Figure 4. Therapeutic application of 131I after NIS gene transfer in vivo.

Kras;p53 mice were treated with three cycles of i.v. injection of polyplexes on days 0/4/7 followed by i.p. injection of 55.5 MBq ¹³¹I 48 h later, on days 2/6/9. Tumor sizes were monitored weekly by MRI. Exemplary MRI images of endpoint tumor sizes from an LPEI-PEG-GE11/NIS + ¹³¹I- (A), an LPEI-PEG-GE11/ antisenseNIS + ¹³¹I- (B) and a NaCl + NaCl-treated Kras;p53 mouse are shown (C). Tumors are highlighted by red dotted lines. (D) Mice treated with LPEI-PEG-GE11/NIS + ¹³¹I (n=6) showed a stabilization in tumor volume compared to control groups LPEI-PEG-GE11/antisenseNIS + ¹³¹I (n=3; mean ± S.E.M.; *p<0.05) and NaCl + NaCl (n=4; **p<0.01). Mean tumor volumes (solid lines) and volumes for individual mice (dotted lines) are shown. (E) Injection of LPEI-PEG-GE11/NIS + ¹³¹I led to an increased overall and median survival in the therapy group (n=6) compared to control groups injected with LPEI-PEG-GE11/antisenseNIS + ¹³¹I (n=3; n/s) or NaCl + NaCl (n=4; n/s).