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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.
11

Urokinase-type plasminogen activator receptor contributes to chemosensitivity and epithelial-to-mesenchymal transition in PDAC / uPAR and p38 regulate autophagy dependent gemcitabine resistance in AsPC1: autophagy inhibitors and gemcitabine as a potential combined therapy for a subgroup of pancreastic cancers

Peng, Luogen 11 November 2020 (has links)
No description available.
12

Targeted squalenoyl nanomedicines for pancreatic cancer treatment / Nanoparticules à base du squalene pour le traitement ciblé du cancer du pancréas

Valetti, Sabrina 24 March 2014 (has links)
Le cancer pancréatique représente la cinquième cause de décès par cancer dans les pays occidentaux. Son mauvais pronostic (survie à 5 ans inférieure à 3,5 % des cas) est dû à l’absence de facteurs de risques spécifiques interdisant une prévention efficace, et à un diagnostic tardif qui révèle un cancer agressif chez environ 90% des patients. Actuellement, le seul traitement curatif de ce cancer est la chirurgie, mais celle-ci ne peut être envisagée que dans 10 à 15 % des cas. L’adressage de molécules thérapeutiques vers l’organe, le tissu ou la cellule malade constitue aujourd’hui un défi majeur pour le traitement des maladies humaines notamment infectieuses, cancéreuses ou d’origine génétique. C’est pour ces raisons que le développement de nanotechnologies, en tant que vecteurs de médicaments, a pris un essor considérable au cours des dernières années. Dans ce contexte, le concept de squalènisation repose sur le couplage chimique entre le squalène (SQ), un lipide naturel précurseur de la synthèse du cholestérol, et des principes actifs (notamment des molécules anticancéreuses). Les bioconjugués ainsi formés sont alors capables de s’auto-assembler en solution aqueuse pour former des nanoparticules stables de diamètres compris entre 100 et 300 nm. L’exemple de référence dans ce domaine est la nanoparticule de gemcitabine-squalène (SQdFdC) qui a donné lieu à des résultats spectaculaires in vitro sur des lignées de cellules cancéreuses humaines In vivo, les nanoparticules de gemcitabine-squalène se sont avérées beaucoup plus efficaces que la gemcitabine libre sur des tumeurs solides greffées par voie sous-cutanée ainsi que sur des modèles murins de leucémies agressives métastatiques.Au vu de ces résultats encourageants, le projet de thèse a été développé autour de deux axes de recherche. (I) Dans un premier temps, les nanoparticules de gemcitabine-squalène ont été fonctionnalisées par un peptide capable de reconnaître et de cibler spécifiquement les cellules cancéreuses pancréatiques. (II) Le deuxième axe de recherche a visé l’encapsulation d’un second principe actif au sein des nanoparticules de gemcitabine-squalène afin de développer le concept de nanoparticule « multi-thérapeutique ». / Pancreatic cancer is a lethal disease with the worst prognosis among all solid tumors. In the last decades, progresses in pancreatic cancer therapy had remained exceedingly slow and disappointing offering minimal benefits in median survival which remains of less than 6 months and the maximum of 5 years in the 6% of patients. One of the major requirements for a successful cancer therapy is its ability to selectively kill cancer cells with minimal damage to healthy tissues. In this context, a great deal of attention focused on advanced nanoscale systems (i.e., nanomedicines) with the aim to overcome the limits associated to the traditional drug delivery modalities. Nanomedicines can indeed enhance drug properties by (i) offering protection from degradation, (ii) enabling controlled release and distribution and increasing bioavailability while reducing undesired side effects.In the current work we aimed to propose novel nanoscale-based strategies to optimize pancreatic cancer treatment taking into account the specific physio-pathology of this tumor. The first approach relied on the design of a targeted nanomedicine able to specifically bind receptors mainly expressed onto pancreatic cancer cells in order to selectively increase drug accumulation in these cells saving healthy ones.In a second approach, by combining two therapeutic agents in the same nanoparticle we constructed a multi-therapeutic drug delivery system capable to increase the therapeutic index of the combined therapy. In particular, taking advantages from the “squalenoylation prodrug approach”, the research activity of this Ph.D. work lead to the to design of (i) a novel peptide-functionalized squalenoyl gemcitabine nanoparticle and (ii) a tyrosine kinase inhibitor-loaded squalenoyl gemcitabine nanoparticle. Obtained nanoparticles were investigated with respect to their physico-chemical properties and in vitro antitumor activity. The efficacy of peptide-functionalized nanoparticles in impairing tumor growth was assessed in vivo on an experimental model of pancreatic cancer.
13

