O câncer de mama corresponde a aproximadamente um quarto das neoplasias malignas em mulheres. A incidência do câncer de mama no Brasil é de cerca de 50.000 novos casos por ano, sendo considerado importante problema de saúde pública. HER2 e receptores hormonais (receptores de estrógeno e progesterona) são considerados os mais importantes marcadores prognósticos e preditivos em carcinoma de mama. A amplificação do gene HER2 ou a superexpressão da proteína HER2, que ocorre em cerca de 20 porcento dos carcinomas de mama, está associada a curso clínico mais agressivo e determina elegibilidade para terapia específica anti-HER2 com trastuzumabe. A terapia hormonal reduz em mais de 50 porcento o risco relativo de recorrência da doença em pacientes com tumores sensíveis a esse tratamento. Os testes de HER2 e receptores hormonais são partes essenciais da avaliação clínica das pacientes com carcinoma de mama; resultados precisos são fundamentais na identificação de pacientes que podem ser beneficiadas por terapias específicas. O presente estudo investigou a concordância nos resultados dos testes de HER2 e receptores hormonais determinados por imuno-histoquímica em 500 carcinomas invasivos de mama entre um laboratório referência e laboratórios locais de todas as regiões geográficas do Brasil. Os resultados demonstram baixa concordância geral (171/500 casos, 34,2 porcento) em relação aos resultados do teste de HER2 entre laboratórios locais e referência, o que pode estar relacionado ao baixo volume de testes de HER2 realizados, inexperiência com o sistema de escores de HER2 e/ou questões técnicas relacionadas à imuno-histoquímica nos laboratórios locais. A concordância nos resultados do teste de receptores de estrógeno e progesterona foi de 89,4 porcento (447/500 casos) e de 85,0 porcento (425/500 casos), respectivamente, entre laboratórios locais e referência. Padronização dos testes de HER2 e receptores hormonais com medidas de controle de qualidade rigorosas por laboratórios locais é fortemente recomendada para se evitar o tratamento inadequado de pacientes com câncer de mama / Breast cancer accounts for approximately one quarter of all cancers in females. The incidence of breast cancer in Brazil is about 50,000 new cases per year, and it is considered an important public health problem. HER2 and hormone receptors (estrogen and progesterone receptors) are considered the main prognostic and predictive markers for breast carcinoma. HER2 gene amplification or HER2 protein overexpression, detected in about 20 percent of breast carcinomas, predicts a more aggressive clinical course and determines eligibility for targeted therapy with trastuzumab. Hormonal therapy reduces the relative risk of recurrence by more than 50% in breast cancer patients with hormone-sensitive tumors. HER2 and hormone receptors testing has become an essential part of the clinical evaluation of all breast carcinoma patients, and accurate results are critical in identifying patients who may benefit from targeted therapy. The present study investigated the concordance in the results of HER2 and hormone receptors immunohistochemistry assays performed in 500 invasive breast carcinomas between a reference laboratory and local laboratories from all geographic regions of Brazil. Our results showed an overall poor concordance (171/500 cases, 34.2 percent) regarding HER2 results between local and reference laboratories, which may be related to the low-volume load of HER2 assays, inexperience with HER2 scoring system, and/or technical issues related to immunohistochemistry in local laboratories. The concordance of estrogen and progesterone receptors results was 89.4 percent (447/500 cases) and 85.0 percent (425/500 cases), respectively, between local and reference laboratories. Standardization of HER2 and hormone receptors testing with rigorous quality control measures by local laboratories is highly recommended in order to avoid erroneous treatment of breast cancer patients

