In vitro activity: In bone marrow-derived macrophages (BMDMs), BLZ945 specifically inhibits CSF-1-dependent proliferation with EC50 of 67nM, and decreases CSF-1R phosphorylation. BLZ945 blocks the reciprocal effects between macrophages and glioma cells on the survival, proliferation and/ or polarization of each other to promote tumorigenesis.

Kinase Assay: BLZ945 is a potent, orally bioactive, and selective CSF-1R (colony stimulating factor 1 receptor) inhibitor with IC50 of 1 nM, it is more than 1000-fold selective against its closest receptor tyrosine kinase homologs.

Cell Assay: Cell growth rate is determined using the MTT cell proliferation kit. Briefly, cells are plated in triplicate in 96-well plates: 1,000 cells per well for glioma cell lines, 5 x 1,000 cells per well for BMDM and CRL-2467, and 2.5 x 1,000 cells per well for HUVEC and HBMEC cell lines. For all experiments, media is changed every 48 h. Cells are grown in the presence or absence of 6.7–6,700 nM of BLZ945, or 8 μg/mL of CSF-1R neutralizing antibody. BMDM and CRL-2467 cells were supplemented with 10 ng/mL and 30 ng/ mL recombinant mouse CSF-1, respectively. Reduction of the MTT substrate is detected by colorimetric analysis using a plate reader as per the manufacturer’s protocol, and measured at 595 nm and 750 nm on a spectraMax 340pc plate reader.