title: Non-thermal plasma-induced apoptosis is modulated by ATR- and PARP1-mediated DNA damage responses and circadian clock.
abstract: Non-thermal plasma (NTP) has been emerging as a potential cancer therapeutic. However, the practical use of NTP as a cancer therapy requires a better understanding of the precise mechanisms underlying NTP-induced DNA damage responses in order to achieve optimal efficacy. It has been shown that the addition of oxygen gas flow during NTP treatment (NTPO), when compared to NTP exposure alone, can induce a 2-3 fold greater generation of intracellular reactive oxygen species (ROS) in A549 cells. Here, we examined NTPO-induced DNA damage responses and found that NTPO generated a substantial number of genomic DNA lesions and breaks that activated ATR-mediated cell-cycle checkpoints. In addition, we discovered that NTPO-induced DNA lesions were primarily removed by base excision repair (BER) rather than by nucleotide excision repair (NER). Therefore, the inhibition of the BER pathway using a PARP1 inhibitor drastically induced the phosphorylation of γH2AX, and was followed by the programmed cell death of cancer cells. However, the knock-down of XPA, which inhibited the NER pathway, had no effect on NTPO-induced phosphorylation of γH2AX. Finally, in agreement with a recent report, we found a circadian rhythm of PARP1 activity in normal mouse embryonic fibroblasts that needed for cell viability upon NTPO treatment. Taken together, our findings provided an advanced NTP regimen for cancer treatment by combining NTPO treatment with chemical adjuvants for the inhibition of ATR- and PARP1-activated DNA damage responses, and circadian timing of treatment.
authors.affiliation: Department of Biological Science, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Ji Ye
authors.initials: JY
authors.lastname: Choi
authors.affiliation: Department of Physics, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Hea Min
authors.initials: HM
authors.lastname: Joh
authors.affiliation: Department of Biological Science, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Jeong-Min
authors.initials: JM
authors.lastname: Park
authors.affiliation: Department of Biological Science, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Physics, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Tae Hun
authors.initials: TH
authors.lastname: Chung
authors.affiliation: Department of Biological Science, Dong-A University, Busan 604714, Republic of Korea.
authors.forename: Tae-Hong
authors.initials: TH
authors.lastname: Kang
mesh_terms: D000072283:A549 Cells; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D057906:Circadian Clocks / Q000187:drug effects* / Q000235:genetics; D004249:DNA Damage; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D051379:Mice; D018345:Mice, Knockout; D058626:Plasma Gases / Q000494:pharmacology*; D000071137:Poly (ADP-Ribose) Polymerase-1 / Q000235:genetics / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*
chemical_list: D058626:Plasma Gases; C499320:PARP1 protein, human; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C576897:Atr protein, mouse; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins
keywords: ATR; DNA damage response; PARP1; circadian clock; non-thermal plasma