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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Novas modalidades terapêuticas para o carcinoma mucoepidermoide e seus efeitos na população de células tronco tumorais / Novel therapeutic modalities for mucoepidermoid carcinoma and its effects on the cancer stem cell population

Wagner, Vivian Petersen January 2016 (has links)
O carcinoma mucoepidermoide (CME) representa a neoplasia maligna de glândula salivar mais comum. Tumores com alto grau histológico e casos avançados, com metástase regional ou a distância, apresentam taxas de sobrevida extremamente baixas em decorrência da falta de terapias eficazes. A radioterapia é usualmente aplicada como terapia adjuvante ou primeira linha de tratamento de tumores inoperáveis, entretanto o perfil de resistência do CME à radioterapia permanece não elucidado. Outra abordagem em tumores avançados é a quimioterapia, usualmente a base de cisplatina, aplicada como tratamento meramente paliativo. Um dos principais pontos chave envolvidos na resistência tumoral às terapias convencionais é a manutenção de uma população celular com alto potencial tumorigênico, chamadas de células tronco tumorais (CTT). Estas células apresentam capacidade de evadir terapias convencionais e são responsáveis pelo aparecimento de metástases e recidivas. Evidências recentes sugerem que a utilização de terapias combinadas possuem maior potencial de reduzir a resistência tumoral. Desta forma, no primeiro estudo nosso objetivo foi identificar o perfil de resistência à radioterapia de linhagens celulares de CME, vias associadas com a radio-resistência adquirida e formas de sensibilizar farmacologicamente as células de CME, incluindo as CTT, à radiação ionizante. Os resultados demonstraram que as linhagens de CME apresentam diferentes perfis de resistência à radiação ionizante, sendo a linhagem mais resistente capaz de ativar intrinsicamente o NFκB frente a baixas doses de radiação. Além disso, a resistência das linhagens mais sensíveis foi estimulada quando a vida do NFκB foi excitada. A inibição farmacológica do NFκB com Emetine foi realizada com sucesso através da inibição do eixo IKK-β/IκBα/NFκB. A utilização de Emetine previamente a radiação ionizante foi capaz de aumentar a sensibilidade das células de CME assim como diminuir o percentual de CTT. No segundo estudo nosso objetivo foi identificar a resposta tumoral, incluindo das CTT, à terapia única ou combinada utilizando dois alvos terapêuticos distintos: NFκB (tratamento com Emetine) e acetilação de histonas (tratamento com SAHA). Os resultados mostraram que uma dose de Emetine é capaz de inibir a proliferação celular em todas as linhagens de CME analisadas, enquanto que o SAHA apresentou este efeito em apenas 50% das linhagens. Por outro lado, o SAHA foi mais eficaz em reduzir a população de CTT que o Emetine. A terapia combinada foi mais eficaz do que as terapias individuais em relação a proliferação celular e a depleção de CTT. Através da analise dos resultados dos dois estudos, podemos concluir que a resistência tumoral do CME é superada com maior êxito quando mais de uma forma de tratamento é empregada. A associação de Emetine com a irradiação ou de SAHA com Emetine se mostrou eficaz no controle do tumor através da erradicação da população de CTT. / Mucoepidermoid carcinoma (MEC) represents the most common salivary gland cancer. High-grade tumors and advanced cases, presenting regional or distant metastasis, exhibit extremely low survival rates due to a lack of effective therapies. Radiotherapy is frequently applied as adjuvant therapy or as first-line treatment in inoperable cases. Nevertheless, the resistance profile of MEC to radiotherapy remains unclear. Chemotherapy, most commonly cisplatin, used for advanced cases is considered merely palliative. A key point involved in tumor resistance to conventional therapies is the maintenance of a cell population with high tumorigenic potential, called cancer stem cells (CSC). These cells have the ability to evade conventional therapies and are responsible for metastases and recurrences. Recent evidences support that combined therapies are more effective in reducing tumor resistance. Therefore, in the first study our objective was to identify the resistance profile of MEC cell lines to ionizing radiation, pathways associated with acquired resistance and ways to sensitize pharmacologically MEC cells, including CSC, to ionizing radiation. The results demonstrated that MEC cell lines present different resistance profile to ionizing radiation and the most resistant cell line is capable to activate intrinsically NFκB after low doses of irradiation. Moreover, resistance of sensitive cell lines can be triggered by NFκB activation. Pharmacological inhibition of NFκB with Emetine was achieved through IKK-β/IκBα/NFκB axis inhibition. The use of Emetine prior to irradiation was efficient in increasing cell sensibility as well as decrease the percentage of CSC. In the second study, our aim was to identify the tumor response, including of CSC, to single or combined therapy using two distinc therapeutic targets: NFκB (treated with Emetine) and histone acetylation (treated with SAHA). The results demonstrated that a single dose of Emetine was capable to inhibit cell proliferation in all MEC cell lines, while SAHA achieved this result in only 50% of cell lines analyzed. On the other side, SAHA was more efficient than Emetine in disrupting CSC population. The combined therapy was more effective than both single agent therapies regarding cell proliferation and CSC depletion. By analysing both studies results, we can conclude that the tumor resistance of MEC is overcome with greater success when more than one form of treatment is employed. The association of Emetine with irradiation or SAHA with Emetine is effective in tumor control by eradicating the CSC population.
62