Nouveau concept de resensibilisation à la chimiothérapie en activant la nucléoside kinase dCK par le masitinib, un inhibiteur de protéines tyrosine kinases / New concept of resensitization to chemotherapy by activating the nucléoside kinase dCK by masitinib, a protein tyrosine kinase inhibitor.

Hammam, Kahina 24 November 2014 (has links)
La résistance à la chimiothérapie constitue un frein majeur à son efficacité. Notre équipe a récemment pu montrer que le masitinib, un nouvel inhibiteur de protéines tyrosine kinases, possède une activité de resensibilisation des cellules tumorales résistantes à la chimiothérapie lorsqu'il est combiné à certaines chimio-drogues. L'objectif des travaux de cette thèse est de déterminer les voies de signalisation, modulées par l'action du masitinib, qui sont impliquées dans la resensibilisation aux chimiothérapies et amélioration de l'activité anti-tumorale.Dans la première partie de la thèse, nous avons pu identifier la nucléoside kinase dCK (désoxycytidine kinase), protéine activatrice d'un grand nombre de chimiothérapies, comme nouvelle cible du masitinib. Cette première étude nous a permis de mettre en évidence un nouveau concept thérapeutique: le masitinib, un composé chimique de type inhibiteur de protéines tyrosine kinases, peut jouer en même temps le rôle d'activateur de nucléoside kinase.Nous avons pu mettre en évidence dans la deuxième partie de la thèse que le traitement combiné entre l'épi-drogue décitabine et le masitinib peut être plus efficace pour la réexpression de certains gènes non ou peu induits par la décitabine seule.En conclusion, ces travaux nous ont permis de mettre en évidence l'interaction entre un inhibiteur de protéine tyrosine kinases et une nucléoside kinase, dans un concept d'activation enzymatique qui pourra certainement servir de base pour l'élaboration de nouvelles petites molécules chimiques spécifiques de l'activation de dCK ou d'autres nucléosides kinases nécessaires à l'activation des drogues de chimiothérapie. / Resistance to chemotherapy is considered as one of the major blockers of its efficacy. Recently, our team demonstrated that masitinib, a new tyrosine kinases inhibitor, possesse a resensitization activity of cell lines resistant to chemotherapy when associated with chemodrugs.The aim of this work is to determine signaling pathways, modulated by masitinib action, that could explain the resensitization to chemotherapy and improvement of anti-tumoral activity.In the first part of this work, we identified the nucleoside kinase dCK (deoxycytidine kinase), a chemotherapy activating protein, as a new target of masitinib. In summary, this first part of the work allowed us to describe a new and never described concept: masitinib, a small molecule belonging to tyrosine kinases group, can also play a role as nucleoside kinase activator.We were able to demonstrate through the second part of the work that the combined treatment of the epidrug decitabine and masitinib can be more effective than decitabine treatment for the re-expression of some genes non or weakly induced by decitabine when used alone.In conclusion, These data allowed us to introduce an interaction between a tyrosine kinases inhibitor and a nucleoside kinase, as an enzymatic activation new concept. This could be used as a base for the design of new small chemical molecules specific for dCK or other nucleoside kinases essential for the activation of chemodrugs. This concept will obviously help to imagine and evaluate more potential therapeutic combinations of chemodrugs and small chemical molecules to overcome the resistance to chemotherapy dependent on nucleoside kinases.
14

Technique de perfusion pulmonaire isolée de chimiothérapie chez le porc / Isolated lung perfusion with chemotherapy in a pig model

