Sandro De Falco

National Research Council, Roma, Latium, Italy

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Publications (40)238.1 Total impact

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    ABSTRACT: Hypoxia plays a crucial role in the angiogenic switch, modulating a large set of genes mainly through the activation of hypoxia-inducible factor (HIF) transcriptional complex. Endothelial cells play a central role in new vessels formation and express placental growth factor (PlGF), a member of vascular endothelial growth factor (VEGF) family, mainly involved in pathological angiogenesis. Despite several observations suggest a hypoxia-mediated positive modulation of PlGF, the molecular mechanism governing this regulation has not been fully elucidated. We decided to investigate if epigenetic modifications are involved in hypoxia-induced PlGF expression. We report that PlGF expression was induced in cultured human and mouse endothelial cells exposed to hypoxia (1% O 2), although DNA methylation at the Plgf CpG-island remains unchanged. Remarkably, robust hyperacetylation of histones H3 and H4 was observed in the second intron of Plgf, where hypoxia responsive elements (HREs), never described before, are located. HIF-1α, but not HIF-2α, binds to identified HREs. Noteworthy, only HIF-1αsilencing fully inhibited PlGF upregulation. These results formally demonstrate a direct involvement of HIF-1α in the upregulation of PlGF expression in hypoxia through chromatin remodeling of HREs sites. Therefore, PlGF may be considered one of the putative targets of anti-HIF therapeutic applications.
    Epigenetics: official journal of the DNA Methylation Society 02/2014; 9(4). · 4.58 Impact Factor
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    Sandro De Falco
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    ABSTRACT: Angiogenesis is a complex biological phenomenon that forms new blood vessels from the pre-existing vasculature. Aberrant angiogenesis has been implicated in a variety of diseases such as cancer, atherosclerosis, arthritis, obesity, pulmonary hypertension, diabetic retinopathy, and age-related macular degeneration. These conditions collectively affect nearly 10% of the global population. Much effort has focused on identifying new therapeutic agents that inhibit pathological angiogenesis since 1971, when Judah Folkman published the hypothesis that tumor growth is angiogenesis-dependent and that its inhibition may be therapeutic. In 2004, the U.S. Food and Drug Administration approved the first antiangiogenic drug for the treatment of metastatic colon cancer, bevacizumab (Avastin, Genentech). This drug is a humanized monoclonal antibody that neutralizes the vascular endothelial growth factor. It is used in combination with chemotherapy, and its use began the era of antiangiogenesis therapy. Several new therapeutic agents have been added to the list of approved drugs, and clinical trials of new therapeutic options and antiangiogenic agents are ongoing. This review describes the progress made in the first decade of antiangiogenesis therapy, and addresses both validated and possible targets for future drug development.
    The Korean Journal of Internal Medicine 01/2014; 29(1):1-11.
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    ABSTRACT: The semi-synthetic ent-kaurane 15-ketoatractyligenin methyl ester (SC2017) has been previously reported to possess high antiproliferative activity against several solid tumor-derived cell lines. Our study was aimed at investigating SC2017 tumor growth-inhibiting activity and the underlying mechanisms in Jurkat cells (T-cell leukemia) and xenograft tumor models. Cell viability was evaluated by MTT assay. Cell cycle progression, reactive oxygen species (ROS) elevation and apoptotic hallmarks were monitored by flow cytometry. Inhibition of Thioredoxin reductase (TrxR) by biochemical assays. Levels and/or activation status of signalling proteins were assessed by western blotting. Xenograft tumors were generated with HCT 116 colon carcinoma cells. SC2017 displayed cell growth-inhibiting activity against Jurkat cells (IC50<2μM), but low cell-killing potential in human peripheral blood mononuclear cells (PBMC). The primary response of Jurkat cells to SC2017 was an arrest in G2 phase followed by caspase-dependent apoptosis. Inhibition of PI3K/Akt pathway and TrxR activity by SC2017 was demonstrated by biochemical and pharmacological approaches. At least, SC2017 was found to inhibit xenograft tumor growth. Our results demonstrate that SC2017 inhibits tumor cell growth in in vitro and in vivo models, but displays moderate toxicity against PBMC. We also demonstrate that SC2017 promotes caspase-dependent apoptosis in Jurkat cells by affecting Akt activation status and TrxR functionality. Our observations suggest the semi-synthetic ent-kaurane SC2017 as a promising chemotherapeutic compound. SC2017 has, indeed, shown to possess tumor growth inhibiting activity and be able to counteract PI3K/Akt and Trx system survival signalling.
