Abstract
We discuss the death process of human cervical cancer cells HeLa S3 induced by two types of non-thermal intense electrical pulses of different durations and amplitudes, 120 ns-long, 12.5 kV/cm and 5 ns-long, 250 kV/cm. WST-8 assay was used to evaluate the cell viability. Expression of three proteins associated with the stress response, Caspase 3, ASK1 and BAX, were analyzed by using the antibody assay and flowcytometry. Apoptosis activity was evaluated by means of the TUNEL assay and flowcytometry. Also, Ca2+ dependences 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 Ca2+ 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 Ca2+, whereas the death was Ca2+ dependent.