Novas modalidades terapêuticas para o carcinoma mucoepidermoide e seus efeitos na população de células tronco tumorais / Novel therapeutic modalities for mucoepidermoid carcinoma and its effects on the cancer stem cell population

Wagner, Vivian Petersen January 2016 (has links)
O carcinoma mucoepidermoide (CME) representa a neoplasia maligna de glândula salivar mais comum. Tumores com alto grau histológico e casos avançados, com metástase regional ou a distância, apresentam taxas de sobrevida extremamente baixas em decorrência da falta de terapias eficazes. A radioterapia é usualmente aplicada como terapia adjuvante ou primeira linha de tratamento de tumores inoperáveis, entretanto o perfil de resistência do CME à radioterapia permanece não elucidado. Outra abordagem em tumores avançados é a quimioterapia, usualmente a base de cisplatina, aplicada como tratamento meramente paliativo. Um dos principais pontos chave envolvidos na resistência tumoral às terapias convencionais é a manutenção de uma população celular com alto potencial tumorigênico, chamadas de células tronco tumorais (CTT). Estas células apresentam capacidade de evadir terapias convencionais e são responsáveis pelo aparecimento de metástases e recidivas. Evidências recentes sugerem que a utilização de terapias combinadas possuem maior potencial de reduzir a resistência tumoral. Desta forma, no primeiro estudo nosso objetivo foi identificar o perfil de resistência à radioterapia de linhagens celulares de CME, vias associadas com a radio-resistência adquirida e formas de sensibilizar farmacologicamente as células de CME, incluindo as CTT, à radiação ionizante. Os resultados demonstraram que as linhagens de CME apresentam diferentes perfis de resistência à radiação ionizante, sendo a linhagem mais resistente capaz de ativar intrinsicamente o NFκB frente a baixas doses de radiação. Além disso, a resistência das linhagens mais sensíveis foi estimulada quando a vida do NFκB foi excitada. A inibição farmacológica do NFκB com Emetine foi realizada com sucesso através da inibição do eixo IKK-β/IκBα/NFκB. A utilização de Emetine previamente a radiação ionizante foi capaz de aumentar a sensibilidade das células de CME assim como diminuir o percentual de CTT. No segundo estudo nosso objetivo foi identificar a resposta tumoral, incluindo das CTT, à terapia única ou combinada utilizando dois alvos terapêuticos distintos: NFκB (tratamento com Emetine) e acetilação de histonas (tratamento com SAHA). Os resultados mostraram que uma dose de Emetine é capaz de inibir a proliferação celular em todas as linhagens de CME analisadas, enquanto que o SAHA apresentou este efeito em apenas 50% das linhagens. Por outro lado, o SAHA foi mais eficaz em reduzir a população de CTT que o Emetine. A terapia combinada foi mais eficaz do que as terapias individuais em relação a proliferação celular e a depleção de CTT. Através da analise dos resultados dos dois estudos, podemos concluir que a resistência tumoral do CME é superada com maior êxito quando mais de uma forma de tratamento é empregada. A associação de Emetine com a irradiação ou de SAHA com Emetine se mostrou eficaz no controle do tumor através da erradicação da população de CTT. / Mucoepidermoid carcinoma (MEC) represents the most common salivary gland cancer. High-grade tumors and advanced cases, presenting regional or distant metastasis, exhibit extremely low survival rates due to a lack of effective therapies. Radiotherapy is frequently applied as adjuvant therapy or as first-line treatment in inoperable cases. Nevertheless, the resistance profile of MEC to radiotherapy remains unclear. Chemotherapy, most commonly cisplatin, used for advanced cases is considered merely palliative. A key point involved in tumor resistance to conventional therapies is the maintenance of a cell population with high tumorigenic potential, called cancer stem cells (CSC). These cells have the ability to evade conventional therapies and are responsible for metastases and recurrences. Recent evidences support that combined therapies are more effective in reducing tumor resistance. Therefore, in the first study our objective was to identify the resistance profile of MEC cell lines to ionizing radiation, pathways associated with acquired resistance and ways to sensitize pharmacologically MEC cells, including CSC, to ionizing radiation. The results demonstrated that MEC cell lines present different resistance profile to ionizing radiation and the most resistant cell line is capable to activate intrinsically NFκB after low doses of irradiation. Moreover, resistance of sensitive cell lines can be triggered by NFκB activation. Pharmacological inhibition of NFκB with Emetine was achieved through IKK-β/IκBα/NFκB axis inhibition. The use of Emetine prior to irradiation was efficient in increasing cell sensibility as well as decrease the percentage of CSC. In the second study, our aim was to identify the tumor response, including of CSC, to single or combined therapy using two distinc therapeutic targets: NFκB (treated with Emetine) and histone acetylation (treated with SAHA). The results demonstrated that a single dose of Emetine was capable to inhibit cell proliferation in all MEC cell lines, while SAHA achieved this result in only 50% of cell lines analyzed. On the other side, SAHA was more efficient than Emetine in disrupting CSC population. The combined therapy was more effective than both single agent therapies regarding cell proliferation and CSC depletion. By analysing both studies results, we can conclude that the tumor resistance of MEC is overcome with greater success when more than one form of treatment is employed. The association of Emetine with irradiation or SAHA with Emetine is effective in tumor control by eradicating the CSC population.
63

