M2-like macrophages treated by antiChemR23 agonist decreased their inflammatory phenotype. In vivo, treatment with antiChemR23 agonist increased mouse survival and decreased metastasis occurrence in a model of triple-negative breast cancer in correlation with modulation of TAM phenotype in the metastatic niche. Monocytes were treated in vitro with M-CSF at 50ng/ml (Isokine, 01-A0220) to obtain M(M-CSF) (M2-like) macrophages.After 3 days in culture, macrophages were incubated with 10µg/ml of antiChemR23 or hIgG1 antibodies for 24h. Then, cells were stimulated with 200ng/ml lipopolysaccharide (LPS) (Sigma-Aldrich) for 6h and cells were lysed using the RLT buffer (Qiagen) supplemented by 1% β-mercaptoethanol (Sigma-Aldrich). Total RNA was isolated using the RNeasy Mini Kit according to the manufacturer’s protocol (Qiagen).