Identification of Small-Molecule Inhibitors of Human Inositol Hexakisphosphate Kinases by High-Throughput Screening

Abstract

Inositol hexakisphosphate kinases (IP6Ks) catalyze pyrophosphorylation of inositol hexakisphosphate (IP6) into inositol 5-diphospho-1,2,3,4,6-pentakisphosphate (IP7), which is involved in numerous areas of cell physiology including glucose homeostasis, blood coagulation, and neurological development. Inhibition of IP6Ks may be effective for the treatment of Type II diabetes, obesity, metabolic complications, thrombosis, and psychiatric disorders. We performed a high-throughput screen (HTS) of 158 410 compounds for IP6K1 inhibitors using a previously developed ADP-Glo Max assay. Of these, 1206 compounds were found to inhibit IP6K1 kinase activity by more than 25%, representing a 0.8% hit rate. Structural clustering analysis of HTS-active compounds, which were confirmed in the dose–response testing using the same kinase assay, revealed diverse clusters that were feasible for future structure–activity relationship (SAR) optimization to potent IP6K inhibitors. Medicinal chemistry SAR efforts in three chemical series identified potent IP6K1 inhibitors which were further validated in an orthogonal LC-MS IP7 analysis. The effects of IP6K1 inhibitors on cellular IP7 levels were further confirmed and were found to correlate with cellular IP6K1 binding measured by a high-throughput cellular thermal shift assay (CETSA).

Development of Novel IP6K Inhibitors for the Treatment of Obesity and Obesity-Induced Metabolic Dysfunctions

“…Due to low protein yield and assay instability, we were unable to perform reliable ITC analysis for IP6K1 and IP6K3. In addition, we noted that the original IP6K inhibitor TNP inhibits two other inositol phosphate kinases, IPMK and IP3KA, albeit with lower potencies. Therefore, the inhibitory activity of 20 toward recombinant IPMK and IP3KA was determined in vitro by HPLC, with [ 3 H]-Ins­(1,4,5)­P 3 as the substrate (Figure S1).…”

The enzymatic activity of inositol hexakisphosphate kinase controls circulating phosphate in mammals

“…2.7.1.151)] 39 was not evaluated. However, a recent study that used our patent information 18 , which was published while this manuscript was under review, reported the inhibitory potency of SC-919 against IPMK [IPMK/IP6K1 IC 50 ratio of SC-919 (LI-2124 in their report) = 82] 40 , indicating that SC-919 is selective for IP6K. However, further profiling of SC-919 with regard to these parameters both in vitro and in vivo is warranted.…”

Pleiotropic actions of IP6K1 mediate hepatic metabolic dysfunction to promote nonalcoholic fatty liver disease and steatohepatitis

“…Unfortunately, TNP is not a drug-like compound due to structural and other shortcomings and thus can only be used as a pharmacological tool [ 3 , 32 ]. Therefore, efforts are ongoing to develop drug-like IP6K inhibitor compounds [ [67] , [68] , [69] ]. A newly developed IP6K inhibitor has been shown to alleviate kidney fibrosis in a rat model of chronic kidney disease by increasing ATP and reducing hyperphosphatemia [ 70 ].…”