Effect of UNC0638 treatment on cell morphology, proliferation, and differentiation of primary adult human erythroid cells in culture. (A) Representative images of the morphology of primary adult human erythroid cells differentiated ex vivo in the presence of 0.25 μM UNC0638 or the vehicle control. Bar represents 10 μm. (B) Cell proliferation assessed by trypan blue staining in the presence of 3 doses of UNC0638 or the vehicle control (mean ± SD, n = 3 biological replicates). (C) Cell Titer Glo curves for a wide range of UNC0638 concentrations and for 3 different treatment duration (mean ± SD, n = 5-6 biological replicates). (D) Flow cytometry analysis of cell-surface differentiation marker expression at day 15 of erythroid differentiation (mean ± SD, n = 3-4 biological replicates). *P < .05; **P < .01.