DNA damage, gadd153 expression, and cytotoxicity in plateau-phase renal proximal tubular epithelial cells treated with a quinol thioether

• Published in: Archives of biochemistry and biophysics 1997-05, Vol.341 (2), p.300
• Main Authors: Jeong, J K, Dybing, E, Søderlund, E, Brunborg, G, Holme, J A, Lau, S S, Monks, T J
• Format: Article
• Language: English
• Subjects: Animals; Aurintricarboxylic Acid - pharmacology; Benzamides - pharmacology; Catalase - pharmacology; CCAAT-Enhancer-Binding Proteins; Cell Line; Cell Survival; Chelating Agents - pharmacology; Cytarabine - pharmacology; DNA Damage; DNA Repair - drug effects; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - genetics; Endodeoxyribonucleases - antagonists & inhibitors; Endodeoxyribonucleases - physiology; Enzyme Activation - drug effects; Enzyme Inhibitors - pharmacology; Gene Expression Regulation - drug effects; Glutathione - analogs & derivatives; Glutathione - pharmacology; Glutathione - toxicity; Histones - biosynthesis; Histones - genetics; Hydrogen Peroxide - metabolism; Hydroquinones - pharmacology; Hydroquinones - toxicity; Hydroxyl Radical - metabolism; Hydroxyurea - pharmacology; Kidney Tubules, Proximal - drug effects; Poly(ADP-ribose) Polymerases - physiology; Reactive Oxygen Species - metabolism; Stress, Physiological - chemically induced; Stress, Physiological - genetics; Swine; Transcription Factor CHOP; Transcription Factors - biosynthesis; Transcription Factors - genetics
• ISSN: 0003-9861
• DOI: 10.1006/abbi.1997.9969

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.