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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.
51

Étude des effets anticancéreux de polyphénols d'origine naturelle : rôle essentiel des espèces réactives de l'oxygène et des gènes suppresseurs de tumeurs / Study of the anti-cancer effects of natural polyphenols : key role of reactive oxygen species and tumor suppressor genes

Sharif, Tanveer 23 October 2012 (has links)
Ce travail de recherche montre que les différentes sources de polyphénols (polyphénols de vin rouge, jus d'aronia melanocarpa, jus de cassis) ont de puissants effets chemothérapeutiques et chemopréventifs sur différentes lignées de culture cellulaires, mais également in vivo sur un modèle de tumorigenèse. Ces polyphénols inhibent la prolifération des cellules cancéreuses (leucémie lymphoblastique aigüe, cellules souches) en induisant un arrêt du cycle cellulaire et l'apoptose. Les effets anti-cancéreux sont dépendants de l' induction du stress oxydatif mettant en jeu les anions superoxydes et le peroxyde d·hydrogène qui à son tour, activent les voies de signalisation conduisant à une surexpression des gènes suppresseurs de tumeurs comme p73 et p53 et ainsi que caspase 3. Celle étude montre également que les polyphénols contrôlent la prolifération des cellules cancéreuses au niveau épigénétique en diminuant l'expression d'UHRF1 (un intégrateur épigénétique de prolifération). Cependant l'effet anticancéreux de ces polyphénols est sélectif et agit sur les cellules cancéreuses et non sur les cellules normales. Le fractionnement de ces sources riches en polyphénols et les études menées en utilisant des composés purs montrent que les effets anticancéreux sont attribués à plusieurs composés différents. Cette étude montre l' identification de cyanidine-3-glucoside et de cyanidine-3-rutinoside comme source de composés anticancéreux actifs. / This research work shows that different sources of polyphenols (RWPs, AMJ and blackcurrant) have strong chemotherapeutic and chemopreventive effects on several cancer cells lines (acute lymphoblastic leukemia and cancer stem cells) and also in vivo in a model of tumorigenesis in mouse. These polyphenols inhibit the proliferation of various cancer cells by inducing cell cycle arrest and apoptosis. The anti-cancer effect is dependent on the induction of oxidative stress involving superoxide anions and hydrogen peroxide which, in turn, activate the signaling pathways leading to the re-expression of tumor suppressor genes such as p73 and p53 and executor of apoptosis such as caspase 3. This study also shows that polyphenols control the proliferation of cancer cells at epigenetic level by decreasing the expression of UHRF1 (an epigenetic integrator of proliferation). Moreover, the anticancer effect of these polyphenols is selective towards cancer cells and not in normal cells. Fractionation of these rich sources of polyphenols and studies on the commercially available pure products shows that anti-cancer effects of these polyphenols involve several different compounds. This study leads to the identification of cyaniding-3-O-glucoside and cyaniding-3-O-rutinoside as active anticancer compounds.
52

Synthèse par ingénierie métabolique d'oligosaccharides sialylés pour l'élaboration de glycoconjugués d'intérêt médical / Sialylated oligosaccharides synthesis by metabolic engineering for glycoconugate preparation

