Age-related degeneration of the equine endometrium is an established and important cause of fertility problems in thoroughbred mares, causing great loss to the industry. As a part of the age-related endometrial degeneration complex, an excessive deposition of collagen leading to endometrial fibrosis is particularly important due to the limitations it causes to uterine function. The consequences include reduced efficacy of uterine defence mechanisms and a decrease in the uterine capacity for foetal nutrition. Extensive research into the process of fibrosis in other organs has shown that this condition results from the malfunction of physiological tissue repair mechanisms. These mechanisms revolve around tissue fibroblasts that due to continuous stimulation secrete excessive amounts of collagen and inhibit the activation of factors essential to the normal collagen degradation occurring in scar resolution. Among these factors are the MMPs, an enzyme family with the ability to degrade extracellular matrix components such as collagen during the normal repair mechanisms following tissue injury. The malfunction in the regulation of these enzymes is important in the development of fibrosis in the liver and other organs. In this study it was demonstrated that MMPs are involved in the acute uterine inflammatory response and that they were secreted by infiltrating inflammatory cells. The cellular mechanisms observed during endometritis in normal mares were comparable to the normal repair mechanisms known to be altered in the fibrosis of other organs. These enzymes were present in equine foetal fluids, and their regulation may be important in the process of abortion and stillbirth. It was demonstrated that inbreeding may be correlated with increased deposition of endometrial collagen in a study population of the Icelandic horse breed even though this breed appears to exhibit less severe endometrial degeneration than what is known in lighter breeds. It is likely that genetic predisposition leads to the disruption of normally self-limiting inflammatory and repair mechanisms in the endometrium, resulting in constant activation of collagen synthesis by local and infiltrating cells. This thesis has shown that tissue repair mechanisms involving MMPs are likely to be involved in endometrial fibrosis in the mare. An inherent alteration in these mechanisms may play a role in the pathogenesis of this condition, and might arise due to genetic predisposition. Further understanding of the pathways leading to excess collagen amounts in the endometrium may produce preventative measures, and even therapeutic targets.

Matrix metalloproteinases (MMPs) are required for tissue remodelling processes, including angiogenesis. MMP activity is generally proangiogenic but MMP-12 is suggested to be antiangiogenic and its precise role is still unclear. The work in this thesis describes the synthesis of an MMP-12 inhibitor and activity probe to address the hypothesis that MMP-12 inhibits angiogenesis. An inhibitor, synthesised in-house, selectively inhibited MMP-12 in in vitro recombinant enzyme assays. An activity probe, also synthesised in-house, was selective for MMP-12 in in vitro recombinant enzyme assays. The function of MMP-12 during angiogenesis was assessed using murine models of angiogenesis; the in vivo sponge implantation, and the ex vivo aortic ring assays. Angiogenesis and MMP activity were imaged in vivo in sponges in C57Bl6/J mice over 7 − 21 days (D) using commercial probes (MMPSense™ and AngioSense™). MMP-12 protein concentration and activity were higher in sponges during early angiogenesis (D 3 − 7) when gene expression of vascular endothelial growth factor (a proangiogenic marker) was also high. Gene expression for MMP-12 and platelet-derived growth factor receptor (a marker of vascular maturation) were both higher on D 21 as angiogenesis started to stabilise. The MMP-12 activity probe was unsuccessful in selectively detecting MMP-12 activity in sponge lysate mixtures from D 7 − 21. Administration of an MMP-12 inhibitor did not increase angiogenesis in the sponges in vivo. Additionally, sponges implanted in MMP-12-/- mice did not exhibit significant changes in angiogenesis or MMP activity when imaged in vivo using commercial probes (MMPSense™ and AngioSense™) on D 7. Supporting this, histological analysis of the sponges (removed on D 21) showed that deletion of MMP-12 also did not increase angiogenesis within the sponges.

