Heat Shock Protein 70 Protects Against DNA Damage of A549 Cells Caused by Benzo(a)pyrene

[Objective] To investigate whether HSP70 plays a role in the protection against DNA damage by B(a)P. [Methods] The A549 cells were transfected with the recombinant pcDNA3.0 plasmid containing HSP70 cDNA as test group. Control cells were transfected with pcDNA3.0 plasmid without HSP70 cDNA but still containing the neomycin resistance gene. Transfected A549 with empty pcDNA3.0 (A549/pcDNA cells) and HSP70 overexpressing A549 cells (A549/HSP70 cells) were exposed to different concentrations of benzo(a)pyrene [1, 5, 10, 50, 100μmol/L B(a)P]. DNA damage was detected with alkaline single-cell gel electrophoresis, and the cell viability was measured by MTT assay. [Results] A549/HSP70 cells had a significant increased viability compared with A549 cells (P 0.05) in high concentrations of B(a)P (50, 100μmol/L). There were dose-dependent increases in DNA damage in all A549, A549/pcDNA and A549/HSP70 cells exposed to B(a)P. The OTM values in A549, A549/pcDNA cells exposed to 1, 5, 10, 50, 100μmol/L B(a)P all increased significantly compared with the groups not exposed to B(a)P, respectively(P 0.05). The OTM values in A549/HSP70 cells exposed to 5, 10, 50,100μmol/L B(a)P increased significantly compared with the group not exposed to B(a)P(P 0.05) .Nevertheless, OTM values in A549/HSP70 cells significantly decreased in B(a)P treatment groups compared to A549 cells with the same treatment of B(a)P(P 0.05), but no marked difference was found in A549/pcDNA cells. [Conclusion] It was suggested that HSP70 has some protection against DNA damage of A549 cells caused by benzo(a)pyrene.