Accelerating Discovery of Kinase Inhibitors Using an ADP Assay

An ADP assay can be used to study the activity of enzymes that phosphorylate substrates leading to signaling events in the body. One of a variety of post-translational modifications, protein phosphorylation regulates a diverse group of cellular functions. In cancer, abnormal phosphorylation events often play a role in proliferation, survival, motility, metabolism, and angiogenesis.¹ PI3K is just one example of the many kinases that phosphorylate signaling molecules that trigger a series of downstream reactions regulating cell survival.¹ Since kinases are proteins that manage phosphorylation, it makes sense that therapies that inhibit these enzymes have the potential to reverse several ailments, including cancer and inflammatory disorders.

The human immune response is complicated, and researchers continue to discover pathways and proteins that add to the complexity. Inflammation is a critical process involved in immune response, allowing our bodies to fight and eliminate disease. The inflammatory response recruits several mediators to aid in the destruction of whatever pathogen caused the reaction in the first place. There are several autoimmune diseases and illnesses with an overactive immune response. Moreover, researchers have recently found an overexuberant host inflammatory response in some COVID-19 patients. ²

This inflammatory response has led to a plethora of clinical trials to investigate the potential for kinase inhibitors, especially Janus kinase inhibitors. An ADP assay can be used to screen compound libraries for JAK inhibitors with anti-inflammatory and anti-viral effects. Janus kinases phosphorylate downstream proteins inducing cytokine production.³ Since cytokines (proteins involved in cell signaling) are responsible for driving and regulating the immune response, an imbalance can contribute to excessive inflammation.

An ADP Assay for Kinase Inhibitor Discovery

Researchers have already discovered hundreds of kinase inhibitors to combat a plethora of illnesses, including cancer and inflammatory-related disease; however, there is much to learn and even more potential for drug discovery. The Transcreener® ADP² Kinase Assay can detect the activity of Kinases, ATPases, and virtually any enzyme that produces ADP.

The easy-to-use universal ADP assay limits the need for specific reagents for each target. Kinases transfer a phosphate from ATP to another molecule (or substrate), forming ADP as a product. The assay uses a specific antibody and fluorophore tracer. Displacement of the tracer by ADP changes fluorescent characteristics generating a measure of activity.

Regardless of the results of current clinical trials regarding kinase inhibitors’ potential to treat COVID-19, various kinase inhibitors on the market are currently treating disease and many more to discover.

References

1. Gross, S., Rahal, R., Stransky, N., Lengauer, C., & Hoeflich, K. P. (2015). Targeting cancer with kinase inhibitors. Journal of Clinical Investigation, 125(5), 1780–1789. https://doi.org/10.1172/JCI76094
2. Mehta, P., Ciurtin, C., Scully, M., Levi, M., & Chambers, R. C. (2020). JAK inhibitors in COVID-19: The need for vigilance regarding increased inherent thrombotic risk. European Respiratory Journal, 56(3), 10–12. https://doi.org/10.1183/13993003.01919-2020
3. Wikipedia contributors. (2021, January 14). Protein kinase inhibitor. In Wikipedia, The Free Encyclopedia. Retrieved 11:56, January 17, 2021, from https://en.wikipedia.org/w/index.php?title=Protein_kinase_inhibitor&oldid=1000236143