Orientador: Cecilia Amelia Fazzio Escanhoela / Dissertação (mestrado) - Universidade Estadual de Campínas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-15T12:26:43Z (GMT). No. of bitstreams: 1 Segatelli_Vanderlei_M.pdf: 1173808 bytes, checksum: efbd82ac6962165e42a166dfef483327 (MD5) Previous issue date: 2010 / Resumo: O carcinoma hepatocelular (CHC) destaca-se como uma das formas mais comuns de câncer no mundo, correspondendo a aproximadamente 90% das neoplasias primárias do fígado, sendo a cirrose seu mais importante fator de risco. A sua progressão, no entanto, depende de inúmeros fatores e, entre estes, a angiogênese assume papel fundamental, principalmente por ser o CHC um tumor altamente vascularizado. É sabido que tumores sólidos, ao atingirem volume de 1 a 2mm3, passam a ter seu crescimento dependente de neovascularização e no fígado esta se faz através de capilarização sinusoidal, processo pelo qual ocorrem alterações morfológicas nos sinusóides hepáticos, com perda das fenestrações e deposição de membrana basal. Neste estudo retrospectivo avaliamos a angiogênese, através dos marcadores imuno-histoquímicos CD34 e CD105 (Endoglina), com determinação da densidade microvascular (DMV) em 44 produtos de hepatectomia total, compreendendo 44 nódulos neoplásicos (CHC), 44 nódulos regenerativos (NR) e 15 nódulos com características microscópicas de lesões pré-malignas (ou Nódulos Displásicos - ND), sendo 8 de baixo grau e 7 de alto grau. A avaliação compreendeu a determinação da DMV no centro e na periferia de todos os nódulos. Para análise estatística foi utilizada análise descritiva com apresentação de medidas de posição e dispersão para variáveis contínuas; para a comparação dos grupos foi utilizada a ANOVA, considerando-se p<0,05 estatisticamente significante. O CD34 demonstrou positividade difusa no CHC, com valores médios da DMV de 38,3±12,6 e 34,2±11,2 no centro e periferia, respectivamente. Já o CD105 apresentou expressão sinusoidal predominantemente periférica no CHC, com valores médios da DMV de 6,2±4,1 e 10,7±4,4, com diferenças significativas entre os grupos (p<0,0001). Também foram observadas diferenças na imunoexpressão entre os marcadores em NR (p<0,0001) e ND (p<0,0019). Concluímos que existem diferenças na imunoexpressão do CD34 e CD105 entre os nódulos benignos e malignos, com gradual aumento da neovascularização, bem caracterizado pelo CD34, devido ao processo de capilarização sinusoidal. O CD105, expresso em "subset" de microvasos neoformados, pode ser um indicador de diferenciação diagnóstica entre NR e CHC / Abstract: Hepatocellular carcinoma (HCC) is one of the most common forms of cancer worldwide, accounting for about 90% of primary tumors of the liver. Cirrhosis is the most important risk factor for HCC. However, the progression of hepatocellular carcinoma is dependent on a number of factors. Among these factors, angiogenesis plays a major role, mainly because HCC is a highly vascular tumor. It is known that when solid tumors reach a volume of 1 to 2mm3 their growth depends on neovascularization. In the liver, this occurs through sinusoidal capillarization, a process by which morphologic alterations occur in the hepatic sinusoids, with loss of fenestrations and basement membrane depositions. In this retrospective study, we evaluated angiogenesis by using immunohistochemical markers CD34 and CD105 (Endoglin), with determination of tumor microvessel density (MVD) in 44 products of total hepatectomy, including 44 malignant nodules (HCC), 44 regenerative nodules (RN) and 15 nodules with microscopic characteristics of preneoplastic lesions (or Dysplastic Nodules-DN), 8 being low-grade and 7 high-grade. The evaluation encompassed measurement of MVD in the center and periphery of all nodules. For statistical analysis, a descriptive analysis with measurements of position and dispersion for continuous variables was used. ANOVA was used for group