Pagès, Pierre-Benoît 03 July 2014 (has links)
Introduction : La perfusion pulmonaire isolée (PPI) est une technique expérimentale dont l’objectif est d’administrer de fortes doses de chimiothérapie dans le poumon sans effets secondaires systémiques. Cette thèse s’est déroulée en trois étapes : première étape, déterminer in vitro la chimiothérapie la plus efficace en 30 minutes sur les cellules de cancers colo-rectaux (CCR). Deuxième étape, mettre au point la technique de PPI chez le porc. Troisième étape, mener une étude d’escalade de dose de chimiothérapie chez le porc en PPI.Méthodes : Première étape, des tests de cytotoxicité in vitro ont été menés sur un panel de cellules d’adénocarcinome colique humain avec les drogues de chimiothérapie les plus efficaces dans les essais cliniques. Deuxième étape, des porcs étaient traités par perfusion de chimiothérapie dans le poumon gauche isolé de la circulation générale pendant 30 minutes puis maintenus en vie pendant un mois. Troisième étape, les doses de chimiothérapie injectés étaient augmentées par palier jusqu’à obtenir une toxicité aigüe ou le décès des animaux.Résultats : La gemcitabine (GEM) fut la drogue ayant la plus grande efficacité anti-tumorale pour un traitement de 30 min. La PPI de GEM permit d’obtenir des concentrations élevées de GEM dans le parenchyme pulmonaire et la survie des animaux pendant un mois. Il n’existait pas de fuites systémiques de GEM. L’augmentation des doses de GEM permis de déterminer la dose maximale toxique à 320 mg et la toxicité limitant la dose à 640 mg. Conclusions : La technique de PPI avec la GEM est une technique sûre et reproductible permettant d’obtenir de fortes concentrations de GEM dans le parenchyme pulmonaire. / Introduction: The isolated lung perfusion (ILP) is an experimental technique which main objective is to deliver high dose of cytotoxic agent to the lung tissue without systemic exposure. The thesis took place in three stages: first stage, setting in vitro the chemotherapy the most efficient against colorectal cancer (CCR) cells in 30 min. Second stage, develop the ILP technique in a pig model. Third stage, lead a dose escalation study with chemotherapy by ILP.Methods: First stage, efficacy of various cytotoxic molecules against a panel of human CCR cell lines was tested in vitro after a 30-minute exposure. Second stage, pigs were treated with chemotherapy delivered by ILP during 30 minutes and kept alive during a month. Third stage, chemotherapy doses were increase in order to obtain acute toxicity or death of animals.Results: Gemcitabine (GEM) was the most efficient drug against CCR cells in 30 minutes. ILP with GEM permit to maintain high concentration in the lung parenchyma and pigs survival during one month. No systemic leaks were detected. Dose increase of GEM conduct to determine the maximal tolerated dose of GEM by ILP to 320 mg. Conclusions: ILP with GEM is a safety and reproducible technique allowing high GEM concentrations in the lung tissue.
15

Knockout studies of Panc1 cells / Knockout studier av Panc1 celler

Sundin, Martin January 2021 (has links)
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal form of cancerwith very few available treatment options of which none has great effect.Cancer cells and stromal cells such as stellate cells which exist in abundancein PDAC interact by crosstalk, resulting in a tumorigenic collective response.With the help of a previously developed 3D co-culture spheroid model theeffect of a CRISPR/cas9 knockout of the cellular communication cetworkfactor 1 (CCN1) gene together with gemcitabine (GEM) treatment has beeninvestigated in terms of Panc1 cell viability and gene expression. Spheroidsconsisting of wild-type and knockout cell lines, each identified by westernblots were cultured, imaged and treated. Viability assays and RNA extractionfollowed by PCR showed that the viability of the cancer cells in the spheroidswere higher for the cells with CCN1 knockout. Cancer cells were also coculturedwith stellate cells with the goal of investigating the effect of thecellular crosstalk on chemoresistance. / Pankreatisk duktal adenokarcinom (PDAC)  är en ytterst dödlig form av cancermed få tillgängliga behandlingsalternativ, varav ingen är särskilt effektiv.Cancerceller och stromala celler så som de stellatceller som rikligt förekommeri PDAC interagerar med varandra genom överhörning, vilket leder till en effektsom hjälper tumören att proliferera. Effekten av en CRISPR/cas9 knockoutav genen CCN1 tillsammans med behandling med gemcitabin vad gällercellviabilitet och genuttryck studerades med hjälp av en tidigare utveckladfleratig sfäroidmodell. Sfäroider, bestående av vildtypceller och knockoutcellerlinjersom identifierades med western blots, odlades, fotades och behandlades.Viabilitetstester och extraktion av RNA följt av PCR visade att viabilitetenav cancerceller i sfäroiderna var högre för de celler som var knockout.Cancerceller samodlades även med stellatceller med målet att undersökaeffekten av cellernas överhörning på motståndet mot kemoterapi.
16

