Renversement des hétérogénéités spatiale et temporelle de la perfusion tumorale identifie la tumeur tonus vasculaire comme une variable ajustable pour améliorer la prestation de drogue

peer reviewedMaturation de la vascularisation tumorale implique le recrutement de péricytes qui protègent les tubes endothéliales provenant de diverses contraintes, y compris les médicaments anti-angiogéniques. Mural cells also provide mature tumor blood vessels with the ability to either relax or contract in response to substances present in the tumor microenvironment. cellules murale également fournir d'âge mûr vaisseaux sanguins des tumeurs avec la possibilité de détendre ou se contracter en réponse à des substances présentes dans le microenvironnement de la tumeur. The observed cyclic alterations in tumor blood flow and the associated deficit in chemotherapeutic drug delivery could in part arise from this vasomodulatory influence. To test this hypothesis, we focused on endothelin-1 (ET-1), which, besides its autocrine effects on tumor cell growth, is a powerful vasoconstrictor. Les cycliques altérations observées dans la circulation sanguine des tumeurs et le déficit lié à la livraison de médicaments chimiothérapeutiques pourrait en partie résulter de cette influence vasomodulatory. Pour tester cette hypothèse, nous nous sommes concentrés sur l'endothéline-1 (ET-1), qui, outre ses effets sur la tumeur autocrine la croissance cellulaire, est un puissant vasoconstricteur. We first document that an ET A receptor antagonist induced relaxation of microdissected tumor arterioles and selectively and quantitatively increased tumor blood flow in experimental tumor models. Nous premier document qu'un antagoniste des récepteurs ET A la relaxation induite par des artérioles tumeur microdisséquées et sélectivement et quantitativement l'augmentation du débit sanguin tumorale dans des modèles expérimentaux de tumeurs. We then combined dye staining of functional vessels, fluorescent microsphere-based mapping, and magnetic resonance imaging to identify heterogeneities in tumor blood flow and to examine the reversibility of such phenomena. Nous avons ensuite combiné de la coloration des vaisseaux fonctionnels, fluorescent à base de microsphères de cartographie et d'imagerie par résonance magnétique pour identifier les hétérogénéités du débit sanguin des tumeurs et d'examiner la réversibilité de ces phénomènes. Data from all these techniques concurred to show that administration of an ET A receptor antagonist could reduce the extent of underperfused tumor areas, proving the key role of vessel tone variations in tumor blood flow heterogeneity. Les données de toutes ces techniques d'accord pour montrer que l'administration d'un antagoniste des récepteurs ET A pourrait réduire l'étendue des zones tumorales underperfused, ce qui prouve le rôle clé du navire variations des flux de ton hétérogénéité sanguins des tumeurs. We also provide evidence that ET A antagonist administration could, despite an increase in tumor interstitial fluid pressure, improve access of cyclophosphamide to the tumor compartment and significantly influence tumor growth. Nous avons également fournir la preuve que l'administration antagoniste ET A pourrait, en dépit d'une augmentation de la tumeur interstitielle pression d'un fluide, d'améliorer l'accès de cyclophosphamide dans le compartiment des tumeurs et une influence significative sur la croissance tumorale. In conclusion, tumor endogenous ET-1 production participates largely in the temporal and spatial variations in tumor blood flow. En conclusion, une tumeur ET-1 endogène de production participe largement à l'espace et les variations temporelles du flux sanguin tumoral. ET A antagonist administration may wipe out such heterogeneities, thus representing an adjuvant strategy that could improve the delivery of conventional chemotherapy to tumors. ET Une administration antagoniste peut effacer ces hétérogénéités, ce qui représente une stratégie adjuvant qui pourraient améliorer la prestation de la chimiothérapie conventionnelle des tumeurs. [Mol Cancer Ther 2006;5(6):1620–7] [Cancer Mol Il 2006; 5 (6) :1620-7]Maturation of tumor vasculature involves the recruitment of pericytes that protect the endothelial tubes from a variety of stresses, including antiangiogenic drugs. Mural cells also provide mature tumor blood vessels with the ability to either relax or contract in response to substances present in the tumor microenvironment. The observed cyclic alterations in tumor blood flow and the associated deficit in chemotherapeutic drug delivery could in part arise from this vasomodulatory influence. To test this hypothesis, we focused on endothelin-1 (ET-1), which, besides its autocrine effects on tumor cell growth, is a powerful vasoconstrictor. We first document that an ETA receptor antagonist induced relaxation of microdissected tumor arterioles and selectively and quantitatively increased tumor blood flow in experimental tumor models. We then combined dye staining of functional vessels, fluorescent microsphere-based mapping, and magnetic resonance imaging to identify heterogeneities in tumor blood flow and to examine the reversibility of such phenomena. Data from all these techniques concurred to show that administration of an ETA receptor antagonist could reduce the extent of underperfused tumor areas, proving the key role of vessel tone variations in tumor blood flow heterogeneity. We also provide evidence that ETA antagonist administration could, despite an increase in tumor interstitial fluid pressure, improve access of cyclophosphamide to the tumor compartment and significantly influence tumor growth. In conclusion, tumor endogenous ET-1 production participates largely in the temporal and spatial variations in tumor blood flow. ETA antagonist administration may wipe out such heterogeneities, thus representing an adjuvant strategy that could improve the delivery of conventional chemotherapy to tumors. [Mol Cancer Ther 2006;5(6):1620–7

