Biotransformation in the liver is accomplished by two classes of enzymes; namely phase I and phase II biotransformation enzymes. Cytochome P450s (CYPs) are pivotal phase I mono-oxygenase enzymes involved in the synthesis and degradation of endogenous steroid hormones, vitamins, and fatty acid derivatives, but also in the transformation of xenobiotics such as drugs and environmental chemicals into more hydrophilic molecules, thus facilitating their excretion (1). Of this CYP family, CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A4 are considered to be the major isoforms responsible for the metabolism of the majority of marketed drugs in humans. Inhibition or induction of CYPs by drugs can cause drug-drug interactions, altering their effectiveness or resulting in toxic interactions (2). In addition, CYP isozyme levels can be affected by other factors such as age and disease (3).
The purpose of this proposed CYP induction in vitro test method is to evaluate the potential of a test chemical (see Table 1) to induce CYP mediated via PXR/CAR (CYP3A4, CYP2B6) and the Ah-135 receptor (CYP1A2) in rat and human based cells, thus establishing differences. The selection of these three CYP isoforms, which are recommended by the EMA and FDA Guidelines, is based on the fact that in humans they are involved in the biotransformation of a wide variety of endogenous and exogenous chemicals and that they are target CYPs for classical model inducers: CYP1A2 for dioxins and PAHs, CYP2B6 for phenobarbital and CYP3A4 for rifampicin.
Before my masters degree in biological sciences in UK, I have worked as a full time job as a chemistry and science teacher in a school, and I was also used to demonstrate in the lab during my M.Phil (back home). During my masters degree at Royal Holloway, University of London, I have brushed up my skills and gained some knowledge about proteins/peptides and drugs used for the detection and treatment of breast cancer.
Currently, I am doing PhD at Kingston University, London in analytical chemistry.