Pharmacokinetics and pharmacodynamics of orally administered acetylenic tricyclic bis(cyanoenone), a highly potent Nrf2 activator with a reversible covalent mode of action

• Published in: Biochemical and biophysical research communications 2015-09, Vol.465 (3), p.402-407
• Main Authors: Kostov, Rumen V., Knatko, Elena V., McLaughlin, Lesley A., Henderson, Colin J., Zheng, Suqing, Huang, Jeffrey T.-J., Honda, Tadashi, Dinkova-Kostova, Albena T.
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Administration, Oral; Animals; BLOOD; CARCINOGENESIS; CHRONIC INTAKE; COVALENCE; CYSTEINE; Cysteine targeting; DIET; Dose-Response Relationship, Drug; DOSES; DRUGS; ENZYME ACTIVITY; ENZYMES; FEEDING; Female; GENES; HALF-LIFE; HEART; Keap1; LIVER; Metabolic Clearance Rate; MICE; Mice, Inbred C57BL; NAD; NF-E2-Related Factor 2 - agonists; NQO1; Nrf2; Organ Specificity; Phenanthrenes - administration & dosage; Phenanthrenes - pharmacokinetics; Phenanthrenes - toxicity; Reversible covalent drug; STABLE ISOTOPES; Survival Rate; Tissue Distribution; TOXICITY
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2015.08.016

The acetylenic tricyclic bis(cyanoenone) TBE-31 is a highly potent cysteine targeting compound with a reversible covalent mode of action; its best-characterized target being Kelch-like ECH-associated protein-1 (Keap1), the cellular sensor for oxidants and electrophiles. TBE-31 reacts with cysteines of Keap1, impairing its ability to target nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) for degradation. Consequently, Nrf2 accumulates and orchestrates cytoprotective gene expression. In this study we investigated the pharmacokinetic and pharmacodynamic properties of TBE-31 in C57BL/6 mice. After a single oral dose of 10 μmol/kg (∼200 nmol/animal), the concentration of TBE-31 in blood exhibited two peaks, at 22.3 nM and at 15.5 nM, 40 min and 4 h after dosing, respectively, as determined by a quantitative stable isotope dilution LC-MS/MS method. The AUC0–24h was 195.5 h/nmol/l, the terminal elimination half-life was 10.2 h, and the kel was 0.068 h−1. To assess the pharmacodynamics of Nrf2 activation by TBE-31, we determined the enzyme activity of its prototypic target, NAD(P)H:quinone oxidoreductase 1 (NQO1) and found it elevated by 2.4- and 1.5-fold in liver and heart, respectively. Continuous feeding for 18 days with diet delivering the same daily doses of TBE-31 under conditions of concurrent treatment with the immunosuppressive agent azathioprine had a similar effect on Nrf2 activation without any indications of toxicity. Together with previous reports showing the cytoprotective effects of TBE-31 in animal models of carcinogenesis, our results demonstrate the high potency, efficacy and suitability for chronic administration of cysteine targeting reversible covalent drugs. •TBE-31 is a cysteine targeting compound with a reversible covalent mode of action.•After a single oral dose, the blood concentration of TBE-31 exhibits two peaks.•Oral TBE-31 is a potent activator of Nrf2-dependent enzymes in multiple organs.•Chronic dietary administration of TBE-31 at doses that show efficacy is not toxic.