    Biochimica et Biophysica Acta 12/2013; · 4.66 Impact Factor
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    ABSTRACT: Neovascular age-related macular degeneration is a leading cause of irreversible vision loss in the Western world. Cytokine-targeted therapies (such as anti-vascular endothelial growth factor) are effective in treating pathologic ocular angiogenesis, but have not led to a durable effect and often require indefinite treatment. Here, we show that Nutlin-3, a small molecule antagonist of the E3 ubiquitin protein ligase MDM2, inhibited angiogenesis in several model systems. We found that a functional p53 pathway was essential for Nutlin-3-mediated retinal antiangiogenesis and disruption of the p53 transcriptional network abolished the antiangiogenic activity of Nutlin-3. Nutlin-3 did not inhibit established, mature blood vessels in the adult mouse retina, suggesting that only proliferating retinal vessels are sensitive to Nutlin-3. Furthermore, Nutlin-3 inhibited angiogenesis in nonretinal models such as the hind limb ischemia model. Our work demonstrates that Nutlin-3 functions through an antiproliferative pathway with conceivable advantages over existing cytokine-targeted antiangiogenesis therapies.
    The Journal of clinical investigation 09/2013; · 15.39 Impact Factor
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    ABSTRACT: Exploitation of embryonic stem cells (ESC) for therapeutic use and biomedical applications is severely hampered by the risk of teratocarcinoma formation. Here, we performed a screen of selected epi-modulating compounds and demonstrate that a transient exposure of mouse ESC to MS-275 (Entinostat), a class I histone deacetylase inhibitor (HDAC), modulates differentiation and prevents teratocarcinoma formation. Morphological and molecular data indicate that MS-275-primed ESCs are committed towards neural differentiation, which is supported by transcriptome analyses. Interestingly, in vitro withdrawal of MS-275 reverses the primed cells to the pluripotent state. In vivo, MS275-primed ES cells injected into recipient mice give only rise to benign teratomas but not teratocarcinomas with prevalence of neural-derived structures. In agreement, MS-275-primed ESC are unable to colonize blastocysts. These findings provide evidence that a transient alteration of acetylation alters the ESC fate.
    Biology open. 01/2013; 2(10):1070-7.
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    ABSTRACT: Metabolites are emerging as key mediators of crosstalk between metabolic flux, cellular signaling, and epigenetic regulation of cell fate. We found that the nonessential amino acid L-proline (L-Pro) acts as a signaling molecule that promotes the conversion of embryonic stem cells into mesenchymal-like, spindle-shaped, highly motile, invasive pluripotent stem cells. This embryonic-stem-cell-to-mesenchymal-like transition (esMT) is accompanied by a genome-wide remodeling of the H3K9 and H3K36 methylation status. Consistently, L-Pro-induced esMT is fully reversible either after L-Pro withdrawal or by addition of ascorbic acid (vitamin C), which in turn reduces H3K9 and H3K36 methylation, promoting a mesenchymal-like-to-embryonic-stem-cell transition (MesT). These findings suggest that L-Pro, which is produced by proteolytic remodeling of the extracellular matrix, may act as a microenvironmental cue to control stem cell behavior.
    Stem cell reports. 01/2013; 1(4):307-321.
