La prise en charge du cancer reste dépendante de l’utilisation des agents cytotoxiques, avec les analogues nucléosidiques. Au-delà de leur similarité structurelle, certains de ces composés partagent une voie métabolique commune, où la cytidine déaminase apparaît comme enzyme majeure. L’existence d’une variabilité génétique et/ou phénotypique de la CDA nous a mené à nous intéresser aux relations entre le statut CDA et l’issue clinique des patients afin de déterminer si la CDA pouvait être considérée comme biomarqueur d’issue clinique chez les patients.Nos travaux personnels ont consisté à évaluer deux techniques permettant de mesurer l’activité de la CDA. Nous avons publié le premier cas mondial de toxicités mortelles sous azacytidine chez un patient CDA-déficient, ainsi que le premier cas de déficience en CDA et de toxicités sous cytarabine causées par la présence d’une variation génétique du gène CDA chez une patiente transplantée hépatique. L’influence du statut CDA a également été étudiée chez deux patients traités par azacytidine. Concernant la gemcitabine, nous avons démontré l’impact délétère en terme d’efficacité de l’augmentation de l’activité CDA chez les patients, ainsi que les résultats d’une étude multicentrique prospective dont le but était de déterminer si la CDA pouvait être un marqueur prédictif de l’apparition des toxicités sous gemcitabine, avec une étude pharmacocinétique en support. Les travaux préliminaires du pyroséquençage partiel de la CDA sur technologie Roche® sont présentés. L’ensemble de ces travaux de thèse confirme l’intérêt d’évaluer le statut CDA chez les patients susceptibles de recevoir une thérapie à base d’analogues nucléosidiques. / Nowadays, the management of cancer pathology remains largely dependent on the use of cytotoxic agents, including nucleoside analogs, used in a variety of settings. Beyond their structural similarity, some of these compounds also share a common metabolic pathway, wherein the cytidine deaminase (CDA) plays a pivotal role. The existence of constitutional genetic and / or phenotypic variability in CDA prompted us to study the relationships between the CDA status and clinical outcome in patients, and to determine if the constitutional CDA could be considered as a biomarker of efficacy and toxicity in patients treated with this class of drugs.Our personal work first consisted in evaluating two methods to measure the CDA enzymatic activity, in terms of robustness and cost. Then we published the first case-report of life-threatening toxicities in a CDA-deficient patient treated with azacytidine, and the first case of CDA deficiency and cytarabine-caused toxicities correlated with presence of a genetic variation in CDA gene in a liver-transplant patient. The influence of CDA status was also assessed in two patients treated with azacytidine. Regarding gemcitabine, we present the impact of an increase in CDA activity on loss of efficacy in patients, and the results of a prospective multicenter study whose purpose was to determine whether the CDA could be a predictive marker of the occurrence of gemcitabine-toxicities, with a pharmacokinetic study support. Finally, preliminary data on partial Roche®-pyrosequencing of CDA, also presented.All these thesis work confirms the interest to evaluate the CDA status in patients likely to receive a nucleosidic analogues-based therapy.

First part of this thesis was focused on the previously overlooked field of C1'-branched acyclic nucleoside phosphonates (ANPs). Five diverse synthetic approaches were developed/optimized affording key 6-chloropurine intermediates bearing N9 -phosphonomethoxyethyl (PME) branched at C1' position in 2-4 steps. It was demonstrated that these intermediates can be further vastly diversified into ANPs bearing both natural and unnatural nucleobases. Single enantiomers as well as racemates of final C1'-branched ANPs (overall 48 final compounds) were prepared and selected compounds were evaluated with respect to their biological properties. The aforementioned ANPs showed no antiviral potency against studied viruses and only weak to moderate cytostatic activity. Adenine C1'-branched ANPs proved to be the most potent currently known inhibitors of Trypanosoma brucei adenine phosphoribosyl transferase (TbrAPRT), an enzyme involved in purine salvage pathway (PSP) of T. brucei. Further biological evaluation of prepared compounds is in progress. Second part of this thesis was focused on development of novel prodrug moieties with higher selectivity index (i.e. toxicity/potency ratio - SI) based on so-called ProTide prodrugs where phenol (present in ProTides) was replaced by tyrosine derivatives. Tenofovir was...