Identificação de alvos moleculares associados à resistência a gemcitabina e  análogos de rebecamicina usando Saccharomyces cerevisiae como modelo celular / Identification of molecular targets related to the resistance to gemcitabine and to rebeccamycin analogs using Saccharomyces cerevisiae as model cell

Lucas de Sousa Cavalcante 25 September 2013 (has links)
O câncer é uma das principais causas de mortalidade em todo o mundo. O envelhecimento da população mundial, especialmente nos países em desenvolvimento, indica que esse índice tende a aumentar a cada ano. Como o câncer é uma doença complexa, uma melhor compreensão dos mecanismos moleculares envolvidos na carcinogênese e na resposta aos tratamentos atuais são essenciais para mudar esse cenário. Gemcitabina e rebecamicina são moléculas que apresentam atividade antitumoral, sendo que a primeira é usada como agente único no tratamento de adenocarcinoma pancreático, ou em conjunto com outras drogas em vários tipos de câncer, enquanto que alguns análogos da segunda já foram utilizados em testes clínicos de fase II em câncer de mama e pulmão. A gemcitabina é um análogo de desoxicitidina que interrompe a síntese de DNA, além de apresentar efeito inibitório sobre várias proteínas, como ribonucleotídeo redutase. A rebecamicina e vários de seus análogos são indolocarbazóis que incluem moléculas intercalantes de DNA, além de inibidores da topoisomerase I e de algumas proteína quinases, como PKC e Chk1. Alguns indolocarbazóis apresentam também importante atividade antimicrobiana. Os mecanismos de resistência a essas drogas são pouco conhecidos e alguns já foram sugeridos; porém, ainda não há consenso sobre as vias celulares envolvidas. A proposta desse trabalho foi identificar genes associados às respostas a gemcitabina e análogos de rebecamicina, usando Saccharomyces cerevisiae como modelo celular. Avaliamos a atividade biológica de nove análogos de rebecamicina sintéticos, destacando o composto mais promissor para estudos mais aprofundados. Por meio de análise direta de fenótipo em escala genômica, identificamos genes cuja deleção resulta em hipersensibilidade ao análogo de rebecamicina, dentre eles um sensor de estresse relacionado à via Pkc1/Mpk1 quinase (SLG1), uma lisina deacetilase (RPD3) e uma lisina demetilase (JHD2). Esses três genes estão relacionados a uma maior atividade de proteínas de resistência multidroga, sugerindo que diversas vias regulatórias são importantes na resposta a indolocarbazóis. Também verificamos, por análise quantitativa de fenótipo (ensaio Bar-Seq), que a deleção de genes com funções atualmente pouco relacionadas à gemcitabina conferiam maior sensibilidade a droga, como uma arginina metiltransferase (HMT1) e uma subunidade do complexo Cop9 sinalossomo (CSI1), o qual está relacionado a regulação da atividade de diversas proteínas, incluindo ribonucleotídeo redutase. Em conjunto, nossos resultados demonstram que vias ainda não relacionadas a resposta a esses compostos podem ser de grande contribuição para a compreensão dos mecanismos de resistência aos mesmos, auxiliando no desenvolvimento de novos tratamentos e fármacos. / Cancer is one of the main causes of death throughout the world. Population aging, especially in developing countries, points to an increase in cancer incidence over the coming years. As cancer is a complex disease, a better understanding of the mechanisms involved in carcinogenesis and in the current treatments is essential to change this scenario. Gemcitabine and rebeccamycin are molecules that present antitumoral activity. The first one is currently used as a single agent in pancreatic cancer treatment or in combination with other drugs in several types of cancer, while analogs of the second have been tested in phase II clinical trials in breast and lung cancers. Gemcitabine is a deoxycytidine analog that inhibits DNA synthesis, and also presents inhibitory effects over several proteins, such as ribonucleotide reductase. Rebeccamycin and its analogs are indolocarbazoles which include DNA intercalant molecules, as well as topoisomerase I and protein kinase inhibitors, such as PKC and Chk1. The mechanisms related to the resistance to these drugs are poorly understood and some of them have been suggested; even though, there is no consensus about the cellular pathways involved. The aim of this work was to identify genes associated to the response to gemcitabine and rebeccamycin analogs using Saccharomyces cerevisiae as a model cell. We evaluated the biological activity of nine synthetic rebeccamycin analogs, selecting the most promising compound for deeper studies. In a genome-wide qualitative phenotypic analysis, we have identified genes whose disruption resulted in hypersensitivity to the rebeccamycin analog. Among them, we found a stress-sensor involved in Pkc1/Mpk1 kinase pathway (SLG1), a lysine deacetylase (RPD3) and a lysine demethylase (JHD2). These three genes are related to an increased multidrug resistance activity, suggesting that several regulatory pathways play a role in the response to indolocarbazoles. We also found, by means of a quantitative phenotypic analysis (Bar-Seq assay), increased sensitivity to gemcitabine in null-mutants of genes whose functions are currently poorly related to the drug, like an arginine methyltransferase (HMT1) and a subunit of Cop9 signalosome complex (CSI1), which is related to activity regulation of several enzymes, including ribonucleotide reductase. Together, our results show that pathways which were previously unrelated to the response to these compounds can be useful for a better understanding of their resistance mechanisms, providing insights into new drug development and therapy.
17

