ALK shRNA inhibits the growth of human ALCL cells. (A) Percentages of human (TS, 80%) and murine (CD4-43, 8%) ALK⁺ cells transduced with pSRG-A5 vector as measured by EGFP expression by FACS analysis. (B-F) Human and murine ALCL ALK-A5⁺ cells decrease over time. Percentages of EGFP⁺ cells in pSRG-A5 or pSRG retrovirally transduced human ALCL cells SU-DHL-1, TS, and Karpas 299, human lymphoblastoid cells CCRF-CEM (ALK^–), and murine NPM-ALK (CD4-43) cells were determined over time. These findings are representative of at least 3 different experiments. In B-F, ♦ indicates pSRG-A6; ▪, pSRG-A5. (G) Percentages of BrdU/ALK-A5⁺ ALCL cells decrease over time. ALK-A5–infected TS cells were cultured over time and the percentages of BrdU⁺ cells within EGFP^– and ⁺ cells were calculated at different intervals. These findings are representative of at least 3 different experiments. Numbers represent the percentages of positive cells for each quadrant. (H) Percentages of BrdU⁺ TS cells over time after transduction with pSRG-A5 and pSRG-A6 viruses. TS cells were transduced with retroviral ALK-A5 or ALK-A6 pSRG vectors. BrdU incorporation of EGFP+ and EGFP^– cells was established as described in “Materials and methods.” ▪ indicates pSRG-A5; □, pSRG-A6. Percentages of total are indicated. Normalized ratio of BrdU⁺ cells among EGFP⁺ or EGFP^– cells was calculated over time. (A-F, H) Error bars indicate SD.