Chemoresistance is a challenge for management of ovarian cancer, and therefore the response of resistant cells to nanosecond\nelectric pulses (nsEP) was explored. Human ovarian cancer cell line COC1 and the cisplatin-resistant subline COC1/DDP were\nsubjected to nsEP (32 ns, 10 kV/cm, 10Hz pulse repletion frequency, and 10min exposure duration), and then the cellular responses\nwere followed. Thepercentages of dead cells and of comet-formed cells in the alkaline assay displayed two peak levels (i.e., 2 and 8 h\nafter nsEP exposure), with the highest value noted at 8 h; the percentage of comet-formed cells in the neutral assay was increased\nat 8 h; the apoptotic percentage was increased at 8 h, with collapse of the mitochondrial membrane potential and the activation\nof caspase-3 and caspase-9. The comet assay demonstrated DNA single-strand break at 2 h and double-strand break at 8 h. nsEP\nresulted in lower cytotoxicity in COC1/DDP cells compared with COC1 cells. These findings indicated that nsEP induced early\nand late phases of DNA damage and cell death, and these two types of cell death may have distinct applications to treatments of\nchemoresistant ovarian cancers.
Loading....