Applications of Three-Dimensional Cell Cultures in the Early Stages of Drug Discovery, Focusing on Gene Expressions, Drug Metabolism, and Susceptibility.

Three-dimensional (3D) cell cultures represent advances in the way in which cells are grown in vitro, and they are gaining ground for a variety of applications. Advantages of 3D systems include reliable and realistic study endpoints. Cells grown in 3D conditions mimic in vivo conditions to an extent that is not possible with traditional 2D cell-culture methods. One major area in which 3D cell cultures have proven to make a difference is with drug discovery. The facets taken advantage of for drug discovery are the cells' complex microenvironment, including the production of extracellular matrices, altered gene expressions and their protein products, drug metabolism, and susceptibility to drugs when compared to 2D cultures. Altered protein and gene expressions are useful for drug-target identification. The susceptibility of 3D cultured cells for drug-induced effects can be used to obtain realistic data in a dose-dependent manner that can aid in identifying effective drug dosage. This review presents the contributions of 3D cell cultures for drug discovery, taking into consideration gene and protein expressions, drug metabolism, and susceptibility to drugs as the major focus points.