Definition

An orally bioavailable, non-ATP-competitive, allosteric, small-molecule inhibitor of mitogen-activated protein kinase kinase (MAP2K; MAPK/ERK kinase; MEK) 1 and MEK2, with potential antineoplastic activity. Upon oral administration, MEK inhibitor REC-4881 selectively binds to and inhibits the activity of MEK1/2. This prevents the activation of MEK1/2-dependent effector proteins and transcription factors, which may result in the inhibition of growth factor-mediated cell signaling and tumor cell proliferation. MEK1/2 (MAP2K1/K2) are dual-specificity threonine/tyrosine kinases that play key roles in the activation of the RAS/RAF/MEK/ERK pathway and are often upregulated in a variety of tumor cell types.