title: Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells.
abstract: Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.
authors.affiliation: Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Morotomi-Yano
authors.forename: Hidenori
authors.initials: H
authors.lastname: Akiyama
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yano
mesh_terms: D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000502:physiology* / Q000528:radiation effects; D002470:Cell Survival; D004560:Electricity; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D009336:Necrosis; D000071137:Poly (ADP-Ribose) Polymerase-1; D011064:Poly Adenosine Diphosphate Ribose / Q000096:biosynthesis*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D011064:Poly Adenosine Diphosphate Ribose; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; D053148:Caspase 3
keywords: Apoptosis; Nanosecond pulsed electric field; Necrosis; PAR; PARP-1; Poly(ADP-ribose); Poly(ADP-ribose) polymerase-1; nanosecond pulsed electric field; nsPEF; poly(ADP-ribose); poly(ADP-ribose) polymerase-1