Efeito da IgA extraído do colostro sobre linhagens de células de tumor de mama

Abstract

Breast cancer is one of the most common diseases among women, but the search for more effective treatments is still a challenge. Clinical and epidemiological studies show that breastfeeding has a protective effect on the risk of breast cancer. The secretory IgA (SIgA) in human milk is important in maternal protection. Among the functions of this antibody are the neutralization of microorganisms, potentiation of phagocytosis, and interactions with cells present in the colostrum itself. However, the functions of this antibody extracted from colostrum itself on colostrum macrophages in the presence of breast tumor cells remain to be elucidated. Objective: This study aimed to evaluate the effects of IgA extracted from colostrum on the oxidative mechanisms of macrophages in coculture with breast tumor cells (MCF-7). Methodology: 20 colostrum samples were collected to obtain colostrum and cell supernatant. The supernatant was used to extract IgA using affinity chromatography. ELISA quantified the concentration of IgA. Colostrum macrophages were obtained by density gradient, and ATCC (American Type Culture Collection, USA) breast adenocarcinoma cell lines (MCF-7) were used for coculture assays. Oxidative stress was assessed in colostrum macrophage culture stimulated or not with colostrum SIgA (final concentration of 100 ng/mL), in the presence or absence of MCF-7, through the release of superoxide anion (O2 -) and activity of the enzyme superoxide dismutase (SOD). Results: The purification of IgA resulted in 3 eluates rich in SIgA, with approximately 40% of the total IgA in the fresh colostrum samples. It was observed that there was an increase in the release of O2- when compared to the spontaneous release by macrophages in the presence of SIgA. MCF-7 cells showed an increase in O2- and a reduction in SOD concentration. Macrophages treated with SIgA in coculture with MCF-7 cells showed increased O2 - . Conclusion: These results suggest the pro-oxidative effects of SIgA from colostrum on the oxidative metabolism of cells in the presence of breast tumor cells. This activation of colostrum cells via SIgA extracted from colostrum could be an alternative for future therapeutic applications.