ro-4927350.

RO4927350 is a potent and highly selective non-ATP-competitive MEK1/2 inhibitor. RO4927350 selectively blocks the MAPK pathway signaling both in vitro and in vivo, which results in significant antitumor efficacy in a broad spectrum of tumor models. RO4927350 inhibits not only ERK1/2 but also MEK1/2 phosphorylation. In cancer cells, high basal levels of phospho-MEK1/2 rather than phospho-ERK1/2 seem to correlate with greater sensitivity to RO4927350. Furthermore, RO4927350 prevents a feedback increase in MEK phosphorylation, which has been observed with other MEK inhibitors. RO4927350 represents a novel therapeutic modality in cancers with aberrant MAPK pathway activation.