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See detailThe Antiangiogenic 16K Prolactin Impairs Functional Tumor Neovascularization by Inhibiting Vessel Maturation
Nguyen, Ngoc-Quynh-Nhu ULg; Castermans, Karolien; Berndt, Sarah et al

in PLoS ONE (2011), 6(11), 27318-27318

Background: Angiogenesis, the formation of new blood vessels from existing vasculature, plays an essential role in tumor growth, invasion, and metastasis. 16K hPRL, the antiangiogenic 16-kDa N-terminal ... [more ▼]

Background: Angiogenesis, the formation of new blood vessels from existing vasculature, plays an essential role in tumor growth, invasion, and metastasis. 16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Methodology/Principal Findings: Here we investigated the effect of 16K hPRL on tumor vessel maturation and on the related signaling pathways. We show that 16K hPRL treatment leads, in a murine B16-F10 tumor model, to a dysfunctional tumor vasculature with reduced pericyte coverage, and disruption of the PDGF-B/PDGFR-B, Ang/Tie2, and Delta/Notch pathways. In an aortic ring assay, 16K hPRL impairs endothelial cell and pericyte outgrowth from the vascular ring. In addition, 16K hPRL prevents pericyte migration to endothelial cells. This event was independent of a direct inhibitory effect of 16K hPRL on pericyte viability, proliferation, or migration. In endothelial cell-pericyte cocultures, we found 16K hPRL to disturb Notch signaling. Conclusions/Significance: Taken together, our data show that 16K hPRL impairs functional tumor neovascularization by inhibiting vessel maturation and for the first time that an endogenous antiangiogenic agent disturbs Notch signaling. These findings provide new insights into the mechanisms of 16K hPRL action and highlight its potential for use in anticancer therapy. [less ▲]

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See detailInhibition of Experimental Corneal Neovascularization by Sunitinib Administration
Detry, Benoît ULg; BLACHER, Silvia ULg; Erpicum, Charlotte ULg et al

Poster (2011, October)

Cornea engraftment is the most common organ transplantation practiced around the world. The cornea is totally devoid of blood or lymphatic vessels, except in a peripheral zone called the limbus. This ... [more ▼]

Cornea engraftment is the most common organ transplantation practiced around the world. The cornea is totally devoid of blood or lymphatic vessels, except in a peripheral zone called the limbus. This property, named “corneal angiogenic privilege”, is conserved among all mammals to maintain cornea transparency and optimal visual acuity. In pathological conditions such as trauma, infections or hypoxia, blood and lymphatic vessels can grow into the avascular cornea, reducing visual acuity. In case of keratoplasty, it also considerably increases the risk of cornea graft rejection and is so considered as a high-risk keratoplasty. Treatments improving cornea survival after transplantation need to be developed, notably aiming at blocking corneal neovascularization. Here, we evaluated the efficacy of Sunitinib, a broad-spectrum tyrosine kinase receptor inhibitor, to reduce experimental corneal neovascularization. Cornea vascularization was induced by thermal cauterization applied in the center of C57Bl6 mice cornea, daily feeded with 40mg/kg Sunitinib or vehicule. Corneas were immunolabeled as whole mounts for CD31 and Lyve-1 to evidence blood and lymphatic vessels, 7, 11 and 17 days after cauterization. Whole mount pictures were analyzed by computer-assisted quantification, and relative vascular area, end-point density, node density, length density and maximal length of the vessels were determined to finely characterize blood and lymphatic vascular networks. We observed an inhibition of angiogenesis after 17 days in Sunitinib treated mice, where blood vessel relative surface, end-point density, branching density and length density were 1.8-fold decreased. Maximum length of blood vessels was also significantly reduced in the Sunitinib treated group at days 11 and 17. Lymphangiogenesis was strongly inhibited from day 6 to day 17 after cauterization where all parameters, except maximum length of lymphatic vessels, were significantly decreased. In case of transient Sunitinib administration (feeding during the 7 first days), we did not observe any reduction in the extent of blood or lymphatic networks developing 21 days after lesion induction. In vitro experimentations using the aortic and lymphatic ring assays showed a strong angiogenesis inhibition induced by Sunitinib while lymphangiogenesis was not inhibited. Our results show that the use of Sunitinib can strongly affect corneal neovascularisation and could enter in early treatment of such eye lesions to avoid vision loss and risk of cornea graft rejection. However, a punctual use of such tyrosine kinase inhibitor is not sufficient to stem neovascular reaction. In vitro experimentations show strong angiogenesis inhibition but normal lymphangiogenesis, suggesting indirect inhibitory effect of Sunitinib on corneal lymphangiogenesis. [less ▲]

