Influence of U73122 on SCF inhibitory effect on ionizing radiation-induced N-SMase stimulation, ceramide generation, and apoptosis.

Ba/F3-Kit cells were pretreated with U73122 alone (1 μM; 1 hour) or with SCF alone (200 ng/mL; 30 minutes) or with U73122 and SCF, then irradiated at 4 Gy. Untreated cells are also indicated. Results are shown at maximum ceramide production (A), N-SMase stimulation (B; 10-15 minutes), and apoptosis evaluated by DAPI staining (24 hours; C). Values are the mean ± SD of 3 independent experiments (*P < .05).