In Depth Analysis of Kinase Cross Screening Data to Identify CAMKK2 Inhibitory Scaffolds

Area of Science:

• Biochemistry and Molecular Biology
• Pharmacology
• Drug Discovery

Background:

• Calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) is a key kinase involved in numerous physiological processes.
• CAMKK2 deregulation is implicated in oncological, metabolic, and inflammatory diseases, highlighting its therapeutic potential.
• Existing inhibitors, like STO-609, are often assumed to be selective but may lack specificity.

Purpose of the Study:

• To evaluate the selectivity of STO-609, a commonly cited CAMKK2 inhibitor.
• To identify and validate novel, potent, and selective CAMKK2 inhibitors.
• To provide tools for further research into CAMKK2's role in disease.

Main Methods:

• Literature and public database analysis to identify potential CAMKK2 inhibitors.
• Differential scanning fluorimetry (DSF) assays to assess inhibitor activity.
• Enzyme inhibition assays to confirm and quantify inhibitory potency and selectivity.

Main Results:

• STO-609 demonstrated potent inhibition against multiple kinases, not just CAMKK2, challenging its purported selectivity.
• Several novel potent CAMKK2 inhibitors were identified through literature and database searches.
• Validated activities of identified inhibitors using DSF and enzyme inhibition assays.

Conclusions:

• STO-609 is a promiscuous kinase inhibitor, necessitating caution in its use for CAMKK2-specific studies.
• The identified and validated inhibitors represent promising starting points for developing selective CAMKK2 therapeutics.
• These selective inhibitors will be valuable tools for dissecting CAMKK2's function in various disease contexts.