Abstract B140: Elucidating the novel mechanism of action of VVD-065, an allosteric molecular glue for the KEAP1-CUL3 E3-ligase complex that promotes NRF2 degradation in NRF2-activated cancers

Abstract

Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that plays a crucial role in various NRF2-dependent cancers. The protein levels of NRF2 are tightly controlled by a specific E3 ligase complex composed of Kelch-like ECH Associated Protein 1 (KEAP1), Cullin 3 (CUL3), and RING-box protein 1 (RBX1). Under normal conditions, KEAP1 acts as an oxidative sensor and facilitates the ubiquitination and subsequent degradation of NRF2. However, during oxidative or electrophilic stress, KEAP1 can be inactivated through covalent modification of sensor cysteine residues, allowing NRF2 levels to increase and regulate NRF2-dependent genes. In this study, we have elucidated a novel mechanism-of-action for a first-in-class NRF2 inhibitor, VVD-065. Through biochemical and biophysical investigations, we have discovered that VVD-065 functions by covalently interacting with KEAP1 at a sensor cysteine residue, but surprisingly this interaction results in an enhanced affinity between KEAP1 and CUL3, and an increased capacity for Keap1 mediated NRF2 degradation. High-resolution co-crystal structures have revealed that binding of VVD-065 allosterically induces a conformational change that mimics the conformation of KEAP1 when in complex with CUL3. By targeting the KEAP1-CUL3 interaction and promoting the degradation of NRF2, VVD-065 offers a means to modulate NRF2 levels in NRF2-dependent cancers. The unprecedented mechanism of action exhibited by VVD-065 has been confirmed through in vitro and in vivo studies, paving the way for the development of a clinically relevant Keap1 activator.

Citation Format: Aaron Snead, Steffen Bernard, Kenneth Hee, Eileen Tran, Sarah Jacinto, Nil Roy, Tine Wyseure, Jonathan Pollock, Gabe Simon, Todd Kinsella, David Weinstein, Matt Patricelli. Elucidating the novel mechanism of action of VVD-065, an allosteric molecular glue for the KEAP1-CUL3 E3-ligase complex that promotes NRF2 degradation in NRF2-activated cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B140.