Le MTX est un agent anticancéreux utilisé à hautes doses pour le traitement des hémopathies malignes et de certaines tumeurs solides. Il présente une importante variabilité pharmacocinétique (PK) traduite par des surexpositions à l'origine de toxicités très sévères, surtout lors d'une administration à haute dose. Les retards d'élimination du MTX surviennent encore de manière inattendue et il n'existe à ce jour aucun biomarqueur qui permette un diagnostic précoce du risque de surexposition. Nos travaux ont focalisé sur les déterminants de l'élimination rénale du MTX, et en particulier le rôle du transporteur MRP2/ABCC2 dans ce processus. Ce travail s'inscrit donc (1) dans la recherche de biomarqueurs métabolomiques urinaires prédictifs de la PK du MTX et (2) dans l'identification de substrats endogènes de MRP2 parmi un panel de 217 acides organiques urinaires analysés par chromatographie gazeuse couplée à la spectrométrie de masse. Nos analyses ont abouti à un profil de 28 anions organiques endogènes, prédictifs de la CL MTX. L'outil était en revanche mal adapté à la prédiction des retards d'élimination. Pour la 2eme partie, nos résultats tendent à montrer que 8 métabolites urinaires sont des bio-marqueurs potentiels de l'activité de MRP2. Leur utilisation en clinique nécessite encore des études confirmatoires. / MTX is an anticancer agent used at high doses for the treatment of malignant haemopathies and some solid tumors. It presents an important pharmacokinetic variability (PK), manifested by overexposures causing very severe toxicities, especially when administered at high doses. Delayed elimination of MTX still occurs unexpectedly and there is currently no biomarker that allows early diagnosis of the risk of overexposure. Our work focused on the determinants of renal elimination of MTX, and particularly on the role of MRP2 / ABCC2 in this process. This work is therefore devoted to (1) the search for metabolomic biomarkers predictive of MTX PK and (2) the identification of endogenous substrates of MRP2, from a panel of 217 urinary organic acids analyzed by gas chromatography-mass spectrometry. Our analyses resulted in a profile of 28 endogenous organic anions, predictive of CL MTX. The tool was, on the other hand, poorly adapted to the prediction of delayed elimination. For the second part, our results tend to show that 8 urinary metabolites are potential biomarkers of MRP2 activity. Their clinical use still requires confirmatory studies.

L’obtention de la structure tridimensionnelle des protéines membranaires (PMs) est cruciale pour la chimie médicinale et la biochimie. Afin de maintenir les PMs en solution, et donc d’éviter leur agrégation, pour les études structurales et fonctionnelles, l’utilisation de détergents est indispensable. Cependant, la conformation des PMs en complexe avec les détergents pourrait être très différente de celle dans la membrane. Nous avons synthétisé une nouvelle famille de détergents, dans lesquels des carboxylates incorporés pourraient générer un réseau de ponts salins avec les acides aminés basiques des PMs, entraînant des interactions plus étroites qui pourraient préserver leur structure native. Les détergents dans lesquels la glycoconjugation a été réalisée par la réaction de cycloaddition d'azide-alkyne (CuAAC) catalysée par le Cu (I) ont montré une capacité remarquable à extraire, à stabiliser et à cristalliser les PMs étudiées. D'autre part, de nouveaux inhibiteurs efficaces d’ABCC2, une PM non cristallisée à ce jour, ont été identifiés par criblage : les 2-indolylméthylènebenzofuranones. De tels composés pourraient être considérés comme des outils pour étudier le rôle d’ABCC2 dans la pharmacocinétique des médicaments. / Understanding of tridimensional structure of membrane proteins (MPs) is crucial in medicinal chemistry and biochemistry. To maintain them in solution and consequently to prevent them from aggregation for structural and functional studies, utilization of detergents is indispensable. However, the conformation of MPs in complex with detergents could be very different from its membrane-embedded one. We synthetized new family of detergents, in which the incorporated carboxylates could generate a network of salt-bridges with basic-residue-enriched region of MPs, confer tighter interactions which could preserve their structural integrity. The detergents in which the glycoconjugation was achieved by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction showed remarkable capacity to extract, stabilize and crystallize studied PMs. On the other hand, novel inhibitors of ABCC2, a non-crystallized MP to date, were identified by screening: the 2-indolylmethylenebenzofuranones. Such compounds could be considered as useful tools to further investigate the role of ABCC2 in the pharmacokinetics of drugs.

