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Molecular mediators of alpha v beta 3-induced NF-[kappa] B activation in endothelial cell survival /Rice, Julie Ann. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 102-123).
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Modelo de compressão contínua na cultura de fibroblastos derivados do ligamento periodontal humano / Continuous compression model in fibroblast culture derived from human periodontal ligamentMattar, Marco Antonio [UNIFESP] January 2015 (has links) (PDF)
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Previous issue date: 2015 / Introdução: Modelos de estudos in vitro são considerados como padrão
ouro para análises de atividades celulares que visam mimetizações da
dinâmica das células in vivo, inclusive quando as amostras celulares são submetidas à compressão estática. Células quando cultivadas sob um
substrato representam a estrutura natural e função dos tecidos in vivo no
que diz respeito à fisiologia, forma da célula e seu ambiente. Objetivo:
Avaliar a viabilidade e morte celular no modelo de compressão contínua na
cultura de fibroblastos humanos derivados do ligamento periodontal.
Métodos: Foram selecionados 10 pacientes, submetidos à extrações dos 4
terceiros molares inclusos por indicação ortodôntica. A amostra consistiu
de 4 mm2 de tecido periodontal do terço médio das raízes. A mesma foi
cultivada até a 6ª passagem e depois as células foram divididas em dois
grupos: Grupo Controle (GC), com cultivo em monocamada e substrato
sem aplicação de força durante 6h e Grupo Experimental (GE3 e GE4),
com cultivo em monocamada e substrato com aplicação de carga de 3 e 4
g/cm2 durante 6h. Resultados: Tanto o GC quanto o GE3 e GE4,
monocamada e substrato, não apresentaram diferença estatística nos valores
de viabilidade celular e apoptose. Com o aumento da carga o GE4 indicou
maior necrose em relação ao GC e o GE3. Conclusão: Não houve
diferença na utilização de substrato de colágeno na cultura de fibroblastos
periodontais em nenhum dos parâmetros avaliados, mas houve maior
necrose com o aumento da carga na avaliação intragrupos. Descritores: Ligamento periodontal, Sobrevivência celular, Apoptose, Técnicas de cultura de células. / Introduction: In vitro studies of models are considered as gold standard
for cell analysis activities aimed mimetics of the dynamics of cells in vivo, even when the cell samples are subjected to static compression. Cells when grown in a substrate represent the natural structure and function of tissues
in vivo with respect to physiology, cell shape and its environment.
Objective: To evaluate the viability and cell death in the pressure model
continues the culture of fibroblasts derived from human periodontal
ligament. Methods: We selected 10 patients who underwent extractions of
4 the 3rd molars included for orthodontic indication. The sample consisted
of 4 mm2 of periodontal tissue of the middle third of the roots. The same
was grown to the 6th passage, then the cells were divided into two groups:
the Control Group (CG) with culture monolayer and the substrate without
application of force for 6h and Experimental Group (EG3, EG4) with
growing monolayer and substrate 3 of load application and 4 g/cm2 for 6
hours. Results: Both the CG when the EG3 and EG4, monolayer and
substrate showed no statistical difference in cell viability and apoptosis
values. With increasing load the EG4 indicated greater necrosis than the
CG and EG3. Conclusion: There was no difference in the use of collagen
substrate in the culture of periodontal fibroblasts in all evaluated
parameters, but there was a higher necrosis with increasing load on the
intra-group evaluation.
