C59 Inhibition of the Wnt-β-catenin signaling pathway synergistically enhances the efficacy of anti-CTLA-4 antibody immunotherapy in the B16 melanoma model. A. Combination inhibition of Wnt-mediated signaling and anti-CTLA-4 blockade synergistically suppresses B16 melanoma development in vivo. B16/F10 tumor-bearing mice were administered C59 alone at 5 mg/kg/day by oral gavage, anti-CTLA-4 mAb alone at 100 μg via intra-peritoneal injection every 3 days, or the combination. Control mice (UT, untreated) received daily vehicle control by oral gavage and isotype control antibody every 3 days. 5-6 mice per group. Representative of two independent experiments. B. Inhibition of Wnt secretion enhances the activation of B16/F10 melanoma-infiltrating CD8+ T cells. Tumor-infiltrating 41BB+CD8+ T cells in each treatment group were analyzed by flow cytometry. 4 mice per group. Representative of 2 independent experiments. P value based on a one-way ANOVA. C. Inhibition of Wnt secretion augments anti-CTLA-4 mAb-induced expansion of TRP2-specific CD8+ T cells in B16/F10 melanomas based on dextramer flow cytometry analysis. 4 mice per group. Representative of 2 independent experiments. P value based on a one-way ANOVA.