References of "De Pauw, Edwin"
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See detailProteomic analysis of telomerase inhibition by telomere specific ligands
Mazzucchelli, Gabriel ULg; Gabelica, Valérie ULg; Smargiasso, Nicolas ULg et al

in Anticancer Research (2008), 28(5c), 3257-3258

Telomeres consist of protein complexes and repeated ‘TTAGGG’ double strand DNA sequences ended by a 3’ single strand DNA of the same sequence. Progressive telomere shortening is observed in vitro upon ... [more ▼]

Telomeres consist of protein complexes and repeated ‘TTAGGG’ double strand DNA sequences ended by a 3’ single strand DNA of the same sequence. Progressive telomere shortening is observed in vitro upon cell divisions and with ageing in vivo. At a critical telomere length, shortened telomeres trigger a permanent growth arrest known as replicative senescence. Telomerase is an RNA-dependent DNA polymerase that extends telomeres by adding ‘TTAGGG’ repeats. It consists of a functional RNA component (hTR) which serves as template and a catalytic protein (hTERT) with reverse transcriptase activity. The expression of hTERT alone is sufficient for the immortalisation of cells. Telomerase is highly expressed in tumor cells but at very low level in most somatic cells. These observations make the telomerase an attractive target for anticancer strategies. One of these strategies relies on the use of drug candidates able to stabilize the particular telomere G-quadruplex DNA structures. The stabilization of these structures makes the telomere inaccessible for telomerase and thus inhibits telomerase activity. The effect of the hTERT transfection was first studied on the proteome of human WI38 fibroblast cells (1). Then, the proteome alteration response of hTERT transfected WI38 cells induced by the treatment of two G-quadruplexes ligands, telomestatin and TMPyP4, was analyzed. Both compounds can inhibit telomerase but have different selectivity for the different G-quadruplexes structures. Proteome analysis of the treated cells reveals that TMPyP4 induces much more protein expression alterations than telomestatin probably due to its poor selectivity. TMPyP4 induces especially a drastic down expression of the hnRNPs, a modulation of the proteasome pathway, an apparent decrease of the translation and an over expression of several molecular chaperones. Telomestatin induces in particular an over expression of the protein BCL2A1 which is involved in drug resistance of cancer cells and a probable increase of the translation. Both treatments have a common effect particularly on the molecular chaperone CCT (down expression), HSP90 alpha (over expression) and hnRNP D (down expression). The protein HSP90 alpha is also over expressed in hTERT transfected cells compared to parental cells. This protein is already a promising anticancer target protein due to its central role in oncogenesis and in telomerase activity regulation. 1 Mazzucchelli et al: Proteome Science 6: 12, 2008. [less ▲]

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See detailA short C-rich PNA fragment capable to form novel G-quadruplex-PNA complexes
Amato, Jussara; Gabelica, Valérie ULg; Borbone, Nicola et al

in Nucleic Acids Symposium Series (2008), 52

In this work we investigated the interaction between the short ac(4)a C-rich peptide nucleic acid (PNA) probe and two intramolecular G-quadruplex targets having the same G-tetrad core, but different ... [more ▼]

In this work we investigated the interaction between the short ac(4)a C-rich peptide nucleic acid (PNA) probe and two intramolecular G-quadruplex targets having the same G-tetrad core, but different folding topologies. The T(G(4)T)(3)G(4)T and the recently reported tetra-end-linked-(TG(4)T)(4) G-rich oligonucleotides (GROs) were chosen and synthesized for this study. UV, CD, and MS experiments revealed the formation of novel 1:1 G-quadruplex-PNA complexes besides the expected DNA-PNA heteroduplexes [less ▲]

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See detailLigand binding to tetra-end-linked (TGGGGT)4 G-quadruplexes: an electrospray mass spectroscopy study
Amato, Jussara; Oliviero, Giorgia; Borbone, Nicola et al

in Nucleic Acids Symposium Series (2008), 52

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the ... [more ▼]

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the 3' or 5'-end by a tetra-end-linker (TEL) unit were chosen as the ligands targets. The stoichiometries of the obtained complexes as well as the ligand affinity and selectivity to the different quadruplexes were determined to deduce the ligand binding site. The TEL derivatives I and II allowed the probing of the grooves contribution to the binding of ligands to G-quadruplexes, demonstrating that the 3' and 5' quartets are not equivalent binding sites for ligand end-stacking. [less ▲]