Compelling evidence indicated that major risk factors for atherosclerosis such as oxidatively modified low density lipoprotein (oxLDL), high glucose, and reactive oxygen species promote endothelial cell apoptosis and thereby may contribute to the initiation of atherosclerotic lesion formation. Using fast protein liquid chromatography (FPLC), plasma LDL from familial hypercholesterolemic (FH) patients were separated into five subfractions, L1¡VL5. Among them, L5 subfraction was highly electronegative and suppressed DNA synthesis in cultured bovine aortic endothelial cells (BAEC) and stimulated mononuclear cell adhesion to cultured endothelial cells in vitro. Because impaired angiogenesis plays an important role in the pathogenesis of atherosclerosis, the anti-angiogenic functions of LDL subfractions from FH subjects were examined. Subconfluent BAEC (6 to 10 passages) maintained in DMEM containing 10% serum were treated with LDL subfractions at a dose of 20 £gg/ml, and the effects on anti-angiogenic functions, including cell proliferation, migration, apoptosis, tube formation, and secretion of matrix metalloproteinase (MMP) were determined. Similar to Cu2+ ox-LDL, FH-L4 and FH-L5 inhibited cell proliferation to 80.9¡Ó2.4% (p<0.05) and 58.5¡Ó4.3% of control (p<0.001), respectively, while the other FH (L1-L3) and all subfractions isolated from normocholesterolemic (N) subjects had negligible effects. Similarly, FH-L4 and -L5, but not FH-L1 to -L3, retarded cell migration to 326.9 ¡Ó 19.4 (p<0.05) and 215¡Ó16 cells (p<0.001 with the control values of 402¡Ó34 cells), respectively. FH-L5 induced almost 20% of BAEC to undergo apoptosis; FH-L4 caused very mild effects, and other subfractions did not affect apoptosis In addition, FH-L4 and -L5 perturbed tube formation by BAEC in culture (5.8¡Ó0.2 and 3.4¡Ó0.4, respectively, versus control 8.5¡Ó1.5 tubes). Finally, FH-L4 and -L5 inhibited secretion of MMP-2 by BAEC (72.7¡Ó6.9 and 18.9¡Ó4.8% of control, respectively). The results demonstrate that FH-L5 potently affects multiple processes that are vital to normal angiogenesis, FH-L4 had milder effects, and other FH and N subfractions had negligible effects. In turn, these effects in vitro on processes pivotal to angiogenesis are consistent with potential effects of ox-LDL on endothelial dysfunction during atherogenesis in vivo.

Μελετήθηκε η επίδραση ουραιμικού ορού στο σύστημα των μεταλλοπρωτεϊνασών MMP-2 και MMP-9 και των αναστολέων τους TIMP-1 και TIMP-2 καθώς και σε βασικές βιολογικές δράσεις των ενδοθηλιακών κυττάρων σε καλλιέργειες HUVEC. Ο ορός συλλέχθηκε από ασθενείς που υποβάλλονταν σε συνεδρίες αιμοκάθαρσης (πριν και μετά τις συνεδρίες). Διαπιστώθηκε πως ο ουραιμικός ορός μειώνει την ικανότητα πολλαπλασιασμού, μετανάστευσης και επούλωσης τρύματος, ενώ επάγει την απόπτωση. Επιπλέον, ο ουραιμικός ορός επάγει τις μεταλλοπρωτεϊνάσες MMP-2 και MMP-9, καταστέλλει τους αναστολείς τους TIMP-1 και TIMP-2 και μειώνει την παραγωγή κολλαγόνου τύπου IV και ελαστίνης. / -

ABSTRACT Background Interleukin-7 (IL-7) is a cytokine crucial for T-cell development and homeostasis. IL-7 is thought to be a limited resource, and its interaction with the IL-7 receptor (IL-7R) has effects on increasing cell survival, proliferation and cytolytic function. Considering the roles of IL-7, it is no surprise that the expression of the IL-7 receptor alpha chain (CD127) is tightly regulated. Despite increased levels of soluble CD127 (sCD127) being detected in a number of disease states and being associated with disease activity, the