O-GlcNAc transferase (OGT) is an essential mammalian enzyme that regulates numerous cellular processes through the attachment of O-linked N-acetylglucosamine (O-GlcNAc) residues to nuclear and cytoplasmic proteins. Its targets include kinases, phosphatases, transcription factors, histones, and many other intracellular proteins. The biology of O-GlcNAc modification is still not well understood and cell-permeable inhibitors of OGT are needed both as research tools and for validating OGT as a therapeutic target. Here we report a small molecule OGT inhibitor, OSMI-1, developed from a high-throughput screening hit. It is cell-permeable and inhibits protein O-GlcNAcylation in several mammalian cell lines without qualitatively altering cell surface N- or O-linked glycans. The development of this molecule validates high-throughput screening approaches for the discovery of glycosyltransferase inhibitors, and further optimization of this scaffold may lead to yet more potent OGT inhibitors useful for studying OGT in animal models.

A new phosphorus-containing dicarbamates, di(N-carbomethoxylaminomethyl)benzyl phosphine oxide was first synthesized from tetrakis(hydroxymethyl)phosphonium sulfate (THPS) via five step reactions (Scheme 1), and its structure was proved by FTIR, ( 1 H, 13 C, and 31 P) NMR, and MS. A series of thermally stable phosphorus-containing polyureas were synthesized via trans-ureation polycondensation of the new monomer with aliphatic diamines, including poly(propylene glycol) bis(2-aminopropyl ether), respectively. All of the above polyureas were fully characterized by inherent viscosity, GPC, solubility tests, and thermogravimetric analysis. The thermal gravimetric analysis results showed that the initial breakdown temperature of all phosphorus-containing polyureas was observed at above 265°C while complete weight loss occurred in the region of 406-465°C, which shows all polyureas have good thermal stability. GPC results showed that the maximum number-average molecular weight of the synthesized polyureas reached 59,100 g mol. The solubility tests results demonstrated that incorporating the ether moieties into the polymer main chain can enhance the solubility of polyureas in organic solvents.