Caracterização dos efeitos antitumorais do guaraná sobre modelo murino de células tronco cancerosas / Characterization of the antitumor effects of guarana on murine model of cancer stem cells

Arina Lázaro Rochetti 16 December 2015 (has links)
O câncer de pulmão está entre os tipos de câncer com maiores índices de mortalidade no mundo. Na década de 90, houve a descoberta de populações de células tumorais com características de células-tronco e implicou na hipótese das células-tronco cancerosas (CTCs). Se a hipótese das CTCs for correta, a recorrência/recidiva dos cânceres é gerada por uma porcentagem de células (CTCs) que prolifera pouco e é resistente a quimioterapia convencional. Desta forma, a busca por novos alvos terapêuticos que tenham como alvo estas CTCs tem enorme implicação no desenvolvimento de novos fármacos ou modalidades terapêuticas contra o câncer. O guaraná (Paullinia cupana Mart var. sorbilis) tem demonstrado efeitos promissores sobre o câncer, em especial efeitos quimiopreventivos e antineoplásicos. Portanto, objetivando-se neste projeto avaliar a presença de CTCs a partir de células tumorais de pulmão de camundongo, onde se possa conseguir rapidamente uma alta porcentagem deste tipo celular para posteriores estudos, além de avaliar os efeitos do extrato etanólico do guaraná e de suas frações butanólica e aquosa, sobre as células tumorais e em especial verificar os efeitos sobre a população rica em CTCs, onde foi possível observar a presença de possíveis CTCs, a partir de cultivo de células tumorais de pulmão de camundongo, como também que o guaraná apresentou um efeito sobre estas possíveis CTCs devido a diminuição da expressão dos genes ABCG2 e ALDH1a1. / Lung cancer is among the cancers with the highest mortality rates in the world. In the 90\'s, there was the discovery of tumor cell populations with stem cell characteristics implied in the case of cancer stem cells (CSCs). If the hypothesis is correct CSCs of the recurrence / relapse of cancers is generated by a percentage of cells (CSCs) that growth low and are more resistant to conventional chemotherapy. Thus, the search for new therapeutic targets that target these CSCs has huge implications in developing new drugs or therapeutic approaches against cancer. Guarana (Paullinia cupana Mart var. Sorbilis) has shown promising effects on cancer, especially chemopreventive and anticancer effects. Therefore, the objective in this project is to evaluate the presence of CSCs from tumor cells of mouse lung, where it can quickly get a high percentage of this cell type for further studies and to evaluate the effects of ethanol extract of guarana and its butanol and aqueous fractions on tumor cells and in particular to verify the effect on the population rich in CSCs, where it was possible to observe the possible presence of CSCs from cultivation of tumor cells from mouse lung, as well as guarana presented an effect on these CSCs possible to decreased expression of ABCG2 and ALDH1a1 genes.
64

Étude de l'impact de l'activité traductionnelle sur le phénotype tumoral dans le cancer du côlon / Impact of translational activity on colon cancer cell phenotype