biological function of sCD127 and its clinical relevance remains to be established. In this study, I explore the post-translational mechanisms leading to the release of the soluble form of CD127 receptor through IL-7 and αCD3/αCD28 stimulation. Here I specifically established two different mechanisms by which CD127 is processed; shedding of the receptor ectodomain and clipping. Results In CD8+ T-cells, IL-7 plus TcR stimulation resulted in an increased release of sCD127. Here I found that matrix metalloproteases (MMPs), in particular MMP-9, have a role in the proteolytic clipping of CD127 resulting in the release of sCD127. In addition, I found that IL-7 plus TcR stimulation resulted in an increase in MMP activity and this activity was particularly dampened when MMP-2 and -9 inhibitors were used. I also found that neither MMP-3 nor cysteine and serine proteases seem to be directly involved in the generation of sCD127. Using a biotinylation assay I found that CD127 is being shed from the surface of CD8+ T-cells as well as thymocytes through a MMP-independent mechanism. Conclusion These results demonstrate that MMPs (in particular MMP-9) have a role in the generation of sCD127. Further studies are required to determine the specific sheddase responsible for the ectodomain shedding of CD127, as well as the details behind the regulation of MMP-9 activity both in CD8+ T-cells and thymocytes. A thorough understanding of these mechanisms will aid in the development of alternative and more specific strategies to control IL-7 mediated processes in both normal and disease states.

Salamanders have an extraordinary ability to regenerate appendages after loss or amputation, irrespective of age. My dissertation research explored the possibility that regenerative ability is associated with the evolution of novel, salamander-specific genes. I utilized transcriptional and genomic databases for the axolotl to discover previously unidentified genes, to the exclusion of other vertebrate taxa. Among the genes identified were multiple mmps (Matrix metalloproteases) and a jnk1/mapk8 (c-jun-N-terminal kinase) paralog. MMPs function in extracellular matrix remodeling (ECM) and tissue histolysis, processes that are essential for successful regeneration. Jjnk1/mapk8 plays a pivotal role in regulating transcription in response to cellular stress stimuli, including ROS (reactive oxygen species). Discovery of these novel genes motivated further bioinformatic studies of mmps and wet-lab experiments to characterize JNK and ROS signaling. The paralogy of the newly discovered mmps and orthology of 15 additional mmps was established by analyses of predicted, protein secondary structures and gene phylogeny. A microarray-analysis identified target genes downstream of JNK signaling that are predicted to function in cell proliferation, cellular stress response, and ROS production. These inferences were validated by additional experiments that showed a requirement for NOX (NADPH oxidase) activity, and thus presumably ROS production for successful tail regeneration. In summary, my dissertation identified novel, salamander-specific genes. The functions of these genes suggest that regenerative ability is associated with a diverse extracellular matrix remodeling and/or tissue histolysis response, and also stress-associated signaling pathways. The bioinformatic findings and functional assays that were developed to quantify ROS, cell proliferation, and mitosis will greatly empower the axolotl embryo model for tail regeneration research.