Les oestrogènes peuvent favoriser la croissance, la promotion et la progression des cancers hormono-dépendants tels que le cancer du sein, de la prostate et des ovaires. Certains métabolites secondaires de plantes constituent une source importante de phyto-œstrogènes, capables de réduire le risque du cancer en antagonisant les fonctions des hormones. La férutinine (FRT), est une phyto-œstrogène biologiquement active extraite des racines de Ferula hermonis, espèce endémique du Liban. Plusieurs études ont été menées sur l'activité œstrogénique et anticancéreuse de la FRT, cependant son activité cytotoxique sur les lignées de cancer œstrogéno-dépendantes n'a pas été élucidée. La FRT est connue pour son effet agoniste vis-à-vis des récepteurs aux œstrogènes a (REa) et agoniste/antagoniste vis-à-vis des REß. Dans un premier temps, la production de la FRT a été optimisée par une hémisynthèse à partir de l'hydrolyse basique de l'extrait brut. Son activité anticancéreuse sur des lignées du sein MCF-7 (REa+, REß+) et MDA-MB-231(REa-, REß-), de la prostate PC-3 (REa+,REß+), DU 145 (REa-, REß+) et 22Rv1 (REa-, REß-) et des ovaires OVCAR-3 (REa+, REß+), SKOV-3 (REa muté, REß+) et IGROV-1 (REa-, REß-) a été testée. Un effet biphasique a été observé sur la prolifération des cellules du carcinome mammaire MCF-7, où son activité proliférative a été corrélée avec la stimulation des REs. La FRT est capable à des concentrations élevées d'inhiber la prolifération des lignées cellulaires cancéreuses et d'induire un arrêt du cycle cellulaire au niveau de la phase pré G0/G1 agissant ainsi via un mécanisme pro-apoptotique. L'efficacité de la férutinine réside dans son pouvoir à cibler spécifiquement les cellules souches/progénitrices cancéreuses chez les lignées cellulaires étudiées qui sont à la base de la réémission tumorale. Cependant, son activité antiproliférative est considérée moyenne puisqu'elle ne peut pas déclencher à des faibles concentrations une activité pure antagoniste des œstrogènes. Les travaux de thèse se sont ensuite focalisés sur la synthèse de composés analogues de la FRT en conservant sa structure indispensable à son activité. Nous avons élaboré un filtre in silico de chimiothèques d'antagonistes potentiels des REs. Ce nouvel outil d'arrimage moléculaire a guidé la synthèse des analogues de la FRT en améliorant leur fixation en position antagoniste dans le site de liaison des REs. L'arrimage moléculaire de la férutinine dans le site actif des REs a confirmé structuralement sa double compétence œstrogénique (agoniste/antagoniste) observée in vitro. Une douzaine d'analogues de la FRT a été synthétisée et testée pour son pouvoir antiprolifératif sur les lignées cancéreuses considérées. Des résultats prometteurs ont été obtenus notamment pour trois analogues sur les lignées cancéreuses mammaires (3c' et 2c'), prostatiques (2c') et ovariennes (3b). Ces composés ont montré une sélectivité vis-à-vis des lignés cancéreuses. Ces analogues constitueront alors des candidats pour une éventuelle plateforme de développement d'agents anticancéreux. / Estrogens are key regulators of cell growth in hormone-dependent cancers such as breast, prostate and ovarian. Phyto-estrogens are a diverse group of plant-derived compounds, exhibiting potential benefits for chemoprevention by antagonizing the function of estrogens. Ferutinin (FRT) is the main active phyto-chemical extracted from the endemic plant of Lebanon, Ferula hermonis. Several studies were conducted on the estrogenic and anti-proliferative activities of FRT; nevertheless, its cytotoxic activity against estrogen-dependent cancers is not yet elucidated. FRT has been reported as agonist to estrogen receptor a (ERa) and agonist/antagonist to ERß. FRT production was first optimized by hemi-synthesis from basic hydrolysate of crude root extract. The anticancer properties of FRT was assessed against breast (MCF-7, MDA-MB-231), prostate (PC-3, DU 145, 22Rv1) and ovarian (OVCAR-3, SKOV-3, and IGROV-1) cancer cell lines. A biphasic effect was observed on the proliferation of mammary MCF-7 cell