Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-07-01T12:18:37Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Tese_AtividadeAnitiproliferativaAntineoplasica.pdf: 5441260 bytes, checksum: 14e10e679631c83ea061a6d32c8472ca (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-07-30T11:57:44Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Tese_AtividadeAnitiproliferativaAntineoplasica.pdf: 5441260 bytes, checksum: 14e10e679631c83ea061a6d32c8472ca (MD5) / Made available in DSpace on 2014-07-30T11:57:44Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Tese_AtividadeAnitiproliferativaAntineoplasica.pdf: 5441260 bytes, checksum: 14e10e679631c83ea061a6d32c8472ca (MD5) Previous issue date: 2013 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas / Dentre os tumores que acometem o sistema nervoso, o glioblastoma multiforme (GBM), destaca-se por seu alto grau de agressividade e baixo prognóstico, apresentando em média uma sobrevida de 15 meses a partir do diagnóstico. O presente estudo objetivou investigar a atividade antiproliferativa e antineoplásica de quatro flavonoides isolados da espécie Brosimum acutifolium (Huber), duas flavanas: 4’-hidroxi-7,8-(2”,2”-dimetilpirano) flavana (BAS-1) e 7,4’-dihidroxi-8,(3,3-dimetilalil)-flavana, (BAS-4); e duas chalconas: 4,2’-dihidroxi-3’,4’-(2”,2”-dimetilpirano)-chalcona (BAS-6) e 4,2’,4’-trihidroxi-3’-(3,3-dimetilalil)-chalcona (BAS-7), em glioblastoma C6 de rato in vitro. Nossos resultados mostraram boa atividade citotóxica para as flavanas (BAS-1, -4) e para a chalcona BAS-7, com IC50 menor que 100 μM em teste de viabilidade pelo MTT, já a chalcona BAS-6, não demonstrou atividade citotóxica nas concentrações testadas. Estes flavonoides mostram ser menos citotóxico para célula não neoplásica (glia), com grau de segurança maior para a BAS-4 e BAS-7, uma vez que apresentaram menor efeito citotóxico à célula não neoplásica e menores índices hemolíticos. A análise de migração celular mostrou que o tratamento com BAS-1, BAS-4 e BAS-7 em baixas concentrações foi efetivo em promover inibição da migração celular. Estes três flavonoides também foram muito promissores em inibir a formação e o crescimento de colônia, além de promover parada no ciclo celular, com substancial aumento na população SubG0 para o tratamento com BAS-1 e BAS-4 com 100 μM. As flavanas BAS-1 e BAS-4 também mostraram maior capacidade de promover a perda na integridade do potencial de membrana mitocondrial (ΔΨm) e aumento para marcação com anexina V, indicativo de que estas drogas promovem morte por apoptose. No entanto a análise por microscopia eletrônica demonstrou marcantemente no tratamento com a BAS-4 a presença de vacúolos autofágicos, sugestivo que o processo de morte neste tratamento ocorre tanto por apoptose quanto autofagia. Com base nestes resultados pode-se concluir que dos flavonoides testados a BAS-1, BAS-4 e BAS-7 possuem potencial como agente antineoplásico na terapia do GBM, sendo a BAS-4 a mais promissora de todas. / Among the tumors that affect the nervous system, glioblastoma multiforme (GBM) is notable by its high degree of aggressiveness and poor prognosis, with an average survival of 15 months from diagnosis. The present study aimed to investigate the antiproliferative and antineoplastic activity of four flavonoids isolated from species Brosimum acutifolium (Huber). two flavans: 4'-hydroxy-7,8-(2",2"-dimethylpyran)-flavan (BAS-1) and 7,4'-dihydroxy-8-(3,3-dimethylallyl)-flavan (BAS-4), and two chalcones: 4,2'-dihydroxy-3',4'-(2",2"-dimetilpirano)-chalcone (BAS-6) and 4,2',4'-trihydroxy-3'-(3,3-dimethylallyl)-chalcone (BAS-7), tested on rat C6 glioblastoma in vitro. Our results showed good cytotoxic activity for flavans (BAS-1, -4) and the chalcone BAS-7, with IC50 less than 100 μM in the MTT viability test, since the chalcone BAS-6, showed no cytotoxicity at the concentrations tested. These flavonoids showed less cytotoxity for non-neoplastic cell (glia), with higher degree of security for the BAS and BAS-4-7, once showed lower cytotoxic effect on non-neoplastic cell, and less hemolytic. Analysis of cell migration showed that treatment with BAS-1; -4 and -7 at low concentrations was effective in promoting the inhibition of cell migration. These three flavonoids were also very promising in inhibiting colony formation and growth, and promote cell cycle arrest with a substantial increase in population SubG0 for treatment with BAS-1 and -4 with 100 μM. The flavans BAS-1 and -4 also showed increased ability to promote losing in the integrity of the mitochondrial membrane potential (ΔΨm) and increased for staining with Annexin V, indicating that these drugs cause death by apoptosis. However the analysis by electron microscopy showed markedly the presence of autophagic vacuoles in the treatment with BAS-4 suggesting that the process of cell death occurs by apoptosis as well as autophagy. Based on these results it can be concluded that the flavonoids BAS-1, -4, and -7 have potential as an anticancer agent in the therapy of GBM and BAS-4 is the most promising of all.