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See detailElectrospray Mass Spectrometry to Study Drug-Nucleic Acids Interactions
Rosu, Frédéric ULg; De Pauw, Edwin ULg; Gabelica, Valérie ULg

in Biochimie (2008), 90(7), 1074-1087

We present here a tutorial review on the electrospray mass spectrometry technique and its applications to the study of drug-nucleic acid non-covalent complexes. Particular emphasis has been made on the ... [more ▼]

We present here a tutorial review on the electrospray mass spectrometry technique and its applications to the study of drug-nucleic acid non-covalent complexes. Particular emphasis has been made on the basic principles of the technique, to allow even the non-specialist to design fit-for-purpose mass spectrometry experiments and interpret the results. Standard applications will be described in detail, including the determination of stoichiometries and equilibrium binding constants of non-covalent complexes, the study of binding kinetics, and the development of ligand screening assays. We also outline the potentials of more advanced and/or more recent MS-based techniques (tandem mass spectrometry, ion mobility spectrometry and gas-phase spectroscopy) for the study of the nucleic acid-ligand complexes. [less ▲]

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See detailInfrared Signature of DNA G-Quadruplexes in the Gas Phase
Gabelica, Valérie ULg; Rosu, Frédéric ULg; De Pauw, Edwin ULg et al

in Journal of the American Chemical Society (2008), 130(6), 1810-1

DNA oligonucleotide ions forming G-quadruplex structures were studied in the gas phase using IRMPD spectroscopy. Data interpretation on these large biomolecule ions was made using carefully chosen control ... [more ▼]

DNA oligonucleotide ions forming G-quadruplex structures were studied in the gas phase using IRMPD spectroscopy. Data interpretation on these large biomolecule ions was made using carefully chosen control experiments. The major finding is a fingerprint of hydrogen bonding in the gas phase in the guanine C6=O6 stretching mode, that allows probing the conservation of G-quartets in the gas phase. The experiments demonstrate the conservation of G-quadruplex hydrogen bonds in the human telomeric sequence d(TTAGGG)4. [less ▲]

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See detailCooperative 2:1 Binding of a Bisphenothiazine to Duplex DNA
Rosu, Frédéric ULg; Gabelica, Valérie ULg; De Pauw, Edwin ULg et al

in Chembiochem : A European Journal of Chemical Biology (2008), 9

Highly cooperative formation of a 2:1 complex was revealed by electrospray mass spectrometry experiments, and a structural model is proposed.

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See detailG-Quadruplex DNA Assemblies: Loop Length, Cation Identity, and Multimer Formation
Smargiasso, Nicolas ULg; Rosu, Frédéric ULg; Hsia, Wei et al

in Journal of the American Chemical Society (2008), 130(31), 10208-10216

G-rich DNA sequences are able to fold into structures called G-quadruplexes. To obtain general trends in the influence of loop length on the structure and stability of G-quadruplex structures, we studied ... [more ▼]

G-rich DNA sequences are able to fold into structures called G-quadruplexes. To obtain general trends in the influence of loop length on the structure and stability of G-quadruplex structures, we studied oligodeoxynucleotides with random bases in the loops. Sequences studied are dGGGWiGGGWjGGGWkGGG, with W = thymine or adenine with equal probability, and i, j, and k comprised between 1 and 4. All were studied by circular dichroism, native gel electrophoresis, UV-monitored thermal denaturation, and electrospray mass spectrometry, in the presence of 150 mM potassium, sodium, or ammonium cations. Parallel conformations are favored by sequences with short loops, but we also found that sequences with short loops form very stable multimeric quadruplexes, even at low strand concentration. Mass spectrometry reveals the formation of dimers and trimers. When the loop length increases, preferred quadruplex conformations tend to be more intramolecular and antiparallel. The nature of the cation also has an influence on the adopted structures, with K+ inducing more parallel multimers than NH4+ and Na+. Structural possibilities are discussed for the new quadruplex higher-order assemblies. [less ▲]

