Nanosecond Electric Pulses Induce Early and Late Phases of DNA Damage and Cell Death in Cisplatin-Resistant Human Ovarian Cancer Cells

Figure 1

Percentages of dead cells (a) and of comet-formed cells in the alkaline assay (b) after nsEP treatments: the negative death fraction demonstrated proliferation of control cells; two peak levels were detected at 2 and 8 h, with the highest value at 8 h; the value in COC1 cells was higher than that in COC1/DDP cells. Percentage of comet-formed cells in the neutral assay (c): the value was increased at 8 h. Images under the alkaline assay (d): more comets were observed at 2 and 8 h in both cell lines; few comets emerged at 24 h, indicating repair. Images under the neutral assay (e): comets appeared at 8 h, demonstrating single-strand break at 2 h and double-strand break at 8 h. Data were mean ± standard deviation for 3 independent experiments. The scale bar was 50 μm; (a) versus control, p<0.05; (b) versus 2 h, p<0.05; and (c) versus COC1 at the same time point, p<0.05.

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