Discovery of thiazolidin-4-one analogue as selective GSK-3ß inhibitor through structure based virtual screening.

GSK-3ß directly phosphorylate tubulin binding site of tau protein, indicating its importance in tau aggregation and, therefore, in Alzheimer's disease pathology. New GSK-3ß inhibitors were identified using a structure-based screening, ADMET analysis. These studies revealed that ZINC09036109, ZINC72371723, ZINC72371725, and ZINC01373165 approached optimal ADMET properties along with good MM-GBSA dG binding. Protein kinase assays of these compounds against eight disease-relevant kinases were performed. During disease-relevant kinase profiling, ZINC09036109 ((E)-2-((3,4-dimethylphenyl)imino)-5-(3-methoxy-4-(naphthalen-2-ylmethoxy)benzyl)thiazolidin-4-one) emerged as a selective GSK-3ß inhibitor with more than 10-fold selectivity over other disease-relevant kinases. Molecular dynamics study of ZINC09036109 molecule revealed interactions with Ile62, Phe67, Val135, Leu188, Asp200 amino acid residues of the binding site of GSK-3ß, which were highly comparable to the co-crystallized molecule and hence validating comparative better activity of this compound compared to overall screened molecules.

Betulin, a Newly Characterized Compound in Acacia auriculiformis Bark, Is a Multi-Target Protein Kinase Inhibitor.

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/ß (GSK-3 α/ß), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

The Anti-Candida albicans Agent 4-AN Inhibits Multiple Protein Kinases.

Small molecules containing quinone and/or oxime moieties have been found as promising anti-fungal agents. One of them is 4-AN, a recently reported potent anti-Candida compound, which inhibits the formation of hyphae, decreases the level of cellular phosphoproteome, and finally shows no toxicity towards human erythrocytes and zebrafish embryos. Here, further research on 4-AN is presented. The results revealed that the compound: (i) Kills Candida clinical isolates, including these with developed antibiotic resistance, (ii) affects mature biofilm, and (iii) moderately disrupts membrane permeability. Atomic force microscopy studies revealed a slight influence of 4-AN on the cell surface architecture. 4-AN was also shown to inhibit multiple various protein kinases, a characteristic shared by most of the ATP-competitive inhibitors. The presented compound can be used in novel strategies in the fight against candidiasis, and reversible protein phosphorylation should be taken into consideration as a target in designing these strategies.

Screening for Protein-Protein Interaction Inhibitors Using a Bioluminescence Resonance Energy Transfer (BRET)-Based Assay in Yeast.

The bioluminescence resonance energy transfer (BRET) technology is a widely used live cell-based method for monitoring protein-protein interactions as well as conformational changes within proteins or molecular complexes. Considering the emergence of protein-protein interactions as a new promising class of therapeutic targets, we have adapted the BRET method in budding yeast. In this technical note, we describe the advantages of using this simple eukaryotic model rather than mammalian cells to perform high-throughput screening of chemical compound collections: genetic tractability, tolerance to solvent, rapidity, and no need of expensive robotic systems. Here, the HDM2/p53 interaction, related to cancer, is used to highlight the interest of this technology in yeast. Sharing the protocol of this BRET-based assay with the scientific community will extend its application to other protein-protein interactions, even though it is toxic for mammalian cells, in order to discover promising therapeutic candidates.

[Screening marine resources to find novel chemical inhibitors of disease-relevant protein kinases]. / Le criblage à Roscoff - Une recherche d'inhibiteurs de kinases tournée vers la mer.

Since the early 1970's, investigators at Station Biologique de Roscoff (SBR), France, have been using marine organisms as models to describe molecular pathways conserved through evolution in mammalian cells (e.g. the cyclin-dependent kinases involved in the control of the cell division cycle). Some kinases are misregulated in various human pathologies, including cancers. Using a specialized screening approach, chemical libraries were analysed, using on-site facilities at Roscoff, in order to identify small chemical inhibitors of protein kinases. Eight chemical scaffolds produced by marine organisms were characterized as candidate drugs by our screening facility, some of which are being considered as chemical tools to pinpoint specific cellular functions of the targeted kinases. In this review, we describe our existing screening facilities and we discuss new perspectives related to marine bioprospecting.

A yeast-based assay to isolate drugs active against mammalian prions.

Recently, we have developed a yeast-based (Saccharomyces cerevisiae) assay to isolate drugs active against mammalian prions. The initial assumption was that mechanisms controlling prion appearance and/or propagation could be conserved from yeast to human, as it is the case for most of the major cell biology regulatory mechanisms. Indeed, the vast majority of drugs we isolated as active against both [PSI(+)] and [URE3] budding yeast prions turned out to be also active against mammalian prion in three different mammalian cell-based assays. These results strongly argue in favor of common prion controlling mechanisms conserved in eukaryotes, thus validating our yeast-based assay and also the use of budding yeast to identify antiprion compounds and to study the prion world.