LEFEBVRE-TOURNIER Isabelle
Fonction : user SAP
Thème de Recherche: Nucléosides & Effecteurs Phosphorylés
isabelle.tournier
umontpellier.fr
0448792055
Bureau: N1H14 - Site : Pôle Chimie Balard Recherche
Domaines de Recherche: - Sciences du Vivant/Cancer
- Sciences du Vivant/Biologie cellulaire/Organisation et fonctions cellulaires
- Physique/Matière Condensée/Science des matériaux
- Physique/Physique Quantique
- Chimie/Cristallographie
- Chimie/Matériaux
- Chimie/Chimie organique
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Dernieres productions scientifiques :
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The cytosolic 5’-nucleotidase cN-II lowers the adaptability to glucose deprivation in human breast cancer cells
Auteur(s): Bricard Gabriel, Cadassou Octavia, Cassagnes Laure-Estelle, Cros-Perrial Emeline, Payen-Gay Léa, Puy J.-Y., Lefebvre-Tournier I., Tozzi Maria Grazia, Dumontet Charles, Jordheim Lars Petter
(Article) Publié:
Oncotarget, vol. p. (2017)
Ref HAL: hal-01611275_v1
DOI: 10.18632/oncotarget.18653
Résumé: The cytosolic 5'-nucleotidase cN-II is a highly conserved enzyme implicated in nucleotide metabolism. Based on recent observations suggesting additional roles not directly associated to its enzymatic activity, we studied human cancer cell models with basal or decreased cN-II expression. We developed cancer cells with stable inhibition of cN-II expression by transfection of shRNA-coding plasmids, and studied their biology. We show that human breast cancer cells MDA-MB-231 with decreased cN-II expression better adapt to the disappearance of glucose in growth medium under normoxic conditions than cells with a baseline expression level. This is associated with enhanced in vivo growth and a lower content of ROS in cells cultivated in absence of glucose due to more efficient mechanisms of elimination of ROS. Conversely, cells with low cN-II expression are more sensitive to glucose deprivation in hypoxic conditions. Overall, our results show that cN-II regulates the cellular response to glucose deprivation through a mechanism related to ROS metabolism and defence.
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Determination and quantification of intracellular fludarabine triphosphate, cladribine triphosphate and clofarabine triphosphate by LC-MS/MS in human cancer cells.
Auteur(s): Puy J.-Y., Jordheim Lars Petter, Cros-Perrial Emeline, Dumontet Charles, Peyrottes S., Lefebvre-Tournier I.
(Article) Publié:
-Journal Of Chromatography B Analytical Technologies In The Biomedical And Life Sciences, vol. 1053 p.101-110 (2017)
Ref HAL: hal-01567793_v1
PMID 28415014
Résumé: Purine nucleoside analogues are widely used in the treatment of haematological malignancies, and their biological activity is dependent on the intracellular accumulation of their triphosphorylated metabolites. In this context, we developed and validated a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to study the formation of 5'-triphosphorylated derivatives of cladribine, fludarabine, clofarabine and 2'-deoxyadenosine in human cancer cells. Br-ATP was used as internal standard. Separation was achieved on a hypercarb column. Analytes were eluted with a mixture of hexylamine (5 mM), DEA (0.4%, v/v, pH 10.5) and acetonitrile, in a gradient mode at a flow rate of 0.3mLmin(-1). Multiple reactions monitoring (MRM) and electrospray ionization in negative mode (ESI-) were used for detection. The application of this method to the quantification of these phosphorylated cytotoxic compounds in a human follicular lymphoma cell line, showed that it was suitable for the study of relevant biological samples.
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Type I band alignment in GaAs 81 Sb 19 /GaAs core-shell nanowires
Auteur(s): Xu T., Wei M., CAPIOD P., Díaz Álvarez A., Han X., Troadec D., Nys P., Berthe M., Lefebvre-Tournier I., Patriarche G., Plissard Sébastien, Caroff P., Ebert Ph., Grandidier B.
