Lentiviral ALK shRNA leads to cell-cycle arrest and apoptosis of ALCL cells. (A-B) Anti–ALK-A5 leads to G₁ cell-cycle arrest. TS cells transduced with the indicated constructs were harvested 96 hours after infection and stained with propidium iodide (PI) to determine the corresponding fractions in G₀/G₁, S, and G₂-M phases. Lysates were analyzed by Western blotting with the indicated antibodies. (C) Anti–ALK-A5 leads to cell death. Percentages of TMRM^– cells were calculated in TS cells 4 and 5 days after infection. (A, C) Error bars indicate SD. (D) Loss of NPM-ALK leads to caspase activation. TS cells transduced with empty vector, TM2, or ALK were harvested 96 hours after transduction and immunoblotted with the indicated antibodies. These findings are representative of 4 different experiments.