AKT is a key node in the most frequently deregulated signaling network in human cancer. AZD5363, a novel pyrrolopyrimidine-derived compound, inhibited all AKT isoforms with a potency of 10 nmol/L or less and inhibited phosphorylation of AKT substrates in cells with a potency of approximately 0.3 to 0.8 mmol/L. AZD5363 monotherapy inhibited the proliferation of 41 of 182 solid and hematologic tumor cell lines with a potency of 3 mmol/L or less. Cell lines derived from breast cancers showed the highest frequency of sensitivity. There was a significant relationship between the presence of PIK3CA and/or PTEN mutations and sensitivity to AZD5363 and between RAS mutations and resistance. Oral dosing of AZD5363 to nude mice caused doseand time-dependent reduction of PRAS40, GSK3b, and S6 phosphorylation in BT474c xenografts (PRAS40 phosphorylation EC 50 $ 0.1 mmol/L total plasma exposure), reversible increases in blood glucose concentrations, and dose-dependent decreases in 2[18F]fluoro-2-deoxy-D-glucose ( 18 F-FDG) uptake in U87-MG xenografts. Chronic oral dosing of AZD5363 caused dose-dependent growth inhibition of xenografts derived from various tumor types, including HER2þ breast cancer models that are resistant to trastuzumab. AZD5363 also significantly enhanced the antitumor activity of docetaxel, lapatinib, and trastuzumab in breast cancer xenografts. It is concluded that AZD5363 is a potent inhibitor of AKT with pharmacodynamic activity in vivo, has potential to treat a range of solid and hematologic tumors as monotherapy or a combinatorial agent, and has potential for personalized medicine based on the genetic status of PIK3CA, PTEN, and RAS. AZD5363 is currently in phase I clinical trials. Mol Cancer Ther; 11(4); 873-87. Ó2012 AACR.

Human thymidine phosphorylase (HTP), also known as platelet-derived endothelial cell growth factor (PD-ECGF), is overexpressed in certain solid tumors where it is linked to poor prognosis. HTP expression is utilized for certain chemotherapeutic strategies and is also thought to play a role in tumor angiogenesis. We determined the structure of HTP bound to the small molecule inhibitor 5-chloro-6-[1-(2-iminopyrrolidinyl) methyl] uracil hydrochloride (TPI). The inhibitor appears to mimic the substrate transition state, which may help explain the potency of this inhibitor and the catalytic mechanism of pyrimidine nucleotide phosphorylases (PYNPs). Further, we have confirmed the validity of the HTP structure as a template for structure-based drug design by predicting binding affinities for TPI and other known HTP inhibitors using in silico docking techniques. This work provides the first structural insight into the binding mode of any inhibitor to this important drug target and forms the basis for designing novel inhibitors for use in anticancer therapy.

Wide-ranging exploration of analogues of an ATP-competitive pyrrolopyrimidine inhibitor of Akt led to the discovery of clinical candidate AZD5363, which showed increased potency, reduced hERG affinity, and higher selectivity against the closely related AGC kinase ROCK. This compound demonstrated good preclinical drug metabolism and pharmacokinetics (DMPK) properties and, after oral dosing, showed pharmacodynamic knockdown of phosphorylation of Akt and downstream biomarkers in vivo, and inhibition of tumor growth in a breast cancer xenograft model.

Although various syntheses of the nucleic acid bases exist and ribose is a product of the formose reaction, no prebiotically plausible methods for attaching pyrimidine bases to ribose to give nucleosides have been described. Kinetic and thermodynamic factors are thought to mitigate against such condensation reactions in aqueous solution. This inability to produce pyrimidine nucleosides and hence nucleotides is a major stumbling block of the "RNA World" hypothesis and has led to suggestions of alternative nucleic acids as evolutionary precursors to RNA. Here, we show that a process in which the base is assembled in stages on a sugar phosphate can produce cytidine nucleotides. The sequential action of cyanamide and cyanoacetylene on arabinose-3-phosphate produces cytidine-2',3'-cyclophosphate and arabinocytidine-3'-phosphate.

We have determined the solution structure of the C‐terminal SH2 domain of the p85 alpha subunit of human phosphatidylinositol (PI) 3‐kinase (EC 2.7.1.137) in complex with a phosphorylated tyrosine pentapeptide sequence from the platelet‐derived growth factor receptor using heteronuclear nuclear magnetic resonance spectroscopy. Overall, the structure is similar to other SH2 domain complexes, but displays different detail interactions within the phosphotyrosine binding site and in the recognition site for the +3 methionine residue of the peptide, the side chain of which inserts into a particularly deep and narrow pocket which is displaced relative to that of other SH2 domains. The contacts made within this +3 pocket provide the structural basis for the strong selection for methionine at this position which characterizes the SH2 domains of PI3‐kinase. Comparison with spectral and structural features of the uncomplexed domain shows that the long BG loop becomes less mobile in the presence of the bound peptide. In contrast, extreme resonance broadening encountered for most residues in the beta D’, beta E and beta F strands and associated connecting loops of the domain in the absence of peptide persists in the complex, implying conformational averaging in this part of the molecule on a microsecond‐to‐millisecond time scale.