Design of a Potent, Selective, and Brain-Penetrant Inhibitor of Wnt-Deactivating Enzyme Notum by Optimization of a
Nicky J Willis1, William Mahy1, James Sipthorp1,2
1Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
Abstract:
Notum is a carboxylesterase that suppresses Wnt signaling through deacylation of an essential palmitoleate group on Wnt proteins. There is a growing understanding of the role Notum plays in human diseases such as colorectal cancer and Alzheimer's disease, supporting the need to discover improved inhibitors, especially for use in models of neurodegeneration. Here, we have described the discovery and profile of 8l (ARUK3001185) as a potent, selective, and brain-penetrant inhibitor of Notum activity suitable for oral dosing in rodent models of disease. Crystallographic fragment screening of the Diamond-SGC Poised Library for binding to Notum, supported by a biochemical enzyme assay to rank inhibition activity, identified 6a and 6b as a pair of outstanding hits. Fragment development of 6 delivered 8l that restored Wnt signaling in the presence of Notum in a cell-based reporter assay. Assessment in pharmacology screens showed 8l to be selective against serine hydrolases, kinases, and drug targets.
Insights
Researchers discovered a new brain-penetrant drug, 8l, that inhibits Notum, an enzyme involved in Wnt signaling. This discovery offers a potential new treatment for neurodegenerative diseases like Alzheimer's and colorectal cancer.
Area of Science:
- Biochemistry
- Neuroscience
- Medicinal Chemistry
Background:
- Notum carboxylesterase suppresses Wnt signaling by removing a palmitoleate group from Wnt proteins.
- Notum's role in diseases like colorectal cancer and Alzheimer's disease necessitates the development of novel inhibitors.
- Targeting Notum is crucial for therapeutic interventions in neurodegeneration and cancer.
Purpose of the Study:
- To discover and profile a potent, selective, and brain-penetrant inhibitor of Notum activity.
- To develop a compound suitable for oral administration in rodent models of disease.
- To identify novel therapeutic agents for Wnt signaling pathway modulation.
Main Methods:
- Crystallographic fragment screening of the Diamond-SGC Poised Library against Notum.
- Biochemical enzyme assays to determine inhibition activity and selectivity.
- Cell-based reporter assays to assess Wnt signaling restoration.
Main Results:
- Identified 6a and 6b as potent hits through fragment screening and enzyme assays.
- Developed 8l (ARUK3001185) from fragment leads, demonstrating potent and selective Notum inhibition.
- 8l restored Wnt signaling in cell-based assays and showed selectivity against other enzymes.
Conclusions:
- 8l is a highly potent, selective, and brain-penetrant Notum inhibitor.
- 8l is suitable for oral dosing in preclinical models of disease.
- This discovery provides a promising therapeutic candidate for diseases involving aberrant Wnt signaling.
