No description available.

No description available.

No description available.

O HPV (Papilomavírus Humano) causa verrugas anogenitais e alguns tipos de câncer, como o câncer de colo do útero. Seu capsídeo é composto pelas proteínas L1 e L2. A L1 se autoestrutura em VLPs, utilizadas nas atuais vacinas comerciais. Para a geração de vacinas com maior espectro de proteção, a L2 é promissora, pois gera proteção cruzada. Para caracterizar VLPs de L1L2 do HPV16, células HEK293T cotransfectadas tiveram a expressão proteica analisada por citometria de fluxo, Western blotting, microscopia confocal a laser e eletrônica de transmissão. As proteínas L1 (60kDa) e L2 (100kDa) estavam presentes no núcleo e no citoplasma celular, formando VLPs de L1L2 de conformação heterogênea, cuja máxima expressão ocorre 12h após a transfecção. As VLPs extraídas estavam em diferentes estágios de estruturação. Foi possível estabelecer um sistema eficaz de produção heteróloga das proteínas de VLPs de L1L2, que poderão ser utilizadas em testes pré-clínicos, na pesquisa básica e contribuir no desenvolvimento de uma vacina profilática de amplo espectro de ação contra o HPV. / HPV (Human Papillomavirus) is the causative agent of anogenital warts and several types of cancer, as cervical cancer. The HPV capsid is composed of L1 and L2 proteins. L1 can self-assemble into VLPs (virus-like particles), the basis for HPV commercially available vaccines. To generate broad-spectrum vaccines L2 shows the greatest promise, due to cross-protection. To characterize VLPs composed of HPV16 L1 and L2 proteins, cotransfected HEK293T cells were analyzed by flow cytometry, confocal laser scanning microscopy, transmission electron microscopy and Western blotting. Proteins L1 (60kDa) and L2 (100kDa) were present in cell nucleus and cytoplasm, forming heterologous L1L2 VLPs with highest expression at 12h post-transfection. Extracted VLPs were at different maturation stages. It was possible to establish an efficient system of heterologous L1, L2 and L1L2 VLPs production. After some adjustments in protocols, these particles could be used in preclinical tests, HPV basic research and also in the development of an HPV broad-spectrum vaccine.

L’invasion cellulaire est un phénomène clé du développement tumoral au cours duquel les cellules réalisent une transition épithélio-mésenchymateuse (TEM) caractérisée par des changements d’expression de gènes clés dans la régulation de l’adhérence et de la morphologie cellulaire. L’expression de ces gènes est sous le contrôle de voies de signalisation, qui lors du processus de tumorigenèse sont dérégulées. La dérégulation de ces voies est multifactorielle et peut-être initiée par une activation de récepteurs présents à la membrane plasmique.Dans ce contexte, nous avons mis en évidence que les flotillines sont d’importants régulateurs de l’activation de ces récepteurs et des voies de signalisation en aval qui conduisent à l’induction de la TEM. Les flotillines 1 et 2 sont des protéines ubiquitaires très conservées. Le niveau d’expression des flotillines est accru dans de nombreux cancers invasifs et ceci est un facteur de mauvais pronostic. En condition physiologique, non surexprimées, les flotillines sont majoritairement à la membrane plasmique. Surexprimées les flotillines induisent la formation d’endolysosomes ayant une faible activité de dégradation, dans lesquels elles sont retrouvées.Mes travaux montrent que l’augmentation de l’expression des flotillines dans des cellules normales mammaires est suffisante pour induire le processus de TEM, processus clé de l’invasion tumorale. De plus nous montrons que la surexpression des flotillines génère une voie de trafic vésiculaire que nous nommons UFIT (Upregulated flotillin Induced Trafficking pathway) et qui affecte le trafic de plusieurs récepteurs membranaires connus pour participer à l’activation des voies oncogéniques inductrices de la TEM. Dans le cas particulier d’un de ces récepteurs, AXL, cible thérapeutique dans les cancers du sein, nous montrons que la surexpression des flotillines régule son endocytose et l’adresse dans les endosomes de signalisation riches en flotillines tout en le protégeant de la dégradation. Ces travaux apportent donc des explications nouvelles quant au rôle des flotillines dans le processus d’invasion cellulaire conduisant à la formation des métastases. / Tumor cell invasion and consecutive metastasis formation are the main cause of death in cancer patients. One crucial process of tumor cell invasion is the epithelial to mesenchymal transition (EMT), a reversible process during which polarized epithelial cells convert into motile mesenchymal cells. This process is characterized by gene expression changes involved, in particular, in the perturbation of cell adhesion, polarity and cytoskeletal structures.Flotillin 1 and 2 are two ubiquitous and highly conserved membrane proteins that assemble in large oligomers, known to participate in membrane protein clustering and endocytosis. Flotillins are upregulated in many invasive cancers and are considered as markers of poor prognosis. At physiological expression level, flotillins are mainly located at the plasma membrane. The cellular distribution of upregulated flotillins is dramatically modified with a strong enrichment in vesicular compartments that we characterized as non-degradative-endolysosomes.During my PhD project, we identified that flotillins are key EMT inducer. We upregulated flotillins in normal mammary cells and demonstrated that it is sufficient to promote EMT. Using several global comparative analyses (transcriptomic, phosphokinase arrays), we showed that flotillin upregulation activates key oncogenic signaling pathways and plasma membrane receptors. We identified that flotillin overexpression induces a trafficking pathway that we named UFIT-pathway (Upregulated flotillin Induced Trafficking pathway), which promotes the endocytosis of several cargos, amongst them membrane receptors involved in the activation of oncogenic pathways.Our results suggest that the UFIT pathway generates flotillin-positive endolysosomes acting as as “signalosome compartments” involved in the activation of signaling pathways stimulating EMT and cellular invasion.

