Functional hierarchy of Bcl-2 members in determining resistance to venetoclax. (A-B) CLL cells were cultured on 3T3 or 3T40L for 24 hours. After detachment, cells were treated with 5 µM QVD and 100 nM venetoclax for an additional 24 hours and then lysed with NP-40 lysis buffer. Shown are the protein lysates (input), the proteins in the lysates that were pulled down (Bim IP), and the proteins still present in the lysates after the IP (cleared lysate) (A), as well as the coimmunoprecipitated proteins of the Bim IP (B). (C-D) CLL cells were cultured on 3T40L for 24 hours. After detachment, cells were left untreated (-) or treated with 5 µM QVD and 100 nM venetoclax (ABT199) supplemented or not with 100 nM S-63845 and 300 nM A-1331852 (Triple) for 24 hours before lysis. Shown are the protein lysates (input) (C) and the coimmunoprecipitated proteins of the Bim IP from patients #15 and #16 (D). IP, immunoprecipitation.