comparison, considering p<0.05 as statistically significant. CD34 demonstrated a diffuse positivity in HCC, with median MVD values of 38.3±12.6 and 34.2±11.2 in the center and periphery, respectively. On the other hand, CD105 exhibited sinusoidal expression predominantly in the periphery of the HCC, with median MVD values of 6.2±4.1 and 10.7±4.4, with significant differences between groups (p<0.0001). Differences in the immunoexpression between markers in RN (p<0.0001) and DN (p<0.0019) were also observed. In conclusion, there are differences in the immunoexpression of CD34 and CD105 between benign and malignant nodules, with a gradual increase in neovessel formation, well-characterized by CD34, due to a process of sinusoidal capillarization. CD105, expressed in a "subset" of newly formed microvessels may be an indicator of the diagnostic differentiation between RN and HCC / Mestrado / Anatomia Patologica / Mestre em Ciências Médicas

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A talidomida, anteriormente usada para aliviar desconfortos gÃstricos da gravidez, atualmente à usada para tratamento do cÃncer e de doenÃas inflamatÃrias. VÃrios anÃlogos ftalimÃdicos da talidomida tem sido pesquisados quanto a sua atividade antiangiogÃnica e imunomodulatÃria. Em estudos prÃvios, estes anÃlogos mostraram ausÃncia de atividade imunossupressora. O trabalho determinou, inicialmente, a atividade citotÃxica, de oito anÃlogos ftalimÃdicos da talidomida, frente a linhagens tumorais e de cÃlulas mononucleadas isoladas de sangue perifÃrico (CMSP) apÃs 72h de incubaÃÃo. Nenhum dos compostos desencadeou atividade citotÃxica in vitro, induÃÃo de hemÃlise em eritrÃcitos e potencial em induzir dano à fita de DNA, portanto nÃo foram genotÃxicos em CMSP humanas. O efeito antitumoral (in vivo) da talidomida e dos oito anÃlogos foi analisado em camundongos transplantados com o tumor Sarcoma 180 e tratados na dose 50mg/Kg/7 dias, via i.p. A inibiÃÃo do crescimento tumoral foi significante apenas para talidomida (53,5%) e anÃlogos SC-10 e SC-11 (67,9% e 67,4%, respectivamente), p<0,05. A anÃlise histopatolÃgica dos ÃrgÃos dos animais mostrou que a talidomida e seus anÃlogos provocam efeitos tÃxicos moderados, principalmente no fÃgado, mas esses podem ser considerados como reversÃveis. Os estudos acerca do mecanismo de aÃÃo foram aprofundados usando cÃlulas isoladas do Sarcoma 180, apÃs 72 horas de incubaÃÃo, nas doses de 10, 50 e 100Âg/mL, por citometria de fluxo, atravÃs dos seguintes ensaios: 1- AvaliaÃÃo da integridade de membrana, viabilidade celular e concentraÃÃo de cÃlulas; 2- DeterminaÃÃo do conteÃdo de DNA nuclear da cÃlula. Todos os compostos induziram a perda de integridade de membrana celular e fragmentaÃÃo internucleossomal do DNA nas maiores concentraÃÃes, indicando presenÃa de cÃlulas apoptÃticas em estÃgios finais ou em processo de necrose secundÃria. A avaliaÃÃo do potencial antiangiogÃnico, pelo ensaio do Wound Healing revelou que para a linhagem endotelial (HUVEC) o anÃlogo SC-10 causou uma inibiÃÃo maior (65,28%  1,58), enquanto que na linhagem tumoral o efeito maior foi do anÃlogo SC-11 (98,51%  0,25). A talidomida nÃo foi capaz de reduzir a migraÃÃo celular em nenhuma das linhagens testadas. No ensaio da membrana corioalantÃide (CAM), potencial antiangiogÃnico foi observado para os anÃlogos SC-10 e SC-11(5mg/mL), que inibiram o nÃmero de vasos (12, 88%  2,3 e 14,81%  3,3), a Ãrea de neovascularizaÃÃo (13,14%  1,7 e 14,26%  1,7) e o comprimento total de vasos em mm2 (9,19%  1,5 e 9,86%  1,9). A talidomida, nÃo foi capaz de inibir a vascularizaÃÃo embrionÃria. O efeito antitumoral (in vivo) da talidomida e anÃlogos SC-10 e SC-11 foi analisado em camundongos transplantados com o tumor Sarcoma 180, tratados na dose 50mg/Kg/10 dias, via i.p. A inibiÃÃo do crescimento tumoral para a talidomida (56.6%) e para os anÃlogos SC-10 e SC-11 (48,2% e 41,3%, respectivamente), p<0,05. A