line, where the proliferative activity was correlated to ER stimulation. FRT inhibited the proliferation of all studied cell lines at high concentrations and induced a pre G0/G1 cell cycle arrest via a pro-apoptotic mechanism of action. FRT targeted the enriched population of cancer stem cells/progenitors which is responsible for tumor reemission. However, its antiproliferative activity is considered weak since it cannot trigger at low concentrations pure estrogen antagonistic activity. This project emphasizes next on the synthesis of FRT analogues by preserving its active structure. We have created an in silico filter of chemical compounds that might act as potential antagonists to ERs. This novel molecular docking tool was used to design FRT derivatives by enhancing their antagonist position inside the binding cavity of ERs. Docking results of FRT in the binding site of ERs confirmed structurally the dual potency that exerts this molecule (agonist/antagonist) in vitro. A list of FRT analogues were synthesized and tested for their anti-proliferative activity against the studied cell lines. Promising results were obtained with three ferutinin analogues on the proliferation of breast (3c' and 2c'), prostate (2c') and ovarian (3b) cancer cell lines. These compounds were also shown to be more selective to cancer cell lines. The cytotoxic properties of these analogues suggest that they could be promoted as potential candidates for useful anticancer therapy.

No description available.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-11T12:24:30Z No. of bitstreams: 1 patriciaoliveiracarmo.pdf: 901114 bytes, checksum: 4238f828115db8965f8df71f43a82da1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T17:05:15Z (GMT) No. of bitstreams: 1 patriciaoliveiracarmo.pdf: 901114 bytes, checksum: 4238f828115db8965f8df71f43a82da1 (MD5) / Made available in DSpace on 2016-01-25T17:05:15Z (GMT). No. of bitstreams: 1 patriciaoliveiracarmo.pdf: 901114 bytes, checksum: 4238f828115db8965f8df71f43a82da1 (MD5) Previous issue date: 2015-06-19 / Em geral, o câncer de mama subtipo luminal exibe melhor prognóstico em relação aos outros subtipos tumorais. No entanto, a doença nesta condição pode assumir uma evolução desfavorável em algumas circunstâncias, o que sinaliza para a necessidade de melhor entendimento sobre o comportamento deste subtipo tumoral. O presente estudo teve por objetivo estimar a sobrevida livre de doença de mulheres em cinco anos com câncer de mama subtipo luminal e avaliar as variáveis prognósticas, clínicas, sociodemográficas, histopatológicas, relacionadas à utilização dos serviços de saúde e ao tratamento visando conhecer o impacto destas e sua implicação na recorrência e sobrevida da população estudada. Os dados foram obtidos a partir de uma coorte de base hospitalar, composta por 331 mulheres diagnosticadas com a doença no período entre 2003 e 2005, com perfil imunohistoquímico compatível com tumor luminal, não metastático (estadios I, II e III), atendidas em hospital referência em Oncologia no Município de Juiz de Fora – MG. A sobrevida livre de doença em cinco anos foi de 79,5% (IC95%: 74,6-83,6). Na análise univariada, observou-se associação da recorrência do tumor com o tipo de serviço de saúde, estadiamento, tamanho tumoral, comprometimento linfonodal e número de linfonodos comprometidos, quimioterapia e hormonioterapia (p<0,05), sendo verificada menor recorrência para as mulheres que frequentaram o serviço privado, que apresentaram doença inicial, menor tamanho tumoral e ausência de comprometimento linfonodal axilar e que foram submetidas a hormonioterapia. No modelo multivariado, permaneceram gravidade da doença e hormonioterapia como os fatores prognósticos mais importantes. As técnicas de biologia molecular representam o futuro do tratamento do câncer e também para os tumores luminais. Deve-se garantir o acesso ao tratamento hormonal quando indicado e os estágios avançados devem ser objeto de abordagem terapêutica mais ampliada. / Luminal breast cancer usually has a