Fig. 6. The antitumor effects of regorafenib in vivo are PUMA-dependent.

A Nude mice were injected s.c. with 5 × 10⁵ WT or PUMA-KO HCT116 cells. After 1 week, mice were treated with tazemetostat, 5-FU, or their combination as indicated. Tumor volume at indicated time points after treatment was calculated and plotted with P values, n = 6 in each group. B At the end of the treatment, the mice were sacrificed and the tumors were removed and weighed. C Mice were treated with tazemetostat, 5-FU, or their combination as in (A) for 4 consecutive days. The PUMA expression in the indicated tumors were analyzed by western blotting. D Mice were treated with tazemetostat, 5-FU, or their combination as in (A) for 4 consecutive days. Paraffin-embedded sections of WT or PUMA-KO tumor tissues were analyzed by active caspase 3 staining. Active caspase 3-positive cells were counted and plotted. E Mice were treated with tazemetostat, 5-FU, or their combination as in (A) for 4 consecutive days. Paraffin-embedded sections of WT or PUMA-KO tumor tissues were analyzed by TUNEL staining. TUNEL-positive cells were counted and plotted. The results were expressed as the mean ± SD of three independent experiments. **P < 0.01.