Fig. 9. Reduction of p53 expression increased DNA oxidation in SiHa cells. (A) 8-oxo-dG level in SiHa cells expressing negative control plasmid (SiHa/N) or p53 shRNA plasmid (SiHa/sip53) 48 hours after transfection. (B) 48 hours after transfection with negative control plasmid or p53 shRNA plasmid, cells were treated with the indicated concentrations of H₂O₂ for 1 hour. Quantification of 8-oxo-dG staining was performed after FACScan analysis using CellQuest software. 8-oxo-dG levels are expressed as the mean ± s.d. intensity of cell fluorescence. ^*P<0.01 compared with the corresponding cells with negative control vector by Student's t-test.