Drug cytotoxicity screening using human intestinal organoids propagated with extensive cost-reduction strategies

Background:Physiologically relevant cell models, including organoids, are considered to be reliable tools for recapitulating human biology. Although organoids are useful for cell-based compound screening, which may facilitate drug development, their applications are limited. Intestinal organoids are composed of multiple types of intestinal epithelial cells found in vivoand replicate organ structures and complexities. A major limitation of using organoids in screening studies is the high cost of their culture when commercially available recombinant proteins are used. Methods: We previously succeeded in reducing the cost of human intestinal organoid culture by using the conditioned medium (CM) of L cells that stably co-express Wnt3a, R-spondin1, and Noggin via lentiviral infection. Based on this, we worked on further cost reduction by replacing expensive materials with cheaper ones and expanded the organoids in a more cost-effective way for a large-scale assay. Results: We replaced recombinant hepatocyte growth factor protein with CM for human intestinal organoid culture.Moreover, collagen gel was used instead of Matrigel for organoid culture, and organoid proliferation rate, as well as marker gene expression, was largely unchanged. The combination of these replacements significantly contributed to cost reduction for culturing organoids and organoid-oriented monolayer cells. Furthermore, compound screening of thousands of known bioactive substances was performed using human intestinal organoids cultured with the refined cost-reduction strategies, and several compounds with more selective cytotoxicity against organoid-derived cells than Caco-2 cells were identified. The mechanism of action of one of these compounds, YC-1, was further elucidated. We showed that YC-1 induces apoptosis through the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Conclusions:These results indicate that our methodologies for cost reduction enable large-scale organoid culture and subsequent compound screening, which may further expand the application of intestinal organoids and organoids in general in various research fields, including both theoretical and applied science.