Investigation of FOXO1 function in endemic BL cells using CRISPR/Cas9 gene editing. (A) Summary of FOXO1 mutations detected in 7 human BL cell lines and 4 patient-derived xenografts. (B) Western blot showing FOXO1 protein expression and localization in BL cell lines and 4 patient-derived xenografts. PARP and α-tubulin were used as loading controls for the nuclear (N) and cytoplasmic (C) fractions, respectively. CRISPR/Cas9 gene editing in the Jiyoye cell line, analyzing bulk populations (C) and individual clones (D). Left panels show FOXO1 protein expression by western blot. Right panels show the effect on cell proliferation determined by Trypan Blue cell counting over a 7-day time course. (C) The mean and the standard deviation of 3 independent experiments are presented. (D) Each dot in the box-whisker plot (10th-90th percentile) represents the mean of 3 independent experiments performed with an individual clone. *P < .05, **P < .01, ***P < .001. NTC, nontargeting controls