EFFECTS OF DIETARY COMPOUNDS ON THE INTERCELLULAR COMMUNICATION MEDIATED BY EXTRACELLULAR VESICLES IN MAMMARY TUMORS

ÉRICA DANIELA SOLLA; FRANCO FABIÁN ROLDÁN GALLARDO; TAMARA MAGALÍ MAZO; VICTORIA FERRERO; MARÍA EUGENIA PASQUALINI; CRISTINA ALICIA MALDONADO; AMADO ALFREDO QUINTAR

Mar de Plata

Congreso; ANNUAL MEETING OF BIOSCIENCE SOCIETIES 2022; 2022

Sociedad argentina de investigación clinica

Carbohydrate- and fatty acid-rich dietary patterns (CAP and FAP),represented mainly by fructose (F) and palmitic acid (PA) respectively,are strongly associated with breast cancer, with the cellularmechanisms being far to be fully elucidated. We aimed to evaluatethe dietary effects on the microenvironment interactions between cancer-associated fibroblasts (CAFs) and tumoral cells mediated byextracellular vesicles (EVs). Balb/c mice fed on CAP, FAP or CAP+-FAP mixture for 2 months were s.c. implanted with LM3 mammarytumor cells for 20 days. When compared with chow diet, CAP+-FAP tumors grew faster and developed a larger volume (p<0.05);by electron microscopy, a higher frequency of CAFs, collagen andultrastructural signs of increased secretion of EVs were seen. Forin vitro studies, the mammary CAFs cell line F88 was cultured andstimulated with F40mM, AP250uM, F+PA combinations or theirvehicles for 24h. Supernatants were collected and EVs isolated bysequential ultracentrifugation (2k, 10k, 100k), characterized by electronmicroscopy, and labeled with CD63 using immunogold technique.F+PA induced an increase in the frequency of 20-30 nm-sizedEVs with respect to controls or F and PA alone (p<0.05). To evaluatethe effect of EVs from CAFs on tumor cell proliferation, MCF-7 mammarytumor cells were stimulated for 24h with conditioned media orwith EVs derived from F-, AP-, and F+PA-treated F88 cells. Conditionedmedia from F88 treated with F+PA increased cell proliferationof MCF7 cells, determined by incorporation of bromodeoxyuridineand cell count (p<0.05), with this effect being reproduced with EVsfrom F+PA-treated F88. This pro-tumoral action of EVs was inhibitedby pre-incubating MCF7 with genistein, suggesting EVs uptake in aclathrin-independent manner. These results indicate a pathogeniceffect of dietary patterns rich in F and PA on mammary tumor microenvironment,through the release of pro-proliferative EVs by CAFs.