Figure 3.

Inhibition of p21 abolished cell cycle arrest but not ROS induction upon p53 expression. (A–F) EJ cells expressing either a p21 shRNA (shp21) or nontargeting shRNA (shNC) were infected with a p53 adenovirus. EJ cells were harvested at the indicated time points and subjected to Western blot analysis using the indicated antibodies (A). SA‐β‐gal staining was performed after 6 days (B), and a representative image is shown (D). Cell numbers were determined at the indicated time points by trypan blue exclusion (D). The percentage of cells in the S‐phase was examined using an EPICS XL cytometer (E). Intracellular ROS levels were measured at the indicated time points using an EPICS XL cytometer after the staining of cells with DCF‐DA (50 μm) (F). *P < 0.05 by Student's t‐test. NS, not significant.