Effects of PI3-kinase and MAPK^p42/44inhibitors on survivin expression and cell cycle in CD34⁺cells.

CD34⁺ cells were pretreated with either DMSO, 1 and 5 μM LY294002 (A), or 20 and 40 μM PD98059 (B), followed by incubation with 100 ng/mL each Tpo, SCF, and FL. Cells were fixed at 4, 8, and 18 hours after growth factor stimulation and analyzed for survivin protein and cell cycle. Percent inhibition of survivin expression was calculated as percent reduction of mean channel fluorescence of survivin compared to DMSO control at each time point. Percent increase in G₀/G₁ phase cells was calculated based on the increase in G₀/G₁ population over DMSO control at each time. Data are shown as means ± SEM of 3 independent experiments. *P < .05.