Le cancer de la prostate est la troisième cause de mortalité par cancer chez l’homme après les cancers colorectaux et broncho-pulmonaires avec, en 2010, près de 150 000 décès. On voit donc tout l’intérêt d’élaborer de nouvelles stratégies thérapeutiques en essayant de prendre en compte à la fois : i) la métabolisation qui peut modifier in vivo l’efficacité de la molécule initiale et ii) les différences individuelles intervenant à ce niveau du fait de la nature de l’environnement du patient.Nous avons porté notre étude, en collaboration avec l’Ecole HEI de Lille, sur l’intérêt de la Phenstatine (molécule en développement pré-clinique) et de ses métabolites puisque qu’au cours de ces dernières années des résultats thérapeutiques prometteurs ont été obtenus, dans les cancers prostatiques hormono-résistants avec les taxanes, dont le rôle est de stabiliser les microtubules en inhibant leur dépolymérisation.L’objectif de ce travail de thèse a donc été dans un premier temps d’étudier l’effet pharmacologique de la Phenstatine et de ses métabolites issus de sa biotransformation par des microsomes hépatiques humains sur la polymérisation de la tubuline ainsi que sur la prolifération de la lignée cancéreuse prostatique humaine PC3. Nous avons ensuite essayé de déterminer les CYPs responsables de la formation des métabolites identifiés et quantifiés. Enfin, nous avons abordé l’influence de certaines conditions environnementales, plus particulièrement la présence de cadmium, sur le métabolisme de ces composés originaux et donc sur leur activité vis-à-vis de cellules cancéreuses prostatiques. Pour tenter de comprendre la réponse ou la non réponse à ces différents traitements, nous avons suivi les profils d’expression de gènes impliqués dans la prise en charge cellulaire des xénobiotiques en utilisant une technologie fonctionnant à haut débit et basée sur le principe de la PCR quantitative en temps réel (TaqmanTM Low Density Arrays). Un modèle d’étude a pu ainsi être élaboré afin de montrer l’implication de l’environnement sur l’efficacité d’une molécule à visée anticancéreuse. Ce modèle devrait par la suite pouvoir être élargi à d’autres agents participant à la métabolisation des xénobiotiques et déboucher sur la mise en évidence des mécanismes génétiques ou épigénétiques responsables de ces réponses particulières aux traitements anticancéreux. / Prostate cancer is ranked third among fatal cancers, after bronchial and colorectal cancers, with 150,000 deaths recorded in 2010. The design of new prostate cancer drugs should take into account : i) the metabolism which can alter the efficiency of an active compound in vivo, and ; ii) the individual differences in metabolism resulting from patients’ environments. Our study, in partnership with the HEI School of Lille, is concerned with Phenstatin (a compound in pre-clinical development) and its metabolites : indeed, promising therapeutic results have recently been obtained with taxanes in hormone-resistant prostate cancers which stabilize microtubules by inhibiting their depolymerization.The aim of this work was firstly to study the pharmacological effect of Phenstatin and its metabolites, obtained after biotransformation by human liver microsomes, on tubulin polymerization and the proliferation of human prostate cancer cells (PC3 cell line). Secondly, we attempted to determinate the CYPs responsible for the formation of the Phenstatin metabolites we have identified and quantified. Thirdly, we addressed the influence of environmental conditions, more specifically the presence of cadmium, on the metabolism of these novel compounds and their activity towards prostate cancer cells. In order to understand the response or non-response of different treatments, we determined expression profiles of genes involved in the metabolism of xenobiotics by using high throughput technology based on real time quantitative PCR (TaqmanTM Low Density Arrays). A study model was designed in order to show the effect of environmental factors on anticancer compounds’ efficiency. This model should subsequently be transposable to other agents involved in xenobiotic metabolism and reveal genetic or epigenetic mechanisms responsible for individuals’ responses to anticancer treatments.