Yazdani, Laura 22 September 2017 (has links)
Avec près d’un million de nouveaux cas par an à travers le monde, le cancer colorectal est un problème de santé publique majeur. Il est la 2ème cause de mortalité par cancer en France, ce fort taux de mortalité étant relié à un pourcentage important de récidives et de métastases. L’hétérogénéité tumorale, la dissémination, la résistance aux traitements et la récidive seraient notamment dues à une population particulière de cellules tumorales appelées cellules souches cancéreuses (CSC). Ces cellules sont dotées d’une capacité d’adaptation extraordinaire et la compréhension des mécanismes moléculaires sous-tendant cette plasticité cellulaire est un objectif majeur pour concevoir de nouvelles stratégies thérapeutiques les ciblant spécifiquement. La synthèse protéique joue un rôle clé dans la carcinogénèse : d’une part, une synthèse protéique élevée est nécessaire à la prolifération des cellules tumorales, d’autre part, la traduction sélective favorise l’expression de protéines pro-oncogéniques. Considéré pendant des années comme un acteur passif de la traduction, le ribosome semblerait jouer un rôle majeur dans la régulation de la synthèse protéique. En effet, des études récentes ont montré que la composition du ribosome était « flexible » et permettrait de favoriser la traduction de certains ARN messager (ARNm). De plus, l’expression de certaines protéines ribosomiques (PR) varie entre le tissu sain et le tissu cancéreux, parfois même entre la tumeur initiale et la métastase. Ce projet vise à déterminer de quelle manière le contrôle traductionnel intervient dans plusieurs étapes clé du cancer colorectal, en se focalisant tout particulièrement sur l’acquisition ou la perte de propriétés propres aux CSC. Cette étude permettra de mieux comprendre les mécanismes moléculaires exploités par les CSC afin de résister aux traitements et s’adapter à leur environnement. De plus, ce projet pourrait mettre en évidence un rôle exercé par certaines protéines ribosomiques dans le contrôle traductionnel, à travers la filtration des ARNm par le ribosome. A plus long terme, il pourrait déboucher sur le développement de nouveaux traitements permettant de cibler spécifiquement la machinerie traductionnelle des CSC. / Despite significant advances in diagnostics and treatment, colorectal cancer (CRC) remains a major cause of mortality worldwide and occurrence of metastasis represents the primary cause of death. Metastasis process, chemoresistance and tumor recurrence is powered by a minor subpopulation of tumor cells endowed with self‐renewal and multi‐lineage differentiation ability: the cancer stem cells (CSC).Translation of mRNA into protein is the final step in gene-expression process, which mediates the formation of the translatome from genomic information. Several mechanisms, such as signaling pathways, translation factors availability, alternative open reading frame and alternative initiation pathways account for real time translatome remodeling. Moreover, an emerging concept suggests that ribosome is heterogeneous and can be "reprogrammed". These "specialized ribosomes" would preferentially engage certain mRNA at the expense of others and therefore drive cell phenotype and favor cell adaptation. Many studies have correlated deregulation of both translation machinery composition and activity with cancer initiation and evolution. From that perspective, CSC might well represent a perfect model to test whether the translation apparatus takes an active part in tumor initiation, progression, and metastasis. Our goal is to demonstrate that protein synthesis is differentially regulated depending on cancer cell subpopulation and determine whether ribosomal heterogeneity could influence tumoral evolution and plasticity. In a long run, we envision the development of novel therapies based on specific targeting of translational control in CSC.
65

Withanolide D Exhibits Similar Cytostatic Effect in Drug-Resistant and Drug-Sensitive Multiple Myeloma Cells

Issa, Mark E., Wijeratne, E. M. K., Gunatilaka, A. A. L., Cuendet, Muriel 08 September 2017 (has links)
In spite of recent therapeutic advances, multiple myeloma (MM) remains a malignancy with very low curability. This has been partly attributed to the existence of a drug-resistant subpopulation known as cancer stem cells (CSCs). MM-CSCs are equipped with the necessary tools that render them highly resistant to virtually all conventional therapies. In this study, the growth inhibitory effects of withanolide D (WND), a steroidal lactone isolated from Withania somnifera, on drug-sensitive tumoral plasma cells and drug-resistant MM cells have been investigated. In MTT/XTT assays, WND exhibited similar cytostatic effects between drug-resistant and drug-sensitive cell lines in the nM range. WND also induced cell death and apoptosis in MM-CSCs and RPMI 8226 cells, as examined by the calcein/ethidium homodimer and annexin V/propidium iodide stainings, respectively. To determine whether P-glycoprotein (P-gp) efflux affected the cytostatic activity of WND, P-gp was inhibited with verapamil and results indicated that the WND cytostatic effect in MM-CSCs was independent of P-gp efflux. Furthermore, WND did not increase the accumulation of the fluorescent P-gp substrate rhodamine 123 in MM-CSCs, suggesting that WND may not inhibit P-gp at the tested relevant doses. Therefore, the WND-induced cytostatic effect may be independent of P-gp efflux. These findings warrant further investigation of WND in MM-CSC animal models.
66