Identificação de alvos moleculares associados à resistência a gemcitabina e  análogos de rebecamicina usando Saccharomyces cerevisiae como modelo celular / Identification of molecular targets related to the resistance to gemcitabine and to rebeccamycin analogs using Saccharomyces cerevisiae as model cell

Cavalcante, Lucas de Sousa 25 September 2013 (has links)
O câncer é uma das principais causas de mortalidade em todo o mundo. O envelhecimento da população mundial, especialmente nos países em desenvolvimento, indica que esse índice tende a aumentar a cada ano. Como o câncer é uma doença complexa, uma melhor compreensão dos mecanismos moleculares envolvidos na carcinogênese e na resposta aos tratamentos atuais são essenciais para mudar esse cenário. Gemcitabina e rebecamicina são moléculas que apresentam atividade antitumoral, sendo que a primeira é usada como agente único no tratamento de adenocarcinoma pancreático, ou em conjunto com outras drogas em vários tipos de câncer, enquanto que alguns análogos da segunda já foram utilizados em testes clínicos de fase II em câncer de mama e pulmão. A gemcitabina é um análogo de desoxicitidina que interrompe a síntese de DNA, além de apresentar efeito inibitório sobre várias proteínas, como ribonucleotídeo redutase. A rebecamicina e vários de seus análogos são indolocarbazóis que incluem moléculas intercalantes de DNA, além de inibidores da topoisomerase I e de algumas proteína quinases, como PKC e Chk1. Alguns indolocarbazóis apresentam também importante atividade antimicrobiana. Os mecanismos de resistência a essas drogas são pouco conhecidos e alguns já foram sugeridos; porém, ainda não há consenso sobre as vias celulares envolvidas. A proposta desse trabalho foi identificar genes associados às respostas a gemcitabina e análogos de rebecamicina, usando Saccharomyces cerevisiae como modelo celular. Avaliamos a atividade biológica de nove análogos de rebecamicina sintéticos, destacando o composto mais promissor para estudos mais aprofundados. Por meio de análise direta de fenótipo em escala genômica, identificamos genes cuja deleção resulta em hipersensibilidade ao análogo de rebecamicina, dentre eles um sensor de estresse relacionado à via Pkc1/Mpk1 quinase (SLG1), uma lisina deacetilase (RPD3) e uma lisina demetilase (JHD2). Esses três genes estão relacionados a uma maior atividade de proteínas de resistência multidroga, sugerindo que diversas vias regulatórias são importantes na resposta a indolocarbazóis. Também verificamos, por análise quantitativa de fenótipo (ensaio Bar-Seq), que a deleção de genes com funções atualmente pouco relacionadas à gemcitabina conferiam maior sensibilidade a droga, como uma arginina metiltransferase (HMT1) e uma subunidade do complexo Cop9 sinalossomo (CSI1), o qual está relacionado a regulação da atividade de diversas proteínas, incluindo ribonucleotídeo redutase. Em conjunto, nossos resultados