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Flow Cytometry in Early Drug Discovery

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Flow cytometry is an exceptionally useful methodology used in all stages of drug development, and current instruments that run flow cytometry offer flexibility, sensitivity, reproducibility, and high-throughput assessments to deliver accurate data. A flow cytometer works by processing an injected sample that contains fluorescently labeled cells, analyzing each cell one at a time, to gather large amounts of high-quality data to sort and characterize and identify cells. 

In early drug discovery, flow cytometry can be used to analyze cell populations and detect rare cell types rapidly. In later stages of the drug development process, it can be used to monitor the efficacy and safety of drugs in clinical trials, often also used for identifying biomarkers for diagnosis and prognosis. The value of the data gathered is tremendous and can be used across every phase of the drug development program, helping pharmaceutical companies develop sharper drug development strategies. In this article, we focus on the applications using flow cytometry in the early stages of drug discovery.

Target-based screening is one such application where potential receptor-ligand interactions that may affect binding interactions between targeted molecules, can be identified. Target multiplexing allows high throughput screening and offers cell-by-cell analysis. Primary cells and tissues may be screened providing insights into dose-based responses, toxicity profiling, and more. Recent advances in instrumentation have allowed researchers to study critical cell populations with minimal sample waste. In addition to protein-protein interactions, flow cytometry advances also shed light on metabolic activity and cell viability. By using viability stains and cell proliferation assays, live and dead cell populations can be separated for cleaner data. Phenotypic screening involves screening compounds for the ability to deliver a particular phenotype that is associated with a therapeutic effect and is typically used for small molecules. 

Biologics screening is another area where this platform has showcased efficiencies. As one of the fastest-growing therapeutic modalities, biologics covers many therapeutic approaches with varying functionalities. To develop such antibody-based therapeutics, flow cytometry methods are used to quickly select and characterize candidates with better target reactivity and functionality. In an application used at GlaxoSmithKline, the objective of the study was to assess multiple hybridoma supernatants for antibodies binding to 1) cells expressing a human protein of interest, 2) negative control cells expressing a related but different protein, and 3) cells expressing the orthologous protein from two different animal species of interest. To accomplish this, the four different cell populations were barcoded by incubation with four different concentrations of a fluorescent dye, then incubated in wells together with hybridoma supernatants and reporter antibodies that had their own distinct fluorescence signature. Multiplexing techniques help researchers screen large pools of candidates to pick out lead candidates that exhibit cross-reactivity against multiple species early in the discovery process. 

In early drug discovery, flow cytometry is a technique used to isolate cells containing specific targets, characterize small molecules, identify biomarkers, analyze immune responses, and more. No matter the stage your molecule is in, Frontage’s scientists can build custom assays to deliver the results you need to advance your product. Contact us for your custom assay development projects.