Abstract
Studies have shown that Crotoxin (CTX), majority toxin from Crotalus durissus terrificus snake venom presents suppressive action on the immune response and on tumor growth, besides causing inhibition of the events of the inflammatory response by modulating, in particular macrophages functions, cells critical to the mechanisms of innate defense. Studies by our group have shown that CTX stimulates the secretory capacity of rat peritoneal macrophages obtained from animals with Walker 256. This increase is accompanied by a significant decrease in tumor mass. In addition, in vitro assays demonstrated that macrophages pretreated with CTX inhibit the proliferation of tumor cells in co-culture model, which is mediated, in part, by increased production of oxygen and nitrogen reactive, IL-1² and the generation of LXA4 and 15-epi-LXA4. In fact, the literature has shown the importance of macrophages in both tumorigenesis as in its development, featuring dual action, since they play activities that can prevent or promote tumor progression. Besides the action on the proliferation of tumor cells, macrophages also influence the process other events in tumor such as neovascularization. Since it was shown that CTX modulates the macrophages functions, the aim of this study is to investigate whether the secretory activity of macrophages treated with CTX interferes with key events of neovascularization, such as adhesion, migration and proliferation of endothelial cells. To do so, using in vitro model of angiogenesis, supernatants from macrophages or CTX-treated co-culture supernatants from macrophages pretreated with toxin and LLC tumor cells of the line 256 WRC be added to the culture of thymic endothelial cells (t.End.1) and evaluated the following parameters: 1) the behavior of the adhesion to its natural ligands, such as collagen I and fibronectin, using competition assay, 2) the proliferative capacity, 3) the migration of on extracellular matrix using the Wound healing and transwell methods and 4) capillary morphogenesis assay in Matrigel, in the 3D model; 5) release of VEGF and MMP-2 and MMP-9, through immunoassay test (EIA).
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