Macrophages derived from coculture promote tumor growth and angiogenesis. (A) Colony cells promote tumor growth in wild-type C57BL/6 mice. Mice were injected with RM1 tumor cells (1 × 105) alone or with colony cells (1 × 104; n = 3∼5). (B) Representative pictures of tumor sections stained for CD31 (red). Tumors that were co-injected with colony cells showed a higher vascular density. Arrowhead indicates representative vessel. DAPI indicates staining for nuclei (blue). Scale bar, 100 μm. (C) Quantification (percentage) of vascular area in tumor sections shown in (B; n = 3). (D) Quantification of vessel area in tumor sections from indicated days (n = 3). (E) Quantification of vessel number in tumor sections from indicated days (n = 3). (F) Immunolabeling (i,ii) and 3D surface rendering (iii,iv) of colony cells (DsRed) and vessels (MECA, green) after colony cells and IMECs were injected with matrigel for 7 days. Colony cell (arrowhead) is bridging 2 endothelial cells. Scale bar, 50 μm. (G) Model of IMEC-induced M2 macrophage differentiation (*P < .05; **P < .01; unpaired Student t test).