This study consists of two pieces of work investigating haematological malignancies; Acute Lymphoblastic Leukaemia (ALL) and Diffuse Large B Cell Lymphoma (DLBCL). Firstly, Pre-B ALL represents the most common paediatric malignancy and despite increasingly improved outcomes for patients, ~ 20% of all patients diagnosed with ALL relapse. Activating mutations in the RAS pathway are common (~50%) and result in hyperactivation of the MAPK pathway. I identified Erk negative feedback control via DUSP6 to be crucial for NRASG12D-mediated pre-B cell transformation and investigated its potential as a therapeutic target. I showed that a small molecule inhibitor of DUSP6 (BCI) selectively induced cell death in patient-derived pre-B ALL cells; with a higher sensitivity observed in relapse pre-B ALL. I also discovered that a high level of Erk activity is required for proliferation of normal pre-B cells, but dispensable in leukemic pre-B ALL cells. In addition, I found that human B cell malignancies can be grouped into three categories that fundamentally differ in their ability to control Erk signalling strength. Secondly, DLBCL is the most common haematological malignancy and although potentially curable with chemotherapy, 40% of patients still succumb from their disease. Recent exome sequencing studies have identified hundreds of genetic alterations but, for most, their contribution to disease, or their importance as therapeutic targets, remains uncertain. I optimised a novel approach to screen the functional importance of these mutations. This was achieved by reconstituting non-malignant, primary, human germinal centre B cells (GC B cells) with combinations of wildtype and mutant genes to recapitulate the genetic events of DLBCL. When injected into immunodeficient mice, these oncogene-transduced GC B cells gave rise to tumours that closely resemble human DLBCL, reinforcing the biological relevance of this system. To screen potential tumour suppressor mutations in this system in a high throughput fashion, I developed a lymphoma-focused CRISPR library of 692 genes recurrently altered in B cell lymphomas. These experiments identified GNA13 as an unexpectedly potent tumour suppressor in human GC B cells and provided new understanding to its mechanism of action. These findings provide novel understanding of the complexity of oncogenic mechanisms in human B cell malignancies.

O Papilomavírus bovino (BPV) gera prejuízos à pecuária. O trabalho buscou isolar vírions de BPV de papilomas cutâneos previamente diagnosticados e avaliar o potencial clastogênico do vírus através do ensaio cometa (EC). O DNA tecidual foi extraído e submetido a PCR. As bandas foram purificadas e sequenciadas. As sequências foram analisadas através de bioinformática. A tipagem mostrou a prevalência de BPV-2. A análise histopatológica revelou acantose, coilocitose e hiperqueratose. Foi possível detectar a presença de fibroblastos transformados, sugerindo uma via de infecção através do sangue. A imuno-detecção das proteínas L1 e E7 no estroma sugere atividade transformadora do BPV em fibroblastos. O EC mostrou a ação clastogênica estatisticamente igual entre os tipos virais BPV-2, 5 e 9. O isolamento viral foi realizado através de ultracentrifugação em densidade única de cloreto de césio, empregando uma nova metodologia, que se mostrou menos laboriosa do que as já descritas, permitindo o isolamento de vírions de BPV-2, iniciando o banco de vírus proposto. / The Bovine papillomavirus (BPV) generates losses to livestock. The study sought to isolate BPV virions from cutaneous papillomas previously diagnosed and evaluate the clastogenic potential of the virus through the comet assay (EC). The tissue DNA was extracted and subjected to PCR. The bands were purified and sequenced. Sequences were analyzed using bioinformatics. The typing showed the prevalence of BPV-2. Histopathology showed acanthosis, hyperkeratosis and koilocytosis. It was possible to detect the presence of transformed fibroblasts, suggesting a route of infection through the blood. Immunohistochemical detection of L1 and E7 proteins in the stroma suggests transforming activity of BPV in fibroblasts. The EC clastogenic action showed statistically equal among the virus types BPV-2, 5 and 9. Viral isolation was performed by ultracentrifugation in a single cesium chloride density, using a new method that was less laborious than those already described, allowing the isolation of BPV-2 virions, starting the proposed stock virus.