Targeted therapy sensitivity and resistance in solid malignancies

Jokinen, E. (Elina) 28 October 2014 (has links)
Abstract Cancer is a major global killer and a challenge for the healthcare worldwide. Earlier cancer has been treated with surgery, radiation, chemotherapy and hormonal therapy. Unfortunately the efficiency of these therapies has shown to be limited and this has raised an enthusiasm for development of new, targeted cancer therapies that are based on activated oncogenes. The challenge of the targeted therapies is therapy resistance, de novo, adaptive and acquired. This work investigated targeted therapy sensitivity and resistance in lung cancer, breast cancer, colorectal cancer, and melanoma cell lines. The results of this study indicate that in some non-small cell lung cancer cell lines, dual PI3K and MEK inhibition is a more efficacious treatment than inhibition of either solely. It was also showed that the maximal effect of the dual inhibition can be achieved with alternative dosing schedules that are potentially more tolerable in clinical use. Furthermore, by combining ABT-263, entinostat or dasatinib to the dual PI3K and MEK inhibition, the efficiency of the therapy can be increased. Bcl-xl downregulation is a major determinant of the apoptotic response to the triple inhibitor treatment. The current work showed that cancer stem cells can mediate resistance to targeted therapies. Since these cells follow the stochastic model, concurrent therapy with a targeted agent and a stem cell targeting drug might be needed for maximal therapeutic efficiency. This study also showed that Gö6976 acts as a potent inhibitor of mutant EGFR despite the presence of T790M, the most important mechanism of acquired resistance for EGFR tyrosine kinase inhibitors in lung cancer, both in vitro and in vivo. / Tiivistelmä Syöpä on yksi johtavia kuolemanaiheuttajia ja tauti on maailmanlaajuinen haaste terveydenhuollolle. Perinteiset syöpähoidot käsittävät kirurgian, sädehoidon, kemoterapian ja hormonaalisen hoidon, mutta näiden rinnalle on noussut uusia, aktivoituneiden onkogeenien signaalien estoon perustuvia hoitoja. Tämä työ tutki kohdennettuja syöpähoitoja ja näihin hoitoihin liittyvää resistenssiä keuhko-, rinta- ja paksusuolen syövän sekä melanooman solulinjoissa. Tulokset osoittavat, että joissakin ei-pienisoluisen keuhkosyövän solulinjoissa yhdistetty PI3K- ja MEK-esto aiheuttaa tehokkaamman vasteen kuin kummankaan signaalireitin esto yksistään. Tässä työssä näytettiin myös, että maksimaalinen vaste yhdistetylle PI3K- ja MEK-estolle voidaan saavuttaa vaihtoehtoisilla annostelutavoilla, jotka ovat voisivat olla paremmin siedettyjä kliinisessä käytössä kuin kahden lääkkeen jatkuva annostelu. Tämä tutkimus osoitti lisäksi, että kaksoiseston tehokkuutta voidaan lisätä yhdistämällä hoitoon kolmas lääkeaine, ABT-263, entinostaatti tai dasatinibi. Bcl-xl proteiinilla on keskeinen rooli apoptoottisen vasteen määrittäjänä näille kolmen lääkkeen käsittelyille. Tämä työ osoitti, että syövän kantasolut voivat välittää resistenssiä kohdennetuille syöpähoidoille. Nämä solut noudattavat niin kutsuttua stokastista mallia, joten parhaan vasteen saaminen saattaa edellyttää että hoito kohdentuu sekä erilaistuneisiin että kantasolutyyppisiin syöpäsoluihin. Tässä tutkimuksessa osoitettin lisäksi, että Gö6976 toimii mutatoituneen EGFR:n estäjänä, huolimatta kehittyvää keuhkosyövissä resistenssiä välittävästä T90M mutaatiosta, sekä in vitro -että in vivo -malleissa.
67

Cancer stem cells and tumour associated macrophages in Glioblastoma Multiforme

Yu, Kenny January 2016 (has links)
Glioblastoma Multiforme (GBM) is a primary malignant brain cancer, affecting children and adults and has a very poor prognosis. Up to 30% of the tumour mass consists of host derived immune cells, and a better understanding of how these cells affect tumour behaviour is required. These cells, called ‘Tumour Associated Macrophages’ (TAM) have been shown to occur in peripheral solid organ cancers, where they can cause local immune suppression, increase invasiveness and aid tumour growth. In the brain however, TAMs can consist of centrally derived microglia and peripherally derived macrophages, and although these cells could be exerting different effects on the tumour, there is currently no reliable way of distinguishing between the two. Cancer Stem Cells (CSC) are a subpopulation of cells within the tumour mass with stem-like features, are capable of self-renewal, and can recapitulate a tumour in an immunocompromised mouse host. It is thought that these cells play a role in disease recurrence and hence represent a potential target for anti-GBM therapies. In the first project we investigate the interaction between Cancer Stem Cells and TAMs. We first describe a method of culturing CSCs and TAMs from a single human patient sample, followed by an investigation into the functional properties of these cell types. We found functional differences between established cell line pairings of U87-MG and CHME3 versus primary patient derived CSCs and TAM cell line pairings. Polarisation of microglia/TAMs with lipopolysaccharide caused significant decrease in proliferative capacity of the GBM cell lines. Next we used a Non-Myeloablative Conditioning System (NMCS) to selectively replace the peripheral bone marrow compartment of wild type animals with labelled bone marrow cells, without disturbing brain homeostasis. We demonstrate that peripheral cells home exclusively to the orthotopically implanted tumour, and that some of these cells are CD11b+ and Gr1+, suggestive of myeloid derived suppressor cells (MDSC). We evaluate current CD45 based gating strategies for distinguishing peripheral and central cells and show them to be inadequate. Finally we compared the chemosensitivity profiles of different patient derived CSC lines using high throughput content screening (HTCS), against currently approved chemotherapeutic drugs and rank these drugs in a response space, based on HTCS parameters including 2D and 3D culture with and without irradiation. Differential chemosensitivities were noted between different patient derived cell lines. Drugs not currently used in the treatment of GBM such as Actinomycin D and Mitoxantrone were also identified using HTCS, suggesting the potential utility of such an approach to personalised treatments in GBM.
68

