title: Intense nanosecond pulsed electric fields promote cancer cell apoptosis through centrosome-dependent pathway involving reduced level of PLK1.
abstract: BACKGROUND
  Intense nanosecond pulsed electric fields (nsPEFs) have been known to promote apoptosis without physically changing membrane structure or damaging morphology of tumor cells. To determine the contribution of centrosome to the progression of apoptosis by nsPEFs, HeLa cells were exposed to high intensity (6 kV/cm) nsPEFs (8-32 ns) in normal culture condition and cell biology and molecular parameters of cells were investigated.
  
  
  METHODS
  Apoptotic cell death was identified by TUNEL assay after being exposed to the nsPEFs with various pulse durations, while immunofluorescent staining was performed to detect the number and distribution of centrosomes. To clarify whether nsPEFs-induced centrosome over-duplication is the consequence of DNA damage, we used comet assay to detect simultaneous DNA damage. And additionally Western Blot was used to detect PLK1 protein level to explore the correlation between apoptotic cell death and nsPEFs-induced centrosome over-duplication. Correlation between nsPEFs and molecular parameters was statistically analyzed.
  
  
  RESULTS
  NsPEFs induced a clear apoptosis reaching a maximum at 24ns, 24h after exposure (p < 0.05), where DNA fragmentation and over-duplicated centrosomes were observed. This apoptosis may be promoted in a time- and pulse duration-dependent manner. Polo-like kinase (PLK1) protein levels were significantly decreased by such nsPEFs (p < 0.05). Control treatment without the nsPEFs did not cause any damage to the cultured HeLa cells.
  
  
  CONCLUSIONS
  Intense nsPEFs promote cell apoptosis through a centrosome-mediated pathway involving a reduction in the level of PLK1, which may provide new therapeutic targets for human cancer treatment.
authors: Laboratory of Biomedical Ultrasonics/Gynecological Oncology Laboratory, West China Second University Hospital, Sichuan University, Chengdu, P.R. China.
authors: H
authors: H
authors: Zou
authors: X L
authors: XL
authors: Gan
authors: L J
authors: LJ
authors: Linghu
authors: C
authors: C
authors: Chen
authors: L N
authors: LN
authors: Hu
authors: Y
authors: Y
authors: Zhang
mesh_terms: D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000502:physiology*; D018385:Centrosome / Q000502:physiology*; D004249:DNA Damage; D004599:Electric Stimulation Therapy; D006367:HeLa Cells; D006801:Humans; D009369:Neoplasms / Q000628:therapy*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1