Figure 1.

SRX3305 is cytotoxic to CLL cells in a dose-dependent manner. Four CLL cell lines, OSU-CLL (A), HG-3 (B), MEC-1 (C), and MEC-2 (D), were treated with increasing concentrations of SRX3262, SRX3305 (BTK/PI3K/BRD4 triple-inhibitor), ibrutinib (BTK inhibitor), idelalisib (PI3K inhibitor), or JQ1 (BET inhibitor) for 72 h. Proliferation was assessed via MTS assay, and results are given as % proliferation normalized to vehicle. Error bars indicate SEM (n = 3 independent experiments per cell line). IC₅₀ values (mean ± SEM) are noted for each inhibitor within the in-figure legends. Dose-dependent decrease in CLL cell proliferation is observed with asterisks denoting significance vs. vehicle. (E) OSU-CLL and (F) HG-3 cells were treated with DMSO vehicle (Veh), SRX3305 (0.5, 1, 2 µM), ibrutinib (Ibr, 1 µM), idelalisib (Idel, 1 µM), or JQ1 (0.5 µM) for 24 h. Percentage of apoptosis (annexin V-positive cells) was evaluated via flow cytometry (n = 3 independent experiments per cell line). Results are given as mean ± SEM. Asterisks denote significant inhibitor-induced apoptosis vs. control vehicle. * p < 0.05, ** p < 0.01, *** p < 0.001.