CQ disrupts autophagy and sensitizes Bim^low MM cells to the HDACI/BH3 mimetic regimen. (A) H929 cells were exposed to 300 nM ABT-737 with or without 30 μM SBHA in the presence or absence of 50 μM CQ, after which immunoblotting analysis was performed to monitor LC3 processing, Bim expression, and PARP cleavage. (B) In parallel, flow cytometry was performed to determine the percentage of apoptotic H929 cells. (C) Alternatively, cells were lysed in CHAPS buffer and subjected to co-IP (IP with anti-Bcl-2, immunoblotting with anti-Bim). IP without anti-Bcl-2 (lane 1), cell lysate (lane 2), or both (lane 3) was performed as controls. (D) Similarly, PS-R cells were incubated with relatively lower concentrations of ABT-737 (300 nM) with or without SBHA (15 μM) with or without 50 μM CQ for 48 hours, followed by flow cytometry to monitor apoptosis. (E) Primary CD138⁺ cells derived from newly diagnosed (displaying low basal Bim levels, inset) or relapsed MM patients (n = 4; 2 samples each for Dx and R) were treated with 100 nM ABT-737 plus 10 μM SBHA in the presence or absence of 10 μM CQ for 24 hours, after which flow cytometry was performed to determine the percentage of viable cells (7-aminoactinomycin D [7AAD] staining-negative).