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Exossomos derivados de células dendríticas como adjuvantes naturais na resposta antitumoral. / Dendritic cells-derived exosomes as natural adjuvants in antitumor responses.Graziela Gorete Romagnoli 18 May 2012 (has links)
Exossomos (Exo) originados de células dendríticas (DCs) carregam moléculas associadas à apresentação antigênica. Neste trabalho procurou-se estabelecer se Exo de DCs seriam capazes de conferir imunogenicidade às células tumorais. Os Exo isolados de culturas de DCs expressavam as moléculas HLA-ABC, HLA-DR, CD86, CD11c, CD81, CD54 e CD18. Estes foram então adicionados às células da linhagem humana de adenocarcinoma mamário, SK-BR-3, as quais passaram a expressar as moléculas HLA-DR, CD86 e CD11c. As células tumorais modificadas pelos Exo induziram a produção de IL-6 e IL-10, detectados no sobrenadante das co-culturas destas com linfócitos T. Estas células tumorais também induziram aumento do número de linfócitos produtores de IFN-<font face=\"Symbol\">g, pré-sensibilizados contra antígenos tumorais, e aumento da expressão de SOCS3 nestes. Em conclusão, nossos resultados mostram que, Exo de DCs alteram o fenótipo de células tumorais, modificando sua interação com linfócitos T, sem induzir nas mesmas capacidade de ativar respostas proliferativas ou citotóxicas de linfócitos T in vitro. / Exosomes (Exo) originated from dendritic cells (DCs) contain molecules involved in antigen presentation. The present work sought to determine if Exo from DCs would be able to transfer immunogenicity to tumor cells. Exo isolated from DCs cultures carried HLA-ABC, HLA-DR, CD86, CD11c, CD81, CD54 and CD18. These Exo were added to cultures of the human breast adenocarcinoma cell line, SK-BR-3, which gained expression of HLA-DR, CD86 and CD11c. Tumor cells modified by Exo induced IL-6 and IL-10 production, detected in the supernatant of their co-cultures with T lymphocytes. These tumor cells also induced an increase in the frequency of IFN-<font face=\"Symbol\">g-producing T lymphocytes, pre-sensitized against tumor antigens, and an increased expression of SOCS3. In conclusion, our results show that, Exo from DCs affect the phenotype of tumor cells, modifying their interaction with T lymphocytes, without inducing the ability to activate cytotoxic or T cell proliferative responses in vitro.
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Engineered microsystems and their application in the culture and characterization of three-dimensional (3D) breast tumor modelsMenon, Nidhi 26 May 2021 (has links)
Microsystems are a broad category of engineered technologies in the micro and nano scale
that have a diverse range of applications. They are emerging as a powerful tool in the field
of biomedical research, drug discovery, as well as clinical diagnostics and prognostics, especially
with regards to cancer. One of the major challenges in precision and personalized
medicine in cancer lies in the technical difficulties of ex-vivo cell culture and propagation
of the limited number of primary cells derived from patients. Therefore, our aims are to
1. Develop a biologically relevant platform for culturing cancer cells and characterize how
it influences the cell growth and phenotype compared to conventional 2-dimensional(2D)
cell culturing techniques, 2. Isolate secondary metabolites from endophytic fungi and screen
them on the platform for potential anticancer properties in a preliminary drug discovery
pipeline, 3. Design and develop biosensors for quantifying cell responses in real-time within
these systems.
Several biomaterial scaffolds with microscale architectures have been utilized for engineering
the tumor extracellular matrix, but very few studies have thoroughly characterized the
phenotypic changes in their cell models, which is critical for translational applications of biomaterial
systems. The overall objective of these studies is to engineer a biomimetic platform
for the culture of breast cancer cells in vitro and to quantify and profile their phenotypic
changes. In order to do this, we first evaluated a blank-slate matrix consisting of thiolated
collagen, hyaluronic acid and heparin, cross-linked chemically via Michael addition reaction
using diacrylate functionalized poly (ethylene glycol). The hydrogel network was used with
triple-negative breast cancer cells and showed significant changes in characteristics, with
cells self-assembling to form a 3D spheroid morphology, with higher viability, and exhibiting
significantly lower cell death upon chemotherapy treatment, as well as had a decrease in proliferation.