Inherited hyperbilirubinemias are a group of metabolic disorders, characterized by increased levels of total serum bilirubin or its conjugated fraction. Most of these hyperbilirubinemias are inherited autosomal recessively and are manifested in young age. Increased bilirubin reflects the genetic disturbances in one of the enzymes of heme degradation pathway, the defect of bilirubin conjugation (UGT1A1 gene) or its transport (ABCC2, OATP1B1, OATP1B3). All of these proteins are involved not only in elimination of bilirubin, but various substrates; therefore the performed studies have a great pharmacogenomics impact. We have studied the molecular pathology of hereditary hyperbilirubinemias in Caucasian and Roma population and to compare the clinical and biochemical results with the molecular genetic data. We described the impact of compound defect of c.-3279T>G and g.175492_175493insTA on total serum bilirubin and calculated the linkage disequlibrium of these two variants in promoter region of UGT1A1 gene. We also verified, that the population distribution of both variants is in concordance with the literature. In our second study, we have described the rare conjugated hyperbilirubinemia Dubin-Johnson type among 7 Roma families. We have found a novel variant NG_011798.1:c.[1013_1014delTG] together with...

Inherited hyperbilirubinemias are a group of metabolic disorders, characterized by increased levels of total serum bilirubin or its conjugated fraction. Most of these hyperbilirubinemias are inherited autosomal recessively and are manifested in young age. Increased bilirubin reflects the genetic disturbances in one of the enzymes of heme degradation pathway, the defect of bilirubin conjugation (UGT1A1 gene) or its transport (ABCC2, OATP1B1, OATP1B3). All of these proteins are involved not only in elimination of bilirubin, but various substrates; therefore the performed studies have a great pharmacogenomics impact. We have studied the molecular pathology of hereditary hyperbilirubinemias in Caucasian and Roma population and to compare the clinical and biochemical results with the molecular genetic data. We described the impact of compound defect of c.-3279T>G and g.175492_175493insTA on total serum bilirubin and calculated the linkage disequlibrium of these two variants in promoter region of UGT1A1 gene. We also verified, that the population distribution of both variants is in concordance with the literature. In our second study, we have described the rare conjugated hyperbilirubinemia Dubin-Johnson type among 7 Roma families. We have found a novel variant NG_011798.1:c.[1013_1014delTG] together with...

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Submitted by CAROLINE PLACIDI DE BORTOLI null (carubortoli@yahoo.com.br) on 2018-02-22T10:06:56Z No. of bitstreams: 1 Tese_Caroline_Placidi_De_Bortoli.pdf: 20556112 bytes, checksum: 3c463875d34d1f0b87961046250a6dab (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-02-22T12:45:28Z (GMT) No. of bitstreams: 1 debortoli_cp_dr_jabo.pdf: 20556112 bytes, checksum: 3c463875d34d1f0b87961046250a6dab (MD5) / Made available in DSpace on 2018-02-22T12:45:28Z (GMT). No. of bitstreams: 1 debortoli_cp_dr_jabo.pdf: 20556112 bytes, checksum: 3c463875d34d1f0b87961046250a6dab (MD5) Previous issue date: 2018-02-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Plutella xylostella é uma praga de grande importância para as crucíferas em todo o mundo. Embora seja controlada com inseticidas sintéticos e biológicos, ela pode desenvolver resistência rapidamente a uma variedade de inseticidas. Os biopesticidas mais comuns utilizados para controlar P. xylostella são baseados na bactéria entomopatogênica Bacillus thuringiensis. Embora muitos estudos tenham sido realizados com Bt, o modo de ação ainda não é totalmente compreendido. Uma grande diversidade de genes é diferencialmente expressa no intestino médio de insetos resistentes, o que sugere que vários processos celulares podem estar envolvidos na