1,720,967 research outputs found
Stromal delivery of long Pentraxin-3 impairs FGF/FGFR-dependent tumor growth and metastasis
No full textThe FGF/FGFR system contributes to cancer progression by inducing tumor growth and neovascularization, thus representing an emerging therapeutic target. Long Pentraxin-3 (PTX3) is a soluble pattern recognition receptor expressed by endothelial and immune cells in inflammatory contexts. Among various ligands, PTX3 binds different members of the FGF family, acting as a natural FGF ligand trap.
Here, we generated transgenic mice expressing human (h)PTX3 under the control of endothelial specific Tie2/Tek transcription regulatory sequences (Tie2-hPTX3 mice). These animals accumulate significant levels of hPTX3 in perivascular stroma and in the blood stream. On this basis, Tie2-hPTX3 mice were used to investigate the impact of stroma delivery of hPTX3 on tumor growth, vascularization and metastasis.
The anti-angiogenic activity of endothelium-derived hPTX3 was confirmed by ex vivo aorta ring and in vivo matrigel plug assays. Next, different syngeneic FGF-dependent tumor cell lines, including TRAMP-C2 prostate carcinoma, B16-F10 melanoma and Lewis Lung carcinoma cells, were subcutaneously injected in Tie2-hPTX3 mice. Notably, the growth of all tumor grafts was significantly reduced in Tie2-hPTX3 mice when compared to wild type animals and was accompanied by a significant reduction of FGFR1 phosphorylation, decrease of tumor vascularity and tumor cell proliferation. Also, B16-F10 melanoma and M5076 ovarian sarcoma cells showed a dramatic decrease of their capacity to form experimental metastases in the lung and liver, respectively, after intravenous injection in Tie2-hPTX3 mice. Also, the orthotopic growth of syngeneic pancreatic and mammary tumor cells was significantly reduced after injection in Tie2-hPTX3 mice and led to increased survival compared to control mice. Finally, double transgenic TRAMP/Tie2-hPTX3 mice showed a significant delay of multistage prostate tumor onset and progression in respect to TRAMP mice.
Our findings demonstrate for the first time that in vivo delivery of PTX3 exerts a dramatic impact on tumor growth, vascularization and metastasis. These results have set the basis for the identification of a low molecular weight PTX3-derived molecule that recapitulates the FGF-trap activities of PTX3 and exhibits promising therapeutic potential for FGF-dependent tumors
Matrigel plug assay: evaluation of the angiogenic response by reverse transcription-quantitative PCR
No full textThe subcutaneous Matrigel plug assay in mice
is a method of choice for the in vivo evaluation of pro- and
anti-angiogenic molecules. However, quantification of the
angiogenic response in the plug remains a problematic task.
Here we report a simple, rapid, unbiased and reverse
transcription-quantitative PCR (RT-qPCR) method to
investigate the angiogenic process occurring in the Matrigel
plug in response to fibroblast growth factor-2 (FGF2).
To this purpose, a fixed amount of human cells were added
to harvested plugs at the end of the in vivo experimentation
as an external cell tracer. Then, mRNA levels of the panendothelial
cell markers murine CD31 and vascular
endothelial-cadherin were measured by species-specific
RT-qPCR analysis of the total RNA and data were normalized
for human GAPDH or b-actin mRNA levels. RTqPCR
was used also to measure the levels of expression in
the plug of various angiogenesis/inflammation-related
genes. The procedure allows the simultaneous, quantitative
evaluation of the newly-formed endothelium and of nonendothelial/
inflammatory components of the cellular infiltrate
in the Matrigel implant, as well as the expression of
genes involved in the modulation of the angiogenesis
process. Also, the method consents the quantitative
assessment of the effect of local or systemic administration
of anti-angiogenic compounds on the neovascular response
triggered by FGF
Stromal expression of long Pentraxin-3 impairs tumor growth and metastasis
No full textLong Pentraxin-3 (PTX3) is a soluble pattern recognition receptor expressed by endothelial and immune cells in inflammatory contexts. We have previously demonstrated that PTX3 binds to different members of the FGF family, thus inhibiting their biological activity. The FGF/FGFR system strongly contributes to cancer progression by inducing tumor growth and neovascularization. To date, recombinant PTX3 protein or PTX3-overexpressing tumor cell lines have been exploited to assess the antitumor effects of this natural FGF trap. Here we generated C57BL/6 transgenic mice expressing human (h)PTX3 under the control of the endothelial specific Tie2/Tek transcription regulatory sequences. These animals were used to investigate the impact of PTX3 overexpression by the host stroma on tumor growth, vascularization and metastasis.
