UMR9187 / U1196 – Chimie et Modélisation pour la Biologie du Cancer (CMBC)

Publications de l’unité

Année de publication : 2016

Jessy Aziz, Tom Baladi, Sandrine Piguel (2016 Apr 26)

Direct Alkynylation of 3H-Imidazo[4,5-b]pyridines Using gem-Dibromoalkenes as Alkynes Source.

The Journal of organic chemistry : 81 : 4122-4133 : DOI : 10.1021/acs.joc.6b00406 En savoir plus
Résumé

C2 direct alkynylation of 3H-imidazo[4,5-b]pyridine derivatives is explored for the first time. Stable and readily available 1,1-dibromo-1-alkenes, electrophilic alkyne precursors, are used as coupling partners. The simple reaction conditions include an inexpensive copper catalyst (CuBr·SMe2 or Cu(OAc)2), a phosphine ligand (DPEphos) and a base (LiOtBu) in 1,4-dioxane at 120 °C. This C-H alkynylation method revealed to be compatible with a variety of substitutions on both coupling partners: heteroarenes and gem-dibromoalkenes. This protocol allows the straightforward synthesis of various 2-alkynyl-3H-imidazo[4,5-b]pyridines, a valuable scaffold in drug design.

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Anne Cammas, Magali Lacroix-Triki, Sandra Pierredon, Morgane Le Bras, Jason S Iacovoni, Marie-Paule Teulade-Fichou, Gilles Favre, Henri Roché, Thomas Filleron, Stefania Millevoi, Stéphan Vagner (2016 Mar 29)

hnRNP A1-mediated translational regulation of the G quadruplex-containing RON receptor tyrosine kinase mRNA linked to tumor progression.

Oncotarget : 7 : 16793-16805 : DOI : 10.18632/oncotarget.7589 En savoir plus
Résumé

The expression and role of RNA binding proteins (RBPs) controlling mRNA translation during tumor progression remains largely uncharacterized. Analysis by immunohistochemistry of the expression of hnRNP A1, hnRNPH, RBM9/FOX2, SRSF1/ASF/SF2, SRSF2/SC35, SRSF3/SRp20, SRSF7/9G8 in breast tumors shows that the expression of hnRNP A1, but not the other tested RBPs, is associated with metastatic relapse. Strikingly, hnRNP A1, a nuclear splicing regulator, is also present in the cytoplasm of tumor cells of a subset of patients displaying exceedingly worse prognosis. Expression of a cytoplasmic mutant of hnRNP A1 leads to increased translation of the mRNA encoding the tyrosine kinase receptor RON/MTS1R, known for its function in tumor dissemination, and increases cell migration in vitro. hnRNP A1 directly binds to the 5′ untranslated region of the RON mRNA and activates its translation through G-quadruplex RNA secondary structures. The correlation between hnRNP A1 and RON tumoral expression suggests that these findings hold clinical relevance.

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Morgan Pellerano, Delphine Naud-Martin, Marion Peyressatre, Camille Prével, Marie-Paule Teulade-Fichou, May Morris, Florence Mahuteau-Betzer (2016 Mar 17)

TP-2Rho Is a Sensitive Solvatochromic Red-Shifted Probe for Monitoring the Interactions between CDK4 and Cyclin D.

Chembiochem : a European journal of chemical biology : 17 : 737-744 : DOI : 10.1002/cbic.201500641 En savoir plus
Résumé

Understanding the intricate steps of protein kinase regulation requires characterization of protein-protein interactions between the catalytic subunit, its regulatory partners and the substrate. Fluorescent probes are useful tools with which to study such interactions and to gain insight into their affinities and specificities. Solvatochromic probes, which display changes in their fluorescence emission in response to changes in the polarity of the medium, are particularly attractive. Here we describe conjugation of a switchable fluorescent dye, TP-2Rho, to peptide and protein derivatives of cyclin-dependent kinase 4 (CDK4) and its application to characterization of the interactions between the catalytic subunit of this kinase, its regulatory partner cyclin D1 and a peptide substrate. We demonstrate the sensitivity of TP-2Rho in relation to of those other dyes used for monitoring peptide-protein and protein-protein interactions. Moreover, we show that TP-Rho-labelled peptides can be introduced into living cells to probe endogenous CDK4/cyclin D.

