Discovery of potent, orally bioavailable ERK1/2 inhibitors with isoindolin-1-one structure by structure-based drug design.

Constitutive activation of MAPK (RAS/RAF/MEK/ERK) pathway is frequently observed in many tumors and thus has become an interesting therapeutic target for cancer therapy. Despite the successful development of BRAF and MEK inhibitors in clinic treatment, resistance often appears to re-enhance ERK1/2 signaling. Inspired by the central role of the ERK1/2 signaling cascade in cancer, we describe the scaffold-hopping generation of a series of isoindolin-1-one ERK1/2 inhibitors. Our new compounds could inhibit proliferation of KRAS and BRAF mutant cells lines at low nanomolar concentrations. Compound 22a possesses acceptable pharmacokinetic profiles and showed considerable in vivo antitumor efficacy in a HCT-116 xenograft model, providing a promising basis for further optimization towards clinical ERK1/2 inhibitors.