imunocoloraÃÃo de cÃlulas endoteliais intratumorais com CD-31, revelou-se, na forma de densidade microvascular, diminuÃda nos grupos tratados com anÃlogos SC-10 e SC-11 (64,59% e 46,51%), mas nÃo nos grupos tratados com a talidomida. Estes resultados, unidos a estudos prÃvios de imunomudulaÃÃo sugerem imunidade antitumoral e antiangiogÃnica, dependente de cÃlulas T, para os anÃlogos ftalimÃdicos. / The thalidomide was previously used to relieve gastric discomforts during pregnancy, and currently it is used for cancer treatment and inflammatory illnesses. Various phthalimides analogues of thalidomide have been researched for its antiangiogenic and immunemodulatory activity. In previous studies, these analogues showed absence of immunesuppressor activity. In this context, this work initially determined the cytotoxic activity of eight phthalimides analogues of thalidomide, in a series of cancer cell lines and of isolated peripheral mononuclear blood cells (PMBC) after 72h of incubation. None of compounds revealed cytotoxic activity in vitro in cancer cell lines and hemolytic activity towards of PBMC. They also showed no potential damage to the DNA strand, therefore they were not considered genotoxic towards human PMBC. The antitumor effect (in vivo) of thalidomide along with eight analogues was analyzed in mice transplanted with the Sarcoma 180 tumor and treated in a dose of 50mg/Kg/7 days, i.p. The inhibition of the tumor growth was only significant in mice treated with thalidomide (53.5%) and the analogues SC-10 and SC-11 (67.9% and 67.4%, respectively), p< 0,05. The histopathological analysis of the animalsâ organs showed mainly that thalidomide and its analogues cause moderate toxic effects, mostly in the liver, but these can be considered reversible. The studies concerning the mechanism of action were deepened using isolated cells from the Sarcoma 180, after 72 hours of incubation, in the doses of 10, 50 and 100Âg/mL. The following flow cytometry assays were carried out: 1- Evaluation of the membrane integrity, cellular viability and concentration of cells; 2- Determination of the nuclear DNA content. All the compounds led to the loss of membrane cell integrity and it was found internucleossomal DNA fragmentation in the higher concentrations, indicating the presence of cells with late stage apoptotic characteristics or in the process of secondary necrosis. The evaluation of the antiangiogenic potential, with the Wound Healing assay revealed that for the endothelial cell line (HUVEC) the analogue SC-10 caused a greater inhibition (65.28%  1,58), whereas in the tumor cell line the highest effect was of the analogue SC-11 (98.51%  0,25). The thalidomide was not capable of reducing cellular migration in none of the tested cell lines. In the chorioallantoic membrane assay (CAM), an antiangiogenic potential was observed with analogous SC-10 and SC-11 (5mg/mL), where there was an inhibition in the number of vessels (12, 88%  2,3 and 14.81%  3,3), the area of neovascularization (13.14%  1,7 and 14.26%  1,7) and the total length of vessels in mm2 (9.19%  1,5 and 9.86%  1,9). The thalidomide was not capable of inhibiting embryonic vascularization. The antitumor effect (in alive) of thalidomide and the analogues SC-10 and SC-11 was analyzed in mice transplanted with the Sarcoma 180 tumor, treated with the dose of 50mg/Kg/10 days, i.p. It was observed inhibition of the tumor growth in the thalidomide treatment (56,6%) and for analogues SC-10 and SC-11 (48.2% and 41.3%, respectively), p< 0,05. The immunostaining of intratumor endothelial cells with CD-31, showed, in the form of microvascular density, reduction in the groups treated with analogues SC-10 and SC-11 (64.59% and 46.51%), but not in the groups treated with thalidomide. These results, along with previous studies of immunemodulation suggest antitumor and antiangiogenic immunity, T cells dependent, for the phthalimides analogues.

