Discovery and Computational Analyses of Novel Small Molecule Zika Virus Inhibitors.

Zika virus (ZIKV), one of the flaviviruses, has attracted worldwide attention since its large epidemics around Brazil. Association of ZIKV infection with microcephaly and neurological problems such as Guillain-Barré syndrome has prompted intensive pathological investigations. However, there is still a long way to go on the discovery of effective anti-ZIKV therapeutics. In this study, an in silico screening of the National Cancer Institute (NCI) diversity set based on ZIKV NS3 helicase was performed using a molecular docking approach. Selected compounds with drug-like properties were subjected to cell-based antiviral assays resulting in the identification of two novel lead compounds (named Compounds 1 and 2). They inhibited ZIKV infection with IC50 values at the micro-molar level (8.5 µM and 15.2 µM, respectively). Binding mode analysis, absolute binding free energy calculation, and structure-activity relationship studies of these two compounds revealed their possible interactions with ZIKV NS3 helicase, suggesting a mechanistic basis for further optimization. These two novel small molecules may represent new leads for the development of inhibitory drugs against ZIKV.

Virtual Screening, Biological Evaluation, and 3D-QSAR Studies of New HIV-1 Entry Inhibitors That Function via the CD4 Primary Receptor.

Human immunodeficiency virus type 1 (HIV-1) is responsible for the majority of HIV infections worldwide, and we still lack a cure for this infection. Blocking the interaction of HIV-1 and its primary receptor CD4 is one strategy for identifying new anti-HIV-1 entry inhibitors. Here we report the discovery of a novel ligand that can inhibit HIV-1 entry and infection via CD4. Biological and computational analyses of this inhibitor and its analogs, using bioactivity evaluation, Rule of Five (RO5), comparative molecular field analysis (CoMFA)/comparative molecular similarity index analysis (CoMSIA) models, and three-dimensional quantitative structure-activity relationship (3D-QSAR), singled out compound 3 as a promising lead molecule for the further development of therapeutics targeting HIV-1 entry. Our study demonstrates an effective approach for employing structure-based, rational drug design techniques to identify novel antiviral compounds with interesting biological activities.

Design, synthesis, and biological characterization of novel PEG-linked dimeric modulators for CXCR4.

CXCR4 dimerization has been widely demonstrated both biologically and structurally. This paper mainly focused on the development of structure-based dimeric ligands that target CXCL12-CXCR4 interaction and signaling. This study presents the design and synthesis of a series of [PEG]n linked dimeric ligands of CXCR4 based on the knowledge of the homodimeric crystal structure of CXCR4 and our well established platform of chemistry and bioassays for CXCR4. These new ligands include [PEG]n linked homodimeric or heterodimeric peptides consisting of either two DV3-derived moieties (where DV3 is an all-d-amino acid analog of N-terminal modules of 1-10 (V3) residues of vMIP-II) or hybrids of DV3 moieties and CXCL121-8. Among a total of 24 peptide ligands, four antagonists and three agonists showed good CXCR4 binding affinity, with IC50 values of <50nM and <800nM, respectively. Chemotaxis and calcium mobilization assays with SUP-T1 cells further identified two promising lead modulators of CXCR4: ligand 4, a [PEG3]2 linked homodimeric DV3, was an effective CXCR4 antagonist (IC50=22nM); and ligand 21, a [PEG3]2 linked heterodimeric DV3-CXCL121-8, was an effective CXCR4 agonist (IC50=407nM). These dimeric CXCR4 modulators represent new molecular probes and therapeutics that effectively modulate CXCL12-CXCR4 interaction and function.

[Progress in the studies on neuronal nitric oxide synthase inhibitors].

Nitric oxide (NO), which is involved in the regulation of the cardiovascular system, nervous system, immune system, reproductive system, digestive system and other physiological activities, is an important biological substance with activity. Under normal physiological conditions, neuronal nitric oxide synthase (nNOS) can precisely regulate the nervous system NO production, release, diffusion and inactivation processes. But an excess of NO associates with the development of cerebral ischemia, Alzheimer's and Parkinson's psychosis nervous system diseases, while inhibition of nNOS activity can regulate the content of NO in vivo, and produce a therapeutic effect on some of the nervous system diseases. This review mainly describes the structure and regulation of nNOS and recent developments of small molecule inhibitors of nNOS.

Design, synthesis, and biological characterization of a new class of symmetrical polyamine-based small molecule CXCR4 antagonists.

CXCR4, a well-studied coreceptor of human immunodeficiency virus type 1 (HIV-1) entry, recognizes its cognate ligand SDF-1α (also named CXCL12) which plays many important roles, including regulating immune cells, controlling hematopoietic stem cells, and directing cancer cells migration. These pleiotropic roles make CXCR4 an attractive target to mitigate human disorders. Here a new class of symmetrical polyamines was designed and synthesized as potential small molecule CXCR4 antagonists. Among them, a representative compound 21 (namely HF50731) showed strong CXCR4 binding affinity (mean IC50 = 19.8 nM) in the CXCR4 competitive binding assay. Furthermore, compound 21 significantly inhibited SDF-1α-induced calcium mobilization and cell migration, and blocked HIV-1 infection via antagonizing CXCR4 coreceptor function. The structure-activity relationship analysis, site-directed mutagenesis, and molecular docking were conducted to further elucidate the binding mode of compound 21, suggesting that compound 21 could primarily occupy the minor subpocket of CXCR4 and partially bind in the major subpocket by interacting with residues W94, D97, D171, and E288. Our studies provide not only new insights for the fragment-based design of small molecule CXCR4 antagonists for clinical applications, but also a new and effective molecular probe for CXCR4-targeting biological studies.

