SOX11i, alone or combined with IBN and venetoclax, enhances apoptotic cell death in resistant MCL cells. (A) Apoptosis was measured using an AnnV/PI assay in IBN-resistant cell lines (JeKo-1_IBN-R and JeKo-1_BTK-KD) and venetoclax-resistant cell lines (Mino_ABT-199-R and Rec-1_ABT-199-R) after 24 hours of cotreatment with Cpd R (20 μM) with IBN (10 μM) or ABT-199 (0.5 μM). (B) JeKo-1_IBN-R and Mino-VR cells were incubated with IBN (10 μM) ± Cpd R (20 μM), and ABT-199 (0.5 μM) ± Cpd R (20 μM) for 24 hours, after which C-PARP and CASP3 cleavage were monitored by immunoblotting analysis. β-Actin was assayed to ensure equivalent loading and transfer. (C) CD19 knockout cells (JeKo-1_IBN-R) were treated with varying concentrations of IBN (0-16 μM) for 48 hours. Cell viability at each drug concentration was then quantified and expressed as a percentage relative to the DMSO control. (D) Patient-derived xenograft cells were treated with Cpd R at the specified concentrations (20-40 μM) for 2 different time points (24 hours and 48 hours). Cell viability was measured following treatment and compared to the DMSO control. VEN, venetoclax.