title: Possible role of DNA polymerase beta in protecting human bronchial epithelial cells against cytotoxicity of hydroquinone.
abstract: OBJECTIVE
  To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.
  
  
  METHODS
  DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone (ranged from 10 micromol/L to 120 micromol/L) for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis (SCGE)] were performed respectively to detect the toxicity of hydroquinone.
  
  
  RESULTS
  MTT assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups.
  
  
  CONCLUSIONS
  Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.
authors.affiliation: Department of Preventive Medicine, School of Public Health, SunYat-sen University, Guangzhou 510080, Guangdong, China.
authors.forename: Da-Lin
authors.initials: DL
authors.lastname: Hu
authors.forename: Huan-Wen
authors.initials: HW
authors.lastname: Tang
authors.forename: Hai-Rong
authors.initials: HR
authors.lastname: Liang
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Tang
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Liu
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Ji
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Yuan
authors.forename: Yun
authors.initials: Y
authors.lastname: He
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Zhu
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Yang
authors.forename: Dao-Kui
authors.initials: DK
authors.lastname: Fang
authors.forename: Yan
authors.initials: Y
authors.lastname: Sha
authors.forename: Xiao-Zhi
authors.initials: XZ
authors.lastname: Tu
authors.forename: Zhi-Xiong
authors.initials: ZX
authors.lastname: Zhuang
mesh_terms: D001980:Bronchi / Q000166:cytology / Q000187:drug effects; D002478:Cells, Cultured; D020552:Comet Assay; D003603:Cytotoxins / Q000633:toxicity*; D004249:DNA Damage; D019951:DNA Polymerase beta / Q000037:antagonists & inhibitors / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D006873:Hydroquinones / Q000633:toxicity*; D034622:RNA Interference
chemical_list: D003603:Cytotoxins; D006873:Hydroquinones; D019951:DNA Polymerase beta; C031927:hydroquinone