Chemical compound library
The chemical compound library to be used in this application is co-owned by CCIA and the Walter & Eliza Hall Medical Research Institute (WEHI) in Melbourne. It is a unique collection of 160,000 small molecule compounds selected for “lead-like” chemical structures and is based around the concept that smaller and polar compounds act as precursors for the development of successful drugs. These compounds have been individually screened and selected to have physio-chemical properties and occupy a wide range of chemical space suitable for hit identification and lead compound development.

High throughput screening
High throughput screening (HTS) of large chemical libraries of compounds is a proven way to identify novel chemical entities that target a biological system of interest. Using its state-of-the art high throughput cellular screening facility, the Drug Discovery Centre makes this technology available to biomedical researchers in NSW and beyond – facilitating drug discovery and development by defining the complex genetics/targets underlying cancer, isolating chemical compounds that affect specific cellular activities, and developing potential therapeutics or biological tools to target cancer-associated pathways.

Screening process
The cell-based assay will be adapted and optimised for HTS using positive and negative controls within the sponsor’s laboratory, utilising internal budgets and staff. Once the assay has been suitably optimised for HTS, the assay will be transferred from the sponsor’s laboratory into the Drug Discovery Centre, where further validation will be performed.

Initially, a pilot screen of 5,000 to 10,000 compounds will be performed to ensure the assay is robust and reproducible. Following this pilot screen, a larger primary screen will be performed using up to 50,000 compounds. It is estimated that the Drug Discovery Centre can screen up to 20,000 compounds per day.

Those small molecules identified as “hits” in the primary screen will be re-tested in triplicate at a single concentration to eliminate false positives. The hits displaying reproducible inhibitory activity will be tested in a full dose response titration using the original primary assay conditions. This will typically involve establishing dose response curves for 100 to 200 compounds. There is also the option to further test the hit compounds showing a dose response in secondary assays (specific to project).

Preliminary structure-activity relationship analysis will be performed by identifying focussed chemical compound libraries of up to 500 small molecules, based around the chemical structures of the hit compounds and their associated analogues. These focused libraries can then be screened as above using the primary screen conditions.

Screening equipment
The screening assay will be performed in the Drug Discovery Centre, which is equipped with cutting-edge liquid handling equipment (Hamilton MicroLab STAR and Nimbus automation systems), plate readers (Molecular Devices SpectraMax), plate washers (Biotek ELx405), liquid dispensers (Thermo Multidrop 384 and Multidrop Combi), and an extensive data management system (ActivityBase™).