Au cours de l'invasion tumorale, la matrice extracellulaire du tissu broncho-pulmonaire, riche en élastine, subit de nombreux remaniements. La dégradation de cette élastine conduit à la production de peptides bioactifs. Ces peptides d'élastine (PE) possèdent un récepteur spécifique, le complexe récepteur de l'élastine (CRE), et peuvent également interagir avec l'intégrine alphavbeta3 et la galectine-3. Dans cette étude, nous avons étudié le rôle des PE et de leurs récepteurs dans la progression tumorale des carcinomes broncho-pulmonaires.Des cellules épithéliales bronchiques tumorales sont incubées in vitro avec un mélange de PE, la kappa-élastine (kE), ou avec des peptides synthétiques. Le traitement par les peptides entraine une augmentation de la capacité infiltrante des cellules invasives associée à un relargage précoce de MMP 2, MMP 9 et uPA mais n'a pas d'effet sur la prolifération et le phénotype cellulaire. Les niveaux d'ARNm des 3 protéases stimulées ne sont pas modifiés et ni l'actinomycine D, ni le cycloheximide ou la bréfeldine A ne sont capables d'inhiber les effets liés à la kE. Ces effets ne sont pas non plus inhibés par le lactose et les autres antagonistes des trois récepteurs. Enfin, les peptides VGVAPG et GRKRK, présentant les séquences spécifiques reconnues par les récepteurs, ne réussissent pas à reproduire les effets observés avec la kE, alors que des nonapeptides les reproduisent de façon quasi-identique.Ces résultats montrent que les PE régulent la capacité invasive des carcinomes broncho-pulmonaires, via le relargage d'enzymes protéolytiques. Cette modulation mettrait en jeu des mécanismes post-traductionnels et un récepteur lactose-insensible, différent du CRE, de l'intégrine alphavbeta3 et de la galectine-3, et reconnaissant des nonapeptides d'élastine. / Elastin-rich lung extra-cellular matrix is largely remodeled during tumor invasion. Elastin degradation produces peptides displaying a wide range of biological activities. These elastin derived peptides (EP) interact with the Elastin Receptor Complex (ERC) but also bind to alphaVbeta3 integrin and galectin-3. In this study, we explored the role of EP and their receptors in tumor progression of lung carcinomas.In vitro, lung tumor cells were incubated in presence of kappa-elastin (kE), a mix of EP or with synthetic elastin peptides. EP treatment induced an increase of invasive capacity of invasive cells with quickly increased levels of MMP-2, MMP 9 and uPA but had no effect on cell proliferation and phenotype. Interestingly, protease regulation was not observed at the mRNA level and actinomycin D, cycloheximide and brefeldin A were unable to inhibit kE effects. These effects could not be inhibited either by classical receptor antagonists including lactose or blocking antibodies. Finally, synthetic peptides VGVAPG and GRKRK, displaying receptor-specific sequences, failed to reproduce kE effects whereas nonapeptides partially mimicked them.These results demonstrate that treatment with EP up-regulates invasiveness of lung tumor cells via the release of proteolytic enzymes. This modulation involves post-translational mechanisms and a lactose-insensitive receptor, different from the ERC, alphaVbeta3 integrin and galectin-3 and recognizing nonapeptidic sequences.

Made available in DSpace on 2016-06-02T19:22:10Z (GMT). No. of bitstreams: 1 5684.pdf: 2471155 bytes, checksum: f035dbceafb88325d3cb0d3fb8280603 (MD5) Previous issue date: 2013-12-10 / Financiadora de Estudos e Projetos / Matrix metalloproteinases (MMPs) are key factors in tumor progression that allow tumor cells to modify the extracellular matrix (ECM) and to release cytokines, growth factors being activated by cell surface molecules such as the integrins. Integrins are major adhesion receptors of cell surface that connect the cells to the external environment enabling its movement. Integrins activate signaling cascades that influence the adhesion, survival and cell proliferation. Important inhibitors of these molecules were found in snake venoms called disintegrins. Alternagin-C (ALT-C) a disintegrin from Rhinocerophis alternatus snake venom has affinity with &#945;2&#946;1 integrin therfore modulating cell adhesion, migration and proliferation. However, the effect of ALT-C on MMP activity has not been described