resistência. Descobertas recentes mostraram que as mutações no gene que codifica o transportador ABCC2 são responsáveis pela resistência às toxinas Bt em diferentes espécies de insetos. O objetivo desta pesquisa foi testar a hipótese de que a susceptibilidade de P. xylostella a Bt se correlaciona com o nível de expressão dos componentes desse regulador de estresse. Os níveis de expressão dos genes ALP, APN, CDKAL 1, MAP4K4 e ABCC2 foi comparado utilizando qPCR, entre populações suscetíveis e resistentes de P. xylostella. A investigação da sequência de DNA do cDNA do ABCC2 foi realizada, por PCR e sequenciamento, para testar a hipótese de que a susceptibilidade de P. xylostella a Bt se correlaciona com mutações no gene ABCC2. Foram realizados retrocruzamentos entre populações suscetíveis e resistentes e cruzamentos de complementação entre populações resistentes. Nossa pesquisa demonstrou que não há padrões na expressão dos genes testados demonstrando nenhuma associação entre expressão e resistência/susceptibilidade. No entanto, ao investigar a sequência do gene ABCC2, encontrou-se uma mutação no gene da população brasileira resistente, que poderia ser responsável pela causa da resistência da população estudada neste trabalho. Os ensaios de retrocruzamentos não confirmaram que a resistência foi devida à supressão de 1 pb encontrada, no entanto, os ensaios complementares indicaram que a população brasileira compartilha um alelo de resistência com a população havaiana resistente. / Plutella xylostella is a major insect pest of cruciferous crops worldwide. Although controlled with both synthetic and biological insecticides it can rapidly evolve resistance to a variety of insecticides. The most common biopesticides used to control P. xylostella are based on the entomopathogenic bacterium Bacillus thuringiensis. Although many studies have been performed on Bt, the mode of action is still not fully understood. A wide diversity of genes are differentially expressed in the midgut of resistant insects, this suggests that a variety of cell processes may be involved in the preservation of resistance. Recent discoveries have shown that mutations in the gene encoding an ABCC2 transporter are responsible for resistance to Bt toxins in various different insect species. The aim of this research was to test the hypothesis that the susceptibility of P. xylostella to Bt correlates with the level of expression of components of this putative stress-response regulon. The level of expression of ALP, APN, CDKAL 1, MAP4K4 and ABCC2 genes were compared using qPCR, between susceptible and resistant P. xylostella populations. The investigation of the DNA sequence of ABCC2 cDNA was performed, through PCR and sequencing, to test the hypothesis that the susceptibility of P. xylostella to Bt correlates with mutations on the ABCC2 gene. Backcrosses between susceptible and resistant populations and complementation cross between resistant populations were performed. Our research demonstrated that there were no patterns in the expression of the genes tested demonstrating no association between expression and resistance/susceptibility. However, when investigating the ABCC2 gene sequence, a mutation in the gene of the Brazilian resistant population was found, which could be responsible for the resistance of the Brazilian population studied in this research. Backcrossing assays didn’t confirm that the resistance was due to the 1bp deletion found, however complementation assays indicated that the resistant Brazilian population shares a resistance allele with the resistant Hawaiian population. / FAPESP: 2015/05891-6 / FAPESP: 2016/04868-3 / CNPq: 140916/2014-8 / CNPq: 166510/2017-3