Richard, Emeline 17 February 2017 (has links)
Les structures sialylées sont présentes à la surface des cellules sous forme de glycoconjugués,couplés à des protéines ou des lipides. Ces structures jouent un rôle important dans divers processusbiologiques que ce soit à travers l’interaction avec des lectines, ou de par leurs propriétés physicochimiques.Ces structures sont également impliquées dans diverses pathologies et on constatenotamment une forte augmentation du taux d’acides sialiques chez les individus atteints de cancer,due à une surexpession de structures naturelles mais aussi à l’apparition de nouveaux motifs,naturellement absent chez l’individu sain. L’ensemble de ces structures sialylées présente un intérêtsoit par leur rôle biologique soit à cause de leur expression spécifique dans les cancers. Leurobtention est très difficile par voie chimique et la synthèse enzymatique in vitro est efficace mais trèscoûteuse en nucléotide-sucre et ne sont pas adaptées à une production à l'échelle préparative.Dans un premier temps, ces travaux de thèse s’intéressent à la synthèse bactérienne par ingénieriemétabolique d'acides polysialiques fonctionalisés. Ces polysaccharides présentent divers intérêts.Tout d’abord il est possible de les coupler à des protéines actives pour en augmenter le temps dedemi-vie in vivo. Mais ces polysaccharides peuvent également être utilisés dans le cadre de thérapievaccinale, soit contre des bactéries pathogènes de types Neisseria meningitidis qui le présententcomme polysaccharide capsulaire, soit contre les cellules cancéreuses surexprimant cette structure.Ensuite nous avons cherché à obtenir des oligosaccharides spécifiques des cancers, les motifssialylTn, et siallTF, toujours par ingénierie métabolique d’E. coli. Le sialylTn a été couplé à uneplateforme peptidique immunogène afin de construire un candidat vaccin qui a été testé in vitro et invivo sur la souris. / Sialylation is an important feature of glycolipids and glycoproteins of animal cell surfaces. Sialylatedmotifs are involved in many biological processes through lectin interactions or because of theirphysico-chemical properties. There is a great variety of sialylated structural motifs, and in manycases, there is a structure-relationship between the sialylated profile of and some pathologicprocesses. In cancer, there is an increase of sialylation including the apparition of newly andspecifically related sialylated structures belonging to the so-called tumor-associated carbohydrateantigens (TACA). Those structures present a particular interest, but their chemical or chemoenzymaticsynthesis is costly and quite unappropriated for preparative scale.This work addresses to the bacterial synthesis of sialylated motifs through the metabolic engineeringof Escherichia coli. The first part of the thesis deals with the biosynthesis of polysialylatedconjugatable motifs. Those motifs present various biological properties, such as an increase of thelife-time of therapeutic proteins; they also belong to the TACA family since over-expressed incancers. In addition, some of them are bacterial-specific motifs such as in pathogenic Neisseriameningitidis. Altogether, polysialylated conjugates can be useful for the synthesis of therapeuticdrugs and vaccines. The second part of the thesis describes a new way of producing sialylated Tn andTF carbohydrate antigens by metabolic engineering. The sialylTN motif was coupled to a peptidic andimmunogenic scaffold being a potential vaccine candidate, and its ability of raising specific antibodieswas assayed in mouse.
53

Bio-analytical study of plants used in traditional medicine in Togo / Étude bio-analytique de plantes utilisées en médecine traditionnelle au Togo

Tittikpina, Nassifatou Koko 19 September 2017 (has links)
L'étude des plantes utilisées en médecine traditionnelle au Togo est compliquée à cause de l’absence de matériel de pointe. L'identification assistée par ordinateur de produits basés sur des utilisations en médecine traditionnelle (CAPITURE) a été évaluée dans le cadre d'une enquête ethnobotanique sur le traitement traditionnel des maladies fongiques dans la Préfecture de Tchamba (Togo). Cette méthode a prédit et identifié les plantes les plus biologiquement actives parmi les 43 espèces recensées au cours de l’enquête : Pterocarpus erinaceus prédit être plus actif contre les champignons, et Daniellia oliveri contre les bactéries. Les plantes ont ensuite été testées contre les champignons, les bactéries et les cellules cancéreuses. Comme prédit par CAPITURE, P. erinaceus était plus actif contre les champignons et D. oliveri contre les bactéries. Fait intéressant, les deux plantes ont présenté une activité sur les cellules cancéreuses sans être toxique pour les cellules humaines normales. Dans une troisième étape, en utilisant la chimie analytique, les composés responsables des activités biologiques ont été identifiés. La plupart de ces composés n'ont jamais été signalés dans les espèces végétales ou dans la nature, avec une activité biologique dans la gamme micro-molaire. Enfin, en réduisant la poudre des organes végétaux à la taille de nano-particules, une meilleure activité biologique a été observée par rapport à celle de l'extrait organique. En conclusion, cette recherche a mené à la découverte de nouvelles molécules avec une activité biologique intéressante, molécules qui nécessiteront une étude approfondie et détaillée / The investigation of plants used for traditional medicine in Togo is complicated as modern techniques are not available. Computer-aided product identification from traditional usage records (CAPITURE) was evaluated in the context of an ethnobotanical survey on the traditional treatment of fungal diseases in Tchamba District (Togo). This method predicted and identified the most biologically active plants out of the 43 species survey-recorded: Pterocarpus erinaceus predicted to be more active against fungi and Daniellia oliveri against bacteria. The plants were then tested against fungi, bacteria and cancer cells. As predicted with CAPITURE, P. erinaceus was more active against fungi and D. oliveri against bacteria. Interestingly, both plants presented activity on cancer cells without being toxic to normal human cells. In a third step, using analytical chemistry, the compounds responsible for the biological activities were identified. Most of those compounds have never been reported in the plant species or in nature at all, with biological activity in the micromolar range. Finally, pharmaceutical technology was used: by nanosizing the powder of the plant organs, a better biological activity was observed in comparison to that of the organic extract. In conclusion, this research led to the discovery of new molecules with an interesting biological activity that will need further and more detailed investigation
54

