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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.
41

Development of new methodologies in organic synthesis for the preparation of bioactive molecules / Développement de nouvelles méthodologies en synthèse organique pour la préparation de molécules bioactives

Hussein, Marwa 20 March 2017 (has links)
La thèse est divisée en trois chapitres indépendants. Chimie du β-lactames : Synthèse d'α-éthylène et d'α-alkylidène-β-lactames en utilisant la réaction de Kinugasa. Chimie de l'acylsilane : application d'une réaction aldolique intramoléculaire asymétrique sur un dérivé d'acylsilane nouvellement synthétisé. - Chimie médicinale: synthèse de nouvelles molécules à but anticancéreux.Dans le premier chapitre la réaction de Kinugasa a été appliquée pour la première fois à des alcynes vrais, portant en position propargylique un groupe partant permettait d'accéder directement et en une étape aux méthylène- et alkylidene β-lactames recherchés. Dans le second chapitre, la synthèse de molécules originales possédant à la fois une fonction acylsilane et un aldéhyde en position éloignée, et l'aldolisation intramoléculaire asymétrique a été explorée. Dans le dernier chapitre, notre objectif était de restaurer les propriétés apoptotiques au sein des cellules cancéreuses afin d'obtenir de nouveaux composés à activité antitumorale. A partir de données obtenues par modélisation moléculaire, nous avons fait le design de plusieurs séries d'analogues d'un inhibiteur connu(MIM-1) de la protéine anti-apoptotique Mcl-1. Huit composés ont été synthétisés et testés pour trois types de cellules cancéreuses (sein, ovaire et le mélanome). / The thesis is divided into three chapters:- β-lactams chemistry: synthesis of α-methylene and α-alkylidene-β-lactams using the Kinugasa reaction.- Acylsilane chemistry : applying asymmetric intramolecular aldol reaction on a newly synthesized acylsilane derivatives. - Medicinal chemistry: synthesis of new molecules with anticancer aimes. In the first chapter, Kinugasa reaction was applied for the first time with an alkyne bearing a nucleofuge in propargylic position that allowed us to discover a way of synthesis of exoalkylidene β-lactams. In the second chapter, a new acylislane derivatives bearing an aldehyde functional group in a remote position of the molecule were prepared, and asymmetric intramolecular aldolization reaction was performed. In the last chapter, our goal was to reinduce the pro-apoptotic properties in cancer cells in order to obtain new antitumor compounds. Starting from data obtained through molecular modeling studies, we designed and prepared several series of analogs for a known inhibitor (MIM-1) of the anti-apoptotic protein Mcl-1. Eight compounds have been synthetized and screened towards three types of cancer cells (breast, ovarian and melanoma).
42

Premières pharmacomodulations de la meiogynine A, un sesquiterpène dimère inhibiteur de l’interaction Bcl-xL/Bak, régulant l’apoptose / First pharmacomodulations of meiogynin A, an inhibitor of the Bcl-xL/Bak interaction which controls the apoptosis

