DC promotes secondary tumor formation from fat pad grafts of 4T1 cells. (a) 4T1 tumor and metastasis model. 4T1 cells were injected into the flanks of Balb/c mice. Tumor tissue was extracted from the flanks and chopped into small fragments. Cells were labeled with Vybrant CM-DiI. The labeled tissue fragments were grafted into the fat pads of another series of mice, which were then intraperitoneally injected with vehicle or treated with DC. After 14 days, mice were killed and secondary tumors quantified. (b) Brightfield and epifluorescence (Vybrant CM-DiI) image of secondary tumor in lung (arrow points at blood vessel). Scale bar = 1.0 mm. (c) Epifluorescence image (Vybrant CM-DiI) in intestine (arrows point at tumor nodules). Scale bar = 1.0 mm. (d) Image as in panel c, but overlay with phase contrast image (arrows point at Vybrant CM DiI-labeled cells [red]). Scale bar = 200 μm. (e) Mice were treated as described for panel a and the number of secondary tumor nodules in the intestine determined. DC, sodium deoxycholate.