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Rahima Chennoufi, Houcine Bougherara, Nathalie Gagey-Eilstein, Blaise Dumat, Etienne Henry, Frédéric Subra, Stéphanie Bury-Moné, Florence Mahuteau-Betzer, Patrick Tauc, Marie-Paule Teulade-Fichou, Eric Deprez (2016 Mar 8)

Mitochondria-targeted Triphenylamine Derivatives Activatable by Two-Photon Excitation for Triggering and Imaging Cell Apoptosis.

Scientific reports : 6 : 21458 : DOI : 10.1038/srep21458 En savoir plus
Résumé

Photodynamic therapy (PDT) leads to cell death by using a combination of a photosensitizer and an external light source for the production of lethal doses of reactive oxygen species (ROS). Since a major limitation of PDT is the poor penetration of UV-visible light in tissues, there is a strong need for organic compounds whose activation is compatible with near-infrared excitation. Triphenylamines (TPAs) are fluorescent compounds, recently shown to efficiently trigger cell death upon visible light irradiation (458 nm), however outside the so-called optical/therapeutic window. Here, we report that TPAs target cytosolic organelles of living cells, mainly mitochondria, triggering a fast apoptosis upon two-photon excitation, thanks to their large two-photon absorption cross-sections in the 760-860 nm range. Direct ROS imaging in the cell context upon multiphoton excitation of TPA and three-color flow cytometric analysis showing phosphatidylserine externalization indicate that TPA photoactivation is primarily related to the mitochondrial apoptotic pathway via ROS production, although significant differences in the time courses of cell death-related events were observed, depending on the compound. TPAs represent a new class of water-soluble organic photosensitizers compatible with direct two-photon excitation, enabling simultaneous multiphoton fluorescence imaging of cell death since a concomitant subcellular TPA re-distribution occurs in apoptotic cells.

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Katharina Ernst, Markus Liebscher, Sebastian Mathea, Anton Granzhan, Johannes Schmid, Michel R Popoff, Heiko Ihmels, Holger Barth, Cordelia Schiene-Fischer (2016 Feb 4)

A novel Hsp70 inhibitor prevents cell intoxication with the actin ADP-ribosylating Clostridium perfringens iota toxin.

Scientific reports : 6 : 20301 : DOI : 10.1038/srep20301 En savoir plus
Résumé

Hsp70 family proteins are folding helper proteins involved in a wide variety of cellular pathways. Members of this family interact with key factors in signal transduction, transcription, cell-cycle control, and stress response. Here, we developed the first Hsp70 low molecular weight inhibitor specifically targeting the peptide binding site of human Hsp70. After demonstrating that the inhibitor modulates the Hsp70 function in the cell, we used the inhibitor to show for the first time that the stress-inducible chaperone Hsp70 functions as molecular component for entry of a bacterial protein toxin into mammalian cells. Pharmacological inhibition of Hsp70 protected cells from intoxication with the binary actin ADP-ribosylating iota toxin from Clostridium perfringens, the prototype of a family of enterotoxins from pathogenic Clostridia and inhibited translocation of its enzyme component across cell membranes into the cytosol. This finding offers a starting point for novel therapeutic strategies against certain bacterial toxins.

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Chaput L., Martinez-Sanz J., Quiniou E., Rigolet P., Saettel N., Mouawad L. (2016 Jan 18)

vSDC: a method to improve early recognition in virtual screening when limited experimental resources are available

Journal of Cheminformatics : 8:1 : DOI : 10.1186/s13321-016-0112-z En savoir plus
Résumé

Background: In drug design, one may be confronted to the problem of finding hits for targets for which no small inhibiting molecules are known and only low-throughput experiments are available (like ITC or NMR studies), two common difficulties encountered in a typical academic setting. Using a virtual screening strategy like docking can alleviate some of the problems and save a considerable amount of time by selecting only top-ranking molecules, but only if the method is very efficient, i.e. when a good proportion of actives are found in the 1-10 % best ranked molecules.

