Figure 4.

Representative flow cytometric DNA profiles, of asynchronously growing U2OS cells silenced for RB and p53, and untreated (–ActD) or treated (+ActD) with ActD for 1 h and analysed 13 h after the end of the drug treatment. Comparrison between the profiles of cells transfected with the scrambled sequences show an accumulation of cells in G₀/G₁ phase and a marked reduction of cells in S phase after ActD treatment. No significant differences are visible between the profiles of untreated and ActD‐treated cells, silenced for both RB and TP53. Comparison between the profiles of cells silenced for RB show a moderate increase of the percentage of cells in G₂ + M phase after ActD treatment. The same change appears to occur in cells silenced for TP53 after ActD treatment. The values of the percentage of the cells in the cell cycle phases reported in the upper right were the mean of measurements of at least three samples.