Tumorzellen können vielfältige Resistenzmechanismen gegenüber Zytostatika entwickeln. Untersuchungen an drei humanen Tumorzellinien und ihren cisplatinresistenten Varianten zeigten eine Assoziation von erhöhter MRP2-Expression und dem Auftreten von Cisplatinresistenz. Darüberhinaus waren die cisplatinresistenten Zellinien gegenüber Carboplatin kreuzresistent. Um weitere Faktoren im Zusammenhang mit der Cisplatinresistenz zu untersuchen, wurde der Mutationsstatus von p53 und der zelluläre Glutathiongehalt in den Zellinien bestimmt. Der offene Leserahmen von MRP2 aus der cisplatinresistenten Ovarialkarzinomzellinie A2780RCIS wurde für die Transfektion in die cisplatinsensitive Zellinie A2780 genutzt. Die Transfektanten zeigten eine Überexpression von MRP2 und wiesen eine Resistenz gegenüber Cisplatin und Carboplatin auf. Dies konnte in Zellzyklus- und Apoptose-Untersuchungen unter Cisplatinbehandlung gestätigt werden. Durch computergestützte Faltungsanalysen von Abschnitten der MRP2-mRNA wurden zwei potentielle Ribozymschnittstellen ausgewählt. Die konstruierten Anti-MRP2-Hammerhead-Ribozyme RzM1 und RzM2 wurden im zellfreien System auf ihre Schnittaktivität getestet und erwiesen sich als katalytisch aktiv. Es wurden verschiedene kinetische Parameter für RzM1 und RzM2 ermittelt und mit anderen Ribozymen verglichen. Die Ribozyme zeigten eine gute Effektivität bei der Spaltung ihres Zielmoleküls, wobei RzM1 die höhere Effektivität aufwies. Beide Ribozyme wurden auf ihre Wirksamkeit durch Transfektion in die Zellinie A2780RCIS getestet. Die untersuchten Transfektanten zeigten eine geringere Expression von MRP2 auf mRNA- und Proteinebene und wiesen eine verminderte Resistenz gegenüber Cisplatin, Carboplatin, Daunorubicin und Etoposid auf. Die Ribozyme RzM1 und RzM2 waren gleichermaßen für die Expressionsregulierung von MRP2 in Tumorzellen geeignet. In Zellzyklus- und Apoptose-Untersuchungen wurde funktionell bestätigt, daß die A2780RCIS-Anti-MRP2-Ribozym-Transfektanten auf eine Cisplatinbehandlung stärker ansprechen als die cisplatinresistente Ausgangszellinie A2780RCIS. Die Anwendung der Ribozyme RzM1 und RzM2 zur Unterstützung der Chemotherapie von Tumorzellen scheint daher vielversprechend. / Tumour cells can develop a lot of resistance mechanisms against cytostatic drugs. Examinations of three human tumour cell lines and their cisplatinresistant variants showed an association of elevated MRP2 expression and the occurrance of cisplatinresistance. Moreover, the cisplatinresistant cell lines were crossresistant against carboplatin. To examine further factors in context of cisplatinresistance the mutation status of p53 and the cellular glutathione content of the cell lines were determined. The MRP2-open reading frame of the cisplatinresistant ovarian carcinoma cell line A2780RCIS was used for transfection into the cisplatinsensitive cell line A2780. The transfectants showed an overexpression of MRP2 and a resistance against cisplatin and carboplatin. This could be confirmed with analysis of the cell cycle and apoptosis induction after treatment with cisplatin. Using computer aided folding analysis of MRP2 mRNA parts two possible ribozyme cleavage sites were selected. The constructed anti-MRP2 hammerhead ribozymes RzM1 and RzM2 were tested in a cell-free system with respect to their cleavage activities and were found to be catalytic active. Various kinetic parameters of RzM1 and RzM2 were determined and compared with other ribozymes. The ribozymes showed a good effectivity for the substrate cleavage, although RzM1 had the better effectivity. Both ribozymes were tested for their effectiveness after transfection into the cell line A2780RCIS. The transfectants showed a lower MRP2 expression on mRNA and protein level and also a reduced resistance against cisplatin, carboplatin, daunorubicin, and etoposide. The ribozymes RzM1 and RzM2 were both equally suitable for the regulation of MRP2 expression in tumour cells. Analysis of cell cycle and apoptosis induction could confirm functionally the higher sensitivity of the A2780RCIS-anti-MRP2 ribozyme transfectants after treatment with cisplatin in comparison to the cisplatinresistant cell line A2780RCIS. Therefore, the application of the ribozymes RzM1 and RzM2 for the support of cancer chemotherapy seems to be promising.

