Induction of apoptosis by ART and radiation in HeLa and SiHa cells. Cells were treated with ART for 24 h prior to treatment with 2 or 6 Gy irradiation. Apoptosis and necrosis were measured using propidium iodide (PI)/annexin-V double staining in (A) Hela and (B) SiHa cells. The data are shown as mean ± SEM for three independent experiments. Statistical analysis between the groups was determined by ANOVA; *P < 0.05.