Figure 2. The profiles of cell cycle phases in ribavirin-treated cells.

HepG2 cells were treated with the (A) indicated doses of ribavirin (0∼100 µg/ml) for 24 h, or (B) with the 100 µg/ml ribavirin for indicated periods of time (0∼48 h). Cells were stained with propidium iodide and then subject to flow cytometric analysis to determine the effect of ribavirin on cell cycle distribution. The percentage of cells in G1, S, and G2/M phase of cell cycle and the percentage of cells in sub-G1 (apoptosis) peak were calculated using CellQuest software. Cells were also analyzed by immunoblotting for the cell cycle regulators: cdk2 and cyclin E. Indicated values are means ± s.e.m of three independent experiments, in each of which triplicate samples were measured. The G1 population of each group was compared to those of the reference groups which are untreated cells in (A) and 0 hour in (B). ^*, p = 0.04, ^**, p<0.01. RBV: ribavirin.