Tumorzellen entwickeln häufig Resistenzen gegen verschiedene strukturell und funktionell unabhängige Zytostatika, was als Multidrug-Resistenz (MDR) bezeichnet wird und die Hauptursache für das Scheitern einer Chemotherapie ist. Mit Hilfe von in vitro-Untersuchungen wurden erhöhte Genexpressionen der ABC-Transporter MDR1, MRP2 und BCRP als maßgebliche Resistenzfaktoren identifiziert, wie z.B. in den Magenkarzinomzellinien EPG85-257RDB (MDR1) und EPG85-257RNOV (BCRP) sowie in der Ovarialkarzinomzellinie A2780RCIS (MRP2). Ziel der Arbeit war die Entwicklung eines auf Ribozym-Technologie basierenden Therapieansatzes, welcher die Expressionen der oben genannten ABC-Transporter simultan inhibiert und dessen Anwendung zur Reversion der zellulären MDR führt. Dazu wurde ein Multitargetmultiribozym (MTMR) entwickelt, das aus in trans-aktiven Ribozymen besteht, die gegen die ABC-Transporter mRNAs gerichtet sind sowie aus in cis-spaltenden Ribozymen und aus Spacer-RNA-Sequenzen. Durch autokatalytische Spaltung in cis konnten die in trans-aktiven Ribozyme aus dem Gesamt-MTMR freigesetzt werden. Die Analyse der kinetischen Parameter des MTMRs ergab, daß die autokatalytisch entstandenen MTMR-Fragmente ihre Substrat-RNAs im Vergleich zu den korrespondierenden Monoribozymen ohne Einbuße an Effizienz spalten können. Darüber hinaus wurde die MTMR-Sequenz stabil in den drei eingangs genannten MDR-Zellinien exprimiert, was in einer signifikanten Reduktion der jeweiligen Ziel-mRNAs (97 % MDR1-, 80 % BCRP-, 96 % MRP2-mRNA) und der entsprechenden Proteine resultierte. Die Multidrug-Resistenz konnte aufgrund der MTMR-Expression um 70% (A2780RCIS), 95% (257RNOV), 100% (257RDB) und die Zytostatikumsakkumulation um 90% (257RNOV-Zellen) sowie 100% (257RDB-Zellen) revertiert werden. Das MTMR stellt erstmalig ein RNA-Konstrukt dar, welches in der Lage ist, simultan mehrere unabhängige Gene funktionell auszuschalten. Es besitzt daher ein großes Potential für zukünftige gentherapeutische Ansätze. / Cancer cells are often insensible against structurally and functionally unrelated drugs that is known as multiple drug resistance (MDR) and the main cause for treatment failure. Overexpression of the ABC-transporters P-gp (ABCB1), MRP2 (ABCC2), and BCRP (ABCG2) is associated with MDR in several cancer cell lines, e.g. in the stomach carcinoma cell lines EPG85-257RDB (P-gp), EPG85-257RNOV (BCRP), and in the ovarian carcinoma cell line A2780RCIS (MRP2). We aimed the development of a novel hammerhead ribozyme-based therapeutic approach capable of simultaneous silencing of the prementioned ABC-transporters, and consequently of reversing MDR phenotypes. We designed a so-called multitarget multiribozyme (MTMR) consisting of trans-acting hammerhead ribozymes directed against the MDR1, MRP2, and BCRP transcripts, of MDR1 homologous spacer sequences, and of cis-acting ribozymes against the spacer sequences. Autocatalytic cleavage in cis excised the full-length MTMR, and released trans-acting hammerhead ribozymes. We also evaluated the catalytic features of the MTMR using large RNA target molecules. Comparison of the kinetic values of the autocatalytically derived MTMR fragments with those of corresponding mono-ribozymes demonstrated an MTMR-mediated substrate cleavage without distinct loss in catalytic efficiency. Moreover, the MTMR was stably expressed in the prementioned multidrug-resistant cancer cell lines, and decreased the targeted transcripts about 97% (MDR1), 80% (MRP2), and 96% (BCRP) as well as the corresponding protein levels, respectively. Cellular MDR could be reverted about 70% (A2780RCIS), 95% (257RNOV), and 100% (257RDB). Additionally, the MTMR reversed mitoxantrone accumulation entirely, and daunorubicin accumulation about 90% in stomach carcinoma cells, respectively. Taken together, the MTMRs capability of simultaneous silencing of multiple genes provides an effective instrument to knockdown genes of interest.

