TOX suppression leads to cell cycle arrest and elevated cell cycle repressors. (A) FACS analysis of cell proliferation by BrdU incorporation in TOX-sh Hut78, HH, and SZ4 cells compared to control (CTR) cells. For BrdU incorporation assay, transduced Hut78 cells were pulsed with 10 μM BrdU for 45 minutes, whereas transduced HH and SZ4 cells were pulsed for 2 hours. (B) Cell cycle distribution in TOX-sh cells compared to CTR cells. (C) CDKN1B and CDKN1C transcript levels in TOX-sh and CTR. qRT-PCR was performed using primers specific for CDKN1B, CDKN1C, and GAPDH mRNA. The level of CDKN1B and CDKN1C mRNA was normalized to that of GAPDH and is depicted as the fold change compared to CTR cells. *P < .05, **P < .01, and ***P < .001 by 2-tailed Student t test with Welch correction. Error bars indicate standard error of the mean. Data depicted are representative of at least 3 independent experiments. (D) p27 and p57 protein levels in TOX-sh and CTR cells.