Patricia Melnyk

University of Lille Nord de France, Lille, Nord-Pas-de-Calais, France

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Publications (31)77.63 Total impact

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    ABSTRACT: The capacity of many proteins to interact with natural or synthetic polyanions has been exploited for modulating their biological action. However, the polydispersity of these macromolecular polyanions as well as their poor specificity is a severe limitation to their use as drugs. An emerging trend in this field is the synthesis of homogeneous and well-defined polyanion-peptide conjugates which act as bivalent ligands with the peptide part bringing the selectivity of the scaffold. Alternately, this strategy can be used for improving the binding of short peptides to polyanion-binding protein targets. This work describes the design and first synthesis of homogeneous polysulfonate-peptide conjugates using thiocarbamate ligation for binding to the extracellular domain of MET tyrosine kinase receptor for hepatocyte growth factor.
    Bioconjugate Chemistry 04/2014; · 4.58 Impact Factor
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    ABSTRACT: The design of novel chemoselective and site-specific ligation methods provides new tools for obtaining complex scaffolds, peptidomimetics and peptide conjugates. The chemistry of the N-phenylthiocarbonyl group has led to several developments in peptide ligation chemistry and peptide bioconjugation during the last ten years. The aim of this review is to provide an overview of this emerging field.
    Bioconjugate Chemistry 03/2014; · 4.58 Impact Factor
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    ABSTRACT: Lipid lowering agent such as agonists of peroxisome proliferator-activated receptors (PPAR) are suggested as neuroprotective agents and may protect from the sequelae of brain ischemic stroke. Although the demonstration is not clearly established in human, the underlying molecular mechanism may be of interest for future therapeutic purposes. To this end, we have used our well established rodent model of ischemia-reperfusion pre-treated or not with fenofibrate or atorvastatin and performed a differential proteomics analyses of the brain and analysed the protein markers which levels returned to "normal" following pre-treatments with PPARα agonists.
    Proteome Science 01/2014; 12:24. · 2.42 Impact Factor
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    ABSTRACT: Heparanase is a key enzyme involved in the dissemination of metastatic cancer cells. In this study a combination of in silico techniques and experimental methods was used to identify new potential inhibitors against this target. A 3D model of heparanase was built from sequence homology and applied to the virtual screening of a library composed of 27 known heparanase inhibitors and a commercial collection of drugs and drug-like compounds. The docking results from this campaign were combined with those obtained from a pharmacophore model recently published based in the same set of chemicals. Compounds were then ranked according to their theoretical binding affinity, and the top-rated commercial drugs were selected for further experimental evaluation. Biophysical methods (NMR and SPR) were applied to assess experimentally the interaction of the selected compounds with heparanase. The binding site was evaluated via competition experiments, using a known inhibitor of heparanase. Three of the selected drugs were found to bind to the active site of the protein and their K(D) values were determined. Among them, the antimalarial drug amodiaquine presented affinity towards the protein in the low-micromolar range, and was singled out for a SAR study based on its chemical scaffold. A subset of fourteen 4-arylaminoquinolines from a global set of 249 analogues of amodiaquine was selected based on the application of in silico models, a QSAR solubility prediction model and a chemical diversity analysis. Some of these compounds displayed binding affinities in the micromolar range.
    Bioorganic & medicinal chemistry 01/2013; · 2.82 Impact Factor
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    ABSTRACT: Title compounds (VI) are synthesized starting from amine (I) and aldehyde (II) using Bischler—Napieralski or Pictet—Spengler reactions as key reactions.
    ChemInform 01/2013; 44(2).
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    ABSTRACT: A prerequisite to dephosphorylation at Ser-Pro or Thr-Pro motifs is the isomerization of the imidic peptide bond preceding the proline. The peptidyl-prolyl cis/trans isomerase named Pin1 catalyzes this mechanism. Through isomerization, Pin1 regulates the function of a growing number of targets including the microtubule-associated tau protein and is supposed to be deregulated Alzheimer's disease (AD). Using proteomics, we showed that Pin1 is posttranslationally modified on more than 5 residues, comprising phosphorylation, N-acetylation, and oxidation. Although Pin1 expression remained constant, Pin1 posttranslational two-dimensional pattern was modified by tau overexpression in a tau-inducible neuroblastoma cell line, in our THY-Tau22 mouse model of tauopathy as well as in AD. Interestingly, in all of these systems, Pin1 modifications were very similar. In AD brain tissue when compared with control, Pin1 is hyperphosphorylated at serine 16 and found in the most insoluble hyperphosphorylated tau fraction of AD brain tissue. Furthermore, in all tau pathology conditions, acetylation of Pin1 may also contribute to the differences observed. In conclusion, Pin1 displays several posttranslational modifications, which are specific in tauopathies and may be useful as biomarker.