Background: Negative outcomes from fetal exposure to maternal dug use include Neonatal Abstinence Syndrome (NAS) and altered development, the unpredictability of which suggests a biological element as yet not accounted for. The manner in which the human placenta protects the fetus from xenobiotics such as drugs of misuse is not completely characterised. However, Adenosine Triphosphate Binding Cassette (ABC) transporters in placentae have demonstrated their ability to efflux xenobiotics away from the fetal vascular compartment leading to lower concentrations than in the maternal compartment and some commonly used drugs have been shown to be substrates for these proteins, e.g. methadone. It is suggested that polymorphisms in the genes that encode these transporter proteins may alter their expression and/or function. Hypothesis- Polymorphisms (SNPs) in the ABC transporters ABCB1, ABCG2, ABCC1 and ABCC2 change protein expression and/or function leading to increased fetal exposure demonstrated by increased signs of NAS and/or altered development. Objectives: To determine if genotype alters protein expression and whether there is a relationship between the level of placental multidrug resistance protein P-glycoprotein (P-gp), Breast Cancer Resistance Protein (BCRP), Multidrug Resistance Associated Proteins (MRP1 and MRP2) expression and neonatal and/or developmental outcomes. Methods: Drug using women were recruited. In the immediate postnatal period placental tissue, cord blood and maternal hair samples were taken. Hair was analysed to determine drug use in the preceding 3 months, immunoblotting determined the level of P-gp, BCRP, MRP1 and MRP2 protein expression. Sequenom MassExtend Array produced genotypes from DNA obtained from cord blood. Infants were assessed for NAS at birth, 3 days and 3 weeks. At 8 months and 1 year development was assessed using the Griffiths Mental Development Scales. Plink was used to determine statistically significant associations between genotype and outcome phenotypes. Results- The level of fetal drug exposure did not predict the need for pharmacological treatment for NAS. 32 polymorphisms with significant associations to outcome measures were identified: 4 SNPs significantly altered protein expression, (3 for P-gp and 1 for MRP1). 41 SNPs were associated with changes across 4 of the 5 GMDS subscales. Discussion: No clear relationship between MDRP protein expression and neonatal outcome was noted. However, fetal genotype did influence the expression of P-gp and MRP1 and genotype across all four proteins was associated with significant changes in the measures of infant development. This was a small study and as such generation of susceptible haplotypes was not possible. However the data generated do support the concept. Further larger and longer term prospective studies, building on the experience reported in this thesis, are necessary to generate more data in order to identify haplotypes leading to increased fetal susceptibility to drug exposure.

Inherited disorders of bilirubin metabolism - hereditary hyperbilirubinemias - are metabolic disorders manifested in early childhood. Unconjugated hyperbilirubinemias result from the defect of the enzyme uridine diphosphoglucuronosyltransferase (UGT1A1). UGT1A1 mediates the conjugation of bilirubin with glucuronid acid in hepatocytes and its elimination to water soluble compound. In the next step of bilirubin degradation the transport of conjugated bilirubin from hepatocyte into the bile occure. It is caused by the ATP dependent transporters ABCC2, ATP1B1 and OATP1B3. Mutations in the genes coding the bilirubin transporters results in conjugated hyperbilirubinemia Dubin-Johnson or Rotor syndrome. This study is focused on unconjugated hyperbilirubinemia in adolescents including the non-typical manifestations and the defects of ABCC2 transporter and their phenotype in humans.