Hyperosmotic intraventricular drug delivery of DV1 in the management of intracranial metastatic breast cancer in a mouse model.

Advances in therapies for breast cancer with cerebral metastases has been slow, despite this being a common diagnosis, due to limited drug delivery by the blood brain barrier. Improvements in drug delivery for brain metastasis to target the metastases and bypass the blood brain barrier are necessary. In our study, we delivered an inhibitor of chemokine receptor 4 by convection enhanced delivery in a hyperosmotic solution to prevent brain metastasis in a mouse model of metastatic breast cancer. We found the inhibitor limited metastatic disease and more interestingly, the hyperosmotic solution targeted tumor tissue allowing for a higher accumulation of the therapy into tumor tissue. This finding has the potential to improve delivery of chemotherapeutic agents to brain metastases.

High affinity CXCR4 inhibitors generated by linking low affinity peptides.

G-protein coupled receptors (GPCRs) are implicated in many diseases and attractive targets for drug discovery. Peptide fragments derived from protein ligands of GPCRs are commonly used as probes of GPCR function and as leads for drug development. However, these peptide fragments lack the structural integrity of their parent full-length protein ligands and often show low receptor affinity, which limits their research and therapeutic values. It remains a challenge to efficiently generate high affinity peptide inhibitors of GPCRs. We have investigated a combinational approach involving the synthetic covalent linkage of two low affinity peptide fragments to determine if the strategy can yield high affinity GPCR inhibitors. We examined this design approach using the chemokine receptor CXCR4 as a model of GPCR system. Here, we provide a proof of concept demonstration by designing and synthesizing two peptides, AR5 and AR6, that combine a peptide fragment derived from two viral ligands of CXCR4, vMIP-II and HIV-1 envelope glycoprotein gp120. AR5 and AR6 display nanomolar binding affinity, in contrast to the weak micromolar CXCR4 binding of each peptide fragment alone, and inhibit HIV-1 entry via CXCR4. Further studies were carried out for the representative peptide AR6 using western blotting and site-directed mutagenesis in conjunction with molecular dynamic simulation and binding free energy calculation to determine how the peptide interacts with CXCR4 and inhibits its downstream signaling. These results demonstrate that this combinational approach is effective for generating nanomolar active inhibitors of CXCR4 and may be applicable to other GPCRs.

Molecular design and anticancer activities of small-molecule monopolar spindle 1 inhibitors: A Medicinal chemistry perspective.

As a dual-specificity protein kinase, monopolar spindle 1 (Mps1) is one of the main kinases involved in kinetochore localization and the spindle assembly checkpoint (SAC). Cancer cells often display chromosomal instability, which is a consequence of disfunction of cell cycle checkpoints partially. Mps1 is overexpressed in multiple cancer types to face the pressure from aberrant chromosomes and centrosomes. Therefore, Mps1 is a potential targeting approach to cancer treatment. Several compounds targeting Mps1 have been developed and approved to begin clinical trials for advanced nonhaematologic malignancies treatments, including but not limited to triple negative breast cancer (TNBC) treatment. In this review, we will highlight typical Mps1 inhibitors developed during the last decade and provide a reference for more potential Mps1 inhibitors exploration in the future.

Salidroside-regulated lipid metabolism with down-regulation of miR-370 in type 2 diabetic mice.

Salidroside is known for its pharmacological properties and in particular its antioxidation effects. In recent years, it has been recognized that salidroside plays an important role in treating diabetes. Accumulated evidence suggests that microRNAs may be involved in diabetic lipid disorders. We investigated how salidroside regulates lipid metabolism through miR-370 in vivo and in vitro. After 4 weeks of a high-fat diet, and intraperitoneal injection of streptozotocin (100mg/kg), type 2 diabetes was induced in male C56BL/6J mice. After 4 weeks, mice with fasting blood glucose levels above 7.8mmol/l were divided into five groups: those with diabetes mellitus, and those treated with 40mg/kg, 80mg/kg, and 160mg/kg salidroside, and metformin (480mg/kg), for a further 4 weeks. The hypoglycemic effects of salidroside were consistently demonstrated when measuring fasting blood glucose levels, observing insulin-sensitizing effects, and testing oral glucose tolerance. In addition to this, the expressions of miR-370, and related lipid protein expression in primary hepatocytes, were examined in primary type 2 diabetic mice. The present study has shown that the expression levels of miR-370, SREBP-1 and FAS-1 were significantly elevated in the liver of type 2 diabetic mice. In contrast, the elevated expression levels were reversed by salidroside. The addition of salidroside attenuated the effect of miR-370, and reduced the expression of these lipid metabolism proteins in primary hepatocytes. These findings demonstrate that salidroside can directly decrease the expression of miR-370 in type 2 diabetic mice, and particularly in primary hepatocytes, affecting lipid metabolism in the liver.