Fig. 5.

Effect of MEKK4/7 inhibition on TNF + CPT-induced JNK1/2 and ERK1/2 activation. Serum-starved cells were treated with TNF + CPT for 4 h, 10 μM SP-600125 (SP) was added at 0, 1, and 2 h, and cells were further incubated. At the end of incubation (4 h), apoptosis was determined by DNA fragmentation assay (top), and cell extracts were analyzed by Western blot for detection of phosphorylated and total JNK1/2 and ERK1/2, procaspases-9 and -3, and active caspases-9 and -3 (bottom). Actin immunoblotting was performed as an internal control for equal loading. Representative blots from 3 experiments are shown. Values are means ± SE of 3 observations. *Significantly different from A. #Significantly different from B.