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Estudo da viabilidade celular comparando os meios de conservação para enxerto ósseo de calota craniana : análise microscópica e imunoistoquímica em ratos /Tanaka, Fábio Yoshio. January 2005 (has links)
Resumo: O objetivo deste trabalho foi analisar a viabilidade celular comparando os meios de conservação para enxerto ósseo. A preservação de células viáveis em procedimentos de enxerto ósseo é de fundamental importância para que se tenha a osteogênese. Foram utilizados 43 ratos machos. Após a antissepsia do campo operatório foi realizada incisão linear na região mediana da calota craniana para obtenção do enxerto da região parietal direita e esquerda as quais foram removidas com auxílio de trefina de 5mm de diâmetro acoplada em micro-motor de baixa rotação, sob constante irrigação com solução de soro fisiológico 0,9% estéril. As peças do enxerto foram acondicionadas em tubos de ensaio estéreis os quais foram devidamente identificadas de acordo com o grupo e mantidas dentro deste tubo conforme cada condição do grupo. Como meio de conservação da viabilidade celular do enxerto foi utilizado o soro fisiológico a 0,9% (Grupo I) e a solução de Euro Collins® (Grupo II) e ainda para verificar se a temperatura tem influência direta na manutenção da viabilidade celular foi analisado o enxerto ósseo conservado em temperatura ambiente (Grupo III) e o enxerto ósseo sem nenhuma solução, porém mantido em gelo (GrupoIV). Para avaliar a viabilidade celular foi utilizada análise histológica e imunoistoquímica imediata e ainda em cada grupo analisou-se a viabilidade celular no período de 6 horas, 12 horas, 24 horas e 30 horas. Como resultado observou-se que a solução de Euro Collins® apresentou-se superior ao soro fisiológico no que se diz respeito à manutenção da viabilidade celular do enxerto ósseo onde se pode notar viabilidade celular até o período de 30 horas. / Abstract: The aim of this study was to analyze cellular viability comparing storage media for skull vault bone graft. Preservation of viable cells in bone graft procedures is of paramount importance to obtain osteogenesis. Forty-three male used in this study. After antisepsis of the operative field, a linear incision was made on the middle region of the skull vault to obtain a bone graft from the right and left parietal areas. The grafts were removed with a 5-mm diameter trephine bur coupled to low-speed handpiece under continuous irrigation with sterile 0.9% saline. The graft pieces were placed in sterile 5-mL test tubes with caps, and were properly identified according to the group and maintained inside the test tubes as per each group conditions. The storage media evaluated for preservation of graft cellular viability were 0.9% saline (Group I) and Euro Collins® solution (Group II). In order to assess whether the temperature has a direct influence on the maintenance of cellular viability, the analysis was extended to bone grafts stored at room temperature (Group III) and bone grafts with no solution, but maintained in ice (Group IV). Cellular viability was evaluated by immediate histological and immunohistochemical analyses. For each group, cellular viability was analyzed at 6, 12, 24 and 30 hours after procedure. The results of this study showed that Euro Collins® solution yielded better performance than 0.9% saline as regards the maintenance of bone graft cellular viability (up to 30 hours). / Orientador: Tetuo Okamoto / Coorientador: Roberta Okamoto / Banca: Luis Eduardo Marques Padovan / Banca: Hugo Nery Filho / Banca: Celso Koogi Sonoda / Banca: Idelmo Rangel Garcia Júnior / Banca: Wilson Roberto Poi / Doutor
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Estudo do papel do sistema de captação de fosfato inorgânico (Pst) na fisiologia e patogênese de Streptococcus mutans. / Study of the role of inorganic phosphate uptake system (Pst) in the physiology and pathogenesis of Streptococcus mutans.Daniela Eleuterio da Luz 28 January 2011 (has links)
