Atheromas contain hypoxic areas which upregulate HIF1α expression, promoting angiogenesis and unstable lesion formation. Simvastatin stabilises atheromas through preventing rupture and neovascularisation. Atheromas express matrix metalloproteinase 14 (MMP14) which degrades matrix proteins and promotes neovascularisation. MMP14 is upregulated by hypoxia and contains Hypoxic-Inducible Factor (HIF) recognition sequences (5’-RCGTG-3’). My project sought to investigate if HIF1α interacts with the MMP14 promoter to enhance MMP14 expression, and whether simvastatin attenuates this effect, inhibiting angiogenesis. Immunostaining of atheromas identified MMP14 and HIF1α localisation. Protein-DNA binding assays were performed on human umbilical vein endothelial cells (HUVECs) and showed HIF1α bound to the MMP14 promoter in hypoxia, which was significantly decreased by simvastatin. To assess gene regulation, a human MMP14 promoter-firefly luciferase reporter construct was transfected into C166 endothelial cells alongside HIF-overexpression plasmids and mutations of the MMP14 promoter region at HIF recognition sequences. Overexpression of HIF1α and HIF1β increased MMP14 activity which was abolished by introducing the mutations and diminished by simvastatin in a HIF-dependent manner. Immunoblots, flow cytometry, scratch assays and bromodeoxyuridine incorporation showed HIF1α knockdown and simvastatin significantly attenuated hypoxia upregulated MMP14 expression, migration and proliferation in a HIF1α-dependent manner. Angiogenesis was assessed using in vivo sponge angiogenesis assays and ex vivo aortic ring assays cultured in hypoxia or normoxia, with or without 0.1μM simvastatin, and MMP14 inhibitor, utilising HIF1αfl/flTie1Cre+ and wildtype littermates. Simvastatin perturbed angiogenesis through decreasing MMP14 expression in a HIF1α-dependent manner. The results show hypoxia upregulates MMP14 through HIF1α interaction with the MMP14 promoter. Simvastatin attenuates MMP14 upregulation which reduces HIF1α:MMP14 promoter interaction. HIF1α knockdown and simvastatin treated HUVECs show less migration and proliferation, equivalent to that of MMP14 inhibition. Simvastatin inhibits neovascularisation in a HIF1α-dependent manner. These results suggest simvastatin may stabilise atheromas through inhibiting MMP14 driven angiogenesis which may have further implications in the treatment of atherosclerosis.

Reproduction de : Thèse doctorat : Pharmacie.Biochimie-Biologie moléculaire : Reims : 2007. / Titre provenant de l'écran-titre. Bibliogr. p.186-218.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O cÃncer colorretal(CCR) à altamente prevalente nos paÃses mais ricos e industrializados. As metaloproteinases de matriz (MMPs) sÃo importantes enzimas que facilitam a invasÃo e disseminaÃÃo do tumor em vÃrios tipos de cÃncer, inclusive o colorretal. Os inibidores teciduais de metaloproteinases (TIMPs) sÃo os principais inativadores fisiolÃgicos destas enzimas. Este estudo avaliou a expressÃo de metaloproteinase-2 (MMP-2), metaloproteinase-14 (MMP-14) e inibidor tecidual de metaloproteinases-2 (TIMP-2) no cÃncer colorretal. O imunomarcador CD68 foi utilizado para caracterizar a natureza das cÃlulas mononucleadas do estroma. Amostras teciduais de 50 casos de colectomias, devido ao cÃncer colorretal no perÃodo de 2004 a 2010, obtidas dos arquivos do Departamento de Patologia e Medicina Legal (DPML), Faculdade de Medicina da Universidade Federal do Cearà (UFC), foram analisadas. Realizou-se tissue microarrays e a seguir imuno-histoquÃmica para avaliar a expressÃo de MMP-2, MMP-14 e TIMP-2 de acordo com os seguintes escores baseados em outros relatos: 0= sem imunomarcaÃÃo ou raras cÃlulas marcadas (<5%); 1 = discreta