Discovery of MEK/PI3K dual inhibitor via structure-based virtual screening.

Mitogen/extracellular signal-regulated kinase (MEK) and phosphoinositide 3-kinase (PI3Kα) are considered to be promising targets for the development of anticancer therapeutics. We report the first example of the successful application of structure-based virtual screening to identify novel inhibitors of MEK with IC(50) values ranging from 1 to 25 μM. One of the four newly identified MEK inhibitors was found to be also a potent inhibitor of PI3Kα with submicromolar inhibitory activity (IC(50)=0.3 μM). Because this dual inhibitor was screened for having desirable physicochemical properties as a drug candidate as well as the high inhibitory activities against MEK and PI3Kα, it warrants further development through structure-activity relationship (SAR) studies to optimize the inhibitory and anticancer activities. Structural features relevant to the stabilization of the dual inhibitor in the ATP-binding sites of MEK1 and PI3Kα are addressed in detail.