Figure 1. Bioluminescence imaging and histological assessment of EGI-1 cells after xenotransplantation into SCID mice.
High correspondence between the bioluminescence signal in the liver (A) and the macroscopic detection of liver tumors at autopsy (arrow, B) after xenotransplantation of EGI-1 cells into SCID mice by intraportal injection. Before transplantation, EGI-1 cells were transduced with lentiviral vectors encoding the firefly luciferase gene. Mice were sacrificed once the bioluminescence signal intensity in the liver reached a value >105 p/sec/cm2/sr. Histological analysis of liver metastases showed that EGI-1 cells laid embedded in a rich stroma (H&E staining, C). By dual immunofluorescence for EGFP (green) and α-SMA (red), we showed that CAF were strictly adjacent to EGI-1-derived tumors, but coincident labeling between EGFP and α-SMA was never observed (D). In liver tumors formed by EGI-1 cells, FISH showed that α-SMA-positive CAF (green, E, F) co-expressed mouse (red, white arrow, E), but not human (red, F) Y-Chr, which was instead expressed by tumoral EGI-1 cells (F). High specificity of both Y-probes was confirmed in preliminary experiments. Original magnification: C-F, 200x, insets in E,F, 400x.