Time-course study of the effect of LY294002 on the proliferation and survival of erythroid progenitor cells. Day 8 cells that contained 69% ± 4% erythroid progenitor cells were suspended at a concentration of 5 × 105/mL in 1.0 mL serum-free medium supplemented with 2 U/mL EPO with (•) or without (○) 50 μmol/L LY294002. After incubation and at the indicated periods, the cells were collected, washed twice in IMDM containing 0.3% BSA, and then plated into serum-containing fibrin clots with 2 U/mL EPO. After 7 days of incubation, the clots were fixed and stained with benzidine-hematoxylin. (A) Viability; (B) absolute number of viable cells; (C) percent expression for the number of erythroid colonies in relation to the value of 0 hours as 100%. The mean ± SD of triplicates is shown for C. +++P < .001, decrease v control (○); ***P < .001, decreasev 0 hours; #P < .05,###P < .001, increase v 0 hours.
