Study type: Medical/biological study (experimental study)

Nanosecond pulsed electric fields (nsPEF) induce direct electric field effects and biological effects on human colon carcinoma cells. med./bio.

Published in: DNA Cell Biol 2005; 24 (5): 283-291

Aim of study (acc. to author)

To study the role of p53 during nanosecond pulsed electric fields (nsPEF) exposure.

Background/further details

Colon carcinoma cells (HCT116p53+/+ and p53-/-) were used, providing a knockout cell line that specifically tests the role of p53.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
  • unspecified
Modulation type: single pulse
Exposure 2:
  • unspecified
Modulation type: single pulse

Exposure 1

Main characteristics
Frequency
  • unspecified
Type
Waveform
Modulation
Modulation type single pulse
Pulse width 60 ns
Additional info

1, 3 or 5 pulses were applied.

Exposure setup
Exposure source
  • pulse generators with 10-Ω impedance [Schoenbach et al., 2001]
Setup Cells in Hanks balanced salt solution were placed in 0.1-cm gap Bio-Rad gene Pulser® cuvettes.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 60 kV/cm maximum - - 16, 26, 40, 60 kV/cm

Exposure 2

Main characteristics
Frequency
  • unspecified
Type
Waveform
Modulation
Modulation type single pulse
Pulse width 300 ns
Additional info

1, 3 or 5 pulses were applied.

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 60 kV/cm maximum - - 12, 18, 26, 40, 60 kV/cm

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data indicate direct electric field effects on the HCT116 colon carcinoma cells as well as biological responses from the cells that are dependent and independent of p53. Exposure to nsPEF reveals p53-dependent actions on cell survival including effects on the plasma membrane.
Decreasing plasma membrane effects were revealed in both HCT116p53+/+ and p53-/- cells with decreasing pulse durations and/or decreasing electric field strengths. However, addition of ethidium homodimer-1 (to measure plasma membrane permeability/integrity) and Annexin-V-FITC (indicates the phosphatidylserine externalization) post-pulse produced greater fluorescence in p53-/- versus p53+/+ cells, suggesting a post-pulse p53-dependent biological effect at the plasma membrane.
Caspase activity was significantly higher only in the p53-/- cells.
HCT116 cells exhibited greater survival in response to nsPEFs than HL-60 cells and Jurkat cells, but survival was more evident for HCT116p53+/+ cells than for HCT116p53-/- cells.

Study character:

Study funded by

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