Effectiveness of a closed system device in reducing occupational exposure and environmental concentrations of anticancer drugs

Vyas, Nitin January 2014 (has links)
Owing to their non-selective nature, anti-cancer drugs affect both cancerous and non-cancerous cells and present a major health risk to healthcare staff working with them. This project was conducted at Derriford Hospital, Plymouth, to investigate the extent of contamination with anti-cancer drugs on work surfaces and the environmental emissions of these drugs. In the Isolator study, surface contamination arising from the preparation of five anticancer drug infusions (epirubicin, fluorouracil, cisplatin, oxaliplatin and carboplatin) in a pharmaceutical isolator and external surfaces of infusion bags and syringes using a conventional syringe and needle technique was investigated and compared with that obtained using a closed system drug transfer device (Tevadaptor). Wipe samples were taken for a period of one week from pre-defined areas in a pharmaceutical isolator and from the surface of prepared Intra-Venous (IV) infusion bags and pre-filled syringes to obtain baseline data. Gloves and preparation mats used during this period were also collected. Following a one-week operator familiarisation period, the Tevadaptor device was then introduced for cytotoxic preparation and wipe-sampling of surfaces and collection of consumables was continued for a further week (intervention period). The samples obtained were then analysed by HPLC and ICP-MS. The baseline contamination data from Tevadaptor isolator study was undetected to 0.9 ng cm-2 (epirubicin), undetected to 3.58 ng cm-2 (5-FU) and 0.05-0.92 ng cm-2 (Pt) in the wipe samples from the pharmaceutical isolator surfaces; amounts on glove samples were 1100-6100 ng/glove (epirubicin), 300-8100 ng/glove (5-FU) and 1-6 ng/glove (platinum). During the intervention phase isolator surface contamination was not detected in all samples for 5-FU and epirubicin and platinum was detected on the isolator surfaces in the range of 0.002-0.09 ng cm-2. The use of Tevadaptor resulted in a reduction of contamination on external surfaces by a factor of 10 or more for all marker drugs. A ward study investigated the surface contamination in the oncology out-patient department caused by cisplatin, oxaliplatin, carboplatin and gemcitabine. The study compared the effect of using the Tevadaptor to prepare and administer anticancer drugs infusions on ward surface contamination to the current UK standard practice. A questionnaire was also distributed to participating staff members to assess the user-friendliness of Tevadaptor. Wipe samples were taken from pre-defined areas from the oncology out-patients department and gloves used by nursing staff for assembly and administration of the above drugs were also collected. Sample collection followed a similar schedule to the Tevadaptor isolator study. The baseline ward surface contamination ranged from undetected to 4.97 ng cm-2 (gemcitabine) and 3.1 ng cm-2 (platinum). In the case of gloves used by nursing staff the levels of contamination ranged from undetected to 1251 ng/glove (gemcitabine) and 405.4 ng/glove (platinum). The contamination on ward surfaces during the intervention phase ranged from undetected to 3.21 ng cm-2 (gemcitabine) and 2.69 ng cm-2 (platinum) and contamination levels on gloves ranged from undetected to 9252 ng/glove (gemcitabine) and 1319 ng/glove (platinum). During the intervention phase there was a reduction in frequency of contamination, even though the total amount of surface contamination by anticancer drugs did not always decrease in comparison to baseline data, presumably due to unaccounted spillages. A drain study investigated the presence of platinum in hospital wastewater as a measure of contamination caused by the excretion of platinum-based anticancer drugs by patients. Platinum was measured over a three week period in one of the main drains and in the effluent of the oncology ward. The study showed the presence of measurable quantity of platinum which ranged from 0.02 to 140 μg L-1 in the oncology effluent and 0.03 to 100 μg L-1 in the main drain. Data from this study was coupled with published measurements on the removal of the drugs by conventional sewage treatment and then concentration of platinum arising from each drug was predicted in recipient surface waters as a function of water flow rate. Although predicted concentrations were below EMEA guidelines warranting further risk assessment, the presence of potentially carcinogenic, mutagenic and teratogenic substances in surface waters is cause for concern. The results showed that a closed system drug transfer device (CSTD) used in conjunction with an isolator is highly efficient in reducing surface contamination with anti-cancer drugs. However, despite current best practice contamination on ward surfaces remained even after the use of a CSTD. Nursing as well as healthcare staff should be educated of these results and the risks of occupational exposure to low levels of anti-cancer drugs and the use of PPE should be emphasised. Results of the drain study form the basis of preliminary estimates of the likely concentrations of platinum-based drugs in surface waters and their potential environmental impacts.
55

