BCL2/BCL-XL codependence in ALL cell lines in vitro. (A) Protein expression by reverse phase protein array (RPPA) for anti-apoptotic BCL2 and BCL-XL (BCL2/BCL-XL) in 15 B-ALL and 13 T-ALL cell lines. The violin plots show the median expression, maximum (Q3 + 1.5 × interquartile range [IQR]), and minimum value (Q1 + 1.5 × IQR). Data were analyzed with 2-sided t test. (B) The protein expression levels of anti-apoptotic family members (BCL2, BCL-XL, and MCL1) and prodeath activators (BIM and BAX) determined by Western blot analysis. Whole-cell lysates from a panel of B- and T-ALL cell lines were separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and probed for the indicated antibodies. The cropped images (boxed) of cell lines reflecting specific ALL subsets generated from the single immunoblot across probed proteins. (C-D) BH3 profiling functional assay to measure apoptotic priming. Dependencies were measured in a panel of B- and T-ALL cell lines. All calculations were performed using GraphPad prism statistical software version 9.