O fosfato inorgânico é um composto essencial por estar relacionado com diversos processos metabólicos e biossíntese de moléculas relevantes à sobrevivência celular. Em bactéria são conhecidos dois tipos principais de transportadores específicos de fosfato inorgânico, o sistema Pit, de baixa afinidade, e o sistema Pst de alta afinidade, um ABC transportador, ativado sob carência de fosfato extracelular. A interação deste sistema com a fisiologia e patogênese de Streptococcus mutans, o principal agente etiológico da cárie dental, foi estudada neste trabalho. Os genes que codificam o sistema Pst de S. mutans UA159, estão organizados em um óperon policistrônico (pstS, C1, C, B, smu.1134 e phoU). A análise das sequências de aminoácidos das proteínas do sistema Pst de S. mutans com ortólogos do gênero Streptococcus, demonstrou maior identidade com bactérias da cavidade oral. Análise de prevalência do gene pstS, que codifica a proteína ligadora, demonstrou conservação entre todas as cepas laboratoriais e clínicas avaliadas. A deleção de pstS reduziu a capacidade de incorporação de ortofosfato que se refletiu na diminuição da taxa de replicação celular em meios com diferentes concentrações de fosfato inorgânico. A mutação também reduziu a capacidade da bactéria em aderir à superfícies abióticas e diminuiu sua hidrofobicidade de superfície, além de aumentar a resistência intrínseca a ácido. No entanto, não houve alteração na eficiência de transformação bacteriana. Por fim, o gene pstS de S. mutans foi clonado, expresso e a proteína purificada utilizada para obter anticorpos que inibiram o crescimento de S. mutans in vitro. Deste modo, segere-se que o sistema Pst é relevante na fisiologia e patogênese de S. mutans. / Inorganic phosphate is an essential compound related to several metabolic process and biosynthesis of molecules relevant to cellular survival. Bacteria are known to posses two main types of specific inorganic phosphate transporters, the low-affinity Pit system, and the high affinity Pst system, an ABC transporter family constituent, activated by extracellular phosphate starvation. The aim of this work was to study the role of Pst system in physiology and pathogenesis of Streptococcus mutans, the main etiological agent of dental caries. The genes of the Pst system of S. mutans UA159, are organized in a polycistronic operon (pstS, C1, C, B, smu.1134 and phoU). The amino acid sequence analysis of Pst proteins of S. mutans related to orthologs of Streptococcus genus, showed the highest identity value when compared to oral cavity bacteria. The PstS binding protein was present in all tested clinical and laboratory strains of S. mutans. The pstS mutant showed a decreased capacity of ortophosphate uptake which leaded to growth deficiency in different phosphate concentrations. The mutation also reduced the bacteria adherence to abiotic surfaces and the hydrophobicity of the cell surface, diverging from the increase the intrinsic acid resistance. Otherwise, there was no change in the bacterial transformation eficiency. Finally, the S. mutans pstS gene was cloned, expressed and the purified protein was used to obtain antibodies that inhibited the growth of S. mutans in vitro. Taking together, these results suggesting that the Pst transport system is relevant to S. mutans physiology and pathogenesis.
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Efeitos da articaína livre e associada a lipossomas com gradiente de pH transmembranar sobre a viabilidade celular e expressão de IL-6 em queratinócitos humanos (HaCaT) : The effects of plain and liposome-associated articaine with transmembrane pH gradient on humam keratinocytes (HaCaT) viability and IL-6 expression / The effects of plain and liposome-associated articaine with transmembrane pH gradient on humam keratinocytes (HaCaT) viability and IL-6 expressionMuniz, Bruno Vilela, 1988- 24 August 2018 (has links)
