Authors

SP Bennett¹; K Cameron¹; AC Martin¹; K Pollock¹; MC Pritchard¹; LM Tonkin¹; 
¹ Cancer Research Horizons, UK

Discussion

A key part of our Drug Discovery process involves a high-throughput screen (HTS) of a target against small molecule libraries to identify inhibitors, also known as actives.  

Once a screen is complete, a cascade of biochemical and biophysical assays is required to progress and build confidence in the actives. Biochemical assays are employed to eliminate false positives such as compounds that interfere with the output signal or are redox active, and those that may aggregate the target or bind non-specifically. Once hits are triaged in the initial HTS follow-up, biophysical techniques are employed to confirm target engagement. More specialised biochemical assays are then used to understand the MOI and biophysical techniques are employed alongside to develop our understanding of how the small molecule is inhibiting, further.

The most suitable biophysical techniques for a given target and project must be chosen carefully as each has its own advantages and limitations which dictate feasibility, whether its throughput, a high protein requirement, protein stability or tags. A variety of methods are used at CRH-TI, including NMR, SPR, and ITC. Each biophysical method should not be used in isolation as orthogonal techniques (including biochemical assays) are required to build confidence in our understanding.

This poster will review Biophysical methods and how we have used them to demonstrate target engagement and help define a small molecules mechanism of inhibition. Such examples include using SPR to interrogate how a small molecule competitively disrupts a protein-protein interaction, and the subsequent used of Protein observed NMR as the orthogonal method to further verify this result, building confidence in the exact MOI.

As we explore and understand a target-inhibitor interaction in greater detail, the most appropriate compounds will progress from Hit to Lead and ultimately help to develop the best cancer therapeutics.