Développement de méthodes analytiques par LC-MS/MS pour la caractérisation de l’activité et de l’expression des CYP450s chez l’humain
This research project is divided into two sections, both aiming at the development of sensitive and specific LC-MS methods to evaluate activity and expression of CYP450 and finally, looking at their clinical application. The first section of this research project focuses on the development of analytical methods by LC-MS/MS for a seven CYP450 probe-drug cocktail. Although these cocktails have shown value they also suffer from many limitations. Our objective was to develop and validate highly sensitive and selective LC-MS/MS assays allowing the determination of CYP1A2, 2B6, 2C9, 2C19, 2D6, 3A4/5 and 2E1 activities following administration of low oral doses of a modified CYP450 probe-drug cocktail in patients. These methods can be used to phenotype CYP450 activities, evaluate inter-individual variabilities, study the impact of pathological conditions on drug metabolism and elimination, and evaluate drug-drug interactions. Our CYP450 cocktail assays have been successfully applied to phenotype CYP450 activities in type 2 diabetic patients. The second section of this project aims at the development of a LC-HRMS method for the characterization and absolute quantification of CYP1A1, 1A2, 1B1, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2, 3A4, 3A5, 3A7 and 4F2 in the human small intestine. Our hypothesis suggests that CYP450 isoenzymes found along the small intestine can significantly affect the first-pass effect of certain drugs administered orally and thus influence their pharmacological and/or toxic effects. My participation in this project allowed to identify proteotypic peptides by in silico and in vitro digestion and to develop LC-HRMS methods allowing the absolute quantification of CYP450. This project is a first step in the characterization of the main CYP450 along the small intestine. This project will allow a better understanding of inter-individual variability in drug response associated with intestinal absorption of drugs, a better prediction of variability in drug bioavailability and to develop more complex pharmacokinetic models.
LC-MS/MS CYP450 probe-drug cocktail Drug metabolism Proteomic Phenotyping