Investigation of the anticancer activity and molecular mechanisms of Disulfiram in Glioblastoma Multiforme

Kannappan, Vinodh January 2015 (has links)
Glioblastoma Multiforme (GBM) is the most common lethal brain tumour associated with dismal survival rate. GBM is considered to be an incurable malignancy as these tumours evade all intricate attempts of therapy and no contemporary chemotherapeutic regimen is effective. Although the existence of cancer stem cells (CSCs) is still debatable, it is widely accepted that GBM has a small population of cells expressing CSC markers (~1%) that are highly resistant to chemo-radiation therapy. Recent evidence indicates that hypoxia induces cancer stem cell (CSC) phenotypes via epithelial-to-mesenchymal transition (EMT) that promote therapeutic resistance in solid tumours. Given that GBMs are extensively hypooxygenated heterogenous tumours, understanding the molecular relationship between hypoxia, biology of CSCs, EMT and chemoresistance would be invaluable for development of drugs that can target CSCs. Evidence suggests that hypoxia inducible factors (HIFs), NF-B and aldehyde dehydrogenase (ALDH) together orchestrate the stemness and chemoresistance in hypoxia induced CSCs. But the insights on the mechanisms still remain obscure. In this study we used an in vitro GBM CSC and hypoxia model along with NF-B-p65 and HIF transfected GBM cell lines to investigate the relationship between HIFs, NF-B activation and ALDH activity and their role in chemoresistance. The findings of this study demonstrated that GBM cells grown as spheres consist of a vast proportion of hypoxic cells with elevated CSC and EMT markers suggesting hypoxia induced EMT. GBM-CSCs are chemoresistant and displayed increased levels of HIFs, NF-B and ALDH activity. It was also observed that stable transfection of GBM cells with NF-B-p65 or HIFs induced CSC and EMT markers indicating their essential role in maintaining CSC phenotypes. The study also highlighted the importance of NF-B and ALDH in driving chemoresistance and the potential role of NF-B as the master regulator of hypoxia induced stemness in GBM cells. In this study, we used Disulfiram (DS), an anti-alcoholism drug, in combination with copper (Cu) to target the hypoxia-NF-B axis and inhibit ALDH activity to reverse chemoresistance in GBM CSCs. We showed that DS/Cu is cytotoxic to GBM cells and completely eradicated the resistant CSC population at low nanomolar levels in vitro. We also demonstrated that DS/Cu effectively inhibited GBM in vivo using newly formulated PLGA-DS nanoparticles. DS is an FDA approved drug with low/no toxicity to normal tissues and can freely pass through the blood brain barrier (BBB). Further study may lead to quick translation of DS into clinical trials.
69

Tumorspheres as an in vitro model for cancer stem-like cell characterization in non-small cell lung cancer. Prognostic implications

