Synthesis and evaluation of tricyclic pyrrolopyrimidinones as dipeptide mimetics: inhibition of interleukin-1beta-converting enzyme

Interleukin-1β converting enzyme (ICE): A comprehensive review on discovery and development of caspase-1 inhibitors

Caspase-1 is a critical mediator of the inflammatory process by activating various pro-inflammatory cytokines such as pro-IL-1β, IL-18 and IL-33. Uncontrolled activation of caspase-1 leads to various cytokines-mediated diseases. Thus, inhibition of Caspase-1 is considered therapeutically beneficial to halt the progression of such diseases. Currently, rilonacept, canakinumab and anakinra are in use for caspase-1-mediated autoinflammatory diseases. However, the poor pharmacokinetic profile of these peptides limits their use as therapeutic agents. Therefore, several peptidomimetic inhibitors have been developed, but only a few compounds (VX-740, VX-765) have advanced to clinical trials; because of their toxic profile. Several small molecule inhibitors have also been progressing based on the three-dimensional structure of caspase-1. However there is no successful candidate available clinically. In this perspective, we highlight the mechanism of caspase-1 activation, its therapeutic potential as a disease target and potential therapeutic strategies targeting caspase-1 with their limitations.

Synthesis and evaluation of novel 8,5-fused bicyclic peptidomimetic compounds as interleukin-1β converting enzyme (ICE) inhibitors

An 8,5-fused bicyclic peptidomimetic ring system generated by a stereoselective ring metathesis reaction was elaborated into potent inhibitors of interleukin-1beta converting enzyme (ICE, caspase-1). Multiple compounds were found that exhibited ICE IC50 values < 10 nM and were selective over caspase-3 and caspase-8. These active analogs generally possessed good activity (IC50 values < 100 nM) in a whole cell assay measuring IL-1beta production. Pharmacokinetic analysis of the ethyl acetal prodrug form of a selected active lead revealed a compound with a reasonable plasma half-life (1.1 h) and good oral bioavailability (30%).

Synthesis and evaluation of thiazepines as interleukin-1beta converting enzyme (ICE) inhibitors

A series of monocyclic thiazepine inhibitors of interleukin-1beta converting enzyme (ICE) were synthesized in eight steps from commercially available intermediates. In vitro biological evaluation showed the thiazepines to be moderately potent ICE inhibitors, with the most active compound exhibiting an IC50 value of 30 nM in an enzyme inhibition assay. Compounds of this class possessed good selectivity against the related enzymes caspase-3 and caspase-8.