CCND1 knockdown does not induce resistance to venetoclax. (A) Protein lysates were prepared from cells 72 hours after nucleoporation with either control siRNA or CCND1 siRNA. Protein was subjected to sodium dodecyl sulfate–polyacrylamide gel electrophoresis and western blotting for CCND1, MCL1, BCLXL, BCL2, BIM, and ACTIN. Densitometry quantification of CCND1 relative to control siRNA and normalized to actin is shown for each cell line. (B) The same cells were fixed, permeabilized, and stained with propidium iodide to measure DNA content. Gates depict percentage of cells in G₁, S, and G₂/M. (C) Starting at 48 hours after siRNA nucleoporation, cells were treated with indicated doses of venetoclax for 24 hours followed by staining with Annexin V–fluorescein isothiocyanate to measure apoptosis. Data are presented as the mean ± standard error of 3 independent experiments.