better prognosis in relation to other tumoral subtypes. Nonetheless, the illness in this point can evolve unfavorably in some circumstances what signals the need for a better understanding about this tumoral subtype behavior. The present study aimed at estimating the diseasefree survival of women with luminal breast cancer in five years. In this study, many variables have been evaluated, including prognostic, clinic, sociodemographic, histopathological and related to the use of public health services and treatment, aiming to get to know their impact and implications on recurrence and survival among the population of the study. The database was a hospital based cohort study, composed of 331 women diagnosed with the disease between 2003 and 2005, with immunohistochemical profile compatible with luminal breast cancer, non-metastatic (stages I, II or III), treated in a hospital seen as a reference for cancer care in Juiz de Fora, MG. The study showed a disease-free survival of 79.5% (IC95%: 74.6-83.6) in five years. The univariate analysis has shown an association of tumor recurrence with the type of health care, staging, tumor size, lymph node involvement and their number, chemotherapy and hormonal therapy (p<0.05) and it has indicated better survival rates among women who used private health care, who are in an initial stage, with smaller tumors, no axillary involvement and who used hormonal therapy. In the multivariate model, there remained gravity of the illness and the use of hormonal therapy as the most important prognostic factors. Molecular biology techniques represent the future for cancer treatment and also for luminal tumors. Access to hormonal therapy should be granted whenever prescribed and advanced stages must receive an amplified range of therapeutic approach.

Chlamydia is the most common bacterial sexually transmitted infection in the United States and worldwide. It often goes unnoticed due to lack of symptoms and left untreated it can ascend the female genital tract to cause sequelae like pelvic inflammatory disease and irreversible tubal infertility. In reproductive-aged women, female sex hormones estrogen (E2) and progesterone (P4) concentrations fluctuate during the menstrual cycle and are influenced by hormonal contraceptives and hormone replacement therapy. E2 and P4 influence genital Chlamydia infection in women and mice, but these multifactorial interactions are not entirely mapped out. The complex interplay of E2 and P4 with Chlamydia and the host response demand further study to determine the effect of hormonal environment and host susceptibility to Chlamydia. E2 primarily signals through estrogen receptors (ER) ERα and ERβ. We used ERα or ERβ knockout (KO) mice to study the role of E2 and ERs in chlamydial progression and examined the host immune response at day 9 post-infection, when we expected the immune response to be the most robust. ERαKO, but not ERβKO mice had significant differences in the progression of Chlamydia and the host immune response. Future studies should test the immune response at additional timepoints, and a model should be utilized wherein ERα and ERβ are simultaneously silenced by chemical knockdown of ERβ in ERα knockout mice using ER agonist ICI 182, 680. 3 Mice are widely used in Chlamydia research, but due to its short estrus cycle, infection cannot be established naturally before infected cells are shed. To overcome this, mice are pretreated with depot medroxyprogesterone acetate (DMPA), an exogenous progesterone that halts the estrus cycle. However, a mouse model not reliant on DMPA pretreatment is needed because 1.) DMPA can affect the immune response and 2.) the hormonal environment in women is not static. Our model uses mice that are ovariectomized to stop the production of endogenous E2 and P4, then treated with physiologically relevant levels of E2 and P4 via implantation of a hormone-filled capsule. We observed that E2 protected mice from Chlamydia, making our model a good alternative for in vivo Chlamydia studies.

