Componentes da resposta inflamatória aguda que favorecem a progressão do melanoma e, modelo murino. / Components of the acute inflammatory response that promote the progression of melanoma in a murine model

AUTOR(ES)

Andre Luis Lacerda Bachi

DATA DE PUBLICAÇÃO

2009

RESUMO

Chronic inflammation is one of the main factors that predispose to cancer development and contribute to tumor progression. However, some studies show that acute inflammation is also able to generate a microenvironment favorable to the growth of certain tumors. In our laboratory, Correa et al. showed that injection of a large amount of apoptotic cells creates favorable conditions for the growth of a subtumorigenic dose of viable Tm1 melanoma cells [2]. Thus, we evaluated whether other inflammatory stimuli have the same potential to create favorable conditions for the melanoma growth, as well as the role of inflammatory pathways (cyclooxygenase and lipoxygenase) and their products in this model. We also studied the participation of platelet-activating factor and its receptor, which are the cells recruited to the microenvironment and which is the effect of polyunsaturated fatty acid omega-3 in this inflammatory response. The results showed that, similarly to injection of a large number of apoptotic cells, LPS and carrageenan, have the same ability to enhance growth of subtumorigenic dose of melanoma cells. Moreover, while the cyclooxygenase pathway and platelet-activating factor did not show any action, PAF receptor, the 5-lipoxygenase inflammatory pathway, and particularly its product, leukotriene B4, participate in this process. Regarding omega-3, we observed that products of its metabolism, such as eicosapentaenoic acid and leukotriene B5, were able to inhibit tumor growth associated with the inflammatory stimulus. These results suggest that the presence of massive apoptosis or potent inflammatory stimuli in a tissue favors the growth of a subtumorigenic dose of melanoma cells. This phenomenon may be related to the occurrence of relapses in patients with cancer after treatment with radiation and chemotherapy.

ASSUNTO(S)

imunologia 1. microambiente tumoral. 2. inflamação aguda. 3. vias inflamatórias 4. leucotrienos. 5. Ômega 6 e 3. 6. melanoma

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