Related Experiment Video
Updated: May 19, 2026
A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds
Published on: April 6, 2016
A template model for studying anticancer drug efflux transporter inhibitors in vitro
Alexandre Sostelly1, Léa Payen, Jérôme Guitton
1EMR3738, Ciblage Thérapeutique en Oncologie, Faculté de Médecine et de Maïeutique Lyon-Sud Charles Mérieux, Oullins, France. alexandre.sostelly@gmail.com
Abstract:
Efflux transporters play an important role in drug absorption and also in multidrug resistance. ABCG2 (BCRP) is an efflux transporter conferring cross-resistance to mitoxantrone (Mit), irinotecan (CPT11), and its active metabolite SN38. MBLI87, a new ABCG2 inhibitor has proven its efficacy against ABCG2-mediated efflux in vitro and in vivo. This work aimed at modeling and quantifying the cellular interaction between MBLI87 and different substrates using a mechanistic template model. An in vitro competition experiment study was carried out with HEK293 cells overexpressing ABCG2 exposed to fixed concentrations of substrates (Mit, CPT11, SN38) and to MBLI87 at several concentration levels. A nonlinear mixed-effects transport inhibition model was developed to fit intracellular drug concentrations. In this model, drugs cross the cell membrane through passive diffusion, active drug efflux is ABCG2 mediated, interaction between substrates and inhibitor occurs within the transporter. The interaction was found to be noncompetitive. The MBLI87 Ki was estimated to 141 nm for Mit, 289 nm for CPT11, and 1160 nm for SN38. The ratio of intrinsic transport clearance divided by diffusion clearance was estimated to 2.5 for Mit, 1.01 for CPT11, and 5.4 for SN38. The maximal increase in the intracellular substrate concentration that is possible to achieve by inhibition of the transporter was estimated to 1.5 for Mit, 0.1 for CPT11, and 4.4 for SN38. This mechanistic template model describes both drug accumulation and cellular transport, and the mixed-effects approach allows an estimation of intra- and interassay variability. This model is of great interest to study cytotoxic cellular pharmacokinetics.
Insights
A new ABCG2 inhibitor, MBLI87, was studied for its interaction with substrates like mitoxantrone and irinotecan. The mechanistic model revealed noncompetitive inhibition, aiding the understanding of drug accumulation and transport in cells.
Area of Science:
- Pharmacology
- Biochemistry
- Cell Biology
Background:
- Efflux transporters, such as ABCG2 (BCRP), are crucial in drug absorption and multidrug resistance.
- ABCG2 mediates resistance to several chemotherapy drugs, including mitoxantrone, irinotecan, and SN38.
- MBLI87 is a novel inhibitor demonstrating efficacy against ABCG2-mediated efflux.
Purpose of the Study:
- To model and quantify the cellular interaction between the ABCG2 inhibitor MBLI87 and its substrates.
- To elucidate the mechanism of inhibition and characterize the kinetic parameters of MBLI87-substrate interactions.
- To develop a mechanistic template model for studying drug accumulation and transport influenced by ABCG2.
Main Methods:
- In vitro competition experiments using HEK293 cells overexpressing ABCG2.
- Exposure of cells to fixed substrate concentrations (mitoxantrone, irinotecan, SN38) and varying MBLI87 concentrations.
- Development and application of a nonlinear mixed-effects transport inhibition model to fit intracellular drug concentrations.
Main Results:
- The interaction between MBLI87 and substrates was characterized as noncompetitive inhibition.
- Estimated inhibition constants (Ki) for MBLI87 were 141 nm (mitoxantrone), 289 nm (irinotecan), and 1160 nm (SN38).
- The model quantified ratios of intrinsic transport clearance to diffusion clearance and predicted maximal intracellular substrate concentration increases.
Conclusions:
- The developed mechanistic template model accurately describes drug accumulation and cellular transport kinetics.
- The mixed-effects approach provides robust estimation of intra- and interassay variability.
- This model is valuable for studying the pharmacokinetics of cytotoxic drugs and understanding ABCG2-mediated transport inhibition.
