title: Poly(ADP-ribosyl)ation is a survival mechanism in cigarette smoke-induced and hydrogen peroxide-mediated cell death.
abstract: Cigarette smoking can contribute to the development of many human diseases such as cardiovascular disease, lung cancer, asthma, and chronic obstructive pulmonary disease. Thousands of compounds are present in cigarette smoke, including a large number of reactive oxygen species that can cause DNA damage, leading to the activation of poly(ADP-ribose) polymerase (PARP) enzymes. The PAR polymer is degraded by poly(ADP-ribose) glycohydrolase (PARG). Here we have investigated the effects of cigarette smoke extract (CSE) on A549 human lung epithelial cells. CSE induced DNA damage (comet assay), PAR accumulation (immunofluorescence and immunoblotting), impaired proliferation (clonogenic survival assay and electric cell-substrate impedance sensing measurement), and cell death (MTT reduction, propidium iodide uptake, lactate dehydrogenase release). CSE-induced cell death was also characterized by mitochondrial depolarization but massive translocation of apoptosis-inducing factor could not be observed. To investigate the role of PARylation in CSE-induced oxidative stress, PARP-1- and PARG-silenced A549 cells were used. Silencing of both PARP-1 and PARG sensitized cells to CSE-induced toxicity: PARP-1- and PARG-silenced cell lines exhibited reduced clonogenic survival, displayed a delayed repair of DNA breaks, and showed higher levels of cytotoxicity. CSE triggered the production of mitochondrial superoxide and hydrogen peroxide. Addition of superoxide dismutase increased, whereas catalase abolished, CSE-induced PAR formation. In summary, our data show that the superoxide-hydrogen peroxide-DNA breakage pathway activates the PAR cycle by PARP-1 and PARG, which serves as a survival mechanism in CSE-exposed cells. Our data also raise the possibility that the PARP-1/PARG status of smokers may be an important determinant of the efficiency of DNA repair in their lungs and of their susceptibility to CS-induced carcinogenesis.
authors.affiliation: Department of Medical Chemistry, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Kovács
authors.forename: Katalin
authors.initials: K
authors.lastname: Erdélyi
authors.forename: Csaba
authors.initials: C
authors.lastname: Hegedűs
authors.forename: Petra
authors.initials: P
authors.lastname: Lakatos
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Regdon
authors.forename: Péter
authors.initials: P
authors.lastname: Bai
authors.forename: György
authors.initials: G
authors.lastname: Haskó
authors.forename: Eva
authors.initials: E
authors.lastname: Szabó
authors.forename: László
authors.initials: L
authors.lastname: Virág
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D004249:DNA Damage; D055785:Gene Knockdown Techniques; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D012906:Smoke; D014026:Nicotiana / Q000737:chemistry*
chemical_list: D016877:Oxidants; D011506:Proteins; D017382:Reactive Oxygen Species; D012906:Smoke; C024857:poly(ADP)-ribosylated proteins; D011064:Poly Adenosine Diphosphate Ribose; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase