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Le TIMP-1, inhibiteur naturel des métalloprotéinases matricielles, exerce des effets pléïotropes indépendants de l'inhibition des MMPs et participe au développement de certains cancers et maladies neurodégénératives. Ces effets cytokiniques du TIMP-1 impliquent sa liaison à des récepteurs membranaires dont certains sont caractérisés, la glycoprotéine CD63/intégrine beta 1 et le complexe pro MMP-9/CD44. Cependant les acides aminés ou les domaines du TIMP-1 se liant à ces récepteurs ne sont pas identifiés. Les travaux réalisés au cours de cette thèse mettent en évidence un nouveau récepteur du TIMP-1, la protéine LRP-1. Dans les neurones corticaux murins, le TIMP-1 se fixe aux domaines DII et DIV de LRP-1, est endocyté et induit une réduction de la taille des neurites ainsi qu'une augmentation du volume des cônes de croissance. Afin de caractériser cette interaction, nous avons utilisé une approche originale de modélisation moléculaire associant les analyses de modes normaux et la dynamique moléculaire. Ces analyses in silico ont permis d'identifier un mouvement de pince entre les domaines N et C-terminaux du TIMP-1. Nous avons muté trois résidus (F12, K47 et W105) localisés dans une région essentielle d'un point vue énergétique à l'exécution de ce mouvement. Ces trois mutants n'ont pas d'effet sur la longueur du réseau neuritique et ne sont pas endocytés par LRP-1. En revanche, ils interagissent avec les 2 autres récepteurs (CD63 et proMMP-9) et reproduisent les effets du TIMP-1 sauvage. De plus, nous avons identifié une séquence de 6 acides aminés localisée dans le domaine extracellulaire I de CD63 et essentielle à la liaison avec le TIMP-1. L'ensemble de ces travaux a permis l'identification de régions impliquées dans l'interaction du TIMP-1 avec ses différents récepteurs et pourrait permettre le développement de nouveaux outils pharmacologiques ciblant les activités cytokiniques du TIMP-1. / TIMP-1, a natural inhibitor of matrix metalloproteinases, exerts pleiotropic effects independent of MMP inhibition and thus participates to the development of some cancers and neurodegenerative disorders. These cytokine-like activities require TIMP-1 binding to membrane receptors. Up to date two receptors, CD63/integrin beta 1 and proMMP-9/CD44, have been characterized. Nevertheless, TIMP-1 residues or regions binding these receptors remain unknown. In this work, we have identified the protein LRP-1 as a new receptor for TIMP 1. In mouse cortical neurons, TIMP-1 preferentially binds DII and DIV domains of LRP-1, is internalized via a LRP-1-dependent endocytosis, reduces neurite length and increases growth cone volume. To go deeper into TIMP-1/LRP-1 interaction, we used an original molecular modeling approach which combined normal mode analysis and molecular dynamic. These in silico studies allow us to point out a clamp movement between the N- and C-terminal domains of TIMP-1. Three residues localized in a region that seems essential for the movement have been mutated (F12, K47 and W105) and single mutants have been produced. These mutants do not reduce neurite outgrowth and are not internalized by LRP-1. In contrast, they interact with the two others receptors proMMP-9 and CD63 and induce associated biological effects. Furthermore, we have identified a sequence of six residues localized in the CD63 extracellular domain I and essential for TIMP 1 binding. The set of our data highlighted new regions of TIMP-1 interacting with its receptors and could lead to design novel therapeutic agents targeting the TIMP-1 cytokine like activities.