Development and assessment of in vitro tumour models for anti-cancer drug testing

Liu, Xinhui January 2011 (has links)
The study of the development of anti-cancer drugs and preclinical efficacy tests has until today encountered a major problem identified as lack of reliable in vitro tumour models which are able to reflect in vivo tumour conditions. These models provide a clear basis for understanding tumour development processes, assisting in the selection of agents from various chemicals and testing the efficacy of drugs. There are two important characteristics for an in vitro tumour model, i.e. tumour-like structure of cell aggregates, and the in vivo-like culture microenvironment. To meet these two requirements, an in vitro perfusion based three-dimensional tumour model was developed for the three dimensional culture of cancer cells and related anti-cancer drugs tests. In order to assess this model, DLD1 and NCI/ADR cells were cultured in four different models and compared their proliferation rate, cell viability, micro tumour formation and drug responses. In addition, the comparison of static and perfusion culture were done on monolayer and in 3D also. The cells in perfusion culture showed higher proliferation rates and significantly, higher cell viabilities after a 6-day culture compared to statically cultured cells, especially for the cells in the 3D culture. Microtumours (MTs) were formed from this model, which showed significant tumour-like morphological characteristics, a denser and highly stable structure, a higher cell viability, and varied drug responses compared with spheroids. The inhibition effect of paclitaxel and cisplatin, two common type anti-cancer drugs, were tested and a comparative study was carried out using conventional two-dimensional (2D) static culture, spheroids, and the developed 3D MTs model, as well as real human tumour tissues. The results showed that the cells in 2D culture were most greatly inhibited while human tumours showed the lowest drug responses. The efficacy of anti-cancer drugs, tested in conventional 2D static culture, was greatly amplified. Besides, the response of MTs to agents was much closer to that of human tumours, when the values of spheroids are relatively closer to the cells in 2D culture. It is further supported that MTs have more tumour-like characteristics than spheroids. When compared, the inhibition to proliferation of cells in static and perfusion culture showed significantly different drug responses except for the cells on the monolayer. The shown difference between static and perfusion culture can be due to the different culture environment, and further related to the different action mechanisms of anti-cancer agents. The perfusion culture provides a more homogenous and more physiological microenvironment for the in vitro tumour growth, and in vitro perfused 3D cancer model, developed in this thesis, proved valuable for the study of in vitro cancer and related anti-cancer drug tests.
56

DEVELOPMENT OF HINT BASED COMPUTATIONAL TOOLS FOR DRUG DESIGN: APPLICATIONS IN THE DESIGN AND DEVELOPMENT OF NOVEL ANTI-CANCER AGENTS

