Isoform 111 of vascular endothelial growth factor (VEGF111) improves angiogenesis of ovarian tissue xenotransplantation

in Transplantation (2013), 95(3), 426-433

Background: Cryopreservation of cortex ovarian tissue before anti-cancer therapy is a promising technique for fertility preservation mainly in children and young women. Ischemia in the early stage after ... [more ▼]

Background: Cryopreservation of cortex ovarian tissue before anti-cancer therapy is a promising technique for fertility preservation mainly in children and young women. Ischemia in the early stage after ovarian graft causes massive follicle loss by apoptosis. VEGF111 is a recently described VEGF isoform that does not bind to the extracellular matrix, diffuse extensively and is resistant to proteolysis. These properties confer a significantly higher angiogenic potential to VEGF111 in comparison to the other VEGF isoforms. Methods: We evaluated the morphology of cryopreserved sheep ovarian cortex, grafted in the presence or absence of VEGF111. Ovarian cortex biopsies were embedded in type I collagen with or without VEGF111 addition before transplantation to SCID mice ovaries. Transplants were retrieved 3 days or 3 weeks later. Follicular density, vasculature network, haemoglobin content and cell proliferation were analysed. Results: Addition of VEGF111 increased density of functional capillaries (p=0.01) 3 days after grafting. By double immunostaining of Ki-67 and von Willebrand Factor (vWF) we demonstrated that proliferating endothelial cells were found in 83% of the VEGF111 group when compared to 33% in the control group (p=0.001). This angio-stimulation was associated with a significant enhancement of haemoglobin content (p=0.03). Three weeks after transplantation, the number of primary follicles was significantly higher in VEGF111 grafts (p=0.02). Conclusion: VEGF111 accelerates blood vessels recruitment, functional angiogenesis and improves the viability of ovarian cortex by limiting ischemia and ovarian cortex damage. [less ▲]

Séminaire des chercheurs Télévie 2013

Poster (2012, December 10)

Séminaire des chercheurs Télévie 2013

Matrix metalloproteinase-2 governs lymphatic vessel formation as an interstitial collagenase.

in Blood (2012), 119(21), 5048-56

Lymphatic dysfunctions are associated with several human diseases, including lymphedema and metastatic spread of cancer. Although it is well recognized that lymphatic capillaries attach directly to ... [more ▼]

Lymphatic dysfunctions are associated with several human diseases, including lymphedema and metastatic spread of cancer. Although it is well recognized that lymphatic capillaries attach directly to interstitial matrix mainly composed of fibrillar type I collagen, the interactions occurring between lymphatics and their surrounding matrix have been overlooked. In this study, we demonstrate how matrix metalloproteinase (MMP)–2 drives lymphatic morphogenesis through Mmp2-gene ablation in mice, mmp2 knockdown in zebrafish and in 3D-culture systems, and through MMP2 inhibition. In all models used in vivo (3 murine models and thoracic duct development in zebrafish) and in vitro (lymphatic ring and spheroid assays), MMP2 blockage or down-regulation leads to reduced lymphangiogenesis or altered vessel branching. Our data show that lymphatic endothelial cell (LEC) migration through collagen fibers is affected by physical matrix constraints (matrix composition, density and cross-linking). Transmission electron microscopy (TEM) and confocal reflection microscopy using DQ-collagen highlight the contribution of MMP2 to mesenchymal-like migration of LEC associated with collagen fiber remodeling. Our findings provide new mechanistic insight into how LEC negotiate an interstitial type I collagen barrier and reveal an unexpected MMP2-driven collagenolytic pathway for lymphatic vessel formation and morphogenesis. [less ▲]

Does vascular endothelial growth factor improve ovarian tissue recovery after cryopreservation?

in Giornale italiano di obstetricia e gynecologia (2012)

Bone Marrow-derived Myofibroblasts Are the Providers of Pro-invasive Matrix Metalloproteinase 13 in Primary Tumor.

in Neoplasia : An International Journal for Oncology Research (2012), 14(10), 943-51

Carcinoma-associated fibroblasts are key contributors of the tumor microenvironment that regulates carcinoma progression. They consist of a heterogeneous cell population with diverse origins, phenotypes ... [more ▼]