Orientadores: Maria Cristina Volpato, Francisco Carlos Groppo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-24T18:59:54Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: A articaína não encapsula em proporção significativa em lipossomas sem gradiente de pH transmembranar. O objetivo deste estudo foi preparar e realizar a caracterização inicial de formulação de articaína associada a lipossomas unilamelares (400nm) com gradiente de pH transmembranar, com sulfato de amônia como tampão interno sobre a viabilidade celular em culturas de queratinócitos humanos (HaCaT) e sobre a liberação de uma interleucina pró-inflamatória (IL-6), comparando com formulações de articaína livre. As células foram expostas às formulações de articaína nas concentrações 0,1%, 0,2% e 0,3% na forma de solução e em suspensão lipossomal (lipossomas unilamelares), além dos controles (soro fisiológico, suspensão lipossomal e meio de cultura). A avaliação da viabilidade celular (redução do MTT - espectrofotometria) foi realizada após 10 min e 4h e a quantificação da IL-6 (imunoensaio de ELISA) após 4h da exposição às formulações. Os resultados foram submetidos aos testes de Kruskal-Wallis com post-hoc de Dunn (viabilidade celular) e de Student-Newman-Keuls (IL-6) com significância de 5%. As vesículas lipossomais mantiveram-se integras após a encapsulação de articaína, apresentando 18,95% de eficiência de encapsulação. A polidispersão dos lipossomas sem anestésico foi de 0,2 ± 0,0, enquanto a dos liposomas contendo articaína variou de 0,56 ± 0,03 a 0,66 ± 0,10. O potencial Zeta variou de -10,5 ± 0,9 a -21,2 ± 0,9 mV. O tamanho das vesículas variou de 622 ± 71,5 a 796 ± 111,95 nm. A viabilidade celular foi diminuída após 10 min de exposição às formulações lipossomais (com e sem articaína) em relação aos demais tratamentos (p<0,05); as formulações lipossomais não diferiram entre si (p>0,05). Não houve diferenças entre os demais tratamentos (p>0,05), os quais não alteraram a viabilidade nesse tempo de exposição. Após exposição por 4h houve diminuição na viabilidade em todas as formulações lipossomais e nas formulações de articaína livre 0,2% e 0,3% (p<0,05), à exceção dos grupos controle e articaína 0,1% (p>0,05). A liberação de IL-6 não foi afetada pelas formulações lipossomais (p>0,05); a articaína livre em todas as concentrações testadas aumentou a liberação de IL-6, tanto em relação ao controle, quanto às formulações lipossomais com a mesma concentração de articaína (p<0,05). Conclui-se que a utilização de lipossomas com gradiente de pH transmembranar aumentou a encapsulação de articaína, entretanto, apresentou toxicidade intrínseca no modelo avaliado / Abstract: Articaine is not encapsulated in significant proportion in liposomes without transmembrane pH gradient. The aim of this study was to perform the initial characterization of a formulation of articaine in unilamelar liposome with transmembranarpH gradient and to observe its effects on human keratinocytes (HaCaT) regarding cellular viability and liberation of interleukin 6 (IL-6) in comparison to plain articaine. HaCaT cells were exposed to plain articaine solutions and liposomal suspensions (0.1%, 0.2% and 0.3% articaine concentrations) and to the controls (saline, liposomal suspension and culture medium). Cell viability (MTT reduction - spectrophotometry) was evaluated at 10 min and 4h after exposure to the treatments; IL-6 was determined after 4 h of cell treatments. Cell viability results were submitted to Kruskal-Wallis test, followed by Dunn post-hoc test; IL-6 results were analyzed by Kruskal-Wallis and Student-Newman-Keuls tests. Significance was set at 5%. Liposome vesicles remained intact after articaine loading and presented encapsulation efficiency of 18.95%. Liposome without anesthetic presented polydispersity index of 0.2 ± 0.0, while liposomes with articaine showed values of 0.56 ± 0.03 to 0.66 ± 0.10. Zeta potentials varied from -10.5 ±0.9 to -21.2 ± 0.9 mV and vesicle sizes from 622 ± 71.5 to 796 ± 111.95 nm. Cell viability decreased after 10 min exposure to the liposomal formulations (with and without articaine) in relation to the other treatments (p<0.05); liposomal formulations did not differ from each other (p>0.05). No differences were found among the other treatments (p>0.05), which did not interfere in cell viability after this exposure time. After 4h exposure cell viability was diminished by all liposomal formulations and by 0.2% and 0.3% plain articaine (p<0.05), except for control groups and 0.1% plain articaine (p>0.05). IL-6 release was not affected by liposomal formulations (p>0.05); all concentrations of plain articaine increased IL-6 release in relation to the controls and to each correspondent liposomal formulation (p<0.05). In conclusion, liposome with transmembrane pH gradient increases articaine encapsulation in relation to that described in the literature, however it presented intrinsic in the model evaluated / Mestrado / Farmacologia, Anestesiologia e Terapeutica / Mestre em Odontologia
