Interception of reactive, DNA adduct‐forming metabolites present in rodent serum following carcinogen exposure: Implications for use of body fluids in biomonitoring

Abstract

The detection of adduct-forming metabolites in the serum of carcinogen treated animals by 32P-postlabeling was evaluated as a novel approach to overcome the stringent requirement of obtaining DNA from tissues in human biomonitoring assessments. Benzo[a]pyrene (BP) was given i.p. to B6C3F1, C57B1/6, ICR, and DBA/2 mouse strains as well as Sprague-Dawley rats. Three adducts related to BP were detected in the liver and/or lung of Sprague-Dawley rats or B6C3F1, C57B1/6, and ICR mice; a single adduct was detected in the liver and lung of the DBA/2 mouse strain. Adducts chromatographically similar to those found in these tissues were also detected when salmon sperm DNA was incubated with the serum of BP-treated animals. Benzidine treatment induced the formation of one adduct in the liver of B6C3F1 mice, which was chromatographically similar to dG-C8-N'-acetylbenzidine. An identical adduct was detected in the salmon sperm DNA incubated with the serum of these mice. Cyclopenta[cd]pyrene treatment produced four major and three minor adducts in the liver or lung of B6C3F1 mice, all but two of which were detected in DNA incubated with serum of cyclopenta[cd]pyrene-treated animals. Large interstrain differences in the serum level of BP adduct-forming metabolites as well as tissue DNA adducts were found which correlated with previously observed strain-specific trends in sensitivity to PAH-mediated carcinogenesis. Thus, levels of BP adduct-forming metabolites were found in the following descending order: B6C3F1, C57B1/6, ICR, and DBA/2. BP-derived adduct-forming metabolites were detectable as late as 2 d and 5 d post-treatment in the serum of C57B1/6 mice or Sprague-Dawley rats, respectively, which seems to coincide well with the reported species-specific turnover of serum albumin; a protein know to be involved in the transport of reactive metabolites throughout the systemic circulation. The results obtained clearly indicate the presence of adduct-forming carcinogen metabolites in the serum of treated animals, which seemingly irrespective of their chemical nature, can be intercepted with exogenous DNA and detected by 32P-postlabeling. Successful application of a serum-based approach coupled with the use of the generally applicable, ultrasensitive 32P-postlabeling assay could evade the need for obtaining DNA from tissues, currently the major impediment in human biomonitoring studies.

Identification and Characterization of a Novel Benzo[a]pyrene-Derived DNA Adduct

“…Moreover, these adducts have also been found in rodent liver and lung following BP exposure (9,11). The predominant adduct has been previously identified to result from the reaction of anti-BPDE with the N 2 position of dG.…”

TOXICOKINETICS OF INHALED BENZO[a]PYRENE: Plasma and Lung Bioavailability

“…Benzo[a]pyrene diol epoxide has also been detected in lung homogenate of ferrets exposed to environmental tobacco smoke (Sindhu et al, 1996). Published evidence suggests that this metabolite forms complexes with serum albumin and lipoprotein, which enhance its stabilization and transportation (Ginsberg & Atherholt, 1990) throughout the circulation and cause damage in tissues/organs that are deficient in PAH-metabolizing enzymes (Garg et al, 1993). Benzo[a]pyrene diol epoxide was known to induce mutations in the hypoxanthine phosphoribosyl transferase gene (Lambert et al, 1994) and c-Ha-ras-1 proto-oncogene (Ramos et al, 1998).…”

The Gulf Oil Spill

“…PAHs form DNA adducts that can be measured in body tissues or blood in both humans and laboratory animals following exposure to PAHs or mixtures containing PAHs (e.g., Assennato et al 1993;Bjelogrlic et al 1994;Culp and Beland 1994;Day et al 1990;Fuchs et al 1993aFuchs et al , 1993bGarg et al 1993;Garner et al 1988;Gallagher et al 1993;Herberg et al 1990;Hughes and Phillips 1990;Hughes et al 1993;Khanduja and Majid 1993;Likhachev et al 1993;Lu et al 1993;Mass et al 1993;Newman et al 1988Newman et al , 1990Nowak et al 1992;Oueslati et al 1992;Roggeband et al 1994;Ross et al 1990Ross et al , 1991Shamshuddin and Gan 1988;Van Schooten et al 1991Weston et al , 1993aWeyand et al 1993aWeyand et al , 1993b. PAHs also form adducts with other cellular macromolecules, such as hemoglobin, globin, and other large serum proteins (e.g., Bechtold et al 1991;Sherson et al 1990;).…”