marcaÃÃo na maioria (> 50%) das cÃlulas tumorais ou cÃlulas mononucleares do estroma, ou moderada marcaÃÃo em uma minoria de cÃlulas (<50 %); 2 =marcaÃÃo moderada na maioria (> 50%) de cÃlulas tumorais ou cÃlulas mononucleares ou intensa marcaÃÃo em minoria de cÃlulas (<50%); 3 = marcaÃÃo intensa na maioria (> 50%) de cÃlulas tumorais ou cÃlulas mononucleares. Observou-se relaÃÃo entre a expressÃo aumentada de MMP-14 em mononucleares de tumor primÃrio e casos sem metÃstases linfonodais (MMP-14, escores 2 e 3/N0 : 23/24 = 95%; N1-N3: 14/20 = 70%, p = 0,0353). No entanto, nenhuma relaÃÃo significativa foi encontrada entre a expressÃo de MMP-14, MMP-2 e TIMP-2 nos tumores primÃrios em cÃlulas cancerosas ou mononucleares e outros parÃmetros clÃnico-patolÃgicos. A imunoexpressÃo de MMP-2 foi negativa nas cÃlulas neoplÃsicas, em tumores primÃrios (47/47=100%) e metastÃticos (12/12 = 100%). A imunorreatividade de MMP-14 em cÃlulas neoplÃsicas foi frequentemente positiva em tumores primÃrios (50/50 = 100%) e metastÃticos (7/8= 88%). Em mononucleares, a maioria dos quais macrÃfagos (corados pelo CD68), a expressÃo positiva de MMP-14 tambÃm predominou marcadamente, tanto em tumores primÃrios (46/47 = 98%) como em carcinomas metastÃticos (9/10 = 90%). A expressÃo de TIMP-2 em cÃlulas neoplÃsicas, discreta, ocorreu em 70% de tumores primÃrios (35/50 casos) e 100% dos metastÃticos (8/8). A imunocoloraÃÃo para TIMP-2 em macrÃfagos associados ao tumor (TAMs) foi ainda mais elevada do que nas cÃlulas neoplÃsicas. Em conclusÃo, a MMP-14 e TIMP-2 sÃo frequentemente expressas em carcinomas colo-retais em ambas localizaÃÃes anatÃmicas, principalmente nas metÃstases para linfonodos , sugerindo que estas proteases desempenham papel importante na invasÃo local e na progressÃo tumoral neste tipo de cÃncer. A predominÃncia destes marcadores nas cÃlulas mononucleares (sobretudo macrÃfagos) , claramente evidentes na positividade para a MMP-2, enfatiza a importÃncia do microambiente tumoral no desenvolvimento de neoplasias. / The colorectal cancer (RCC) is highly prevalent in richer and industrialized countries. The matrix metalloproteinases (MMPs) are regarded as important for facilitating tumor invasion and spread in various cancers, including colorectal. Tissue inhibitors of metalloproteinases (TIMPs) are the major physiological inhibitors of MMPs. The expression of metalloproteinase-2 (MMP-2), metalloproteinase 14 (MMP-14) and tissue inhibitor of metalloproteinases-2 ( TIMP-2) in colorectal cancer was assessed. CD68 immunostaininig was utilized to the characterization of mononuclear cells nature. Paraffin-embedded tissues from patients undergoing colectomy for colorectal cancer in the period 2004 to 2010, were selected from the files of the Department of Pathology and Forensic Medicine (DPML), Medical School , Federal University of Cearà (UFC). Tissue microarrays were performed and slides were obtained for immunohistochemical detection of the expression of MMP-2, MMP-14 and TIMP-2 and the tissue samples analyzed. The following scores were applied: 0 = no immunostaining or rare labeled cells (<5%), 1 = slight marking the majority (> 50%) of tumor cells or stromal mononuclear cells, or moderate marking in a minority of cells (<50%) 2 = moderate labeling in the majority (> 50%) of tumor or mononuclear cells or intense marking in the minority of cells (<50%) and 3 = intense labeling in the majority (> 50%) of tumor cells or mononuclear cells. In this study, the relationship between increased expression of MMP-14 in mononuclear primary tumor cells and cases without lymph node metastases (MMP-14, 2 and 3/N0 scores: 23/26 = 88%; N1-N3: 14/21 = 67%, p = 0.0353) was stablished . However, no significant relationship was found