Lloyd, Daniel R., Hanawalt, Philip C. (2002) p53 Controls Global Nucleotide Excision Repair of Low Levels of Structurally Diverse Benzo(g)chrysene-DNA Adducts in Human Fibroblasts. Cancer Research, 62 (18). pp. 5288-5294. ISSN 0008-5472. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:10135)
The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. |
Abstract
Benzo(g)chrysene is a widespread environmental contaminant and potent carcinogen. We have measured the formation and nucleotide excision repair of covalent DNA adducts formed by the DNA-reactive metabolite of this compound in human fibroblasts, in which expression of the p53 tumor suppressor gene could be controlled by a tetracycline-inducible promoter. Cells were exposed for 1 h to 0.01, 0.1, or 1.2 microM (+/-)-anti-benzo(g)chrysene diol-epoxide, and DNA adducts were assessed at various post-treatment times by subjecting isolated DNA to (32)P-postlabeling analysis. Four major DNA adducts were detected, corresponding to the reaction of either the (+)- or (-)-anti-benzo(g)chrysene diol-epoxide stereoisomer with adenine or guanine. Treatment with 1.2 microM resulted in a level of 1100 total adducts/10(8) nucleotides for both p53-proficient and -deficient cells; removal of adducts was not observed in either case. In cells treated with 0.1 microM, the maximum level of total adducts at 24 h was 150/10(8) nucleotides in p53-proficient cells and 210 adducts/10(8) nucleotides in p53-deficient cells. A concentration of 0.01 microM resulted in a maximum of 20 adducts/10(8) nucleotides in p53-proficient cells at 4 h, but 40 adducts/10(8) nucleotides persisted in p53-deficient cells at 24 h. Whereas there were clear differences in the time course of adduct levels in p53-proficient compared with p53-deficient cells treated with 0.1 microM or 0.01 microM, these levels did not decrease extensively over 3 days. This is likely because of the stabilization of the diol-epoxide in cells, and consequent exposure and formation of adducts for many hours after the initial treatment. Furthermore, despite minor quantitative differences, all 4 of the adducts behaved similarly with respect to the effect of p53 expression on their removal. p53 appears to minimize the appearance of benzo(g)chrysene adducts in human cells by up-regulating global nucleotide excision repair and reducing the maximum adduct levels achieved. The fact that this p53-dependent effect is noted at levels of DNA adducts that are commonly found in human tissues (i.e., <100 adducts/10(8) nucleotides) because of environmental factors such as smoking is particularly significant with respect to human carcinogenesis related to environmental exposure.
Item Type: | Article |
---|---|
Subjects: | Q Science |
Divisions: | Divisions > Division of Natural Sciences > Biosciences |
Depositing User: | Dan Lloyd |
Date Deposited: | 20 Oct 2008 10:43 UTC |
Last Modified: | 16 Nov 2021 09:48 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/10135 (The current URI for this page, for reference purposes) |
- Export to:
- RefWorks
- EPrints3 XML
- BibTeX
- CSV
- Depositors only (login required):