CaSki, SiHa, HeLa, and C33A cervical cancer cells display differential responses to treatment with DOX (a) and cisplatin (b), as well as different baseline levels and distributions of ROS (c and d). (a and b) SiHa, CaSki, HeLa, and C33A cells (1 × 104 cells per well) were seeded into a 96-well plate, allowed to incubate overnight, and then treated with the indicated concentrations of DOX (a) or cisplatin (b) for 48 h. Viability was measured by crystal violet staining and the viability of untreated cells was set at 100%. Each measurement was done in triplicate and error bars indicate the standard deviations of the means. (c and d) 105 cells of each line was treated with 10 μM DCFDA or 10 μM DHE in media and then incubated in the dark at 37°C for 30 minutes. The cells were then washed, and following trypsinization were resuspended in 1x PBS and were analysed by flow cytometry. A total of 10 000 events were measured per sample. (c) DCFDA was detected in the FL-1 channel, while DHE was detected in the FL-2 channel. (d) Bar graphs show triplicate measurements of mean fluorescence intensity of DCFDA or DHE in SiHa, CaSki, HeLa, and C33A cells. Error bars represent the standard deviation.