Tripathi, Ashutosh 15 July 2009 (has links)
The overall aim of the research is to develop a computational platform based on HINT paradigm for manipulating, predicting and analyzing biomacromolecular-ligand structure. A second synergistic goal is to apply the above methodology to design novel and potent anti-cancer agents. The crucial role of the microtubule in cell division has identified tubulin as an interesting target for the development of therapeutics for cancer. Pyrrole-containing molecules derived from nature have proven to be particularly useful as lead compounds for drug development. We have designed and developed a series of substituted pyrroles that inhibit growth and promote death of breast tumor cells at nM and μM concentrations in human breast tumor cell lines. In another project, stilbene analogs were designed and developed as microtubule depolymerizing agents that showed anti-leukemic activity. A molecular modeling study was carried out to accurately represent the complex structure and the binding mode of a new class of tubulin inhibitors that bind at the αβ-tubulin colchicine site. These studies coupled with HINT interaction analyses were able to describe the complex structure and the binding modes of inhibitors. Qualitative analyses of the results showed general agreement with the experimental in vitro biological activity for these derivatives. Consequently, we have been designing new analogs that can be synthesized and tested; we believe that these molecules will be highly selective against cancer cells with minimal toxicity to the host tissue. Another goal of our research is to develop computational tools for drug design. The development and implementation of a novel cavity detection algorithm is also reported and discussed. The algorithm named VICE (Vectorial Identification of Cavity Extents) utilizes HINT toolkit functions to identify and delineate a binding pocket in a protein. The program is based on geometric criteria and applies simple integer grid maps to delineate binding sites. The algorithm was extensively tested on a diverse set of proteins and detects binding pockets of different shapes and sizes. The study also implemented the computational titration algorithm to understand the complexity of ligand binding and protonation state in the active site of HIV-1 protease. The Computational titration algorithm is a powerful tool for understanding ligand binding in a complex biochemical environment and allows generating hypothesis on the best model for binding.
57

Clinical Pharmacology of MS-275, A Histone Deacetylase Inhibitor

Acharya, Milin R. 01 January 2005 (has links)
The goal of this escalating single-dose phase I research study was to determine the safety, tolerability, pharmacokinetics, pharmacodynamics as well as in vitro metabolism and plasma protein binding of MS-275, a novel histone deacetylase inhibitor, in patients with solid tumors and lymphomas. A validated LC/MS assay was developed to quantitate MS-275 in plasma, human liver microsomes and urine. The pharmacokinetic (PK) evaluation was done using a non-compartmental approach. In-vitro plasma protein binding profile of MS-275 was characterized by a validated micro-equilibrium dialysis method. In vitro phase I and phase II hepatic metabolism of MS-275 were evaluated using human liver microsomes. A correlative covariate analysis was performed in an effort to explain the wide inter-individual variability among patients.Results from the study demonstrate that the validated LC-MS assay is specific, accurate, precise and sensitive. MS-275 demonstrates a substantial inter-individual PK variability in systemic exposure and clearance; exposures increase in near-proportion, while peak concentrations increase more than-proportionally with an increase in dose. Mean apparent oral clearance (CL/F) is independent of dose and exhibits apparent dose-independent PK behavior over the studied dose range. Oral absorption is highly variable. MS-275 has a 50-fold longer half-life in humans compared to pre-clinical species. PK/PD analysis showed significant correlation between occurrence of DLT and higher systemic exposures. Although there was an increase in the acetylation of histone H3 and H4 over time, preliminary analysis showed no significant correlation between PK parameters and change in % histone acetylation after 24 hours. MS-275 is moderately bound to plasma proteins. Hepatic phase I and II metabolic pathways are only minor routes of elimination, and MS-275 is neither a substrate for liver-specific organic anion transporting proteins, OATP1B1 and OATP1B3, nor a substrate for gastrointestinal efflux transporters ABCB1 (P-gp) or ABCG2. No significant correlation was found between CL/F and demographic, body measures and other clinical covariates, and inter-patient variability in CL/F remained similar in magnitude even after correcting dose for body surface area (BSA) or other body measures. BSA is not a significant predictor of MS-275 PK, and flat-fixed dosing can be used in the future.
58

