Ines Bruno

Structure-Based Discovery of Inhibitors of Microsomal Prostaglandin E2 Synthase−1, 5-Lipoxygenase and 5-Lipoxygenase-Activating Protein: Promising Hits for the Development of New Anti-inflammatory Agents

Microsomal prostaglandin E(2) synthase (mPGES)-1 catalyzes the transformation of PGH(2) to PGE(2) that is involved in several pathologies like fever, pain, and inflammatory disorders. To identify novel mPGES-1 inhibitors, we used in silico screening to rapidly direct the synthesis, based on the copper-catalyzed 3 + 2 Huisgens reaction (click chemistry), of potential inhibitors. We designed 26 new triazole-based compounds in accordance with the pocket binding requirements of human mPGES-1. Docking results, in agreement with ligand efficiency values, suggested the synthesis of 15 compounds that at least in theory were shown to be more efficient in inhibiting mPGES-1. Biological evaluation of these selected compounds has disclosed three new potential anti-inflammatory drugs: (I) compound 4 displaying selectivity for mPGES-1 with an IC(50) value of 3.2 μM, (II) compound 20 that dually inhibits 5-lipoxygenase and mPGES-1, and (III) compound 7 apparently acting as 5-lipoxygenase-activating protein inhibitor (IC(50) = 0.4 μM).

Two new guanidine alkaloids from the Mediterranean sponge Crambe crambe

Crambine A (1) and B (2) were isolated from the Mediterranean sponge Crambe crambe. Their structures were determined mainly by extensive NMR 2D experiments at 600 MHz.

Dactylolide, a New Cytotoxic Macrolide from the Vanuatu SpongeDactylospongia sp.

Dactylolide (1), a new cytotoxic 20-membered macrolide, was isolated from a marine sponge of the genus Dactylospongia collected off the coast of the Vanuatu islands. It co-occurred with other known bioactive macrolides: latrunculin A (2), laulimalide (3), isolaulimalide (4) and with the anthelminthic mycothiazole (5). The structure of 1, which is a minor metabolite, was elucidated by spectroscopy (mainly by 1D/2D NMR and MS techniques). It showed cytotoxic activity against the L1210 and SK-OV-3 tumor cell lines (63% and 40% inhibition at 3.2 μg/mL).

Chemistry and biology of chromatin remodeling agents: state of art and future perspectives of HDAC inhibitors.

Chromatin remodeling is a fundamental phenomenon in the life of eukaryotic cells, bearing implications to numerous physiological and pathological phenomena. This review outlines the chemistry of natural and synthetic agents endowed with the ability to interfere with such biological function, with a particular emphasis on histone deacetylase (HDAC) inhibitors. Other aspects covered in this article comprise structure activity relationships (SAR) and modes of action at molecular level, including the description of crystal structures of enzyme-inhibitor complexes.

Crambines C1 and C2 : two further ichthyotoxic guanidine alkaloids from the sponge Crambe crambe

Recently we reported the isolation and structure determination of two ichthyotoxic guanidine compounds, crambines A 111 and B 121, from a specimen of the encrusting Mediterranean sponge Crambe crambe Schmidt (Poecilosclerida; Crambidae) collected near Banyuls, France (1). The toxic n-BuOH extract from which these two compounds were isolated is a complex mixture. After repetitive chromatographies on Sephadex LH 20, Si gel, and polyvinylpolypyrrolidone, a further toxic Sakaguchi-positive fraction homogeneous by tlc could be isolated. This fraction contained a new guanidine alkaloid, crambine C1 131, accompanied by a series of homologues of 3 where n = 8, 10, and 11. The same compound was also isolated as a minor component from specimens of C. cram& collected off Favignana, Italy together with crambine A (major), crambine B, and a further minor compound, crambine C2 [4]. Crambine C1 was also isolated from a specimen of C. crambe collected near Nice, France, but in this last sample, crambine C1 was, together with crambine A, one of the major compounds of the toxic extract. Crambine C1 131 displayed an [M + HI+ ion at d z 48 1.390 in positive hrfabms, which corresponds to the molecular formula CZSH48N@3 for the corresponding free base. This molecular formula was further confirmed by negative fabms which exhibits peaks at d z 479 [M wand 5 15 [M H +Ha]-. These fab mass spectra also showed peaks