This thesis deals with the preparation of acyclic nucleosides and nucleoside phosphonates of compounds T-705 (6-fluoro-3-hydroxypyrazine-2-carboxamide) and T-1105 (3-hydroxypyrazine-2-carboxamide). Acyclic nucleoside phosphonates are substances that can terminate viral RNA or DNA replication, and some of them are used in the treatment of viral diseases. T-705 and T-1105 have shown activity against the influenza virus, and T-705 has already been approved for its treatment in Japan. Since both compounds mimic natural nucleobases in the body, their acyclic nucleosides and nucleoside phosphonates also have the potential to be biologically active. Methods for the synthesis of 3-fluoro-2-(phosphonomethoxy)propyl and 3-hydroxy-2-(phosphonomethoxy)propyl derivatives of T-705 and T-1105, their prodrugs containing lipophilic groups for the improvement of the pharmacokinetic properties and also their phosphonate diphosphates, suitable for the biological activity measurements, have been proposed. Some of these derivatives were subsequently prepared. Key words: acyclic nucleosides, acyclic nucleoside phosphonates, T-705, T-1105, favipiravir, antiviral activity, influenza

PMEG [9-(2-phosphonomethoxyethyl)guanine] and PMEDAP [9-phosphonomethoxy- ethyl)-2,6-diaminopurine] are acyclic nucleoside phosphonates possessing cytotoxic properties. Antiproliferative effect of PMEG was demonstrated in various tumor cell lines in vitro. PMEG also represents an active component of some experimental prodrugs with enhanced selectivity and efficacy (such as GS-9219). PMEDAP seems to have weaker effect in vitro compared to PMEG, however it exhibited pronounced antitumor effect in SD-rats with spontaneous lymphoma. Therefore it was included in the present study as well. The aim of this study was to describe the interactions of PMEG and PMEDAP with p38 MAP kinase signaling and its relationship to the apoptosis. We investigated the influence of these compounds on the expression of four genes encoding p38 MAPK isoforms and whether this change is translated into the protein. It was found that PMEG up-regulates p38β and γ mRNA in CCRF-CEM cells and p38 β and δ in HL-60 cells. The effect of PMEDAP was less pronounced than that of PMEG. However, total p38 protein level remained unaffected by PMEG and PMEDAP. Activation of p38 MAPK cascade was also measured in the cells exposed to these agents using phospho-specific antibodies. We found that neither PMEG nor PMEDAP activated p38 kinase...

Deutsch: Die vorliegende Arbeit beinhaltet die kombinatorische Synthese sowie biomedizinische Aspekte von neuen, lipophilisierten Nucleosiden (Nucleolipiden) als small molecules. Für die Synthesen wurden sowohl Nucleosid-Metabolite als auch -Antimetabolite lipophilisiert. Als Lipidreste wurden natürlich vorkommende Verbindungen, wie azyklische Terpene und (a)symmetrische Ketone verwendet. Diese wurden am O-2‘,3‘-cis-glycosidischen Rest oder an der N(3)-Position von β-D-Pyrimidinen oder an der N(1)-Position von β-D-Purinen eingeführt. Die Einführung der Reste erfolgte durch Ketalisierung der glyconischen Hydroxylgruppen oder durch direkte Alkylierung sowie durch Dimroth-Umlagerung des Aglycons. Zusätzlich wurden in weiteren Reaktionen ausgewählte Nucleolipide in 2-(Cyanoethyl)phosphoramidit für die automatische DNA-Festphasensynthese von Oligo-nucleotiden umgewandelt. Diese wurden für eine Reihe von Penetrationsversuchen hinsichtlich ihres Einlagerungs-und Penetrationsverhaltens in eine künstliche Lipidmembran untersucht und untereinander verglichen. Die synthetisierten Nucleolipide wurden NMR-spektroskopisch im Hinblick auf die strukturellen Parameter (1) Zuckerpucker (3’T2‘⇌3’T2‘) und (2) die Konformation um die exozyklische C(4‘)-C(5‘)-Bindung (γ+(g)⇌γt⇌γ-(g)) charakterisiert. Außerdem wurden die Nucleolipide hinsichtlich ihrer biologischen Aktivität in in vitro-Tests auf humane, differenzierte THP-1-Makrophagen bezüglich des Immunoeffekts und auf eine Rattengliom- sowie einer humanen Gliom-Zellline bezüglich der Antitumoraktivität getestet. English: The thesis comprises the combinatorial synthesis and biomedicinal aspects of novel lipophilized nucleosides (Nucleolipids) as small molecules. Nucleoside-metabolites, as well as -antimetabolites, were used for the lipophilization. The chemical structure of the lipid residues resembles naturally-occurring compounds, namely acyclic terpenes, and (a)symmetric ketones. They are positioned either at the O-2’,3’-cis-glyconic moiety or at the N(3) of β-D-pyrimidines or N(1) of β-D-purines. The introduction of the lipophilic residues was performed either by ketalization of the glyconic hydroxyls or by direct alkylation as well as by Dimroth rearrangement at the N-alkylated aglycone. Additionally, selected nucleolipids were further converted to 2-(cyanoethyl) phosphoramidites as building blocks for automated solid phase nucleic acid synthesis. The latters were used for the preparation of a series of lipo-oligonucleotides which were studied with respect to their immobilization within artificial lipid bilayers and compared concerning immobilization rate and stability. The resulting nucleolipids were characterized with respect to the structural parameters (1) the sugar pucker (3’T2‘⇌3’T2‘) as well as (2) the conformation around the exocyclic C(4’)-C(5’)-bond (γ+(g)⇌γt⇌γ-(g)) by 1H-NMR-spectroscopy. Moreover, the biological activity of the nucleolipids was tested in-vitro on human, differentiated THP-1-macrophages for the immunoeffect and towards the rat gliom cell line BT4Ca as well as a human gliom (GOS-3) for anticancer activity.