Made available in DSpace on 2014-07-29T15:07:41Z (GMT). No. of bitstreams: 1 Dissertacao_Denise C Toledo.pdf: 1395118 bytes, checksum: 592dff1a4d2ff80089be7e8691c93893 (MD5) Previous issue date: 2012-03-08 / The canine gland has drawn interest for research due to its similarities with the human prostate and the great incidence of lesions. Moreover, the canine prostate shows high incidence of diseases. The main lesions that affect the prostate are prostatitis, benign prostatic hyperplasia (BPH), cysts and adenocarcinoma. Recently attention has been given to lesions considered premalignant such as prostatic intraepithelial neoplasia (PIN) and proliferative inflammatory atrophy (PIA), both studied in the human gland and also found in the canine prostate. In order to evaluate the development of prostate cancer starting as premalignant lesions, some immunohistochemical markers are employed, such as tissue inhibitors of metalloproteinases (TIMP), which have a key role in regulating the catalytic action of metalloproteinases (MMP), and transforming growth factor-β (TGF-β), that induces angiogenesis and inhibits cell proliferation and is considered a mediator of prostate growth. The objective of this study was to investigate the expression of TIMP-1, TIMP-2 and TGF-β in canine normal prostate tissue and with proliferative lesions. For this, 150 adult canine prostates were obtained from postmortem examinations. After microscopic evaluation 54 glands, compatible with normal, epithelial BPH, stromal BPH, PIA, PIN and adenocarcinoma were selected and used to make tissue microarray block (Tissue Microarray - TMA). TMA slides were subjected to immunohistochemistry with anti-TIMP-1, anti-TIMP-2 and anti-TGF-β, to assess staining intensity of epithelial cells and stromal cells.Cytoplasmatic staining of canine prostate cells by TIMP-1, TIMP-2 and TGF-β was observed, with TIMP-1 and TIMP-2 being more expressed in premalignant and malignant lesions, while TGF-β was expressed mainly by normal tissue and BPH. Furthermore, there were differences in the expression between epithelial and stromal cells. / A próstata canina, além das similaridades com a próstata humana, apresenta grande incidência de afecções. As principais lesões que acometem a próstata são as prostatites, a hiperplasia prostática benigna (HPB), os cistos e o adenocarcinoma, sendo que, recentemente, se tem dado atenção às lesões consideradas pré-malignas, como a neoplasia intraepitelial prostática (PIN) e a atrofia inflamatória proliferativa (PIA), ambas estudadas na glândula humana, e também verificadas na próstata do cão. Para avaliar o desenvolvimento de neoplasias prostáticas a partir das lesões pré-malignas, alguns marcadores imunoistoquímicos são empregados, como os inibidores teciduais de metaloproteinases (TIMP), que apresentam importante função na regulação da ação catalítica das metaloproteinases (MMP), e o fator de crescimento transformador β (TGF-β), que induz a angiogênese e inibe a proliferação celular, sendo considerado um mediador do crescimento prostático. O objetivo deste estudo foi verificar a expressão de TIMP-1, TIMP-2 e TGF-β no tecido prostático canino normal e com lesões proliferativas. Para isso foram colhidas, em exames necroscópicos, 150 próstatas de cães adultos e idosos. O material foi avaliado histologicamente e selecionadas amostras de 54 próstatas com predominância de histomorfologia normal, HPB epitelial, HPB estromal, PIA, PIN e adenocarcinoma, que foram utilizadas para a confecção de um bloco de microarranjo tecidual (Tissue Microarray - TMA). As lâminas de TMA foram submetidas à imunoistoquímica com os anticorpos anti-TIMP-1, anti-TIMP-2 e anti-TGF-β, sendo avaliada a intensidade de marcação das células epiteliais e estromais. Verificou-se que há marcação citoplasmática das células prostáticas caninas para TIMP-1, TIMP-2 e TGF-β, sendo as proteínas TIMP-1 e TIMP-2 mais expressas nas lesões proliferativas pré-malignas e malignas, enquanto TGF-β foi expresso principalmente pelo tecido normal e com HPB epitelial e estromal. Ainda, houve diferença de marcação entre células epiteliais e estromais.

This dissertation elucidates several independent molecular mechanisms that function in astrocytes and glial tumor cells, and suggest that developmental and inflammatory signals may contribute to the development of brain tumors. First, we analyzed the mechanism of TIMP-1 activation in astrocytes and glioblastoma cells. TIMP-1 expression is activated by IL-1, which is the major neuroinflammatory cytokine, via simultaneous activation of IKK/NF-kB and MEK3/6/p38/ATF-2 pathways in primary human astrocytes. In contrast to astrocytes, TIMP-1 is expressed at lower levels in glioblastomas, and is not regulated by IL-1 due to either dysfunctional IKK/NF-kB or MEK3/6/p38/ATF-2 activation. Thus, we propose a novel mechanism of TIMP-1 regulation, which ensures an increased supply of the inhibitor after tissue injury to limit the ECM degradation. This mechanism does not operate in gliomas, and may in part explain the increased invasiveness of glioma cells.Inflammation has been associated with the development of several cancers, including glioblastoma multiforme. However, it has not been linked to other brain tumors. Here we show for the first time that inflammation is associated with oligodendroglioma tumors as pro-inflammatory cytokines, such as OSM, IL-6, MCP1, MIP1α, and MIP1β and inflammatory markers, such as ACT and COX-2, were expressed at higher levels in oligodendroglioma samples. In addition, cytokine-induced STAT3 signaling, but not NF-kB, is highly activated in the oligodendroglioma patients. Moreover, OSM promotes oligodendroglioma cell proliferation in vitro, and this effect is mediated through STAT3. In summary, oligodendroglioma tumors secrete and respond to inflammatory mediators, with OSM being the major cytokine that activates STAT3 to promote the growth of tumor cells, and express ACT and COX-2 as a hallmark of ongoing inflammation. Since STAT3 promotes the growth of oligodendroglioma, as well as glioblastoma cells, and also regulates gliogenesis, we studied molecular mechanisms of this process in an in vitro differentiation model. We turn our attention to the NFI family of transcription factors since they have recently emerged as novel regulators of the development of vertebral neocortex. We developed a stem cell-neural progenitor-astrocyte differentiation model, in which the generated astrocytes were characterized by proper morphology, increased glutamate uptake, and expression of early and late astrocyte markers. Moreover, we found that NFI-X and NFI-C but not NFI-A or NFI-B, control the expression of GFAP and SPARCL1, the markers of terminal differentiation of astrocytes.In summary, the three mechanisms of gene regulation we studied, provided new insights into astrocyte biology, with the important implications for understanding the basis leading to the development and progression of brain tumors.

