LAUSR

Although oral dosing is the most convenient route of drug administration, most anti-neoplastic drugs are administered intravenously due to poor bioavailability because of the epithelial barriers. A major organ involved in oral drug absorption is the small intestine where enterocytes are linked together by tight junctions (TJs). TJs regulate paracellular transport by creating a selectively permeable barrier to small molecules, ions, and water, thereby restricting the uptake of drugs. Transient modulation of the TJs is considered a potential strategy to improve drug delivery. Human small intestinal (SI) organoids are 3D in vitro models of the epithelium which recapitulate the structure and function of the small intestine. However, their geometry prevents access to the apical compartment of the epithelium (the outer, or luminal, surface being located within the organoid with the basal surface on the outside), making them unsuitable for the study of orally-administered drugs. Here we describe a method to generate transwell-grown cell monolayers derived from normal human small intestine, that allows direct access to the apical surface. We demonstrate that the format provides an in vivo-like cell composition, comprising of all the intestinal cellular types, including stem cells, Paneth cells, goblet cells, enteroendocrine cells and enterocytes, and respond to treatment with ‘tool drug’ TJ modulators such as sodium caprate, chitosan, EGTA and various cytokines. Briefly, for the generation of transwell-grown cell monolayers, SI organoids were dissociated into single cells and plated in matrix-coated transwell inserts. The monolayer formation was followed by live imaging and Trans-Epithelial Electrical Resistance (TEER) measurements. Treatments with TJ modulators were applied after TEER reached a plateau (8-10 days after plating), and effects on TJs were evaluated 24-72 hours after treatment by TEER reduction, FITC-Dextran permeability increase and analysis of TJ proteins by immunofluorescence. In conclusion, our models provide an innovative in vitro solution to study the effect of TJ modulators on increasing paracellular transport of orally-administered, anti-neoplastic drugs. Furthermore, as anti-neoplastic drugs can also have toxic effects on the intestinal epithelium by affecting TJs, thereby creating a leaky barrier, the model is useful to predict such effects and stratify drug candidates prior to in vivo studies. The model also provides a system to test the restorative potential of molecules on barrier integrity that could be used in combination or after the administration of anti-neoplastic drugs. Citation Format: Valentina Ubertini, Frida Ponthan, Aude-Marine Bonavita, James Wilson. Transwell-grown monolayers derived from small intestinal organoids to study the effects of tight junction modulators that may improve the absorption of orally-administered, anti-neoplastic drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2754.