The association of N-palmitoylethanolamine with the FAAH inhibitor URB597 impairs melanoma growth through a supra-additive action

<p>Abstract</p> <p>Background</p> <p>The incidence of melanoma is considerably increasing worldwide. Frequent failing of classical treatments led to development of novel therapeutic strategies aiming at managing advanced forms of this skin cancer. Additionally, the implication of the endocannabinoid system in malignancy is actively investigated.</p> <p>Methods</p> <p>We investigated the cytotoxicity of endocannabinoids and their hydrolysis inhibitors on the murine B16 melanoma cell line using a MTT test. Enzyme and receptor expression was measured by RT-PCR and enzymatic degradation of endocannabinoids using radiolabeled substrates. Cell death was assessed by Annexin-V/Propidium iodine staining. Tumors were induced in C57BL/6 mice by s.c. flank injection of B16 melanoma cells. Mice were injected i.p. for six days with vehicle or treatment, and tumor size was measured each day and weighted at the end of the treatment. Haematoxylin-Eosin staining and TUNEL assay were performed to quantify necrosis and apoptosis in the tumor and endocannabinoid levels were quantified by HPLC-MS. Tube formation assay and CD31 immunostaining were used to evaluate the antiangiogenic effects of the treatments.</p> <p>Results</p> <p>The <it>N</it>-arachidonoylethanolamine (anandamide, AEA), 2-arachidonoylglycerol and <it>N</it>- palmitoylethanolamine (PEA) reduced viability of B16 cells. The association of PEA with the fatty acid amide hydrolase (FAAH) inhibitor URB597 considerably reduced cell viability consequently to an inhibition of PEA hydrolysis and an increase of PEA levels. The increase of cell death observed with this combination of molecules was confirmed in vivo where only co-treatment with both PEA and URB597 led to decreased melanoma progression. The antiproliferative action of the treatment was associated with an elevation of PEA levels and larger necrotic regions in the tumor.</p> <p>Conclusions</p> <p>This study suggests the interest of targeting the endocannabinoid system in the management of skin cancer and underlines the advantage of associating endocannabinoids with enzymatic hydrolysis inhibitors. This may contribute to the improvement of long-term palliation or cure of melanoma.</p

