In vitro study on role of Hsp70 expression in DNA damage of human embryonic lung cells exposed to Benzo[a]pyrene

Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether H...

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Published inBiomedical and environmental sciences Vol. 17; no. 2; p. 144
Main Authors Gao, Ya-Juan, Xiao, Cheng-Feng, Chen, Sheng, Wang, Rui-Bo, He, Han-Zhen, Tanguay, Robert M, Wu, Tang-Chun
Format Journal Article
LanguageEnglish
Published China 01.06.2004
Subjects
Benzo(a)pyrene
Blotting, Western
Carcinogens, Environmental
Cells, Cultured
Comet Assay
DNA - drug effects
DNA Damage
Dose-Response Relationship, Drug
HSP70 Heat-Shock Proteins - analysis
HSP70 Heat-Shock Proteins - biosynthesis
HSP70 Heat-Shock Proteins - genetics
Humans
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Summary:Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown. We assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay). Exposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent +-increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 micromol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells. These data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.
ISSN:0895-3988