Abstract

For many
years cell-based assays have widely been used in drug discovery. Traditionally,
cells are plated in a 2D monolayer and are used to test the potency and
efficacy of drug candidates. However, it is becoming increasingly clear that
this model of cell culture is not truly representative of how cells grow and
respond in vivo. Growing cells in a 3D format produces a
microenvironment allowing for more complex cell to cell and extracellular
matrix interactions therefore allowing a better representation of in
vivo cell physiology which is lost in the traditional monolayer format.

We have  implemented
3D cell culture techniques which can easily be adapted into an HTS format.
Ultra-low attachment (ULA) plates allow spheroids to naturally form, this
technology relies upon a cells innate ability to grow and interact in a 3D
format to form a spheroid. Spheroids tend to develop gradients of oxygen,
nutrients and metabolites therefore creating a mixed population of cells with a
hypoxic core and replicating cells on the outer edge. Using this technology, we
were able to monitor drug potency and efficacy in either an imaging-based assay
on the CellInsight^TM CX5 High Content Screening (HCS) Platform
(Thermo Scientific^TM) or by using commercially available assays such
as the CellTiter Glo ® 3D viability assay from Promega. Here we test two spheroid
cultures derived from either a HCT116 (human colorectal carcinoma) or U87
(human glioblastoma) cell line. We have used a number of parameters to generate
a pharmacological profile of each spheroid type.