Comparative synchronous fluorescence spectrophotometry and 32P-postlabelling analysis of PAH-DNA adducts in human lung and the relationship to TP53 mutations

Abstract

Polycyclic aromatic hydrocarbon (PAH)-DNA adducts were studied in human lung from 39 lung cancer patients by synchronous fluorescence spectrophotometric (SFS) and ³²P-postlabelling assays. Regression analysis of the samples failed to detect any correlation between benzo[a]pyrene-diolepxide (BPDE)-DNA adducts detected by SFS and the BPDE co-migrating spot detected by ³²P-postlabelling. We have also analyzed the relationship between adduct levels and TP53 mutations. By postlabelling diagonal radioactive zone (DRZ) adducts were detected in 37 of 39 (95%) lung tissues from lung cancer patients and the adduct level ranged from 6.81 to 108.50 adducts/10⁸ nucleotide. Thirty-three of 39 (85%) had detectable levels of BPDE-DNA adducts (>1 adduct/10⁹ nucleotide). Current heavy smokers (>20 cigarettes/day) have significantly higher DRZ adduct levels compared to individuals smoking less than 20 cigarettes/day. By SFS combined with immunoaffinity column (IAC), 11 of 39 928%) samples had detectable adduct levels, and 6 of 11 (55%) were detectable by SFS following purification of benzo[a]pyrene (BP)-tetrols by high pressure liquid samples were positive for BPDE-DNA adducts by both postlabelling and HPLC/SFS. No correlation was observed between the SFS and ³²P-postlabelling assays for the detection of BPDE-DNA adducts. However, there was a good correlation between adduct levels detected by IAC/SFS and HPLC/SFS. We found a weak association between total PAH-DNA adduct levels in lung tissue and TP53 mutations.