Transgenic Tie2-hPTX3 mice were generated by cloning the hPTX3 cDNA into the late-generation, self-inactivating lentiviral vector Tie2p/e to obtain the Tie2-hPTX3 lentiviral transfer vectors that were injected into fertilized oocytes. Expression of the transgene was confirmed by RT-PCR and western blot analyses of different organs from Tie2-hPTX3 mice that showed increased levels of circulating PTX3 (80-180 ng/ml) when compared to wild type (wt) animals (<1.8 ng/ml). Also, histological analysis confirmed the perivascular accumulation of hPTX3 in transgenic animals. To assess the anti-angiogenic activity of endothelium-derived hPTX3, we performed ex vivo aorta ring and in vivo matrigel plug assays. Both assays revealed a significant inhibition of FGF2-driven angiogenesis in Tie2-hPTX3 mice that maintained their responsiveness to VEGF-A, thus confirming the specificity of the effect. Next, different syngeneic FGF-dependent tumor cell lines, including TRAMP-C2 prostate carcinoma, B16-F10 melanoma and Lewis Lung carcinoma cells, were subcutaneously injected in Tie2-hPTX3 mice. Notably, the growth of all tumor grafts was significantly reduced in Tie2-hPTX3 mice when compared to wt animals. Also, histological analysis of TRAMP-C2 tumors grown in Tie2-hPTX3 mice showed a strong perivascular expression of hPTX3 and a significant reduction of FGFR1 phosphorylation. This was paralleled by a significant decrease of tumor vascularity and tumor cell proliferation whereas no difference in tumor growth was observed for TRAMP-C2 grafts expressing a constitutively activated form of FGFR1. Finally, B16-F10 melanoma and M5076 ovarian sarcoma cells showed a dramatic decrease of their capacity to form experimental metastases in the lung and liver, respectively, after intravenous injection in Tie2-hPTX3 mice.
PTX3 is a natural FGF ligand trap. Our findings demonstrate for the first time that the production of PTX3 by the host stroma may exert a dramatic impact on tumor growth, vascularization and metastasis with potential exploitation for the therapy of FGF-dependent tumors
The pattern recognition receptor PTX3 as an angiostatic epithelial/stromal FGF-targeting inhibitor in hormonal cancers
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Long pentraxin-3 inhibits epithelial-mesenchymal transition in melanoma cells.
No full textDuring melanoma progression, malignant melanocytes are reprogrammed into mesenchymal-like cells through to an epithelial-mesenchymal transition (EMT) process associated with the acquisition of an invasive, prometastatic phenotype. The fibroblast growth factor-2 (FGF2)/FGF receptor (FGFR) system plays a pivotal role in melanoma, leading to autocrine/paracrine induction of tumor cell proliferation and angiogenesis. Long pentraxin-3 (PTX3) interacts with FGF2, and other FGF family members, inhibiting FGF-dependent neovascularization and tumor growth. Here, PTX3 protein and the PTX3-derived acetylated pentapeptide Ac-ARPCA-NH2 inhibit FGF2-driven proliferation and downstream FGFR signaling in murine melanoma B16-F10 cells. Moreover, human PTX3-overexpressing hPTX_B16-F10 cells are characterized by the reversed transition from a mesenchymal to an epithelial-like appearance, inhibition of cell proliferation, loss of clonogenic potential, reduced motility and invasive capacity, downregulation of various mesenchymal markers, and upregulation of the epithelial marker E-cadherin. Accordingly, PTX3 affects cell proliferation and EMT transition in human A375 and A2058 melanoma cells. Also, hPTX_B16-F10 cells showed a reduced tumorigenic and metastatic activity in syngeneic C57BL/6 mice. In conclusion, PTX3 inhibits FGF/FGFR-driven EMT in melanoma cells, hampering their tumorigenic and metastatic potential. These data represent the first experimental evidence about a nonredundant role of the FGF/FGFR system in the modulation of the EMT process in melanoma and indicate that PTX3 or its derivatives may represent the basis for the design of novel therapeutic approaches in FGF/FGFR-dependent tumors, including melanoma
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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