Η HARP (Heparin Affin Regulatory Peptide) είναι ένας αυξητικός παράγοντας με Μ.Β. 18 kDa που ανήκει στην οικογένεια των αυξητικών παραγόντων που έχουν συγγένεια με την ηπαρίνη. Eμπλέκεται στην ανάπτυξη των νευριτών, την επούλωση πληγών και φαίνεται να παίζει σημαντικό επαγωγικό ρόλο στις διαδικασίες της ογκογένεσης, καθώς επάγει την αγγειογένεση και εμφανίζεται σε υψηλές συγκεντρώσεις τόσο σε καρκινικούς ιστούς, όσο και σε κυτταρικές σειρές καρκινικών κυττάρων. Στο πλαίσιο μελέτης της σχέσης δομής/δράσης του αυξητικού αυτού παράγοντα, χρησιμοποιούνται τόσο συνθετικά πεπτίδια, όσο και ανασυνδυασμένες τροποποιημένες μορφές του αυξητικού αυτού παράγοντα. Σε φυσιολογικές συνθήκες, η εκκρινόμμενη HARP πέπτεται από ένζυμα του κυτταρικού μικροπεριβάλλοντος και προκύπτουν πεπτίδια που παρουσιάζουν βιολογικές δράσεις παρόμοιες ή και αντίθετες από αυτές της HARP. Φαίνεται λοιπόν πως η δράση του αυξητικού αυτού παράγοντα ρυθμίζεται τόσο στο επίπεδο βιοσύνθεσης και έκκρισης, όσο και από τη δράση ενζύμων του εξωκυττάριου χώρου. Στην παρούσα εργασία μελετήθηκε η δράση ενός συνθετικού πεπτιδίου το οποίο αντιστοιχεί στα αμινοξέα 65-97 που εντοπίζονται στην ΤSR περιοχή προς το καρβοξυτελικό άκρο της HARP. Με δεδομένο ότι τι πεπτίδιο αυτό εμφανίζει αντιαγγειογενετική δράση, πραγματοποιήθηκαν χρονοεξαρτώμενα και δοσοεξαρτώμενα πειράματα, με σκοπό τη μελέτη της δράσης του στον πολλαπλασιασμό, τη μετανάστευση και την επούλωση πληγών. Στο πλαίσιο αυτών των μελετών, ελέγξαμε τη δράση του στην έκφραση των μεταλλοπρωτεϊνασών ΜΜP-2 και ΜΜP-9, των αναστολέων τους ΤΙMP-1 και ΤΙMP-2 καθώς και του κολλαγόνου και της ελαστίνης σε πρωτογενείς καλλιέργειες ενδοθηλιακών κυττάρων από ομφάλιο λώρο (HUVEC cells). Τα αποτελέσματα έδειξαν πως το συνθετικό αυτό πεπτίδιο καταστέλλει τον πολλαπλασιασμό, την μετανάστευση αλλά και την επούλωση πλήγών των κυττάρων HUVEC με δοδοεξαρτώμενο και στατιστικώς σημαντικό τρόπο. Επιπλέον από τα πειράματά μας δεν παρατηρήθηκε μεταβολή στα πρωτεϊνικά επίπεδα έκφρασης των μεταλλοπρωτεϊνασών ΜΜP-2 και ΜΜP-9 καθώς και των αναστολέων τους ΤΙMP-1 και ΤΙMP-2. Ωστόσο, παρατηρήθηκε στατιστικώς σημαντική μεταβολή στα επίπεδα γονιδιακής έκφρασης των αναστολέων ΤΙMP-1 και ΤΙMP-2 όπως επίσης και της ελαστίνης και του κολλαγόνου IV. / Heparin affin regulatory peptide (HARP) is an 18-kDa secreted growth factor that has a high affinity for heparin and a potent role on tumor growth and angiogenesis. HARP was originally described as a neurite outgrowth promoting molecule, which appears to increases during recovery from injury and is thought to be involved in angiogenesis expression, playing a major role in the cell growth and differentiation that are associated with regeneration in several tissues. HARP is expressed in several human tumors and tumor cell lines and is also indicated in high serum levels of patients with different types of cancer. HARP contains two random coiled clusters of basic residues (N- and C-terminal) and two b-sheet domain. Each b-sheet domain contains a thrombospondin repeat I (TSR-I) motif, which have been suggested to be responsible for the interaction