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Estudo dos subtipos celulares do sangue de cordão umbilical e sua viabilidade antes do processamento e após o descongelamento = armazenamento à temperatura ambiente por 96 horas =Study of umbilical cord blood cell subtypes and its viability prefreezing and post-thaw: stored pre-freezing at room temperature for 96 hours / Study of umbilical cord blood cell subtypes and its viability prefreezing and post-thaw : stored pre-freezing at room temperature for 96 hoursPereira-Cunha, Fernanda Gonçalves, 1968- 24 August 2018 (has links)
Orientador: Irene Gyongyver Heidemarie Lorand Metze, Ângela Cristina Malheiros Luzo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T20:21:23Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: O sangue de cordão umbilical (SCU) é uma fonte de células-tronco para terapia celular e transplante de medula óssea. Devido a grande extensão territorial do Brasil, muitas vezes acontecem problemas logísticos na coleta de inúmeras unidades de SCU (USCU). Nosso objetivo foi estudar a mudança de proporções e a viabilidade dos diversos subtipos celulares do SCU, especialmente das células-tronco CD34+ até 96 horas após a coleta de amostras mantidas à temperatura ambiente (T.A.). Avaliamos ainda a modificação destes dados após o descongelamento das amostras. Cada subtipo celular foi identificado fenotipicamente usando citometria de fluxo. A viabilidade celular foi estudada utilizando o corante 7-aminoactinomicina (7-AAD). A funcionalidade das células-tronco CD34+ foi examinada através de ensaios clonogênicos. Num primeiro estudo foram analisadas trinta e seis USCU em 24, 48 e 96 horas após a coleta. As células-tronco CD34+ e os linfócitos T maduros aumentaram a porcentagem durante o período de estocagem. Os linfócitos B maduros e as células mesenquimais diminuiram, mantendo a viabilidade. Os granulócitos diminuíram a porcentagem com perda da viabilidade. Os monócitos e precursores B mantiveram-se estáveis. Os ensaios clonogênicos demonstraram diminuição no número de unidades formadoras de colônias (CFU) nas USCU estocadas até 96 horas (média 194/ 24 horas e 168/ 96 horas), mas todas as USCU apresentaram bom número de colônias. No segundo estudo foram analisadas vinte USCU em 24 e 96 horas após a coleta. Essas amostras foram congeladas e descongeladas após seis meses para serem reavaliadas. Os resultados das amostras pré-congelamento foram semelhantes aos encontrados no primeiro estudo. Os resultados pós-descongelamento demonstraram que as células CD34+ diminuíram, mas não significativamente, quando comparamos amostras estocadas 24 e 96 horas antes de processar. As células-tronco mesenquimais, precursores B, linfócitos B maduros e monócitos não apresentaram alterações estatísticas significantes. Os linfócitos T e granulócitos diminuíram significativamente. Houve crescimento de CFU em todas as amostras, embora o número de colônias tenha sido menor nas amostras estocadas 96 horas pré-congelamento quando comparadas às processadas após 24 horas (mediana 68 x 57; p <0.0001). No entanto, a maior diminuição foi observada pós-descongelamento (mediana 36 x 27 respectivamente). A diminuição do número de CFU estocadas 96 horas apresentou correlação com a porcentagem de células CD34+ inviáveis pré-congelamento. As células-tronco CD34+ e mesenquimais apresentaram boa viabilidade até 96 horas à T.A., mesmo pós-descongelamento. O processo de descongelamento diminuiu a porcentagem, mas não a viabilidade dessas células. O crescimento de CFU durante todo o período analisado comprovou a funcionalidade das células CD34+. A manutenção da viabilidade e funcionalidade das células-tronco do SCU estocados até 96 horas após a coleta à T.A., provendo número considerável de CFU mesmo após o congelamento e descongelamento poderá possibilitar a coleta de USCU de lugares mais distantes dos Bancos Públicos de SCU (BSCUP), o que seria muito