Breast cancer is a worrying disease due to its high mortality and morbidity rate. It is caused by different types of tumors which are treated majorly by hormonal therapy. Triple-negative breast cancer, who lacks hormone receptors to estrogen and progesterone, are unable to be treated by hormonal therapy and thus develop more aggressively. The high mortality rate from breast cancer is correlated to metastasis, a process in which tumor cells acquire an invasive, migratory phenotype and detach from the primary tumor, invading adjacent tissues and reaching distant sites. Tumor cells release extracellular vesicles (EVs), which are capable of altering the microenvironment for implantation of an invading tumor cell. EVs interact with other cells through surface integrins, heterodimeric receptors for adhesion that are fundamental for EV uptake by stromal cells. This way, through the secretion of ECM-remodeling factors, EVs induce healthy cells to aid tumor progression. In this proposal, we intent to verify the role of integrin avb3 in the transfer of EVs from triple-negative breast tumor cells (MDA-MB-231-GFP-CD63) to endothelial cells (HUVEC) and its subsequent phenotypical transformation. As a tool for blockage of integrin avb3, whose importance in EV uptake and adhesion has been previously demonstrated by our lab group, we propose the use of disintegrin DisBa-01. We shall employ a novel experimental strategy using the quasi-vivo co-culture system, which allows intercellular communication through a constant flow of culture media. For analysis of EV exchange detection, cell phenotype and protein expression, we propose methods for protein detection (Western blotting and flow cytometry) and fluorescence morphological assays.
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