Definition

An orally bioavailable, brain penetrating inhibitor of mitogen-activated protein kinase kinase (MAP2K; MAPKK; MEK), with potential antineoplastic activity. Upon oral administration, MEK inhibitor PF-07799544 specifically targets, binds to and inhibits the catalytic activity of MEK, thereby inhibiting the activation of MEK-dependent effector proteins, including extracellular signal-regulated kinase (ERK), and inhibits the proliferation of tumor cells in which the RAS/RAF/MEK/ERK signaling pathway is overactivated. The threonine/tyrosine protein kinase MEK plays a key role in the RAS/RAF/MEK/ERK signaling pathway, which is frequently upregulated in a variety of tumor cell types and regulates key cellular activities including cell growth, proliferation, survival, differentiation and apoptosis.