yet. Here, we have found that, ALT-C increased cell migration in MDA-MB-231 at lower concentration (10 nM) and it decreased cell migration at higher concentrations (40, 100 and 1000 nM). ALT-C was able to inhibit MMP-9 activity in human breast cancer (MDA-MB-231) conditioned medium and MMP-2 activity in fibroblastas and human microvascular endothelial cells (HMEC-1) conditioned medium. ALT-C also modulated the expression of angiogenic genes such as VEGF, c-MYC, MMP-2 and MMP-9 and it was able to inhibit transendothelial migration of MDA-MB-231 cells at all concentrations (10, 40, 100 and 1000 nM). In conclusion, ALT-C affects the extracellular matrix remodeling by modulating the activity of MMPs and expression of angiogenic genes essential for tumor growth as well as decreased cell migration. / As metaloproteinases de matriz (MMPs) são fatores chave na progressão tumoral, pois participam do remodelamento da matriz extracelular (ECM), liberam citocinas, fatores de crescimento e são reguladas por moléculas da superfície celular (integrinas). As integrinas são os principais receptores de adesão da superfície celular. Elas interagem com proteínas presentes na matriz extracelular conectando as células ao meio no qual estão inseridas possibilitando sua locomoção e a participação em cascatas de sinalização que influenciam a adesão, sobrevivência e a proliferação celular. Importantes inibidores dessas moléculas foram encontrados em venenos de serpentes denominados de desintegrinas. Alternagina-C (ALT-C), uma desintegrina de veneno da serpente Rhinocerophis alternatus, tem afinidade para a integrina &#945;2&#946;1, modula a adesão, migração e a proliferação celular mas não há nenhum estudo publicado sobre sua influência na atividade das MMPs. Nesse estudo, a ALT-C foi capaz de aumentar a migração celular em MDA-MB-231 em baixa concentração (10 nM) e diminuir a migração em concentrações mais elevadas (40, 100 e 1000 nM). ALT-C também inibiu a atividade de MMP-9 em meio condicionado de células de carcinoma de mama (MDAMB- 231) e atividade de MMP-2 em meio condicionado de fibroblastos e células endoteliais microvasculares humanas (HMEC-1). A desintegrina também foi capaz de modular a expressão de genes angiogênicos como VEGF, c-MYC, MMP-2 e MMP-9 e inibir a transmigração das células tumorais através das células endoteliais. Conclui-se que a ALT-C atua no remodelamento da matriz extracelular do microambiente tumoral por modular a atividade de MMPs e a expressão de genes angiogênicos essenciais no crescimento tumoral, bem como diminuindo a migração celular.

Le photo-vieillissement cutané est en partie dû aux effets néfastes des rayonnements UV qui induisent un stress oxydant. Celui-ci joue un rôle promoteur dans l’installation d’un statut micro-inflammatoire lié à la production de médiateurs tels que des cytokines pro-inflammatoires, des métalloprotéinases de la matrice extracellulaire (MMPs) et des prostaglandines E2. Mes travaux ont été effectués sur le kératinocyte, cellule majeure de l’épiderme et acteur du processus de vieillissement cutané. Dans une première partie, nous décrivons différentes expériences menées pour évaluer l’association de plusieurs molécules anti-oxydantes connues afin d’en potentialiser l’activité. Cette étude a mis en évidence que dans certains cas, un effet pro-oxydant pouvait être observé. Dans une seconde partie, grâce à un système de multiplexing, nous avons pu identifier 39 cytokines et 4 MMPs sécrétées par les kératinocytes suites à une irradiation par des UVB. Nous avons également pu mettre en évidence une différence entre donneurs jeunes et âgés, avec une augmentation des cytokines pro-inflammatoires et une diminution des cytokines anti-inflammatoires pour ces derniers. Dans une dernière partie, l’activité d’un extrait de fleurs de Butea monosperma a été étudiée. L’extrait présente une activité anti-oxydante en piégeant les EORs intracellulaires, anti-inflammatoire en diminuant la sécrétion de cytokines pro-inflammatoires (IL-1; IL-6 et IL-8) et protectrice du derme en inhibant la production de MMP-1 ; 2 ; 9 et 10. Cette étude multifactorielle a permis d’expliquer les utilisations traditionnelles de cette plante comme anti-inflammatoire. En conclusion, afin de comprendre et de limiter les effets des radiations UVB sur le