The Nitro Group Reshapes the Effects of Pyrido[3,4-g]quinazoline Derivatives on DYRK/CLK Activity and RNA Splicing in Glioblastoma Cells

Serine-threonine protein kinases of the DYRK and CLK families regulate a variety of vital cellular functions. In particular, these enzymes phosphorylate proteins involved in pre-mRNA splicing. Targeting splicing with pharmacological DYRK/CLK inhibitors emerged as a promising anticancer strategy. Investigation of the pyrido[3,4-g]quinazoline scaffold led to the discovery of DYRK/CLK binders with differential potency against individual enzyme isoforms. Exploring the structure-activity relationship within this chemotype, we demonstrated that two structurally close compounds, pyrido[3,4-g]quinazoline-2,10-diamine 1 and 10-nitro pyrido[3,4-g]quinazoline-2-amine 2, differentially inhibited DYRK1-4 and CLK1-3 protein kinases in vitro. Unlike compound 1, compound 2 efficiently inhibited DYRK3 and CLK4 isoenzymes at nanomolar concentrations. Quantum chemical calculations, docking and molecular dynamic simulations of complexes of 1 and 2 with DYRK3 and CLK4 identified a dramatic difference in electron donor-acceptor properties critical for preferential interaction of 2 with these targets. Subsequent transcriptome and proteome analyses of patient-derived glioblastoma (GBM) neurospheres treated with 2 revealed that this compound impaired CLK4 interactions with spliceosomal proteins, thereby altering RNA splicing. Importantly, 2 affected the genes that perform critical functions for cancer cells including DNA damage response, p53 signaling and transcription. Altogether, these results provide a mechanistic basis for the therapeutic efficacy of 2 previously demonstrated in in vivo GBM models.

New pyrido[3,4-g]quinazoline derivatives as CLK1 and DYRK1A inhibitors: synthesis, biological evaluation and binding mode analysis

Cdc2-like kinase 1 (CLK1) and dual specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) are involved in the regulation of alternative pre-mRNA splicing. Dysregulation of this process has been linked to cancer progression and neurodegenerative diseases, making CLK1 and DYRK1A important therapeutic targets. Here we describe the synthesis of new pyrido[3,4-g]quinazoline derivatives and the evaluation of the inhibitory potencies of these compounds toward CDK5, CK1, GSK3, CLK1 and DYRK1A. Introduction of aminoalkylamino groups at the 2-position resulted in several compounds with low nanomolar affinity and selective inhibition of CLK1 and/or DYRK1A. Their evaluation on several immortalized or cancerous cell lines showed varying degree of cell viability reduction. Co-crystal structures of CLK1 with two of the most potent compounds revealed two alternative binding modes of the pyrido[3,4-g]quinazoline scaffold that can be exploited for future inhibitor design.

Regioselective cycloaddition of potassium alkynyltrifluoroborates with 3-azetidinones and 3-oxetanone by nickel-catalysed C–C bond activation

The nickel-catalysed (4+2) cycloaddtion of potassium alkynyltrifluoroborates and 3-azetidinones and 3-oxetanone gives only one regioisomer for all alkyne substituents.

Synthesis and preliminary in vitro kinase inhibition evaluation of new diversely substituted pyrido[3,4-g]quinazoline derivatives

The synthesis of new diversely substituted pyrido[3,4-g]quinazolines is described. The inhibitory potencies of prepared compounds toward a panel of five CMGC protein kinases (CDK5, CLK1, DYRK1A, CK1, GSK3), that are known to play a potential role in Alzheimer's disease, were evaluated. The best overall kinase inhibition profile was found for nitro compound 4 bearing an ethyl group at the 5-position.

Heteroaromatic Pim Kinase Inhibitors Containing a Pyrazole Moiety

This review, of the literature published between 2010 and 2015 reports that molecules containing a non-fused and/or fused pyrazole moiety could exhibit very potent activity toward Pim kinases, including the inhibition of cellular Bad phosphorylation as well as antiproliferative activity against various cancer cells. Even if Pim kinase inhibitors currently in clinical trial do not exhibit a pyrazole moiety, heteroaromatic kinase inhibitors containing an indazole part such as Axitinib and Pazopanib already reached the market. Therefore, one can imagine that in the future, heteroaromatic derivatives inhibiting Pim kinases including pyrazoles could be identified and used for their diagnostic and/or therapeutic potential alone or in combination with other drugs for the diseases in which Pim kinases are involved.