Fig. 2

Tumor growth and vascularity are reduced, and tumor necrosis is observed following short-term combination. a Quantification of tumor volume and (b) body weight. Xenograft mice were divided into five groups according to the administration schedule: vehicle (PBS), IR alone (4 Gy/day), CKD-516 alone (3 mg/kg), and CKD-516 (3 mg/kg, day 1 or days 1 and 5) combined with IR. We irradiated the tumor mass at 4 Gy for 5 consecutive days from day 20 to day 24 when tumor volume reached 600–800 mm³. We investigated two treatment schedules of CKD-516 (day 1 or days 1 and 5) 1 h after IR via intraperitoneal injection (arrow: administration of CKD-516). Mice were sacrificed 24 h (25 days) and 72 h (27 days) after completion of the administration schedule (n = 6 per group). c The number of blood vessels was counted by IHC using the CD31 antibody in collected tumor tissues. d Histopathological analysis of tumor necrosis in mice tissues with H&E staining. The data are presented as the mean ± SE. * denotes p < 0.05, ** denotes p < 0.001, and *** denotes p < 0.0001