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    ABSTRACT: The proangiogenic members of the vascular endothelial growth factor (VEGF) family and related receptors play a central role in the modulation of pathological angiogenesis. In order to identify plant compounds able to interfere in the VEGFs/VEGFR-1 (Flt-1) recognition by VEGF family members, the extracts of the aerial parts of Campsiandra guayanensis and Feretia apodanthera were screened by a competitive ELISA-based assay. By using this bioassay-oriented approach five proanthocyanindins, including the new natural compounds (2S)-4',5,7-trihydroxyflavan-(4β→8)-afzelechin (1) and (2S)-4',5,7-trihydroxyflavan-(4β→8)-epiafzelechin (2) and the known geranin B (3), proanthocyanidin A2 (4), and proanthocyanidin A1 (5), were isolated. The study of the antiangiogenic activities of compounds 1-5 using ELISA and SPR assays showed compound 1 as being the most active. The antiangiogenic activity of 1 was also confirmed in vivo by the chicken chorioallantoic membrane assay. Our results indicated 1 as a new antiangiogenic compound inhibiting the interaction between VEGF-A or PlGF and their receptor VEGRF-1.
    Journal of Natural Products 12/2012; · 3.29 Impact Factor
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    ABSTRACT: Purpose. Ocular neovascularization (NV), the primary cause of blindness, is typically treated via inhibition of vascular endothelial growth factor (VEGF) -A activity. However, besides VEGF-A, other proteins of the same family, including VEGF-B and placental growth factor (PlGF) (all together VEGFs), play a crucial role in the angiogenesis process. PlGF and VEGF, which form heterodimers if co-expressed, are both required for pathological angiogenesis. We generated a PlGF1 variant, named PlGF1-DE, which is unable to bind and activate VEGFR-1 but retains the ability to form heterodimer. PlGF1-DE acts as dominant negative of VEGF-A and PlGF1wt through heterodimerization mechanism. The purpose of this study was to explore the therapeutic potential of Plgf1-de gene in choroid and cornea neovascularization (NV) context. Methods. In the model of laser-induced choroid NV, Plgf1-de gene, and as control Plgf1wt, LacZ or gfp genes, were delivered using adeno associated virus (AAV) vector by subretinal injection, 14 days before the injury. After 7 day CNV volume was assessed. Corneal NV was induced by scrape or suture procedures. Expression vectors for PlGF1wt or PlGF1-DE, and as control the empty vector pCDNA3, were injected in the mouse cornea after the vascularization insults. NV was evaluated with CD31 and LYVE-1 immunostaining. Results. The expression of Plgf1-de induced significant inhibition of choroidal and corneal NV by reducing VEGF-A homodimer production. Conversely, the delivery of Plgf1wt, despite induced similar reduction of VEGF-A production, did not affect NV. Conclusions. Plgf1-de gene is a new therapeutic tool for the inhibition of VEGFs driven ocular NV.
    Investigative ophthalmology & visual science 11/2012; · 3.43 Impact Factor
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    ABSTRACT: Aging represents a major risk factor for vascular disease development. With aging, changes of the biological properties of vascular smooth muscle cells (SMCs) are observed. Stem marker expression characterizes SMCs during developmental growth and atherosclerosis, but the contribution of SMCs with stem features to the age-related arterial remodeling remains largely unknown. Immunostaining revealed rare vascular growth factor receptor-1(+) (flt-1(+)) and c-kit(+) cells in tunica media of grossly normal human young (17-30 years old) large arteries and 2-month old rat aorta, whereas CD133(+) cells were absent. In large arteries of human aged donors (64-77 years), flt-1(+) and c-kit(+) cell number increased in the intimal thickening and tunica media. Double immunofluorescence revealed that 30.6 ± 3% of flt-1(+) intimal cells co-expressed α-smooth muscle actin. Immunostaining, blots and RT-PCR documented the increased expression of flt-1 and c-kit in 20-24-month old rat aortic media. In vitro, old rat aortic SMCs proliferated and migrated more with greater flt-1, c-kit, NF-κB, VCAM-1, IAP-1 and MCP-1 levels and less α-smooth muscle actin and myosin compared to young SMCs. Old SMCs were also more susceptible to all-trans retinoic and NF-κB inhibition-induced apoptosis compared to young SMCs. Anti-flt-1 blocking antibody reduced migration and placental growth factor-induced but not serum and PDGF-BB-stimulated proliferation of old SMCs. The increase of flt-1(+) and c-kit(+) SMCs characterizes large arteries of aged donors; the blocking of flt-1 signaling influences the behavior of old SMCs, suggesting that the accumulation of SMCs with a stem phenotype contributes to the age-dependent adverse arterial remodeling.
