[CAS NO. 68302-57-8]  Amlexanox (AA-673)

Dose-response relationship of amlexanox inhibition of IKK-ɛ and TBK1 activity as determined by MBP phosphorylation showing an IC50 of approximately 1-2 μM. Amlexanox also blocks the activity of TBK1 at approximately the same concentrations but has no effect on IKK-α or IKK-β and at these concentrations do not block any other kinases from a broad panel representing most kinase families. Inhibition of IKK-ɛ or TBK1 by amlexanox is competitive for its substrate ATP, indicating that it interacts with the enzymes in the ATP-binding site. Amlexanox increases the phosphorylation of TBK1 at Ser172 in 3T3-L1 adipocytes and blocks polyinosinic:polycytidylic acid (poly I:C)-stimulated phosphorylation of interferon responsive factor-3 (IRF3), a presumed substrate of IKK-ɛ and TBK1.