The effect of Ara-C on proliferation and differentiation of 32D/WT cells. (A) G-CSF– and IL-3–dependent proliferation of 32D/WT cells in the absence or presence of Ara-C. The numbers of viable cells were determined on the basis of trypan blue exclusion at the indicated times. (□) G-CSF; (▪) G-CSF + Ara-C; (▵) IL-3; (▾) IL-3 + Ara-C. (B) Cell cycle distribution of 32D/WT cells cultured for 3 days in G-CSF– or IL-3–containing medium in the absence or presence of Ara-C. The percentages of cells in the G1, S, and G2/M phases of the cell cycle are given in the upper right of the panels. (C) Morphology of 32D/WT cells cultured for 3 days in G-CSF– or IL-3–containing medium in the presence of Ara-C (May-Grünwald-Giemsa staining; original magnification × 630). (D) The percentages of terminally differentiated 32D/WT cells cultured in G-CSF– or IL-3–containing medium in the absence or presence of Ara-C. At least 200 cells were scored at the indicated times. Symbols are the same as in (A).