Carcinoma-associated fibroblasts are key contributors of the tumor microenvironment that regulates carcinoma progression. They consist of a heterogeneous cell population with diverse origins, phenotypes, and functions. In the present report, we have explored the contribution of bone marrow (BM)-derived cells to generate different fibroblast subsets that putatively produce the matrix metalloproteinase 13 (MMP13) and affect cancer cell invasion. A murine model of skin carcinoma was applied to mice, irradiated, and engrafted with BM isolated from green fluorescent protein (GFP) transgenic mice. We provide evidence that one third of BM-derived GFP(+) cells infiltrating the tumor expressed the chondroitin sulfate proteoglycan NG2 (pericytic marker) or alpha-smooth muscle actin (alpha-SMA, myofibroblast marker), whereas almost 90% of Thy1(+) fibroblasts were originating from resident GFP-negative cells. MMP13producing cells were exclusively alpha-SMA(+) cells and derived from GFP(+) BM cells. To investigate their impact on tumor invasion, we isolated mesenchymal stem cells (MSCs) from the BM of wild-type and MMP13-deficient mice. Wild-type MSC promoted cancer cell invasion in a spheroid assay, whereas MSCs obtained from MMP13-deficient mice failed to. Our data support the concept of fibroblast subset specialization with BM-derived alpha-SMA(+) cells being the main source of MMP13, a stromal mediator of cancer cell invasion. [less ▲]

The proteolytic activity of MT4-MMP is required for its proangiogenic and pro-metastatic promoting effects

in International Journal of Cancer = Journal International du Cancer (2012), 131(7), 1537-1548

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a ... [more ▼]

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a proteolytic action is not known yet. Through site directed mutagenesis MT4-MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4-MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in RAG -/- mice. All these effects were abrogated upon MT4-MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor-derived MT4-MMP, but not host-derived MT4-MMP contributes to angiogenesis. A genetic approach using MT4-MMP-deficient mice revealed that the status of MT4-MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4-MMP requires a permissive microenvironment. Indeed, tumor-derived MT4-MMP failed to circumvent the lack of an host angio-promoting factor such as lasminogen activator inhibitor (PAI-1). Overall, our study demonstrates the key contribution of MT4-MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4-MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination [less ▲]

Stromal Estrogen Receptor-α Promotes Tumor Growth by Normalizing an Increased Angiogenesis.

in Cancer Research (2012), 72(12), 3010-3019

Estrogens directly promote the growth of breast cancers that express the Estrogen Receptor 􏰀 (ERalpha). However, the contribution of stromal expression of ERalpha in the tumor microenvironment to the pro ... [more ▼]

Estrogens directly promote the growth of breast cancers that express the Estrogen Receptor 􏰀 (ERalpha). However, the contribution of stromal expression of ERalpha in the tumor microenvironment to the pro-tumoral effects of estrogen has never been explored. In this study, we evaluated the molecular and cellular mechanisms by which 17beta-estradiol (E2) impacts the microenvironment and modulates tumor development of ERalpha-negative tumors. Using different mouse models of ER-negative cancer cells grafted subcutaneously into syngeneic ovariectomized immunocompetent mice, we found that E2 potentiates tumor growth, increases intratumoral vessel density and modifies tumor vasculature into a more regularly organized structure, thereby improving vessel stabilization to prevent tumor hypoxia and necrosis. These E2-induced effects were completely abrogated in ERalpha-deficient mice, demonstrating a critical role of host ERα. Notably, E2 did not accelerate tumor growth when ERalpha was deficient in Tie2- positive cells, but still expressed by bone marrow derived cells. These results were extended by clinical evidence of ERalpha-positive stromal cell labeling in the microenvironment of human breast cancers. Together, our findings therefore suggest that E2 promotes the growth of ERalpha-negative cancer cells through the activation of stromal ERα (not hematopoiteic but Tie2-dependent expression of ERalpha), which normalizes tumor angiogenesis and allows an adaptation of blood supply to tumor demand preventing hypoxia and necrosis. These findings significantly deepen mechanistic insights into the impact of E2 on tumor development with potential consequences for cancer treatment. [less ▲]

The Antiangiogenic 16K Prolactin Impairs Functional Tumor Neovascularization by Inhibiting Vessel Maturation

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 ▲]

Novel HDAC/DNMT Twin inhibitors interfere with angiogenesis

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 ▲]

Effect of the activating agent on physico-chemical and electrical properties of activated carbon cloths developed from a novel cellulosic precursor

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2011), 378(1-3), 87-93

Different chemical reagents (phosphoric acid, boric acid, ammonium citrate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate and trisodium phosphate) were employed ... [more ▼]

Different chemical reagents (phosphoric acid, boric acid, ammonium citrate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate and trisodium phosphate) were employed to develop activated carbon cloths (ACC) by chemical activation of a lyocell precursor, in an attempt to explore their effect on main physico-chemical characteristics and electrical behaviour of the resulting ACC. The activating agent markedly influenced yield, elemental composition, and textural properties of the ACC. The ACC obtained with phosphoric and boric acids were essentially microporous, whereas those developed with the other reagents presented mesoporosity development. Phosphoric acid-derived samples showed the highest specific surface area (976 m2/g). The results also highlight the relevance of correcting the external surface adsorption in order to obtain reliable estimates of micropore volume. All the ACC were electrically conductive, their resistivity being also strongly dependent on the nature of the activating agent. The electrical resistivity of the ACC obtained with all the phosphorous compounds was successfully correlated with their C/H ratio and micropore volume [less ▲]