Figure 4. Effects on apoptotic signaling pathways by 15-d-PGJ₂. Control cells were assigned a value of 1, and other values were expressed relative to these and were plotted against the time after 15-d-PGJ₂ treatment. Data are expressed as mean ± SD (n = 3). *p < 0.05, **p < 0.01. (A) Caspase activation induced by 15-d-PGJ₂. Cells were incubated with 20 µM 15-d-PGJ₂ and troglitazone for the indicated periods of time. (B) Effects of caspase inhibitors on 15-d-PGJ₂-induced apoptosis. Cells were treated with 20 µM 15-d-PGJ₂ in the presence or absence of Z-VAD-FMK (2.5-20 µM), or Z-DEVD-FMK (2.5-20 µM) for 24 hrs. Then cells were processed for detection of fragmented mono- and oligonucleosomes by ELISA. (C) Cytochrome c release from mitochondria. Cells were incubated with 20 µM 15-d-PGJ₂ for the indicated periods of time.