Philosophiae Doctor - PhD / The prevalence of obesity amongst South Africans is alarming, with more than 29% of men and 56% of women considered to be obese. Angiogenesis, a process for development of new blood vessels play a major role in growth and survival of the adipose tissues. Pharmacological inhibitors of angiogenesis are therefore a sensible strategy to reduce excess body weight. Current anti-obesity drugs have limitations because of their lack of selectivity and specificity, which lead to undesirable side effects and reduced drug efficacy. Future anti-obesity therapeutic strategies should be target-specific, with minimal toxicity towards healthy tissues will be more appropriate for obesity treatment. Targeted nano-therapeutic agents are currently being developed to overcome the drawbacks associated with conventional drug therapies. The nano-based delivery vehicles that specifically target diseased cells are appealing as they could reduce drug toxicity towards healthy tissues and be more effective at lower dosages. The main aim of this study was to develop a receptor-mediated nanotherapy that specifically targets the white adipose tissue vasculature and trigger the death of these cells through apoptosis. The 14 nm gold nanoparticles (AuNPs) were synthesized using theTurkevich method following reduction of gold aurate by sodium citrate salt. Different chemistries were used to functionalise the AuNPs for biological application by conjugating with either vascular targeting peptide or pro-apoptotic peptide on their surface or both. The nanomaterials were characterised by UV-Vis, Zeta potential and transmission electron microscopy (TEM). The sensitivity and specificity of various AuNP conjugates were tested in vitro on colon and breast cancer cell lines. A human (Caco-2) cell line that expresses the receptor for the adipose homing peptide was chosen as an in vitro model system. Cellular toxicity and uptake of the nanoparticles was evaluated using the WST-1 assay, Inductively Coupled Plasma-Optical Emission Spectra (ICP-OES) and TEM. The induction of apoptosis following exposure to the nanoparticles was examined by Western blot and flow cytometric analysis. The anti-proliferative activity of the targeted therapeutic nanoparticles on the cells was more pronounced on the cells expressing the receptor for the adipose homing peptide. The uptake of unfunctionalised AuNPs was higher compared to functionalised nanoparticles, but this did not impair cell viability. The activity of the therapeutic peptide was retained and enhanced following conjugation to AuNPs as shown by Western blot and flow cytometric analysis. The nanotherapy under study demonstrated receptor mediated targeting, and enhanced activity on the cells expressing the receptor. However, the therapeutic and efficacy of the targeted nanotherapy still need to be tested in animal models of obesity to confirm the treatment specificity.

The tumor-selective viral replication capacity and pro-apoptotic effects of oncolytic reovirus have been reported to be dependent on the presence of an activated RAS pathway in several solid tumor types. However, the mechanisms of selective anticancer efficacy of the reovirus-based formulation for cancer therapy (Reolysin, pelareorep) have not been rigorously studied in soft tissue sarcomas (STS). Here we report that Reolysin triggered a striking induction of the anti-angiogenic chemokine interferon-gamma-inducible protein 10 (IP-10)/CXCL10 (CXC chemokine ligand 10) in both wild type and RAS mutant STS cells. Further analysis determined that Reolysin treatment possessed significant anti-angiogenic activity irrespective of RAS status. In addition to CXCL10 induction, Reolysin dramatically downregulated the expression of hypoxia inducible factor (HIF)-1 alpha, HIF-2 alpha and inhibited vascular endothelial growth factor (VEGF) secretion. CXCL10 antagonism significantly diminished the anti-angiogenic effects of Reolysin indicating that it is a key driver of this phenomenon. Xenograft studies demonstrated that Reolysin significantly improved the anticancer activity of the anti-angiogenic agents sunitinib, temsirolimus, and bevacizumab in a manner that was associated with increased CXCL10 levels. This effect was most pronounced following treatment with Reolysin in combination with temsirolimus. Further analysis in additional sarcoma xenograft models confirmed the significant increase in CXCL10 and increased anticancer activity of this combination. Our collective results demonstrate that Reolysin possesses CXCL10-driven anti-angiogenic activity in sarcoma models, which can be harnessed to enhance the anticancer activity of temsirolimus and other agents that target the tumor vasculature.

