Integrin-mediated human glioblastoma cells adhesion, migration and invasion by native and recombinant phospholipases of Scorpio maurus venom glands

International audienceIntegrins are a large family of cell surface receptors mediating the interaction of cells with their microenvironment and they play an important role in glioma biology. In the present work, we reported the anti-tumor effect of Sm-PLGV a phospholipase A2 from Tunisian scorpion venom glands-as well as its recombinant forms expressed in Escherichia coli-through interference with integrin receptor function in malignant glioma cells U87. These phospholipases inhibited in a dose dependent manner the adhesion, migration and invasion onto fibrinogen and fibronectin without any cytotoxicity. We showed that Sm-PLGV and its recombinant constructs blocked U87 migration by reducing their velocity and directional persistence. The inhibitory effect was related to a blockage of the integrins αvβ3 and α5β1 function. Inactivation of the enzymatic activity of Sm-PLGV by chemical modification with p-bromophenacyl bromide did not affect its anti-tumor properties, suggesting the presence of 'pharmacological sites' distinct from the catalytic site in scorpion venom phospholipases A2

Lamellar and Supramolecular Feature of New Tutton's Salts Incorporating 2-Amino-4-Methylpyrimidine: Thermal Stability, Optic Study, Antioxidant and Antimicrobial Activities

International audienceThe slow evaporation reaction of 2-amino-4-methylpyrimidine and transition metal cation (M-II = Fe and Ni) in the presence of sulfuric acid H2SO4 affords two novel double sulfate salts with similar general formula (C5H8N3)(2)[M-II(H2O)(6)](SO4)(2)center dot 2H(2)O (M-II = Fe and Ni) abbreviated FePRM and NiPRM, respectively. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by Infra-Red (IR) spectra, thermogravimetric analysis-differential scanning calorimetry (TG-DSC) and variable temperature powder X-ray diffraction (VT-PXRD) measurements. Structural characterization shows that the interplay of N-H center dot center dot center dot O, O-H center dot center dot center dot O and pi center dot center dot center dot pi interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three dimensional supramolecular assembly. Then, the structure exhibits lamellar topology where the interlayer distances are 13.065(4) and 13.138 (5) angstrom for FePRM and NiPRM, respectively. Hirshfeld surface analysis employing 3D molecular surface contours and 2D fingerprint plots have been used to analyze the intermolecular interactions present in the crystals. The optical properties were characterized by UV-visible spectroscopy and the calculated band gap was estimated to be 3.91 and 4.08 eV for FePRM and NiPRM, respectively. In addition, the biological activities of the complexes were investigated through the scavenging effect on DPPH radicals, reducing and phosphonolybdonum assay as antioxidant activities

Native and recombinant phospholipases A2 of Scorpio maurus venom glands impair angiogenesis by targeting integrins α5β1 and αvβ3.

International audienceWe recently purified an heterodimeric phospholipase A2 named Sm-PLGV from the venom glands of scorpion Scorpio maurus containing a Long chain, a penta-peptide insertion, which is cut out during the maturation, followed by a short chain. Three recombinant forms of Sm-PLGV were produced in Escherichia coli: rPLA2(+5) containing the full-length sequence including the penta-peptide insert, rPLA2(-5) a fused continuous chain of the Long and the short chains without the penta-peptide and the Long chain alone without the short one. In this study, we showed that Sm-PLGV, rPLA2(+5) and rPLA2(-5) displayed more potent anti-angiogenic properties than the recombinant Long chain and the short chain obtained by chemical synthesis. These phospholipases A2 inhibited in a dose-dependent manner adhesion, migration and invasion of human microvascular endothelial cells through the alteration of α5β1 and αvβ3 integrins function. Using Matrigel™ and chick chorioallantoic membrane assays, we demonstrated that Sm-PLGV, rPLA2(+5) and rPLA2(-5) significantly inhibited both in vitro and in vivo angiogenesis. We also showed a clear dissociation of the anti-angiogenic effect of Sm-PLGV and its catalytic activity. This is the first study describing an anti-angiogenic effect for recombinant scorpion venom enzymes

Anti-angiogenic effect of phospholipases A 2 from Scorpio maurus venom glands on Human Umbilical Vein Endothelial Cells