Results: The use of several programs (in our study, Gold, Surflex, FlexX and Glide were considered) shows a divergence of the results, which presents a difficulty in guiding the experiments. To overcome this divergence and increase the yield of the virtual screening, we created the standard deviation consensus (SDC) and variable SDC (vSDC) methods, consisting of the intersection of molecule sets from several virtual screening programs, based on the standard deviations of their ranking distributions.

Conclusions: SDC allowed us to find hits for two new protein targets by testing only 9 and 11 small molecules from a chemical library of circa 15,000 compounds. Furthermore, vSDC, when applied to the 102 proteins of the DUD-E benchmarking database, succeeded in finding more hits than any of the four isolated programs for 13-60 % of the targets. In addition, when only 10 molecules of each of the 102 chemical libraries were considered, vSDC performed better in the number of hits found, with an improvement of 6-24 % over the 10 best-ranked molecules given by the individual docking programs.

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Blaise Dumat, Elodie Faurel-Paul, Pauline Fornarelli, Nicolas Saettel, Germain Metgé, Céline Fiorini-Debuisschert, Fabrice Charra, Florence Mahuteau-Betzer, Marie-Paule Teulade-Fichou (2016 Jan 7)

Influence of the oxazole ring connection on the fluorescence of oxazoyl-triphenylamine biphotonic DNA probes.

Organic & biomolecular chemistry : 14 : 358-370 : DOI : 10.1039/c5ob02225h En savoir plus
Résumé

On the basis of our previous work on DNA fluorophores derived from vinylpyridinium-triphenylamine, we explored the structure space around the electron-rich triphenylamine (TP) core by changing the vinyl bond to an oxazole ring. As 2,5-diaryloxazoles are known to be highly fluorescent and efficient two photon absorbers, we synthesized analogues with two different connections of the oxazole to the triphenylamine core: TP-Ox2Py and TP-Ox5Py sets. Since the benzimidazolium group was proven to be more effective in the TP series than the pyridinium, we also synthesized a TP-Ox5Bzim set. The TP-Ox5Py series retains the TP-Py properties: on/off behavior on DNA, good two-photon cross-section and bright staining of nuclear DNA by microscopy under both one or two-photon excitation. On the other hand, the TP-Ox2Py series does not display fluorescence upon binding to DNA. The TP-Ox5Bzim set is fluorescent even in the absence of DNA and displays lower affinity than the corresponding TP-Ox5Py. CD experiments and docking were performed to understand these different behaviors.

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Topkaya D., Lafont D., Poyer F., Garcia G., Albrieux F., Maillard P., Bretonniere Y., Dumoulin F. (2016 Jan 1)

Design of an amphiphilic porphyrin exhibiting high in vitro photocytotoxicity

NEW JOURNAL OF CHEMISTRY : 40 : 2044-2050 : DOI : 10.1039/c5nj02716k En savoir plus
Résumé

A porphyrin monosubstituted by three triethyleneglycol chains grafted on a pentaerythritol skeleton was designed to display an optimized amphiphilicity for an enhanced cellular uptake and thus to exert enhanced photocytotoxicity. This porphyrin proved to be an excellent photosensitiser with submicromolar IC50.

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Morel E., Poyer F., Vaslin L., Bombard S., Teulade-Fichou M.P. (2016 Jan 1)

Photoactivatable platinum(II) terpyridine derivatives for G-quadruplex DNA double anchoring

Inorganica Chimica Acta : 452 : 152-158 : DOI : 10.1016/j.ica.2016.02.033 En savoir plus
Résumé

