Comparative Efficacy and Selectivity of Pharmacological Inhibitors of DYRK and CLK Protein Kinases

Abstract

Dual-specificity, tyrosine phosphorylation-regulated kinases (DYRKs) and cdc2-like kinases (CLKs) play a large variety of cellular functions and are involved in several diseases (cognitive disorders, diabetes, cancers, etc.). There is, thus, growing interest in pharmacological inhibitors as chemical probes and potential drug candidates. This study presents an unbiased evaluation of the kinase inhibitory activity of a library of 56 reported DYRK/CLK inhibitors on the basis of comparative, side-by-side, catalytic activity assays on a panel of 12 recombinant human kinases, enzyme kinetics (residence time and K d), in-cell inhibition of Thr-212-Tau phosphorylation, and cytotoxicity. The 26 most active inhibitors were modeled in the crystal structure of DYRK1A. The results show a rather large diversity of potencies and selectivities among the reported inhibitors and emphasize the difficulties to avoid “off-targets” in this area of the kinome. The use of a panel of DYRKs/CLKs inhibitors is suggested to analyze the functions of these kinases in cellular processes.

Leucettinibs, a Class of DYRK/CLK Kinase Inhibitors Inspired by the Marine Sponge Natural Product Leucettamine B

“…Intermediate activity (IC 50 : 0.1−1.0 μM) was observed with 6-benzo(1,2,3)thiadiazol-6-yl (3,18,33), 2-methyl-benzothiazol-6-yl (4,19,34), 2,3-dihydro-benzofuran-5-yl (7,22,37), and N1methylated indazol-5-yl (12,27,42). High kinase inhibitory activity (IC 50 < 0.1−0.2 μM) was observed with the following heteroaryl systems: 5-benzodioxol-5-yl (1, 16, 31), benzothiazol-6-yl (2,17,32), benzoxazol-6-yl (6,21,36), benzimidazol-5-yl (8,23,38), N1-methylated benzimidazol-6-yl (9,24,39), indazol-5-yl (11,26,41), and N2-methylated indazol-5-yl (13,28,43). The high potency of these heterocycles was associated with the possibility of forming a strong H-bond linking Leucine 241 and a nitrogen or an oxygen atom at position A of the benzodioxol-5-yl, benzothiazol-6-yl, benzoxazol-6-yl, benzimidazol-5-yl, N1-methylated benzimidazol-6-yl, indazol-5-yl, and N2-methylated indazol-5-yl, as illustrated with the molecular docking of compound 32 within the ATP-binding pocket of DYRK1A (see below).…”

“…As a result, we initiated molecular modeling to gain a better understanding of the interactions (Figure ). The binding mode of Leucettinib-92 ( 32 ) was investigated based on the co-crystal structure of Leucettine-41 in complex with DYRK1A (PDB code: 4AZE) (briefly described in the Supplementary Information of ref ). In the adenine region, the benzothiazol-6-yl acts as a hinge binder through a strong 2.1 Å hydrogen bond between the scaffold’s nitrogen and the backbone’s N–H of Leu241 in addition to a weak hydrogen bond between the polarized C7–H of the scaffold and the backbone’s carbonyl of Glu239.…”

“…Leucettinibs constitute interesting biological tools, and iso-Leucettinibs, as kinase inactive isomers, are quite appropriate control reagents. They can also help to tackle the involvement of DYRKs and CLKs in biological processes, and they need to be complemented by the use of other chemically different inhibitors 6 and specific molecular biology gene inactivating tools (siRNA, shRNA). Furthermore, Leucettinibs and control iso-Leucettinibs can be immobilized through a polyethylene glycol linker tethered to agarose beads, thereby providing affinity chromatography reagents for the purification and identification of Leucettinib targets in various cells, tissues, and organs.…”

“…Furthermore, DYRKs and CLKs appear as potential therapeutic targets in various pathologies (reviews in refs − ), encouraging the scientific community to search for and optimize pharmacological of these kinases. More than 60 DYRK/CLK inhibitors have been described, and most of them have recently been reviewed and compared side-by-side in terms of potency and selectivity . DYRK1A in particular has been investigated quite extensively as a potential therapeutic target given its implication in Down syndrome (DS), ,− Alzheimer’s disease (AD), ,− diabetes, ,− viral infections, − osteoarthritis and tendinopathy, , myocardial infarction, , and various cancers including acute lymphoblastic leukemia, acute megakaryoblastic leukemia, − glioblastoma, − and pancreatic cancer − (reviews in refs , ).…”

Chemical, Biochemical, Cellular, and Physiological Characterization of Leucettinib-21, a Down Syndrome and Alzheimer’s Disease Drug Candidate

“…In this context, the search for, optimization and biological characterization of DYRK1A inhibitors has been quite intense during the past few years (see reviews in refs and − ). A comparative study of 56 reported DYRKs/CLKs inhibitors has been published recently which describes the potency and selectivity of most of the reported inhibitors …”