importante para seu armazenamento. Portanto, as USCU poderiam ser manipuladas até 4 dias após a coleta quando necessário. Isto aumentaria consideravelmente o recrutamento de bolsas de SCU nos BSCUP, mantendo a segurança da fonte de células-tronco para uso na medicina regenerativa / Abstract: Umbilical cord blood (UCB) is a good source of stem cells for cell therapy and has been successfully used for bone marrow transplantation. In 2004, the Brazilian Public Network of Cord Blood Banks was founded. However, because our country is large, logistic problems could hamper the collection of numerous samples. Our aim was to evaluate the variation in proportion and viability of several UCB cell subsets, especially CD34+ stem-cells and their viability until 96 hours after collection of samples stored at room temperature. We evaluated also all cell subtypes and their viability and functionality kept frozen for 6 months and then thawed. Each cell subtype was identified by immunophenotyping and the viability was studied by 7-AAD incorporation and CD34+ stem-cell functionality was studied by clonogenic assay. In the first study we analysed thirty-six UCB units at 24, 48 and 96 hrs after collection and we demonstrated that CD34+ stem cells and mature T lymphocytes percentages increased during this period. Mature B lymphocytes and mesenchymal stem cells (MSCs) decreased, maintaining viability. Granulocytes decreased with loss of viability. Monocytes and immature B lymphocytes remained stable. Clonogenic assays showed a decrease in colony-forming unit (CFU) number in UCB units stored for 96 hours. But even so, an acceptable number CFU was maintained. In the second study we analysed twenty UCB units at 24 and 96 hrs after collection, frozen for 6 months and thawed for reevaluation. Pre freezing (PF) results were similar to those found in the first study. Post-thaw (PT) results showed that the number of CD34+ cells tended to decrease in kept 96 hrs at room temperature before processing. PT /24 and 96 hrs results of MSCs, immature and mature B cells and monocytes had no significant variation. T lymphocytes and granulocytes had a significant decrease. CFU growth was observed in all samples. Delay of 96 hrs PF was associated with a decrease in CFU number (median 68 x 57; p <0.0001). Moreover, a larger decrease was observed in PT samples (median 36 x 27 respectively). CFU loss at 96 hrs PF showed a correlation with the proportion of non-viable CD34+ before processing. CD34+ and MSCs stem-cells remained viable until 96 hrs after collection at room temperature even after freezing and thawing. CFU growth during all period analyzed confirming CD34+ functionality. The maintenance of viability and functionality of UCB stem cells stored until 96 hrs after collection at room temperature, providing a good number of colonies even after freezing and thawing could possibly allow the collection of UCBUs from places far away from UCB Banks, which would be of great value for increasing the number of Units in Umbilical Cord Blood Banks / Doutorado / Clinica Medica / Doutora em Clínica Médica
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Rôles des complexes isoformes de la PI3-K dans la survie et la résistance à l’anoïkose chez les cellules carcinomateuses colorectales humaines / Roles of PI3-K isoform complexes in cell survival and anoikis resistance in human colorectal cancer cellsBeauséjour, Marco January 2017 (has links)
La phosphatidylinositol-3 kinase (PI3-K) est un complexe comportant une sous-unité catalytique (C) et régulatrice (R). En ce qui concerne la classe I, cinq isoformes R (p85α, p55α, p50α, p85β et p55γ) et quatre isoformes C (p110α, p110β, p110δ et p110γ) sont connues. Plusieurs études ont souligné les rôles cruciaux de la voie PI3-K/Akt dans une panoplie de processus cellulaires, dont la survie. De plus, cette voie est l’une des plus altérées dans plusieurs types de cancers, dont le cancer colorectal (CCR). Par ailleurs, il est bien établi que l’acquisition d’une résistance à l’anoïkose constitue une étape cruciale et limitante dans la progression de plusieurs types de cancers, incluant une fois de plus le CCR. Nous avons précédemment démontré que les complexes isoformes