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See detailDigging deeper into lymphatic vessel formation in vitro and in vivo
Detry, Benoît ULg; Bruyère, F.; Erpicum, Charlotte ULg et al

in BMC Cell Biology (2011), 12

Background Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays ... [more ▼]

Background Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays distinctive features than blood vasculature, and mechanisms underlying the formation of new lymphatic vessels during physiological and pathological processes are still poorly documented. Most studies on lymphatic vessel formation are focused on organism development rather than lymphangiogenic events occurring in adults. We have here studied lymphatic vessel formation in two in vivo models of pathological lymphangiogenesis (corneal assay and lymphangioma). These data have been confronted to those generated in the recently set up in vitro model of lymphatic ring assay. Ultrastructural analyses through Transmission Electron Microscopy (TEM) were performed to investigate tube morphogenesis, an important differentiating process observed during endothelial cell organization into capillary structures. [less ▲]

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See detailMT-MMPs as regulators of vessel stability associated with angiogenesis
Sounni, Nor Eddine ULg; Paye, Alexandra ULg; Host, Lorin et al

in Frontiers in Pharmacology of Anti-Cancer Drugs (2011), 2:111

The development of vascular system depends on the coordinated activity of a number of distinct families of molecules including growth factors and their receptors, cell adhesion molecules, extracellular ... [more ▼]

The development of vascular system depends on the coordinated activity of a number of distinct families of molecules including growth factors and their receptors, cell adhesion molecules, extracellular matrix (ECM) molecules, and proteolytic enzymes. Matrix metalloproteases (MMPs) are a family of ECM degrading enzymes required for both physiological and pathological angiogenesis. Increasing evidence, point to a direct role of membrane type-MMPs (MT-MMPs) in vascular system stabilization, maturation, and leakage. Our understanding of the nature of MT-MMP interaction with extracellular and cell surface molecules and their multiple roles in vessel walls and perivascular stroma may provide new insights into mechanisms underlying vascular cell-ECM interactions and cell fate decisions in pathological conditions. Regulation of vascular leakage by MT-MMP interactions with the ECM could also lead to novel targeting opportunities for drug delivery in tumor. This review will shed lights on the emerging roles of MT1-MMP and MT4-MMP in vascular system alterations associated with cancer progression. [less ▲]

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See detailInvolvement of z-MMP-2 in Zebrafish lymphangiogenesis
Paupert, Jenny ULg; Pendeville, Hélène; Detry, Benoît ULg et al

Poster (2011, May)

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See detailThe antiangiogenic 16K prolactin disturbs functional tumor neovascularization by affecting vessel maturation
Nguyen, Ngoc-Quynh-Nhu ULg; Castermans, Karolien; Berndt, Sarah et al

Poster (2011, May)

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K ... [more ▼]

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K hPRL on tumor vessel maturation and on the related signaling pathways. We show that 16K hPRL treatment leads, in a murine B16-F10 tumor model, to a dysfunctional tumor vasculature with reduced pericyte coverage, and disruption of the PDGF-B/PDGFR-B, Ang/Tie2, and Delta/Notch pathways. In an aortic ring assay, 16K hPRL impairs endothelial cell and pericyte outgrowth from the vascular ring. In addition, 16K hPRL prevents pericyte migration to endothelial cells. This event was independent of a direct inhibitory effect of 16K hPRL on pericyte viability, proliferation, or migration. In endothelial cell-pericyte cocultures, we found 16K hPRL to disturb Notch signaling, this being the first time such an effect is observed with an endogenous antiangiogenic agent. These findings provide new insights into the mechanisms of 16K hPRL action and highlight its potential for use in anticancer therapy. [less ▲]

