Generic Fluorescent HTS Assay for Kinases and ATPases

DESCRIPTION (provided by applicant): There are over 500 protein kinases in the human genome and several hundred other enzymes that utilize ATP as a phosphate donor or energy source. Protein kinases are the second most intensively screened target class, with links to all of the major therapeutic areas, most notably cancer. Important disease links for cancer and anti-infectives also are emerging for lipid kinases, carbohydrate kinases and ATPases. Despite their high pharmaceutical relevance, the rapid movement of new ATP- dependent enzyme targets into drug discovery is being hampered by a lack of flexible high throughput screening (HTS) assay methods. This problem extends into secondary screening efforts for selectivity profiling and lead optimization as well. To address this need, BellBrook Labs has developed a novel fluorescence-based immunodetection method for ADP, the invariant product of all kinase and ATPase reactions. In Phase I, we developed a monoclonal antibody and fluorescent tracer that enable detection of ADP with 100-fold selectivity over ATP using fluorescence polarization as a readout. We commercialized the ADP detection platform as the Transcreener Kinase Assay kit in November, 2005, and it has since generated revenue approaching $250,000. In Phase II we propose to 1) enhance Transcreener Kinase Assay performance by developing a more selective ADP antibody, 2) extend the platform to additional target families, including GPCRs, by developing a similar immunodetection method for GDP, 3) increase HTS market penetration by formatting the assay for a second commonly used fluorescent detection mode, TR-FRET, 4) develop bioreactor hybridoma culture methods to scale up monoclonal antibody production and reduce animal usage, 5) use the unique capabilities of the Transcreener Kinase Assay to test a) the importance of using physiological protein substrates rather than widely used peptide acceptors for kinase screening and b) the potential for off target effects of kinase inhibitors with other types of ATP-dependent enzymes. By providing pharma with the tools and strategies to implement more physiological kinase screening methods, we hope to accelerate the discovery of improved therapies for cancer and other debilitating diseases. There are over 500 distinct protein kinase proteins encoded in the human genome and they have attracted intense interest from pharmaceutical companies because of their links with numerous types of cancer, inflammatory disorders such as arthritis, and other debilitating diseases. To accelerate the discovery of improved therapies for these diseases, we are developing an enabling screening method for finding drug molecules that will correct the aberrant behavior of malfunctioning kinase proteins.