Synthesis of gold nanoparticles (Au@ligand) containing thiolic compounds as Ligand: applications to therapy and molecular imaging

Gold nanoparticles (AuNPs) are the most stable metal nanoparticles, completely biocompatible, which have already proved their excellent properties for production of nanostructured materials, biomolecule detection and biological diagnostics1. The use of AuNPs as biological probes requires the improvement of colloidal stability. Thiolated species, e.g. dihydrolipoic acid (DHLA) (1)- a dithiol obtained by the reduction of thioctic (or lipoic) acid (LA) (2) - significantly limit the aggregation and help to overcome the lack of stability of gold nanoparticle colloids, conclusion proved by the doubtless results of the sulfur K-edge XANES study2. The molecules of thio-acid form on the surface of gold nanoparticles a self-assembled monolayer (SAM) with enhanced order and hence, stability and with two points of attachement to gold- sulfur atoms2. Lately, in the field of nucleosides, nucleotides and oligonucleotides, sulfur chemistry assisted by AuNPs appears particularly fruitful in the development of therapeutic agents and tools for biology. For example, AuNPs ensure efficient, considerably enhanced delivery and intracellular uptake of the drug by cancer cells, compared to the same drug in typically administered free form. Enhanced activity and nanoparticle carriers make possible the reduction of the overall concentration of the drug, renal clearance, and thus, side effects. The nanoparticles with drug (mercaptopurine) also showed excellent stability over 1 year without loss of inhibitory activity 3. A synergistic effect was observed between AuNPs and the X-ray treatment resulting in tumor reduction or eradication4. Aim of the project / Experimental approach The aims of our project are: - to synthesize gold nanoparticles (Au@ligand) with ligands containing thiol function by the technique of SAM-s in the frame of collaboration with Prof. Francesca Porta and Dr. Zelijca Krptevic (Dipartimento di Chimica Inorganica Metallorganica Analitica-University of Milan; - to select different strategies related to the application of the prepared NP-s; - to test the synthesized gold nanoparticles (Au@ligand) on the in vitro activity in cell cultures or in vivo molecular imaging. Pursuing the identification of compounds endowed with in vitro and in vivo anticancer activity, we have selected a modified nucleoside N6-( 062-Isopentenyl)adenosine (IPA) as a drug to be delivered. As demonstrated by Spinola et al.5, IPA exerts a potent in vitro antitumoral activity on human epithelial cancer cell lines, but it is characterized by the lack of in vivo activity, that could be related to the short plasma half-life of IPA, as for other nucleosides. Following the observations of N.A.Kotov et al3, we suppose, that the conjugation of Au@thiolic ligand(LA or DHLA)-IPA would elevate plasma half-life of IPA. Thus, synthetic approach for obtaining of conjugates Au@thiolic ligand(LA or DHLA)-IPA has been built on the following: combination of LA with IPA, then -couple with Au-NP-s. For binding LA to IPA it was necessary to prepare an LA ester. Several trials have been done, with this target: 1. Lipoyl chloride, from LA and thionyl chloride \u2013 the polymerization of reaction product has been noticed; 2. Derivatives of LA: carbonate and mixed anhydride - reaction between LA and 1,1' \u2013carbonyldiimidazole; LA-imidazolide has been obtained as a stable product in good yield. - reaction with isopropylideneglycerol as model reaction; slow reaction and low yields of product - reaction with ethyl chlorocarbonate or ethyl chloroformate?; Mixed anhydride has been obtained as a stable product in acceptable yield 3. Synthesis of LA-trifluoroethyl ester for lipase-catalyzed acylation of a nucleoside (IPA) - Reaction of LA mixed anhydride and trifluoroethanol (TFE); TFE-ester of LA has been prepared in good yield, it is an activated one that improves yield of a lipase-catalyzed transesterification with acceptor R-OH. Further experimental investigations will be focused on the study of acilation reaction lipase-catalized, between TFE-ester of LA and IPA. It could be selective an afford only the targeted 5'-ester to be coupled to AuNP-s. References 1. M.-C.Daniel, D.Astruc. Chem. Rev. 2004, 104, 293-346. 2. B.Garsia, M. Salome, L.Lemelle, J.-L.Bridot, Ph.Gillet, P.Perriat, S.Roux, O.Tillement. Chem. Commun., 2005, 369-371. 3. P.Podsiadlo, V.A.Sinani, J.H.Bahng, N.W.S.Kam, J.Lee, N.A.Kotov. Langmuir, 2008, 24, 568-574. 4. Z. Krpetic, F.Porta, G.Scari. Gold Bull., 2006, 39(2), 66-68. 5 Spinola M., Colombo F., Falvella S., Dragani T. A. Int. J. Cancer, 2007; 120, 274

