An Insectified Caco-2 Cell-Based assay to monitor pesticide Transport Processes and Pharmacokinetics

Abstract

Intestinal insect cells are integral to pharmacokinetic research, unfortunately they do not serve as cell models for more advanced studies comparable to transport studies typically conducted in mammalian models. To overcome this limitation, in this study, we developed a Caco-2 cell line that has been genetically modified to mimic insect-like characteristics, providing a robust insectified screening platform to monitor transport processes of xenobiotics. This platform consists of Wild Type (Pgpwild type) cells, an Pgp Knockout (PgpKO) line to eliminate endogenous background interference, and species-specific P-gp rescue lines. These rescue lines allow for the stable expression of human (Hs Pgp), cotton bollworm (Ha Pgp), and malaria mosquito (Ag Pgp) homologs, enabling a direct comparative analysis of efflux kinetics across different pesticide target and non-target biological systems. Functional validation using the substrate Digoxin confirmed high P-gp dependency within the platform. Methyl-parathion, an organophospate insecticide, was recognised and transported by both insect and human Pgps. This is consistent with the low mammalian selectivity of the compound. In contrast, Triflumezopyrim exhibited a high efflux ratio that remained remarkably stable even in the absence of MDR1, indicating that the uptake and pharmacokinetics of this compound are not Pgp-dependent. By successfully differentiating between transporter-specific and independent pathways these cell lines can serve as a high-fidelity screening tool for predicting novel pesticide selectivity and possibly validating the potential role of transporters in resistance. The system can be expanded and exploit also other transporters.