Dardenne, Jérémy 15 November 2012 (has links)
La régulation de l’apoptose fait partie des nouvelles cibles thérapeutiques dans la lutte contre le cancer. L’apoptose est l’autodestruction programmée des cellules qui, suite à un besoin physiologique, permet de réguler le développement des cellules. Dans de nombreux cancers, ce mécanisme est inhibé par une surexpression des protéines anti-apoptotiques de la famille Bcl-2 comme Bcl-xL et Mcl-1. Ce phénomène entraîne le développement des cellules tumorales et des résistances aux chimiothérapies. Dans cette optique, notre équipe à l’Institut de Chimie des Substances Naturelles a développé un criblage de plantes tropicales sur ces cibles. Des écorces d’une annonacée de Malaisie, Meiogyne Cylindrocarpa, a été isolé un sesquiterpène dimère, la meiogynine A, présentant une bonne affinité vis-à-vis de Bcl-xL (Ki = 10.7 M). Sa synthèse totale a été réalisée au laboratoire afin de déterminer sa configuration absolue et d’étudier les premières relations structure activité. Un de ses diastéréoisomères a également présenté une bonne affinité vis-à-vis de la protéine Bcl-xL.Afin d’étudier et d’approfondir les premières relations structure activité, la modulation de la meiogynine A a été réalisée. La synthèse des diénophiles acides a été optimisée afin de conduire majoritairement aux diénophiles précurseurs des composés actifs. Différents triènes ont également été synthétisés au laboratoire en vue de modifier la partie Sud de la meiogynine A. Plusieurs analogues ont ainsi pu être obtenus et ont été évalués biologiquement sur des tests in vitro et ex vivo. Des études de modélisation moléculaire et de RMN structurale ont également été réalisées. / The control of the apoptosis is one of the new modern key to fight against the cancer. The apoptosis is the self destruction of cells, part of the homeostasis, which regulates the cell developement. In several cancers, the over-expression of anti-apoptotic proteins, as Bcl-xL and Mcl-1 parts of the Bcl-2 proteins family, inhibate this naturel process. This phenomenum induce the tumoral cells developement and the chemotherapy’s resistance. In order to find new compounds which can regulate the apoptosis, our group in the Institut de Chimie des Substances Naturelles has screened different tropical plants on these targets. A Malaysian plant, Meiogynine Cylindrocarpa, was selected and the phyotchemist work on this plant gave us a new sesquiterpen , the meiogynin A (Ki = 10.7 M on Bcl-xL). Its total synthesis was realised in our laboratory in order to determine its absolute configuration and find the first structure activity relation. One of the synthetised diastereoisomers has presented a better affinity toward the protein. In order to precise these first structure activity relations, the modulation of the meiogynin A was initiated. The synthesis of the acid dienophiles was optimised, the main compounds are the precursors of the active decalins. New triene was also obtained in order to modulate the South Part of the meiogynin A. Thanks to a Diels-Alder reaction, these precursors were combined in order to form new analogues of the meiogynin A. All these compounds were biologically tested (in vitro et ex vivo). Experiments of molecular docking and 2D NMR were also realised.
43

Recherche d'inhibiteurs naturels des protéines anti-apoptotiques Bcl-xL et Mcl-1 / Search for natural inhibitors of the anti-apoptotic proteins Bcl-xL and Mcl-1

Geny, Charlotte 24 October 2014 (has links)
Dans le but de rechercher des inhibiteurs naturels des protéines anti-Apoptotiques Bcl-XL et Mcl-1, deux essais biologiques ont été mis au point sur Bcl-XL/Bak-CF et Mcl-1/Bid-CF. Ces deux tests utilisent la polarisation de fluorescence et sont basés sur la liaison d’un peptide pro-Apoptotique marqué à la fluorescéine (Bak-CF ou Bid-CF) avec une protéine anti-Apoptotique (Bcl-XL ou Mcl-1). Au total, près de 600 extraits de pantes, provenant de diverses régions du monde, ont été criblés sur les deux protéines Bcl-XL et Mcl-1 permettant de sélectionner les extraits acétate d’éthyle des écorces de Knema hookeriana (Myristicaceae) et de Fissistigma latifolium (Annonaceae). L’analyse chimique des constituants des écorces de K. hookeriana a conduit à l’isolement de 12 lipides phénoliques dont 6 n’avaient jamais été isolés d’un organisme vivant. Seuls les acides anacardiques ont révélé de très fortes inhibitions de l’interaction Bcl-XL/Bak-CF et Mcl-1/Bid-CF dans les essais par polarisation de fluorescence. Une étude plus approfondie des interactions entre le plus actif des produits et les protéines (Bcl-XL, Mcl-1, Bak et Bid) par RMN, a montré que la modulation des interactions Bcl-XL/Bak et Mcl-1/Bid n’est pas liée à l’affinité de l’acide anacardique pour les protéines Bcl-XL et Mcl-1 mais a une forte affinité pour les peptides Bid et Bak. Le fractionnement bioguidé de l’extrait AcOEt des écorces de F. latifolium a conduit à l’isolement d’une nouvelle chalcone prénylée, la (±)-Écarlottone possédant une dual activité sur les protéines, Bcl-XL et Mcl-1. Par la suite, le fractionnement "RMN-Guidé" a mené à l’isolement de 6 analogues. / In order to search for natural inhibitors of anti-Apoptotic protein Bcl-XL and Mcl-1, two bioassays were developed on Bcl-XL/Bak-CF and Mcl-1/Bid-CF. Both assays use fluorescent polarisation, and are based on binding of a fluorescein labeled pro-Apoptotic peptide (Bak-CF or-CF Bid) with an anti-Apoptotic protein (Bcl-XL or Mcl-1). Nearly 600 extracts from various parts of the world were screened on both Bcl-XL and Mcl-1 proteins to select the ethyl acetate bark extracts of Knema hookeriana (Myristicaceae) and Fissistigma latifolium (Annonaceae). The chemical analysis of the constituents of K. hookeriana has led to the isolation of 12 phenolic lipids. 6 of them were never isolated from a living organism. Only anacardic acids showed very strong inhibition of the interaction Bcl-XL/Bak-CF and Mcl-1/Bid-CF in fluorescent polarisation assays. Further study of the interactions between the most active anacardic acid and proteins (Bcl-XL, Mcl-1, Bak and Bid) by NMR showed that the modulation of Bcl-XL/Bak and Mcl-1/Bid is not related to the affinity of the compoun to the anti-Apoptotic proteins, Bcl-XL and Mcl-1 but to its affinity for peptides, Bid and Bak. The bioguided fractionation of the AcOEt bark extract of F. latifolium led to the isolation of a novel prenylated chalcone, (±)-Écarlottone having a dual activity on protein, Bcl-XL and Mcl-1. Subsequently, fractionation "NMR-Guided" led to the isolation of 6 new analogs.
44