Abstract Idiopathic usual interstitial pneumonia (UIP) and bronchiolitis obliterans organizing pneumonia (BOOP) are fibrous pulmonary disorders in both of which there is newly formed connective tissue in distal air spaces. UIP is a progressive and usually fatal lung disease without any efficient treatment, while the prognosis of BOOP is good. In both diseases, an injury of the alveolar epithelium and its basement membrane (BM) leads to migration of fibroblasts and myofibroblasts into air spaces and production of extracellular matrix by these cells. In UIP, the newly formed intraluminal connective tissue lesions cause fusion of alveolar structures and interstitial remodeling, while in BOOP the newly formed connective tissue may resolve completely. One of the major aims of the research on pulmonary fibrosis is to define the mechanisms that lead to persistence of the newly formed connective tissue and thus to irreversible fibrosis in UIP. The aim of the present study was to compare the extent of capillarization, apoptotic activity and re-epithelialization of the newly formed connective tissue in BOOP and UIP. The number of capillaries per tissue surface area was measured. Furthermore, the expression of angiogenic growth factors vascular endothelial growth factor-A (VEGF-A) and basic fibroblast growth factor (bFGF) was evaluated in the same areas, in addition to the expression of Flt-1 and Flk-1, which serve as receptors for VEGF. Apoptotic activity was analyzed using TUNEL-method, and the immunohistochemical expression of apoptosis regulating proteins bcl-2, mcl-1, and bax was studied. Finally, the extent of re-epithelialization was studied with the immunohistochemical and ultrastructural localization of laminin-5 γ2 chain, and the sites of synthesis of laminin-5 γ2 chain mRNA. In BOOP, an efficient repair process with good capillarization along with high expression of VEGF and bFGF, and orderly re-epithelialization of the newly formed connective tissue takes place after lung injury. The apoptotic activity of the newly formed connective tissue is also high, presumably leading to resolution of the intraluminal connective tissue in BOOP. In UIP, the newly formed connective tissue showed poor capillarization, inadequate re-epithelialization and low apoptotic activity. The results suggest disturbed or delayed repair process in UIP, contributing to irreversible interstitial fibrosis and remodeling.

Cultures of peripheral blood mononuclear cells (MNCs) give rise to at least two different variants of endothelial progenitor cells (EPCs), early and late outgrowth EPCs. We investigated whether microRNAs in early and late EPCs could serve as markers of internal processes that can be exploited to distinguish cell identity and functional capacity. We hypothesized that as MNCs give rise to early and late EPCs, there is a gradual change in total microRNA profile, reflecting a total change in processes within the predominant cell population. Using a candidate microRNA array, early and late EPCs showed vastly different microRNA expression profiles. MiR-146a expression increased progressively as early EPCs emerged around 5-7 days (p<0.05). Through targeting TRAF6 and IRAK1, miR-146a conferred inflammatory tolerance in early EPCs, likely contributing to their purported ability to suppress inflammation. MiR-146a knock down (KD) in endotoxin-stimulated early EPCs reduced anti-inflammatory cytokine IL-1RA (p<0.001), and increased expression of pro-inflammatory cytokines IL-1 (p<0.001) and IL-8 (p<0.01). Interestingly, the microRNA expression profile of late EPCs was highly congruent to mature endothelial cells, with 100-fold greater miR-126 expression than monocytes and early EPCs (p<0.01). MiR-126KD in late EPCs abolished matrigel-network formation (p<0.05); while overexpression (OE) in early EPC augmented network formation (p<0.05) and chemotactic migration (p<0.001). We also found that the melanoma cell adhesion molecule or MCAM (CD146) identified late EPC precursors. Only MCAM+MNCs from adult blood (<5% of total MNCs) yielded late EPC-like colonies. Robust miR-126 expression in these cells predicted the generation of late EPCs. Overall, our results suggest that miR-146a in early EPCs likely contributes to repair by suppressing inflammation during cardiovascular injury; while in late EPCs, miR-126 directly promotes angiogenesis and vascular repair. Finally, we highlight a unique method for the efficient generation of late EPCs by using MCAM selection and screening for miR-126.