of HARP with heparin. Our project is based on C-TSR-I domain, corresponding to amino acids 65–97 of HARP peptide, respectively, required for the neurite outgrowth activity of HARP. In this study, we investigate the impact of C-TSR on basic biological functions of endothelial cells (HUVEC) such as proliferation, migration, the expression of MMP-2 and MMP-9 and their inhibitors (TIMP-1, TIMP-2) that contribute to the ECM remodeling. Time course and dose-response experiments revealed that CTSR reduces proliferation, migration and wound healing, without affecting the protein levels of MMP-2 and MMP-9 and their inhibitors (TIMP-1, TIMP-2). Moreover, CTSR inhibits the expression of TIMP-1 and TIMP-2 contributing to the ECM remodeling. Concluding, HARP could act as pro- or anti-angiogenic factor, depending on the system used and the cell microenvironment.

Abstract Breast carcinoma is a heterogeneous disease with a prognosis that varies from excellent to very poor. Traditional tumour parameters and biological factors that are also predictive for treatment response are used in determining breast carcinoma prognosis and selecting appropriate treatment. Gelatinases MMP-2 and MMP-9 have been shown to associate with tumour progression. Their tissue inhibitors TIMP-1 and -2 are multifunctional molecules that have been suggested as prognostic markers in some previous reports. In the present work, the expression and prognostic value of gelatinases MMP-2 and MMP-9 and their tissue inhibitors TIMP-1 and -2 were assessed in primary breast carcinoma. The material consisted of a total of 416 patients. Tissue expression of TIMP-1 and -2 was analysed in a population of 203 patients using immunohistochemistry. Circulating gelatinases and their inhibitors were studied using ELISA in two different populations of 71 at preoperative state and 213 patients at pre- and postoperative state. High expression of TIMP-1 immunoreactive protein positively correlated with high histological grade of the tumour and associated with aggressive disease course in grade 2–3 subpopulation. High preoperative plasma TIMP-1 was prognostic for relapse in a modern patient series after a median follow-up time of 18 months. TIMP-1 as a continuous variable was prognostic in Cox regression univariate analysis, and was an independent prognostic variable superior to nodal status in multivariate analysis. High preoperative serum TIMP-1 was an independent prognostic variable for poor disease-specific survival, and TIMP-1 was found to maintain its prognostic value when assessed independently with different ELISA analyses, and was not very sensitive for preanalytical conditions. In addition, low circulating preoperative serum MMP-2 was observed to associate with high stage and positive nodal status in breast carcinoma. These results indicate that circulating TIMP-1 may be a potential new marker of worsened prognosis in breast carcinoma, although careful validation of assay platforms and identification of the sources of physiological variation are needed before it can be adopted into clinical decision-making.

