Caspase-3–mediated cleavage of Bcl-X_L.

WSU-CLL and ALL-REH cells were grown as described above and incubated with 200 nM Z-DEVD-fmk. Cells were harvested after 24 hours, and Bcl-X_L cleavage (panel A) and induction of apoptosis (panel B) were assessed as described in “Materials and methods.”