Discovery and functional characterization of a novel small molecule inhibitor of the intracellular phosphatase, SHIP2

Abstract

Background and purpose:The lipid phosphatase known as SH2 domain-containing inositol 5′-phosphatase 2 (SHIP2) plays an important role in the regulation of the intracellular insulin signalling pathway. Recent studies have suggested that inhibition of SHIP2 could produce significant benefits in treatment of type 2 diabetes. However, there were no small molecule SHIP2 inhibitors and we, therefore, aimed to identify this type of compound. Experimental approach: The phosphatase assay with malachite green was used for high-throughput screening. The pharmacological profiles of suitable compounds were further characterized in phosphatase assays, cellular assays and oral administration in normal and diabetic (db/db) mice. Key results: During high-throughput screening, AS1949490 was identified as a potent SHIP2 inhibitor (IC50 = 0.62 mM for SHIP2). This compound was also selective for SHIP2 relative to other intracellular phosphatases. In L6 myotubes, AS1949490 increased the phosphorylation of Akt, glucose consumption and glucose uptake. In FAO hepatocytes, AS1949490 suppressed gluconeogenesis. Acute administration of AS1949490 inhibited the expression of gluconeogenic genes in the livers of normal mice. Chronic treatment of diabetic db/db mice with AS1949490 significantly lowered the plasma glucose level and improved glucose intolerance. These in vivo effects were based in part on the activation of intracellular insulin signalling pathways in the liver. Conclusions and implications:This is the first report of a small molecule inhibitor of SHIP2. This compound will help to elucidate the physiological functions of SHIP2 and its involvement in various diseases, such as type 2 diabetes.

Functional Genome-wide Screen Identifies Pathways Restricting Central Nervous System Axonal Regeneration

“…Innpl1 is also required for signaling by other regeneration genes identified here, such as the HGF receptor Met (Koch et al, 2005). The Ship2 inhibitor AS1949490 (Suwa et al, 2009) dose-dependently increased cortical axon regeneration (Figures 4B and 4C). Therefore, Ship2 is a potential drug target for axonal regeneration therapy.…”

Regulation of PtdIns(3,4,5)P3/Akt signalling by inositol polyphosphate 5-phosphatases

“…Adenoviral expression of SHIP2 in the liver of db/ + mice decreases insulin-stimulated Akt phosphorylation, whereas overexpression of a phosphatase-dead SHIP2 mutant increases insulin-induced Akt phosphorylation [67]. SHIP2 inhibition via AS1949490 treatment of db/db mice enhances liver Akt activity [66].…”

“…Conversely, Ship2 knockout mice are protected from highfat diet-induced obesity and insulin resistance, attributed to increased insulin-stimulated Akt phosphorylation (Table 1) [65]. Loss of SHIP2 phosphatase activity in insulin-resistant db/db mice via oral administration of a SHIP2 phosphatase inhibitor, AS1949490, or via liver-specific overexpression of a SHIP2 phosphatase-dead mutant, increased Akt activity and improved glucose uptake [66,67]. Collectively, these studies suggest SHIP2 lowers insulin-induced PtdIns(3,4,5)P 3 levels to inhibit Akt signalling, despite increasing PtdIns(3,4)P 2 signals; and that loss of SHIP2 5-phosphatase activity increases Akt-mediated glucose uptake in cases of insulin resistance.…”

Inhibition of PI3K Signaling Spurs New Therapeutic Opportunities in Inflammatory/Autoimmune Diseases and Hematological Malignancies

“…Indeed, targeting of multiple INHIBITION OF PI3K IN THE IMMUNE SYSTEM myeloma cells by compounds that target both SHIP-1 and -2 can cause cell death (Fuhler et al, 2012). Compounds that selectively target SHIP-2 have also been reported, including inhibitors of SHIP-2 catalytic activity (Suwa et al, 2009) and a novel cell-impermeant biphenyl 2,3Ј4,5Ј,6-pentakisphosphate (Vandeput et al, 2007). Despite the lack of cell penetration by this latter compound, it has provided an invaluable tool for the study of SHIP-2.…”