Implication du facteur de transcription HNF-6 dans l'hématopoïèse

The identification of transcription factors that participate to the mechanisms of lymphoid development have helped to understand this process. One way to study the role of these factors is to analyze the phenotype of mice in which the gene coding for e particular transcription factor has been inactivated (knockout mice). Hepatocyte nuclear factor-6 (HFN-6); discovered in the laboratory, is the prototype of a new class, called Onecut, of evolutionarily conserved proteins that contain a single cut domain and a divergent homeodomain. HNF-6 is required for proper development of the biliary tract and of the pancreas, which illustrates the role of this factor in development. Preliminary datas suggested that HNF-6 could also control hematopoiesis. In the course of this doctoral work, we first showed that hfn6 is not expressed constitutively in hematopoietic tissues from adult or fetal mice, irrespective of the strain of mice and of their immunisation status. However, we demonstrated in vitro that cytokines like oncostatin M are able to induce hnf6 expression. We discovered that the inactivation of the hnf6 gene in the mouse leads to decreased B lumphopoiesis and to increased granulopoiesis. We focussed on B lymphopoiesis and showed that HNF-6 regulates in the fetal liver, but not in adult bone marrow. Our data suggested that HNF-6 controls an early stage o B cell development. They also showed that this control is indirect and involves an influence of nonhematopoietic cells of fetal liver on B cell precursors. Indeed, parenchymal cells, but not hematopoietic cells, expressed hnf6. Moreover, hematopoietic cells from hnf6-/- fetal liver could reconstitute the lymphoid system when injected into scid mice. Gene expression analysis in the liver of hnf6-/- embryos allowed us to exclude in these animals altered expression on extrinsic known to be implicated in B lymphopoiesis such as IL-7, IGF-I, IGF-II, SCF and OSMR. Modifications of gene expression in the HGF signaling pathway were identified, but our experiments excluded their involvement in the lymphoid phenotype of hnf6-/- mice. However, our observations indicated that this phenotype could result from excessive signaling through the TGFβ pathway. Thus, hnf6 knockout mice are the first example of a liver-specific defect of hematopoietis and provide an original model for studying the interaction between hematopoietic cells and cells of the hepatic microenvironmentLa découverte de facteurs de transcription qui participent aux mécanismes du développement du système lymphoïde a été un progrès majeur dans la compréhension de ce processus. Une façon d'étudier le rôle de ces facteurs est d'analyser le phénotype des souris chez lesquelles le gène codnt un facteur de transcription particulier a été inactivé (souris "knockout"). Le facteur de transcription HNF-6 (Hepatocyte Nuclear Factor-6), découvert au laboratoire, est le prototype d'une nouvelle classe, appelée Onecut, de protéines qui contiennent un domaine cut unique et un domaine homéo particulier et qui ont été très conservées au cours de l'évolution. HNF-6 est requis pour la formation correcte du tractus biliaire et du pancréas, ce qui illustre le rôle de ce facteur dans le développement. Des résultats préliminaires faisaient penser que HNF-6 pourrait également contrôler l'hématopoïèse. Dans le cadre de cette thèse de doctorat, nous avons montré tout d'abord que "hnf6" n'est pas exprimé constitutivement dans les tissus hématopoïétiques murins adultes ou foetaux et ce, quels que soient la souche de souris ou leur état d'immunisation. Néanmoins, nous avons démontré in vitro que certaines cytokines telles que l'oncostatine M sont capables d'induire l'expession de "hnf6". Nous avons découvert que l'inactivation du gène "hnf6" chez la souris diminue la lymphopoïèse B et augmente la granulopoïèse. Nous avons particulièrement étudié la lymphopoïèse B et avons montré que HNF-6 régule celle-ci dans le foie foetal, mais pas dans la moelle adulte. Nos données suggèrent que HNF-6 contrôle un stade précoce du développement des cellules B. Elles montrent également que ce contrôle est indirect et implique une influence des cellules non-hématopoïétiques du foie foetal sur des précurseurs des cellules B. En effet, les cellules parenchymateuses, mais pas les cellules hématopoïétiques, expriment "hnf6". De plus, les cellules hématopoïétiques de foie foetal "hnf6-/-" sont capables de reconstituer le système lymphoïde quand elles sont infectées dans des souris "scid". L'analyse de l'expression de gènes dans le foie des embryons "hnf6-/-" a permis d'exclure chez ceux-ci des anomalies de l'expression de facteurs extrinsèques connus pour leur rôle dans la lymphopoïèse B tels que IL-7, SDF-1, IGF-I, IGF-II, SCF et OSMR. Des modifications de l'expression de gènes de la voie de signalisation par HGF ont été identifiées, mais nos expériences en excluent l'implication dans le phénotype lymphopoïde des souris "hnf6-/-". Cependant, nos observations indiquent que ce phénotype pourrait résulter d'une signalisation excessive par la voie TGFβ. Tous ces résultats font des souris "hnf6-/-" le premier exemple d'un défaut hépatospécifique de l'hématopoïèse et un nouveau modèle d'étude de l'interaction entre les cellules hématopoïétiques et les cellules du microenvironnement hépatique.Thèse de doctorat en sciences pharmaceutiques -- UCL, 200

