Influence of belinostat, ruxolitinib, PRN694, and ibrutinib on apoptotic priming and viability. (A-C) Impact of 24-hour exposure to 1 μM belinostat, ruxolitinib, PRN694, or ibrutinib on BH3 profiling, shown as delta percentage cyt c loss (delta is percentage loss of T-PLL cells treated with drug minus percentage loss of T-PLL cells in DMSO). Results show individual delta values, as well as means ± standard error of the mean (SEM) for 6 (belinostat), 7 (ruxolitinib), 3 (PRN694), and 4 (ibrutinib) different T-PLL samples (paired Student t test). Overall priming was evaluated with the PUMA peptide at 0.5 μM (A), BCL-2 dependency with venetoclax at 0.1 μM (B), and BCL-2 dependency with MS1 peptide at 0.5 μM (C). (D) Induction of apoptosis shown as percentage of viable (annexin V negative/Hoechst positive, relative to control) cells after a 24-hour exposure to DMSO, ruxolitinib 1 μM, belinostat 1 μM, PRN694 1 μM, or ibrutinib 1 μM and 4-hour exposure to increasing concentrations of DMSO alone and venetoclax (1 nM, 10 nM, 100 nM, 1 μM, and 10 μM; n = 24; mean ± SEM). (E) On the same dataset as in panel D, focused on venetoclax at 100 nM, showing individual values of samples treated with ruxolitinib, belinostat, and PRN694 (n = 24; paired Student t test). *P < .05; **P < .01; ****P < .0001. ns, not significant.