SNS-032 reduced the expression of antiapoptotic proteins. The total RNA and protein of CLL cells from the same set of 6 patients in Figure 1A were isolated after 6 hours (■) and 24 hours (●) of incubation with 0.1, 0.3, and 1 μM SNS-032. (A) The mRNA levels of Mcl-1, XIAP, and Bcl-2 were measured by real-time reverse-transcribed polymerase chain reaction, each performed in duplicate, and compared with time-matched controls. (B) A representative immunoblot from patient 4. (C) Quantitations of immunoblots of Mcl-1, XIAP, and Bcl-2 from the samples used in panel A. Levels of Mcl-1, XIAP, and Bcl-2 were normalized to actin and expressed as percentage of time-matched controls. (D) SNS-032–induced Mcl-1 reduction is independent of caspase activity. CLL cells were preincubated with pan-caspase inhibitor ZVAD-FMK (100 μM) or proteosome inhibitor MG-132 (10 μM) for 1 hour before incubating with 0.3 μM SNS-032 for 8 hours. PARP cleavage and Mcl-1 protein levels were visualized by immunoblotting.