Vliv inhibice SH3 domény proteinu Crk na invazivitu nádorových buněk / The effect of Crk SH3domain inhibition in invasiveness of cells

Tomášová, Lea January 2015 (has links)
Protooncogene Crk was found to be upregulated in tumours with aggressive and invasive potential. The adaptor protein Crk has an important role in cell signaling: it integrates signals from activated integrins and growth factors receptors via its SH2 domain and transmits the signal to its SH3 domain binding partners that activate the small GTPases Rac1, Rap1 and Ras. This leads to regulation of cell migration, proliferation and survival. The aim of this thesis project was to inhibit the Crk dependent signaling by a competitive inhibition of the Crk SH3 domain, using a high affinity CrkSH3 binding peptoid. Binding of the inhibitor to the Crk SH3 domain prevents binding of cellular Crk SH3 interaction partners and the corresponding signal transmission is impaired. In this thesis project the effect of the Crk SH3 inhibition on the invasiveness of cancer cells was analyzed. The observed inhibitory effect on cell invasion as well as on anchorage independent growth provides a proof of therapeutical relevance of targeting CrkSH3N domain by peptoide-based inhibitors. Powered by TCPDF (www.tcpdf.org)
59

Explantátová kultura Juniperus virginiana L. jako perspektivní zdroj podofylotoxinu / Plant tissue culture of Juniperus virginiana L. as perspective source of podophyllotoxin

Srbová, Lenka January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Lenka Srbová Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Tissue culture of Juniperus virginiana L. as a promising source of podophyllotoxin. The diploma thesis deals with the cultivation of Juniperus virginiana tissue cultures. A growth was observed at Juniperus virginiana two years old culture (variety 'Glauca' and 'Grey Owl') after adding various concentrations of phenylalanine (1 mmol.l-1, 10 mmol.l-1 and 100 mmol.l-1 ) at selected time intervals. The results show that the highest increase in callus fresh weight was detected at Juniperus virginiana variety 'Grey Owl', particularly on the 14th day after adding 10 mmol.l-1 phenylalanine. Suspension culture was successfully derived from the Juniperus virginiana two years old callus culture (variety 'Glauca').
60

Obésité et cancer mammaire : Influence des adipocytes sur le processus d'angiogénèse et la moindre réponse thérapeutique / Influence of adypocyte secretions on angiogenic process and lesser therapeutic response

Bougaret, Lauriane 16 September 2015 (has links)
L'obésité, en constance augmentation, est un facteur de risque établi de cancer mammaire chez les femmes en post-ménopause associé à un mauvais pronostic favorisant la survenue de métastases et la moindre réponse thérapeutique chez ces patientes. Parmi les différentes hypothèses émises expliquant ce lien entre obésité et cancer, plusieurs arguments bibliographiques suggèrent une implication des sécrétions adipocytaires, dont les concentrations plasmiques sont modulées en situation d'obésité, dans la tumorogenèse mammaire. Les objectifs de ce travail étaient d'analyser le rôle des sécrétions adipocytaires, reflétant une situation d'obésité, dans le processus d'angiogenèse ainsi que dans la moindre réponse thérapeuthique aux traitements anti-cancéreux, notamment d'hormonothérapie.(...)Nos résultats suggèrent que les sécrétions adipocytaires sont impliquées dans la régulation de la tumorogenèse mammaire ce qui ouvre des perspectives préventives et/ou thérapeutiques prometteuses, ciblant les adipokines, pour les femmes en surpoids particulièrement à risque. / Obesity, constantly incrasing, is an established risk factor for breast cancer in post-menopausal women associed with a pour prognosis favoring the occurence of metastases and lower therapeutic response in these patient. Among the various hypotheses explaining the link between obesity and breast cancer, multiple bibliographic arguments suggest the involvement of adipocyte secretions, whose plasma concentrations are modulated in case of obesity, in mammary tumorogenesis. The objectives of thesis were to highlight the implication of adipocyte secretions, in a context of obesity, in the angiogenic process and therapeutic response to hormonal cancer traetments. (...) Adipocyte secretions are involved in the regulation of mammary tumorigenesis which opens up promising preventive or therapeutic perspectives targeting adipokines in situation of overweight.

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