(Article) Publié:
Applied Physics Letters, vol. 107 p.112102 (2015)
Ref HAL: hal-01713079_v1
DOI: 10.1063/1.4930991
Résumé: The composition and band gap of the shell that formed during the growth of axial GaAs/GaAs81Sb19/ GaAs heterostructure nanowires have been investigated by transmission electron microscopy combined with energy dispersion spectroscopy, scanning tunneling spectroscopy, and density functional theory calculations. On the GaAs81Sb19 intermediate segment, the shell is found to be free of Sb (pure GaAs shell) and transparent to the tunneling electrons, despite the (110) biaxial strain that affects its band gap. As a result, a direct measurement of the core band gap allows the quantitative determination of the band offset between the GaAs81Sb19 core and the GaAs shell and identifies it as a type I band alignment.
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Fully validated assay for the quantification of endogenous nucleoside mono- and triphosphates using online extraction coupled with liquid chromatography-tandem mass spectrometry.
Auteur(s): Machon Christelle, Jordheim Lars Petter, Puy J.-Y., Lefebvre-Tournier I., Dumontet Charles, Guitton Jérome
(Article) Publié:
Analytical And Bioanalytical Chemistry, vol. 406 p.2925-2941 (2014)
Ref HAL: hal-01004663_v1
DOI: 10.1007/s00216-014-7711-1
Résumé: An analytical method coupling online solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to quantify 16 endogenous nucleoside mono- and triphosphates in cellular samples. Separation was achieved on a porous graphitic carbon (PGC) column without ion-pairing agent in the mobile phase. Low levels of the ion-pairing agent diethylamine (DEA) added to the reconstitution solution were necessary to prevent peak tailing of nucleoside triphosphates. The mass spectrometer, a triple quadrupole with an electrospray ionisation source, was operated in positive mode. Two multiple reaction monitoring (MRM) segments were programmed, each an internal standard. Extraction and separation of nucleoside mono- and triphosphates were obtained within 20 min. The total duration of a single run was 37 min. Calibration curves, performed with labelled nucleotides added to the sample matrix, ranged from 0.29 to 18.8 pmol injected for deoxyribonucleotides and from 3.9 to 3,156 pmol for ribonucleotides. Accuracy did not deviate more than −14.6 and 10.2 % from nominal values for all compounds at all levels. CV results were all lower than 17.0 % for the LLOQ level and 14.6 % for the other levels. Quality control (QC) samples were also in agreement with acceptance criteria, except for the lower QC of GMP. Ion suppression, matrix effect, extraction recoveries and stability were assessed. After validation, the method was applied to the evaluation of the effects of gemcitabine and hydroxyurea on nucleotide pools in Messa cells.
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A quantitative liquid chromatography tandem mass spectrometry method for metabolomic analysis of Plasmodium falciparum lipid related metabolites
Auteur(s): Lefebvre-Tournier I.
(Article) Publié:
Analytica Chimica Acta, vol. 739 p.47-55 (2012)
Ref HAL: hal-00733183_v1
Résumé: Plasmodium falciparum is the causative agent of malaria, a deadly infectious disease for which treatments are scarce and drug-resistant parasites are now increasingly found. A comprehensive method of identifying and quantifying metabolites of this intracellular parasite could expand the arsenal of tools to understand its biology, and be used to develop new treatments against the disease. Here, we present two methods based on liquid chromatography tandem mass spectrometry for reliable measurement of water-soluble metabolites involved in phospholipid biosynthesis, as well as several other metabolites that reflect the metabolic status of the parasite including amino acids, carboxylic acids, energy-related carbohydrates, and nucleotides. A total of 35 compounds was quantified. In the first method, polar compounds were retained by hydrophilic interaction chromatography (amino column) and detected in negative mode using succinic acid-13C4and fluorovaline as internal standards. In the second method, separations were carried out using reverse phase (C18) ion-pair liquid chromatography, with heptafluorobutyric acid as a volatile ion pairing reagent in positive detection mode, using d9-choline and 4-aminobutanol as internal standards. Standard curves were performed in P. falciparum-infected and uninfected red blood cells using standard addition method (r2> 0.99). The intra- and inter-day accuracy and precision as well as the extraction recovery of each compound were determined. The lower limit of quantitation varied from 50 pmol to 100 fmol/3 × 107cells. These methods were validated and successfully applied to determine intracellular concentrationsofmetabolitesfromuninfectedhostRBCsandisolatedPlasmodiumparasites.
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