Fig. 3

MCa-M3C orthotopic tumor response to combined losartan and single-dose or fractionated dose radiotherapy. a MCa-M3C orthotopic tumor growth and response curves of control, losartan alone, 20 Gy local single-dose irradiation alone (S-IR), 20 Gy five fractionated dose irradiation alone (F-IR), combined losartan with single-dose irradiation (Los + S-IR), and losartan with fractionated dose irradiation (Los-F-IR). Los indicates the start losartan treatment; RT indicates single-dose irradiation; and the FRT + arrows indicate the schedules of 5 fraction irradiation treatment. b Mean tumor growth time (days) for tumors to reach a mean volume of 500 mm³. Results show that S-IR, F-IR, Los + S-IR, or Los + F-IR treatment significantly delays tumors growth for 8 to 16 days compared to control, or losartan alone treatment (Unpaired t test, all P < 0.0001; 95% confidence interval between 5.292 to 10.04 and 10.35 to 16.05). In addition, the combination of Los + S-IR, or Los-F-IR treatment significantly enhanced tumor response compared to radiation alone (S-IR or F-IR) by increasing TGD an additional 5 days (Los + S-IR vs S-IR, or Los + F-IR vs F-IR; Unpaired t test, both P < 0.025; 95% confidence interval between 1.405 to 8.150 and 1.457 to 8.343). Losartan alone did not show an anti-tumor effect (Losartan vs Control, P > 0.05). Data are presented as Mean ± SEM; P < 0.05 is considered statistically significant (N = 9–10/group)