Abstract Mammalian extracellular matrix metalloproteinases, MMPs, are a family of enzymes capable of degrading components of the connective tissue. The in vivo regulation of the cell lineage-specific expression of MMPs, however, is not well known. This study used transgenic mice to identify cell-specific elements in the upstream regulatory regions of MMP-2 and MMP-9. Transgenic mice were generated by pronuclear microinjections into fertilised oocytes using lacZ as a reporter gene. The reporter gene constructs containing varying lengths of the MMP-9 5'-upstream region revealed an area that allowed for expression in osteoclasts and migrating keratinocytes, the cells that also express MMP-9 in vivo. The sequence driving the cell specific expression included the nucleotides from -2722 to -7745. When the same upstream regulatory fragment of MMP-9 was used to drive the expression of the human tissue specific inhibitor of MMPs, TIMP-1, instead of lacZ, the transgenic mice developed normally and the animals were fertile with normal post-embryonic growth. However, cutaneous wound healing was remarkably retarded, but not totally prevented, and the migration of keratinocytes over the wound was slow. The mice expressed the human TIMP-1 in keratinocytes during wound healing and in situ zymography revealed a total blockage of the gelatinolytic activity of MMP-2 and MMP-9, the main gelatinases active in the healing wound tissues. By using a sequence of 6500 base pairs from the 5'-upstream regulatory region of the MMP-2 gene it was possible to drive the expression of lacZ in mesenchymal cells of the developing transgenic mouse embryo. The expression pattern was similar to that found in previous in situ hybridization studies, following the different stages of tissue morphogenesis and being present in the areas of basement membrane degradation and epithelial cell invasion. Computer analyses of the sequence revealed three regulatory upstream regions conserved between human, mouse, and rat, and possibly responsible for the cell-and tissue specificity. New transgene constructs containing fragments of the conserved regions will provide a more detailed profile of the in vivo MMP-2 regulation in the future. This study defined a fragment in the upstream regulatory region of MMP-9 that is essential for expression in osteoclasts and migrating keratinocytes. Furthermore, the keratinocyte derived MMPs, including MMP-9, were found to play important role in epithelial cell migration in the area of the healing wound.

We previously demonstrated that embryonic stem (ES) cells over-expressing tissue inhibitor of metalloproteinase-1 (TIMP-1) have increased potential to engraft and differentiate into cardiac myocytes following transplantation into the infarcted heart. However, the ability of TIMP-1 to activate endogenous stem cells and enhance their differentiation into cardiac regenerative cell types is still unknown. We postulate that TIMP-1 may additionally activate a stem cell population that enhances cardiac cell type differentiation in the infarcted myocardium. To prove this hypothesis, we isolated c-kit+ve cells from four weeks old C57BL/6 mice and cultured them in vitro in presence of ES conditioned media (ESCM), ES-TIMP-1-CM or TIMP-1. Our immunostaining data validate the existence of a novel CD63+ve/c-kit+ve cells. When treated with TIMP-1, these cells showed significantly (p < 0.05) increased proliferation and differentiation into cardiac myocytes, vascular smooth muscle cells, and endothelial cells. Western blot analysis revealed significantly (p < 0.05) increased expression of CD63, phosphorylated and total β-catenin proteins. Furthermore, our RT-PCR data showed increased cardiac gene expression (GATA-4, Mef2C, and Nkx-2.5) when compared to ESCM and control cells. Based on the in vitro findings, we investigated the effect of intramyocardial delivery of TIMP-1 on endogenous CD63+ve/c-kit+ve cells following myocardial infarction (MI). C57BL/6 and TIMP-1 KO mice underwent coronary artery ligation followed by intramyocardial delivery of 20μl of culture media (CC), ESCM, ES-TIMP-1-CM or TIMP-1. Subsequent immunohistochemistry analysis demonstrated the presence of a CD63+ve/c-kit+ve cell population within the peri-infarct area and confirmed intramyocardial delivery of ES-TIMP-1-CM or TIMP-1 significantly (p < 0.05) enhanced their proliferation. Percentage of CD63+ve/c-kit+ve cells was significantly (p < 0.05) lower in TIMP-1 KO mice compared to C57BL/6 animals. RT-PCR analysis revealed TIMP-1 KO animals expressed significantly less CD63 and TIMP-1 mRNAs compared to C57BL/6 mice. Activated CD63+ve/c-kit+ve cells were also able to differentiate into major cardiac cell types as previously shown in vitro. The differentiation potential of these cells was however higher in C57BL/6 mice compared to TIMP-1 KO mice. We also demonstrate that CD63+ve/c-kit+ve cells differentiation is regulated by CD63/β-catenin pathway in vivo. Additionally, we provide evidence that TIMP-1 protects the heart from adverse cardiac remodeling through inhibition of cardiac apoptosis and fibrosis leading to significantly (p < 0.05) improved contractile function. Collectively, our data show TIMP-1 plays a dual protective role in the MI heart. It activates a unique stem cell population, CD63+ve/c-kit+ve, which proliferates and differentiates into functional myocytes, smooth muscle cells and endothelial cells mediated through CD63/β-catenin pathway. TIMP-1 also protects the heart from adverse cardiac remodeling. Increased cardiac regeneration and inhibition of adverse cardiac remodeling consequently lead to restored cardiac function.