    Atherosclerosis 07/2012; 224(1):51-7. · 3.71 Impact Factor
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    Sandro De Falco
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    ABSTRACT: Angiogenesis is a complex biological phenomenon crucial for a correct embryonic development and for post-natal growth. In adult life, it is a tightly regulated process confined to the uterus and ovary during the different phases of the menstrual cycle and to the heart and skeletal muscles after prolonged and sustained physical exercise. Conversly, angiogenesis is one of the major pathological changes associated with several complex diseases like cancer, atherosclerosis, arthritis, diabetic retinopathy and age-related macular degeneration. Among the several molecular players involved in angiogenesis, some members of VEGF family, VEGF-A, VEGF-B and placenta growth factor (PlGF), and the related receptors VEGF receptor 1 (VEGFR-1, also known as Flt-1) and VEGF receptor 2 (VEGFR-2, also known as Flk-1 in mice and KDR in human) have a decisive role. In this review, we describe the discovery and molecular characteristics of PlGF, and discuss the biological role of this growth factor in physiological and pathological conditions.
    Experimental and Molecular Medicine 01/2012; 44(1):1-9. · 2.57 Impact Factor
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    ABSTRACT: Angiogenesis is a crucial step in many pathological conditions like cancer, inflammation and metastasis formation; on these basis the search for antiangiogenic agents has widened. In order to identify new compounds able to interfere in the Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1, also known as Flt-1) recognition by VEGFs family members, we screened Calycolpus moritzianus (O. Berg) Burret leaves extracts by a competitive ELISA-based assay. MeOH and CHCl3 extracts and several their fractions demonstrated to be able to prevent VEGF or PlGF interaction with Flt-1, with an inhibition about 50% at concentration of 100 microg/mL. Phytochemical and pharmacological investigation of the active fractions led to the isolation of flavonoids, and terpenes.
    Natural product communications 07/2011; 6(7):943-6. · 0.96 Impact Factor
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    ABSTRACT: The use of Embryonic Stem Cells (ESCs) holds considerable promise both for drug discovery programs and the treatment of degenerative disorders in regenerative medicine approaches. Nevertheless, the successful use of ESCs is still limited by the lack of efficient control of ESC self-renewal and differentiation capabilities. In this context, the possibility to modulate ESC biological properties and to obtain homogenous populations of correctly specified cells will help developing physiologically relevant screens, designed for the identification of stem cell modulators. Here, we developed a high throughput screening-suitable ESC neural differentiation assay by exploiting the Cell(maker) robotic platform and demonstrated that neural progenies can be generated from ESCs in complete automation, with high standards of accuracy and reliability. Moreover, we performed a pilot screening providing proof of concept that this assay allows the identification of regulators of ESC neural differentiation in full automation.
    Molecular Biotechnology 05/2011; 50(3):171-80. · 2.26 Impact Factor
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    ABSTRACT: The proangiogenic members of VEGF family and related receptors play a central role in the modulation of pathological angiogenesis. Recent insights indicate that, due to the strict biochemical and functional relationship between VEGFs and related receptors, the development of a new generation of agents able to target contemporarily more than one member of VEGFs might amplify the antiangiogenic response representing an advantage in term of therapeutic outcome. To identify molecules that are able to prevent the interaction of VEGFs with related receptors, we have screened small molecule collections consisting of >100 plant extracts. Here, we report the isolation and identification from an extract of the Malian plant Chrozophora senegalensis of the biflavonoid amentoflavone as an antiangiogenic bioactive molecule. Amentoflavone can to bind VEGFs preventing the interaction and phosphorylation of VEGF receptor 1 and 2 (VEGFR-1,VEGFR-2) and to inhibit endothelial cell migration and capillary-like tube formation induced by VEGF-A or placental growth factor 1 (PlGF-1) at low μm concentration. In vivo, amentoflavone is able to inhibit VEGF-A-induced chorioallantoic membrane neovascularization as well as tumor growth and associated neovascularization, as assessed in orthotropic melanoma and xenograft colon carcinoma models. In addition structural studies performed on the amentoflavone·PlGF-1 complex have provided evidence that this biflavonoid effectively interacts with the growth factor area crucial for VEGFR-1 receptor recognition. In conclusion, our results demonstrate that amentoflavone represents an interesting new antiangiogenic molecule that is able to prevent the activity of proangiogenic VEGF family members and that the biflavonoid structure is a new chemical scaffold to develop powerful new antiangiogenic molecules.