L’imagerie moléculaire avec des biomarqueurs radiomarqués par des émetteurs de positons est couramment utilisée dans les cancers mammaires infiltrants pour la stadification initiale ou en cas de récidive, et également pour l’évaluation de la réponse tumorale en situation néoadjuvante et métastatique. Après quelques notions générales sur les cancers mammaires et le rôle alloué à l’imagerie moléculaire, les résultats des travaux axés sur l’imagerie moléculaire des cancers mammaires que j’ai encadrés et auxquels j’ai contribués au sein de l’équipe de Médecine Nucléaire de l’Institut Curie - Saint-Cloud sont présentés. Ces études ont évalué la valeur de la Tomographie par Emission de Positons au FluoroDesoxyGlucose (TEP-FDG) en cas de suspicion biologique de récidive, ou pour la stadification initiale et l’évaluation de la réponse tumorale à la Chimiothérapie NéoAdjuvante (CNA) des cancers mammaires inflammatoires. Notre équipe a également étudié la valeur pronostique de la réponse tumorale à l’hormonothérapie par la TEP-FDG, en situation métastatique. La problématique de l’évaluation précoce de la réponse tumorale à la CNA par l'imagerie moléculaire m’a amené à étudier un modèle murin transgénique de cancer mammaire avec d’autres biomarqueurs que le FDG, à savoir la FLuoroThymidine (FLT) et le pertechnetate. Des outils de quantification de la charge tumorale ont pu être développés et ont permis d’évaluer la réponse tumorale à des drogues cytotoxiques lors d’un suivi longitudinal, mais ce travail s’est heurté aux limites de l’imagerie préclinique. Les résultats des études cliniques sur l’évaluation précoce de la réponse tumorale à la CNA sont ensuite exposés, avec le FDG comme biomarqueur en insistant sur l’influence du phénotype moléculaire sur les paramètres définissant une réponse métabolique. L’état des connaissances et les perspectives avec d’autres biomarqueurs que le FDG, à savoir la FLT et le FluoroEStradiol (FES), pour étudier respectivement la prolifération cellulaire tumorale et la présence et la fonctionnalité des récepteurs aux estrogènes, puis l’imagerie en développement de l’Human Epidermal Growth Factor Receptor-2 (HER2), destinés à la fois à la sélection de patients candidats à des thérapies innovantes et à la prédiction et l’évaluation de la réponse tumorale aux thérapies sont discutées. / Molecular imaging with biomarkers radiolabeled by positron emitters is commonly used in invasive breast cancers for initial staging or restaging, and for assessment of tumor response in neoadjuvant and metastatic settings. After general concepts of breast cancers and of the place of molecular imaging, results of studies I supervised and to which I contributed within the nuclear medicine team from Curie Institute - Saint-Cloud focused on molecular imaging in breast cancers are presented. These studies assessed the value of Positron Emission Tomography using FluoroDeoxyGlucose (FDG-PET) in recurrence suspected on tumor marker rising and in staging and assessment of tumor response to neoadjuvant chemotherapy (NACT) in inflammatory breast cancers. Moreover our team has studied the prognostic value of tumor response to endocrine therapy by FDG-PET in metastatic breast cancers. The problem of early assessment of tumor response to NACT by molecular imaging has led me to study a transgenic mouse model with other biomarkers than FDG, namely FLuoroThymidine (FLT) and pertechnetate. Quantification tools of tumor burden have been developed and allowed assessment of tumor response to cytotoxic drugs during a longitudinal follow-up of this model, but several limitations of preclinical imaging were encountered. Results of clinical studies on early assessment of tumor response to NACT with FDG as a biomarker are exposed, with emphasis on the influence of the molecular subtype on parameters defining a metabolic response. State of the art and perspectives with FLT and FluoroEStradiol (FES), as biomarkers of proliferation and of estrogen receptors respectively, then imaging of Human Epidermal Growth Factor Receptor-2 (HER2), for both selection of patients to innovative therapies and prediction and assessment of tumor response to systemic therapies are discussed.

No description available.

The signaling mechanisms involved in UVB-induced skin cancer are complex and although the scope of this work is inherently limited in focus, the findings may provide insight into how estrogen receptor signaling impacts cell growth, senescence, and apoptosis to protect keratinocytes. Additional signaling due to E2-activation of the estrogen receptor may provide back-up or redundant pathways in response to UVB.

