sDll4-Fc inhibits KS tumor growth in vivo. (A) Athymic mice were implanted with 2 × 106 KS-IMM cells. When tumor sizes were approximately 100 mm3, mice were randomly assigned to treatment groups (6 per group) (day 0). Mice were treated by intraperitoneal injection of sDll4-Fc (10 mg/kg) or PBS, 3 times a week for 31 days. Tumor volume was measured 3 times a week. The P value was calculated by Student t test. (B) Just before tissue harvest, mice were infused with RCA-Lectin and hypoxyprobe. Tumor tissue structure was examined by hematoxylin and eosin staining. Perfused vessels were localized by RCA-Lectin, microvascular endothelial cells were localized by CD31 staining, and pericytes were localized by NG2 staining. Nuclei were counterstained with 6-diamidino-2-phenylindole dihydrochloride. Proliferating cells within the tumor were assessed by immunostaining with anti-Ki67 antibody. Apoptosis was examined with TUNEL assay. Hypoxia was assessed by immunostaining with anti-Hypoxyprobe antibody. Quantitation was performed with the use of Bioquant Image Analysis (Bioquant), and the relative fluorescence level is shown below the panel. The confocal images were taken at an original magnification ×60.
