Red and processed meat intake is associated with increased risks of both colorectal adenoma and cancer. Processed meats contain nitrate and nitrite, precursors of N-nitroso compounds (NOCs); furthermore, meats cooked at high temperatures contain heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Specific NOC, HCA and PAH are mutagens and animal carcinogens. We conducted a c...

Cytochrome P450 2A13 (CYP2A13), an enzyme expressed predominantly in the human respiratory tract, exhibits high efficiency in the metabolic activation of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). A C-->T transition in the CYP2A13 gene causes Arg257Cys amino acid substitution and, thus, results in a significantly reduced activity toward NNK and other substrates. In...

BACKGROUND The ratio of 3'hydroxycotinine to cotinine, or nicotine metabolite ratio (NMR), is strongly associated with CYP2A6 genotype, CYP2A6-mediated nicotine and cotinine metabolism, and nicotine clearance. Higher NMR (faster nicotine clearance) is associated retrospectively with heavier smoking and lower cessation rates. METHODS NMR as a predictive biomarker of cessation outcomes is being...

The inhibition and mechanism-based inactivation potencies of irinotecan (7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin; CPT-11) and its active metabolite (7-ethyl-10-hydroxycamptothecin; SN-38) for human cytochrome P450 (P450) enzymes were investigated to evaluate the potential for drug interactions involving CPT-11 using microsomes from insect cells expressing specific huma...

Heterologous expression using baculovirus vectors has become a popular method for the production of catalytically active cytochrome P450s (CYPs). We have systematically optimized the multiplicity of infection (MOI) for a coinfection approach for the coexpression of CYP2A6 (viral vector designated v2A6) and NADPH-P450 oxidoreductase (OR; viral vector designated vOR) using Sf9 insect cells. A 300...

Background Cigarette smoking is a major risk factor for chronic obstructive pulmonary disease (COPD) and COPD severity. Previous genome-wide association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) associated with the number of cigarettes smoked per day (CPD) and a dopamine beta-hydroxylase (DBH) locus associated with smoking cessation in multiple populations. ...

Determining drug-metabolizing enzyme activities on an individual basis is an important component of personalized medicine, and cytochrome P450 enzymes (CYPs) play a principal role in hepatic drug metabolism. Herein, a simple method for predicting the major CYP-mediated drug clearance in vitro and in vivo is presented. Ten CYP-mediated drug metabolic activities in human liver microsomes (HLMs) f...

Cancer is a leading cause of death worldwide. The cancer incidence rate in Chile is 133.7/100,000 inhabitants and it is the second cause of death, after cardiovascular diseases. Most of the antineoplastic drugs are metabolized to be detoxified, and some of them to be activated. Genetic polymorphisms of drug-metabolizing enzymes can induce deep changes in enzyme activity, leading to individual v...