Fig. 3.

In vivo immunohistochemical analysis of caspase 8 expression in U87ΔEGFR brain tumors. U87ΔEGFR cells were injected into the right frontal lobe of athymic rats. Cilengitide or phosphate buffered saline (PBS) was administered 3 times/week intraperitoneally starting on day 5 after tumor cell implantation. To assess the expression of caspase 8, athymic rats harboring U87ΔEGFR brain tumors were sacrificed at 14 days after tumor implantation. A subpopulation of caspase 8-positive cells was visualized using immunostaining (caspase 8-positive cells: caspase 8, red; nuclei: DAPI, blue) of U87ΔEGFR control xenografts (A) and U87ΔEGFR cilengitide-treated xenografts (B). The control sections exhibited scattered red fluorescence (A), whereas more punctate red fluorescence was observed in the cilengitide-treated xenografts (B). DAPI: 4’,6-diamidino-2-phenylindole.