between the immunohistochemical expression of MMP-14, MMP-2 and TIMP-2 in primary tumors in cancer cells and mononuclear cells and other clinico-pathological parameters. The expression of MMP-2 were negative in the neoplastic cells both in primary tumors (47/47 = 100%) and in metastatic ones (12/12 = 100%). The immunoreactivity of MMP-14 in neoplastic cells in primary tumors was positive (50/50 = 100%) and in all cases except one of metastatic carcinoma (7/8 = 88%). In mononuclear cells, most of them characterized as macrophages (CD68 stained), MMP-14 positive expression also predominated markedly, both in primary tumors (46/47 = 98%) and in metastatic carcinomas (9/10 = 90%). TIMP-2 expression in neoplastic cells of primary tumors occurred in 35/50 cases (70%) and lymph nodes showed positive immunostaining in all cases (8/8 = 100%). In both sites there were no cases with high expression. The TIMP-2 immunoreactivity in tumour associated macrophages (TAMs) was even higher than in the neoplastic cells. In conclusion, MMP-14 and TIMP-2 are frequently expressed in colorectal carcinomas in both anatomical sites , mainly in lymph node metastasis, suggesting that these proteases play an important role in local invasion and tumor progression of these cancers. The predominance of these biomarkers in mononuclear cells, clearly evident in the positivity for MMP-2, emphasizes the importance of tumor microenvironment in the development of neoplasms.

Indiana University-Purdue University Indianapolis (IUPUI) / The negative heath consequences of smoking are widely recognized, but there are still about 20% of the people in United States using tobacco products. Cigarette smoke condensate (CSC), the particulate matter of cigarette smoke, is comprised of thousands of chemicals (e.g., nicotine). Secondary only to bacterial plaque, cigarette smoking is a major risk factor for periodontal disease. Human gingival fibroblasts (HGFs) are the main cellular component of periodontal connective tissues. During the development of periodontal disease, collagen degradation occurs. Collagen is the major extracellular matrix component of the gingiva. The major extracellular matrix degrading enzymes produced by the HGFs are the matrix metalloproteinases (MMPs). The MMPs are mainly modulated by the tissue inhibitors of metalloproteinases (TIMPs). In this dissertation, three studies aimed at understanding the effects of tobacco on human gingival fibroblasts and their mechanisms have been conducted: the effects of CSC on HGF-mediated collagen degradation; comparison of the effects of CSC on HGFs with that of nicotine; and the combined effects of CSC and bacteria on HGFs. The cell proliferation of HGFs decreased and cytotoxicity increased in HGFs treated with increasing concentrations of CSC. CSC increased the collagen degrading ability of the HGFs by altering the production and localization of MMPs and TIMPs. Nicotine is one of the major components and the most pharmacologically active agent in tobacco. The percentage of nicotine in the CSC was 2.4%. CSC (100 µg/ml) increased the collagen degrading ability of the HGFs by affecting membrane associated MMP-2, MMP-14, and TIMP-2, but the level of nicotine in the CSC may only play a limited role in this process. Porphyromonas gingivalis (P. gingivalis) is an opportunistic pathogen involved in periodontal disease. The combined effects of CSC and P. gingivalis supernatant increased HGF-mediated collagen degradation by destroying the balance between the MMPs and TIMPs at the protein and mRNA levels. This project demonstrated that tobacco (with or without P. gingivalis) increased HGF mediated collagen degradation, as seen in the periodontal disease, through altering the MMPs and TIMPs.