Figure 4.
Effects of TNF-α, ceramide NO, and cGMP on caspase 8 activity. Cells were treated for the indicated times with TNF-α (50 ng/ml)/CHX (1 μg/ml) (control) with or without SNAP (300 μM), D609 (25 μg/ml), C2 Cer (50 μM), 8 Br-cGMP (3 mM), and ODQ (1 μM) as indicated in the key. Caspase 8 activity was measured in cell lysates as described in Materials and Methods. Values are expressed as a percentage of those observed in the control. Analysis of values measured in the cell samples treated with TNF-α/CHX + SNAP vs. those measured in cell samples treated with TNF-α/CHX + SNAP + ODQ showed a statistically significant difference at 20 min (P < 0.01, indicated by the symbol ++) but not at 90 min (n = 5).