ABSTRACT
Pharmacological activation of NRF2 (nuclear factor erythroid 2-related factor 2) arises from blocking the interaction of NRF2 with its negative regulator, KEAP1 (Kelch-like ECH-associated protein 1). We previously reported an isoquinoline-based NRF2 activator, but this compound showed negative logD7.4 and a -2 charge at physiological pH, which may have limited its membrane permeability. In this work, we report potent, metabolically stable analogs that result from replacing a carboxymethyl group at the 4-position with a fluoroalkyl group.
Subject(s)
Drug Discovery , Isoquinolines/chemistry , Isoquinolines/pharmacology , Kelch-Like ECH-Associated Protein 1/antagonists & inhibitors , NF-E2-Related Factor 2/antagonists & inhibitors , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Drug Stability , Humans , Protein BindingABSTRACT
Activators of nuclear factor-erythroid 2-related factor 2 (NRF2) could lead to promising therapeutics for prevention and treatment of oxidative stress and inflammatory disorders. Ubiquitination and subsequent degradation of the transcription factor NRF2 is mediated by Kelch-like ECH-associated protein-1 (KEAP1). Inhibition of the KEAP1/NRF2 interaction with small molecules leads to NRF2 activation. Previously, we and others described naphthalene-based NRF2 activators, but the 1,4-diaminonaphthalene scaffold may not represent a drug-like scaffold. Paying particular attention to aqueous solubility, metabolic stability, potency, and mutagenicity, we modified a previously known, naphthalene-based nonelectrophilic NRF2 activator to give a series of non-naphthalene and heterocyclic scaffolds. We found that, compared to previously reported naphthalene-based compounds, a 1,4-isoquinoline scaffold provides a better mutagenic profile without sacrificing potency, stability, or solubility.
Subject(s)
Gene Expression Regulation/drug effects , Isoquinolines/pharmacology , Kelch-Like ECH-Associated Protein 1/metabolism , NF-E2-Related Factor 2/metabolism , Naphthalenes/chemistry , Protein Interaction Domains and Motifs/drug effects , Small Molecule Libraries/pharmacology , Cells, Cultured , Humans , Isoquinolines/chemistry , Kelch-Like ECH-Associated Protein 1/chemistry , Kelch-Like ECH-Associated Protein 1/genetics , Keratinocytes/cytology , Keratinocytes/drug effects , Keratinocytes/metabolism , Mutagenesis , NF-E2-Related Factor 2/chemistry , NF-E2-Related Factor 2/genetics , Salmonella typhimurium/drug effects , Salmonella typhimurium/geneticsABSTRACT
Activation of the transcription factor Nrf2 has been posited to be a promising therapeutic strategy in a number of inflammatory and oxidative stress diseases due to its regulation of detoxifying enzymes. In this work, we have developed a comprehensive structure-activity relationship around a known, naphthalene-based non-electrophilic activator of Nrf2, and we report highly potent non-electrophilic activators of Nrf2. Computational docking analysis of a subset of the compound series demonstrates the importance of water molecule displacement for affinity, and the X-ray structure of di-amide 12e supports the computational analysis. One of the best compounds, acid 16b, has an IC50 of 61 nM in a fluorescence anisotropy assay and a Kd of 120 nM in a surface plasmon resonance assay. Additionally, we demonstrate that the ethyl ester of 16b is an efficacious inducer of Nrf2 target genes, exhibiting ex vivo efficacy similar to the well-known electrophilic activator, sulforaphane.