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See detailAnalytical Measurement and Levelsof Dioxins and PCBs in Biological Samples
Focant, Jean-François ULg; Eppe, Gauthier ULg; De Pauw, Edwin ULg

in Faye, Bernard; Sinyavskiy, Youri (Eds.) Impact of Pollution on Animal Products (2008)

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See detailPhotodissociation spectroscopy of cationic porphyrins in the gas phase. Influence of the complexation with DNA. Comparison with solution phase
Rosu, Frédéric ULg; De Pauw, Edwin ULg; Gabelica, Valérie ULg et al

in Beck, Rainer D.; Drabbels, Marcel; Rizzo, Thomas R. (Eds.) Contributions 16th Symposium on Atomic and Surface Physics and Related Topics (2008)

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See detailCell membrane proteomic analysis identifies proteins differentially expressed in osteotropic human breast cancer cells.
Kischel, Philippe ULg; Guillonneau, Francois; Dumont, Bruno ULg et al

in Neoplasia : An International Journal for Oncology Research (2008), 10(9), 1014-20

Metastatic breast cancer cells are characterized by their high propensity to colonize the skeleton and form bone metastases, causing major morbidity and mortality. Identifying key proteins involved in the ... [more ▼]

Metastatic breast cancer cells are characterized by their high propensity to colonize the skeleton and form bone metastases, causing major morbidity and mortality. Identifying key proteins involved in the osteotropic phenotype would represent a major step toward the development of both new prognostic markers and new effective therapies. Cell surface proteins differentially expressed in cancer cells are preferred potential targets for antibody-based targeted therapies. In this study, using cell surface biotinylation and a mass spectrometric approach, we have compared the profile of accessible cell surface proteins between the human breast cancer cell line MDA-MB-231 and its highly osteotropic B02 subclone. This strategy allowed the identification of several proteins either up- or downregulated in the osteotropic cell line, and differential protein expressions were validated using antibody-based techniques. Class I HLAs were down-regulated in the bone metastatic variant, whereas alpha(v)beta(3) integrins, among others, were consistently up-regulated in this latter cell line. These results show that comprehensive profiling of the cell surface proteome of mother cancerous cell lines and derived organ-specific metastatic cell lines provides an effective approach for the identification of potential accessible marker proteins for both prognosis and antibody-based targeted therapies. [less ▲]

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See detailIdentification of aphid salivary proteins: a proteomic investigation of Myzus persicae.
Harmel, Nicolas ULg; Letocart, E.; Cherqui, A. et al

in Insect Molecular Biology (2008), 17(2), 165-74

The role of insect saliva in the first contact between an insect and a plant is crucial during feeding. Some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence ... [more ▼]

The role of insect saliva in the first contact between an insect and a plant is crucial during feeding. Some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence reactions. Here, we focused on the salivary proteome of the green peach aphid, Myzus persicae. Proteins were either directly in-solution digested or were separated by 2D SDS-PAGE before trypsin digestion. Resulting peptides were then identified by mass spectrometry coupled with database investigations. A homemade database was constituted of expressed sequence tags from the pea aphid Acyrtosiphon pisum and M. persicae. The databases were used to identify proteins related to M. persicae with a nonsequenced genome. This procedure enabled us to discover glucose oxidase, glucose dehydrogenase, NADH dehydrogenase, alpha-glucosidase and alpha-amylase in M. persicae saliva. The presence of these enzymes is discussed in terms of plant-aphid interactions. [less ▲]

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See detailDioxin-like compounds in porpoises and seals from the southern North Sea: relationship with biological and ecological factors
Das, Krishna ULg; De Pauw, Edwin ULg; Eppe, Gauthier ULg et al

in Organohalogen Compounds (2008), 70

The North Sea represents a major ecosystem for the harbour porpoise (Phocoena phocoena) and the harbour seal (Phoca vitulina). The grey seal (Halichoerus grypus) occurs more occasionally in the southern ... [more ▼]

The North Sea represents a major ecosystem for the harbour porpoise (Phocoena phocoena) and the harbour seal (Phoca vitulina). The grey seal (Halichoerus grypus) occurs more occasionally in the southern part of the North Sea. Their population over this last decade has experienced major fluctuations likely linked to prey availability and seal epizootics. Despite being banned more than 30 years ago, levels of polychlorinated biphenyls (PCBs) in marine mammals are still of concern due to historical contamination of the North Sea. [less ▲]