A reassessment of the role of sucrose synthase in the hypoxic sucrose‐ethanol transition in Arabidopsis

Plants under low-oxygen availability adapt their metabolism to compensate for the lower ATP production that arises from the limited respiratory activity in mitochondria. Anaerobic glycolysis requires continuous fuelling of carbon units, also provided from sucrose. The anaerobic catabolism of sucrose is thought to require the activity of sucrose synthase, being this enzymatic reaction more energetically favourable than that of invertase. The role of sucrose synthases (SUS) for aerobic sucrose catabolism in Arabidopsis has been recently questioned since SUS mutants fail to show altered phenotype or metabolic profile. In the present paper, we analysed the role of SUS1 and SUS4, both induced by low oxygen, in plant survival and ethanol production. The results showed that mutants lacking both SUS were as tolerant to low oxygen as the wild type in most of the experimental conditions tested. Only under conditions of limiting sugar availability the requirement of SUS1 and SUS4 for ethanol production was evident, although partly compensated by invertase activities, as revealed by the use of a double mutant lacking the two major cytosolic invertases. We conclude that, contrary to general belief, the sucrose synthase pathway is not the preferential route for sucrose metabolism under hypoxia

Synthesis of 2-substituted-6-hydroxy and 6-methoxy benzothiazoles from 1,4-benzoquinone

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Le Riparo Mochi (Balzi Rossi, Ventimiglia, Italie) : les nouvelles fouilles

Grimaldi Stefano, Santaniello Fabio, Starnini Elisabetta. Le Riparo Mochi (Balzi Rossi, Ventimiglia, Italie) : les nouvelles fouilles. In: Bulletin de la Société préhistorique française, tome 114, n°1, 2017. pp. 169-172

Antiproliferative activity of N 6-isopentenyladenosine on HCT-15 colon carcinoma cell line

N 6-Isopentenyladenosine (iPA), a member of the cytokinin family of plant hormones, exerts remarkable inhibition on tumor cell proliferation and apoptosis in several tumor cell lines. In this study, we report that iPA is able to inhibit the proliferation and promotes apoptosis in HCT-15 human colon cancer cells in a dose-dependent manner with a concentration of 2.5 \u3bcM, which causes 50% inhibition of cell viability. The cell cycle analysis by flow cytometry showed that iPA-induced growth arrest could be associated to apoptosis. Moreover, suppression of clonogenic activity occurs after exposure to iPA at a concentration of 2.5 \u3bcM for HCT-15

Microscopic Polyangiitis With Selective Involvement of Central and Peripheral Nervous System : A Case Report