Glioblastoma multiforme (GBM) is a grade IV astrocytoma and is the most aggressive malignant primary brain tumor in adults. Without treatment, patients are expected to survive an average of three months. Conversely, current treatment regimens only extend survival to 12-14 months. Characteristically, GBM tumors are highly proliferative, invasive and stop responding to treatments relatively fast due to therapy resistance. Interestingly, GBM also exhibits high metabolic activity but manages to maintain a low level of reactive oxygen species (ROS). These ROS neutralization capabilities are sustained by system Xc–, a sodium-independent, electro neutral transporter that is found in the plasma membrane of GBM cells. System Xc– is composed of a regulatory heavy subunit (4F2hc) linked to a 12 transmembrane domain catalytic light chain subunit (xCT) that mediates the uptake of L-cystine into the cell, and L-glutamate out of the cell, at a 1:1 ratio. Imported cystine is quickly reduced to L- cysteine, the rate limiting substrate in glutathione (GSH) synthesis. Glutathione is a major antioxidant in the central nervous system that is responsible for maintaining intracellular redox homeostasis by neutralizing ROS by direct and indirect methods. The function of chemo and radiation therapy is to generate significant levels of ROS that tigger the cell to undergo apoptosis. High intracellular GSH levels in cancer cells are associated with drug resistance and detoxification of alkylating agents such as temozolomide (TMZ). Therefore, system Xc– represents a potential target to reduce glioma cell survival and reduce tumor progression. Sulfasalazine is an FDA approved drug in the treatment of arthritis and Crohne’s disease and has been shown to inhibit system Xc–. In vitro SASP studies demonstrated a strong antitumor potential in preclinical mouse models of malignant glioma. However, two clinical trials using sulfasalazine with standard chemo and radiation therapy to treat GBM patients were terminated due to off-target effects. Both results showed high toxicity and no change in the overall survival of patients. These studies demonstrate the need for a more effective inhibitor of system Xc–. To further elucidate the role of system Xc– in GBM survival, stable xCT knock-down and over-expressing U251 glioma cells were generated. These lines were characterized for survival, proliferation, apoptosis and resistance to oxidative and genotoxic insult. As expected xCT-knockdown cells exhibited lower GSH levels, increased intracellular ROS and markers for apoptosis after oxidative and genotoxic insult. The xCT-over-expressing cells displayed higher levels of GSH, increased resistance to hydrogen peroxide and various chemotherapy drugs including TMZ. An interesting unforeseen result of xCT over-expression in glioma cells was an increase in the metabolic activity as a result of increased mitochondria. Using xCT-modified glioma lines stably, we demonstrate for the first time that system XC– over-expression not only promotes survival under oxidative stress but may also decreases sensitivity to chemotherapy treatment and increase metabolic properties. Therefore, therapeutic manipulation of this transporter either alone or in combination with other treatments may improve clinical outcome in patients diagnosed with GBM.

No description available.

