Éditeur(s) : HAL CCSD Cancer Research UK
Résumé : International audience
BACKGROUND: Cancer cell killing might be achieved by the combined use of available drugs. Statins are major anti-hypercholesterolemia drugs, which also trigger apoptosis of many cancer cell types, while docetaxel is a potent microtubule-stabilising agent. METHODS: Here, we looked at the combined effects of lovastatin and docetaxel in cancer cells. RESULTS: Whole transcriptome microarrays in HGT-1 gastric cancer cells demonstrated that lovastatin strongly suppressed expression of genes involved in cell division, while docetaxel had very little transcriptional effects. Both drugs triggered apoptosis, and their combination was more than additive. A marked rise in the cell-cycle inhibitor p21, together with reduction of aurora kinases A and B, cyclins B1 and D1 proteins was induced by lovastatin alone or in combination with docetaxel. The drug treatments induced the proteolytic cleavage of procaspase-3, a drop of the anti-apoptotic Mcl-1 protein, Poly-ADP-Ribose Polymerase and Bax. Strikingly, docetaxel-resistant HGT-1 cell derivatives overexpressing the MDR-1 gene were much more sensitive to lovastatin than docetaxel-sensitive cells. CONCLUSION: These results suggest that the association of lovastatin and docetaxel, or lovastatin alone, shows promise as plausible anticancer strategies, either as a direct therapeutic approach or following acquired P-glycoprotein-dependent resistance.
ISSN: 0007-0920

hal-00684528
https://hal.archives-ouvertes.fr/hal-00684528
DOI : 10.1038/bjc.2012.6
PUBMED : 22294184

Éditeur(s) : HAL CCSD SAGE Publications (UK and US)
Résumé : International audience
Enamel and enameloid, the highly mineralized tooth-covering tissues in living vertebrates, are different in their matrix composition. Enamel, a unique product of ameloblasts, principally contains enamel matrix proteins (EMPs), while enameloid possesses collagen fibrils and probably receives contributions from both odontoblasts and ameloblasts. Here we focused on type I collagen (COL1A1) and amelogenin (AMEL) gene expression during enameloid and enamel formation throughout ontogeny in the caudate amphibian, Pleurodeles waltl. In this model, pre-metamorphic teeth possess enameloid and enamel, while post-metamorphic teeth possess enamel only. In first-generation teeth, qPCR and in situ hybridization (ISH) on sections revealed that ameloblasts weakly expressed AMEL during late-stage enameloid formation, while expression strongly increased during enamel deposition. Using ISH, we identified COL1A1 transcripts in ameloblasts and odontoblasts during enameloid formation. COL1A1 expression in ameloblasts gradually decreased and was no longer detected after metamorphosis. The transition from enameloid-rich to enamel-rich teeth could be related to a switch in ameloblast activity from COL1A1 to AMEL synthesis. P. waltl therefore appears to be an appropriate animal model for the study of the processes involved during enameloid-to-enamel transition, especially because similar events probably occurred in various lineages during vertebrate evolution.
ISSN: 0022-0345

hal-01545475
https://hal.archives-ouvertes.fr/hal-01545475
DOI : 10.1177/0022034514526236