    Journal of Biological Chemistry 04/2011; 286(22):19641-51. · 4.65 Impact Factor
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    ABSTRACT: The molecular mechanisms controlling mouse embryonic stem cell (ESC) metastability, i.e. their capacity to fluctuate between different states of pluripotency, are not fully resolved. We developed and used a novel automation platform, the Cell(maker), to screen a library of metabolites on two ESC-based phenotypic assays (i.e. proliferation and colony phenotype) and identified two metabolically related amino acids, namely l-proline (l-Pro) and l-ornithine (l-Orn), as key regulators of ESC metastability. Both compounds, but mainly l-Pro, force ESCs toward a novel epiblast stem cell (EpiSC)-like state, in a dose- and time-dependent manner. Unlike EpiSCs, l-Pro-induced cells (PiCs) contribute to chimeric embryos and rely on leukemia inhibitor factor (LIF) to self-renew. Furthermore, PiCs revert to ESCs or differentiate randomly upon removal of either l-Pro or LIF, respectively. Remarkably, PiC generation depends on both l-Pro metabolism (uptake and oxidation) and Fgf5 induction, and is strongly counteracted by antioxidants, mainly l-ascorbic acid (vitamin C, Vc). ESCs ↔ PiCs phenotypic transition thus represents a previously undefined dynamic equilibrium between pluripotent states, which can be unbalanced either toward an EpiSC-like or an ESC phenotype by l-Pro/l-Orn or Vc treatments, respectively. All together, our data provide evidence that ESC metastability can be regulated at a metabolic level.
    Journal of Molecular Cell Biology 02/2011; 3(2):108-22. · 7.31 Impact Factor
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    ABSTRACT: Combinatorial peptide libraries from synthetic or biological sources have been largely used in the last two-decades with the aim of identifying bioactive peptides that specifically bind proteins and modulate their interactions with other protein partners. Differently from biological libraries, synthetic methods allow the development of different kinds of libraries based on two main characteristics: i) the use of building blocks and chemical bonds different from those naturally occurring and ii) the possibility of designing scaffolds with non-linear shapes, as cyclic and branched structures. These two features, alone or in combination, have increased the chemical and structural diversity of peptide libraries expanding the offer of collections for the screenings. Here we describe our and other experiences with branched peptides and the results obtained in the last fifteen years. These clearly indicate how the use of short multimerized peptides can represent a successful approach for different applications ranging from affinity chromatography to the modulation of protein-protein interactions in different biological contexts.
    Current Medicinal Chemistry 01/2011; 18(16):2429-37. · 3.72 Impact Factor
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    Valeria Tarallo, Laura Tudisco, Sandro De Falco
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    ABSTRACT: Angiogenesis is one of the crucial events for cancer development and growth and vascular endothelial growth factor (VEGF) family plays an essential role in this biological phenomenon. The members of VEGF family mainly involved in angiogenesis are VEGF-A, VEGF-B and placental growth factor (PlGF), which exert their activity through the binding and activation of two VEGF receptors, VEGFR-1 and VEGFR-2. Human VEGF-A and PlGF are expressed in different isoforms and have the peculiarity to form heterodimer if co-expressed in the same cell. The difference of two main human PlGF isoforms, PlGF1 and PlGF2, consist in the exclusive ability of PlGF2 to bind heparin and Neuropilin receptors. As previously reported for PlGF1 isoform, we have generated a PlGF2 variant named PlGF2 -DE, in which the residues D(72) and E(73) were substituted with alanine, that is unable to bind and activate VEGFR-1 but is still able to heterodimerize with VEGF. Here we report that overexpression in VEGF-A producing human tumor cell line derived from ovarian carcinoma (A2780) of PlGF2-DE variant by stable transfection, significantly reduces the production of VEGF-A homodimer via heterodimerization, determining a strong inhibition of xenograft tumor growth and associated neoangiogenesis, as well as significant reduction of monocyte-macrophage infiltration. Conversely, the overexpression of PlGF2wt, also reducing the VEGF-A homodimer production comparably to PlGF2-DE variant through the generation of VEGF-A/PlGF2 heterodimer, does not inhibit tumor growth and vessel density compared to control, but induces increase of monocyte-macrophage infiltration. Interestingly the comparison of PlGF2wt with PlGF1wt overexpression evidences a significant reduction of monocyte-macrophages recruitment as unique difference among the activity of the two PlGFwt isoforms. Therefore, the 'less soluble' PlGF2 shows a limited potential in monocyte-macrophages recruitment. In conclusion data here reported demonstrate that PlGF-DE variant acts as 'dominant negative' of VEGF-A independently from the PlGF isoform utilized, that the expression of active PlGF2 homodimer and VEGF-A/PlGF2 heterodimer is sufficient to rescue pro-angiogenic activity lost for reduction of VEGF-A due to heterodimerization mechanism, and that PlGF2 shows lower activity into recruitment of monocyte-macrophage cells compared to PlGF1 isoform.
