title: Nanosecond pulsed electric fields (nsPEF) induce direct electric field effects and biological effects on human colon carcinoma cells.
abstract: Nanosecond pulsed electric fields (nsPEFs) are ultrashort pulses with high electric field intensity (kV/cm) and high power (megawatts), but low energy density (mJ/cc). To determine roles for p53 in response to nsPEFs, HCT116 cells (p53+/+ and p53-/-) were exposed to nsPEF and analyzed for membrane integrity, phosphatidylserine externalization, caspase activation, and cell survival. Decreasing plasma membrane effects were observed in both HCT116p53+/+ and p53-/- cells with decreasing pulse durations and/or decreasing electric fields. However, addition of ethidium homodimer-1 and Annexin-V-FITC post-pulse demonstrated greater fluorescence in p53-/- versus p53+/+ cells, suggesting a postpulse p53-dependent biological effect at the plasma membrane. Caspase activity was significantly higher than nonpulsed cells only in the p53-/- cells. HCT116 cells exhibited greater survival in response to nsPEFs than HL-60 and Jurkat cells, but survival was more evident for HCT116p53+/+ cells than for HCT116p53-/- cells. These results indicate that nsPEF effects on HCT116 cells include (1) apparent direct electric field effects, (2) biological effects that are p53-dependent and p53-independent, (3) actions on mechanisms that originate at the plasma membranes and at intracellular structures, and (4) an apparent p53 protective effect. NsPEF applications provide a means to explore intracellular structures and functions that can reveal mechanisms in health and disease.
authors.affiliation: Center for Pediatric Research, Eastern Virginia Medical School, Children's Hospital of the King's Daughters, Norfolk, Virginia 23510, USA.
authors.forename: Emily H
authors.initials: EH
authors.lastname: Hall
authors.forename: Karl H
authors.initials: KH
authors.lastname: Schoenbach
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Beebe
mesh_terms: D017304:Annexin A5; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism* / Q000528:radiation effects*; D002467:Cell Nucleus / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D004789:Enzyme Activation; D004996:Ethidium / Q000031:analogs & derivatives* / Q000494:pharmacology; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins / Q000378:metabolism; D045325:HCT116 Cells; D018922:HL-60 Cells; D006801:Humans; D006834:Hydrazines; D007364:Intercalating Agents / Q000494:pharmacology; D019169:Jurkat Cells; D018613:Microscopy, Confocal; D010718:Phosphatidylserines / Q000032:analysis; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: C417561:Alexa 488 hydrazide; D017304:Annexin A5; D061945:Caspase Inhibitors; D005456:Fluorescent Dyes; D006834:Hydrazines; D007364:Intercalating Agents; D010718:Phosphatidylserines; D016159:Tumor Suppressor Protein p53; D049452:Green Fluorescent Proteins; C018533:ethidium homodimer; D020169:Caspases; D004996:Ethidium; D016650:Fluorescein-5-isothiocyanate