Human iPS Cell-Derived Patient Tissues and 3D Cell Culture Part 1: Target Identification and Lead Optimization.

Human-induced pluripotent stem cells (HiPSCs), and new technologies to culture them into functional cell types and tissues, are now aiding drug discovery. Patient-derived HiPSCs can provide disease models that are more clinically relevant and so more predictive than the currently available animal-derived or tumor cell-derived cells. These cells, consequently, exhibit disease phenotypes close to the human pathology, particularly when cultured under conditions that allow them to recapitulate the tissue architecture in three-dimensional (3D) systems. A key feature of HiPSCs is that they can be cultured under conditions that favor formation of multicellular spheroids or organoids. By culturing and differentiating in systems mimicking the human tissue in vivo, the HiPSC microenvironment further reflects patient in vivo physiology, pathophysiology, and ultimately pharmacological responsiveness. We assess the rationale for using HiPSCs in several phases of preclinical drug discovery, specifically in disease modeling, target identification, and lead optimization. We also discuss the growing use of HiPSCs in compound lead optimization, particularly in profiling compounds for their potential metabolic liability and off-target toxicities. Collectively, we contend that both approaches, HiPSCs and 3D cell culture, when used in concert, have exciting potential for the development of novel medicines.