As the pharma and biotech industries search out new chemical entities, advances in drug screening technology have been sought as a way to control spiraling R&D costs. Newly perfected label-free technologies for drug screening are at the forefront, providing novel ways of interrogating cellular and molecular binding events. Academics and researchers from the industry discussed the current state of the art at “Assay and Screening Technologies” held recently in San Francisco.
“Invitrogen’s goal is to provide a rapid way to examine drug effects with functional cell-based assays that monitor specific ligand-receptor interactions,” said Richard Somberg, Ph.D., the company’s Wisconsin regional business manager. He discussed several products from Invitrogen, a division of Life Technologies, including a new cell-based assay known as LanthaScreen.
LanthaScreen is a time-resolved fluorescence resonance energy transfer (FRET) assay. It uses the rare earth cryptate element Terbium, which serves as donor, transferring energy to a fluorescent molecule when the two molecules are brought into close proximity.
In one of the LanthaScreen’s typical assays, a cell line is engineered with a green fluorescent protein gene fused to one of several kinase targets. The cells are subjected to a treatment that will stimulate phosphorylation, the cells are lysed, and a Terbium-labelled antibody specific to the phosphorylated molecule is added. This triggers the FRET reaction, and a powerful signal is produced. The beauty of this technology is that it has the properties of a single-step ELISA with high specificity and sensitivity, according to Dr. Somberg.
“We promote two different technologies—LanthaScreen for direct target modification measurements (e.g., phosphorylation, ubiquitination, acetylation) and CellSensors for total pathway activity measurements. Together, there are over 250 fully validated cell-based assays available off-the-shelf.”