    Neurobiology of aging 08/2012; · 5.94 Impact Factor
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    ABSTRACT: Amodiaquine is one of the most active anti-malarial 4-aminoquinoline but its metabolization is believed to generate hepatotoxic derivatives. Previously, we described new analogs of amodiaquine and amopyroquine, in which hydroxyl group was replaced by various amino groups and identified highly potent compounds with lower toxicity. We describe here the synthesis of new analogs that have been modified on their 4'- and 5'-positions in order to reduce their metabolization. A new synthetic strategy was developed using Buchwald coupling reaction as the key step.
    European journal of medicinal chemistry 07/2011; 46(7):3052-7. · 3.27 Impact Factor
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    ABSTRACT: The configurational stability of seven Tic-hydantoin sigma-1 agonists 1–7 was studied in organic and aqueous media to mimic conditions encountered during either their synthesis or their evaluation as a drug candidate (physico chemical property determination and pharmacological study). This study was performed from the enantiomers directly obtained by asymmetric synthesis (hydantoins 1, 3–7) or after semi-preparative separation of the racemic obtained according to the same asymmetric procedure (thiohydantoin 2), by chiral HPLC. The racemization phenomenon was followed using recently validated chiral HPLC and capillary electrophoresis separation methods using derivatized cellulose and amylose chiral stationary phases (Chiralcel OD-H and Chiralpak AD) and highly sulphated cyclodextrins [highly S-β-CD in the background electrolyte (BGE)], respectively. The kinetic parameters (rate constant, half-life and apparent free energy barriers) of racemization were calculated using a first-order reaction model. The influence of the acid–base content, pH in aqueous medium, concentration of the buffer, and temperature were investigated. The fastest racemization rates were observed under basic conditions. All hydantoins were shown to present the same magnitude of configurational stability, whereas thiohydantoin 2 was characterized by a high chiral instability, especially in ethanolic and aqueous media: its high instability in ethanol explains that a racemic mixture was obtained after asymmetric synthesis; its instantaneous racemization observed from the neutral pH makes the preparation of the enantiomers of 2 not relevant. Finally, the mechanism of racemization was elucidated using nuclear magnetic resonance (NMR): the comparison of the kinetics of the deuteration to the kinetics of the racemization suggests the involvement of a common reaction mechanism of SE1 type for hydantoin 1, while an SE2 type reaction seems to be involved for thiohydantoin 2.
    Tetrahedron Asymmetry 01/2011; 22(2):125-133. · 2.12 Impact Factor
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    ABSTRACT: Activation of the newly identified σ₁ chaperone protein is involved in several aspects of the psychostimulant and addictive effects of cocaine. The development of ligands that selectively target the σ₁ protein may lead to putative potent anti-cocaine agents. We report here a new and more convergent synthetic pathway to amino side chain substituted hydantoins. Twenty new analogs of our lead compound were synthesized. None of them showed better in vitro affinity for σ₁ receptor than our lead compound. Nevertheless, three of them, obtained as racemates, showed high in vitro affinity and selectivity for σ₁ receptor. A preliminary in vivo evaluation of their pharmacological activity identified compound 22 as one that increases cocaine-induced locomotor stimulation and therefore acts as a potential efficient σ₁ agonist.
    Medicinal chemistry (Shāriqah (United Arab Emirates)) 11/2010; 6(6):355-73. · 1.64 Impact Factor
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    ABSTRACT: Stereospecific separations of seven Tic-hydantoin sigma-1 agonists were performed by both HPLC method using derivatized cellulose and amylose chiral stationary phases and capillary electrophoresis (CE) method using neutral and anionic cyclodextrins added in the background electrolyte (BGE). An optimal baseline separation (R(s)>3.3 with analysis times<25min) was readily obtained with all silica-based celluloses and amyloses using a normal-phase methodology. CE was used as an alternative technique to HPLC for the Tic-hydantoin derivatives separation. The enantiomers were fully resolved with highly sulfated beta-cyclodextrins at pH 2.5 (R(s)>1.5 with analysis times <11min). Both methods were validated in terms of linearity, detection and quantification limits. They were used to check the enantiomeric purity of the enantiomers.
