Discovery of Bifunctional Oncogenic Target Inhibitors against Allosteric Mitogen-Activated Protein Kinase (MEK1) and Phosphatidylinositol 3-Kinase (PI3K)

摘要

The synthesis of a series of single entity, bifunctional MEK1/PI3K inhibitors achieved by covalent linking of structural analogs of the ATP-competitive PI3K inhibitor ZSTK474 and the ATP-noncompetitive MEK inhibitor PD0325901 is described. Inhibitors displayed potent in vitro inhibition of MEK1 (0.015 < IC50 (nM) < 56.7) and PI3K (54 < IC50 (nM) < 341) in enzymatic inhibition assays. Concurrent MEK1 and PI3K inhibition was demonstrated with inhibitors >9 and >14 in two tumor cell lines (A549, D54). Inhibitors produced dose-dependent decreased cell viability similar to the combined administration of equivalent doses of ZSTK474 and PD0325901. In vivo efficacy of >14 following oral administration was demonstrated in D54 glioma and A549 lung tumor bearing mice. Compound >14 showed a 95% and 67% inhibition of tumor ERK1/2 and Akt phosphorylation, respectively, at 2 h postadministration by Western blot analysis, confirming the bioavailability and efficacy of this bifunctional inhibitor strategy toward combined MEK1/PI3K inhibition.