Drug Discovery Goes Three-Dimensional: Goodbye to Flat High-Throughput Screening?

Immortalized cells, generated from two-dimensional cell culture techniques, are widely used in compound screening, lead optimization, and drug candidate selection. However, such cells lack many characteristics of cells in vivo. This could account for the high failure rates of lead candidates in clinical evaluation. New approaches from cell biology, materials science, and bioengineering are increasing the utility of three-dimensional (3D) culture. These approaches have become more compatible with automation and, thus, provide more physiologically relevant cells for high-throughput/high-content screening, notably in oncology drug discovery. Techniques range from simple 3D spheroids, comprising one or more cell types, to complex multitissue organoids cultured in extracellular matrix gels or microfabricated chips. Furthermore, each approach can be applied to stem cells, such as induced pluripotent stem cells, thereby providing additional phenotypic relevance and the exciting potential to enable screening in disease-specific cell types.