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: The orphan receptors COUP-TF (chicken ovalbumin upstream promoter transcription factor) I and II are members of the nuclear receptor superfamily that play distinct and critical roles in vertebrate organogenesis. The involvement of COUP-TFs in cancer development has recently been suggested by several studies but remains poorly understood. METHODS: MCF-7 breast cancer cells overexpressing COUP-TFI and human breast tumors were used to investigate the role of COUP-TFI in the regulation of CXCL12/CXCR4 signaling axis in relation to cell growth and migration. We used Immunofluorescence, western-blot, RT-PCR, Formaldehyde-assisted Isolation of Regulatory Elements (FAIRE) assays, as well as cell proliferation and migration assays. RESULTS: Previously, we showed that COUP-TFI expression is enhanced in breast cancer compared to normal tissue. Here, we report that the CXCL12/CXCR4 signaling pathway, a crucial pathway in cell growth and migration, is an endogenous target of COUP-TFI in breast cancer cells. The overexpression of COUP-TFI in MCF-7 cells inhibits the expression of the chemokine CXCL12 and markedly enhances the expression of its receptor, CXCR4. Our results demonstrate that the modification of CXCL12/CXCR4 expression by COUP-TFI is mediated by the activation of epithelial growth factor (EGF) and the EGF receptor. Furthermore, we provide evidence that these effects of COUP-TFI increase the growth and motility of MCF-7 cells in response to CXCL12. Cell migration toward a CXCL12 gradient was inhibited by AMD3100, a specific antagonist of CXCR4, or in the presence of excess CXCL12 in the cell culture medium. The expression profiles of CXCR4, CXCR7, CXCL12, and COUP-TFI mRNA in 82 breast tumors and control non-tumor samples were measured using real-time PCR. CXCR4 expression was found to be significantly increased in the tumors and correlated with the tumor grade, whereas the expression of CXCL12 was significantly decreased in the tumors compared with the healthy samples. Significantly higher COUP-TFI mRNA expression was also detected in grade 1 tumors. CONCLUSIONS: Together, our mechanistic in vitro assays and in vivo results suggest that a reduction in chemokine CXCL12 expression, with an enhancement of CXCR4 expression, provoked by COUP-TFI, could be associated with an increase in the invasive potential of breast cancer cells.
ISSN: 1471-2407

hal-01024753
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01024753/file/1471-2407-14-407.pdf
DOI : 10.1186/1471-2407-14-407

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, has emerged as an active mediator in many essential functions in the central nervous system of mammals. BDNF plays significant roles in neurogenesis, neuronal maturation and/or synaptic plasticity and is involved in cognitive functions such as learning and memory. Despite the vast literature present in mammals, studies devoted to BDNF in the brain of other animal models are scarse. Zebrafish is a teleost fish widely known for developmental genetic studies and is emerging as model for translational neuroscience research. In addition, its brain shows many sites of adult neurogenesis allowing higher regenerative properties after traumatic injuries. To add further knowledge on neurotrophic factors in vertebrate brain models, we decided to determine the distribution of bdnf mRNAs in the larval and adult zebrafish brain and to characterize the phenotype of cells expressing bdnf mRNAs by means of double staining studies. Our results showed that bdnf mRNAs were widely expressed in the brain of 7 days old larvae and throughout the whole brain of mature female and male zebrafish. In adults, bdnf mRNAs were mainly observed in the dorsal telencephalon, preoptic area, dorsal thalamus, posterior tuberculum, hypothalamus, synencephalon, optic tectum and medulla oblongata. By combining immunohistochemistry with in situ hybridization, we showed that bdnf mRNAs were never expressed by radial glial cells or proliferating cells. By contrast, bdnf transcripts were expressed in cells with neuronal phenotype in all brain regions investigated. Our results provide the first demonstration that the brain of zebrafish expresses bdnf mRNAs in neurons and open new fields of research on the role of the BDNF factor in brain mechanisms in normal and brain repairs situations.
ISSN: 1932-6203

hal-01359562
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359562
DOI : 10.1371/journal.pone.0158057
PUBMED : 27336917

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The estrogen receptor (ER) is a transcription factor that binds under 17-b-estradiol (E2) stimulation as homodimer to a short DNA consensus sequence named estrogen response element (ERE). The ER/ERE interaction has been assessed by several research groups through different methodologies notably by surface plasmon resonance (SPR) techniques. The biochemical parameters and conditions (solvent, ER concentration, salt, time and temperature) used to prepare samples before analysis were very different from one study to another. But no studies have aimed to compare the effect of these modifications on ER/ERE interaction. Therefore the main objective of the present paper was to assess the influence of biochemical parameters onto the ER/ERE interaction with the final aim to improve the comprehension of this interaction. Our results highlighted that parameters like solvent, ER concentration, salt and surfactant concentration, temperature and time deeply modify ER/ERE interaction. Nevertheless, the dimer formation under E2 stimulation occurred with all tested conditions. Altogether, incubation parameters of ER with E2, deeply modify its binding level onto ERE. These data constitute an important key point to consider for the improvement of ER/ERE detection method depending upon the aim of the study (interaction measurement, environmental detection, development of new technologies or devices).
ISSN: 0003-9861

hal-00936061
https://hal.archives-ouvertes.fr/hal-00936061
https://hal.archives-ouvertes.fr/hal-00936061/document
https://hal.archives-ouvertes.fr/hal-00936061/file/Impactsur biochemical_design_on_estrogen_receptor_estrogen_response_element_interaction_by_surface_plasmon_resonance_technology-accepted.pdf
DOI : 10.1016/j.abb.2013.11.006