    Journal of Chromatography A 06/2010; 1217(24):3871-5. · 4.61 Impact Factor
  • ChemInform 01/2010; 41(19).
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    ABSTRACT: Sigma-1 receptors are involved in numerous pathological dysfunctions and the synthesis of selective ligands is of interest. We identified a fused tetrahydroisoquinoline-hydantoin (Tic-hydantoin) structure with high affinity and selectivity for these receptors. We report here our efforts towards the pharmacomodulation of this substructure, the synthesis of 9 analogs with stereochemistry inversion, opening of isoquinoline ring, removal of isoquinoline nitrogen, replacement of isoquinoline by pyridine, of Tic-hydantoin moiety by quinazolinedione heterocycle. All these analogs provided a loss in the affinity for the sigma-1 receptor. The present work underlines the real importance of the Tic-hydantoin moiety for the obtainment of high affinity ligands.
    European journal of medicinal chemistry 10/2009; 45(1):256-63. · 3.27 Impact Factor
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    ABSTRACT: The purpose of this study was to design and characterize two flavonoid-loaded lipid nanocapsules (LNC) by applying the phase inversion process, and to enhance their apparent solubility and/or the stability. The flavonoid-loaded LNC were characterized by particle size, encapsulation efficiency, drug leakage rates, stability and spectroscopic studies. It was observed that quercetin-loaded LNC30 (3%) and LNC60 (2%) carried a particle size of 30.3 and 55.1 nm, respectively and significant higher entrapment efficiency. Encapsulation of quercetin (QC) in LNC enabled us to increase its apparent aqueous solubility by a factor of 100. And in view of calculations and results, it seems most probable that QC is arranged at this LNC interface between the oil phase and the hydrophilic polyethylene glycol moieties of the surfactant. In addition, colloidal suspensions proved to be stable in term of encapsulation for at least 10 weeks and QC was not oxidised. With simple chemical modification of (-)-epigallocatechin-3-gallate or (-)-EGCG, it was possible to reach very high encapsulation rates (95%). Thus we obtained stable colloidal suspensions of (-)-EGCG in water over 4 weeks while free (-)-EGCG solubilised in water exhibited 100% degradation within 4h. The initial problems (solubility and stability) of these flavonoids were resolved thanks to drug-loaded LNC.
    International Journal of Pharmaceutics 07/2009; 379(2):270-7. · 3.99 Impact Factor
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    ABSTRACT: The prophylactic administration of amodiaquine (AQ), a 4-aminoquinoline antimalarial drug, has been associated with side effects such as agranulocytosis and liver damage. The toxicity of this drug is mediated by amodiaquine quinone-imine, an electrophilic metabolite. Replacement of the 4'-hydroxy function of AQ with various alkyl, aryl, or heteroaryl substituents would provide analogues that avoid metabolism to potentially toxic derivatives. Following a multistep procedure, 33 compounds containing hydrophobic groups at the 4'-position were synthesized using Csp(2)-Csp(2) and Csp(2)-Csp(3) Suzuki-Miyaura cross-coupling reactions as the key step. The new derivatives were found to be active against both chloroquine (CQ)-sensitive and CQ-resistant strains of P. falciparum, with IC(50) values in the range of 7-200 nM. Alkyl analogues are more efficient than aryl or heteroaryl derivatives. All compounds were also assessed for their cytotoxicity and ability to inhibit beta-hematin formation in vitro. A detailed investigation of the structure-activity relationships for these new compounds was carried out; the 4'-methyl compound showed interesting in vivo antimalarial activity.
    ChemMedChem 03/2009; 4(4):549-61. · 2.84 Impact Factor
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    ABSTRACT: Activation of the newly identified sigma(1) chaperone protein is involved in several aspects of the psychostimulant and addictive effects of cocaine. The development of ligands that selectively target the sigma(1) protein may lead to putative potent anti-cocaine agents. Here, we synthetized substituted hydantoins with high affinity for the sigma(1) protein and evaluated their behavioral efficacy. Two pure enantiomers were designed and synthesized: tetrahydroisoquinoleine-hydantoin fused compounds 3 and 4. They increased cocaine-induced locomotor stimulation or sensitization. The most active enantiomer 4, facilitated CPP acquisition but failed to substitute for cocaine. When CPP was acquired with cocaine and then extinguished, 4 provoked reactivation of CPP. These observations showed that compound 4 shows a typical profile of sigma(1) protein activator, facilitating cocaine-induced behavioral effects. Preliminary ADME properties are in favour of an optimal therapeutic development. Such Tic-hydantoin compound may serve as a new effective agonist therapy in cocaine addiction.
