Enhanced apoptosis of ABT-737 combined to bortezomib in DLBCL (RL) and MCL (HBL-2) and effect on Bcl-2 family of proteins. (A,B) The combination induces significant apoptosis as shown by confocal microscopy, in RL (DLBCL, panel A) and HBL-2 (MCL, panel B) after 24 hours. ABT-737 (A) + bortezomib (B) showed statistically significant more apoptosis compared to any other treatment group (P .001). Mitotacker is red (mitochondria of live cells), Hoechst 33342 is blue (nuclei), and Yo-pro-1 is green (apoptotic cells). (C,D) Bcl-2, Mcl-1, BAX, BAK, Puma, and Noxa expression before and after treatment with ABT-737 at 100 nM (C, RL) or 10 nM (D, HBL-2) and bortezomib at 10 nM (RL) or 6 nM (HBL-2) was analyzed by Western blot. β-Actin was used to normalize protein loading.