vieillissement cutané, il est nécessaire d’avoir une approche multifactorielle. Comme nous l’avons observé, le stress oxydant n’est pas le seul responsable du statut micro-inflammatoire cutané mais en est le promoteur. Il faut donc agir en amont en limitant la production d’EORs et en aval en contrôlant la sécrétion de cytokines pro-inflammatoires et de MMPs. / Early signs of skin aging are related amongst others by UV irradiation that induces an oxidative stress. This one is associated with a skin micro-inflammatory status which is the consequence of mediator productions as pro-inflammatory cytokines, matrix metalloproteinases (MMPs) and prostaglandin E2. Studies reported in this thesis were mainly conducted with human keratinocyte, one of the cells involved in the skin aging process. In a first part, we describe various experiments led to evaluate the association of several antioxydant molecules in the aim to increase their activities. This study has shown that in certain cases, a pro-oxidizing effect could be observed. In a second part, through a multiplexing system, we have identified 39 cytokines and 4 extracellular MMPs that are secreted upon UVB irradiation. We have also found a difference between the cytokines secreted by keratinocytes from young and old donors; the latter has an increase of pro-inflammatory cytokines and a decrease in anti-inflammatory cytokines. Finally, in a last part, an extract of flowers of Butea monosperma has been studied. The extract present an anti-oxidant activity by scavenging intracellular ROS, an anti-inflammatory effect by reducing the secretion of pro-inflammatory cytokines (IL-1 , IL-6 and IL-8) and a protective effect of the dermis by inhibiting the production of extracellular MMP-1, 2, 9 and 10. These results explain the strong protective anti-inflammatory activity of this plant which is widely used. In conclusion, in order to understand and limit the impact UVB radiations on skin aging, it is necessary to have a multifactorial approach. As we have observed, oxidative stress is not solely responsible for the micro-inflammatory status associated with photo-aging, but is the proponent. We must act upstream by limiting production of ROS and downstream by controlling the secretion of pro-inflammatory cytokines and MMPs.

A causa de morte da maioria das pacientes com câncer de mama se deve à doença metastática desenvolvida a partir do tumor primário. A degradação dos componentes da matriz extracelular (MEC), um dos principais eventos do processo metastático, é regulada pelo balanço entre as atividades das metaloproteinases de matriz (MMPs) e dos seus inibidores, tanto os inibidores teciduais (TIMPs) como o inibidor associado à membrana (RECK). Contudo, ainda existe pouca informação sobre os mecanismos moleculares responsáveis pela manutenção deste balanço. No presente trabalho, foi investigado o envolvimento de TGF-&#946;1 (Transforming Growth Factor-&#946;1), uma citocina multifuncional é capaz tanto de inibir o crescimento celular, quanto de promover invasão e metástase, dependendo do estadiamento e do tipo de tumor, na regulação da expressão de MMPs, TIMPs e RECK, em modelo de câncer de mama. Primeiramente, examinou-se os níveis de expressão de mRNA das isoformas e receptores de TGF-&#946;, em um painel de cinco linhagens de carcinoma mamário humano, com diferentes potenciais invasivos e metastáticos, por qRT-PCR. Os resultados obtidos demonstraram uma correlação positiva entre a expressão dessas moléculas, e a progressão do caráter invasivo e metastático celular. Em seguida, a linhagem altamente invasiva, MDA-MB-231, foi tratada com diferentes concentrações de TGF-&#946;1 recombinante. Esta citocina foi capaz de modular a expressão gênica de MMPs (MMP-2 e MMP-9) e de seus inibidores (TIMP- 2 e RECK). Tanto ERK½, quanto p38MAPK mostraram-se envolvidas neste mecanismo. Foi demonstrado que a inibição da atividade de ERK½ alterou a expressão das proteínas MMP-9, TIMP-2 e RECK, enquanto o bloqueio de p38 MAPK afetou os níveis protéicos de MMP-2 e TIMP-2. O aumento do potencial migratório e invasivo da linhagem MDA-MB-231, induzido por TGF-&#946;1, mostrou-se também dependente da atividade de MMPs, ERK½ e p38MAPK. Dada a ausência de informações sobre o papel de RECK em modelo mamário, a função deste inibidor de