Unmasking Oncogene Addiction to the Epidermal Growth Factor Receptor in Triple Negative Breast Cancer: a Lesson in Intrinsic Resistance

Cruz-Gordillo, Peter G. 24 August 2020 (has links)
The rationale behind targeted molecular therapy in cancer, oncogene addiction, is that tumors rely on driver oncogenes to control their proliferation and survival. Therefore, an efficacious targeted therapy should induce a dual, detrimental response to the tumor. While there have been clinical success stories using targeted therapies, even tumors that are initially sensitive invariably develop resistance. In the case of triple negative breast cancer (TNBC), despite extensive evidence pointing to its driver oncogene status, inhibitors of the Epidermal Growth Factor Receptor (EGFR) are considered clinically inefficacious. Resistance to EGFR inhibition has been predominantly described as due to genetic alterations. Yet it remains unclear why patients exhibiting the same dysregulated status of a driver oncogene react to targeted therapy, as in the case of EGFR-mutant non-small cell lung cancer, while others do not at all (i.e., TNBC). Furthermore, not all of resistance can be described by genetic alterations to EGFR, to its pathway effectors, or to compensatory pathways. Emerging data reveals that drugs can induce resistance by rewiring epigenomic, transcriptional, and translational regulatory mechanisms. Unfortunately, a major limitation in designing efficacious treatments is our inability to predict whether cell types can rewire in response to drug exposure. Therefore, it is necessary to elucidate mechanisms of growth and survival in cells that have undergone rewiring. This study characterized intrinsic resistance to EGFR inhibition in TNBC. We found that EGFR inhibition induces rewiring, which results in a resistant growth state that bypasses the EGFR-MAPK pathway as a whole. Additionally, we found that a tRNA-modifying complex masks the oncogene addiction status of EGFR in TNBC by stabilizing the protein abundance of a pro-survival protein. Importantly, this happens solely in the context of EGFR inhibition. Taken together, this study highlights potential therapeutic strategies for TNBC and strategies that can be used to improve our understanding of targeted therapy resistance, especially intrinsic resistance.
45

蛋白激酶 CK2 與轉錄因子 SRF 所調控之抗細胞凋亡蛋白 Mcl-1 對 PC12 神經細胞之保護機制的探討 / Anti-apoptotic effects of Mcl-1 through CK2-mediated SRF pathway in PC12 cells

