Tumours are not autonomous transformed cell populations, but rather a society composed of both malignant and normal, including immune, cells that together foster tumour growth and development. Tumour-associated macrophages have been reported to enhance tumour growth, progression and metastasis. In high-grade non-Hodgkin’s lymphomas, prototypically the B-cell neoplasm, Burkitt’s lymphoma (BL), infiltrating macrophages engulf large numbers of apoptotic tumour cells. Evidence suggests that apoptotic BL cells can condition the tumour microenvironment to promote lymphoma development by selectively attracting macrophages while inhibiting neutrophil infiltration and by stimulating macrophages to produce the B-cell growth and survival factor. Tumour cells grow in a hypoxic and nutrient-deficient environment and the resultant cellular stress can induce apoptosis. It is therefore possible that hostile environmental conditions in the tumour also contribute to the generation of a pro-tumour microenvironment. This thesis describes investigations which examined this hypothesis. BL cells were cultured at high density to mimic conditions of metabolic stress existing in the tumour environment. Cell-free supernatants from such stressed BL cells demonstrated potent chemoattractive activity for mononuclear phagocytes. Supernatants from BL cells that were protected from apoptosis by over-expression of bcl-2 had similar ability, confirming that chemoattractant release was apoptosis-independent. The observation that apyrase and suramin could inhibit the chemotactic activity of these supernatants suggested that nucleotides might be the apoptosis-independent chemoattractant. Detection of ATP in stress supernatants by bioluminescence assay was consistent with this proposal. Significantly, supernatants from BL cells and those transfected with bcl-2 were both found to inhibit neutrophil migration, suggesting the occurrence of a neutrophil migration inhibitory factor whose release was apoptosis-independent. Furthermore, stress supernatants could promote BL cell proliferation in vitro, which was apoptosis and cell line-independent. In order to study the role of TAM in the tumour microenvironment, a novel macrophage model was devised using mouse embryonic stem cells (ES cells). Cells derived from ES cells generated in vitro expressed macrophage-specific markers and were free of dendritic cells and undifferentiated ES cells. ES cell-derived macrophages (ESDM) could migrate towards apoptotic BL cells and engulf them. However, ESDM migrated to stress supernatants with decreasing efficiency as they matured. Preliminary data indicated that the phagocytic ability of ESDM to engulf apoptotic cells increased as they matured, consistent with distinct roles for circulating monocytes and tissue macrophages with regard to this function. Considering the high yields and purities of ESDM described here, together with their non-malignant nature and genetic versatility these cells should provide a superior source of undifferentiated mononuclear phagocytes with which to elucidate the molecular mechanisms underlying tumour infiltration and microenvironmental conditioning by TAM. In conclusion, this work suggests that under conditions of pre-apoptotic stress, BL cells have the capacity to regulate their micro-environment upstream of their apoptosis programme to promote net tumour growth through paracrine signals that attract supportive macrophages and inhibit destructive neutrophils and through release of autocrine/juxtacrine tumour growth factors.

Acrocomia é do gênero pertencente à família Arecacea, nativa de florestas tropicais. A polpa do fruto macaúba tem usos alimentícios, como sucos, geleias, sorvetes que possuem substâncias bioativas, “ditas funcionais”, como antioxidantes, fibras e minerais imunomodularodes como o Zinco. Sabe-se que fibras e compostos antioxidantes têm ação estimulante para o tratamento de inflamações. O presente trabalho teve como objetivo investigar a atividade antibacteriana e anti-inflamatória dos extratos e das frações do óleo do mesocarpo da Acrocomia aculeataobtidas por extração a frio e as frações por cromatografia de coluna. Ascepas bacterianas foram tratadas com os extratos à uma concentração de 5mg/ml para a avaliação da atividade bacteriana e para controle positivo foi utilizado o antimicrobiano convencional Imipenen. Na avaliação da atividade antibacteriana foi observado que nenhum dos extratos testados mostraram atividade frente às bactérias Grampositivas e Gram-negativas. Quanto a avaliação da atividade de mediadores da inflamação, as células foram tratadas com os bioativos oleoso do mesocarpo da macaúba e estimuladas com LPS. Após 24 horas o sobrenadante celular foi coletado para avaliação da produção de óxido nítrico (NO•) pela reação de Griess. Analisandoos efeitos sobre a produção de mediadores inflamatórios, foi observado no primeiro ensaio que as frações hexânica (FHex) e metanólica (FMeOH)na concentração de 25 e 50 μg/ml inibiram a produção de NO•, em células macrófagos murino J774 estimulados por LPS. Em ensaios posteriores nas mesmas condições não demonstrou nenhum tipo de atividade, sugerindo a realização de estudos futuros na obtenção do extrato, ou no fracionamento em cromatografia de coluna e até mesmo adaptações nos métodos usados neste trabalho. Este estudo pode fornecer uma base para investigações futuras sobre o papel terapêutico do óleo do mesocarpo no tratamento da inflamação. / Acromonia is a gender belonging to the Arecaceae family and native from the tropical forests. Food is one of the many subjects related to the fruit pulp from macauba, for example: juices, jellies, ice-creams which possess bio actives substances, called as antioxidant, fibers and immune modulators minerals like the Zinc; it is known that fibers and antioxidant compounds have stimulating action to inflammations treatments. This study had the purpose to investigate the antibacterial activity and anti-inflammatory from the extracts and fractions of the Acrocomia aculeata mesocarp oil achieved by extraction of fractions from the spine chromatography. The bacterial vines were treated with the extracts concentration of 5mg/ml to evaluate the bacterial activity e to the positive control was used the conventional antimicrobial Imipenen. In the evaluation of the antibacterial activity was observed that none of the tested extractions showed activity upon the Gram-positives and Gram-negatives bacteria’s. As for the activity evaluation of inflammation mediators, the cells were treated with oil bio actives from macauba’s mesocarp and stimulated with LPS. After 24 hours the cellular supernatant was collected to evaluation of nitric oxide production (NO°) for reaction of Griess. Analyzing the effects under the production of inflammatory mediators, was observed that in the first test that the hexanica fractions (FHex) and metalonica (FmeOH) in concertation of 25 and 50 mg/ml inhibited the NO° production, on macrophages murine J774 cells stimulated by LPS. On further tests in the same conditions doesn’t showed any kind of activity, suggesting for future studies futures observations on obtain the extract or on fractioning on spine chromatography or even for the same adaptations on methods used in this study. This work can provide a base to future investigation about the therapeutic paper of mesocarp oil on inflammation treatment.