Éditeur(s) : HAL CCSD
Résumé : Anti-Müllerian hormone (AMH) is a member of the TGF-ß superfamily. AMH is well known for its role in Müllerian duct regression in male fetuses. Postnatally, AMH is secreted by granulosa cells (GCs) of small growing follicles (preantral and small antral). However, despite the increasing interest of ovarian AMH in clinics, little is known on its mechanism of action and its role in female reproductive tract. My PhD project focuses on the identification of AMH function in the female reproductive tract.AMH signals through a type II transmembrane serine/threonine kinase receptor (AMHR-II) which forms a complex with a type I serine/threonine kinase receptor (ActR-IA, BMPR-IA, BMPR-IB). The type II receptor phosphorylates serine and threonine residues of type I receptor. Once activated, the type I receptor phosphorylates the receptor-regulated Smads (R-Smad1/5/8) which interact with a common partner Smad4. The Smad complex accumulates into the nucleus and regulates target gene expression. This canonical signalling pathway is regulated at different levels, in particular by co-receptors which amplify or antagonize TGF-ß family members action. The type I receptors and R-Smads involved in AMH effects on post-natal GCs remain unknown. In addition, to date, no co-receptor has been found for AMH. To define the involvement of the different type I receptors, we used siRNA technology to inactivate Acvr1, Bmpr1a and Bmpr1b in GC. In parallele, we analysed GC extracted from conditional mutant mice for Acvr1 and Bmpr1a. We found that BMPR-IA is the most important type I receptor for AMH to transduce its signal in GC. A Smad-Gal4/UAS-luciferase reporter gene technology allowed us to show that Smad1 and 5 are involved in AMH signaling pathway. Recently, new BMPs coreceptors were found, RGMs for Repulsive Guidance Molecules. There are three RGMs : RGMa, b and c. Because AMH shares with BMPs its type I receptors and R-Smad proteins, we hypothesized that they also share the same co-receptors, the RGM. We showed that RGMb was the only one expressed in GC and after siRNA transfection we demonstrated that this coreceptor is not essential for AMH to transduce its signal.To date, only few AMH target genes have been identified. Aromatase (Cyp19a1) and LH receptor (Lhcgr) are down-regulated by AMH in rat and porcine GCs. We used micro-array technology (Affymetrix) by comparing Wt and knockout immature ovaries to find new AMH target genes. This experiment evidenced that Ovgp1 and Kcnj2 are two new potential AMH target genes in the ovary.The last part of my project was to define a potential role of AMH in murine uterus. Only one study showed that AMHR-II is expressed in the mouse myometrium. We showed that Amh gene is slightly expressed in uterus but the results are not confirmed at the protein level. Using PCR-array, we found a lot of differentially expressed genes between Wt and Amh KO uterus. Therefore, AMH could regulate uterine function through the modulation of different genes located in the myometrium.
L’hormone anti-Müllerienne (AMH) est un membre de la famille TGF-β impliquée dans la différenciation du tractus reproductif mâle. Elle est aussi exprimée par les cellules de la granulosa de l’ovaire adulte. Cependant, son rôle physiologique chez la femelle n’a pas encore été entièrement établi. Mon projet de thèse a pour objectif d’élucider le(s) rôle(s) de l’AMH dans le tractus reproductif femelle. L’AMH transduit ses effets par l’intermédiaire de deux récepteurs transmembranaires sérine/thréonine kinase : un récepteur de type II qui lui est spécifique (AMHR-II) et un récepteur de type I (ActR-IA, BMPR-IA, BMPR-IB) qu’elle partage avec les BMPs. Après fixation de l’hormone sur le récepteur de type II, celui-ci recrute et phosphoryle le récepteur de type I. Ce dernier phosphoryle à son tour les Smads spécifiques (Smad1, 5 et 8) qui s’associent à la Smad commune, Smad4. L’ensemble transloque dans le noyau et en association avec des facteurs de transcription régule les gènes cibles de l’hormone. L'utilisation de souris KO conditionnelles pour les récepteurs Acvr1 et Bmpr1a et d'une technique de siRNA dirigés contre chacun des trois récepteurs de type I a permis de mettre en évidence que le récepteur BMPR-IA est un acteur essentiel de la voie de signalisation de l'AMH dans les cellules de la granulosa. Pour déterminer la ou les Smad(s) impliquées, une technique de gènes rapporteurs, Smad-Gal4/UAS-luciférase, a été utilisée. Nous avons pu montrer que les Smad1 et 5 sont importantes pour la transduction du signal de l'AMH dans les cellules de la granulosa. Récemment des corécepteurs aux BMPs, les Repulsive Guidance Molecule (RGMs), ont été mis en évidence. L’AMH partageant sa voie de signalisation avec les BMPs, nous avons cherché à déterminer si ces corécepteurs pouvaient également intervenir dans la voie de signalisation de l’AMH. Il existe 3 types de RGMs: RGMa, RGMb et RGMc. Nous avons montré en q-PCR que seul RGMb est exprimé dans les cellules de la granulosa alors que les 3 RGMs sont exprimés dans l’ovaire. L'utilisation de siRNA dirigés contre RGMb a permis de montrer que ce récepteur n'est pas nécessaire à la transduction du signal de l'AMH. Actuellement, seuls deux gènes cibles de l’AMH sont connus dans les cellules de la granulosa : l’aromatase et le récepteur LH. Nous avons réalisé des analyses de puces à ADN (ou micro-array) pour décrire de nouveaux gènes cibles de l'AMH. L'analyse des puces a permis de décrire de nouveaux gènes régulés par cette hormone tels qu’Ovgp1 ou Kcnj2. La dernière partie de mon projet visait à déterminer un rôle potentiel de l'AMH dans l'utérus. En effet, le récepteur de cette hormone est exprimé dans le myomètre utérin de souris permettant de supposer qu’elle peut agir sur cet organe. Nous avons pu mettre en évidence une expression faible du gène de l’Amh dans l’utérus. En revanche, l’expression et la localisation de la protéine restent encore à définir. Une expérience de PCR-array a permis de montrer que de nombreux gènes sont différentiellement exprimés entre l’utérus Wt et l’utérus KO Amh. Ceci indique que l’AMH jouerait un rôle sur la régulation de la fonction utérine qu’elle soit exprimée ou non dans cet organe.
https://tel.archives-ouvertes.fr/tel-00989662

