Análise da formação de corpúsculos lipídicos, síntese de mediadores inflamatórios e perfil de macrófagos murinos em modelos de interação com células tumorais in vitro

Abstract

Cancer is a disease of global scope, being the second leading cause of death in the population. Lipogenesis and the presence of numerous lipid bodies (LBs) are pathological observations seen in neoplasms. LBs are organelles composed of neutral lipids and surrounded by a phospholipid monolayer, and exert functions such as production of inflammatory mediators; their increased number in tumors is associated with angiogenesis and neoplastic progression. The aim of this study was to evaluate LBs formation and synthesis of inflammatory mediators in mammary tumor cell lines and in macrophages stimulated with 4T1 and 67NR conditioned medium, and to investigate the profile of macrophages in the cancer-immune cell interaction model. Metastatic (4T1) and non-metastatic (67NR) mammary tumor cell lines were maintained in culture under standard condition and; peritoneal macrophages (Mø) were taken from C57BL/6 mice, subsequently receiving pretreatments with 1μM GW, 5μM rosiglitazone and 20nM Rapamycin. After 30 minutes the Mø were stimulated with the conditioned media of the 67NR and 4T1 mammary tumor cell lines, and incresead with the treatment with GW, rosiglitazone, rapamycin or 100nM vitamin D (VD). Data pointed out in the cytotoxicity triggered by VD in the metastatic lineage 4T1 in the analyzed times, besides its administration reducing the formation of LBs in stimulated macrophages. Regarding the use of PPARγ agonist (rosiglitazone) and antagonist (GW9662), an increase in LB formation mediated by the use of rosiglitazone was observed, while the reduction of this organelle was significantly observed in the treatment with GW9662. Preliminarily, the use of rapamycin, an mTOR inhibitor, was shown to reduce LB synthesis in mammary tumor cell lines, and the same phenomenon was noted in macrophages stimulated with the supernatant of tumor cell lines in both analyzed times. Pro- and anti- inflammatory cytokines were dosed in the supernatant of macrophages treated with rapamycin, demonstrating that the inhibition of lipid body biogenesis is independent of NF-κB activation, besides demonstrating a modulation in the response of Mø stimulated with the metastatic lineage (4T1) is timedependent, since the antitumor responsiveness occurred within 48 hours. The use of these drugs proved to be effective in modulating lipid metabolism, and corroborate new therapeutic strategies in neoplasms.