Targeting tumor stroma and exploiting mature tumor vasculature to improve anti-cancer drug delivery.

The identification of a critical role of tumour stroma in the regulation of tumour interstitial fluid pressure and the simultaneous discovery of the impact of anti-angiogenic drugs on tumour hemodynamics have provided new potential for improving tumour delivery of anti-cancer drugs. Here, we review the most recent studies investigating how tumour-associated fibroblasts and macrophages as well as the extracellular matrix itself may be targeted to facilitate delivery of both low-molecular weight drugs and macromolecules. In addition, we summarize the current understanding of the use of vasoactive compounds, radiotherapy and vascular-disrupting agents as potential adjuvants to maximize tumour delivery of anti-cancer drugs. The impact of these strategies on the diffusive and convective modes of drug transport is discussed in the light of Fick's and Starling's laws. Finally, we discuss how transcytosis through caveolae may also be exploited to optimize the selective delivery of conventional chemotherapy to the subendothelial tumour cell compartment

IMPORTANCE DU CADRE THERAPEUTIQUE DANS LES TRAITEMENTS DE KINESITHERAPIEET DE RELAXATION

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

An Appraisal of Proliferation and Apoptotic Markers in Papillary Thyroid Carcinoma: An Automated Analysis.

INTRODUCTION: Proliferation and apoptosis are opposing processes by which the cell numbers are kept in a delicate balance, essential for tissue homeostasis, whereas uncontrolled growth of cells is a hallmark of cancer. Papillary thyroid cancer (PTC) is the commonest type of thyroid cancer, with some PTC following an indolent course, whereas the other ones are more aggressive. AIM: To evaluate respective contribution of proliferation and apoptosis in the tumorigenesis of PTC by automated analysis. MATERIALS AND METHODS: We investigated the immunolabeling of phosphorylated histone H3 (pHH3), cyclin D1, active caspase-3, and bcl-2 in thirteen cases each of metastatic PTC, follicular variant of PTC (FVPTC), papillary microcarcinoma (PMC) and well differentiated tumor of uncertain malignant potential (WDT-UMP). FVPTC cases comprised seven encapsulated and six unencapsulated cases. RESULTS: Proliferation, as assessed by pHH3 and cyclin D1 immunolabeling, was increased in all PTC variants, including the putative precursor lesion WDT-UMP, compared to normal thyroid tissue. pHH3 was immunolabeled in more cells of metastatic PTC than of PMC and of encapsulated FVPTC. Surprisingly, metastatic PTC and unencapsulated FVPTC also demonstrated more cleaved caspase-3 immunolabeled cells than the other types. In contrast, increased expression of bcl-2 protein was seen in normal thyroid areas, encapsulated FVPTC and PMC as compared to metastatic PTC. Metastatic PTC shows higher proliferation than other types of PTC but unexpectedly also higher apoptotic levels. Similar results were also seen with unencapsulated FVPTC, thus suggesting that unencapsulated FVPTC has a potential for adverse outcome. Bcl-2 was immunolabeled in a low percentage of cells in WDT-UMP. CONCLUSIONS: The expression of the proliferative protein pHH3 together with the apoptotic marker cleaved caspase-3 may indicate an aggressive behaviour of PTC and loss of apoptosis inhibition by bcl-2 protein can further amplify the role of these proteins in tumor progression. Both cyclin D1 and bcl-2 could prove to be interesting markers of PTC precursor lesions. Automated/digital image quantification approach helps in refining the diagnostic accuracy