Le cancer est l’une des principales causes de mortalité en France, après les maladies cardiovasculaires. Il est responsable de plus de 11 millions de décès dans le monde chaque année. Le cancer résulte d’une prolifération anarchique de cellules qui mène à la formation d’une tumeur. Les cellules tumorales peuvent ensuite migrer vers d’autres tissus pour former des métastases. La chimiothérapie est l’un des traitements les plus utilisés pour traiter le cancer. Elle consiste en l’utilisation d’agents antitumoraux qui provoquent la mort cellulaire en bloquant la mitose. Dans le but d’induire cette apoptose, nous nous sommes intéressés aux poisons du fuseau mitotique, agents cytotoxiques qui ont pour cible les microtubules et qui ont la particularité de se fixer sur leur constituant majeur, la tubuline. La dynamique des microtubules joue un rôle crucial dans la multiplication cellulaire. Bloquer cette dynamique est suffisant pour bloquer la mitose. Par ailleurs, suite à cet arrêt de la polymérisation, un second mécanisme se mettrait en place, notamment au niveau des cellules endothéliales, pour empêcher la néovascularisation, ce qui inhiberait ainsi l’angiogénèse. Notre travail consiste en la conception et la synthèse de nouveaux inhibiteurs de la polymérisation de la tubuline, potentiellement anti-angiogéniques et anti-vasculaires. Il s’agit de tricycles, qui ont la particularité d’interagir spécifiquement avec le site de fixation de la colchicine, au niveau de la tubuline, ce qui inhibe la polymérisation des microtubules et par conséquent la division cellulaire. Des tests d’inhibition enzymatique et de cytotoxicité sur plusieurs lignées cellulaires cancéreuses ont été réalisés et les résultats sont présentés dans ce rapport. / Cancer is one of the leading cause of death in France after cardiovascular diseases. Cancer results from an abnormally excessive cell proliferation which leads to the formation of a tumor. The following processes in invasion of tumoral cells and metastasis in the other tissues. Stopping mitosis by chemotherapy can cause death of cancer cells. In order to induce this apoptosis, we are interested by a class of antitumoral drugs which disrupt mitotic spindle function by focusing on its major component: the microtubules. These agents set exactly on their main structural element: the tubulin. The microtubule was recognised as a subcellular target of major strategic importance with regard to anticancer therapeutics. Our work consisted of the design and the synthesis of new antitumor drugs which influence microtubules dynamics. Theses molecules should inhibit tubulin polymerization by binding to the colchicine site. Moreover, we expect theses compounds selectively target tumor vasculature and thus can also be considered vascular disrupting agents. Enzymatic inhibition and cytotoxic assays were performed on different cell lines and are presented in this report.

Over the past few decades, inorganic nanoparticles, which exhibit significantly distinct physical, chemical and biological properties from their bulk counterpart's, have elicited much interest. Discoveries in the past decade have demonstrated that the electromagnetic, optical and catalytic properties of noble-metal nanoparticles such as gold, silver and platinum, are strongly influenced by shape and size. This has motivated an upsurge in research on the synthesis routes that allow better control of shape and size for various nano-biotechnological applications. Biomedical applications of metal nanoparticles have been dominated by the use of nanobioconjugates that started in 1971 after the discovery of immunogold labeling by Faulk and Taylor. Currently metal-based nanoconjugates are used in various biomedical applications such as probes for electron microscopy to visualize cellular components, drug delivery (vehicle for delivering drugs, proteins, peptides, plasmids, DNAs, etc), detection, diagnosis and therapy (targeted and non-targeted). However biological properties of bare-metal (naked) nanoparticles have remained largely unexplored. Therefore, in this review we discuss the novel biological properties and applications of three most widely used metal nanoparticles, namely, the nanoparticles of gold, silver and platinum. We describe the novel properties and use of these nanoparticles in angiogenesis and cancer related disorders.

