Discovery of indole inhibitors of chemokine receptor 9 (CCR9).

Irritable bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) are serious chronic diseases affecting millions of patients worldwide. Studies of human chemokine biology has suggested C-C chemokine receptor 9 (CCR9) may be a key mediator of pro-inflammatory signaling. Discovery of agents that inhibit CCR9 may lead to new therapies for CD and UC patients. Herein we describe the evolution of a high content screening hit (1) into potent inhibitors of CCR9, such as azaindole 12.

Fragment-based discovery of DNA gyrase inhibitors targeting the ATPase subunit of GyrB.

Inhibitors of the ATPase function of bacterial DNA gyrase, located in the GyrB subunit and its related ParE subunit in topoisomerase IV, have demonstrated antibacterial activity. In this study we describe an NMR fragment-based screening effort targeting Staphylococcus aureus GyrB that identified several attractive and novel starting points with good ligand efficiency. Fragment hits were further characterized using NMR binding studies against full-length S. aureus GyrB and Escherichia coli ParE. X-ray co-crystal structures of select fragment hits confirmed binding and suggested a path for medicinal chemistry optimization. The identification, characterization, and elaboration of one of these fragment series to a 0.265 µM inhibitor is described herein.

Design of selective, ATP-competitive inhibitors of Akt.

This paper describes the design and synthesis of novel, ATP-competitive Akt inhibitors from an elaborated 3-aminopyrrolidine scaffold. Key findings include the discovery of an initial lead that was modestly selective and medicinal chemistry optimization of that lead to provide more selective analogues. Analysis of the data suggested that highly lipophilic analogues would likely suffer from poor overall properties. Central to the discussion is the concept of optimization of lipophilic efficiency and the ability to balance overall druglike propeties with the careful control of lipophilicity in the lead series. Discovery of the nonracemic amide series and subsequent modification produced an advanced analogue that performed well in advanced preclinical assays, including xenograft tumor growth inhibition studies, and this analogue was nominated for clinical development.

Synthesis and structure based optimization of novel Akt inhibitors.

Based on a high throughput screening hit, pyrrolopyrimidine inhibitors of the Akt kinase are explored. X-ray co-crystal structures of two lead series results in the understanding of key binding interactions, the design of new lead series, and enhanced potency. The syntheses of these series and their biological activities are described. Spiroindoline 13j is found to have an Akt1 kinase IC(50) of 2.4+/-0.6 nM, Akt cell potency of 50+/-19 nM, and provides 68% inhibition of tumor growth in a mouse xenograft model (50 mg/kg, qd, po).

The discovery of highly selective erbB2 (Her2) inhibitors for the treatment of cancer.

The synthesis and biological evaluation of potent and selective inhibitors of the erbB2 kinase is presented. Based on the 4-anilinoquinazoline chemotype, the syntheses of several new series of erbB2 inhibitors are described with quinazoline and pyrido[4,3-d]pyrimidine cores. The vast majority of these compounds are found to be >100x selective over the closely related EGFR kinase. Two lead compounds are further shown to have low clearance and moderate bioavailability in rat.

Discovery of novel isothiazole inhibitors of the TrkA kinase: structure-activity relationship, computer modeling, optimization, and identification of highly potent antagonists.

The design, synthesis, and biological evaluation of potent inhibitors of the TrkA kinase is presented. A homology model is created to aid in the enhancement of potency and selectivity of isothiazole inhibitors found during a high-throughput screen. Three different syntheses are utilized to make diverse analogs within this series. Aminoheterocycles are found to be good urea surrogates, whereas bicyclic substituents on the C3 thio group were found to be extremely potent TrkA inhibitors in kinase and cell assays.

The Hedgehog signaling pathway as a target for anticancer drug discovery.

The Hedgehog (Hh) signaling pathway directs the development of multiple tissues during embryonic development, and contributes to tissue homeostasis in adults. Deficient Hh signaling results in defective embryogenesis; conversely, excessive Hh signaling is associated with an inherited cancer predisposition syndrome (Gorlin Syndrome), and a growing list of sporadic human cancers. It is now clear that multiple components of "The Hh Pathway" can be altered in tumors. The Hhs are morphogens that signal through effectors that are largely unprecedented in drug discovery, with many key concepts derived from studies in Drosophila melanogaster. However, studies in tumor cell lines have recently identified targets that can be exploited for the discovery of human Hh antagonists, with additional targets likely to emerge as the human pathway is further defined. Here, we review basic aspects of Hh signal transduction, with an emphasis on molecular targets for drug discovery. The use of first-generation Hh antagonists such as cyclopamine will also be discussed; such agents remain invaluable in ongoing efforts to validate drug discovery assays and survey tumor lines for Hh dependence. The various types and frequencies of Hh signaling defects in different human tumors will also be reviewed, as will the status of medicinal chemistry efforts to discover novel Hh antagonists. In section VI, we review assays from the literature that could be utilized to discover new Hh antagonists for the treatment of cancer.

The practical synthesis of a novel and highly potent analogue of bryostatin.

Macrocycle 1 is a new highly potent analogue of bryostatin 1, a promising anti-cancer agent currently in human clinical trials. In vitro, 1 displays picomolar affinity for PKC and exhibits over 100-fold greater potency than bryostatin 1 when tested against various human cancer cell lines. Macrocycle 1 can be generated in clinically required amounts by chemical synthesis in only 19 steps (LLS) and represents a new clinical lead for the treatment of cancer.