Detailed reference viewed: 35 (5 ULg)
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See detailMir-146a : A new angiostatic miRNA with tumor-suppressive properties
Halkein, Julie ULg; Castermans, Karolien; Malvaux, Ludovic et al

Poster (2011, March)

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See detailMiR-146a an angiostatic miRNA elevated in peripartum cardiomyopathy
Halkein, Julie ULg; Castermans, Karolien; Malvaux, Ludovic et al

Poster (2011, March)

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See detailMiR-146a: an angiostatic miRNA with tumor-suppressive properties
Halkein, Julie ULg; Bovy, Nicolas ULg; Castermans, Karolien et al

Poster (2011, February)

Detailed reference viewed: 17 (7 ULg)
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See detailMiR-146a an angiostatic miRNA elevated in peripartum cardiomyopathy
Halkein, Julie ULg; Castermans, Karolien; Malvaux, Ludovic et al

Poster (2011, February)

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See detailmicroRNA-21 Exhibits Anti-Angiogenic Function by Targeting RhoB Expression in Endothelial Cells
Sabatel, Céline; Malvaux, Ludovic; Bovy, Nicolas ULg et al

Poster (2011, February)

Detailed reference viewed: 10 (3 ULg)
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See detailNovel HDAC/DNMT Twin inhibitors interfere with angiogenesis
Shiva Shankar, Thammadihalli Veerasangaiah ULg; Sulka, Béatrice ULg; Blacher, Silvia ULg et al

Poster (2011, January 31)

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA ... [more ▼]

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA methyltransferases (DNMT) inhibitors are potent anti-angiogenic compounds. Though combination of HDAC and DNMT inhibitors are now being examined in clinical trials of hematological malignancies, little work has been done to understand the effect of this combination on physiological and tumoral angiogenesis. We have designed and tested a family of twin drugs with intrinsic HDAC and DNMT inhibitory activities in relevant models of angiogenesis in vitro (Human Umbilical Vein Endothelial Cells – HUVEC and aortic ring) and in vivo (chick chorioallantoic membrane and Zebrafish). We have identified a lead compound having quantifiable anti-angiogenic effect without cytotoxicity affecting global histone acetylation and DNA methylation levels. In order to elucidate its anti-angiogenic mechanism, we characterized gene expression pattern simultaneously with the methylation profile of HUVEC cells treated with the lead compound and reference epigenetic modulators. This approach based on parallel microarray analyses permitted us to underscore a list of genes exclusively affected by the lead compound but not by other HDAC or DNMT inhibitors. These genes were then analyzed using the Ingenuity Pathway software revealing potential involvement of a subset of genes in angiogenesis. Our present aim is to validate the expression levels of a series of genes with respect to epigenetic mechanisms (histone modifications and DNA methylation). Finally, the biological relevance of the target genes will be explored by RNA silencing. Hence, we are using these novel epigenetic modulators as a tool to understand the regulatory mechanism of angiogenesis and to develop effective approaches to treat cancer. [less ▲]

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See detaildoes neoadjuvant radiotherapy promote tumor dissemination ,
Leroi, Natacha ULg; boujouf, Sarah; COUCKE, Philippe ULg et al

Poster (2011, January)

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See detailMiR-146a an angiostatic miRNA elevated in peripartum cardiomyopathy
Halkein, Julie ULg; Castermans, Karolien; Malvaux, Ludovic et al

Poster (2011, January)

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See detailNuclear delivery of a therapeutic peptide by long circulating pH-sensitive liposomes: Benefits over classical vesicles.
Ducat, Emilie ULg; Deprez, Julie ULg; Gillet, Aline ULg et al

in International Journal of Pharmaceutics (2011)

The purpose of this study is to propose a suitable vector combining increased circulation lifetime and intracellular delivery capacities for a therapeutic peptide. Long circulating classical liposomes ... [more ▼]