Orientador: Maria Palmira Daflon Gremião / Banca: Marcelo Bispo de Jesus / Banca: Heloisa Sobreiro Selistre de Araujo / Banca: Beatriz Stringhetti Ferreira Cury / Banca: Maria Palmira Daflon Gremião / Resumo: Os glioblastomas multiformes (GBMs) são os tumores mais invasivos do sistema nervoso central (SNC) e sua invasividade está relacionada com a interação entre glicoproteínas da matriz extracelular com integrinas presentes nas células tumorais. As integrinas α5β1, αvβ5, e αvβ3 são fortemente expressas em GBMs, e podem ser utilizadas como moléculas alvo na terapia e no diagnóstico por imagem dos tumores do SNC. Os inibidores de integrinas cRGDfV, cRGDfK e vicrostatin têm sido estudadas no tratamento de GBMs pois inibem as integrinas αvβ3, αvβ5 e α5β1, e, assim, exibem potentes propriedades antitumorais. Entretanto, a aplicação de proteínas terapêuticas é limitada freqüentemente pela baixa estabilidade em fluídos fisiológicos e a baixa penetração através das membranas biológicas. Para contornar estes problemas, tem˗se buscado novos sistemas de liberação de fármacos e rotas alternativas de administração, como por exemplo, a via nasal. Assim, este trabalho teve como objetivo a encapsulação dos peptídeos cRGDfV e cRGDfK em nanopartículas de quitosana, pelo método de gelificação ionotrópica, empregando o planejamento fatorial 23. Este sistema baseado em quitosana promoveu um aumento da mucoadesão e podem auxiliar o acesso dos peptideos cRGDfV e cRGDfK ao SNC pela via nasal. Outra estratégia utilizada nesse trabalho foi a utilização das nanopartículas de quitosana escolhidas no planejamento fatorial para serem modificadas com PEG por meio de interações supramoleculares e também por int... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Glioblastoma multiforme (GBMs) is the most invasive tumor from central nervous system (CNS) and its invasiveness is related to interaction between glycoproteins of extracellular matrix and integrins present in tumor cells. Integrins α5β1, αvβ5, e αvβ3 are overexpressed in GBMs and they could be used as target molecules in the treatment and diagnostic imaging of the tumors from CNS. The disintegrins cRGDfV, cRGDfK and vicrostatin have been studied for the treatment of GBMs because they inhibit the integrins αvβ3, αvβ5, and α5β1, and, therefore, they show potent anti˗tumor properties. However, the administration of therapeutic proteins is limited by their low stability in physiological fluids and low penetration in biological membranes. To overcome these problems, drug delivery systems have been developed and alternative route of administration, such as nasal administration, has been used. Thus, the aim of this study was the development of chitosan nanoparticles, employing factorial design, by the means of ionotropic gelification and the encapsulation of disintegrins cRGDfV e cRGDfK. The chitosan˗based drug delivery system increased the mucoadhesion, which could promote the blood˗brain barrier permeation of disintegrins cRGDfV and cRGDfK. Another strategy aimed in this work was the use of chitosan nanoparticles selected by factorial design to be modified with PEG by supramolecular interactions and also by covalent interactions with methoxy˗polyethylene glycol and maleimide˗polyethylene glycol˗hydroxisuccinimide. The modified nanoparticles by covalent interactions were functionalized through linkage of disintegrin cRGDfK on nanoparticles' surface in order to improve the targeting of nanoparticles to tumor environment by specific interactions with the integrins overexpressed in... (Complete abstract click electronic access below) / Doutor

Le glioblastome est la plus fréquente et la plus agressive des tumeurs cérébrales primaires.<p>Malgré un traitement standard pluridisciplinaire (chirurgie, radiothérapie et chimiothérapie),<p>la médiane de survie des patients atteints de ce type de tumeur est de 15 mois et aucun patient<p>n’a pu être guéri à ce jour. Ce pronostic très sombre est directement lié à la capacité<p>d’invasion diffuse du parenchyme cérébral par les cellules gliales tumorales, ce qui rend<p>impossible une résection chirurgicale totale. De plus, ces cellules sont particulièrement<p>résistantes aux traitements chimiothérapeutiques de type pro-apoptotique, entrainant une<p>récidive quasi inévitable de la tumeur. De nombreuses stratégies thérapeutiques telles que<p>l’immunothérapie ou les thérapies ciblées sont actuellement explorées pour tenter de<p>combattre ces tumeurs. Cependant, leur efficacité au niveau clinique s’est avérée décevante. Il<p>devient donc indispensable d’identifier de nouveaux agents thérapeutiques afin d’améliorer la<p>survie des patients atteints de glioblastome.<p>Dans ce travail, nous avons caractérisé les propriétés anticancéreuses in vitro et in vivo de<p>deux terpénoïdes extraits de champignons, la fusicoccine A et l’ophioboline A, puis nous<p>avons caractérisé en partie leur mécanisme d’action anti-tumoral dans des cellules de<p>glioblastome.<p>Tout d’abord, nous avons montré que l’activité inhibitrice de croissance in vitro de la<p>fusicoccine A et de l’ophioboline A n’était pas dépendante du degré de sensibilité ou de<p>résistance à l’apoptose des cellules gliales tumorales. Nous avons ensuite mis en évidence que<p>la fusicoccine A était capable de diminuer l’invasion des cellules de glioblastome in vitro en<p>ciblant la kinase focale d’adhérence (FAK). Dans le même temps, nous avons démontré que<p>l’ophioboline A était capable d’induire la mort de ces cellules par paraptose en inhibant<p>l’activité du canal ionique BKCa. Ces deux cibles sont intéressantes car en plus d’être<p>surexprimées dans les glioblastomes, elles interviennent dans de nombreux processus<p>cellulaires tels que la prolifération, la migration et la survie cellulaire.<p>Pour finir, nous avons analysé le pouvoir anti-tumoral in vivo de ces deux terpénoïdes en<p>utilisant un modèle murin de mélanome métastatique, couramment utilisé dans notre<p>laboratoire. Seule l’ophioboline A, injectée en intrapéritonéal à 10 mg/kg, augmentait de<p>manière significative la survie des souris traitées avec cette molécule par rapport aux souris<p>contrôles. Dans ce premier modèle, nous n’avions pas déterminé les conditions optimales<p>9<p>pour l’évaluation in vivo de la fusicoccine A et de l’ophioboline A. Lorsque celles-ci seront<p>définies, des modèles de xénogreffes orthotopiques de glioblastomes humains implantées dans<p>le cerveau de souris immunodéficientes seront utilisés.<p>En conclusion, l’ophioboline A, pouvant être produite en quantités industrielles par culture<p>du champignon qui la synthétise, possédant un mécanisme d’action original et montrant déjà<p>un début d’activité in vivo, pourrait représenter une molécule méritant des études plus<p>approfondies en termes d’agent thérapeutique susceptible de combattre les glioblastomes. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

