Dynamic changes of XPA, XPC, XPF, XPG and ERCC1 protein expression and their correlations with levels of DNA damage in human bronchial epithelia cells exposed to benzo[a]pyrene.
Benzo[a]pyrene (BaP) is a ubiquitously distributed environmental pollutant known to cause DNA damage, which may be repaired through nucleotide excision repair (NER). However, little is known about dynamic changes in levels of DNA damage and their correlations with levels of NER proteins in cells exposed to BaP. In a series of experiments using the human bronchial epithelia cells (16HBE) exposed to different concentrations of BaP for different times, we measured dynamic changes in levels of DNA damage and expression of NER subunit xeroderma pigmentosum (XP) groups A, C, F, G (XPA, XPC, XPF, XPG) and excision repair cross-complementing 1 (ERCC1), and analyzed their possible correlations. We found that in vitro exposure to BaP reduced cell viability in a dose-dependent manner ranging from 2 to 64microM and increased DNA damage in a dose- and time-dependent manner. Our results showed that levels of these NER proteins significantly increased and peaked at 12th or 24th, 8th or 12th and 4th or 8th hours in cells exposed to 2, 8 and 16microM BaP, respectively. ERCC1 expression increased by 2.4-, 4.2- and 19.3-fold for exposure to 2, 8 and 16microM BaP, respectively, compared with control group. Moreover, levels of ERCC1 in cells exposed 16microM BaP significantly higher than those in 2 and 8microM BaP from 2nd to 48th hours. In addition, there was a significant positive correlation between Olive tail moments and relative ratios of ERCC1 in cells exposed to BaP. Our results suggested ERCC1 may be an important limiting factor for NER, but the mechanisms underlying this observation needs further investigation.
Yang
Jin
J
Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030 Wuhan, China.
Liu
Xiaoyong
X
Niu
Piye
P
Zou
Yunfeng
Y
Gong
Zhiyong
Z
Yuan
Jing
J
Wu
Tangchun
T
D001564:Benzo(a)pyrene / Q000633:toxicity*; D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004785:Environmental Pollutants / Q000633:toxicity*; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009153:Mutagens / Q000633:toxicity*
D004268:DNA-Binding Proteins; D004785:Environmental Pollutants; D009153:Mutagens; D001564:Benzo(a)pyrene