    American Journal of Cancer Research 01/2011; 1(2):265-274. · 2.65 Impact Factor
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    ABSTRACT: Cripto is a glycosylphosphatidylinositol-anchored coreceptor that binds Nodal and the activin type I (ALK)-4 receptor, and is involved in cardiac differentiation of mouse embryonic stem cells (mESCs). Interestingly, genetic ablation of cripto results in increased neuralization and midbrain dopaminergic (DA) differentiation of mESCs, as well as improved DA cell replacement therapy (CRT) in a model of Parkinson's disease (PD). In this study, we developed a Cripto specific blocking tool that would mimic the deletion of cripto, but could be easily applied to embryonic stem cell (ESC) lines without the need of genetic manipulation. We thus screened a combinatorial peptide library and identified a tetrameric tripeptide, Cripto blocking peptide (BP), which prevents Cripto/ALK-4 receptor interaction and interferes with Cripto signaling. Cripto BP treatment favored neuroectoderm formation and promoted midbrain DA neuron differentiation of mESCs in vitro and in vivo. Remarkably, Cripto BP-treated ESCs, when transplanted into the striatum of PD rats, enhanced functional recovery and reduced tumor formation, mimicking the effect of genetic ablation of cripto. We therefore suggest that specific blockers such as Cripto BP may be used to improve the differentiation of ESC-derived DA neurons in vitro and their engraftment in vivo, bringing us closer towards an application of ESCs in CRT.
    Stem Cells 08/2010; 28(8):1326-37. · 7.70 Impact Factor
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    ABSTRACT: The beneficial effect of the natural compound propionyl-l-carnitine (PLC) on intermittent claudication in patients with peripheral arterial disease is attributed to its anaplerotic function in ischemic tissues, but inadequate information is available concerning action on the vasculature. We investigated the effects of PLC in rabbit hind limb collateral vessels after femoral artery excision, mouse dorsal air pouch, chicken chorioallantoic membrane, and vascular cells by angiographic, Doppler flow, and histomorphometrical and biomolecular analyses. PLC injection accelerated hind limb blood flow recovery after 4 days (P<0.05) and increased angiographic quadriceps collateral vascularization after 7 days (P<0.001) Histomorphometry confirmed the increased vascular area (P<0.05), with unchanged intramuscular capillary density. PLC-induced dilatative adaptation, and growth was found associated with increased inducible nitric oxide synthase and reduced arterial vascular endothelial growth factor and intracellular adhesion molecule-1 expression. PLC also increased vascularization in air pouch and chorioallantoic membrane (P<0.05), particularly in large vessels. PLC increased endothelial and human umbilical vascular endothelial cell proliferation and rapidly reduced inducible nitric oxide synthase and NADPH-oxidase 4-mediated reactive oxygen species production in human umbilical vascular endothelial cells; NADPH-oxidase 4 also regulated NF-kappaB-independent intracellular adhesion molecule-1 expression. Our results provided strong evidence that PLC improves postischemic flow recovery and revascularization and reduces endothelial NADPH-oxidase-related superoxide production. We recommend that PLC should be included among therapeutic interventions that target endothelial function.