The purpose of this study is to propose a suitable vector combining increased circulation lifetime and intracellular delivery capacities for a therapeutic peptide. Long circulating classical liposomes [SPC:CHOL:PEG-750-DSPE (47:47:6 molar% ratio)] or pH-sensitive stealth liposomes [DOPE:CHEMS:CHOL:PEG(750)-DSPE (43:21:30:6 molar% ratio)] were used to deliver a therapeutic peptide to its nuclear site of action. The benefit of using stealth pH-sensitive liposomes was investigated and formulations were compared to classical liposomes in terms of size, shape, charge, encapsulation efficiency, stability and, most importantly, in terms of cellular uptake. Confocal microscopy and flow cytometry were used to evaluate the intracellular fate of liposomes themselves and of their hydrophilic encapsulated material. Cellular uptake of peptide-loaded liposomes was also investigated in three cell lines: Hs578t human epithelial cells from breast carcinoma, MDA-MB-231 human breast carcinoma cells and WI-26 human diploid lung fibroblast cells. The difference between formulations in terms of peptide delivery from the endosome to the cytoplasm and even to the nucleus was investigated as a function of time. Characterization studies showed that both formulations possess acceptable size, shape and encapsulation efficiency but cellular uptake studies showed the important benefit of the pH-sensitive formulation over the classical one, in spite of liposome PEGylation. Indeed, stealth pH-sensitive liposomes were able to deliver hydrophilic materials strongly to the cytoplasm. Most importantly, when encapsulated in pH-sensitive stealth liposomes, the peptide was able to reach the nucleus of tumorigenic and non tumorigenic breast cancer cells. [less ▲]

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See detailNovel HDAC/DNMT Twin Inhibitors Interfere with Angiogenesis
Shiva Shankar, Thammadihalli Veerasangaiah ULg; Sulka, Béatrice ULg; Blacher, Silvia ULg et al

Poster (2011)

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA ... [more ▼]

DNA methylation and histone deacetylation are two key epigenetic modifications that play central role in regulation of gene expression. Several studies have shown that histone deacetylases (HDAC) and DNA methyltransferases (DNMT) inhibitors are potent anti-angiogenic compounds. Though combination of HDAC and DNMT inhibitors are now being examined in clinical trials of hematological malignancies, little work has been done to understand the effect of this combination on physiological and tumoral angiogenesis. We have designed and tested a family of twin drugs with intrinsic HDAC and DNMT inhibitory activities in relevant models of angiogenesis in vitro (Human Umbilical Vein Endothelial Cells – HUVEC and aortic ring) and in vivo (chick chorioallantoic membrane and Zebrafish). We have identified a lead compound having quantifiable anti-angiogenic effect without cytotoxicity affecting global histone acetylation and DNA methylation levels. In order to elucidate its anti-angiogenic mechanism, we characterized gene expression pattern simultaneously with the methylation profile of HUVEC cells treated with the lead compound and reference epigenetic modulators. This approach based on parallel microarray analyses permitted us to underscore a list of genes exclusively affected by the lead compound but not by other HDAC or DNMT inhibitors. These genes were then analyzed using the Ingenuity Pathway software revealing potential involvement of a subset of genes in angiogenesis. Our present aim is to validate the expression levels of a series of genes with respect to epigenetic mechanisms (histone modifications and DNA methylation). Finally, the biological relevance of the target genes will be explored by RNA silencing. Hence, we are using these novel epigenetic modulators as a tool to understand the regulatory mechanism of angiogenesis and to develop effective approaches to treat cancer. [less ▲]

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See detailEnhanced Activity of Meprin-a, a Pro-Migratory and Pro-Angiogenic Protease, in Colorectal Cancer
Lottaz, Daniel; Maurer, Christoph A; Noël, Agnès ULg et al

in PLoS ONE (2011), 6(11), 26450

Meprin-α is a metalloprotease overexpressed in cancer cells, leading to the accumulation of this protease in a subset of colorectal tumors. The impact of increased meprin-α levels on tumor progression is ... [more ▼]

