Actin, tubulin, and Eg5 inhibitors block cell division of human CFU-E. Human CFU-E were cultured for the indicated periods in the presence of EPO with or without various concentrations of inhibitors for actin polymerization (cytochalasin D and NSC23766), tubulin (colchicine) and Eg5 (monastrol). (A) Effects of inhibitors and vehicle on the proliferation of CFU-E. Results presented are the mean ± SD of 3 independent experiments. (B) Cell cycle analysis of cells cultured for 24 hours with (red areas) or without (solid lines) 10μg/mL cytochalasin D, 200μM NSC23766, 10 μg/mL colchicine and 100μM monastrol. A representative result of 3 independent experiments is shown and is presented as the mean ± SD (C) May-Grünwald-Giemsa staining of cells cultured for 24 and 48 hours with or without 10 μg/mL cytochalasin D, 200μM NSC23766, 10 μg/mL colchicine and 100μM monastrol. A representative result of 3 independent experiments is shown. Scale bar = 10 μm.