Papel da obesidade e do desenvolvimento de tumores de mama na resposta inflamatória durante infecções por patógenos intracelulares: análise de corpúsculos lipídicos e mediadores inflamatórios em macrófagos

Abstract

Breast cancer is a malignant neoplasm that develops in the breast tissue, characterized by the uncontrolled growth of epithelial cells. It’s the most frequent cancer in women and is influenced by obesity. As obesity and cancer conditions that drive to a chronic inflammatory process, have a need to study the mediators of this reaction and possible consequences for the organism. Lipid bodies (LB) are dynamic organelles involved in lipid metabolism and intracellular signaling, which is increase in number and size in leukocytes involved in the inflammatory, neoplastic and infectious processes, including intracellular Mycobacterium bovis BCG and Trypanosoma cruzi. The lipogenesis is associated with poor prognosis in several cancers, suggesting the role of LB in cancer development. Therefore, this study presents the correlation of breast tumor and obesity in the inflammatory response during infection by M. bovis BCG and T. cruzi. For this purpose, Balb/ c female mice were treated with standard and fat diet for 16 weeks and stimulated with tumor cells 4T1 for 14 days. Macrophages were extracted from adipose tissue and peritoneum and restimulated in vitro with M. bovis BCG and T. cruzi for analysis of formation of LBs, cytokines, and eicosanoids. The results showed that macrophages obtained from obese animals stimulated with tumor cells in vivo and with BCG and T. cruzi in vitro, LBs showed a number considerably increased, showing that the presence of tumor cells and obesity are capable of stimulating inflammatory process, having for training these organelles. Moreover, macrophages from obese animals had higher production of PGE2 and expression of COX-2 than in thin animals. It has also been shown that macrophages from obese animals when restimulated with tumors exhibited a significant increased synthesis of leptin and cytokine TNF-α, TGF-β compared to macrophages from thin animals with tumors. In conclusion, our results suggest that tumor growth, together with obesity, enhances the formation of LBs and the synthesis of inflammatory mediators during infections by intracellular pathogens such as BCG and T. cruzi, suggesting the role of target LBs for future therapeutic interventions to influence the balance of the interactions between the pathogen and the host.