P3‐352: Leucettines, a family of pharmacological inhibitors of DYRKs and CLKs derived from the marine sponge: Natural product Leucettamine B

Abstract

Background Protein kinases catalyze the phosphorylation of proteins, one of the major mechanisms of regulation of cell life. Of the 518 human kinases, the families of DYRKS (dual specificity, tyrosine phosphorylation activated kinases) and CLKS (cdc2-like kinases) are involved in alternative pre-mRNA splicing and Alzheimer's disease/Down syndrome. We here report on the synthesis, optimization and biological characterization of leucettines, a family of kinase inhibitors derived from the marine sponge natural product Leucettamine B.

Methods Stepwise synthesis of analogues starting from the natural structure using an original microwave irradiation supported synthesis protocol, followed by activity testing on 8 purified kinases led to highly potent inhibitors of CLKs and DYRKs. The selectivity of Leucettine L41 was extensively studied by interaction assays, affinity chromatography and catalytic kinase activity assays.

Results Leucettine L41 was co-crystallized with DYRK1A, DYRK2, CLK3 and PIM1. It interacts with key residues located within the ATP-binding pocket of the kinase. Leucettine L41 inhibits the phosphorylation of serine/arginine-rich proteins (SRp), a family of proteins regulating pre-RNA splicing. Indeed leucettine L41 was demonstrated to modulate alternative pre-mRNA splicing in a cell based reporting system as well as in cell culture. Leucettine L41 provides protection against glutamate-induced cell death in cultured mouse HT22 hippocampal cells. It also provides neuroprotection against APP-induced cell death in mouse brain slices. Finally it prevents in vivo cognitive impairments due to intracerebroventricular injection of amyloid-β 25-35.

Conclusions Leucettines should be further explored as pharmacological tools to study and modulate pre-mRNA splicing. Leucettines should also be investigated as potential therapeutic drugs in Alzheimer's disease and in diseases involving abnormal pre-mRNA splicing. References: (1) Debdab, M., Carreaux, F., Renault, S., Soundararajan, M., Fedorov, O., Filippakopoulos, P., Lozach, O., Babault, L., Tahtouh, T., Baratte, B., Ogawa, Y., Hagiwara, M., Eisenreich, A., Rauch, U., Knapp, S., Meijer, L. and Bazureau, J.-P., 2011. Leucettines, a class of potent inhibitors of cdc2-like kinases and dual specificity, tyrosine phosphorylation regulated kinases derived from the marine sponge leucettamine B. Modulation of alternative pre-RNA splicing. J. Med. Chem. 54, 4172-4186.