Platinum(II) tolylterpyridine (ttpy) complexes, have been shown to generate monofunctional adducts with various G-quadruplex DNA forming sequences resulting from an efficient π-stacking mode on the top of the quadruplex structure. To further explore the potential of this series with regard to quadruplex recognition, classical photocrosslinking groups (benzophenone, tetraphenylazide) have been grafted on the tolylterpyridine ligand moiety, thereby generating two new derivatives Pt-ttpy-Bn and Pt-ttpy-N3. Evaluation of their non-covalent binding for G-quadruplex DNA has been performed by FRET-melting and FID assays using two G-quadruplex matrices i.e. the telomeric sequence 22AG and the oncogene promotor sequence c-myc, which revealed high affinity and improved selectivity as compared to the parent compound. Subsequently the capacity of the compounds to establish one or two anchorage points (one by platination, one by photoinduced crosslinking) with the quadruplexes has been studied by gel electrophoresis with and without photoactivation. Interestingly both compounds do platinate the quadruplexes studied with high selectivity as the platination yield is poorly affected by the presence of duplex competitor. By contrast, only the azido derivative Pt-ttpy-N3 was found to form a second covalent bond within the G-quadruplexes upon photoactivation indicating a higher confinement of the crosslinking moiety in this case. Finally the two compounds exhibit poor cytotoxicity in the dark on two cancer cell lines (A2780 and HT29), whereas that of the benzophenone derivative is significantly enhanced upon irradiation. Altogether the two new compounds represent novel prototypes usable for trapping G4 DNA alone or eventually G4-DNA protein interactions in complex in vitro systems or in cells. [Metal-Nucleic Acid Interactions: State of the Art ]

G-quadruplex structures are substrate for ligand double anchorage using azido but not benzophenone photoactivable platinum(II) terpyridine complexes.
G-quadruplex structures are substrate for ligand double anchorage using azido but not benzophenone photoactivable platinum(II) terpyridine complexes.

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Lupu Mihaela, Thomas Carole D., Poyer Florent, Mispelter Joël, Rosilio Véronique, Maillard Philippe (2016 Jan 1)

Photobiology and photochemistry hand-in-hand in targeted antitumoral therapies

Handbook of Porphyrin Science : 39 : 171-356 : DOI : 10.1142/9789813149595_0005 En savoir plus
Résumé

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Année de publication : 2015

Anton Granzhan, Heiko Ihmels and Maoqun Tian (2015 Dec 1)

The benzo[b]quinolizinium ion as a water-soluble platform for the fluorimetric detection of biologically relevant analytes

ARKIVOC : 2015 : 494-523 : DOI : 10.3998/ark.5550190.p009.339 En savoir plus
Résumé

In this Account our efforts are described to establish the benzo[b]quinolizinium ion, also known as acridizinium or 4a-azoniaanthracene, as a water-soluble surrogate of anthracene for the development of selective fluorescent probes. It is demonstrated with selected examples that especially the 9-aminobenzo[b]quinolizinium is a donor-acceptor dye with favorable absorption and emission properties and may be used as a versatile building block for fluorescent light-up probes and ratiometric probes.

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Tom Baladi, Valentina Abet, Sandrine Piguel (2015 Nov 13)

State-of-the-art of small molecule inhibitors of the TAM family: the point of view of the chemist.

European journal of medicinal chemistry : 105 : 220-37 : DOI : 10.1016/j.ejmech.2015.10.003 En savoir plus
Résumé

The TAM family of tyrosine kinases receptors (Tyro3, Axl and Mer) is implicated in cancer development, autoimmune reactions and viral infection and is therefore emerging as an effective and attractive therapeutic target. To date, only a few small molecules have been intentionally designed to block the TAM kinases, while most of the inhibitors were developed for blocking different protein kinases and then identified through selectivity profile studies. This minireview will examine in terms of chemical structure the different compounds able to act on either one, two or three TAM kinases with details about structure-activity relationships, drug-metabolism and pharmacokinetics properties where they exist.

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Matjaž Bončina, Črtomir Podlipnik, Ivo Piantanida, Julita Eilmes, Marie-Paule Teulade-Fichou, Gorazd Vesnaver, Jurij Lah (2015 Nov 8)

Thermodynamic fingerprints of ligand binding to human telomeric G-quadruplexes.