PI3-K sont engagés/recrutés par la signalisation intégrines FAK/Src de suppression d’anoïkose et, conséquemment, exercent des rôles distincts dans la survie cellulaire des entérocytes normaux selon leur état de différenciation. Ainsi, l’hypothèse de recherche de la présente étude est que les complexes isoformes PI3-K contribuent sélectivement à l’acquisition d’une résistance à l’anoïkose, et ce, chez les cellules CCR humaines. Les objectifs principaux sont les suivants : 1) Établir le profil des complexes isoformes PI3-K chez des lignées cancéreuses colorectales humaines exhibant différents degrés de résistance à l'anoïkose (modéré à fortement élevé); et 2) Déterminer fonctionnellement les contributions des complexes isoformes PI3-K identifiés dans le maintien de résistance à l'anoïkose. Nos résultats indiquent que : 1) il existe des distinctions entre les profils de complexes isoformes PI3-K prédominants chez des cellules CCR exhibant différents degrés de résistance à l’anoïkose; 2) Ces complexes PI3-K peuvent jouer ou non des rôles dans la survie cellulaire, et ce, peu importe le degré de résistance à l’anoïkose exhibé; 3) les distinctions de profils de complexes isoformes ne semblent pas corrélées avec la progression de résistance à l’anoïkose; 4) il y aurait un mécanisme anormal de compensation entre les isoformes par rapport aux complexes formés et fonctions spécifiques chez les cellules CCR; et 5) une implication de la voie MEK/Erk compliquerait d’autant plus l’investigation des rôles des complexes PI3-K chez les cellules exhibant un degré élevé de résistance à l’anoïkose. Somme toute, cela laisse entrevoir que la progression dans la résistance à l’anoïkose implique une complexité plus importante qu’anticipée, chez les cellules CCR. / Abstract : The Phosphatidylinositol-3 kinase (PI3-K) is a lipid kinase enzyme complex formed of a catalytic (C) and a regulatory (R) subunit. To date, class I PI3-K members include five R (p85α, p55α, p50α, p85β et p55γ) and four C (p110α, p110β, p110δ et p110γ). Many studies already highlighted the crucial roles of the PI3-K/Akt pathway in many, if not all, cell processes, including cell survival. Moreover, PI3-K/Akt constitutes one of the most altered pathways in cancer, including in colorectal cancer (CRC). Incidentally, it is well established that the acquisition of anoikis resistance constitutes a crucial and limiting step in the progression of many cancers, including once again, in CRC. We have already demonstrated that PI3-K isoform complexes are selectively engaged by the anoikis-suppressing integrins/FAK/Src signaling and that this translates in distinct roles in normal enterocytes survival, according to their state of differentiation. This establishes a basis for the working hypothesis of the present report which is that PI3-K isoform complexes distinctly contributes to the acquisition and maintenance of anoikis resistance in human CRC cells. The main goals were as follows: 1) To establish the expression profiles of PI3-K isoform complexes in human CRC cells displaying differing anoikis resistance degrees; and 2) To define the functional contributions of said PI3-K isoform complexes in the maintenance of anoikis resistance. Our results indicate that 1) the expression profiles of PI3-K isoform complexes are distinct between human CRC cells displaying differing anoikis resistance degrees; 2) these PI3-K isoform complexes can perform, or not, roles in cell survival regardless of the anoikis resistance degree displayed; 3) the observed distinctions of the expression profiles of PI3-K isoform complexes do not correlate with the progression of anoikis resistance; 4) there seems to be an abnormal compensation mechanism between the various PI3-K isoforms linked not only with the nature of the complexes that are formed, but to their specific functions as well; and 5) the MEK/Erk pathway seems implicated in a cross-talk signaling loop, the nature of which further complexifies the investigation of the roles of PI3-K isoform complexes in human CRC cells displaying differing anoikis resistance degrees. Taken together, these observations suggest a more complex network of interactions than previously thought in human CRC cells.
