Downregulation of STAT6 triggers apoptosis of STAT6-mutated cHL tumor cells. (Top) ShRNA-mediated downregulation of total and phophoSTAT6 by western blotting in 4 cHL cell lines (1 representative experiment per cell line is shown, of 2-4 independently performed, that gave reproducible results); β-tubulin is used as a loading control, and the normalized levels of total and phosphoSTAT6, quantified by densitometry, are shown below the respective blots (solid lines denote distinct gels that were loaded with the same protein lysates and blotted separately). (Bottom) Raw percentage of live cells (AnnexinV-negative by flow cytometry) over time, after transduction of STAT6 shRNA-1 and control shRNA (day 0 = 96 hours after transduction and 48 hours after puromycin selection). Error bars (standard error of the mean) refer to at least 2 or 3 independent experiments per cell line per time point. P values refer to unpaired, 2-tailed t test. Supplemental Figure 14 shows the same data after normalizing the percentage of live cells in the shRNA-1 sample to the corresponding nontargeting shRNA control sample (set at 100%).