Screening Strategies in Drug Discovery – Multimedia

High throughput (HT) and Ultra High Throughput (UHT) screening remains a valuable and necessary approach to modern drug discovery. Successful application of HTS requires accurate and meaningful handling of the experimental results. This means capturing vast data volumes generated by HTS and UHTS programmes and subsequent validation and verification. Decision making regarding HTS data can be supported via comprehensive and intuitive visualization of results.

High throughput screening (HTS) is an expensive part of the drug development process. Increasing the efficiency and productivity of HTS is a key objective for today’s discovery organizations. Predictive technology can be used to direct the screening of compounds prior to synthesis. However, issues such as the small proportion (usually less than 1%) of hits that occur in a given assay, complicate the application of statistical analysis and predictive modeling to this data.

Three pharmacophore searching methods were applied to finding potential ATP-competitive inhibitors of the Tyrosine Kinase family: i) manual pharmacophore modeling (MOE), ii) “fuzzy” pharmacophore models (SQUID), and iii) similarity searching based on correlation-vector representations of potential pharmacophore-points (CATS3D).

Traditional methods for High Content Analysis (HCA) use technologies such as flow cytometry and microscope-based imaging systems. Laser-scanning microplate cytometry has many advantages over these, and is more amenable for use in High Content Screening (HCS).

The activation of GPCRs is known to lead to the dynamic translocation of multiple signaling molecules or molecular assemblies during its signaling cycle, and in many cases cytoskelatal reorganization. Such a movement and/or reorganization results in dynamic redistribution of cellular contents, equivalent to dynamic mass redistribution (DMR), which can be monitored online in living cells using Corning® Epic™ system – a label-free and non-invasive biosensor system.

Enzyme Fragment Complementation can provide data for analysis of protein translocation events in whole cells, with the added benefits of increased throughput, simplified luminescence detection, no antibody requirements and decreased assay costs.

In this study, we have used an Acumen Explorer equipped with a violet 405nm laser in conjunction with a selection of shorter-wavelength amine-reactive fluorophores (Invitrogen, Molecular Probes) to demonstrate a greater utility for blue fluorescent probes within high content assays.

The DiscoveRx ADP Hunter™ assay measures the generation of ADP resulting from kinase phosphorylation of a substrate, in a format specifically designed for the high throughput screening laboratory. ADP is measured through a coupled enzyme system, which is linked to a positive, red-shifted fluorescent readout. The assay has a wide dynamic range (1.2 – 120 µM), and can be used with a wide range of ATP, from less than 5 µM up to 300 µM.

Here we present a web-based bioinformatics solution for the management and analysis of all areas of cell-based screen experimentation: the Laboratory Information Management System of the Technology Development Studio (TDS-LIMS). TDS-LIMS is a software package consisting of the Library Checker, Library Browser, Scheduling Kit, Screen Browser and Screen Publisher.

Here, laser scanning microplate cytometry has been used to provide an automated high content readout of the effects of cytostatic agents on colony formation. This approach determines colony number through the application of a spherical volume algorithm. This permits the differentiation of cytostatic effects where the number of colonies and size remains constant and cytotoxic effects where the size and number may be reduced.