Études multiparamétriques de biomarqueurs par immunofluorescence pour mieux suivre la progression du cancer de la prostate

Le cancer de la prostate est le cancer le plus fréquemment diagnostiqué et la troisième cause de mortalité liée au cancer chez les hommes au Canada. Un quart des patients diagnostiqués développeront une forme plus agressive de ce cancer. Bien que nous possédions plusieurs indices cliniques pronostiques dans les cancers localisés (score de Gleason, taux sérique d’antigène prostatique spécifique (APS), stade, etc.), ceux-ci sont insuffisants pour adéquatement distinguer les patients à faible risque de progression de ceux à haut risque. A ce jour, aucun biomarqueur pronostique n’est encore utilisé en clinique. Les cliniciens ont donc besoin de nouveaux outils plus efficaces pour stratifier ce cancer et pour s’assurer d’adapter au mieux le traitement à chaque patient. En nous basant sur la littérature et sur des études préliminaires (cohortes de moins de 65 patients), notre hypothèse est que les protéines PUMA-NOXA et les récepteurs membranaires de la famille ERBB seraient, lorsqu’utilisés en combinaison, des biomarqueurs prédictifs de la progression du cancer de la prostate. Les objectifs de cette thèse sont : 1) identifier et valider de bons anticorps pour chaque biomarqueur d’intérêt, 2) définir les niveaux d’expression de chaque biomarqueur sur une cohorte de 285 patients, et 3) établir les corrélations entre les niveaux d’expression et les données cliniques des patients. Dans l’optique d’une utilisation en clinique, des anticorps de type monoclonal ont été choisis pour identifier les biomarqueurs d’intérêts. Ces anticorps ont été testés et validés pour leur spécificité par immunobuvardage de type western blot et par immunofluorescence. La localisation de la protéine d’intérêt a été validée sur des échantillons de tissus de patients suivie de l’optimisation du multi-marquage sur les cellules épithéliales et basales. Après perfectionnement de l’analyse d’images, nous avons montré qu’une expression extrême (faible ou forte) de PUMA couplée à une forte expression de NOXA dans les glandes bénignes est associée à la rechute biochimique des patients. La présence de ces biomarqueurs dans les glandes bénignes permet d’envisager d’améliorer l’identification lors des premières biopsies des patients se qualifiant pour la surveillance active. Par ailleurs, le suivi de l’expression des récepteurs de la famille ERBB dans les glandes tumorales permet une stratification des patients atteints d’un cancer de la prostate en fonction des risques de rechute biochimique, de développement de métastases et de mort liée au cancer. Ainsi, les patients présentant la combinaison d’une forte expression de EGFR et d’une faible expression de ERBB3 sont les plus susceptibles de mourir spécifiquement de leur cancer de la prostate, en particulier si les cellules tumorales présentes en plus une faible expression de ERBB2 entrainant un fort risque de développer des métastases. Mon projet de doctorat aura donc permis d’identifier et de valider des biomarqueurs d’intérêt pour prédire l’évolution du cancer de la prostate et démontrer l’intérêt de suivre ces biomarqueurs en combinaison afin d’obtenir une meilleure stratification des patients. Ces résultats devront être validés sur une cohorte indépendante et multicentrique en vue de fournir aux cliniciens un plus grand nombre d’outils pour leur permettre de réaliser une stratification fine des patients atteints d’un cancer de la prostate, et ouvrirait la voie à de nouvelles stratégies thérapeutiques plus ciblées.Prostate cancer is the most frequently diagnosed cancer and the third leading cause of cancer-related death in men in Canada. A quarter of patients will develop a more aggressive form of this cancer. While there are several clinical prognostic variables for localized prostate cancer (Gleason score, prostate specific antigen (PSA) levels, stage, etc.), these are insufficient to adequately distinguish between low and high-risk of progression cases. As a result, clinicians need new, more effective tools to stratify this cancer and to ensure that treatments are best tailored to each patient. To date, no prognostic biomarker has yet been used clinically. Based on the literature and preliminary studies of small cohorts (less than 65 patients), we hypothesize that the protein expression of PUMA-NOXA and ERBB family members could help with the prediction of prostate cancer progression. The objectives of this thesis are: 1) to identify and validate antibodies for each biomarker of interest, 2) to define the expression levels of each biomarker on a 285 patient cohort, 3) to evaluate the correlation between marker expression levels and patient clinical data. For clinical use, monoclonal-type antibodies were chosen to identify the biomarkers of interest. These antibodies were validated for specificity by western blot and immunofluorescence techniques. The localization of the protein of interest was further identified within samples of patient tissues and additional optimization involving combinatorial staining for epithelial and basal cells. After refining the imaging and statistical analysis of PUMA and NOXA in benign glands, we found that extreme (weak or strong) PUMA expression coupled with high NOXA expression was associated with biochemical relapse. In addition, these proteins have significant potential for predicting disease evolution based on the initial radical prostatectomy sample. The presence of these proteins in benign glands would allow the identification of patients less suitable for active surveillance. Additionally, statistical analysis of ERBB family receptors in tumor glands, when used alone, allow stratification of prostate cancer patients for the prediction of biochemical relapse, development of metastases and also specific death from prostate cancer. Moreover, patients expressing a combination of high EGFR expression and low ERBB3 expression are at high risk of biochemical relapse and are at higher risk of prostate cancer specific mortality. In addition, coupling this high EGFR – low ERBB3 combination to a low ERBB2 expression helps classify patients at high risk of developing metastases. My doctoral research project will have made it possible to identify and validate biomarkers of interest for predicting the progression of prostate cancer and demonstrating the interest of combining these biomarkers in order to achieve better stratification of patients with prostate cancer. In the context of clinical utility, these results need to be validated on an independent and multicenter cohort in order to confirm these findings. This would eventually provide clinicians with a greater number of tools at their disposal to correctly anticipate patient trajectories and possibly identify new therapeutic targets for the control of the disease