MMPs também foi investigada. Primeiramente, analisou-se a expressão de RECK ao longo do desenvolvimento da mama e, posteriormente, em 1040 amostras tumorais de mama humana, através da metodologia de Tissue Microarray, tendo sido possível demonstrar que a alta expressão de RECK associa-se a menor tempo de sobrevida global e livre de doença em 10 anos. Os resultados obtidos indicaram que a expressão da proteína RECK, em oposição ao verificado em outros tipos de tumores, está relacionada ao fenótipo mais agressivo de tumores de mama. Entretanto, a análise funcional de RECK, realizada por meio da utilização de vetores shRNA específicos para a inibição desta proteína, demonstrou que RECK também atua como um inibidor de invasão celular e da expressão de MMP-9, na linhagem MDA-MB-231. Em conjunto, os resultados obtidos neste trabalho contribuíram para a elucidação dos mecanismos moleculares de regulação de RECK, por clássicas moléculas associadas ao processo de tumorigênese (TGF-&#946;1 e MAPKs), bem como para o esclarecimento de suas funções em modelo mamário, sugerindo-o como mais um promissor candidato a marcador prognóstico e alvo molecular para a terapia do câncer de mama. / The metastatic disease is the main mortality cause of breast cancer patients. The metastatic process involves a complex cascade of events, including the organized breakdown of the extracellular matrix (ECM) compounds. The degradation of ECM is tightly regulated by the balance between the activities of matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors (TIMPs) and the membrane-associated inhibitor (RECK). Among the several molecules released and activated by ECM remodeling, TGF-&#946;1 (Transforming Growth Factor-&#946;1) is a multifunctional cytokine able to regulate both cell growth inhibition and invasion and metastasis promotion, depending on the tumor stage and type. Since the molecular mechanisms involved in the ECM remodeling control are still not completed understood, in this study, we investigated the involvement of TGF-&#946;1 in regulating of MMPs, TIMPs and RECK expression, in the breast cancer model. By qRT-PCR, we first examined the gene expression levels of TGF-&#946; isoforms and receptors, in a panel of five human breast cancer cell lines displaying different degrees of invasiveness and metastatic potential. Our results suggest a positive correlation between the mRNA expression of these molecules and the breast cancer progression. Moreover, the highly invasive breast cancer cell line MDA-MB-231 was treated with different concentrations of recombinant TGF-&#946;1. We described that this cytokine was able to modulate the gene expression of MMPs (MMP-2 and MMP-9) and MMPs inhibitors (TIMP-2 and RECK) at both the mRNA and protein levels, with ERK½ and p38 MAPK being involved in this molecular mechanism. However, while ERK½ activity inhibition altered MMP-9, TIMP-2 and RECK expression, the p38 MAPK blockage affected the protein levels of MMP-2 and TIMP-2. Finally, we reposted that the TGF-&#946;1-enhanced migration and invasion capacities of MDA-MB- 231 cells were blocked by MMPs, ERK½ and p38 MAPK inhibitors. Analysis of the RECK function in the breast model was also an objective of this study. We analyzed RECK expression during mammary gland development. We evaluated the RECK protein profile in 1040 breast tumor tissue samples using Tissue Microarray assays. We demonstrated that high expression levels of RECK were associated with shorter overall and disease-free survival in 10 years. Moreover, we verified that RECK is a biomarker of poor prognosis mainly for patients diagnosed with less aggressive breast tumor. Therefore, in contrast to other tumor types, our results indicate that high protein expression levels of RECK are related to a more aggressive phenotype. In fact, the RECK functional analysis, performed by using of shRNA vectors, showed that RECK function remains as an inhibitor of cellular invasion and MMP-9 expression, in MDA-MB-231 cells. Taken together, our results contribute to better understanding of the molecular mechanisms associated to RECK regulation by TGF-&#946;1 and MAPK as well as to clarify its role in breast model. Thus, we suggests RECK as a new and promising prognostic marker and molecular target candidate for breast cancer therapy.