UCN-01 treatment in hepatoma cells resulted in significant S phase and G2/M arrest. Representative flow cytometric graphs are shown of cells treated with different concentrations of UCN-01 for 72 h. (A) Flow cytometry profiles of hepatoma cells are shown. Cell treatments were as follows: DMSO only and UCN-01 30 nM, 100 nM, and 300 nM. (B) The percentage of cells in G1, S, and G2/M phases illustrates that hepatoma cells accumulate in the S and G2/M phases after 300 nM UCN-01 treatment. The UCN-01-treated cells and untreated cells that differ significantly are indicated by and asterisk (P < 0.05).