Figure 6.

GTN inhibits spontaneous colon cancer tumorigenesis. (A) Scheme of tamoxifen inducible CPC-APC model of spontaneous tumorigenesis. Mice were given a dose of tamoxifen (1.5 mg/kg, i.p.) once per day for 3 days to induce colon carcinogenesis and GTN (30 mg/kg, gavage) was administered three times per week, starting on day 7. Tumors were allowed to develop for 30 days, after which mice were sacrificed and tumors were processed for subsequent analysis. (B) Multiplicity, load (sum of all tumors diameters in mm, per group) and size of tumors per group at the end of the experiment. (C) Representative H&E images of colon tumors from control and GTN-treated mice, magnification 2×. Arrows highlight tumors. (D) Representative colonoscopy images from Cre-negative (no tumor induction possible), control and GTN-treated mice on day 23. (E) ELISA was used to determine protein concentration of secreted cytokines from tumors cultured for 24 h, normalized to mg of tissue. Mean ± standard error, *P ≤ 0.05, **P ≤ 0.01 and ***P ≤ 0.001. ANOVA, followed by Tukey’s multiple comparison test. *Statistical difference compared to control animals (treated with vehicle).