To prevent excessive activation of NRF2 in tumor cells that show increased expression of the DPP3 gene, this project plans to explore the possibility of enhancing the KEAP1–NRF2 interaction by controlling the so-called moonlighting activity of DPP III. Namely, the KEAP1–NRF2 signaling pathway is the main regulator of the cellular response to oxidative and electrophilic stress. While activation of NRF2 protects normal cells from various toxic agents and diseases, overactivation of NRF2 has also been shown to promote cancer progression and protect cancer cells from oxidative damage resulting with chemoresistance and radioresistance. DPP III is one of the proteins from the KEAP1 interactome that competes with NRF2 for binding to KEAP1. In this project, we plan to conduct preliminary research to identify a molecule that will inhibit DPP III activity in the KEAP1–NRF2 signaling pathway. This molecule will specifically bind to the part of DPP III responsible for interaction with KEAP1, thereby preventing the formation of the KEAP1–DPP III complex. At the same time, this interaction will indirectly strengthen the binding between KEAP1 and NRF2 proteins. Given that the loop from the upper domain of DPP III, which contains the ETGE motif, directly interacts with the KEAP1 protein, the project will explore two different approaches to immobilizing this loop: a) finding a small molecule from large libraries of commercially available compounds that will directly bind to the ETGE-loop and thus reduce the affinity of DPP III for KEAP1, and b) constructing a mutated form of the Kelch domain that will show stronger binding to the ETGE-loop of DPP III than the endogenous KEAP1 protein found in breast cancer cells. All these methods would enable more efficient binding of NRF2 to KEAP1, thus promoting its ubiquitination. The proposed research has a pronounced interdisciplinary character, specifically involving the application of various methods from molecular biology, biochemistry, biophysics, and molecular modeling.