Selectivity Profiling and Biological Activity of Novel β-Carbolines as Potent and Selective DYRK1 Kinase Inhibitors

Abstract

DYRK1A is a pleiotropic protein kinase with diverse functions in cellular regulation, including cell cycle control, neuronal differentiation, and synaptic transmission. Enhanced activity and overexpression of DYRK1A have been linked to altered brain development and function in Down syndrome and neurodegenerative diseases such as Alzheimer’s disease. The β-carboline alkaloid harmine is a high affinity inhibitor of DYRK1A but suffers from the drawback of inhibiting monoamine oxidase A (MAO-A) with even higher potency. Here we characterized a series of novel harmine analogs with minimal or absent MAO-A inhibitory activity. We identified several inhibitors with submicromolar potencies for DYRK1A and selectivity for DYRK1A and DYRK1B over the related kinases DYRK2 and HIPK2. An optimized inhibitor, AnnH75, inhibited CLK1, CLK4, and haspin/GSG2 as the only off-targets in a panel of 300 protein kinases. In cellular assays, AnnH75 dose-dependently reduced the phosphorylation of three known DYRK1A substrates (SF3B1, SEPT4, and tau) without negative effects on cell viability. AnnH75 inhibited the cotranslational tyrosine autophosphorylation of DYRK1A and threonine phosphorylation of an exogenous substrate protein with similar potency. In conclusion, we have characterized an optimized β-carboline inhibitor as a highly selective chemical probe that complies with desirable properties of drug-like molecules and is suitable to interrogate the function of DYRK1A in biological studies.

Structure‐Based Design and Synthesis of Harmine Derivatives with Different Selectivity Profiles in Kinase versus Monoamine Oxidase Inhibition

“…Some recent papers described benzothiazole derivatives that showed inhibitory potency and kinase selectivity similar to those of harmine without inhibiting MAO‐A . The decrease in MAO‐A inhibition through N‐substitution of β‐carbolines while maintaining DYRK1A inhibition was also elegantly demonstrated by Becker …”

“…Modification of the ring NH group was achieved by introducing differently functionalized alkyl chains. N-Methyl derivative 7 bearing the smallest substituent in this position retained harmine'sa ctivity against both targets.B yi ncreasing the size of the substituent (see compounds [8][9][10][11][12][13][14][15], we observed as ignificant drop in MAO-A inhibition, whereas the affinity toward DYRK1A remained similar.P ropyl (see compound 8)a nd isopropyl (see compound 9)s ubstitu- tion was equallyt olerated, ase xpected on the basis of the structureo fD YRK1A, as theses ubstituents are projected toward the solvent-exposed area.V ariation in the polarity of the Ns ubstituent in the analogues of 8,a se xpected, did not restoreM AO-A binding buti nsteadl ed to some variations in DYRK1Aa ffinity.E ster-bearingc ompound 10 remained equipotent, whereas benzyl derivative 11 and amide analogue 14 were 6-to 8-fold less potent.T he least potent compound in this series wasa cid derivative 13.T he loss of potency for 13 and 14 might be attributed to desolvation (see compound 4), whereas the benzyl group of 11 might clash with the glycine loop of DYRK1A (omitted from Figure 1f or clarity). These results demonstrate that by proper functionalization of the ring NH group of harmine, one might obtain potent DYRK1Ainhibitors that are devoid of MAO-A inhibition.…”

“…[13,14] The decrease in MAO-A inhibition through N-substitutiono fb-carbolines whilem aintaining DYRK1Ai nhibition was also elegantly demonstratedb y Becker. [15]…”

Genome-Wide Identification and Evolutionary Analysis of Sarcocystis neurona Protein Kinases

“…Inhibition of PfCLK-mediated SR protein phosphorylation impaired blood stage replication and malaria transmission in Plasmodium [59]. The DYRK is implicated in a myriad of cell cycle functions that make this PK, hence an attractive drug target [60]. Other drug targets include MAPKs, which regulate diverse cellular functions, such as tissue morphogenesis, cytoskeletal rearrangements, proliferation, differentiation, survival, immune responses and adaptation/stress-responses [61].…”

A new approach to 1-substituted β-carbolines and isoquinolines utilizing tributyl[(Z)-2-ethoxyvinyl]stannane as a C-3,C-4 building block

“…Improvement of target selectivity and elimination of undesired side effects of harmine is attempted by systematic structure modifications at all edges of the lead structure. Such work has been performed by others [10] and us [11] by direct modification (ring substitution, Nalkylations) of commercially available harmine, or by synthesizing novel 1-substituted β-carbolines following established procedures. The most common approaches to the β-carboline ring system [12] start from tryptamine or tryptophan, and involve construction of the pyridine ring under incorporation of either aldehyde (PictetSpengler reaction) [13] or carboxylic acid (Bischler-Napieralski reaction) [14] building blocks, followed by dehydrogenation of the resulting di-or tetrahydro-β-carbolines.…”