Influence of U73122 on SCF inhibitory effect on ionizing radiation-induced apoptosis on primary CD34⁺ cells.

Human CD34⁺ bone marrow cells were pretreated or not 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. Phosphatidylserine externalization, as assessed by the binding of annexin V–FITC on the propidium iodide–negative population, was evaluated after 24 hours.