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Relevance physiopathologique des productions cytokiniques dans la Leucémie Lymphoïde Chronique / Cytokines Production Relevance in Chronic Lymphocytic Leukemia PhysiopathologyMhibik, Maissa 19 March 2018 (has links)
Les lymphocytes B régulent la réponse immunitaire par la sécrétion de facteurs proinflammatoires ou immunosuppresseurs. Dans la Leucémie Lymphoïde Chronique (LLC),une sous-population de lymphocytes B CD5⁺ présente des propriétés immunosuppressives qui l’apparente aux lymphocytes B régulateurs notamment par la production d’IL-10. La survie des cellules leucémiques est, elle, associée à la réponse antigénique et à la production de cytokines dont l’IL-6. L’objectif de ce travail a été de caractériser dans la pathologie les populations produisant les cytokines pro-survie ou immunorégulatrices et d’analyser la relevance fonctionnelle de leur sécrétion. Nous avons identifié des sous-populations de cellules B leucémiques exprimant trois facteurs immunorégulateurs l’IL-10, le TGFβ1 et pour la première fois le facteur de transcription FOXP3, La proportion augmentée de cellules exprimant l’IL10 est associée à une diminution des cellules exprimant l’IL6. De manière importante, ce travail a identifié une boucle autocrine de stimulation de l’activité métabolique des cellules par l’IL10. La cytokine en se fixant à son récepteur permet l’activation des facteurs STAT3 et induit l’expression à la fois de protéines anti- apoptotiques de la famille Bcl2 mais surtout sa propre expression. Un blocage de cette boucle au niveau du récepteur à l’IL10 suspend l’avantage de survie des cellules tumorales. L’IL-6 ne déclenche pas ces mécanismes de maintien des cellules de LLC. Ce travail montre qu’en plus de son rôle sur les cellules du microenvironnement tumoral, l’IL-10 participe au maintien autocrine de la sous-population immunorégulatrice dans la LLC. / B cells produce pro-inflammatory or immunosuppressive factors to modulate the immuneresponse. In Chronic lymphocytic leukemia (CLL), a subset of the tumor lymphocytes produces IL10 and share immunoregulatory functions with regulatory B cells. CLL cell ssurvival is driven by antigenic response and pro-survival cytokines such as IL6. This project aimed at deciphering the cytokines profile of CLL subsets and analyzing their functional relevance. We identified immunoregulatory subsets producing IL-10, TGFβ1 and for the firsttime FOXP3. In patients, the increased proportion of cells expressing IL10 was correlated with decrease in IL6⁺ cells. Importantly we described an autocrine survival loop driven by IL10 in these cells. IL10 triggering led to STAT3 activation, induction of active pro-survival factors altogether with IL10 self-induction. Interrupting this loop with a blocking ab against IL10R prevented survival of the cells. IL6 did not manage such mechanisms. In conclusion,this work demonstrates that IL10 is an important mediator in CLL; the cytokine alters immune recognition of the tumor cells and sustains leukemic cells survival via the autocrine loop.
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MicroRNA Regulation of Autophagy during Programmed Cell Death: A DissertationNelson, Charles J. 03 March 2015 (has links)
Autophagy delivers cytoplasmic material to the lysosome for degradation, and has been implicated in many cellular processes, including stress, infection, survival, and death. Although the regulation and role that autophagy plays in stress, infection, and survival is apparent, its involvement during cell death remains relatively unclear. In this thesis I summarize what is known about the roles autophagy can play in cell death, and the differences between the utilization of autophagy during nutrient deprivation and cell death. Utilizing Drosophila melanogaster as a model system, the roles autophagy plays in both of these contexts can be studied. The goal of this thesis is to provide a better understanding of the regulatory mechanisms that distinguish between autophagy as a survival mechanism and autophagy as a cell death mechanism. From my studies I was able to determine that microRNAs can regulate autophagy in vivo, and that the microRNA miR-14 controls autophagy specifically during the destruction of the larval salivary glands of Drosophila melanogaster. I found that miR-14 regulates autophagy through modulation of IP3 and calcium signaling, and this miR-14 control of IP3 and calcium signaling does not influence the induction of autophagy during nutrient deprivation. Therefore, this knowledge demonstrates how autophagy can be regulated to distinguish its use during cell survival and death providing insight into how autophagy can used to treat diseases.
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Regulation of tumor growth and progression by Focal Adhesion Kinase (FAK) in a murine model of basal-like Breast CancerPaul, Ritama 22 October 2020 (has links)
No description available.
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