No description available.

Das Glioblastoma multiforme gehört zu den ZNS-Tumoren neuroepithelialen Ursprungs. Es zeichnet sich durch ein multiformes Zellbild, einen geringen Differenzierungsgrad und eine schnelle Krankheitsprogression aus. Trotz mikrochirurgischer Entfernung und anschließender Radiochemotherapie entwickeln die Patienten im Durchschnitt nach 7 Monaten einen Rezidivtumor und haben eine mittlere Überlebenszeit von 14,6 Monaten. Die Rezidivneigung stellt somit ein großes Problem in der Behandlung von Glioblastompatienten dar. In früheren Arbeiten konnte nachgewiesen werden, dass die Rezidivtumore eine andere Zellzusammensetzung und auch ein aggressiveres Wachstumsverhalten als deren Primärformen aufweisen. Ziel dieser Arbeit war es, zu prüfen ob mittels 2D-Gelelektrophorese und anschließender MALDI-TOF-Massenspektrometrie Unterschiede im Proteinexpressionsmuster zwischen Gewebeproben vom Primärtumor eines Glioblastoms WHO Grad IV und dem korrespondierendem Rezidivtumor eines Patienten detektierbar sind. Hierbei wurden 43 Proteine als differentiell exprimiert erkannt, von denen mit Hilfe der MALDI-TOF-Massenspektrometrie sechs genauer charakterisiert wurden. Vier der sechs Proteine waren im Rezidivtumor erhöht: EnoylCoA-Hydratase, ATP-Synthase Untereinheit d, Tropomyosin alpha-3-Kette Isoform 2 und Cathepsin D. Die anderen zwei waren im Rezidivtumor niedriger ausgeprägt: Nukleosid-Diphosphatkinase A und L-3-Phosphoserin-Phosphatase. Eine weitere Untersuchung mittels Western-Blot-Analyse bestätigte, dass Cathepsin D (als eines der sechs charakterisierten Proteine) tatsächlich auch in den Rezidivtumoren dreier weiterer Patienten stärker exprimiert war als in den korrespondierenden primären Glioblastomen.

