MSC-1186, a Highly Selective Pan-SRPK Inhibitor Based on an Exceptionally Decorated Benzimidazole-Pyrimidine Core

• Published in: Journal of medicinal chemistry 2023-01, Vol.66 (1), p.837-854
• Main Authors: Schröder, Martin, Leiendecker, Matthias, Grädler, Ulrich, Braun, Juliane, Blum, Andreas, Wanior, Marek, Berger, Benedict-Tilman, Krämer, Andreas, Müller, Susanne, Esdar, Christina, Knapp, Stefan, Heinrich, Timo
• Format: Article
• Language: English
• Subjects: Benzimidazoles - pharmacology; Phosphorylation; Protein Serine-Threonine Kinases; Pyrimidines - pharmacology
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/acs.jmedchem.2c01705

The highly conserved catalytic sites in protein kinases make it difficult to identify ATP competitive inhibitors with kinome-wide selectivity. Serendipitously, during a dedicated fragment campaign for the focal adhesion kinase (FAK), a scaffold that had lost its initial FAK affinity showed remarkable potency and selectivity for serine-arginine-protein kinases 1–3 (SRPK1–3). Non-conserved interactions with the uniquely structured hinge region of the SRPK family were the key drivers of the exclusive selectivity of the discovered fragment hit. Structure-guided medicinal chemistry efforts led to the SRPK inhibitor MSC-1186, which fulfills all hallmarks of a reversible chemical probe, including nanomolar cellular potency and excellent kinome-wide selectivity. The combination of MSC-1186 with CDC2-like kinase (CLK) inhibitors showed additive attenuation of SR-protein phosphorylation compared to the single agents. MSC-1186 and negative control (MSC-5360) are chemical probes available via the Structural Genomics Consortium chemical probe program (https://www.sgc-ffm.uni-frankfurt.de/).