曾惠敏, Tseng, Hui Min Unknown Date (has links)
蛋白質激酶 CK2 是一種多功能的絲胺酸/蘇胺酸蛋白激酶,且普遍存在於哺乳類動物細胞中,CK2 受質眾多,對於細胞週期的發展、轉錄作用以及抗細胞凋亡等過程中扮演很重要的角色。SRF 是一種哺乳類動物的轉錄因子,它會結合到血清反應元素 SRE 上進而調控一些促進細胞存活的基因轉錄作用。Mcl-1歸類於抗細胞凋亡 Bcl-2 家族,具有促進細胞存活的能力。過去研究顯示 SRF 的 DNA 結合活性會受到蛋白激酶 CK2 的磷酸化而增加,且 SRF 對 Mcl-1 的活性調控作用也被描述在其他的研究中,然而,對於細胞的訊息目前還沒有更詳細的研究。在本實驗中,我們探討是否可以藉由 CK2 調控 SRF 的路徑來影響 Mcl-1 的表現以作為抗細胞凋亡的機制。利用 CK2 抑制劑 TBB 處理的結果顯示,在 4 hr 後,phospho-SRF 蛋白質表現的降低具有劑量相關性。而相似的降低也可以從 Mcl-1 的 mRNA 和蛋白質表現量觀察到。處理 24 hr 後,phospho-SRF 的蛋白質表現量有顯著降低,而 Mcl-1 的 mRNA 表現量相較 Mcl-1 的蛋白質影響層面微弱。另一方面,轉染野生型 CK2α 會增加 phospho-SRF,相反的,轉染抑制催化活性的突變型 CK2αA156 則會顯著降低 phospho-SRF 的表現。更進一步,野生型 CK2α 同時增加 Mcl-1 的 mRNA 及蛋白質層級,而 CK2αA156 則會降低 Mcl-1 的表現。突變型的 SRF99A 轉染作用降低 Mcl-1 的 mRNA 及蛋白質,並經由共同轉染的實驗顯示具有抵抗上游野生型CK2α 對 Mcl-1 蛋白質的影響。綜合這些結果我們認為 CK2α對 SRF 的訊息調控影響包括對 Mcl-1 的表現。且這條訊息路徑所促進的 Mcl-1 蛋白質表現可能對魚藤酮處理所引發的細胞凋亡作用具有保護的效果。 / Protein kinase CK2 is a multifunctional serine/threonine protein kinase with many protein substrates and is ubiquitously expressed in mammalian cells to play an important role in cell cycle progression, transcription, and anti-apoptosis. The serum response factor (SRF) is a mammalian transcription factor which binds to serum response element (SRE) and mediates some gene transcriptions relevent to promote the cell survival. The Myeloid cell leukemia 1 (Mcl-1) belongs to the anti-apoptotic Bcl-2 family and its effect are involved in promoting cell viability. Previous studies have revealed that the DNA-binding activity of SRF is enhanced when it is phosphorylated by protein kinase CK2. The activation regulation of Mcl-1 by SRF has also been reported in other studies. However, the detailed cellular signaling has not been studied well. In the present study, we investigate whether the regulation of Mcl-1 expression through CK2-mediated SRF pathway is involved in its anti-apoptotic effects. The results from CK2 inhibitor TBB revealed that the phosphorylated SRF were reduced in a dose-dependent manner after 4 hr of TBB treatments in PC12 cells. The similar decreases were also observed in the mRNA and protein levels of Mcl-1. After a 24 hr exposure of PC12 cells to TBB, a decreased in phosphorylated SRF and Mcl-1 mRNA were observed; a decreased in Mcl-1 protein level was also detected, albeit to a lesser extent. On the other hand, transfection of the wildtype CK2α increased, whereas transfection of the catalytically inactive CK2αA156 mutant decreased phosphorylated SRF. Further, wildtype CK2α increased, whereas CK2αA156 mutant decreased the mRNA and protein levels of Mcl-1. Furthermore, the mutant SRF99A transfection decreased, the mRNA and protein levels of Mcl-1 and antagonized the up-regulatory effects of wildtype CK2α on Mcl-1 protein level in the co-transfection experiments. These results together suggest that CK2α-mediated SRF signaling is involved in the regulation of Mcl-1 expression, and this signaling pathway may involves the anti-apoptotic effects of Mcl-1 against rotenone treatment.

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