Glioblastoma multiforme (GBM) ist der nach WHO am gefährlichsten eingestufte Hirntumor astrozytären Ursprungs. Patienten versterben ohne Behandlung etwa drei bis sechs Monaten nach Diagnose, die derzeitig modernste Behandlung mit Chemo-Radiotherapie verlängert das mediane Überleben auf 12-15 Monate. Trotz intensiver Forschung gibt es zurzeit keine realistische Heilungschance. Bislang erfolgt der Großteil der Forschung an Zellkulturen oder mit Hilfe von Tiermodellen, bei denen ein Tumor künstlich erzeugt wird. Dabei ergeben sich Probleme für die Übertragung der Ergebnisse auf den Menschen. Zellkulturen werden z.B. als sogenannte Monolayer-Kulturen gehalten, was bedeutet, dass ihnen der natürliche Gewebeverband und die für Signalling-Wege wichtige extrazelluläre Matrix fehlen. Außerdem werden solche Langzeitkulturen häufig subkultiviert und mutieren dadurch in Richtung einer klonalen Linie, was zwar Ergebnisse leichter reproduzierbar macht, aber nicht die Situation im Patienten widerspiegelt. Tierversuche implizieren zwar den Gewebeverband im Körper, jedoch müssen die dafür verwendeten Nager immunsupprimiert sein, so dass sie den induzierten Tumor nicht abstoßen. Dies erzeugt wiederum ein künstliches Umfeld. In diesem Projekt wird untersucht, ob sich humane GBM-Gewebe als sogenannte Slice-Kultur halten lassen und als Testsysteme zur Untersuchung der Wirkung von Chemotherapeutika sowie Bestrahlung geeignet sind. Bei dieser Kultivierungsmethode wird das Gewebe in Scheiben (Slices) geschnitten, wobei alle Zellen im Verband sowie die 3D-Struktur erhalten bleiben. Wegen des humanen Ursprungs entfällt das Problem des Speziesunterschiedes. Das Gewebe wird direkt aus dem Operationssaal ins Labor transferiert und weiterverarbeitet. Wir konnten bislang zeigen, dass Slice-Kulturen von humanem GBM über mindestens zwei Wochen in Kultur vital bleiben und ihre ursprüngliche charakteristische Morphologie beibehalten. Etablierte Behandlungsmethoden wie die Gabe von Temozolomid oder Röntgenbestrahlung zeigen auch in kultivierten Slices bekannte Effekte wie Induktion von DNA-Doppelstrangbrüchen, Reduktion von Proliferation und Aktivierung des Apoptose-Enzyms Caspase 3. Eine neue Therapieoption besteht seit einigen Jahren in der Bestrahlung mit Kohlenstoffionen (12C), die an der GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt entwickelt und getestet wurde. Derzeit wird diese Therapie sehr erfolgreich an soliden Tumoren im Kopf- und Halsbereich angewendet und soll nun auf weitere Tumorarten ausgedehnt werden. Eine Kooperation mit der dortigen Biophysik-Gruppe wurde initiiert, um humane GBM-Slices mit 12C zu bestrahlen. Bislang wurde das entsprechende Setup etabliert und erste Experimente durchgeführt. Die ersten Ergebnisse wurden kürzlich publiziert. Weiterhin soll nun geprüft werden, ob das Ansprechen der GBM Slice-Kulturen mit dem Überleben der Patienten korreliert bzw. ob resistente Kulturen aus Patienten stammten, die schlecht auf die Therapie reagierten. Außerdem sollen überlebende Zellen in den Slices nach Behandlung auf ihre molekularen Eigenschaften geprüft werden, um Hinweise auf die Mechanismen der Tumorresistenz zu erhalten. Langfristig könnten diese Slice-Kulturen genutzt werden, um neuartige Wirkstoffe in der Vorklinik zu prüfen oder eine optimierte, personalisierte Therapie für Patienten zu ermitteln.

This thesis project serves to fill experimental gaps needed to advance the goal of performing pre-clinical trials using an orthotopic rat glioblastoma model to evaluate the efficacy of high-frequency electroporation (H-FIRE) and QUAD-CTX tumor receptor-targeted cytotoxic conjugate therapies, individually and in combination, in selectively and thoroughly treating glioblastoma multiforme. In order to achieve this, an appropriate model must be developed and characterized. I have transduced F98 rat glioma cells to express red-shifted firefly luciferase, which will facilitate longitudinal tumor monitoring in vivo through bioluminescent imaging. I have characterized their response to H-FIRE relative to DI TNC1 rat astrocytes. I have demonstrated the presence of the molecular targets of QUAD in F98 cells. The in vitro characterization of this model has enabled preclinical studies of this promising glioblastoma therapy in an immunocompetent rat model, an important step before advancing ultimately to clinical human trials. / Master of Science / Treating glioblastoma multiforme (GBM), a form of cancer found in the brain, has not been very successful; patients rarely live two years following diagnosis, and there have been no major breakthrough advances in treatment to improve this outlook for decades. We have been working on two treatments which we hope to combine. The first is high-frequency electroporation (H-FIRE), which uses electrical pulses to kill GBM cells while leaving healthy cells alive and blood vessels intact. The second is QUAD-CTX, which combines a toxin with two types of protein that attach to other proteins that are more common on the surface of GBM cells than healthy cells. We have shown these to be effective at disproportionately killing human GBM cells growing in a lab setting. Before H-FIRE and QUAD-CTX may be tested on humans, we need to show them to be effective in an animal model, specifically rats. I have chosen rat glioma cells that will behave similarly to human GBM and a rat species that will not have an immune response to them. I have made these cells bioluminescent so that we may monitor the tumors as they grow and respond to our treatments. I have also shown that QUAD-CTX kills these rat glioma cells, as does H-FIRE. Because of this work, we are ready to begin testing these two treatments in rats.

No description available.