International audienceIn a previous study, we purified Sm-PLGV an heterodimeric phospholipase A2, from the venom glands of the Tunisian scorpion Scorpio maurus. This enzyme contains a Long chain, a penta-peptide insertion, which is cut out during the maturation process, followed by a short chain. A disulfide bridge links the two chains. Three recombinant forms of this enzyme were produced in Escherichia coli: rPLA2(+5) with a penta-peptide insert, rPLA2(-5) without the penta-peptide, and the Long chain alone without the short one. In the present study, we showed that Sm-PLGV, rPLA2(+5) and rPLA2(-5) displayed more potent anti-angiogenic activity in vitro than the recombinant Long chain and the short one obtained by chemical synthesis. These phospholipases A2 inhibited in a dose-dependent manner adhesion, migration and invasion of Human Umbilical Vein Endothelial Cells. Using Matrigel™, we demonstrated that Sm-PLGV, rPLA2(+5) and rPLA2(-5) significantly inhibited tubulogensesis. We also showed a clear dissociation between the anti-angiogenic effect of Sm-PLGV and its catalytic activity

Functional characterization and FTIR-based 3D modeling of full length and truncated forms of Scorpio maurus venom phospholipase A 2

International audienceBackground: Heterodimeric phospholipase A2 from venom glands of Tunisian scorpion Scorpio maurus (Sm-PLGV) had been purified. It contains long and short chains linked by a disulfide bridge. Sm-PLGV exhibits hemolytic activity towards human erythrocytes and interacts with phospholipid monolayers at high surface pressure. The investigation of structure-function relationships should provide new clues to understand its activity.Methods: Molecular cloning of Sm-PLGV and heterologous expression in Escherichia coli of three recombinant forms was used to determine the role of the short chain on enzymatic activity. Infrared spectroscopy assisted 3D model building of the three recombinant constructs (phospholipases with and without the penta-peptide and Long chain only) allowed us to propose an explanation of the differences in specific activities and their interaction with various phospholipids.Results: Nucleotide sequence of Sm-PLGV encodes 129 residues corresponding to the Long chain, the penta-peptide and the short chain. Although recombinant phospholipases without and with the penta-peptide have different specific activities, they display a similar substrate specificity on various phospholipid monolayers and similar bell-shaped activity profiles with maxima at high surface pressure. The absence of the short chain reduces significantly enzymatic and hemolytic activities. The 3D models pointed to an interaction of the short chain with the catalytic residues, what might explain the difference in activities of our constructs.Conclusion: Infrared spectroscopy data and 3D modeling confirm the experimental findings that highlight the importance of the short chain for the Sm-PLGV activity

The effect of partial substitution of chloride by bromide in the 0-D hybrid material (C4H12N2)[CuCl4]center dot 2H(2)O: Structural, vibrational, thermal, in silico and biological characterizations

International audienceA new organic-inorganic hybrid material with copper(II) as the transition metal, piperazine as the organic component and mixed bromide/chloride as halide ions, (C4H12N2)[CuBr4](0.42)[CuCl4](0.58)center dot 2H(2)O (1), has been prepared and crystallographically investigated by single-crystal X-ray diffraction. Unlike the parent chloride or bromide-based materials which adopt the monoclinic system, this mixed halide hybrid material crystallizes in the space group Pnma of the orthorhombic system with the following parameters: a = 12.3496(6) angstrom, b = 16.3147(11) angstrom, c = 6.4415(3) angstrom, V = 1397.83(12) angstrom(3) and Z = 4. Its 0-D crystal packing is built of isolated entities, a copper(II) ion surrounded by four chloride/bromide ions [CuBr4](2-) and [CuCl4](2-), a diprotonated diamine (C4H12N2)(2+) and free water molecules. Additionally, these entities are linked through different types of intermolecular hydrogen bonds N-H horizontal ellipsis Br, N-H horizontal ellipsis Cl, N-H horizontal ellipsis Ow, Ow-H horizontal ellipsis Br, Ow-H horizontal ellipsis Cl, and weak non-covalent interactions C-H horizontal ellipsis Br and C-H horizontal ellipsis Cl [Ow = water oxygen]. The thermal decomposition of the precursor proceeds through four stages leading to copper(II) oxide as a final product. The title compound possesses antimicrobial and anti-tumoral effects comparable to two previously described compounds, as assessed by in silico examinations. Compound 1 inhibited in a dose dependent manner, the proliferation of gram negative and positive bacteria and exhibited a microbial lipase inhibition from Candida rugosa

Functional Characterization and Anti-Tumor Effect of a Novel Group II Secreted Phospholipase A₂ from Snake Venom of Saudi <i>Cerastes cerates gasperetti</i>

