A series of cycloalkyl substituted analogues of the natural product sinefungin lacking the amino-acid moiety was designed and synthesized. Two stereoisomers (6-R and 6-S) were separated and their bioactivities examined against EHMT1/2. Of which, compound 14d showed an inhibitory activity against EHMT1/2 (88.9%, IC50 = 21.8 μM for EHMT1 and 77.6%, IC50 = 39.6 μM for EHMT2, respectively) similar to that of sinefungin (100.0%, IC50 = 28.4 μM for EHMT1 and 79.5%, IC50 = 30.1 μM for EHMT2, respectively). Further studies against other methyltransferases such as PRMT1 showed no activity except that 12d displayed about 20% inhibition.Download high-res image (70KB)Download full-size image

Post-translational epigenetic modification of histones is controlled by a number of histone-modifying enzymes. Such modification regulates the accessibility of DNA and the subsequent expression or silencing of a gene. Human histone methyltransferases (HMTs)constitute a large family that includes histone lysine methyltransferases (HKMTs) and histone/protein arginine methyltransferases (PRMTs). There is increasing evidence showing a correlation between HKMTs and cancer pathogenesis. Here, we present an overview of representative HKMTs, including their biological and biochemical properties as well as the profiles of small molecule inhibitors for a comprehensive understanding of HKMTs in drug discovery.

Glucagon receptor antagonists possess a great potential for treatment of type 2 diabetes mellitus. A series of pyrazole-containing derivatives were designed, synthesized and evaluated by biological assays as glucagon receptor antagonists. Most of the compounds exhibited good in vitro efficacy. Two of them, compounds 17f and 17k, displayed relatively potent antagonist effects on glucagon receptors with IC50 values of 3.9 and 3.6 μM, respectively. The possible binding modes of 17f and 17k with the cognate receptor were explored by molecular docking simulation.

The glucagon subfamily of class B G protein-coupled receptors (GPCRs) has been proposed to be a crucial drug target for the tretmaent of type 2 diabetes. The challenges associated with determining the crystal structures of class B GPCRs relate to their large amino termini and the lack of available small molecule ligands to stabilize the receptor proteins. Following our discovery of non-peptidic agonists for glucagon-like peptide-1 receptor (GLP-1R) that have therapeutic effects, we initiated collaborative efforts in structural biology and recently solved the three-dimensional (3D) structure of the human glucagon receptor (GCGR) 7-transmembrane domain, providing in-depth information about the underlying signaling mechanisms. In this review, some key milestones in this endeavor are highlighted, including discoveries of small molecule ligands, their roles in receptor crystallization, conformational changes in transmembrane domains (TMDs) upon activation and structure-activity relationship analyses.

The structure–activity relationship (SAR) study of a 1,2,3,4,4a,9a-hexahydro-1H-xanthene series of selective, human glucocorticoid receptor α (hGRα) antagonists is reported. Compounds were screened using hydroxyapatite-based GR binding and MMTV-Luc co-transfection reporter gene assays. Four different regions of the scaffold were modified to assess the effects on hGRα antagonism and related potency. Compound 8d exhibits an 8-fold better bioactivity than the original hit 1a, as well as an improved chemical stability, which make it a promising lead for the subsequent optimization.A small, non-steroidal molecule, GR antagonist 1a, was identified during a high-throughput screening (HTS) campaign. Following the hit-to-lead optimization, its allyl derivative 8d was obtained as a novel glucocorticoid receptor antagonist.

Eukaryotic elongation factor 2 kinase (eEF2K) inhibitors may aid in the development of new therapeutic agents to combat cancer. Purified human eEF2K was obtained from an Escherichia coli expression system and a luminescence-based high-throughput screening (HTS) assay was developed using MH-1 peptide as the substrate. The luminescent readouts correlated with the amount of adenosine triphosphate remaining in the kinase reaction. This method was applied to a large-scale screening campaign against a diverse compound library and subsequent confirmation studies. Nine initial hits showing inhibitory activities on eEF2K were identified from 56,000 synthetic compounds during the HTS campaign, of which, five were chosen to test their effects in cancer cell lines.In this paper, we describe a luminescence-based high-throughput screening (HTS) assay for eukaryotic elongation factor 2 kinase (eEF2K) which represents a potential target for anti-cancer agents. Our HTS campaign against 56,000 small molecule compounds identified 9 initial hits which were further studied in cancer cell lines.Download full-size image