Better Target Validation for Drug Discovery with CRISPR/Cas9

Better target validation is a key driver of better productivity in drug discovery. The RNA-guided nucleases, exemplified by Cas9, represent a powerful new approach to understanding gene function and, in principle, to reveal the next generation of therapeutic targets. But how well does this technology work in practice? 

Horizon Discovery has used CRISPR/Cas9 to perform pooled screens of a 3,000-gene library, that includes protein and lipid kinases against a panel of some 35 cell lines predominantly derived from colon and lung cancers. The primary screens were followed up with ultra-deep pooled validation screens using a high-performance tracrRNA providing insights into the potential role of pharmacologically modulatable domains in target function. This exercise has identified some exciting new potential synthetic lethal targets for cancer therapies and also an independent dataset implying that some of the prominent RNA-interference derived targets under evaluation in the field will have only narrow therapeutic windows.

The key question now is, can we de-risk this new portfolio of targets to move forward in drug discovery on the best opportunities with some confidence that optimized small molecule inhibitors will be useful for cancer therapy?

Horizon Discovery has been exploring the potential for various aspects of CRISPR/Cas9 technology to provide further validation. Key to this exercise is the development of conditional systems that can establish the biological significance of a target and move beyond mere statistical significance. Our featured speaker will describe the level of knockdown that can be achieved with degron-tagged CRISPR interference (CRISPRi) proteins, how best to deploy dox-inducible Cas9, and various approaches to delete wild-type alleles of genes so as to replace them with inactive alleles that could be applied at scale. Horizon believes that this suite of technology can improve the effectiveness and precision of target validation for its partners.  

Speaker

Paul Russell, PhD, Senior Scientist, Therapeutic R&D, Horizon Discovery

Paul joined Horizon in 2012 to work on and lead client target validation projects. For the last few years, Paul has developed and performed Horizon’s internal target identification and validation programs utilizing both CRISPR & RNAi based technologies. Prior to working at Horizon, Paul performed research at the University of Cambridge, where he studied the early BRCA genetics in Breast & Ovarian cancer with Prof Bruce Ponder. With Prof Ashok Venkitaraman, he subsequently studied the role of the spindle assembly checkpoint in determining the outcome from a drug induced mitotic arrest. During this time, he was an early adopter of full genome siRNA screening to address a number biological questions.

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