title: Two modes of cell death caused by exposure to nanosecond pulsed electric field.
abstract: High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF), are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation"), leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr) does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF). These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP) cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.
authors.affiliation: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia, USA. olga@pakhomova.net
authors.forename: Olga N
authors.initials: ON
authors.lastname: Pakhomova
authors.forename: Betsy W
authors.initials: BW
authors.lastname: Gregory
authors.forename: Iurii
authors.initials: I
authors.lastname: Semenov
authors.forename: Andrei G
authors.initials: AG
authors.lastname: Pakhomov
mesh_terms: D017209:Apoptosis; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival; D055664:Electrochemical Techniques; D006801:Humans; D015151:Immunoblotting; D009336:Necrosis; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis; D013395:Sucrose / Q000378:metabolism; D020298:U937 Cells
chemical_list: D013395:Sucrose; D011065:Poly(ADP-ribose) Polymerases
references.citation: Biochim Biophys Acta. 2010 Nov;1800(11):1210-9
references.pmid: 20691249
references.citation: DNA Cell Biol. 2005 May;24(5):283-91
references.pmid: 15869405
references.citation: Physiol Meas. 2004 Aug;25(4):1077-93
references.pmid: 15382843
references.citation: Biochem Biophys Res Commun. 2006 May 5;343(2):351-60
references.pmid: 16545779
references.citation: PLoS One. 2012;7(8):e43891
references.pmid: 22937117
references.citation: J Membr Biol. 2010 Jul;236(1):15-26
references.pmid: 20623351
references.citation: Int J Cancer. 2007 Aug 1;121(3):675-82
references.pmid: 17417774
references.citation: Biophys J. 2004 Jun;86(6):4040-8
references.pmid: 15189899
references.citation: DNA Cell Biol. 2003 Dec;22(12):785-96
references.pmid: 14683589
references.citation: Bioelectromagnetics. 2001 Sep;22(6):440-8
references.pmid: 11536285
references.citation: Technol Cancer Res Treat. 2011 Jun;10(3):281-6
references.pmid: 21517135
references.citation: Nature. 1977 Aug 4;268(5619):438-41
references.pmid: 895849
references.citation: Mutat Res. 2003 Dec 9;542(1-2):65-75
references.pmid: 14644355
references.citation: PLoS One. 2012;7(8):e43213
references.pmid: 22927951
references.citation: Cell Death Differ. 1998 Feb;5(2):183-90
references.pmid: 10200463
references.citation: BMC Cell Biol. 2006 Oct 19;7:37
references.pmid: 17052354
references.citation: J Biol Chem. 1998 Mar 20;273(12):6603-6
references.pmid: 9506954
references.citation: Biochim Biophys Acta. 1977 Dec 1;471(2):227-42
references.pmid: 921980
references.citation: Technol Cancer Res Treat. 2012 Feb;11(1):83-93
references.pmid: 22181334
references.citation: Biochim Biophys Acta. 2011 Mar;1808(3):792-801
references.pmid: 21182825
references.citation: Cancer Metastasis Rev. 2011 Mar;30(1):61-9
references.pmid: 21249425
references.citation: Biophys J. 2003 Apr;84(4):2709-14
references.pmid: 12668479
references.citation: Cell Biochem Biophys. 2004;41(2):233-58
references.pmid: 15475611
references.citation: J Immunol Methods. 1995 Sep 25;185(2):249-58
references.pmid: 7561136
references.citation: Biochem Biophys Res Commun. 2012 May 18;421(4):808-12
references.pmid: 22554515
references.citation: Bioelectromagnetics. 2006 Apr;27(3):221-5
references.pmid: 16342277
references.citation: PLoS One. 2011 Jan 26;6(1):e15642
references.pmid: 21390200
references.citation: Apoptosis. 2011 Apr;16(4):382-93
references.pmid: 21213047
references.citation: Bioelectrochemistry. 2010 Aug;79(1):95-100
references.pmid: 20097138
references.citation: Cancer Res. 1993 Sep 1;53(17):3976-85
references.pmid: 8358726
references.citation: Int J Cancer. 2009 Jul 15;125(2):438-45
references.pmid: 19408306
references.citation: Arch Biochem Biophys. 2007 Sep 1;465(1):109-18
references.pmid: 17555703
references.citation: Phys Biol. 2006 Nov 02;3(4):233-47
references.pmid: 17200599
references.citation: Biochim Biophys Acta. 1999 Aug 18;1439(3):317-30
references.pmid: 10446420
references.citation: FASEB J. 2011 Sep;25(9):3250-61
references.pmid: 21659556
references.citation: PLoS One. 2011 Feb 09;6(2):e17100
references.pmid: 21347394
references.citation: FASEB J. 2003 Aug;17(11):1493-5
references.pmid: 12824299