MK-886

MK-886, an inhibitor of the 5-lipoxygenase-activating protein (FLAP), potently suppresses leukotriene biosynthesis in intact cells and is frequently used to define a role of the 5-lipoxygenase (EC 1.13.11.34) pathway in cellular or animal models of inflammation, allergy, cancer, and cardiovascular disease. MK-886 inhibits isolated COX-1 (IC50=8 μM) and blocks the formation of the COX-1-derived products 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid (12-HHT) and thromboxane B2 in washed human platelets in response to collagen as well as from exogenous arachidonic acid (IC50=13–15 μM).Isolated COX-2 was less affected (IC50=58 μM), and in A549 cells, MK-886 (33 μM) failed to suppress COX-2-dependent 6-ketoprostaglandin (PG)F1α formation. MK-886 (10 μM) inhibits COX-1-mediated platelet aggregation induced by collagen or arachidonic acid whereas thrombin- or U-46619-induced (COX-independent) aggregation is not affected^[1].

IL-1β-stimulated A549 cells (5×10⁶/ml) are pre-incubated with MK-886 (MK, 33 μM), or vehicle (DMSO) for 15 min prior to the addition of 30 μM arachidonic acid. After 15 min at 37 °C, the amount of released 6-keto PGF1α was assessed by ELISA as described in the Materials and methods section.

Repeated daily i.p. injections of MK-886 results in increased GluR1 phosphorylation in brain samples obtained from the prefrontal cortex. In contrast, a single injection of MK-886 does not alter cortical GluR1 phosphorylation^[2].