Many synthetic and naturally occurring phenols and catechols, such as butylated hydroxytoluene, butylated hydroxyanisole, alpha- tocopherol and plant flavonoids produces a variety of effects, including carcinogenesis, anti-carcinogenesis, tumor promotion and cytotoxicity. The elucidation of mechanisms by which these compounds exert their effects will lead to a better understanding of the biochemical events involved, and furnish valuable clues for the development of agents useful in cancer prevention and treatment. The biological effects elicited by phenolic compounds have been shown in several cases to be due to biotransformation processes, but little is known about the details of these relationships. Phenoxy radicals formed during enzymatic (or nonenzymatic) one- electron oxidations of phenols may form highly reactive peroxyquinols by combining with molecular oxygen. In general, these pathways have not been intensively studied because they do not represent quantitatively major metabolic processes, and because the resulting quinonoid species are usually too reactive to be observed. Recent studies with synthetic peroxyquinols confirmed the role of these species as metabolic intermediates in liver microsomes and isolated hepatocytes. Furthermore, they were shown to adversely affect biochemical parameters while exerting a considerably higher level of toxicity than their phenolic precursors.
The specific aims for the project are as follows. (1) Investigate mechanistic details of hemoprotein-peroxyquinol interactions. Preliminary work with cytochrome P-450 will be extended to other important hemoproteins. Detailed studies of the products generated and their pathways of formation will be conducted. The effects of peroxyquinol structure on the nature and the amounts of intermediates and products formed will provide data to test proposed mechanisms. (2) Determine the mechanistic basis for the effects of peroxyquinols on cellular biochemistry. Peroxyquinols of varying structures will be added to isolated hepatocytes and their effects on cell viability, thiols, NADPH, lipid peroxidation, and the generation of reactive oxygen species will be determined, as well as covalent binding to cellular protein. Attempts will be made to correlate the biochemical data with specific peroxidative pathways. (3) Investigate metabolic products and biochemical effects of alkylated phenols. The metabolism and biochemical effects of phenolic precursors of the peroxyquinols will be investigated in hepatocytes and subcellular fractions. This data will provide further information concerning the importance of peroxyquinol pathways to the biological effects of alkylated phenols.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Metabolic Pathology Study Section (MEP)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Colorado at Boulder
Schools of Pharmacy
United States
Zip Code
Shearn, Colin T; Fritz, Kristofer S; Thompson, John A (2011) Protein damage from electrophiles and oxidants in lungs of mice chronically exposed to the tumor promoter butylated hydroxytoluene. Chem Biol Interact 192:278-86
Shearn, Colin T; Fritz, Kristofer S; Meier, Brent W et al. (2008) Carbonyl reductase inactivation may contribute to mouse lung tumor promotion by electrophilic metabolites of butylated hydroxytoluene: protein alkylation in vivo and in vitro. Chem Res Toxicol 21:1631-41
Meier, Brent W; Gomez, Jose D; Kirichenko, Oleg V et al. (2007) Mechanistic basis for inflammation and tumor promotion in lungs of 2,6-di-tert-butyl-4-methylphenol-treated mice: electrophilic metabolites alkylate and inactivate antioxidant enzymes. Chem Res Toxicol 20:199-207
Meier, Brent W; Gomez, Jose D; Zhou, Angela et al. (2005) Immunochemical and proteomic analysis of covalent adducts formed by quinone methide tumor promoters in mouse lung epithelial cell lines. Chem Res Toxicol 18:1575-85
Lemercier, Jean-Noel; Meier, Brent W; Gomez, Jose D et al. (2004) Inhibition of glutathione S-transferase P1-1 in mouse lung epithelial cells by the tumor promoter 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone (BHT-quinone methide): protein adducts investigated by electrospray mass spectrometry. Chem Res Toxicol 17:1675-83
Sun, Yude; Dwyer-Nield, Lori D; Malkinson, Alvin M et al. (2003) Responses of tumorigenic and non-tumorigenic mouse lung epithelial cell lines to electrophilic metabolites of the tumor promoter butylated hydroxytoluene. Chem Biol Interact 145:41-51
Kupfer, Rene; Dwyer-Nield, Lori D; Malkinson, Alvin M et al. (2002) Lung toxicity and tumor promotion by hydroxylated derivatives of 2,6-di-tert-butyl-4-methylphenol (BHT) and 2-tert-butyl-4-methyl-6-iso-propylphenol: correlation with quinone methide reactivity. Chem Res Toxicol 15:1106-12
Kupfer, R; Liu, S Y; Allentoff, A J et al. (2001) Comparisons of hydroperoxide isomerase and monooxygenase activities of cytochrome P450 for conversions of allylic hydroperoxides and alcohols to epoxyalcohols and diols: probing substrate reorientation in the active site. Biochemistry 40:11490-501
Thompson, J A; Carlson, T J; Sun, Y et al. (2001) Studies using structural analogs and inbred strain differences to support a role for quinone methide metabolites of butylated hydroxytoluene (BHT) in mouse lung tumor promotion. Toxicology 160:197-205
Dwyer-Nield, L D; Thompson, J A; Peljak, G et al. (1998) Selective induction of apoptosis in mouse and human lung epithelial cell lines by the tert-butyl hydroxylated metabolite of butylated hydroxytoluene: a proposed role in tumor promotion. Toxicology 130:115-27

Showing the most recent 10 out of 19 publications