Herreros Pomares, Alejandro 17 February 2020 (has links)
[ES] El cáncer de pulmón es el tipo de cáncer más frecuentemente diagnosticado y la principal causa de muerte debida a cáncer en el mundo, con sólo un 15% de pacientes con una supervivencia mayor a 5 años tras el diagnóstico. La resección quirúrgica es el tratamiento estándar para los pacientes en estadios tempranos con un buen ECOG, pero el 75% de los pacientes son diagnosticados en estadios avanzados, cuando la intervención quirúrgica no es posible y entre un 35% y un 50% de los pacientes operados recaen tras una cirugía aparentemente exitosa. En los últimos años, se han logrado importantes avances en el desarrollo de la inmunoterapia y de tratamientos contra mutaciones conductoras, pero muchos pacientes todavía desarrollan resistencia, progresan y mueren. Esta resistencia terapéutica ha sido asociada a las células madre tumorales (CMTs), una población tumoral con propiedades de célula madre capaz de sobrevivir a las terapias convencionales y regenerar el tumor incluso cuando son indetectables. En esta tesis doctoral, se establecieron cultivos primarios de pacientes de cáncer de pulmón no microcítico (CPNM) resecados, usando ensayos de formación de tumoresferas para el enriquecimiento en CMTs y condiciones de adherencia para los controles. Las tumoresferas derivadas de pacientes mostraron capacidad de autorenovación y crecimiento exponencial ilimitado, alta resistencia a agentes quimioterápicos, capacidad de invasión y diferenciación in vitro y un elevado potencial tumorigénico in vivo. Usando PCR cuantitativa, se analizaron los perfiles de expresión de los cultivos y se determinó que NANOG, NOTCH3, CD44, CDKN1A, SNAI1 e ITGA6 eran los genes más diferencialmente expresados entre tumoresferas y células adherentes. Los análisis de inmunoblot e inmunofluorescencia confirmaron que las proteínas codificadas por estos genes se encuentran aumentadas en tumoresferas de los pacientes con adenocarcinoma y mostraron patrones de expresión y localización diferencial entre éstas y los controles en adherencia. El valor pronóstico de los genes significativamente sobreexpresados en tumoresferas fue evaluado in silico en una cohorte de 661 pacientes con CPNM procedente del TCGA. De todos ellos, CDKN1A, SNAI1 y ITGA6 mostraron estar relacionados con el pronóstico de los pacientes de acuerdo a un análisis de regresión de Cox y fueron seleccionados para construir una firma de expresión génica, denominada firma de CMTs. Los análisis de supervivencia por Kaplan-Meier mostraron que los pacientes con valores elevados de la firma tienen una supervivencia global (SG) menor para la cohorte completa de CPNM [37,7 vs. 60,40 meses, p = 0,001] y para la subcohorte de adenocarcinoma (ADC) [36,6 vs. 53,5 meses, p = 0,003], pero no para la de los epidermoides. Además, el análisis multivariante mostró que la firma de CMTs es un marcador pronóstico independiente para la SG de los pacientes en la cohorte completa [hazard ratio (HR): 1,498; intervalo de confianza (IC) 95%, 1,167-1,922; p = 0,001] y la subcohorte de ADC [HR: 1,869; IC 95%, 1,275-2,738; p = 0,001]. Esta firma fue también analizada en un grupo independiente de 245 pacientes procedentes del Consorci Hospital General Universitari de València, confirmando su valor pronóstico en los pacientes con ADC [42,90 vs. no alcanzado (NA) meses, p = 0,020]. En resumen, nuestros hallazgos aportan información pronóstica relevante para los pacientes con ADC de pulmón y establecen las bases para el desarrollo de nuevos tratamientos. / [CAT] El càncer de pulmó és el tipus de càncer més diagnosticat i la principal causa de mort deguda a càncer en el món, amb només un 15% de pacients amb una supervivència major a 5 anys després del diagnòstic. La resecció quirúrgica és el tractament estàndard per als pacients en estadis primaris amb un bon ECOG, però el 75% dels pacients són diagnosticats en estadis avançats, quan la intervenció quirúrgica no és possible i entre un 35% i un 50% dels pacients operats recauen després d'una cirurgia aparentment satisfactòria. En els últims anys, s'han aconseguit importants avanços en el desenvolupament de la immunoteràpia i de tractaments contra mutacions conductores, però molts pacients encara desenvolupen resistència, progressen i moren. Aquesta resistència a les teràpies ha estat relacionada amb les cèl·lules mare tumorals (CMTs), una població tumoral amb propietats de cèl·lula mare capaç de sobreviure a les teràpies convencionals i regenerar el tumor fins i tot quan són indetectables. En aquesta tesi doctoral, es van establir cultius primaris de pacients de càncer de pulmó no microcític (CPNM) ressecats, usant assajos de formació de tumoresferes per a l'enriquiment en CMTs i condicions d'adherència per als controls. Les tumoresferes derivades de pacients van mostrar capacitat d'autorenovació, creixement exponencial il·limitat, alta resistència a agents quimioteràpics, capacitat d'invasió i diferenciació in vitro i un elevat potencial tumorigènic in vivo. Usant PCR quantitativa, es van analitzar els perfils d'expressió dels cultius i es va determinar que NANOG, NOTCH3, CD44, CDKN1A, SNAI1 i ITGA6 eren els gens més diferencialment expressats entre tumoresferes i cèl·lules adherents. Les anàlisis de immunoblot i immunofluorescència van confirmar que les proteïnes codificades per aquests gens es troben augmentades en tumoresferes dels pacients amb adenocarcinoma i van mostrar patrons