Identification of novel ferroptosis and necroptosis inhibitors - Optimising the therapeutic potential by improving pharmacokinetic properties

Promovendus/a: Camilla Scarpellini

Promotor(en): Prof. Koen Augustyns, Prof. Hans De Winter

Cell death can be a consequence of different stress conditions that cells undergo, and it is considered an essential process to control the biological homeostasis of tissues and multicellular organisms. In the past 20 years many novel types of regulated cell death (RCD) have been identified. Particularly, ferroptosis and necroptosis emerged as new types of non-apoptotic forms of cell death involved in different human pathologies such as neurodegenerative diseases, ischemia-reperfusion injury, ocular surface dysfunctions and cardiac diseases. Thus, ferroptosis and necroptosis inhibitors may have therapeutic potential.
This project focused on the design, synthesis, and biological evaluation of novel ferroptosis and necroptosis inhibitors. The goal was to address the phospholipid peroxide accumulation with radical trapping antioxidants (RTAs) for ferroptosis, and to target the activity of receptor-interacting serine/threonine-protein kinase 1 (RIPK1) kinase to suppress necroptosis.
We initiated the ferroptosis segment of the project by utilising UAMC-3203, a novel RTA that was developed within our group. This compound exhibited high potency, stability, solubility and safety in different animal models. To further improve its pharmacokinetics properties, the drug-likeness and permeability, we modified UAMC-3203 introducing different moieties leading to different series of analogues. The majority of the compounds showed high potency in the in vitro assay with an IC50 < 100 nM and in the FENIX assay, a spectrophotometric method to determine lipophilic RTAs potency confirming their anti-ferroptotic potential. UAMC-3844 was the best compound of the series with improved potency and microsomal stability.
In addition, the section on necroptosis started from GSK2656157 (GSK’157), a supposedly specific inhibitor of protein kinase R (PKR)-like ER kinase (PERK), which we previously identified as a much more potent RIPK1 inhibitor. We performed further structural optimisation on the GSK’157 scaffold to develop a novel class of more selective RIPK1 inhibitors. Introducing different substituents on the para-position of the pyridinyl ring we synthesised a series of novel GSK’157 analogues with increased selectivity for RIPK1. The most selective compounds were screened by western blot and tested in vitro for their ability to inhibit RIPK1-dependent apoptosis and necroptosis. The optimisation led to UAMC-3861 as the best compound of this series in terms of activity and selectivity for RIPK1 over PERK. The docking study confirmed our hypothesis therefore leading to a novel series of potent and selective type II RIPK1 inhibitors based on the GSK’157 scaffold.
The most promising candidates, UAMC-3844 and UAMC-3861 can be considered to study ferroptosis and necroptosis driven diseases in vivo.