demonstram que vias ainda não relacionadas a resposta a esses compostos podem ser de grande contribuição para a compreensão dos mecanismos de resistência aos mesmos, auxiliando no desenvolvimento de novos tratamentos e fármacos. / Cancer is one of the main causes of death throughout the world. Population aging, especially in developing countries, points to an increase in cancer incidence over the coming years. As cancer is a complex disease, a better understanding of the mechanisms involved in carcinogenesis and in the current treatments is essential to change this scenario. Gemcitabine and rebeccamycin are molecules that present antitumoral activity. The first one is currently used as a single agent in pancreatic cancer treatment or in combination with other drugs in several types of cancer, while analogs of the second have been tested in phase II clinical trials in breast and lung cancers. Gemcitabine is a deoxycytidine analog that inhibits DNA synthesis, and also presents inhibitory effects over several proteins, such as ribonucleotide reductase. Rebeccamycin and its analogs are indolocarbazoles which include DNA intercalant molecules, as well as topoisomerase I and protein kinase inhibitors, such as PKC and Chk1. The mechanisms related to the resistance to these drugs are poorly understood and some of them have been suggested; even though, there is no consensus about the cellular pathways involved. The aim of this work was to identify genes associated to the response to gemcitabine and rebeccamycin analogs using Saccharomyces cerevisiae as a model cell. We evaluated the biological activity of nine synthetic rebeccamycin analogs, selecting the most promising compound for deeper studies. In a genome-wide qualitative phenotypic analysis, we have identified genes whose disruption resulted in hypersensitivity to the rebeccamycin analog. Among them, we found a stress-sensor involved in Pkc1/Mpk1 kinase pathway (SLG1), a lysine deacetylase (RPD3) and a lysine demethylase (JHD2). These three genes are related to an increased multidrug resistance activity, suggesting that several regulatory pathways play a role in the response to indolocarbazoles. We also found, by means of a quantitative phenotypic analysis (Bar-Seq assay), increased sensitivity to gemcitabine in null-mutants of genes whose functions are currently poorly related to the drug, like an arginine methyltransferase (HMT1) and a subunit of Cop9 signalosome complex (CSI1), which is related to activity regulation of several enzymes, including ribonucleotide reductase. Together, our results show that pathways which were previously unrelated to the response to these compounds can be useful for a better understanding of their resistance mechanisms, providing insights into new drug development and therapy.
18

Exploring the Immunogenicity and Therapeutic Applications of Boranophosphate-modified RNA: siRNA and RNA Aptamers

