ARRY-438162 (625 nM) inhibits in vitro osteoclast differentiation with IC50 of 39 nM. ARRY-438162 (10 μM) inhibits in vitro osteoclast resorption with IC50 of 625 nM. ARRY-438162 (2
μM) weakly affects osteoblast differentiation. ARRY-438162 is a recently disclosed potent and selective ATP non-competitive MEK1/2 inhibitor, inhibits pERK in cells with an
IC50 of11 nM. MEK162 (1 μM) combined with MK-2206 (2 μM) completely reverses the resistance of RSK-expressing MCF7
cells.