Objective: Osteopontin (OPN), increased in the heart following myocardial infarction (MI), plays an important role in post-MI remodeling. Angiogenesis, an important feature of tissue repair, begins in the infarcted myocardium within 3 days post-MI. Here, the authors studied the role of OPN in myocardial angiogenesis using wild-type (WT) and OPN knockout (KO) mice. Results: Measurement of angiogenic response using Griffonia simplicifolia lectin-1 (GSL-1) staining indicated reduced capillary density in the infarcted region of the OPN KO hearts as compared to WT hearts 7 and 14 days post-MI. Arteriolar density was lower in OPN KO hearts 14 days post-MI. The number of CD31 positive cells was also lower in the infarcted region of the OPN KO hearts as compared to WT hearts 14 days post-MI. In contrast, capillary and arteriolar densities in the noninfarcted regions of OPN KO and WT hearts were not significantly different. In vivo myocardial angiogenesis measured using Matrigel implantation in the left ventricular myocardium indicated significant decrease in the percentage of vessel-like areas in the OPN KO vs. WT hearts. Furthermore, in vitro Matrigel tube formation assay demonstrated a significant decrease in total tube length in cardiac microvascular endothelial cells (CMECs) isolated from OPN KO hearts as compared to CMECs from WT hearts. Treatment of OPN KO CMECs with purified OPN protein significantly increased total tube length, while bovine serum albumin had no effect. Conclusion: Lack of OPN impairs myocardial angiogenic response, leading to adverse remodeling post-MI.

ALK1 (Actlivin receptor-Like Kinase 1) est un récepteur exprimé spécifiquement sur les cellules endothéliales. ALK1 possède deux ligands de haute affinité BMP9 (Bone Morphogenic Protein) et BMP10. Cette voie de signalisation joue des rôles cruciaux dans l'angiogenèse et la lymphangiogenèse qui sont des processus critiques dans le développement mais aussi le cancer. Ainsi, l'objectif de cette thèse était de caractériser les fonctions de BMP9 et BMP10 dans le développement vasculaire physiologique et tumoral à l'aide de souris invalidées pour ces deux facteurs.Nous avons montré que BMP9 et BMP10 sont essentiels à la fermeture du canal artériel. Ce vaisseau permet de dévier le sang hors des poumons foetaux non fonctionnels et sa fermeture au moment de la naissance est nécessaire à la survie postnatale. L'absence de BMP9 et BMP10 mène à une réouverture du canal artériel chez le souriceau du fait de problèmes de remodelage. Chez l'Homme, une région critique contenant Bmp10 peut être corrélée à des problèmes de fermeture du canal artériel.Des essais cliniques ciblant ALK1 dans le traitement du cancer sont en cours du fait de son implication dans l'angiogenèse. Néanmoins, les rôles spécifiques de BMP9, BMP10 et ALK1 dans le cancer sont encore mal connus. Nous avons montré que BMP10 n'est pas impliqué dans la tumorigenèse mammaire au contraire de BMP9 qui agit comme un facteur de quiescence et de maturation dans l'angiogenèse tumorale. Ainsi, il serait plus intéressant de cibler spécifiquement BMP9 plutôt qu'ALK1 afin d'éviter d'altérer les fonctions physiologiques de BMP10. / ALK1 (Actlivin receptor-Like Kinase 1) is a receptor specifically expressed at the surface of endothelial cells. BMP9 (Bone Morphogenic Protein) and BMP10 are the high affinity ligands of ALK1. This pathway has been proved to play important roles in angiogenesis and lymphangiogenesis which are critical processes in development as well as in cancer. Thus, the purpose of my PhD was to characterize BMP9 and BMP10 functions in physiological and tumoral vascular development using mice invalidated for those proteins.We show that BMP9 and BMP10 are essentials to ductus arteriosus closure, a shunt allowing blood to avoid inoperative foetal lungs. Its closure is mandatory to survival after birth. Loss of BMP9 and BMP10 leads to ductus arteriosus reopening in mice pups due to remodeling issues. In human, a critical region including Bmp10 was correlated to patent ductus arteriosus.Clinical trials targeting ALK1 in cancer treatment are in progress due to its involvment in angiogenesis. However, little is known about the specific roles of BMP9, BMP10 and ALK1 in carcinogenesis. We show that BMP10 is not involved in mammary cancer development while BMP9 acts as a quiescent and maturation factor in tumoral angiogenesis. Thus, it may be more interesting to target only BMP9 instead of ALK1 to avoid interferences with BMP10 physiological functions.