Biological and Medicinal Chemistry

Design of a potent, selective and brain penetrant inhibitor of Wnt-deactivating enzyme Notum by optimization of a crystallographic fragment hit



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 disease such as colorectal cancer and Alzheimer’s disease supporting the need to discover improved inhibitors, especially for use in models of neurodegeneration. Here, we describe the discovery and profile of 8l (ARUK3001185) as a potent, selective and brain pentrant 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, identifed 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.


Thumbnail image of 2022.03.15 - Manuscript. ChemRXiv.pdf

Supplementary material

Thumbnail image of 2022.03.15 - Supporting Information. ChemRXiv.pdf
Additional Experimental Data, Figures and Tables
Overlay of DSPL screening hits 6. ADME protocols and data. Pharmacokinetic studies. Notum OPTS and TCF/LEF screening data concentration-response curves. Activity-based protein profiling optimization. Serine hydrolase selectivity of 1. Kinase selectivity panel. Safety pharmacology studies. DSC for azide 12a. X-ray structure determination: data collection and refinement statistics; ligand electron-density maps. Spectroscopic and analytical data for 8l (PDF)
Thumbnail image of ABPP Supplementary Data Set.xlsx
Activity-based protein profiling
Identity and quantification of each serine hydrolase identified in SW620 cells by FP-biotin ABPP (XLSX)