O Papilomavírus bovino (BPV) gera prejuízos à pecuária. O trabalho buscou isolar vírions de BPV de papilomas cutâneos previamente diagnosticados e avaliar o potencial clastogênico do vírus através do ensaio cometa (EC). O DNA tecidual foi extraído e submetido a PCR. As bandas foram purificadas e sequenciadas. As sequências foram analisadas através de bioinformática. A tipagem mostrou a prevalência de BPV-2. A análise histopatológica revelou acantose, coilocitose e hiperqueratose. Foi possível detectar a presença de fibroblastos transformados, sugerindo uma via de infecção através do sangue. A imuno-detecção das proteínas L1 e E7 no estroma sugere atividade transformadora do BPV em fibroblastos. O EC mostrou a ação clastogênica estatisticamente igual entre os tipos virais BPV-2, 5 e 9. O isolamento viral foi realizado através de ultracentrifugação em densidade única de cloreto de césio, empregando uma nova metodologia, que se mostrou menos laboriosa do que as já descritas, permitindo o isolamento de vírions de BPV-2, iniciando o banco de vírus proposto. / The Bovine papillomavirus (BPV) generates losses to livestock. The study sought to isolate BPV virions from cutaneous papillomas previously diagnosed and evaluate the clastogenic potential of the virus through the comet assay (EC). The tissue DNA was extracted and subjected to PCR. The bands were purified and sequenced. Sequences were analyzed using bioinformatics. The typing showed the prevalence of BPV-2. Histopathology showed acanthosis, hyperkeratosis and koilocytosis. It was possible to detect the presence of transformed fibroblasts, suggesting a route of infection through the blood. Immunohistochemical detection of L1 and E7 proteins in the stroma suggests transforming activity of BPV in fibroblasts. The EC clastogenic action showed statistically equal among the virus types BPV-2, 5 and 9. Viral isolation was performed by ultracentrifugation in a single cesium chloride density, using a new method that was less laborious than those already described, allowing the isolation of BPV-2 virions, starting the proposed stock virus.

O HPV (Papilomavírus Humano) causa verrugas anogenitais e alguns tipos de câncer, como o câncer de colo do útero. Seu capsídeo é composto pelas proteínas L1 e L2. A L1 se autoestrutura em VLPs, utilizadas nas atuais vacinas comerciais. Para a geração de vacinas com maior espectro de proteção, a L2 é promissora, pois gera proteção cruzada. Para caracterizar VLPs de L1L2 do HPV16, células HEK293T cotransfectadas tiveram a expressão proteica analisada por citometria de fluxo, Western blotting, microscopia confocal a laser e eletrônica de transmissão. As proteínas L1 (60kDa) e L2 (100kDa) estavam presentes no núcleo e no citoplasma celular, formando VLPs de L1L2 de conformação heterogênea, cuja máxima expressão ocorre 12h após a transfecção. As VLPs extraídas estavam em diferentes estágios de estruturação. Foi possível estabelecer um sistema eficaz de produção heteróloga das proteínas de VLPs de L1L2, que poderão ser utilizadas em testes pré-clínicos, na pesquisa básica e contribuir no desenvolvimento de uma vacina profilática de amplo espectro de ação contra o HPV. / HPV (Human Papillomavirus) is the causative agent of anogenital warts and several types of cancer, as cervical cancer. The HPV capsid is composed of L1 and L2 proteins. L1 can self-assemble into VLPs (virus-like particles), the basis for HPV commercially available vaccines. To generate broad-spectrum vaccines L2 shows the greatest promise, due to cross-protection. To characterize VLPs composed of HPV16 L1 and L2 proteins, cotransfected HEK293T cells were analyzed by flow cytometry, confocal laser scanning microscopy, transmission electron microscopy and Western blotting. Proteins L1 (60kDa) and L2 (100kDa) were present in cell nucleus and cytoplasm, forming heterologous L1L2 VLPs with highest expression at 12h post-transfection. Extracted VLPs were at different maturation stages. It was possible to establish an efficient system of heterologous L1, L2 and L1L2 VLPs production. After some adjustments in protocols, these particles could be used in preclinical tests, HPV basic research and also in the development of an HPV broad-spectrum vaccine.

No description available.