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2014PA11T014
tel-00989662
https://tel.archives-ouvertes.fr/tel-00989662
https://tel.archives-ouvertes.fr/tel-00989662/document
https://tel.archives-ouvertes.fr/tel-00989662/file/VA_SEDES_LAURIANE_03042014.pdf

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
Stem cells are pivotal for development and tissue homeostasis of multicellular animals, and the quest for a gene toolkit associated with the emergence of stem cells in a common ancestor of all metazoans remains a major challenge for evolutionary biology. We reconstructed the conserved gene repertoire of animal stem cells by transcriptomic profiling of totipotent archeocytes in the demosponge Ephydatia fluviatilis and by tracing shared molecular signatures with flatworm and Hydra stem cells. Phylostratigraphy analyses indicated that most of these stem-cell genes predate animal origin, with only few metazoan innovations, notably including several partners of the Piwi machinery known to promote genome stability. The ancestral stem-cell transcriptome is strikingly poor in transcription factors. Instead, it is rich in RNA regulatory actors, including components of the ``germ-line multipotency program'' and many RNA-binding proteins known as critical regulators of mammalian embryonic stem cells.
ISSN: 0027-8424

hal-01544480
https://hal.archives-ouvertes.fr/hal-01544480
DOI : 10.1073/pnas.1514789112