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See detailProteome alteration induced by hTERT transfection of human fibroblast cells
Mazzucchelli, Gabriel ULg; Gabelica, Valérie ULg; Smargiasso, Nicolas ULg et al

in Proteome Science (2008), 6(1), 12

Background: Telomerase confers cellular immortality by elongating telomeres, thereby circumventing the Hayflick limit. Extended-life-span cells have been generated by transfection with the human ... [more ▼]

Background: Telomerase confers cellular immortality by elongating telomeres, thereby circumventing the Hayflick limit. Extended-life-span cells have been generated by transfection with the human telomerase reverse transcriptase (hTERT) gene. hTERT transfected cell lines may be of outstanding interest to monitor the effect of drugs targeting the telomerase activity. The incidence of hTERT gene transfection at the proteome level is a prerequisite to that purpose. The effect of the transfection has been studied on the proteome of human fibroblast (W138). Cytosolic and nuclear fractions of W138 cells, empty vector transfected W138 (W138-HPV) and hTERT W138 cells were submitted to a 2D-DIGE (Two-Dimensional Differential In-Gel Electrophoresis) analysis. Only spots that had a similar abundance in W138 and W138-HPV, but were differentially expressed in W138 hTERT were selected for MS identification. This method directly points to the proteins linked with the hTERT expression. Number of false positive differentially expressed proteins has been excluded by using control W138-HPV cells. The proteome alteration induced by hTERT W138 transfection should be taken into account in subsequent use of the cell line for anti-telomerase drugs evaluation. Results: 2D-DIGE experiment shows that 57 spots out of 2246 are significantly differentially expressed in the cytosolic fraction due to hTERT transfection, and 38 were confidently identified. In the nuclear fraction, 44 spots out of 2172 were selected in the differential proteome analysis, and 14 were identified. The results show that, in addition to elongating telomeres, hTERT gene transfection has other physiological roles, among which an enhanced ER capacity and a potent cell protection against apoptosis. Conclusion: We show that the methodology reduces the complexity of the proteome analysis and highlights proteins implicated in other processes than telomere elongation. hTERT induced proteome changes suggest that telomerase expression enhances natural cell repair mechanisms and stress resistance probably required for long term resistance of immortalized cells. Thus, hTERT transfected cells can not be only consider as an immortal equivalent to parental cells but also as cells which are over-resistant to stresses. These findings are the prerequisite for any larger proteomics aiming to evaluate anti-telomerase drugs proteome alteration and thus therapeutics induced cell reactions. [less ▲]

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See detailLNCaP prostate cancer imaging with biologically functionalized gold nanoparticles in 2D and 3D cell culture
Schol, Daureen ULg; Fleron, Maximilien ULg; Greisch, Jean - François et al

in Anticancer Research (2008), 28

One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g ... [more ▼]

One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g. prostate cancer. Gold nanorods have been synthesized and functionalized with antibodies targeting specific antigens on cancer cell lines. [less ▲]

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See detailA SYSTEMS BIOLOGY APPROACH TARGETING NEUROLOGICAL DISEASE- FROM GENOMICS TO IN SILICO PREDICTIVE MODELS
Vafiadaki, Elizabeth; Depaulis, Antoine; Jackers, Pascale ULg et al

Poster (2007, December 07)

VALAPODYN, a European Commission funded research network, is constructing an original system biology approach for the development of multidisciplinary functional genomics related to complex biological ... [more ▼]

