FOXO3A knockdown shows an antitumor effect in cHL cell lines. cHL cell lines were transduced with indicated lentiviral plasmids as described in “Materials and methods.” The dynamic of transduced cells was followed starting from the fifth day after transduction (day 0) and the percentage of fluorescent cells on day 0 was set as 100%. Fluorescence was measured every third day using flow cytometry. (A) Constitutive AKT activation (myrAKT) decreased the percentage of green fluorescent protein–positive (GFP⁺) cells in cHL cell lines except for L1236 and SUP-HD1. (B) Immunoblot was performed after sorting of GFP⁺ cells to confirm overexpression of myrAKT and FOXO inactivation. (C) Effect of FOXO3A shRNAs on the red fluorescent protein–positive (RFP⁺) population in cHL. (D) Protein of RFP⁺ cells was isolated after selection with puromycin for 2 days (4 µg/mL). shRNA efficiencies and specificities were confirmed with immunoblot. TUBB served as loading control for immunoblot analysis. All experiments were performed for at least 3 times and kinetics are shown as mean ± SD. Significance was calculated compared with the scrambled control using a 2-sided t test. *P < .05; **P < .01; ***P < .001; ****P < .0001. F3-1, FOXO3AshRNA-1; F3-3, FOXO3AshRNA-3; scr, scrambled control.