La barrière intestinale est la plus grande surface de contact entre le milieu extérieur et le milieu intérieur. Outre ses fonctions d'absorption des nutriments, elle exerce un rôle important de défense contre les agents indésirables (toxines, bactéries) contenus dans la lumière intestinale. Une augmentation de la perméabilité intestinale a été observée chez les patients atteints du syndrome de l'intestin irritable (SII) ou des maladies inflammatoires chroniques de l'intestin (MICI). Cette hyperperméabilité intestinale est contemporaine d'une hypersensibilité viscérale à la distension de la paroi intestinale. Des travaux récents rapportent également une augmentation de l'activité protéolytique du contenu intestinal dans le cadre de ces deux pathologies. Les estrogènes, par leurs propriétés anti-inflammatoires et leur capacité à moduler la perméabilité intestinale par activation de leurs récepteurs (REs) peuvent contribuer à l'amélioration des symptômes associés à ces pathologies digestives. Une variété de traitements médicaux a été utilisée pour la prise en charge thérapeutique du SII et de MICI. Cependant, les patients questionnent les cliniciens sur des conseils diététiques susceptibles d'améliorer leur qualité de vie. Ainsi, l'objectif de ce travail était d'évaluer les effets et les mécanismes d'action impliqués, d'un traitement par du germe de soja fermenté (SG) sur l'hyperalgésie viscérale et l'hyperperméabilité intestinale dans des modèles animaux mimant le SII et les MICI afin de proposer des futures allégations santé à ce produit. Le rationnel de l'évaluation de cet ingrédient était basé sur sa composition intéressante, à savoir, sa teneur en composés à propriétés estrogéniques (isoflavones) et sa capacité à inhiber les protéases (BBI). Dans un premier temps, nous avons montré qu'un traitement oral de 15 jours par le SG diminue de façon significative l'hypersensibilité viscérale, l'hyperperméabilité intestinale ainsi que l'augmentation de l'activité protéolytique induites par un stress de contrainte chez le rat. La diminution de la perméabilité intestinale implique une surexpression de l'occludine, protéine des jonctions serrées. De même, le traitement par du SG réduit la densité des mastocytes au niveau du côlon. Tous les effets préventifs du SG sauf ceux sur l'activité protéolytique sont estrogéno-dépendants car bloqués par l'antagoniste des REs. Dans un second temps, nous avons montré qu'un traitement préventif par le SG pendant 15 jours présente des effets protecteurs vis-à-vis d'une inflammation intestinale induite par du TNBS. Le SG atténue la sévérité de l'inflammation, l'hyperperméabilité, l'hypersensibilité et l'augmentation de l'activité protéolytique induites par la colite. Les effets anti-inflammatoires du SG sont à la fois dépendants des phytoestrogènes et du contenu de l'ingrédient en BBI. En conclusion, ces données sont prometteuses pour une future utilisation du SG dans la gestion thérapeutique du SII et des MICI comme traitement adjuvant / The intestinal barrier is the largest area of contact between the external environment and internal environment. In addition to its function of nutrient absorption, the intestinal barrier plays a key role of defense against noxious agents (toxins, bacteria) contained in the intestinal lumen. An increase in intestinal permeability was observed in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). This intestinal hyperpermeability was often associated with visceral hypersensitivity to colorectal distension. Recent studies also report an increase in the proteolytic activity in patients with IBS or IBD. Estrogens, through their anti-inflammatory properties and their ability to modulate intestinal permeability by activating estrogen receptors (ERs), can play an important role in these digestive diseases. A variety of medical therapies have been used for treatment of IBS and IBD. However, patients question clinicians about dietary suggestions to improve their symptoms and quality of life. Thus, the aim of this study was to evaluate the effects and mechanisms of action involved of a treatment with fermented soy germ (SG) on visceral hyperalgesia, intestinal