Inhibition of prenylated KRAS in a lipid environment

RAS mutations lead to a constitutively active oncogenic protein that signals through multiple effector pathways. We describe a novel coupled biochemical assaythat measures activation of the effector BRAF by prenylatedKRASG12V in a lipid-dependent manner. Using this assay, we discovered compounds that block biochemical and cellular functions of KRASG12V with low single-digit micromolar potency. We characterized the structural basis for inhibition using NMR methods and showed that the compounds stabilized the inactive conformation of KRASG12V. When assaysutilize full-length, prenylated KRASin a lipid environment, cellular, biophysical, and biochemical potencieswere similar, which demonstrates the importance of using biologically relevant constructs and assayconditions. These assaysand ligands are valuable tools for further study of KRASinhibition and drug discovery.