Fig. 6

miR-448 enhances the survival of CD8⁺ T cells by suppressing IDO1 function. The Kyn/Trp ratio was analyzed in the culture medium from a HT-29 and b HCT-116 transfected with miR-NC, or transfected with miR-NC followed by IFN-γ treatment, or transfected with miR-448 followed by IFN-γ treatment. The concentration of Kyn and Trp were determined by HPLC and the Kyn/Trp ratio was calculated. c, e Representative contour plots and d, f apoptosis quantification of FACS analysis for the percentage of apoptotic CD8⁺ T cells in miR-NC, miR-NC + IFN-γ, miR-448 + IFN-γ conditional medium systems from c, d HT-29 and e, f HCT-116 supernatant. a, b, d, f Mean ± SEM. a n = 9 measurements from three biological replicates performed in triplicate; b n = 6 measurements from two biological replicates performed in triplicate; c-f n = 3 biologically independent experiments. a, b, d, f Two-tailed Student’s t-test was performed for statistical analysis; *P < 0.05, **P < 0.01, ***P < 0.001. miR-NC: miRNA mimic negative control; miR-448: miRNA-448 mimic