title: Correlations and co-localizations of Hsp70 with XPA, XPG in human bronchial epithelia cells exposed to benzo[a]pyrene.
abstract: Benzo[a]pyrene (BaP) is a ubiquitously distributed environmental pollutant known to cause DNA damage, which may be repaired through nucleotide excision repair (NER). The significantly negative correlation between Hsp70 levels and the level of DNA damage in workers exposed to coke oven emission had been found. However, little is known about how Hsp70 modulate the DNA repair process. In a series of experiments using the human bronchial epithelia cells (16HBE) exposed to different concentrations of BaP for 24h, we measured expression of NER subunit xeroderma pigmentosum (XP) group A, C, F, G (XPA, XPC, XPF, XPG), excision repair cross-complementing 1 (ERCC1) and Hsp70, and analyzed their possible correlations. Co-localizations of Hsp70 with NER subunit were detected by confocal microscope. We found that in vitro exposure to BaP reduced cell viability in a dose-dependent manner ranging from 2 to 64 microM. Our results showed that levels of XPA, XPG and Hsp70 significantly increased at cells exposed to 1 or 2muM BaP. In addition, curve estimation showed there was a significant correlation between relative ratios of Hsp70 and XPA, XPG in cells exposed to different concentrations of BaP. Moreover, confocal microscopy demonstrated increased co-localization of Hsp70 with XPA, XPG in nuclei of cells exposed to BaP. These results suggested that Hsp70 might play a role in nucleotide excision repair. However, the mechanisms underlying this observation need further investigation.
authors.affiliation: Department of Occupational Health, School of Public Health, Shanxi Medical University, Xinjiannan Road 86, 030001 Taiyuan, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Liu
authors.forename: Piye
authors.initials: P
authors.lastname: Niu
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zou
authors.forename: Yanying
authors.initials: Y
authors.lastname: Duan
mesh_terms: D001564:Benzo(a)pyrene / Q000633:toxicity*; D015153:Blotting, Western; D001980:Bronchi / Q000378:metabolism*; D002273:Carcinogens / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004720:Endonucleases / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D018613:Microscopy, Confocal; D009687:Nuclear Proteins / Q000378:metabolism*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D051760:Xeroderma Pigmentosum Group A Protein / Q000378:metabolism*; D000099250:DNA Excision Repair Protein ERCC-5
chemical_list: D001564:Benzo(a)pyrene; D002273:Carcinogens; D004268:DNA-Binding Proteins; D004720:Endonucleases; D018840:HSP70 Heat-Shock Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D051760:Xeroderma Pigmentosum Group A Protein; D000099250:DNA Excision Repair Protein ERCC-5