Mechanistic insight from in silico pharmacokinetic experiments: roles of P-glycoprotein, Cyp3A4 enzymes, and microenvironments.
نویسندگان
چکیده
Saquinavir exhibits paradoxical transport across modified Caco-2 cell monolayers (doi: 10.1124/jpet.103.056390) expressing P-glycoprotein and Cyp3A4. The data implicate complicated intracellular transport mechanisms. Drawing on recent discrete event modeling and simulation advances, we built an in silico analog of the confluent, asymmetric cell monolayer used in the cited work. We call it in silico experimental Caco-2 (cell monolayer) culture (ISECC). Concrete, working, hypothesized spatial mechanisms were implemented. Validation was achieved when in silico experimental results met similarity measure (SM) expectations that targeted 16 wet-lab experimental conditions. Initial mechanistic hypotheses turned out to be necessary parts of a more complicated explanation. We progressed through four stages of an iterative refinement and validation protocol that enabled and facilitated discovery of plausible, new mechanistic details. The process exercised abductive reasoning, a primary means of scientific knowledge creation and creative cognition. The ISECC that survived the most stringent SM challenge produced transport data that was statistically indistinguishable from referent wet-lab observations. It required a 7:1 ratio of apical transporters to metabolizing enzymes, a 97% reduction of efflux activity by an inhibitor, a biased distribution of metabolizing enzymes, heterogeneous intracellular spaces, and restrictions on intracellular drug movement. Experimenting on synthetic analogs such as ISECC provides a former unavailable means of discovering new mechanistic details and testing their plausibility. The approach thus provides a powerful new expansion of the scientific method: an independent, scientific means to challenge, explore, better understand, and improve any inductive mechanism and, importantly, the assumptions on which it rests.
منابع مشابه
Effect of Honey on CYP3A4 Enzyme and P-Glycoprotein Activity in Healthy Human Volunteers
The activity of cytochrome p450 isozyme 3A4 (CYP3A4) enzyme and P-glycoprotein (P-gp) is modulated by grapefruit juice and herbal drugs. CYP3A4 is the major phase I drug metabolizing enzyme and P-gp is an ATP-dependent drug efflux pump that regulates the intestinal absorption of orally administered drugs. Honey is commonly consumed as a dietary supplement. However, its influence on human CY...
متن کاملDrug-Drug Interactions: Influence of verapamil on the pharmacokinetics of sitagliptin in rats and Ex vivo models
P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4) play a significant role in the disposition and elimination of drugs. The objective of this study was to investigate the mechanism underlying the interaction between sitagliptin (substrate of P-gp and CYP3A4) and verapamil (known modulator of P-gp and CYP3A4) using in vivo, ex vivo and in situ models. Rats were treated with sitagliptin (10 m...
متن کاملDmd048017 50..59
Recent data suggest that the role of CYP3A4 in imatinib metabolism is smaller than presumed. This study aimed to evaluate the quantitative importance of different cytochrome P450 (P450) enzymes in imatinib pharmacokinetics. First, the metabolism of imatinib was investigated using recombinant P450 enzymes and human liver microsomes with P450 isoform-selective inhibitors. Thereafter, an in silico...
متن کاملEffects of Salinispora derived metabolites against multidrug resistance, an in-silico study
Background: Multidrug resistance (MDR) is known to defeat most chemotherapies as one of the main anticancer strategies. The role of overexpression/overactivation of ABC transporters, especially P-glycoprotein (P-gp), in the development of chemotherapy has long been demonstrated. Salinispora is a marine actinomycete genus known for the production of novel bioactive metabolites. Methods: In this...
متن کاملAutoinhibition of CYP3A4 leads to important role of CYP2C8 in imatinib metabolism: variability in CYP2C8 activity may alter plasma concentrations and response.
Recent data suggest that the role of CYP3A4 in imatinib metabolism is smaller than presumed. This study aimed to evaluate the quantitative importance of different cytochrome P450 (P450) enzymes in imatinib pharmacokinetics. First, the metabolism of imatinib was investigated using recombinant P450 enzymes and human liver microsomes with P450 isoform-selective inhibitors. Thereafter, an in silico...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of pharmacology and experimental therapeutics
دوره 332 2 شماره
صفحات -
تاریخ انتشار 2010