The Keap1-Nrf2-ARE Pathway As a Potential Preventive and Therapeutic Target: An Update.

The Keap1-Nrf2-ARE ((Kelch-like ECH-Associating protein 1) nuclear factor erythroid 2 related factor 2-antioxidant response element) pathway is one of the most important defense mechanisms against oxidative and/or electrophilic stresses, and it is closely associated with inflammatory diseases, including cancer, neurodegenerative diseases, cardiovascular diseases, and aging. In recent years, progress has been made in strategies aimed at modulating the Keap1-Nrf2-ARE pathway. The Nrf2 activator DMF (Dimethylfumarates) has been approved by the FDA as a new first-line oral drug to treat patients with relapsing forms of multiple sclerosis, while a phase 3 study of another promising candidate, CDDO-Me, was terminated for safety reasons. Directly inhibiting Keap1-Nrf2 protein-protein interactions as a novel Nrf2-modulating strategy has many advantages over using electrophilic Nrf2 activators. The development of Keap1-Nrf2 protein-protein interaction inhibitors has become a topic of intense research, and potent inhibitors of this target have been identified. In addition, inhibiting Nrf2 activity has attracted an increasing amount of attention because it may provide an alternative cancer therapy. This review summarizes the molecular mechanisms and biological functions of the Keap1-Nrf2-ARE system. The main focus of this review is on recent progress in studies of agents that target the Keap1-Nrf2-ARE pathway and the therapeutic applications of such agents.

Discovery of a NCOA4 Degrader for Labile Iron-Dependent Ferroptosis Inhibition.

Ferroptosis, a distinctive form of programmed cell death, has been implicated in numerous pathological conditions, and its inhibition is considered a promising therapeutic strategy. Currently, there is a scarcity of efficient antagonists for directly regulating intracellular ferrous iron. Ferritinophagy, an essential process for supplying intracellular labile iron, relies on nuclear receptor coactivator 4 (NCOA4), a selective autophagy receptor for the ferritin iron storage complex, thus playing a pivotal role in ferritinophagy. In this study, we reported a novel von Hippel-Lindau-based NCOA4 degrader, V3, as a potent ferroptosis inhibitor with an intracellular ferrous iron inhibition mechanism. V3 significantly reduced NCOA4 levels and downregulated intracellular ferrous iron (Fe2+) levels, thereby effectively suppressing ferroptosis induced by multiple pathways within cells and alleviating liver damage. This research presents a chemical knockdown tool targeting NCOA4 for further exploration into intracellular ferrous iron in ferroptosis, offering a promising therapeutic avenue for ferroptosis-related acute liver injury.

An inhibitor of the Keap1-Nrf2 protein-protein interaction protects NCM460 colonic cells and alleviates experimental colitis.

Ulcerative colitis (UC) is a chronic relapsing-remitting form of inflammatory bowel disease (IBD) that increases the risk of colorectal cancer, the third most common malignancy in humans. Oxidative stress is a risk factor for the development of UC. The Keap1-Nrf2-ARE pathway is one of the most important defensive mechanisms against oxidative and/or electrophilic stresses. In this study, we identified CPUY192018 as a potent small-molecule inhibitor of the Keap1-Nrf2 PPI, investigated the cyto-protective effects of CPUY192018 on the NCM460 colonic cells and evaluated whether treatment with the inhibitor of the Keap1-Nrf2 PPI exerts protection on an established experimental model of UC induced by dextran sodium sulfate (DSS). Our study clearly demonstrated that CPUY192018 had a cytoprotective effect against DSS in both NCM460 cells and mouse colon via the activation of Nrf2 signaling. These results suggested that activation of Nrf2 by directly inhibiting the Keap1-Nrf2 PPI may be beneficial as a treatment for UC.

Polar Recognition Group Study of Keap1-Nrf2 Protein-Protein Interaction Inhibitors.

Directly disrupting the Keap1-Nrf2 protein-protein interaction (PPI) has emerged as an attractive way to activate Nrf2, and Keap1-Nrf2 PPI inhibitors have been proposed as potential agents to relieve inflammatory and oxidative stress diseases. In this work, we investigated the diacetic moiety around the potent Keap1-Nrf2 PPI inhibitor DDO1018 (2), which was reported by our group previously. Exploration of bioisosteric replacements afforded the ditetrazole analog 7, which maintains the potent PPI inhibition activity (IC50 = 15.8 nM) in an in vitro fluorescence polarization assay. Physicochemical property determination demonstrated that ditetrazole replacement can improve the drug-like property, including elevation of pK a, log D, and transcellular permeability. Additionally, 7 is more efficacious than 2 on inducing the expression of Nrf2-dependent gene products in cells. This study provides an alternative way to replace the diacetic moiety and occupy the polar subpockets in Keap1, which can benefit the subsequent development of Keap1-Nrf2 PPI inhibitor.