HG-9-91-01

HG-9-91-01 is a potent and highly selective salt-inducible kinase (SIK) inhibitor with IC₅₀s of 0.92 nM, 6.6 nM and 9.6 nM for SIK1, SIK2 and SIK3 respectively. IC50 & Target: IC50: 0.92/6.6/9.6 nM (SIK1/2/3)^[1] In Vitro: HG-9-91-01 inhibits a number of protein tyrosine kinases that possess a threonine residue at the gatekeeper site, such as Src family members (Src, Lck, and Yes), BTK, and the FGF and Ephrin receptors^[1]. HG-9-91-01 demonstrates a strong correlation between the potency of SIK2 inhibition and enhanced IL-10 production. In agreement with these reports, pretreating BMDCs with HG-9-91-01, a recently described inhibitor of SIK1-3, along with several other kinases, results in concentration-dependent potentiation of zymosan-induced IL-10 production with an EC₅₀ ~200 nM and a maximum effect similar to that observed with PGE₂^[2]. HG-9-91-01 has more than a 100-fold greater potency against SIKs than AMPK (IC₅₀=4.5 μM) in a cell-free assay. HG-9-91-01 treatment dose dependently increased mRNA expression of Pck1 and G6pc and that effect is similar in cells treated with 4 μM HG-9-91-01. Consistent with this observation, there is also a dose-dependent increase in glucose production following HG-9-91-01 treatment^[3].