Discovery of the first chemical tools to regulate MKK3-mediated MYC activation in cancer

• Type of Material: Article
• Authors: Xuan Yang, Emory University; Dacheng Fan, Emory University; Aidan H Troha, Emory University; Hyunjun Max Ahn, Emory University; Kun Qian, Emory University; Bo Liang, Emory University; Yuhong Du, Emory University; Haian Fu, Emory University; Andrey Ivanov, Emory University
• Language: English
• Date: 2021-07-29
• Publisher: PERGAMON-ELSEVIER SCIENCE LTD
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2021 The Authors. Published by Elsevier Ltd.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.bmc.2021.116324
• Title of Journal or Parent Work: BIOORGANIC & MEDICINAL CHEMISTRY
• Volume: 45
• Start Page: 116324
• End Page: 116324
• Grant/Funding Information: This research was supported in part by the National Cancer Institute of the NIH (Cancer Target Discovery and Development Network grants U01CA168449 and U01CA217875, H.F.), NCI Emory Lung Cancer SPORE (NIH P50CA217691) Career Enhancement Program awardee (A.A.I.), Emory initiative, Biological Discovery through Chemical Innovation (A.A.I), and Winship Cancer Institute (NIH 5P30CA138292).
• Keywords: AMPLIFICATION; Physical Sciences; TUMOR-SUPPRESSOR GENES; PHOSPHORYLATION; Small molecule inhibitor; Oncogenic signaling; CELL LUNG-CANCER; Science & Technology; KINASE KINASE 3; DNA; Pharmacology & Pharmacy; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; INHIBITOR; Protein-protein interaction; High-throughput screening; POOR SURVIVAL; Chemistry, Medicinal; Chemistry, Organic; PATHWAYS; Chemical tool; Chemistry; C-MYC; MYC; MKK3

Abstract

The transcription master regulator MYC plays an essential role in regulating major cellular programs and is a well-established therapeutic target in cancer. However, MYC targeting for drug discovery is challenging. New therapeutic approaches to control MYC-dependent malignancy are urgently needed. The mitogen-activated protein kinase kinase 3 (MKK3) binds and activates MYC in different cell types, and disruption of MKK3-MYC protein–protein interaction may provide a new strategy to target MYC-driven programs. However, there is no perturbagen available to interrogate and control this signaling arm. In this study, we assessed the drugability of the MKK3-MYC complex and discovered the first chemical tool to regulate MKK3-mediated MYC activation. We have designed a short 44-residue inhibitory peptide and developed a cell lysate-based time-resolved fluorescence resonance energy transfer (TR-FRET) assay to discover the first small molecule MKK3-MYC PPI inhibitor. We have optimized and miniaturized the assay into an ultra-high-throughput screening (uHTS) 1536-well plate format. The pilot screen of ~6,000 compounds of a bioactive chemical library followed by multiple secondary and orthogonal assays revealed a quinoline derivative SGI-1027 as a potent inhibitor of MKK3-MYC PPI. We have shown that SGI-1027 disrupts the MKK3-MYC complex in cells and in vitro and inhibits MYC transcriptional activity in colon and breast cancer cells. In contrast, SGI-1027 does not inhibit MKK3 kinase activity and does not interfere with well-known MKK3-p38 and MYC-MAX complexes. Together, our studies demonstrate the drugability of MKK3-MYC PPI, provide the first chemical tool to interrogate its biological functions, and establish a new uHTS assay to enable future discovery of potent and selective inhibitors to regulate this oncogenic complex.