sEphB4-Alb inhibited insulinoma growth and extended longevity in RT2 Dll4
+/+ and Dll4
+/- mice. A, Average tumor volumes developed by 13.5-week old RT2 (Dll4
+/+ or Dll4
+/-) male mice previously treated for 3.5 weeks with drug vehicle (PBS) or sEphB4-Alb (10 mg/kg). All the groups had 6 animals and were treated i.p. 3 times a week. B, Survival rates in RT2 Dll4
+/+ and RT2 Dll4
+/- treated with vehicle (PBS) or sEphB4-Alb (5 mg/kg). All the groups had 10 animals and were treated i.p. 3 times a week. Survival rate was calculated as the percentage of live mice at the end of each week relative to the initial number of the animals per experimental group. C, Sections of tumors harvested at the end of the experiment mentioned in A were co-stained with anti-PECAM (red) and anti-α-SMA (green) as described in Fig. 1C. D, Sections of tumors harvested at the end of the experiment mentioned in A were co-stained with anti-PECAM (red) and anti-NG2 (green). The percentage of PECAM-positive structures covered by NG2-positive area was measured as a parameter of pericyte recruitment (right). Kaplan-Meier product-limit estimation with Breslow generalized Wilcoxon test was used for survival analyses. Other data were analyzed using Mann-Whitney-Wilcoxon test. Error bars represent SEM. * P < 0.05 and ** P < 0.01 were considered significant and highly significant, respectively.