Effects of conditioned media from fibroblasts stimulated by dietary components on breast tumoral cells

Abstract

Published evidence suggests a strong association between nutrition and the development and maintenance of tumoral processes. In Córdoba, a greater adherence to dietary patterns (DP) provided by carbohydrates- and saturated fatty acids-rich food, represented mainly by fructose (F) and palmitic acid (PA), is positively associated with the risk of colorectal and breast cancer. However, the cellular mechanisms by which these components promote tumor aggressiveness are not fully understood. Our objective was to evaluate in vitro the role of tumor-associated fibroblasts (CAFs) as mediators of the proliferative effects of F and PA. F88 cell line, corresponding to human breast cancer CAFs, was grown in DMEM with 10% FBS and stimulated with F 40 mM, AP 250 uM, combinations of both (F+PA) or their respective vehicles, for 24 hours (characteristic concentrations of DP in Cordoba). Subsequently, supernatants were removed, total proteins were quantified and stored at -80 °C for assays. Breast epithelial tumor cells of the MCF7 line were cultured in DMEM medium with 10% FBS and then stimulated with conditioned media (from F88 cells) for 24 hours. As controls, conditioned media from vehicle-treated cells were used.

Any of the stimuli did not cause statistically significant changes in F88 cell proliferation. F + AP combination did induce a strong phenotypic change, with greater development of proteinopoietic and secretory organelles when observed by transmission electron microscopy. In addition, stimuli with PA and F + PA produced a decrease in the expression of Fibroblast Activation Protein (FAP) by western blot. On the other hand, MCF7 cells when stimulated with conditioned media from F88 treated with F + PA showed an increase in cell proliferation (ANOVA, p <0.05), determined by incorporation of bromodeoxyuridine and cell count. However, there were no significant differences between F and PA individually.

These results suggest a pathogenic effect of food rich in F and PA on tumor proliferation in breast cancer, which would be mediated by CAFs.