Naratuximab emtansine–resistant and parental SU-DHL-4 differ based on their dependency on antiapoptotic proteins. (A-B) BH3 profiling of naratuximab emtansine–resistant (red bars) and parental SU-DHL-4 (blue bars) exploring the role of BCL2/BCLXL (BAD), BCL2 (ABT-199), and BCLXL (A-133) (A), as well as MCL1 (MS1) and BFL1 (FS1) (B). (C) MTT results were obtained in naratuximab emtansine–resistant and parental SU-DHL-4, which were exposed to increasing concentrations of the MCL1 inhibitor S63845. Bar plots correspond to IC₅₀ values of resistant (red) and parental (blue) lines. ∗P < .05.