Several lipopeptidyl nucleoside antibiotics that inhibit bacterial translocase I (MraY) involved in peptidoglycan cell wall biosynthesis contain an aminoribosyl moiety, an unusual sugar appendage in natural products. A-90289 and muraminomicin are the two representative antibiotics that belong to this family. Bioinformatic analysis of the biosynthetic A-90289 gene clusters revealed that five enzymes are likely involved in the assembly and attachment of the aminoribosyl unit. These enzymes of A-90289 are functionally assigned by in vitro characterization. The results reveal a unique ribosylation pathway that highlighted by uridine-5′-monophosphate as the source of the sugar, a phosphorylase strategy to generate a sugar-1-phosphate, and a primary amine-requiring nucleotidylyltransferase that generates the NDP-sugar donor. Muraminomicin, which has a structure similar to A-90289, holds the distinction in that both ribose units are 2-deoxy sugars. The biosynthetic gene cluster of muraminomicin has been identified, cloned and sequenced, and bioinformatic analysis revealed a minimum of 24 open reading frames putatively involved in the biosynthesis, resistance, and regulation of muraminomicin. Similar to the A-90289 pathway, fives enzymes are still likely involved in the assembly of the 2,5-dideoxy-5-aminoribose saccharide unit, and two are now functionally assigned and characterized: Mra20, a 5′-amino-2′,5′-dideoxyuridine phosphorylase and Mra23, a UTP:5-amino-2,5-dideoxy-α-D-ribose-1-phosphate uridylyltransferase. The cumulative results are consistent with the incorporation of the ribosyl appendage of muraminomicin via the archetypical sugar biosynthetic pathway that parallels A-90289 biosynthesis

The use of a surface plasmon biosensor fills a missing link in kinetic studies of enzymes, since it measures directly the interaction between biomolecules and allows determination of parameters that are determined only indirectly in activity assays. The present thesis deals with kinetic and dynamic aspects of ligand binding to two viral enzymes: the human cytomegalovirus (HCMV) protease and the human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). The improved description of interactions presented herein will contribute to the discovery and development of antiviral drugs. The biosensor method provided new insights into the interaction between serine proteases and a peptide substrate, as well as substrate-induced conformational changes of the enzymes. The direct binding assay served as a tool for characterising the binding mechanism of HCMV protease inhibitors. Kinetic details of the interaction between HIV-1 RT and non-nucleoside reverse transcriptase inhibitors (NNRTIs) were unravelled. The recorded sensorgrams revealed several forms of complexity. A general binding model for the analysis was derived from the data, describing a two-state mechanism for the enzyme and a high- and a low-affinity interaction with the inhibitor. Interaction kinetic constants were determined for the clinically used NNRTIs and several investigational inhibitors. The established method was applied to investigate the mechanism of resistance against NNRTIs. Amino acid substitutions in the NNRTI-binding site resulted in both decreased association rates and increased dissociation rates for the inhibitors. The K103N and the L100I substitution also interfered with the formation of the binding site, thereby facilitating inhibitor binding and unbinding. Finally, thermodynamic analysis revealed that, despite the hydrophobic character of the interaction, NNRTI binding was mainly enthalpy-driven at equilibrium. Large entropy contributions in the association and dissociation indicated that binding is associated with a dynamic effect in the enzyme.

