Fig. 3: Ferrichrome promotes phagocytosis and cancer cell killing capacity in macrophages in vitro and in vivo.

a Representative image and quantification of phagocytosis of fluorescent E. coli bioparticles by BMDMs with the presence of ferrichrome (20 µM) or vehicle (control) as evaluated by fluorescent microscopy imaging on the FITC channel (n = 3 experiments). b Antitumor activity of BMDMs against luciferase-expressing pancreatic cancer cells Panc02 in the presence of ferrichrome or vehicle control. Cancer cells were co-cultured with BMDMs at a macrophage: cancer cell density of 1:1 for 48 h. Tumor cell survival was determined by normalizing luminescence to tumor-only controls (n = 3). c Representative images of evidence of phagocytosis of cancer cells by macrophages in ferrichrome-treated tumors (right panel) or vehicle-treated tumors (left panel). Images were quantified using ImageJ software. A phagocytic event is defined by the presence of cancer cell marker Cytokeratin 19 (CK19) (red) within the macrophage markers F4/80 (green) as evaluated by dual-immunofluorescence analysis (n = 4 mice). Bar on micrographs indicates 50 µm. Mean ± SEM shown. *p < 0.05, and ***p < 0.001 as determined by Student’s t test.