Fig. S7.
Contribution of the different cellular compartments to the total tumor mass. (A) Parts of the whole graph showing the relative area occupied by the four different cellular compartments in tumors: cancer cells (blue), BM-derived cells (yellow), non–BM-derived cells expressing collagen (red and green), and non–BM-derived cells not expressing collagen (only red). COL-EGFP/DsRed+ mice that also expressed EGFP under the collagen α1(I) promoter were lethally irradiated and reconstituted with BM cells from B6 EYFP+ mice. After 2 mo, window chambers were installed and cancer cells (MC57, Pro4L, or MC38) expressing Cerulean were injected in three independent longitudinal experiments. Hosts were Rag−/− for MC57 and Pro4L, and Rag+/+ for MC38 (n = 1 per cell line). Areas were quantified in images obtained from established 12-d MC38 tumors and 22- to 28-d MC57 and Pro4L tumors (four or five regions per mouse and cell line). Each column represents an individual tumor region. The total cellular area quantified is indicated below each column. On average, fibroblasts accounted for 30 ± 5.8% of the stroma, whereas BM-derived cells were 67 ± 12.2%. (B) Representative images of a region analyzed for quantification in A are shown from a 28-d MC57 tumor. (C) Z stacks were obtained from a 22-d MC57 tumor. Z stacks were generated by acquiring nine images (optical slices) at 8-μm intervals (total depth of 72 μm). Top and bottom views of a 3D reconstruction of a Z stack, corresponding to Movie S1, are shown. (D) The volume occupied by the different cellular compartments in the 3D Z stack was quantified. A representative graph is displayed showing the relative contribution of each compartment to the total cellular volume (2.15 × 108 μm3). Percentages are similar to those in A, where areas were quantified instead of volumes, showing that both approaches rendered similar results.