Les peroxyrédoxines (PRXs) forment une famille de peroxydases communes à tous les organismes vivants et ubiquitaires dans la cellule. Leur particularité provient d’un ou deux résidus cystéines accomplissant un cycle d’oxydo-réduction à l’aide d’un donneur d’électron. Ces protéines thiols sensibles au potentiel redox sont impliquées dans le mécanisme de détoxification du H2O2, une molécule oxydante induite lors de situations de stress. Les PRXs pourraient être induites par le stress et régulées par phosphorylation. En effet, des expérimentations in vitro ont démontré que la nucléoside diphosphate kinase 1 (NDPK1) a la capacité de phosphoryler une PRX cytosolique de pomme de terre. Ce mémoire décrit les travaux expérimentaux effectués pour caractériser la fonction de la PRX. Pour cela, le clonage d’une isoforme a été effectué, suivi d’une caractérisation biochimique et d’une étude d’expression de la protéine. Les données de séquençage révèlent qu’il s’agit d’une PRX de type II phylogénétiquement liée aux PRXs cytosoliques. L’ADNc codant pour cette peroxyrédoxine (PRX1) a été cloné chez Solanum chacoense. Une protéine recombinante portant une étiquette (6xHis) en N-terminale a été produite. Des essais enzymatiques ont confirmé la fonction antioxydante de la protéine recombinante et un anticorps polyclonal a été généré chez le lapin puis utilisé en conjonction avec un anticorps anti-NDPK1 pour déterminer les patrons d’expression généraux de ces protéines chez Solanum lycopersicum et Solanum tuberosum lors de situations de stress. Les données démontrent que les deux protéines sont généralement co-exprimées mais pas co-régulées et que la PRX1 est induite en certaines situations de stress. / The peroxiredoxins (PRXs) are a recently discovered family of peroxidases found in all organisms and ubiquitous in the cell. An important particularity of these proteins is the presence of one or two active cysteines that accomplish an oxydo-reduction cycle with an electron donor. The PRXs are sensitive to the redox potential and are implicated in the detoxification of the H2O2, an oxidante molecule induced in stress situations. The PRXs should be induced in stress situations and regulated by phosphorylation. Indeed, in vitro experimentations have shown that the NDPK1 can phosphorylate a cytosolic PRX isoform of the potato. This dissertation describes the experimentation made to acquire a preliminary understanding of the function of the PRX. For this purpose, we cloned a PRX isoform, followed by a biochemical characterization and expression studies of the protein. The sequencing data shown a type II PRX phylogenetically related to the cytosolic isoforms. The cDNA of this peroxiredoxin (PRX1) has been cloned in Solanum chacoense. The recombinant protein produced had a N-terminal (6xHis) tag. Enzymatic assays confirmed the antioxidant activity of the recombinant protein and a polyclonal antibody has been generated from the rabbit. This antibody was used in conjunction with an antibody anti-NDPK1 to determine the general expression patterns of those proteins during stresses in Solanum lycopersicum and Solanum tuberosum. The results obtained showed that the two proteins are generally co-expressed but not co-regulated. Obvious experimental facts displayed an induction of the PRX1 in biotic and abiotic stresses situations.

Foram determinadas por meio de difração de raios x as estruturas de cinco compostos azaçúcares. Foram estudadas as interações envolvidas na formação das redes cristalinas em cada um dos compostos analisados. Foi encontrado que nos compostos azaçúcares estudados, as interações principais são as ligações de hidrogênio do tipo C-H···O e C-H···π. Este comportamento foi verificado usando ferramentas como as superfícies de Hirshfeld e os gráficos de impressão digital. Realizou-se o estudo de docking molecular dos compostos azaçúcares com respeito à enzima purina nucleosídeo fosforilase (PNP). Foi determinado que estes compostos têm a capacidade de entrar no sitio ativo da PNP. O estudo das interações dos cinco azaçúcares com a PNP mostrou que estes compostos apresentam as mesmas interações presentes em inibidores da PNP já reportados. / Structures of five azasugars were determined by X-ray diffraction. Crystal network interactions were analyzed for each compound. The main interaction found for these azasugar compounds is hydrogen bond as C-H···O e C-H···π. This behavior was verified by tools as Hirshfeld surface and 2D finger print plots. Molecular docking was performed for azasugar compounds in Purine Nucleoside phosphorylase (PNP). This study confirmed that these compounds are available to enter to the PNP active site. Interactions exploration showed the same interactions for the azasugars studied and for already known PNP inhibitors.

No description available.