(a) C57BL/6J mice were implanted with GL26-Luc cells, GNVs were loaded with Stat3 inhibitor JSI-124 and then intranasally administrated to mice. The mice were imaged on post-injection days as indicated in a. A representative photograph showing the brain tumour signals of a mouse from each group (n=5) (a, left). The growth potential of injected GL26-Luc cells was determined by dividing photon emissions of mice treated with PBS by the photon emissions of mice treated with GNVs, JSI-124 or GNVs–JSI-124 (a, right, top). The results are based on two independent experiments with data pooled for mice in each experiment (n=5) and presented as the mean±s.e.m.; *P<0.05. Surviving percentage of GNVs–JSI-124-treated mice was compared with control mice. One representative experiment of two independent experiments is shown (n=5) (*P<0.05) (a, right, bottom). (b) Tumour cells were injected s.c. into BALB/c mice (CT26, 1 × 106 per mouse, left, top) or NOD–SCID mice (SW620, 5 × 106 per mouse, left, bottom). After tumour cells were injected, mice were treated with DiR dye-labelled agents as listed in Fig. 5b via i.v. injection every 3 days for a total of ten injections. Tumour volume was measured every 3 days. On day 30 after tumour cells were injected, tumours were removed and imaged with a Kodak Image station. Representative images of tumours from each group (n=5) are shown (b, middle). Right panels show the mean intensity of the DiR fluorescent signals of tumour (mean net intensity=sum intensity/area, n=5). The results are presented as the mean±s.e.m. **P<0.01 and ***P<0.001 (one-way and two-way analysis of variance, ANOVA). (c) CT26-Luc tumour cell-bearing mice were i.v. injected with luciferase siRNA (50 pmol per mouse in 200 nmol GNVs), luciferase siRNA carried by GNVs, or FA and luciferase siRNA co-delivered by GNVs every 3 days for a total of five injections. Representative images (left, n=5) and mean intensity of the luciferase activity of CT26-Luc tumour (right, mean net intensity=sum intensity/area, n=5) before and after treatments are presented. *P<0.05.