Furthemore, the transcriptomic changes quantified using RNA-Seq and Next-Gen
Sequencing showed the dramatic changes in some of the commonly targeted pathways in cancer
therapy. Furthermore, we were able to show the importance of our biomimetic platform
in the process of drug discovery using fungal endophytes and their secondary metabolites as
the source for potential anticancer molecules. Additionally, we developed gold nanoparticle
and antibody-based (ICAM1 and CD11b) sensors to quantify cell responses spatiotemporally
on our platform. We were able to show quenching of the green fluorescent fluorophores due
to the Förster Resonance Energy Transfer mechanism between the fluorophore and the gold
nanometal surface. We also observed antigen-dependent recovery of fluorescence and inhibition
of energy transfer upon the antibody binding to the cell-surface receptors. Future efforts
are directed towards incorporating the hydrogel system with antigen-dependent sensors in a
conceptually-designed microfluidic platform to spatiotemporally quantify the expression of
surface proteins in various cells of the tumor stroma. This includes the migration,infiltration,
and polarization of specific immune cells. This approach will provide further insight into the
heterogeneity of cells at the single-cell resolution in defined spaces within the 3D microfluidic
platform. / Doctor of Philosophy / Microsystems are a broad category of engineered technologies in the micro and nano scale
that have a diverse range of applications. They are emerging as a powerful tool in the field
of biomedical research, drug discovery, as well as clinical diagnostics and prognostics, especially
with regards to cancer. However, a major challenge in being able to offer personalized
medicine to cancer patients comes from the difficulty of growing cells from the patient's
tumor biopsy in a laboratory for further screening and analysis. There are also limited resources
available for real-time expression of proteins on cell-surfaces, that could be potential
biomarkers and targets for treatment.
Various natural and synthetic polymers are biocompatible and have been used widely in
engineering the tumor extracellular matrix. However, the effect of hydrogels derived from
these polymers on the specific tumor cells are not always well characterized. Our studies
explore the influence of a biohybrid hydrogel on breast cancer cells and our results show that
the microscale architecture of the hydrogel platform works as a suitable scaffold for recapitulating
the 3-dimensional(3D) breast tumor microenvironment, and can also be employed in
the drug discovery process. Additionally, we developed a nano-scale biosensor to enable the
quantification of specific cell-surface proteins in real-time. Ongoing and future efforts are focused
on designing and fabricating a microfluidic device with precise control over the design
of space and special chambers for cell culture. These will be used for studying interactions of
various cells in the tumor microenvironment that influence cancer progression. Integrating
these micro-scale systems, including sensors will allow researchers to quantify cell behavior
in response to the variable factors they are exposed to, as well as provide insight to answer
fundamental questions about cancer biology that are limited by the conventional 2D cell
culture systems.
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Bicarbonate and dichloroacetate: Evaluating pH altering therapies in a mouse model for metastatic breast cancerRobey, Ian, Martin, Natasha January 2011 (has links)
BACKGROUND:The glycolytic nature of malignant tumors contributes to high levels of extracellular acidity in the tumor microenvironment. Tumor acidity is a driving force in invasion and metastases. Recently, it has been shown that buffering of extracellular acidity through systemic administration of oral bicarbonate can inhibit the spread of metastases in a mouse model for metastatic breast cancer. While these findings are compelling, recent assessments into the use of oral bicarbonate as a cancer intervention reveal limitations.METHODS:We posited that safety and efficacy of bicarbonate could be enhanced by dichloroacetate (DCA), a drug that selectively targets tumor cells and reduces extracellular acidity through inhibition of glycolysis. Using our mouse model for metastatic breast cancer (MDA-MB-231), we designed an interventional survival study where tumor bearing mice received bicarbonate, DCA, or DCA-bicarbonate (DB) therapies chronically.RESULTS:Dichloroacetate alone or in combination with bicarbonate did not increase systemic alkalosis in mice. Survival was longest in mice administered bicarbonate-based therapies. Primary tumor re-occurrence after surgeries is associated with survival rates. Although DB therapy did not significantly enhance oral bicarbonate, we did observe reduced pulmonary lesion diameters in this cohort. The DCA monotherapy was not effective in reducing tumor size or metastases or improving survival time. We provide in vitro evidence to suggest this outcome may be a function of hypoxia in the tumor microenvironment.CONCLUSIONS:DB combination therapy did not appear to enhance the effect of chronic oral bicarbonate. The anti-tumor effect of DCA may be dependent on the cancer model. Our studies suggest DCA efficacy is unpredictable as a cancer therapy and further studies are necessary to determine the role of this agent in the tumor microenvironment.