VALAPODYN, a European Commission funded research network, is constructing an original system biology approach for the development of multidisciplinary functional genomics related to complex biological processes and cellular networks. The aim is to generate an innovative model on the dynamics of molecular interaction networks (MIN) in relation to cell death and survival for the detection of new therapeutic targets to treat human brain diseases. Proteomic databases are being used along with leading microarray and proteomics platform systems to investigate protein-protein interactions and regulation networks. This will help to identify and validate biological targets in complex intracellular pathways to cure multifactorial diseases. Dynamic modeling specifically addresses the systems biology of complex cellular pathways and transcriptional networks. Novel dynamic models will be validated by testing the selected drug targets on innovative in vivo and in vitro models of CNS pathologies. The first phase involves fundamental genomics research, integrating statistical data analysis with real biological data in order to functionally annotate genes and proteins. Using Affymetrix microarrays, we are evaluating whole genome expression profiles generated from dissected mouse brains following different treatments at various time points. Through the simultaneous analysis of ~40,000 genes, critical pathways and molecular targets implicated in neurodegeneration are being revealed. VALAPODYN develops a dynamic and quantitative analysis method for new therapeutic targets through MIN dynamic models. It will provide a cutting-edge highly accurate in silico tool for identifying novel and effective therapeutic targets in a faster, more efficient and more economical way than it is possible today. (www.valapodyn.eu). dsanoudou@bioacademy.gr [less ▲]

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See detailOptoacoustic specific detection of prostate cancer using functionalized gold nanorods
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, November 16)

A major challenge in prostate cancer oncology is to develop more accurate imaging assessments than those currently available. Indeed, an efficient imaging technique which significantly improves the ... [more ▼]

A major challenge in prostate cancer oncology is to develop more accurate imaging assessments than those currently available. Indeed, an efficient imaging technique which significantly improves the sensitivity and specificity of the diagnostic and predicting the cancer behaviour would be extremely valuable. This project intends to prove the concept of using optoacoustic imaging in combination with biologically functionalized nanoparticles as an integrated biosensor based system for the production of specific and sensitive data for accurate diagnosis of prostate cancer. This concept results on the use of contrast agents which transform an incident luminous energy into local heating inducing a pressure wave detectable by acoustic (echography). For the optoacoustic detection, the nanoparticles used must present a maximum of absorption in the optical transparency window of the human tissues in order to allow their and subsequently the tissue specific excitations while avoiding unwanted destructive energy transfers. According to these characteristics (energy transfer by thermoelastic reaction), rod-like gold nanoparticles (stick form) with a maximum of absorption towards 760 nm were produced by using a “bottom-up” approach with dynamic templates (surfactant). These nanoparticles are then coupled with an antibody directed against the cancerous cells to guarantee the specific detection of the particles. The development of the biosensor is firstly performed to target the Prostate Specific Membrane Antigen (PSMA), a transmembrane protein considered as a suitable biomarker for prostate cancer. Detection and localisation of PSMA on LNCaP fixed cell surface was performed by immunostainning on monolayer cell culture and on spheroid slices. Then, by backscattered electron (BSE) microscopy analysis and two-photon luminescence imaging, detection of nanoparticles on fixed and living cell surface shows the successful binding of the biosensor to the cells expressing PSMA. In prospect, the detection of the biosensor will be tested on spheroids, on human biopsies and finally on in vivo models (mouse xenograft models). [less ▲]

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See detailMCF-7/BOS cells membrane proteome profiling for the analysis of plasmic proteins in pancreatic beta cells
Bertrand, Virginie ULg; Massart, Anne-Cécile; Flamez, Daisy et al

Poster (2007, October 11)

Type I and type II diabetes are diseases characterized by the activation of the apoptotic processes in pancreatic islet of beta-cells. To highlight specific proteins of beta cells in medical imaging ... [more ▼]

Type I and type II diabetes are diseases characterized by the activation of the apoptotic processes in pancreatic islet of beta-cells. To highlight specific proteins of beta cells in medical imaging (positron emission tomography or PET), the development of antibodies directed against membrane markers of the beta cells is undertaken. These membrane markers have to be accessible to antibodies and should be potential therapeutic targets. In order to isolate membrane proteins of beta cells, preliminary tests were conducted on MCF-7 / BOS cell line, immortal and easier to cultivate. The goal of this work is to obtain a pure membrane fraction to facilitate the analysis of the sample. To isolate transmembrane proteins, we compared two methods. The first one used a differential centrifugation to isolate membrane proteins. The second method labelled accessible extracellular domains at the surface of MCF-7 cells with biotin prior to differential centrifugation. Our results shown that the labelling technique can provide 50% of membrane proteins. This second method will be used to isolate membrane proteins of pancreatic beta cells. [less ▲]

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