Table 1 Cell cycle inhibition by pharmacological differentiating agents

U937 cells were incubated alone or in the presence of byrostatin-1 (10 nM) with or without GM-CSF (200 units/ml), hydroxyurea (100 µg/ml), or phenylbutyrate (1.5 mM) for 48 h and then analyzed for cell cycle distribution. Results are provided as the percentage of total cells and represent the mean ± SE of five separate experiments.

Cell cycle phase Control Bryostatin Bryostatin + GM-CSF Hydroxyurea Phenylbutyrate

G0-G1 31.8 ± 1.6 47.7 ± 7.4 48.1 ± 3.2 19.5 ± 2.3 53.9 ± 15
S 61.2 ± 3.3 39.3 ± 16 39.7 ± 5.5 76.3 ± 3.0 39.0 ± 19
G2-M 7.0 ± 1.7 10.2 ± 6.3 12.2 ± 4.1 3.0 ± 0.6 4.4 ± 1.8