1,720,978 research outputs found
Study on normal and tumoral cell subpopulations and their interactions in the mammary gland cancer of humans and animals
Get PDFHuman breast cancer (HBC), canine (CMT), and feline mammary tumors (FMT) are extremely common and are characterized by a remarkable both inter- and intra-tumor heterogeneity. Intra-tumor heterogeneity is due to the coexistence of cancer cells that differ between each other in terms of phenotypic, genetic, behavioral characteristics, and metastatic potential. Cancer stem cells (CSCs) are thought to be responsible for such heterogeneity, resistance to therapy, and metastasis development. Several pathways are altered in CSCs, such as the oncogenic Wnt/-catenin and Hippo pathways, and CSCs are associated to the epithelial-to-mesenchymal transition (EMT) process.
The aims of this study were to i) isolate and characterized mammary CSCs; ii) investigate EMT process and Wnt/-catenin and Hippo pathways in mammary cancer of the three species; iii) establish a metastatic mouse model of breast cancer seeking for genes responsible of metastatic dissemination; iv) isolate and characterize extracellular vesicles (EVs), which is one of the main forms of intercellular communication, from canine and feline mammary tumors as well as study the role that EVs play during tumor development.
CSC-like cells were isolated from established canine and feline mammary tumor cell lines (CYPp and FMCp, respectively) and phenotypically and molecularly characterized for common CSC markers: CD44, CD24, CD133, SOX2, OCT4. Moreover, gene (qPCR) and protein (IHC and WB) expression of Wnt/-catenin and Hippo pathways-related molecules (-catenin, CCND1, YAP, TAZ, CTGF, ANKRD1) as well as protein expression (IHC) of EMT-related molecules (E-cadherin, SNAIL, TWIST, ZEB) were evaluated in a subset of human, canine, and feline mammary cancer tissues, that were also phenotypically characterized for the following markers: CK8/18, CK5/6, CK14, CD44, and vimentin. Additionally, triple negative breast cancer (TNBC) cell line MDA-MB-231 was used to establish a clinically relevant in vivo metastatic model. Finally, EVs were isolated and characterized from CYPp and FMCp and human glioblastoma-derived EVs were used to study tumor angiogenesis.
We found that CD44, CD133, SOX2, and OCT4 expression increase in CSC-like cells (mammospheres) compared to parental adherent cells, therefore they could be used as useful markers in CMTs and FMTs. Wnt/-catenin and Hippo pathways seem to be deregulated at a post-transcriptional level in HBCs, CMTs, and FMTs. Interesting similarities were confirmed between TNBCs and FMTs, as well as between ER+ HBC and CMTs. In our metastatic model, mice developed distant metastases and we found a few genes that might play a role during metastatic dissemination. Among these, caspase 3 seems to be involved in brain metastases. Additionally, EVs were isolated from CYPp and FMCp, visualized by transmissible electron microscopy, counted using nanoparticle tracking analysis, and characterized by immunogold and WB (Alix, CD63, TSG101). Finally, using a human glioblastoma cell line (GBM8) we demonstrated that EVs are directly involved in tumor angiogenesis.
Overall, this study confirms the use of dogs and cats as spontaneous models of mammary cancer development due to highly interesting biological similarities among the three species. Also, identification of EVs in CMTs and FMTs opens an interesting unexplored field in veterinary medicine
Characterization and function of extracellular vesicles in a canine mammary tumour cell line: ultracentrifugation versus size exclusion chromatography
Get PDFExtracellular vesicles (EVs) are cell-derived membrane-bound vesicles involved in many biological processes such as tumour progression. For years, ultracentrifugation (UC) has been considered the gold standard for EV isolation but limited purity and integrity allowed the diffusion of alternative techniques. In this study, EVs were isolated from a canine mammary tumour cell line using UC and size exclusion chromatography (SEC) and analysed for size and concentration by nanoparticle tracking analysis (NTA) and for protein expression by western blot (WB). EV autocrine effect on cell proliferation, migration and invasiveness was then evaluated in vitro. In all samples, particles were in the EV size range (50-1000 nm), with a higher concentration in UC than in SEC samples (1011 and 1010 particles/ml respectively), and expressed EV markers (Alix, CD9). Functional assays did not show statistically significant difference among conditions, but EV treatment slightly increased cell proliferation and invasiveness and treatment with SEC-isolated EVs slightly enhanced cell migration compared to UC-isolated EVs. In conclusion, the main differences between the two isolation techniques are the quantity of the final EV-product and slight differences on EV functionality, which should be further explored to better highlight the real autocrine effect of tumoral EVs. This article is protected by copyright. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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