Cell Death Induced by Nanosecond Pulsed Electric Fields and its Dependence on Pulse Duration

摘要

We discuss the death process of human cervical cancer cells HeLa S3 induced by two types of nonthermal intense electrical pulses of different durations and amplitudes, 120 ns-long, 12.5 kV/cm and 5 ns-long, 250 kV/cm. WST-8 Caspase 3, ASK1 and BAX, were analyzed by using the antibody assay and flow cytometry. Apoptosis activity was evaluated by means of the TUNEL assay and flow cytometry. Also, Ca~(2+) dependence of the death process and the protein expression were explored by using the metal ion chelating agent, EDTA. Our experiments demonstrated that 5 ns and 120 ns pulses give quite different biological stresses leading to the different death process and the protein expressions. The cell death induced by 120 ns pulses are dependent on the presence of Ca~(2+) and accompanied by expression of proteins associated with apoptosis and stress response. Conversely, the protein expression induced by 5 ns pulses was independent of the presence of Ca~(2+), whereas the death was dependent on Ca~(2+).