Larson B, Banks P, Cameron G, Pierre N
BioTek Instruments, Inc., Winooski, VT, USA. TAP Biosystems, Royston, Hertfordshire, UK. CisBio US, Inc., Bedford, MA, USA.
Over the last decade, a central focus forimproving drug efficacy in clinical trials has been to increase the biological relevance of assays performed early in the drug discovery process. Yet it remains difficult to simulate a drug’s in vivo response using an in vitro assay. In vitro assays typically use cells grown on two-dimensional (2D) hard plastic or glass substrates, which are not representative of the true in vivo cell environment1. In tissue, cells interact with neighboring cells and with the extracellular matrix (ECM) to form a communication network that affects many cellular processes including proliferation, migration and apoptosis2. In a simplified, in vitro 2D environment, most of the tissue-specific architecture, cell-cell communication and cues are lost. Therefore the need exists for advanced culture methods that better mimic cellular function within living tissue. Three-dimensional (3D) cell culture methods, in comparison, provide a matrix that encourages cells to organize into structures more indicative of the in vivo environment, thereby developing normal cell-cell and cell-ECM interactions in an in vitro environment. Here, we demonstrate an in vitro HTRF® microplate assay from Cisbio Bioassays (Bedford, MA, USA) that asseses total and phosphorylated eukaryotic translation initiation factor 4E (eIF4E) using a novel 3D cell culture system. The RAFT™ (Real Architecture For 3D Tissue) cell culture system from TAP Biosystems (Royston, Hertfordshire, UK) creates a 3D hydrogel environment using the most abundant matrix protein, collagen type I, at physiologically relevant concentrations. Within this culture certain cells can assemble into higher order structures, termed tumoroids, driving cell-cell and cell-matrix interactions. The HTRF assay was also performed with cells cultured using traditional 2D methods for comparison.