title: DNA damage, gadd153 expression, and cytotoxicity in plateau-phase renal proximal tubular epithelial cells treated with a quinol thioether.
abstract: 2-Bromo-bis-(glutathion-S-yl)hydroquinone [2-Br-bis-(GSyl)HQ] causes DNA single-strand breaks (SSB), causes growth arrest, induces the expression of gadd153 (a gene inducible by growth arrest and DNA damage), and decreases histone H2B mRNA in log-phase renal proximal tubular epithelial cells (LLC-PK1). Renal epithelial cells in vivo normally exhibit a low mitotic index, therefore experiments in both plateau- and log-phase cells are necessary for a comprehensive understanding of the stress response to 2-Br-bis-(GSyl)HQ. In the present article we demonstrate that not all features of the stress response in log-phase cells are reproduced in plateau-phase cells. Thus, although 2-Br-bis-(GSyl)HQ causes concentration and time-dependent increases in DNA SSB, and increases the expression of gadd153, histone H2B mRNA levels are unaltered in plateau-phase cells. The relationship between reactive oxygen species, DNA damage, gene expression, and cytotoxicity was also investigated. Our findings suggest that (i) 2-Br-bis-(GSyl)HQ-mediated DNA damage in LLC-PK1 cells is mediated by the generation of H2O2; (ii) DNA damage, either directly or indirectly, contributes to cell death; and (iii) DNA damage, either directly or indirectly, provides the initial signal for gadd153 expression. In addition, DNA repair is rapid in LLC-PK1 cells, and the DNA-repair inhibitors 1-beta-D-arabinofuranosylcytosine and hydroxyurea have no effect on the amount of DNA SSB. Although the addition of 3-aminobenzamide following 2-Br-bis-(GSyl)HQ exposure has no effect on the removal of DNA SSB, it causes a slight but significant increase in gadd153 expression and cell viability, indicating that activation of poly(ADP-ribose)polymerase may exacerbate toxicity. Finally, aurintricarboxylic acid did not prevent DNA SSB or cytotoxicity in 2-Br-bis-(GSyl) HQ-treated LLC-PK1 cells, implying that activation of endonucleases does not play a role in these processes.
authors.affiliation: Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin 78712, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Jeong
authors.forename: E
authors.initials: E
authors.lastname: Dybing
authors.forename: E
authors.initials: E
authors.lastname: Søderlund
authors.forename: G
authors.initials: G
authors.lastname: Brunborg
authors.forename: J A
authors.initials: JA
authors.lastname: Holme
authors.forename: S S
authors.initials: SS
authors.lastname: Lau
authors.forename: T J
authors.initials: TJ
authors.lastname: Monks
mesh_terms: D000818:Animals; D001312:Aurintricarboxylic Acid / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology; D022762:CCAAT-Enhancer-Binding Proteins; D002374:Catalase / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival; D002614:Chelating Agents / Q000494:pharmacology; D003561:Cytarabine / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000037:antagonists & inhibitors / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000633:toxicity; D006657:Histones / Q000096:biosynthesis / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D006873:Hydroquinones / Q000494:pharmacology* / Q000633:toxicity; D017665:Hydroxyl Radical / Q000378:metabolism; D006918:Hydroxyurea / Q000494:pharmacology; D007687:Kidney Tubules, Proximal / Q000187:drug effects*; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological / Q000139:chemically induced / Q000235:genetics; D013552:Swine; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D001549:Benzamides; D022762:CCAAT-Enhancer-Binding Proteins; D002614:Chelating Agents; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D006657:Histones; D006873:Hydroquinones; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D003561:Cytarabine; C066791:2-bromo-(diglutathion-S-yl)hydroquinone; D051742:Transcription Factor CHOP; D017665:Hydroxyl Radical; D001312:Aurintricarboxylic Acid; C025160:3-aminobenzamide; D006861:Hydrogen Peroxide; D002374:Catalase; D011065:Poly(ADP-ribose) Polymerases; D004706:Endodeoxyribonucleases; D005978:Glutathione; D006918:Hydroxyurea