<p>Migration of T-lymphocytes on a surface coated with extracellular matrix (ECM) components (two-dimensional (2-D) migration) and migration (infiltration) into a matrix (Three-dimesional (3-D) migration) are complex events and the underlying mechanisms are not yet fully understood. Here 2-D and 3-D migration were studied by use of seven leukemic T-cell lines representing discrete differentiation stages, a non-leukemic T-cell clone, and normal peripheral blood T cells. peripheral blood lymphocytes and the T-cell clone produced nanogram quantities of various chemokines, as compared to a production of ≤ 0.05 ng/ml by the T leukemia cell lines. In a Boyden chamber system, the leukemic T-cell lines showed haptotactic migration on fibronectin. The migration was augmented bu exposure to chemokines, including RANTES, MIP-1α, MIP-1β, and IL-8. The T-cell lines showed a peak response at a chemokine concentration of 10-50 ng/ml, whereas the T-cell clone responded optimally at 100 ng/ml. In contrast to a general capability of T-cells to migrate on 2-D ECM, only some of the T-cell lines were capable of 3-D migration into Matrigel or a collagen matrix. The infiltrative capacity was unrelated to the capacity to migrate on or adhere to the substrata. T-cell lines with a capacity to infiltrate produced matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), whereas non-infiltrating cell lines did not produce MMP-9. T-cell lines capable of infiltrating Matrigel or collagen responded to chemokines exposure with increased infiltration, but the chemokines did not render non-infiltrative cell lines infiltrative. Stimulation of infiltration of T-cell lines into collagen by the chemokine SDF-1α was inhibited by somatostatin, a neuropeptide with immunosuppressive properties. In conclusion, the ability to migrate on 2-D substrata and to infiltrate into 3.D substrata was found to be distinguishable properties of T cells. failure of some T-cell lines to infiltrate correlated with the lack of expression of MMP-9. Chemokines stimulated infiltration of infiltrative T-cell lines into collagen and Matrigel but did not render non-infiltrative T-cell lines infiltrative. Finally, a possible physiological mechanism for modulation of the chemokine-stimulated 3-D migration was demonstrated.</p>

Migration of T-lymphocytes on a surface coated with extracellular matrix (ECM) components (two-dimensional (2-D) migration) and migration (infiltration) into a matrix (Three-dimesional (3-D) migration) are complex events and the underlying mechanisms are not yet fully understood. Here 2-D and 3-D migration were studied by use of seven leukemic T-cell lines representing discrete differentiation stages, a non-leukemic T-cell clone, and normal peripheral blood T cells. peripheral blood lymphocytes and the T-cell clone produced nanogram quantities of various chemokines, as compared to a production of ≤ 0.05 ng/ml by the T leukemia cell lines. In a Boyden chamber system, the leukemic T-cell lines showed haptotactic migration on fibronectin. The migration was augmented bu exposure to chemokines, including RANTES, MIP-1α, MIP-1β, and IL-8. The T-cell lines showed a peak response at a chemokine concentration of 10-50 ng/ml, whereas the T-cell clone responded optimally at 100 ng/ml. In contrast to a general capability of T-cells to migrate on 2-D ECM, only some of the T-cell lines were capable of 3-D migration into Matrigel or a collagen matrix. The infiltrative capacity was unrelated to the capacity to migrate on or adhere to the substrata. T-cell lines with a capacity to infiltrate produced matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), whereas non-infiltrating cell lines did not produce MMP-9. T-cell lines capable of infiltrating Matrigel or collagen responded to chemokines exposure with increased infiltration, but the chemokines did not render non-infiltrative cell lines infiltrative. Stimulation of infiltration of T-cell lines into collagen by the chemokine SDF-1α was inhibited by somatostatin, a neuropeptide with immunosuppressive properties. In conclusion, the ability to migrate on 2-D substrata and to infiltrate into 3.D substrata was found to be distinguishable properties of T cells. failure of some T-cell lines to infiltrate correlated with the lack of expression of MMP-9. Chemokines stimulated infiltration of infiltrative T-cell lines into collagen and Matrigel but did not render non-infiltrative T-cell lines infiltrative. Finally, a possible physiological mechanism for modulation of the chemokine-stimulated 3-D migration was demonstrated.