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A fenstatina, quimicamente designada de 4-metoxifenil-3,4,5-trimetoxifenilmetanona, denominada RR07, Ã uma bisarilcetona de esqueleto estilbenÃide que pode ser obtida a partir da combretastatina A4, com reconhecida atividade citotÃxica, por meio da oxidaÃÃo de Jacobsen. Dentre as muitas atividades desencadeadas pelos estilbenos destacam-se atividade antiangiogÃnica, citotÃxica e antitumoral. Para avaliar o seu potencial antineoplÃsico, um estudo farmacolÃgico de suas propriedades anticÃncer foi realizado em vÃrios modelos biolÃgicos. Utilizando o ensaio do MTT foi feito um estudo comparativo da citotoxicidade de molÃculas estilbenÃides com estruturas relacionadas ao composto RR07, onde foi observado que a presenÃa do anel A (3,4,5-trimetoxifenil) Ã essencial para a atividade citotÃxica da molÃcula. Determinou-se inicialmente a atividade citotÃxica, frente a 13 linhagens tumorais pelo ensaio de reduÃÃo do MTT sendo testados 11 compostos, (RR01, RR02, RR03, RR04, RR05, RR06, RR07, RR08, RR09, RR10, RR11), onde o estilbenÃide RR07 destacou-se como um dos mais citotÃxicos apresentando valores de CI50 que variaram de 0,009 a 17,49 M. Posteriormente, os estudos de mecanismo de aÃÃo com o RR07 nas concentraÃÃes de 0,25; 0,50; 1,00; 2,00 e 4,00 M, revelaram reduÃÃo, de forma concentraÃÃo-dependente, na viabilidade celular pelos mÃtodos do azul de tripan e de BrdU (bromodeoxiuridina). As anÃlises morfolÃgicas feitas por hematoxilina/eosina mostraram nÃcleos metafÃsicos, onde no ensaio de incorporaÃÃo por brometo de etÃdio/laranja de acridina evidenciou-se morte celular por apoptose nas concentraÃÃes de 0,25 e 0,50 M, com cÃlulas em necrose nas concentraÃÃes de 1,00; 2,00 e 4,00 M, destacando-se alteraÃÃes como desintegraÃÃo membranar e picnose nuclear, nas concentraÃÃes de 0,25 M e 1,00 M, respectivamente. Nos ensaios por citometria de fluxo foi observado fragmentaÃÃo do DNA com parada de ciclo na fase G2/M a partir da concentraÃÃo 0,25 M. A anÃlise pelo ensaio do cometa, para o RR07 revelou atividade genotÃxica do tipo concentraÃÃo-dependente entre cÃlulas mononucleadas de sangue perifÃrico (PBMC), principalmente em 2,00 e 4,00 M. A avaliaÃÃo do RR07 no ensaio com tubulina isolada revelou inibiÃÃo na polimerizaÃÃo da mesma em uma concentraÃÃo de 10 M. A anÃlise antitumoral evidenciou inibiÃÃo de 30,9% e 48,19%, respectivamente, para as doses de 20 e 40 mg/kg/dia de RR07 por via intraperitoneal (ip), e 55,68% de inibiÃÃo para a associaÃÃo de 10 mg/kg/dia de 5-fluorouracil com 20 mg/kg/dia de RR07 (ip), em camundongos transplantados com Sarcoma 180, onde se verificou reduÃÃo no crescimento tumoral e alteraÃÃes renais iniciais e reversÃveis. Desta forma, a fenstatina, RR07, apresenta-se como uma proposta de ferramenta farmacolÃgica Ãtil para a pesquisa de novos derivados. / The phenstatin, chemically known as 4-methoxyphenyl-3,4,5-trimetoxiphenylmethane, was called in the present study as RR07. This compound is a bisarylketone with stilbenoid skeleton obtained from combretastatin A4, with recognized cytotoxic and antineoplasic activities. Then, a detailed study of RR07 anticancer properties was conducted in several biological models. The cytotoxic activity of eleven compounds (RR01, RR02, RR03, RR04, RR05, RR06, RR07, RR08, RR09, RR10, RR11) was determined against thirteen tumor cell lines by MTT assay. Structure-activity relationship pointed out that the presence of ring A (3,4,5-trimethoxiphenyl) is essential for the cytotoxic potential. The RR07 was one of the most cytotoxic compounds, showing IC50 values ranging from 0.009 to 17.49 ÂM. Investigations on mechanism of action (0.25, 0.50, 1.00, 2.00 and 4.00 ÂM) showed a concentration-dependent manner cell viability reduction (trypan blue dye exclusion test) and proliferation decreasing (BrdU assay). Morphological alterations determined by hematoxylin/eosin and acridine orange/ethidium bromide fluorescent double staining methods indicated an increased number of apoptotic cells at lowest concentrations (0.25 and 0.50 ÂM) and necrotic cells at higher concentrations (1.00, 2.00 and 4.00 ÂM). Flow cytometry analyses showed that RR07 induced DNA fragmentation and cell cycle arrest at G2/M starting at 0.25 ÂM. In the comet assay performed with human peripheral blood mononuclear cells (PBMC), RR07 caused DNA strand breaks only at higher concentrations (2.00 and 4.00 ÂM). Experiments with isolated tubulin, RR07 also induced tubulin polymerization inhibition in a concentration of 10 μM. In vivo antitumor experiments showed that Sarcoma 180 transplanted-mice treated with RR07 intraperitoneally (ip) presented a tumor growth inhibition ratios of 30.9% and 48.19% (20 mg/kg/day and 40 mg/kg/day, respectively) and inhibition of 55.68% in associated treatment (5-Fluoruracil 10 mg/kg/day + RR07 20 mg/kg/day). Histopathological analyses of kidneys, spleen and livers revealed incipient and reversible alterations. In summary, RR07 can be considered as a pharmacological useful tool as well as a lead molecule to obtain novel compounds with low toxicity and promising antitumor properties.