Descriptors of Posidonia oceanica meadows: Use and application

The conservation of the coastal marine environment requires the possession of information that enables the global quality of the environment to be evaluated reliably and relatively quickly. The use of biological indicators is often an appropriate method. Seagrasses in general, and Posidonia oceanica meadows in particular, are considered to be appropriate for biomonitoring because of their wide distribution, reasonable size, sedentary habit, easy collection and abundance and sensitivity to modifications of littoral zone. Reasoned management, on the scale of the whole Mediterranean basin, requires standardized methods of study, to be applied by both researchers and administrators, enabling comparable results to be obtained. This paper synthesises the existing methods applied to monitor P. oceanica meadows, identifies the most suitable techniques and suggests future research directions. From the results of a questionnaire, distributed to all the identified laboratories working on this topic, a list of the most commonly used descriptors was drawn up, together with the related research techniques (e.g. standardization, interest and limits, valuation of the results). It seems that the techniques used to study meadows are rather similar, but rarely identical, even though the various teams often refer to previously published works. This paper shows the interest of a practical guide that describes, in a standardized way, the most useful techniques enabling P. oceanica meadows to be used as an environmental descriptor. Indeed, it constitutes the first stage in the process. (c) 2005 Elsevier Ltd. All rights reserved.Peer reviewe

Etapes initiales de l'infection par le VIH (nouveaux développements thérapeutiques)

CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

B. - Les Foraminifères/ Foraminifera

The study of the Foraminifera found in surface sediments (dredging and cores tops) point out the specific diversity of the populations. The assemblages corresponding to the various kinds of environments are described and mapped. The cores show the paleoceanographical and paleoecological evolution during the last 30 000 years.L'étude des Foraminifères trouvés dans les sédiments de surface (dragages et sommets de carottes) met en évidence la diversité spécifique des peuplements. Les assemblages correspondant à divers environnements sont décrits et cartographiés. Les carottes montrent l'évolution paléocéanographique et paléoécologique de cette région depuis 30 000 ans.Blanc-Vernet Laure, Clairefond Pierre, Orsolini Patrick, Templeton R.S.M., Desprat R. B. - Les Foraminifères/ Foraminifera. In: Géologie Méditerranéenne. Tome 6, numéro 1, 1979. La mer pélagienne. Etude sédimentologique et écologique du Plateau tunisien et du Golfe de Gabès. pp. 171-209

A. -Morphologie/ Morphology

Blanpied Christian, Burollet Pierre-Félix, Clairefond Pierre, Shimi Mohamed, Templeton R.S.M., Desprat R. A. -Morphologie/ Morphology. In: Géologie Méditerranéenne. Tome 6, numéro 1, 1979. La mer pélagienne. Etude sédimentologique et écologique du Plateau tunisien et du Golfe de Gabès. pp. 19-22

III - Sédiments actuels et holocènes / Present and holocene sediments

In the Pelagian Sea the sediments may be classified in four categories : -detritic quartzose sand along the shores ; -bioclastic sands : carbonate production is related to Phanéro¬ game meadows between 0 and 25 meters of water depth, Caulerpa meadows between 25 and 45 m, and Vidalia association between 45 and 100 m ; -carbonate mud in hollows of the Plateau or in the central part of the Gulf of Gabes ; -more clayey mud in slopes and troughs. Gammadensimetry measurements and X-ray examinations indicated a stratification in relation with the end of Wiirm III and with the versilian transgression. These deep sediments contain also turbiditic layers and volcano-clastic elements.Les sédiments de la Mer Pélagienne sont de quatre catégories : -sables détritiques quartzeux le long des côtes ; -sables bioclastiques liés à la production de carbonate associée aux herbiers à Phanérogames entre 0 et 25 mètres, aux pelouses à Caulerpes entre 25 et 45 mètres et à Vidalia entre 45 et 100 mètres ; -vases carbonatées dans les dépressions du plateau ou du Golfe de Gabès ; -vases plus argileuses dans les fosses et le long de talus-, les mesures de gammadensimètrie et des examens aux rayons " X " ont montré une stratification liée à la fin du Wiirm III et à la transgression versilienne. On y connaît en outre des passées turbiditiques et volcano-sédimentaires.Blanpied Christian, Burollet Pierre-Félix, Clairefond Pierre, Shimi Mohamed, Templeton R.S.M., Desprat R. III - Sédiments actuels et holocènes / Present and holocene sediments. In: Géologie Méditerranéenne. Tome 6, numéro 1, 1979. La mer pélagienne. Etude sédimentologique et écologique du Plateau tunisien et du Golfe de Gabès. pp. 61-82

