[Relationship between polymerase eta expression and DNA damage-tolerance in human hepatic cells by hydroquinone].
OBJECTIVE
To investigate the effects of hydroquinone (HQ) on expression of Polymerase eta (Pol eta) and DNA damage in human hepatic cells (L-02), and to explore the role and possible mechanism of Pol eta involved in the process of DNA damage-tolerance.


METHODS
After L-02 hepatic cells were exposed to HQ with various concentrations (0, 5, 10, 20, 40, 80 and 160 micromol/L) for 24 h, cell survival rate was detected by MTT assay; DNA impairment was detected by single cell gel electrophoresis (SCGE); Real-time fluorescent quantitative PCR and Western blotting methods were used to measure the expression of Pol eta at the mRNA and protein level in L-02 hepatic cells exposed to HQ with various concentrations (0, 5, 10, 20, 40, 80 and 160 micromol/L).


RESULTS
MTT assay showed that HQ with concentrations from 0 to 80 micromol/L had little effect on the survival rate of L-02 (P>0.05); whereas the survival rate of the group of 160 micromol/Lwas significantly higher than that of the control (P<0.01) after being treated with HQ for 24 h; the higher dose of HQ presented, the more degrees of DNA damage were produced. It was found that HQ in a low concentration (1-80 micromol/L) could induce the expression of Pol eta which was in proportion to the increasements of HQ concentration; the expression levels of mRNA and protein were reached to the maximum when treated with 80 micromol/L; the expression of Pol eta decreased (the relative quantity values were 2.32 +/- 0.16 and 1.20 respectively) once the concentration of HQ exceeded 160 micromol/L as compared with the group of 80 micromol/L, but it was higher than that of the control.


CONCLUSIONS
This study suggested that Pol eta might involve in the process of DNA damage-tolerance induced by HQ in the hepatic cells.
Hu
Gong-hua
GH
Department of Preventive Medicine, Gannan Medical College, Ganzhou 341000, China.
Zhuang
Zhi-xiong
ZX
Huang
Hai-yan
HY
Yu
Lei
L
Yang
Lin-qing
LQ
Ji
Wei-dong
WD
D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects*; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006873:Hydroquinones / Q000009:adverse effects*; D009153:Mutagens; D000099270:Y-Family DNA Polymerases
D004259:DNA-Directed DNA Polymerase; D006873:Hydroquinones; D009153:Mutagens; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases; C031927:hydroquinone