Sharaf, Mariam Lucila January 2011 (has links)
<p>Borane (BH<sub>3<sub>) chemistry offers unique chemical characteristics that enable boranophosphate (BP) oligonucleotides with potential to enhance RNA therapeutic applications such as RNA interference (RNAi) and RNA aptamers. Further, BP nucleotides are substrates for RNA polymerases which allow the enzymatic synthesis of stereoregular boranophosphate (BP)-RNA molecules of different lengths and properties. We expect that these BP-RNAs will interact in a novel way with the desired target molecules because they can coordinate with a diverse array of ligand sites in proteins or other RNA molecules. This is due to the distinct hydrophobicity, sterospecificity, and polarity properties imparted by the phosphorus-boron (P-B) chemical bond compared to the natural phosphorus-oxygen (P-O) bond. </p><p>The object of this dissertation is to explore the therapeutic applications of the BP-RNA such as siRNA, RNA aptamers, and in addition investigate the immunogenicity of this modification. We used mouse cells to determine if BP-RNA would activate toll-like receptor (TLR 7), which is involved in innate immune response to foreign single stranded RNA (ssRNA). This response is undesired when applied to oligonucleotide therapeutics such as siRNA and RNA aptamers. In terms of RNAi, it would be an advantage to have low immunogenicity and high downregulation activity by the siRNA. To determine the innate immune activation of the BP-RNA through the TLR 7 we used a known activator, the human immunodeficiency virus (HIV) derived single-stranded RNA (ssRNA40) and measured the production of cytokines as a function of the number of modified BP-linkages. The production of cytokines IL-6 and TNF&#945; was quantified after the boranophosphate (BP), phosphorothioate (PS) or natural ssRNA40 were transfected into murine macrophage Raw264.7 cells. Natural and phosphorothioate RNA (PS-RNA) have been shown to be activators of TLR 7 receptors. In contrast, we found that fully modified BP- ssRNA40 did not activate TLR 7. This is relevant in oligonucleotide applications such as siRNA and RNA aptamers where off-target effects such as immune activation after administration are not desired. </p><p>Subsequently, the low immune activation would be an advantage when coupled to RNAi activity of the oligonucleotide. Thus, we explored whether BP modified siRNA molecules would modulate gene expression and if there was an effect on downregulation activity when increasing the number of BH3 modifications on the phosphate backbone. Our therapeutic model was the multi-drug resistance 1 (MDR1) gene that expresses P-glycoprotein (P-gp), which has been notoriously difficult to modulate. The aberrant regulation of genes such as MDR1 in cancer cells are a major cause of chemotherapeutic treatment failure against human cancers. Hence, controlling the expression of cancer genes with antisense technology is a possible cancer therapy. Specifically, correcting the overexpression of p-glycoprotein using modified siRNAs that target and degrade the P-glycoprotein mRNA produced by the MDR1 gene. We found that there is a reduction of siRNA activity with an increasing number of BP-modifications. It appears that there is a fine balance between lack of immune response and gene downregulation when applied to BP-siRNA. </p><p>Finally, we compared the enrichment during the Systematic Evolution of Ligands by EXponential enrichment (SELEX) method of two libraries, one BP-RNA (U&#945;B) compared to a doubly-modified RNA (2'FC & U&#945;B), against a human thrombin. Aptamers modulate protein activity and interfere with protein signaling by binding to the desired protein with high affinity and specificity leading to their use in therapeutic applications where protein activity needs to be controlled or it is anomalous. In the case of blood coagulation, thrombin plays a central role in coagulation signaling cascade and it is a good target to use to control blood coagulation in clinical settings. We attempted to optimize the selection of BP- RNA aptamers through 4-8 rounds of SELEX against the protein thrombin. We found that the selection conditions were not optimal for BP-RNA SELEX possibly due to non-specific binding to a bovine serum albumin (BSA) in the selection buffer.</p> / Dissertation
19

Combining gemcitabine with checkpoint kinase inhibitors to sensitize pancreatic tumors

Saini, Priyanka 13 October 2014 (has links)
No description available.
20

Informed Decision Making for Patients with Advanced Pancreatic Cancer Considering Chemotherapy: Development and Evaluation of a Clinical Decision Aid for Patients

Gresham, Gillian January 2013 (has links)
Pancreatic cancer is the fourth leading cause of cancer death in Canada. Significant advancements in chemotherapy for advanced pancreatic cancer have resulted in the need for a quantitative comparison between these treatments on a relative scale. Therefore, a systematic review and Bayesian network meta-analysis of randomized clinical trials was conducted using gemcitabine, the standard treatment, as the reference comparator. Based on results from the network meta-analysis, in which optimal treatments were identified and side effects of each treatment evaluated, an Internet-based patient decision aid was developed in order to present the benefits and risks of each therapy option: (1) Best supportive care (2) gemcitabine (3) FOLFIRINOX. The objective of the decision aid was to guide patients through the decision-making process based on their individual preferences and values. The decision aid was deemed to be acceptable and feasible based on results from a pilot study conducted at The Ottawa Hospital Cancer Centre.

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