Fig. 4. CDDO and ara-C induce cleavage of caspase-3 and PKC. A, U-937(left panel) and U-937/Bcl-xL (right panel) cells were treated 5 µM CDDO for 12 and 24 h. Total cell lysates were subjected to immunoblotting with anti-caspase-3. FL, full length; CF, cleaved fragment. Fold increase in caspase-3 CF as determined by densitometric scanning is included below the panels. B, U-937 and U937/Bcl-xL cells were treated with 10 µM ara-C and harvested at 6 h. Total cell lysates were analyzed by immunoblotting with anti-caspase-3. C, U-937 (left panel) and U-937/Bcl-xL (right panel) cells were treated with 5 µM CDDO for 12 or 24 h. Lysates were analyzed by immunoblotting with anti-PKC; IB, immunoblot.