Possible role of DNA polymerase beta in protecting human bronchial epithelial cells against cytotoxicity of hydroquinone.
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.
Hu
Da-Lin
DL
Department of Preventive Medicine, School of Public Health, SunYat-sen University, Guangzhou 510080, Guangdong, China.
Tang
Huan-Wen
HW
Liang
Hai-Rong
HR
Tang
Dong-Sheng
DS
Liu
Yi-Ming
YM
Ji
Wei-Dong
WD
Yuan
Jian-Hui
JH
He
Yun
Y
Zhu
Zheng-Yu
ZY
Yang
Jian-Ping
JP
Fang
Dao-Kui
DK
Sha
Yan
Y
Tu
Xiao-Zhi
XZ
Zhuang
Zhi-Xiong
ZX
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
D003603:Cytotoxins; D006873:Hydroquinones; D019951:DNA Polymerase beta; C031927:hydroquinone