Synthesis and characterization of sodium hafnium oxide (Na2HfO3) and its high-temperature CO2 sorption properties

The CO2 sorption properties of sodium hafnium oxide (Na2HfO3) were investigated in this study. Na2HfO3 was synthesized by solid-state synthesis using Na2CO3 and HfO2 as starting materials. The solid-state synthesized Na2HfO3 appeared structurally similar to other mixed metal oxides such as Na2ZrO3, but stacking disorder appeared to be common in Na2HfO3. The synthesis conditions, including the Na : Hf ratio (between 0.5 and 1.5 : 1), synthesis temperature, time and heating rate, were investigated to optimize CO2 sorption properties of Na2HfO3. The Na2HfO3 sorbent showed comparable CO2 uptake capacity, reaction rate and excellent cycling stability compared to other metal oxide sorbents. Na2HfO3 with Na : Hf = 1 : 1 and 1.25 : 1 showed the highest CO2 uptake among all Na2HfO3 samples obtained, with a CO2 uptake capacity of around 15 wt% (at 650–800 °C). The CO2 uptake rate of NHO-1 and NHO-1.25 was fast with over 80% of the equilibrium uptake reached within 250 s. Na2HfO3 remained stable even after 100 cycles with less than 3% difference in the CO2 uptake capacity between the 1st and 100th cycles. We performed kinetic analysis on the CO2 sorption data and found that the Avrami–Erofeev model fitted the kinetic data best among the kinetic models used. Apart from sorbent optimization, we showed that 3D-printing of Na2HfO3 : HfO2 mixtures can be used to produce structured Na2HfO3 sorbents with a slightly improved CO2 uptake rate and the same CO2 uptake capacity as the powder-based solid-state synthesized Na2HfO3 sorbent

Myocilin expression is regulated by retinoic acid in the trabecular meshwork-derived cellular environment

International audienceGlaucoma is the leading cause of irreversible blindness and is usually classified as angle closure and open angle glaucoma (OAG). Primary open angle glaucoma represents the most frequent clinical presentation leading to ganglion cell death and optic nerve degeneration as a main consequence of an intraocular pressure' (IOP) increase. The mechanisms of this IOP increase in such pathology remain unclear but one protein called Myocilin could be a part of the puzzle in the trabecular meshwork (TM). Previously described to be transcriptionally regulated by glucocorticoids, the comprehension of the trabecular regulation of Myocilin' expression has only weakly progressed since 15 years. Due to the essential molecular and cellular implications of retinoids' pathway in eye development and physiology, we investigate the potential role of the retinoic acid in such regulation and expression. This study demonstrates that the global retinoids signaling machinery is present in immortalized TM cells and that Myocilin (MYOC) expression is upregulated by retinoic acid alone or combined with a glucocorticoid co-treatment. This regulation by retinoic acid acts through the MYOC promoter which contains a critical cluster of four retinoic acid responsive elements (RAREs), with the RARE-DR2 presenting the strongest effect and binding the RARα/RXRα heterodimer. All together, these results open up new perspectives for the molecular understanding glaucoma pathophysiology and provide further actionable clues on Myocilin gene regulation

All-trans retinoic acid promotes wound healing of primary amniocytes through the induction of LOXL4, a member of the lysyl oxidase family

International audienceThirty percent of preterm births directly result from preterm premature rupture of fetal membranes (PPROM). Clinical management currently proposes using a collagen plug to mechanically stop loss of amniotic fluid. Vitamin A and its active metabolite (retinoic acid) have well-known pro-healing properties and could thus make good candidates as a proposable adjuvant to this mechanical approach. Here we investigate the molecular mechanisms involved in the pro-healing properties of all-trans retinoic acid (atRA) in fetal membranes via an approach using an in vitro primary amniocyte wound model and transcriptomics. The results demonstrate that atRA promotes migration in primary amniocytes, improving wound healing in vitro by up to 90%. This effect is mediated by the induction of LOXL4, which plays a crucial role in the dynamics of the extracellular matrix by regulating collagen reticulation. This new insight into how atRA exerts its pro-healing properties prompts us to propose using atRA as a candidate strategy to help prevent future PPROM