shRNA-mediated knockdown of BCL-W expression does not induce apoptosis of B-lymphoma cells and does not sensitize them to BH3-mimetic drugs targeting other prosurvival BCL-2 proteins. (A) shRNA knockdown of BCL-W was confirmed by western blotting in cell lines containing nontargeting control (shNT) and BCL-W–targeting (shBCL-W) shRNAs. Probing for HSP70 was used as a loading control. (B) Cell viability following doxycycline induction of shNT or shBCL-W expression over 96 hours. Cell viability was measured by the proportion of cells that were Annexin V and DAPI double-negative by flow cytometry. Error bars represent the SD for 3 independent experiments. (C) Cell proliferation following doxycycline induction of shNT or shBCL-W expression over 96 hours. Error bars represent the SD for 3 independent experiments. (D) Viability of BCL-W knockdown (shBCL-W) and control (shNT) cells following treatment with the indicated doses of BH3-mimetic drugs for 24 hours: S63845 (MCL-1 inhibitor), ABT-737 (BCL-2/BCL-XL/BCL-W inhibitor). Experiments were performed on cells following 72 hours of shRNA induction. Cell viability was measured by the proportion of cells that were Annexin V and DAPI double-negative by flow cytometry, and results were normalized to a DMSO-treated control sample. Knockdown of BCL-W did not sensitize any cell lines to ABT-737 or S63845 (Student t test, P > .05 for all). Error bars represent the SD for 3 independent experiments.