Figure 5
Suppression of tumour growth and enhanced survival by repeated dosing of VNP pRA-TR and γ-irradiation. (A) Regression curves for tumour growth after treatment with two doses of VNP pRA-TR and radiation (n=4), two doses of PBS and radiation (n=4), and PBS alone (n=11). Experimental groups received intravenous injection with PBS or VNP pRA-TR at days 0 and 6 (small arrows), followed by 2 Gy irradiation 2 days after experimental treatments (days 2 and 8; large arrows). Significant differences in tumour volume after redosing VNP pRA-TR and radiation were observed at all time points except days 0 and 2 in comparison with the PBS control group (P<0.05). (B) Estimates of time to tumour volume of 1000 mm3 show a delay of 30 days after two doses of VNP pRA-TR with irradiation in comparison with the PBS control (*P<0.05; redosed VNP pRA-TR+2 Gy, in comparison with all other groups). (C) Kaplan–Meier survival curves for the treatment groups in (A). At 30 days of follow-up, 100% of mice survived with two treatments of VNP pRA-TR with 2 Gy irradiation, compared with 25% after repeated dosing with PBS and 2 Gy, and no survival from PBS controls (log-rank test, P<0.05).
