Discovery of 4-Anilinoquinolinylchalcone Derivatives as Potential NRF2 Activators.

Yu-Tse Kao,Jin-Ching Lee,Yi-Siao Chen,Kai-Wei Tang,Chia-Hung Yen,Cherng-Chyi Tzeng,Yeh-Long Chen,Chih-Hua Tseng

doi:10.3390/molecules25143133

Abstract

Activation of nuclear factor erythroid-2-related factor 2 (NRF2) has been proven to be an effective means to prevent the development of cancer, and natural curcumin stands out as a potent NRF2 activator and cancer chemopreventive agent. In this study, we have synthesized a series of 4-anilinoquinolinylchalcone derivatives, and used a NRF2 promoter-driven firefly luciferase reporter stable cell line, the HaCaT/ARE cells, to screen a panel of these compounds. Among them, (E)-3-{4-[(4-acetylphenyl)amino]quinolin-2-yl}-1-(4-fluorophenyl)prop-2-en-1-one (13b) significantly increased NRF2 activity in the HaCaT cell with a half maximal effective concentration (EC50) value of 1.95 μM. Treatment of compound 13b upregulated HaCaT cell NRF2 expression at the protein level. Moreover, the mRNA level of NRF2 target genes, heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glucose-6-phosphate dehydrogenase (G6PD) were significantly increased in HaCaT cells upon the compound 13b treatment. The molecular docking results exhibited that the small molecule 13b is well accommodated by the bound region of Kelch-like ECH-associated protein 1 (Keap1)-Kelch and NRF2 through stable hydrogen bonds and hydrophobic interaction, which contributed to the enhancement of affinity and stability between the ligand and receptor. Compound 13b has been identified as the lead compound for further structural optimization.

Highlights

The nuclear factor erythroid-2-related factor (NRF2) is a transcription factor that is sensitive to oxidative stress
Luciferase activities were determined after cells treated with test compounds at a concentration of 10 μM for 24 h. tert-Butyl hydroquinone (t-BHQ), a well-known nuclear factor erythroid-2-related factor 2 (NRF2) activator in antioxidant response element (ARE)-controlled gene transcription, showed 1880% induction of ARE-driven luciferase activity, was used as the positive control
Our results indicated the best substituent for R2 is the acetyl group in all the 4-anilinoquinolinylchalcone derivatives tested and (E)-3-{4-[(4-acetylphenyl)amino]quinolin-2-yl}-1-(4-fluorophenyl)prop-2-en- 1-one (13b, R1 = F, R2 = COMe) was the most potent NRF2 activator, which enhanced ARE promoter activity to 2205%

Summary

Introduction

The nuclear factor erythroid-2-related factor (NRF2) is a transcription factor that is sensitive to oxidative stress. NRF2 activity is suppressed by Kelch-like ECH-associated protein 1 (Keap1), which is a substrate adaptor for Cullin-3 (CUL3) [1,2,3]. NRF2 will be ubiquitinated by CLU3 and be degraded by proteasome. Molecules 2020, 25, 3133 oxygen species (ROS) or electrophiles oxidize key sensor cysteine residues in Keap and change its conformation, which disrupts the interaction between Keap and NRF2 [4]. NRF2 can enter the nucleus and forms dimer with sMaf. NRF2 can enter the nucleus and forms dimer with sMaf This dimer binds to the antioxidant response element (ARE)

Methods

Results

Conclusion