Background: Microscopic polyangiitis (MPA) is a necrotizing vasculitis that affects predominantly small-sized vessels in many organ systems. The disease generally causes glomerulonephritis, pulmonary damage, arthritis, and neuropathy. An exclusive involvement of both central nervous system (CNS) and peripheral nervous system (PNS) is extremely rare. Case Presentation: A 62-year-old woman was admitted to our hospital with a 3 months history of right foot drop, recently complicated by intense myalgia, arthralgia, and allodynia to tactile, vibratory, and pressure stimuli. Since blood tests revealed elevated inflammatory indexes, we suspected either infectious or immune-mediated disorders. Chest radiograph, blood culture series, and echocardiogram revealed normal findings, while urinalysis showed a bacterial infection that was successfully treated. The neurophysiological findings were compatible with multiple mononeuritis, and a brain MRI evidenced ischemic lesions of both basal ganglia and thalamus. A wide-spectrum autoantibody assay revealed the presence of high-titer perinuclear anti-neutrophil cytoplasmic antibodies specific for myeloperoxidase (MPO-ANCA). According to these findings, the diagnosis of MPA was made, and the patient was successfully treated with intravenous (IV) methylprednisolone, followed by two doses of rituximab. Conclusions: An assessment of both CNS and PNS should be included in the diagnostic evaluation of MPA. The involvement of the PNS may raise the risk of a relapsing course and treatment failure, therefore it should be considered in the choice of induction and maintenance therapy

Fibroblast proliferation and migration in wound healing by phytochemicals: Evidence for a novel synergic outcome

Wound-healing is a dynamic skin reparative process that results in a sequence of events, including inflammation, proliferation, and migration of different cell types as fibroblasts. Fibroblasts play a crucial role in repairing processes, from the late inflammatory phase until the fully final epithelization of the injured tissue. Within this context, identifying tools able to implement cell proliferation and migration could improve tissue regeneration. Recently, plants species from all over the world are coming out as novel tools for therapeutic applications thanks to their phytochemicals, which have antioxidant properties and can promote wound healing. In this paper, we aimed at investigating antioxidant activity of waste extracts from different medicinal plants, endemic of the Mediterranean area, on fibroblast proliferation and wound healing. We determined the amount of total phenols and anti-oxidant activity by ABTS assay. We then evaluated the cytotoxicity of the compounds and the proliferative capabilities of fibroblasts by scratch assay. Our results showed that waste extracts retain antioxidant and regenerative properties, inducing tissue re-establishment after environmental stress exposure. Taken together, our findings suggest that waste material could be used in the future also in combinations to stimulate wound healing processes and antioxidant responses in damaged skin

Synthesis and characterization of 4-hydroxy-2-nonenal derivatives for gas chromatographic analysis with electron capture detection (GC-ECD)

4-Hydroxy-2-nonenal (HNE) has been prepared from the corresponding dimethylacetal (HNE-DMA), in turn synthesized by a conventional approach with a few modifications of the experimental protocol and some improvements in the purification of the final product. In order to exploit the sensitivity of gas-chromatography with electron capture detector (GC-ECD) in the analysis of HNE derivatives, reaction of HNE with 2,4,6-trichlophenylhydrazine (TCPH) and 3,5-dichlorophenylhydrazine (DCPH) was tested. Reaction with TCPH afforded a mixture of products, whereas with DCPH a single major product was formed that was prepared on a millimolar scale and purified. 1H-NMR analysis established that the derivative of HNE with DCPH is HNE 3,6-dichlorophenylhydrazone, that can be used as standard for GC-ECD analysis

Transcript profiling of chitosan-treated Arabidopsis seedlings

In nature, plants can recognize potential pathogens, thus activating intricate networks of defense signals and reactions. Inducible defense is often mediated by the detection of microbe or pathogen associated molecular pattern elicitors, such as flagellin and chitin. Chitosan, the deacetylated form of chitin, plays a role in inducing protection against pathogens in many plant species. We evaluated the ability of chitosan to confer resistance to Botrytis cinerea in Arabidopsis leaves. We subsequently treated Arabidopsis seedlings with chitosan and carried out a transcript profiling analysis using both ATH1 GeneChip microarrays and quantitative RT-PCR. The results showed that defense response genes, including camalexin biosynthesis genes, were up-regulated by chitosan, both in wild-type and in the chitin-insensitive cerk1 mutant, indicating that chitosan is perceived through a CERK1-independent pathway