Résumé : L’HTLV-1 est l’agent étiologique de la TSP/HAM et de l’ATL. La TSP/HAM est une méningomyélite chronique d’évolution lente et progressive. La charge provirale HTLV-1 est corrélée à l’évolutivité de la maladie. La protéine virale Tax module la synthèse et la fonction de multiples protéines de la prolifération et de la survie des lymphocytes T infectés. L’expression virale n’est pas toujours détectable in vivo. Une modulation épigénétique par inhibiteurs d’HDAC a été proposée. Des travaux dans le modèle du BLV et in vitro dans l’infection à HTLV-1 ont conforté ce concept et conduit à un essai thérapeutique évaluant le VPA dans le traitement de la TSP/HAM, qui n’a pas montré d’impact sur la charge provirale. Nous nous sommes intéressés à l’effet du VPA sur les lymphocytes T CD4+ en culture, cibles du virus HTLV-1. L’expression du génome viral, surtout la balance entre les protéines Tax et HBZ a été étudiée avec ou sans VPA. Son expression serait corrélée à la charge provirale et à l’évolution de la TSP/HAM. Nous montrons qu’un tiers des cellules CD4+ infectées expriment Tax. Cette proportion augmente sous VPA. La détection de la protéine p19 est augmentée sous VPA. La stimulation par le VPA de la transcription sens du génome viral a été confirmée par quantification des messagers Tax et Gag alors que l’expression d’HBZ se trouve réprimée sous VPA. Les données cinétiques d’expression spontanée d’HBZ montrent l’existence d’un rétrocontrôle négatif exercé par HBZ sur l’expression de Tax et des gènes structuraux. Influer sur l’expression d’HBZ ouvre une voie nouvelle pour le traitement des maladies associées à HTLV-1.
HTLV-1 is the etiological agent of HAM/TSP and ATL. TSP/HAM is a chronic meningomyelitis with a course being slow and progressive. HTLV-1 proviral load correlates with disease progression. Tax protein modulates the synthesis and function of proteins involved in the regulation of infected T-lymphocytes proliferation and survival. Viral expression is not always detectable in vivo. An epigenetic modulation by the use of HDAC inhibitors has been proposed. A study in the BLV model and an in vitro study in a HTLV-1 infection have lead to a therapeutic assay in order to assess VPA in the treatment of HAM/TSP. This assay did not show any impact on the proviral load. We evaluated the impact of VPA treatment on viral genome expression in cultured lymphocytes, especially the balance between Tax and HBZ. A third of provirus-positive CD4+ T cells spontaneously became Tax-positive. The estimation rose up to two-thirds of Tax-positive infected cells when VPA was added. VPA enhanced Gag p19 protein release. VPA treatment enhanced and prolonged Tax mRNA expression, while it blocked HBZ expression. Our data are consistent with the hypothesis of a feed-back loop coordinating Tax and HBZ expression. Modulation of HBZ expression may impact the net outcome of VPA treatment on HTLV-1-infected cell proliferation and survival.

http://www.theses.fr/2011AGUY0403

Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
: Estradiol signaling is ideally suited for analyzing molecular and functional linkages between the different layers of information directing transcriptional regulations: DNA sequence, chromatin modifications and the spatial organization of the genome. Hence, estrogen receptor (ER) can bind at a distance from its target genes and engages timely and spatially coordinated processes to regulate their expression. In the context of the coordinated regulations of co-linear genes, identifying which ER binding sites (ERBSs) regulate a given gene still remains a challenging question. Here, we investigated the coordination of such regulatory events at a 2 Mb genomic locus containing the estrogen-sensitive TFF cluster of genes in breast cancer cells. We demonstrated that this locus exhibits a hormone and cohesin-dependent reduction in the plasticity of its three-dimensional organization that allows multiple ERBSs to be dynamically brought to the vicinity of estrogen-sensitive genes. Additionally, by using triplex forming oligonucleotides, we could precisely document the functional links between ER engagement at given ERBSs and the regulation of particular genes. Hence, our data evidence a formerly suggested cooperation of enhancers towards gene regulations, and also show that redundancy between ERBSs can occur.
ISSN: 0270-7306

hal-00984591
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00984591
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00984591/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00984591/file/Mol._Cell._Biol.-2014-Quintin-MCB.00918-13.pdf
DOI : 10.1128/MCB.00918-13

Éditeur(s) : Paris : Imprimerie J.-A. Boudon
Extrait de : Extrait de la revue des colonies
Résumé : Rapport de l'audiance du tribunal avec transcription de l'article ayant donné lieu au procès
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Fondation Clément
Permalien : http://www.manioc.org/patrimon/FCL15005
FCL15005