Meprin-α is a metalloprotease overexpressed in cancer cells, leading to the accumulation of this protease in a subset of colorectal tumors. The impact of increased meprin-α levels on tumor progression is not known. We investigated the effect of this protease on cell migration and angiogenesis in vitro and studied the expression of meprin-α mRNA, protein and proteolytic activity in primary tumors at progressive stages and in liver metastases of patients with colorectal cancer, as well as inhibitory activity towards meprin-α in sera of cancer patient as compared to healthy controls. We found that the hepatocyte growth factor (HGF)- induced migratory response of meprin-transfected epithelial cells was increased compared to wild-type cells in the presence of plasminogen, and that the angiogenic response in organ-cultured rat aortic explants was enhanced in the presence of exogenous human meprin-α. In patients, meprin-α mRNA was expressed in colonic adenomas, primary tumors UICC (International Union Against Cancer) stage I, II, III and IV, as well as in liver metastases. In contrast, the corresponding protein accumulated only in primary tumors and liver metastases, but not in adenomas. However, liver metastases lacked meprin-α activity despite increased expression of the corresponding protein, which correlated with inefficient zymogen activation. Sera from cancer patients exhibited reduced meprin-α inhibition compared to healthy controls. In conclusion, meprin-α activity is regulated differently in primary tumors and metastases, leading to high proteolytic activity in primary tumors and low activity in liver metastases. By virtue of its pro-migratory and pro-angiogenic activity, meprin-α may promote tumor progression in colorectal cancer. [less ▲]

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See detailLymphangiogenesis and extracellular matrix remodeling
Erpicum, Charlotte ULg; Detry, Benoît ULg; Paupert, Jenny ULg et al

Poster (2011)

Lymphangiogenesis, the formation of new lymphatic vessels from preexisting ones, is an important biological process associated with diverse pathologies, such as metastatic dissemination and graft ... [more ▼]

Lymphangiogenesis, the formation of new lymphatic vessels from preexisting ones, is an important biological process associated with diverse pathologies, such as metastatic dissemination and graft rejection. Our laboratory has previously identified MMP2 as a key regulator of lymphangiogenesis in vitro and in vivo. However, the exact function of MMP2 in this process is yet unknown. The present work aims at elucidating the mechanisms of MMP2 action during lymphangiogenesis. MMP2 could either act as a growth factor activator or as a regulator of matrix remodeling. To address this question, we studied the effect of MMP2 on lymphangiogenesis in an novel in vitro model of sprouting cells from small aggregates (spheroids) seeded in a collagen gel. In this model, quantification of the lymphangiogenic response is performed through computerized methods allowing the measurement of the distance of migration, but also the evaluation of how the cell are migrating. We evaluated the impact of MMP2 blockage through the use of physiological (TIMP2) or chemical inhibitors or by downregulating its expression with specific siRNA. The importance of extracellular matrix composition is evaluated by embedding these spheroids into different matrices (matrigel versus collagen; pepsinized collagen versus native collagen; different collagen concentrations). Our results reveal a modification of cell migration through collagen gel after MMP2 inhibition. The utilization of DQ collagen and microscopy refractance confirmed the importance of MMP2 collagenoyitic activity for lymphangiogenesis. [less ▲]

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See detailInvasion and metastatic dissemination in breast cancer: mechanisms
Noël, Agnès ULg; Gilles, Christine ULg; Foidart, Jean-Michel ULg

in Revue Médicale de Liège (2011), 66(5-6), 274-278

Metastases formation is a complex process involving genetic and epigenetic modifications leading to several molecular pathway dysfunctions and alterations in the production and fonction of a panel of ... [more ▼]

Metastases formation is a complex process involving genetic and epigenetic modifications leading to several molecular pathway dysfunctions and alterations in the production and fonction of a panel of molecular mediators. Recent studies have shed light on the importance of multiple interactions occuring between tumor cells and host cells involved in the elaboration of a microenvironment permissive for tumor cell survival and growth. These tumor-host interactions are decisive, not only in the primary tumor, but also in secondary sites colonized by tumor cells. Cancer appears more and more as a sytemic disease in which tumor cell is one of the pawn in the game. System of defense are rapidly overwhelmed and tumor cells hijack host cells to promote their dissemination that likely occurs at earlier stages than initially anticipated. In the present review, we describe the novel concepts of metastases formation based on recent transcriptomic analyses and new insights acquired on the tumor microenvironment in the primary tumor and in secondary foci. [less ▲]

Detailed reference viewed: 111 (7 ULg)