title: A DNA-dependent stress response involving DNA-PK occurs in hypoxic cells and contributes to cellular adaptation to hypoxia.
abstract: DNA-dependent protein kinase (DNA-PK) is involved in DNA double-strand break (DSB) signalling and repair. We report that DNA-PK is activated by mild hypoxia conditions (0.1-1% O₂) as shown by (1) its autophosphorylation on Ser2056, and (2) its mobilisation from a soluble nucleoplasmic compartment to a less extractable nuclear fraction. The recruitment of DNA-PK was not followed by activation and recruitment of the XRCC4-DNA-ligase-IV complex, suggesting that DSBs are not responsible for activation of DNA-PK. To unravel the mechanism of DNA-PK activation, we show that exposure of cells to trichostatin A, a histone deacetylase inhibitor, leads to DNA-PK autophosphorylation and relocalisation to DNA. Histone acetylation (mainly H3K14) is increased in hypoxic cells and treatment with anacardic acid, an inhibitor of histone acetyl transferase, prevented both histone modifications and DNA-PK activation in hypoxic conditions. Importantly, in using either silenced DNA-PK cells or cells exposed to a specific DNA-PK inhibitor (NU7026), we demonstrated that hypoxic DNA-PK activation positively regulates the key transcription factor HIF-1 and one subsequent target gene, GLUT1. Our results show that hypoxia initiates chromatin modification and consequently DNA-PK activation, which positively regulate cellular oxygen-sensing and oxygen-signalling pathways.
authors.affiliation: CNRS-IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Bouquet
authors.forename: Marielle
authors.initials: M
authors.lastname: Ousset
authors.forename: Denis
authors.initials: D
authors.lastname: Biard
authors.forename: Frédérique
authors.initials: F
authors.lastname: Fallone
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Dauvillier
authors.forename: Philippe
authors.initials: P
authors.lastname: Frit
authors.forename: Bernard
authors.initials: B
authors.lastname: Salles
authors.forename: Catherine
authors.initials: C
authors.lastname: Muller
mesh_terms: D000107:Acetylation; D000222:Adaptation, Physiological; D000617:Aminoglycosides / Q000494:pharmacology; D034961:Antigens, Nuclear / Q000378:metabolism; D015687:Cell Hypoxia; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D002867:Chromones / Q000494:pharmacology; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D053281:Enediynes / Q000494:pharmacology; D004789:Enzyme Activation; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D000072200:Ku Autoantigen; D009025:Morpholines / Q000494:pharmacology; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D015398:Signal Transduction; D013312:Stress, Physiological
chemical_list: C479235:2-(morpholin-4-yl)benzo(h)chromen-4-one; D000617:Aminoglycosides; D034961:Antigens, Nuclear; D002843:Chromatin; D002867:Chromones; D004268:DNA-Binding Proteins; D053281:Enediynes; D051272:Glucose Transporter Type 1; D006657:Histones; D006877:Hydroxamic Acids; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009025:Morpholines; C495677:SLC2A1 protein, human; C055955:calicheamicin gamma(1)I; C012589:trichostatin A; D051747:DNA-Activated Protein Kinase; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen