IEC-18 Cells

The IEC-18 cell line is a non-transformed epithelial cell line derived from the crypt cells of rat small intestine. These cells have been shown to effectively model the physiological properties of the small intestinal epithelium, particularly with respect to chloride ion (Cl⁻) transport. Chloride channels in IEC-18 cells exhibit distinct types of conductances that respond to various stimuli such as cell swelling, increased intracellular calcium (Ca²⁺), and elevated cyclic AMP (cAMP). For instance, swelling-activated Cl⁻ currents in IEC-18 cells are characterized by outward rectification and voltage independence. Moreover, IEC-18 cells express cystic fibrosis transmembrane conductance regulator (CFTR) channels, evidenced by the presence of cAMP-activated Cl⁻ conductance which can be inhibited by glibenclamide and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), but not affected by DIDS.

IEC-18 cells have also been used to explore cell survival mechanisms under detachment-induced stress, known as anoikis. Research indicates that prostaglandin E2 (PGE2) can promote cell viability and aggregation in detached IEC-18 cells through cAMP-mediated signaling pathways. This protection from anoikis is associated with the activation of adenylate cyclase and protein kinase A (PKA), enhancing cell adhesion and viability even in suspended states. Such findings are significant for understanding inflammation-related processes and potential contributions to carcinogenesis in intestinal tissues.

Furthermore, IEC-18 monolayers have been employed to study the transport of various molecules across the intestinal barrier. Compared to the Caco-2 cell line, IEC-18 cells provide a more accurate model for passive transcellular and paracellular transport due to their structural similarities to small intestine crypt cells. Unlike Caco-2 cells, which possess significant active transport capabilities, IEC-18 cells demonstrate minimal carrier-mediated transport, making them a more suitable choice for analyzing the passive permeability of hydrophilic macromolecules.