NUAK kinases: signaling mechanisms and therapeutic applications

The novel (nua) kinases 1 and 2 are two of 12 AMP-activated protein-related kinases whose signaling pathways are involved in cancer progression, as well as neurologic, fibrotic, and inflammatory diseases. Currently, there are 80 FDA-approved kinase inhibitors which target roughly 24 of the 500+ known human kinases, leaving most kinases underexplored, including NUAK1 and NUAK2. Thus, there is a critical need for selective inhibition of NUAK1 and NUAK2 signaling. Here we review the protein structure, known upstream regulators and downstream targets, and expression profiles of NUAK1 and NUAK2 in cancerous compared to non-cancerous tissue. We also delineate the biological roles and signaling pathways of the NUAK kinases in a range of malignancies, focusing on cancer but also covering non-cancerous physiology, and the therapeutic potential of NUAK kinase inhibition. We summarize the known small molecule NUAK kinase inhibitors in preclinical models and one inhibitor in clinical trials. This review highlights the signaling mechanisms and therapeutic value of targeting NUAK kinase signaling pathways with specific, small molecule NUAK inhibitors.