hyperpermeability in animal models mimicking the IBS and IBD. The evaluation of this ingredient was based on its interesting composition, i.e its content of isoflavones and a family of serine protease inhibitors known as BBI. Initially, we demonstrated that an oral treatment of 15 days by SG significantly reduces visceral hypersensitivity, intestinal hyperpermeability and increased proteolytic activity induced by acute stress in the rat. Decreased intestinal permeability is due to overexpression of occludin, a transmembrane tight junction protein. Similarly, treatment with SG reduces the density of colonic mast cells. All preventive effects of SG except those on the proteolytic activity are estrogen-dependent because blocked by the antagonist of ERs. In a second step, we demonstrated that a treatment for 15 days with SG induces protective effects against intestinal inflammation induced by TNBS. SG reduces the severity of colitis, decreases TNBS-induced hyperpermeability, hypersensitivity and increased proteolytic activity. The anti-inflammatory effects of SG are estrogen and/or BBI dependent. In conclusion, these data are promising for future use of the SG as adjuvant therapy in IBS and IBD management

La résistance aux anti-aromatases (AAs) constitue un obstacle thérapeutique majeur dans le traitement des cancers du sein RE+. Les objectifs de ce travail étaient : (i) de caractériser les événements moléculaires associés à la résistance acquise aux AAs ; (ii) d’identifier de manière globale de nouveaux profils de miRNAs spécifiquement associés à la résistance aux AAs. Notre étude a mis en évidence le rôle central de la voie Akt/mTOR dans la résistance acquise et de novo aux AAs dans des modèles cellulaires, mais également dans des échantillons de patientes ayant récidivé sous anastrozole. La combinaison d’un AA avec le MK-2206, inhibiteur d’Akt ou avec la rapamycine, inhibiteur de mTOR, augmente la sensibilité à l’AA dans les cellules contrôles et est suffisante pour surmonter la résistance et restaurer la sensibilité à l'hormonothérapie dans les cellules résistantes. Notre travail propose également un modèle de résistance acquise aux AAs basé sur la sélection de cellules « cancer-initiating-like » dotées de propriétés d'auto-renouvellement, d’une résistance intrinsèque aux AAs et d’une sensibilité au MK-2206. Notre étude à grande échelle des miRNAs a identifié la voie Akt/mTOR comme une des cibles privilégiées de ces miRNAs. Nous avons identifié et validé trois miRNAs dérégulés capables de moduler le statut d’activation de la voie Akt/mTOR, qui représentent des cibles potentielles. En conclusion, notre projet a mis en évidence de nouvelles voies de signalisations ciblées par ces miRNAs et de nouveaux évènements moléculaires, qui représentent des candidats potentiels dans la résistance aux AAs / Resistance to aromatase inhibitors (AIs) remains a major drawback in the treatment of ER+ breast cancers. Our objectives were (i) to characterize molecular events associated with acquired AI resistance (ii) to capture a global view of the miRNA expression profiles associated with AI resistance. Our results showed the major role of the Akt/mTOR pathway in both de novo and acquired resistance to AI in cellular models and also in breast tumors of patients who relapsed under anastrozole. Combining AI with the Akt inhibitor MK-2206 or with the mTOR inhibitor rapamycin increased sensitivity to this AI in the control cells and was sufficient to overcome resistance and restore sensitivity to endocrine therapy in the resistant cells. Our findings propose a model of AI-acquired resistance based on the selection of cancer-initiating-like cells possessing self-renewing properties, intrinsic resistance to AI and sensitivity to MK-2206. Our large-scale study identified the Akt/mTOR pathway as one of the main targets of the deregulated miRNAs. We identified and validated three miRNAs able to modulate the Akt/mTOR activation status, suggesting these miRNAs as potential targets. To conclude, our project identified new miRNA-targeted signaling pathways and new molecular events, representing strong candidates in the mediation of AI resistance