Secreted phospholipases A2 are snake-venom proteins with many biological activities, notably anti-tumor activity. Phospholipases from the same snake type but different geographical locations have shown similar biochemical and biological activities with minor differences in protein sequences. Thus, the discovery of a new phospholipase A2 with unique characteristics identified in a previously studied venom could suggest the origins of these differences. Here, a new Group II secreted phospholipase A2 (Cc-PLA2-II) from the snake venom of Saudi Cerastes cerastes gasperetti was isolated and characterized. The purified enzyme had a molecular weight of 13.945 kDa and showed high specific activity on emulsified phosphatidylcholine of 1560 U/mg at pH 9.5 and 50 °C with strict calcium dependence. Interestingly, stability in extreme pH and high temperatures was observed after enzyme incubation at several pH levels and temperatures. Moreover, a significant dose-dependent cytotoxic anti-tumor effect against six human cancer cell lines was observed with concentrations of Cc-PLA2 ranging from 2.5 to 8 µM. No cytotoxic effect on normal human umbilical-vein endothelial cells was noted. These results suggest that Cc-PLA2-II potentially has angiogenic activity of besides cytotoxicity as part of its anti-tumor mechanism. This study justifies the inclusion of this enzyme in many applications for anticancer drug development

Organic–Inorganic Manganese (II) Halide Hybrid Combining the Two Isomers Cis/Trans of [MnCl₄(H₂O)₂]: Crystal Structure, Physical Properties, Pharmacokinetics and Biological Evaluation

A manganese (II) complex templated by hexahydro-1,4-diazepinediium as a counter ion was grown by slow evaporation from an aqueous solution at room temperature. The X-ray diffraction analysis revealed that the compound (C5H14N2)[MnCl4(H2O)2] crystallizes in the centrosymmetric space group P2/c of the monoclinic system. The crystal structure of the Mn(II) complex is characterized by an alternation of 0-dimensional organic and inorganic stacks linked together by N/O-H…Cl and N-H…O hydrogen bonds, which lead to a three-dimensional supramolecular architecture. In this structure, the inorganic layer is built up by independent anionic moieties combining the two isomers cis/trans of [MnCl4(H2O)2]2−. The thermal decomposition was studied by TGA-DTA techniques. The optical band gap and Urbach energy were obtained by Tauc’s equation. The direct and indirect band gap values are found to be 4.58 and 4.44 eV, respectively. Weak antiferromagnetic interactions are present in the molecule under study, according to magnetic measurements. An agar well diffusion technique was used to assess the synthetic compound’s biological activity, and the results showed that it has potent antibacterial (Gram-positive and Gram-negative) properties. Interestingly, the synthesized compound also displayed antilipase activity. These biological activities have been confirmed by the bioavailability and pharmacokinetic analyses

Organic&ndash;Inorganic Manganese (II) Halide Hybrid Combining the Two Isomers Cis/Trans of [MnCl4(H2O)2]: Crystal Structure, Physical Properties, Pharmacokinetics and Biological Evaluation

A manganese (II) complex templated by hexahydro-1,4-diazepinediium as a counter ion was grown by slow evaporation from an aqueous solution at room temperature. The X-ray diffraction analysis revealed that the compound (C5H14N2)[MnCl4(H2O)2] crystallizes in the centrosymmetric space group P2/c of the monoclinic system. The crystal structure of the Mn(II) complex is characterized by an alternation of 0-dimensional organic and inorganic stacks linked together by N/O-H&hellip;Cl and N-H&hellip;O hydrogen bonds, which lead to a three-dimensional supramolecular architecture. In this structure, the inorganic layer is built up by independent anionic moieties combining the two isomers cis/trans of [MnCl4(H2O)2]2&minus;. The thermal decomposition was studied by TGA-DTA techniques. The optical band gap and Urbach energy were obtained by Tauc&rsquo;s equation. The direct and indirect band gap values are found to be 4.58 and 4.44 eV, respectively. Weak antiferromagnetic interactions are present in the molecule under study, according to magnetic measurements. An agar well diffusion technique was used to assess the synthetic compound&rsquo;s biological activity, and the results showed that it has potent antibacterial (Gram-positive and Gram-negative) properties. Interestingly, the synthesized compound also displayed antilipase activity. These biological activities have been confirmed by the bioavailability and pharmacokinetic analyses