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The role of tumour necrosis factor alpha in pulmonary arterial hypertensionHurst, Liam Andrew January 2014 (has links)
No description available.
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The role of B cell activating factor in B cell development and autoimmunityZhang, Min, 張敏 January 2006 (has links)
published_or_final_version / abstract / Pathology / Doctoral / Doctor of Philosophy
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Investigation of biomarkers in esophageal squamous cell carcinomaChung, Man-fai, Yvonne., 鍾文暉. January 2009 (has links)
published_or_final_version / Surgery / Doctoral / Doctor of Philosophy
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TSG6 : expression and influence on the stability of the extracellular matrix in joint tissuesHowat, Sarah Lamont Telfer January 2000 (has links)
No description available.
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Alterations to the tumour suppressor genes p53 and dcc in colorectal neplasiaFroggatt, Nicola Jane January 1993 (has links)
No description available.
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Unique metabolic features of pancreatic cancer stroma: relevance to the tumor compartment, prognosis, and invasive potentialKnudsen, Erik S., Balaji, Uthra, Freinkman, Elizaveta, McCue, Peter, Witkiewicz, Agnieszka K. 07 November 2015 (has links)
Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. The aggressiveness and therapeutic recalcitrance of this malignancy has been attributed to multiple factors including the influence of an active desmoplastic stroma. How the stromal microenvironment of PDAC contributes to the fatal nature of this disease is not well defined. In the analysis of clinical specimens, we observed diverse expression of the hypoxic marker carbonic anhydrase IX and the lactate transporter MCT4 in the stromal compartment. These stromal features were associated with the epithelial to mesenchymal phenotype in PDAC tumor cells, and with shorter patient survival. Cultured cancer- associated fibroblasts (CAFs) derived from primary PDAC exhibited a high basal level of hypoxia inducible factor 1a (HIF1 alpha) that was both required and sufficient to modulate the expression of MCT4. This event was associated with increased transcription and protein synthesis of HIF1a in CAFs relative to PDAC cell lines, while surprisingly the protein turnover rate was equivalent. CAFs utilized glucose predominantly for glycolytic intermediates, whereas glutamine was the preferred metabolite for the TCA cycle. Unlike PDAC cell lines, CAFs were resistant to glucose withdrawal but sensitive to glutamine depletion. Consistent with the lack of reliance on glucose, CAFs could survive the acute depletion of MCT4. In co-culture and xenograft studies CAFs stimulated the invasive potential and metastatic spread of PDAC cell lines through a mechanism dependent on HIF1a and MCT4. Together, these data indicate that stromal metabolic features influence PDAC tumor cells to promote invasiveness and metastatic potential and associate with poor outcome in patients with PDAC.
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Role of VEGF-C in Proliferation and Migration in a Cancer ModelBenke, Emily Marie 01 January 2008 (has links)
Head and neck cancer ranks high among the most common cancers world wide. In addition, there is a high recurrence rate, as well as a high prevalence of loco-regional tumor spread. Among many factors contributing to metastasis is vascular endothelial cell growth factor C. VEGF-C is primarily an inducer of new lymph vessel formation, typically during embryogenesis; however, some advanced cancers show a significant increase in VEGF-C expression, suggesting a role in metastasis. In the current study, the effects of VEGF-C expression were tested in HN12 cells, which are highly metastatic and known to express high levels of the chemokine CXCL5. A connection between VEGF-C and CXCL5 expression was made in previous studies. VEGF-C expression was downregulated or upregulated in appropriate target cells, in order to test its effect on proliferation and migration. Downregulation of VEGF-C in HN12 cells resulted in a decrease in proliferation, migration and motility. Conversely, upregulation of VEGF-C in HN4 cells led to an increase in cell proliferation. In addition, downregulation of VEGF-C significantly lowered tumorigenicity in athymic mice. All results suggest VEGF-C is contributing to an increase in proliferation, migration and motility in this HNSCC model system.
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