title: Oxidative stress response results in increased p21WAF1/CIP1 degradation in cystic fibrosis lung epithelial cells.
abstract: Lung epithelium in cystic fibrosis (CF) patients is characterized by structural damage and altered repair due to oxidative stress. To gain insight into the oxidative stress-related damage in CF, we studied the effects of hyperoxia in CF and normal lung epithelial cell lines. In response to a 95% O2 exposure, both cell lines exhibited increased reactive oxygen species. Unexpectedly, the cyclin-dependent kinase inhibitor p21WAF1/CIP1 protein was undetectable in CF cells under hyperoxia, contrasting with increased levels of p21WAF1/CIP1 in normal cells. In both cell lines, exposure to hyperoxia led to S-phase arrest. Apoptotic features including nuclear condensation, DNA laddering, Annexin V incorporation, and elevated caspase-3 activity were not readily observed in CF cells in contrast to normal cells. Interestingly, treatment of hyperoxia-exposed CF cells with two proteasome inhibitors, MG132 and lactacystin, restored p21WAF1/CIP1 protein and was associated with an increase of caspase-3 activity. Moreover, transfection of p21WAF1/CIP1 protein in CF cells led to increased caspase-3 activity and was associated with increased apoptotic cell death, specifically under hyperoxia. Taken together, our data suggest that modulating p21WAF1/CIP1 degradation may have the therapeutic potential of reducing lung epithelial damage related to oxidative stress in CF patients.
authors.affiliation: Inserm U719, Université Pierre et Marie Curie, Hôpital Saint-Antoine, 184 rue du Fg St Antoine, Bâtiment Kourilsky, 75571 Paris Cedex 12, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Boncoeur
authors.forename: Olivier
authors.initials: O
authors.lastname: Tabary
authors.forename: Elise
authors.initials: E
authors.lastname: Bonvin
authors.forename: Celine
authors.initials: C
authors.lastname: Muselet
authors.forename: Asmaa
authors.initials: A
authors.lastname: Fritah
authors.forename: Emilie
authors.initials: E
authors.lastname: Lefait
authors.forename: Gerard
authors.initials: G
authors.lastname: Redeuilh
authors.forename: Annick
authors.initials: A
authors.lastname: Clement
authors.forename: Jacky
authors.initials: J
authors.lastname: Jacquot
authors.forename: Alexandra
authors.initials: A
authors.lastname: Henrion-Caude
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000201:enzymology* / Q000473:pathology; D004847:Epithelial Cells / Q000201:enzymology / Q000473:pathology; D006801:Humans; D018496:Hyperoxia / Q000201:enzymology; D007976:Leupeptins / Q000494:pharmacology; D008168:Lung / Q000201:enzymology* / Q000473:pathology; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016196:S Phase
chemical_list: D017304:Annexin A5; D050759:Cyclin-Dependent Kinase Inhibitor p21; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D017382:Reactive Oxygen Species; C067713:lactacystin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D010100:Oxygen; D000111:Acetylcysteine