Identification of Allosteric Inhibitors against Active Caspase-6.
Tubeleviciute-Aydin, A., Beautrait, A., Lynham, J., Sharma, G., Gorelik, A., Deny, L.J., Soya, N., Lukacs, G.L., Nagar, B., Marinier, A., LeBlanc, A.C.(2019) Sci Rep 9: 5504-5504
- PubMed: 30940883 
- DOI: https://doi.org/10.1038/s41598-019-41930-7
- Primary Citation of Related Structures:  
6DEU, 6DEV - PubMed Abstract: 
Caspase-6 is a cysteine protease that plays essential roles in programmed cell death, axonal degeneration, and development. The excess neuronal activity of Caspase-6 is associated with Alzheimer disease neuropathology and age-dependent cognitive impairment. Caspase-6 inhibition is a promising strategy to stop early stage neurodegenerative events, yet finding potent and selective Caspase-6 inhibitors has been a challenging task due to the overlapping structural and functional similarities between caspase family members. Here, we investigated how four rare non-synonymous missense single-nucleotide polymorphisms (SNPs), resulting in amino acid substitutions outside human Caspase-6 active site, affect enzyme structure and catalytic efficiency. Three investigated SNPs were found to align with a putative allosteric pocket with low sequence conservation among human caspases. Virtual screening of 57,700 compounds against the putative Caspase-6 allosteric pocket, followed by in vitro testing of the best virtual hits in recombinant human Caspase-6 activity assays identified novel allosteric Caspase-6 inhibitors with IC 50 and K i values ranging from ~2 to 13 µM. This report may pave the way towards the development and optimisation of novel small molecule allosteric Caspase-6 inhibitors and illustrates that functional characterisation of rare natural variants holds promise for the identification of allosteric sites on other therapeutic targets in drug discovery.
Organizational Affiliation: 
Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Ch. Cote Ste-Catherine, Montreal, Quebec, H3T 1E2, Canada.