Effects of FR235222, a novel HDAC inhibitor, in proliferation and apoptosis of human leukaemia cell lines: Role of Annexin A1

FR235222, a novel histone deacetylase inhibitor (HDACi), at 50nM caused accumulation of acetylated histone H4, inhibition of cell proliferation and G1 cycle arrest accompanied by increase of p21 and down-regulation of cyclin E in human promyelocytic leukaemia U937 cells. The compound was also able to increase the protein and mRNA levels of annexin A1 (ANXA1) without effects on apoptosis. Similar effects were observed in human chronic myelogenous leukaemia K562 cells and human T cell leukaemia Jurkat cells. Cycle arrest and ANXA1 expression, without significant effects on apoptosis, were also induced by different HDACi like suberoylanilide hydroxamic acid (SAHA) and trichostatin-A (TSA). FR235222 at 0.5 microM stimulated apoptosis of all leukaemia cell lines associated to an increased expression of the full-length (37kDa) protein and the appearance of a 33kDa N-terminal cleavage product in both cytosol and membrane. These results suggest that ANXA1 expression may mediate cycle arrest induced by low doses FR235222, whereas apoptosis induced by high doses FR235222 is associated to ANXA1 processing.

9H-purine scaffold reveals induced-fit pocket plasticity of the BRD9 bromodomain

The 2-amine-9H-purine scaffold was identified as a weak bromodomain template and was developed via iterative structure based design into a potent nanomolar ligand for the bromodomain of human BRD9 with small residual micromolar affinity toward the bromodomain of BRD4. Binding of the lead compound 11 to the bromodomain of BRD9 results in an unprecedented rearrangement of residues forming the acetyllysine recognition site, affecting plasticity of the protein in an induced-fit pocket. The compound does not exhibit any cytotoxic effect in HEK293 cells and displaces the BRD9 bromodomain from chromatin in bioluminescence proximity assays without affecting the BRD4/histone complex. The 2-amine-9H-purine scaffold represents a novel template that can be further modified to yield highly potent and selective tool compounds to interrogate the biological role of BRD9 in diverse cellular systems.

Spongidepsin, a new cytotoxic macrolide from Spongia sp.

Abstract A novel macrolide, spongidepsin ( 1 ) has been isolated from the Vanuatu marine sponge Spongia sp. The structure of 1 , which contains 9-hydroxy-2,4,7-trimethyltetradeca-14-ynoic acid and N -methylphenylalanine residues joined in a 13-membered ring, was elucidated by spectroscopic analysis. Spongidepsin ( 1 ) showed cytotoxic activity against J774.A1, WEHI-164 and HEK-293 cancer cell lines with an IC 50 in the sub-micromolar range.

Design and synthesis of a second series of triazole-based compounds as potent dual mPGES-1 and 5-lipoxygenase inhibitors.

Microsomal prostaglandin E(2) synthase (mPGES)-1 and 5-lipoxygenase (5-LO) are pivotal enzymes in the biosynthesis of the pro-inflammatory PGE(2) and leukotrienes, respectively. The design and synthesis of a second series of mPGES-1 inhibitors based on a triazole scaffold are described. Our studies allowed us to draw a tentative SAR profile and to optimize this series with the identification of compounds 10, 11 and 14-15 which displayed potent mPGES-1 inhibition in a cell-free assay. In addition, compounds 5, 10, 12 and 14-16 also blocked 5-LO activity in cell-free and cell-based test systems, emerging as very promising candidates for the development of safer and more effective anti-inflammatory drugs.

Structural basis for the design and synthesis of selective HDAC inhibitors

Histone Deacetylases are considered promising targets for cancer epigenetic therapy, and small molecules able to modulate their biological function have recently gained an increasing interest as potential anticancer agents. In spite of their potential application in cancer therapy, most HDAC inhibitors unselectively bind the several HDAC isoforms, giving rise to different side-effects. In this context, we have traced out the structural elements responsible of selective binding for the therapeutically relevant different HDAC isoforms. The structural analysis has been carried out by molecular modeling, docking in the binding pockets of HDAC1-4 and HDAC6-8, 36 inhibitors presenting a well defined selectivity for the different isoforms. As quick proof of evidence, we have designed, synthesized and experimentally tested three selective ligands. The experimental data suggest that the obtained structural guidelines can be useful tools for the rational design of new potent inhibitors against selected HDAC isoforms.