Primary Cells and Stem Cells in Drug Discovery: Emerging Tools for High-Throughput Screening

Abstract

Many drug discovery screening programs employ immortalized cells, recombinantly engineered to express a defined molecular target. Several technologies are now emerging that render it feasible to employ more physiologically, and clinically relevant, cell phenotypes. Consequently, numerous approaches use primary cells, which retain many functions seen in vivo, as well as endogenously expressing the target of interest. Furthermore, stem cells, of either embryonic or adult origin, as well as those derived from differentiated cells, are now finding a place in drug discovery. Collectively, these cells are expanding the utility of authentic human cells, either as screening tools or as therapeutics, as well as providing cells derived directly from patients. Nonetheless, the growing use of phenotypically relevant cells (including primary cells or stem cells) is not without technical difficulties, particularly when their envisioned use lies in high-throughput screening (HTS) protocols. In particular, the limited availability of homogeneous primary or stem cell populations for HTS mandates that novel technologies be developed to accelerate their adoption. These technologies include detection of responses with very few cells as well as protocols to generate cell lines in abundant, homogeneous populations. In parallel, the growing use of changes in cell phenotype as the assay readout is driving greater use of high-throughput imaging techniques in screening. Taken together, the greater availability of novel primary and stem cell phenotypes as well as new detection technologies is heralding a new era of cellular screening. This convergence offers unique opportunities to identify drug candidates for disorders at which few therapeutics are presently available.

Whole-cell biosensor for label-free detection of GPCR-mediated drug responses in personal cell lines

“…Examples linking GPCR polymorphisms to drug response to date are sparse and focus on statistic associations followed by validating polymorphism influences by generating these variants in heterologous cell lines (Ishiguro et al, 2010). Heterologous cell lines, however, are labor intensive to make and represent a different, non-physiological cellular context than cells of an individual (Eglen and Reisine, 2011;Yu et al, 2006). Receptor overexpression, differences in intracellular metabolic conditions as well as products from other genes could modify cellular responses.…”

“…While several examples have linked GPCR polymorphisms to disease and drug response variation, research has mostly focused on the statistics of genotype influences followed by functional characterization in heterologous cell lines (Docherty et al, 2012;Ishiguro et al, 2010;Sadee et al, 2001). Heterologous cell lines are, however, systems with artificial receptor expression and represent a non-physiological, cellular context (Eglen and Reisine, 2011;Yu et al, 2006). To fully understand the underlying mechanism of polymorphism influence, functional characterization on a physiologically relevant molecular and cellular level is vital.…”

Model Systems for Cardiovascular Regenerative Biology

“…Although primary cardiomyocyte isolation can be expensive and time-consuming, primary cells are considered to be more representative of cell behavior in vivo compared with cell lines (Eglen and Reisine 2011). Adult mammalian CMs have been considered to be postmitotic, having undergone an incomplete cycle of cell division during the neonatal period, resulting in CMs that are binucleated or multinucleated (Ausoni and Sartore 2009;Walsh et al 2010).…”

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

“…Over the past decade, cell-based screening technology in this area has rapidly developed in three major directions: (1) novel analytical technologies used to analyze cell responsiveness in highthroughput screening (HTS) or high-content screening (HCS) formats, (2) new approaches to generate and genetically manipulate the assay cells using, for example, CRISPR-Cas-9 (clustered, regularly interspaced, short palindromic repeats-CRISPR-associated protein) genome engineering, 1 and (3) increasing the relevance of the cell phenotype used in the assay to the in vivo situation. 2 Indeed, the use of tumorderived cells has evolved to include broader use of human primary cells-particularly those derived from stem cell progenitors. 2 Much of cell culture is undertaken in two dimensions (2D).…”