d'expressió i localització diferencial entre aquestes i els controls en adherència. El valor pronòstic dels gens significativament sobreexpressats en tumoresferes va ser avaluat in silico en una cohort de 661 pacients amb CPNM procedent del TCGA. De tots ells, CDKN1A, SNAI1 i ITGA6 van mostrar estar relacionats amb el pronòstic dels pacients d'acord a una anàlisi de regressió de Cox i van ser seleccionats per a construir una signatura d'expressió gènica, denominada signatura de CMTs. Les anàlisis de supervivència per Kaplan-Meier van mostrar que els pacients amb valors elevats de la signatura tenen una supervivència global (SG) menor per a la cohort completa de CPNM [37,7 vs. 60,40 mesos, p = 0,001] i per a la subcohort d'adenocarcinoma (ADC) [36,6 vs. 53,5 mesos, p = 0,003], però no per a la dels escamosos. A més, l'anàlisi multivariant va mostrar que la signatura de CMTs és un marcador pronòstic independent per a la SG dels pacients en la cohort completa [hazard ratio, (HR): 1,498; interval de confiança (IC) 95%, 1,167-1,922; p = 0,001] i la subcohort d'ADC [HR: 1,869; IC 95%, 1,275-2,738; p = 0,001]. Aquesta signatura va ser també analitzada en un grup independent de 245 pacients procedents del Consorci Hospital General Universitari de València, confirmant el seu valor pronòstic en els pacients amb ADC [42,90 vs. no arribat (NA) mesos, p = 0,020]. En resum, els nostres resultats aporten informació pronòstica rellevant per als pacients amb ADC de pulmó i estableixen les bases per al desenvolupament de nous tractaments. / [EN] Lung cancer is the most commonly diagnosed type of cancer and the leading cause of cancer-related death worldwide, with approximately 15% of patients surviving 5 years after diagnosis. Curative surgery is the standard of care for early-stage patients with a good performance status, but 75% are diagnosed at advances stages, when surgery is not possible, and 35-50% of the resected patients relapse after an apparently successful surgical treatment. Significant advances in the development of therapies against driver mutations and immune-based treatments for these patients have been achieved in recent years, but many patients still develop treatment resistance, progress, and die. The high resistance against these therapies has been associated to cancer stem-like cells (CSCs), a population with stem properties which is able to survive after conventional treatments and regenerate tumor even when are undetectable. In this thesis, primary cultures from early-stage non-small cell lung cancer (NSCLC) patients were established, using sphere-forming assays for CSCs enrichment and adherent conditions for the control counterparts. Patient-derived tumorspheres showed self-renewal and unlimited exponential growth potentials, resistance against chemotherapeutic agents, invasion and differentiation capacities in vitro, and superior tumorigenic potential in vivo. Using RTqPCR, gene expression profiles were analyzed, and NANOG, NOTCH3, CD44, CDKN1A, SNAI1, and ITGA6 were selected as the best contributors to distinguish tumorspheres from adherent cells. Immunoblot and immunofluorescence analyses confirmed that proteins encoded by these genes were consistently increased in tumorspheres from adenocarcinoma patients and showed differential localization and expression patterns. The prognostic role of genes significantly overexpressed in tumorspheres was evaluated in silico in a cohort of 661 NSCLC patients from TCGA. Based on a Cox regression analysis, CDKN1A, SNAI1 and ITGA6 were found to be associated with prognosis and used to calculate a gene expression score, named CSCs score. Kaplan-Meier survival analysis showed that patients with high CSCs score have shorter overall survival (OS) in the entire cohort [37.7 vs. 60.4 months, p = 0.001] and in the adenocarcinoma (ADC) subcohort [36.6 vs. 53.5 months, p = 0.003], but not in the squamous cell carcinoma one. Multivariate analysis indicated that this gene expression score is an independent biomarker of prognosis for OS in both, the entire cohort [hazard ratio (HR): 1.498; 95% confidence interval (CI), 1.167-1.922; p = 0.001], and the ADC subcohort [HR: 1.869; 95% CI, 1.275-2.738; p = 0.001]. This score was also analyzed in an independent group of 245 patients from Consorci Hospital General Universitari de València, confirming its prognostic value in the ADC subtype [42.90 vs. not reached (NR) months, p = 0.020]. In conclusion, our findings provide relevant prognostic information for lung ADC patients and the basis for developing novel therapies. / Herreros Pomares, A. (2020). Tumorspheres as an in vitro model for cancer stem-like cell characterization in non-small cell lung cancer. Prognostic implications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/137036 / TESIS
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Induction of Cancer Stem Cell Properties in Colon Cancer Cells by Defined Factors / 特定因子による大腸癌細胞への癌幹細胞特性の誘導

Oshima, Nobu 24 September 2014 (has links)
Oshima N, Yamada Y, Nagayama S, Kawada K, Hasegawa S, et al. (2014) Induction of Cancer Stem Cell Properties in Colon Cancer Cells by Defined Factors. PLoS ONE 9(7): e101735. doi:10.1371/journal.pone.0101735 / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18547号 / 医博第3940号 / 新制||医||1006(附属図書館) / 31447 / 京都大学大学院医学研究科医学専攻 / (主査)教授 千葉 勉, 教授 野田 亮, 教授 武藤 学 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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