Nucleic acids research : 43 : 10376-86 : DOI : 10.1093/nar/gkv1167 En savoir plus
Résumé

Thermodynamic studies of ligand binding to human telomere (ht) DNA quadruplexes, as a rule, neglect the involvement of various ht-DNA conformations in the binding process. Therefore, the thermodynamic driving forces and the mechanisms of ht-DNA G-quadruplex-ligand recognition remain poorly understood. In this work we characterize thermodynamically and structurally binding of netropsin (Net), dibenzotetraaza[14]annulene derivatives (DP77, DP78), cationic porphyrin (TMPyP4) and two bisquinolinium ligands (Phen-DC3, 360A-Br) to the ht-DNA fragment (Tel22) AGGG(TTAGGG)3 using isothermal titration calorimetry, CD and fluorescence spectroscopy, gel electrophoresis and molecular modeling. By global thermodynamic analysis of experimental data we show that the driving forces characterized by contributions of specific interactions, changes in solvation and conformation differ significantly for binding of ligands with low quadruplex selectivity over duplexes (Net, DP77, DP78, TMPyP4; KTel22 ≈ <KdsDNA) and for highly selective quadruplex-specific ligands (Phen-DC3, 360A-Br; KTel22 > KdsDNA). These contributions are in accordance with the observed structural features (changes) and suggest that upon binding Net, DP77, DP78 and TMPyP4 select hybrid-1 and/or hybrid-2 conformation while Phen-DC3 and 360A-Br induce the transition of hybrid-1 and hybrid-2 to the structure with characteristics of antiparallel or hybrid-3 type conformation.

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Patrick Merle, Marine Gueugneau, Marie-Paule Teulade-Fichou, Mélanie Müller-Barthélémy, Simon Amiard, Emmanuel Chautard, Corinne Guetta, Véronique Dedieu, Yves Communal, Jean-Louis Mergny, Maria Gallego, Charles White, Pierre Verrelle, Andreï Tchirkov (2015 Nov 7)

Highly efficient radiosensitization of human glioblastoma and lung cancer cells by a G-quadruplex DNA binding compound.

Scientific reports : 5 : 16255 : DOI : 10.1038/srep16255 En savoir plus
Résumé

Telomeres are nucleoprotein structures at the end of chromosomes which stabilize and protect them from nucleotidic degradation and end-to-end fusions. The G-rich telomeric single-stranded DNA overhang can adopt a four-stranded G-quadruplex DNA structure (G4). Stabilization of the G4 structure by binding of small molecule ligands enhances radiosensitivity of tumor cells, and this combined treatment represents a novel anticancer approach. We studied the effect of the platinum-derived G4-ligand, Pt-ctpy, in association with radiation on human glioblastoma (SF763 and SF767) and non-small cell lung cancer (A549 and H1299) cells in vitro and in vivo. Treatments with submicromolar concentrations of Pt-ctpy inhibited tumor proliferation in vitro with cell cycle alterations and induction of apoptosis. Non-toxic concentrations of the ligand were then combined with ionizing radiation. Pt-ctpy radiosensitized all cell lines with dose-enhancement factors between 1.32 and 1.77. The combined treatment led to increased DNA breaks. Furthermore, a significant radiosensitizing effect of Pt-ctpy in mice xenografted with glioblastoma SF763 cells was shown by delayed tumor growth and improved survival. Pt-ctpy can act in synergy with radiation for efficient killing of cancer cells at concentrations at which it has no obvious toxicity per se, opening perspectives for future therapeutic applications.

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R Chennoufi, H Bougherara, N Gagey-Eilstein, B Dumat, E Henry, F Subra, F Mahuteau-Betzer, P Tauc, M-P Teulade-Fichou, E Deprez (2015 Oct 15)

Differential behaviour of cationic triphenylamine derivatives in fixed and living cells: triggering and imaging cell death.

Chemical communications (Cambridge, England) : 51 : 14881-14884 : DOI : 10.1039/c5cc05970d En savoir plus
Résumé

Triphenylamines are on/off fluorescent DNA minor groove binders, allowing nuclear staining of fixed cells. By contrast, they accumulate in the cytoplasm of living cells and efficiently trigger cell apoptosis upon prolonged visible light irradiation. This process occurs concomitantly with their subcellular re-localization to the nucleus, enabling fluorescence imaging of apoptosis.


Differential_behaviour

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