    Arteriosclerosis Thrombosis and Vascular Biology 03/2010; 30(3):426-35. · 6.34 Impact Factor
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    ABSTRACT: Angiogenesis is one of the crucial events for cancer development and growth. Two members of the vascular endothelial growth factor (VEGF) family, VEGF-A and placental growth factor (PlGF), which are able to heterodimerize if coexpressed in the same cell, are both required for pathologic angiogenesis. We have generated a PlGF1 variant, named PlGF1-DE in which the residues Asp72 and Glu73 were substituted with Ala, which is unable to bind and activate VEGF receptor-1 but is still able to heterodimerize with VEGF. Here, we show that overexpression in tumor cells by adenoviral delivery or stable transfection of PlGF1-DE variant significantly reduces the production of VEGF homodimer via heterodimerization, determining a strong inhibition of xenograft tumor growth and neoangiogenesis, as well as significant reduction of vessel lumen and stabilization, and monocyte-macrophage infiltration. Conversely, the overexpression of PlGF1wt, also reducing the VEGF homodimer production comparably with PlGF1-DE variant through the generation of VEGF/PlGF heterodimer, does not inhibit tumor growth and vessel density compared with controls but induces increase of vessel lumen, vessel stabilization, and monocyte-macrophage infiltration. The property of PlGF and VEGF-A to generate heterodimer represents a successful strategy to inhibit VEGF-dependent angiogenesis. The PlGF1-DE variant, and not PlGF1wt as previously reported, acts as a "dominant negative" of VEGF and is a new candidate for antiangiogenic gene therapy in cancer treatment.
    Cancer Research 02/2010; 70(5):1804-13. · 8.65 Impact Factor
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    ABSTRACT: To delineate the role of neuropilin-1 (NP-1), a vascular endothelial growth factor receptor (VEGFR), in rheumatoid inflammation and to determine whether blockade of NP-1 could suppress synoviocyte survival and angiogenesis. VEGF(111-165) peptide, which encompasses the NP-1 binding domain of VEGF(165), was generated by cleaving VEGF(165) with plasmin. The effect of this peptide on the interaction between VEGF(165) and its receptor was determined by (125)I-VEGFR binding assay. Assays to determine synoviocyte apoptosis, adhesion, and migration were performed in the presence of VEGF(165) and/or the peptide. VEGF(165)-induced angiogenesis was assessed by measuring the proliferation, tube formation, and wounding migration of endothelial cells (ECs). Mice were immunized with type II collagen to induce experimental arthritis. VEGF(111-165) peptide specifically inhibited the binding of (125)I-VEGF(165) to NP-1 on rheumatoid synoviocytes and ECs. The peptide eliminated the VEGF(165)-mediated increase in synoviocyte survival and activation of p-ERK and Bcl-2. The peptide also completely inhibited a VEGF(165)-induced increase in synoviocyte adhesion and migration. In addition, the anti-NP-1 peptide blocked VEGF(165)-stimulated proliferation, capillary tube formation, and wounding migration of ECs in vitro. VEGF(165)-induced neovascularization in a Matrigel plug in mice was also blocked by treatment with the peptide. Finally, subcutaneous injection of anti-NP-1 peptide suppressed arthritis severity and autoantibody formation in mice with experimental arthritis and inhibited synoviocyte hyperplasia and angiogenesis in arthritic joints. Anti-NP-1 peptide suppressed VEGF(165)-induced increases in synoviocyte survival and angiogenesis, and thereby blocked experimental arthritis. Our findings suggest that anti-NP-1 peptide could be useful in alleviating chronic arthritis.
    Arthritis & Rheumatology 01/2010; 62(1):179-90. · 7.48 Impact Factor

Publication Stats

763 Citations
238.10 Total Impact Points

Institutions

  • 2002–2012
    • National Research Council
      • • Institute of Genetics and Biophysics "Adriano Buzzati Traverso" IGB
      • • Institute of Plant Genetics IGV
      Roma, Latium, Italy
  • 2009
    • University of Kentucky
      • Department of Ophthalmology and Visual Sciences
      Lexington, KY, United States