    European neuropsychopharmacology: the journal of the European College of Neuropsychopharmacology 03/2009; 19(7):504-15. · 3.68 Impact Factor
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    ABSTRACT: Amodiaquine remains one of the most prescribed antimalarial 4-aminoquinoline. To assess the importance of the 4'-hydroxyl group and subsequent hydrogen bond in the antimalarial activity of amodiaquine (AQ), a series of new analogues in which this functionality was replaced by various amino groups was synthesized. The incorporation of a 3'-pyrrolidinamino group instead of the 3'-diethylamino function of AQ allowed the development of a parallel series of amopyroquine derivatives. The compounds were screened against both chloroquine (CQ)-sensitive and -resistant strains of Plasmodium falciparum and their cytotoxicity evaluated upon the MRC5 cell line. Antimalarial activity in a low nanomolar range was recorded showing that the 4'-hydroxy function can be successfully replaced by various amino substituents in terms of activity without any influence of the level of CQ-resistance of the strains. Furthermore the ability of the compounds to inhibit beta-hematin formation was measured in order to discuss the mechanism of action of these new compounds. Compounds 7d and 8d exhibit a high selectivity index and may be considered as promising leads for further development.
    Medicinal Chemistry 10/2008; 4(5):407-25. · 1.37 Impact Factor
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    ABSTRACT: In order to graft an amphiphilic polysaccharide to lipid nanocapsules, we present here a new method of dextran lipidation. The lipidation strategy is based on the formation of an oxime linkage between the amphiphilic hydroxylamine C16E20ONH2 and the reductive end of a 40 kDa dextran. This chemoselective reaction allows us to control the lipidation site and the number of lipid introduced on the dextran molecule. This new amphiphilic dextran was used to coat the surface of lipid nanocapsules. The coating efficiency was followed by dynamic light scattering and the presence of the polysaccharide was confirmed by (1)H NMR and observed by electronic microscopy.
    Bioconjugate Chemistry 08/2008; 19(7):1491-5. · 4.58 Impact Factor
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    ABSTRACT: In order to determine the real significance of the 4'-phenolic group in the antimalarial activity and/or cytotoxicity of amodiaquine (AQ), analogues for which this functionality was shifted or modified were synthesized. Good in vitro antimalarial activity was obtained for compounds unable to form intramolecular hydrogen bond. Among the compounds synthesized, new amino derivative 5 displayed the greatest selectivity index towards the most CQ-resistant strain tested and was active in mice infected by Plasmodium berghei.
    European Journal of Medicinal Chemistry 03/2008; 43(2):252-60. · 3.50 Impact Factor
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    ABSTRACT: A series of 4-anilinoquinolines bearing an amino side chain linked to the aromatic ring with a carbamate or an amide bond were synthesized and evaluated for their antimalarial activity and their cytotoxicity upon MRC-5 cells. Among the 17 compounds, a majority was found to be active in the low nanomolar range against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum in vitro with relative low cytotoxicity. Two compounds were then tested on mice infected by Plasmodium berghei and were found to exhibit reasonable in vivo activity.
    European Journal of Medicinal Chemistry 12/2007; 43(10):2045-55. · 3.50 Impact Factor
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    ABSTRACT: The use of chloroquine (CQ) for malaria treatment decrease in importance because of the development of CQ-resistant strains of Plasmodium falciparum. CQ and others 4-aminoquinolein drugs mode of action is based on their accumulation in the food vacuole and inhibition of heme degradation. Clinical use of amodiaquine (AQ), active against CQ-resistant strains, has been restricted for prophylactic use because of observed side effects reported in some cases. The observed drug toxicity is believed to be related to the formation of a quinone-imine oxidation metabolite. In order to block the 4' position and avoid the possible oxidation in vivo, to optimise the activity against CQ-resistant strains, a series of 4'-substituted new derivatives of 4'-deOHAQ have been designed. The products were synthesized using aryl-aryl and aryl-alkyl Suzuki coupling reactions. Antimalarial activities against CQ-resistant strains, inhibition of b-hematin polymerisation and cytotoxicity measurements on MRC-5 cell lines will be presented.
    Abstracts of Papers of the American Chemical Society. 01/2007; 234.

Publication Stats

135 Citations
77.63 Total Impact Points

Institutions

  • 2009–2014
    • University of Lille Nord de France
      Lille, Nord-Pas-de-Calais, France
  • 2008–2014
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2007–2008
    • Institut Pasteur
      Lutetia Parisorum, Île-de-France, France
  • 2005–2006
    • Lille Catholic University
      Lille, Nord-Pas-de-Calais, France
    • Province de Liège
      Luik, Walloon Region, Belgium