Introduction: The Caco-2 permeability assay is widely used for lead optimization in drug discovery. A 3 to 5-day system using a 24-well plate and a 10 to 21-day system using a 96-well plate have been established. Here, we modified the assay system to provide a ready-to-use Caco-2 cell monolayer using a 96-well plate in just 4 days.
Methods and results: In our system, collagen-coated inserts and the prolongation of the culture period after seeding leads to greater Caco-2 cell proliferation and sufficient contact-inhibition. The differentiation of Caco-2 cells was enhanced, when the contact-inhibited Caco-2 cells were exposed to the differentiation-inducing agent butyric acid. The permeability to nine well-known compounds showed a statistical correlation between our 4-day system using a 96-well plate and the conventional 21-day system using a 24-well plate.
Discussion: We conclude that our system is more useful for evaluating many compounds for lead optimization in drug discovery.