Therapeutic activity of MTL-CEBPA in combination with checkpoint inhibitors. A, MC38 tumor–bearing mice were treated with MTL-CEBPA or NOV-FLUC control at 5 mg/kg from day 4 (twice a week). Anti–PD-1 antibody was intraperitoneally injected to the mice twice a week at 10 mg/kg. n = 5 per group. Mean and SEM are shown. P values were calculated using two-way ANOVA test. B, LLC tumor–bearing mice were treated with MTL-CEBPA or NOV-FLUC control at 3 mg/kg from day 3 (twice a week). Anti–CTLA-4 antibody was intraperitoneally injected to the mice on days 10, 17, and 24 (100 μg/mouse). Celecoxib was orally given to the mice at 50 mg/kg from day 3 (daily). Mean and SEM (n = 4) are shown. P values were calculated using two-way ANOVA test. C, LLC tumor–bearing mice were treated with MTL-CEBPA or NOV-FLUC (3 mg/kg from day 3, twice a week) in combination with lipofermata (2 mg/kg, twice per day from day 3, subcutaneously). In each experiment, P values were calculated in two-way ANOVA.