Structure-based optimization of potent, selective, and orally bioavailable CDK8 inhibitors discovered by high-throughput screening

The mediator complex-associated cyclin dependent kinase CDK8 regulates beta-catenin-dependent transcription following activation of WNT signaling. Multiple lines of evidence suggest CDK8 may act as an oncogene in the development of colorectal cancer. Here we describe the successful optimization of an imidazo-thiadiazole series of CDK8 inhibitors that was identified in a high-throughput screening campaign and further progressed by structure-based design. In several optimization cycles, we improved the microsomal stability, potency, and kinase selectivity. The initial imidazo-thiadiazole scaffold was replaced by a 3-methyl-1H-pyrazolo[3,4-b]-pyridine which resulted in compound 25 (MSC2530818) that displayed excellent kinase selectivity, biochemical and cellular potency, microsomal stability, and is orally bioavailable. Furthermore, we demonstrated modulation phospho-STAT1, a pharmacodynamic biomarker of CDK8 activity, and tumor growth inhibition in an APC mutant SW620 human colorectal carcinoma xenograft model after oral administration. Compound 25 demonstrated suitable potency and selectivity to progress into preclinical in vivo efficacy and safety studies

2,8-Disubstituted-1,6-Naphthyridines and 4,6-Disubstituted-Isoquinolines with Potent, Selective Affinity for CDK8/19

We demonstrate a designed scaffold-hop approach to the discovery of 2,8-disubstituted-1,6-naphthyridine- and 4,6-disubstituted-isoquinoline-based dual CDK8/19 ligands. Optimized compounds in both series exhibited rapid aldehyde oxidase-mediated metabolism, which could be abrogated by introduction of an amino substituent at C5 of the 1,6-naphthyridine scaffold or at C1 of the isoquinoline scaffold. Compounds 51 and 59 were progressed to in vivo pharmacokinetic studies, and 51 also demonstrated sustained inhibition of STAT1SER727 phosphorylation, a biomarker of CDK8 inhibition, in an SW620 colorectal carcinoma human tumor xenograft model following oral dosing

The Chalcid Fly in Alfalfa Seed

"The clover-seed chalcis fly which is generally termed the alfalfa-seed chalcis-fly by alfalfa-seed growers, has been increasing so rapidly that its destructive work is now causing a large annual loss, and in some sections even threatening the production of alfalfa seed.... This bulletin will serve to give the alfalfa-seed grower a general knowledge of the chalcis-fly, together with such information as will direct him in adopting measures for reducing the large annual loss due to it work." -- p. 1-

[Max Eckert] / Ferd. Urbahns

Appartient à l’ensemble documentaire : PhoPortr

The clover and alfalfa seed chalcis-fly /

no.812 (1920

The spike-horned leaf-miner, an enemy of grains and grasses /

no.432 (1916