Role of shear stress and extracellular vesicles derived from breast tumor cells in the behavior of endothelial cells

• Grant number: 20/15696-4
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2022
• End date: September 30, 2024
• Field of knowledge: Biological Sciences - Morphology - Cytology and Cell Biology
• Principal Investigator: Vanessa Morais Freitas
• Grantee: Vanessa Morais Freitas
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: André Zelanis Palitot Pereira

Abstract

Breast cancer is the most common type of cancer in women, presenting high incidence and mortality worldwide. The most aggressive and invasive subtype of breast cancer is triple-negative (TN), showing low response to therapy and poor prognosis when metastatic. Metastasis is one of the hallmarks of cancer, consisting of a multistep phenomenon started by the shedding of cancer cells from the tumor bulk to the circulatory system followed by colonization of distal organs - the metastatic niches. However, the mechanisms that lead to the preparation of the metastatic niches are still not clear. An increasing amount of published data shows that the extracellular vesicles (EVs) may play an important role in preparing the pre-metastatic niche. EVs are lipid bilayer-delimited particles shed by cancer cells that carries a plethora of biomolecules such as proteins, lipids and also nucleic acids (DNAs, mRNAs, and microRNAs) from the cell-of-origin to the surroundings, stablishing a paracrine communication between the tumor and its local and distal microenvironment. Recent studies showed the role of EVs secreted by breast cancer cells on the permeability of microvascular endothelial cells (ECs) sheets, allowing circulating cancer cells to extravasate from the circulation to a distal pre-metastatic niche. It is also important to consider biomechanical factors on this communication, such as the friction caused by the blood flow - shear-stress - on the ECs. Exposure of ECs to an in vitro model of shear-stress, simulating the normal microvascular environment, led not only to morphological, functional, and molecular and changes on those cells, but also changed the cell-to-cell junctions. Moreover, shear-stress altered the adhesion of circulating cancer cells to ECs in vitro, a process favorable to the metastasis process. However, it is still not clear the relation between shear-stress and the uptake of EVs on ECs in the context of metastasis. Thus, our goal is to determine the role of EVs sheds by human TN cell line MDA-MB-231 on the preparation of the metastatic niche through the modulation of ECs with or without shear-stress. We will evaluate changes in ECs morphology by contrast-phase microscopy, modulation in the uptake of EVs by transmission electron microscopy; comparative analysis of proteins from the plasma membrane and EVs by proteomics, investigating possible interactions and possible inhibition targets in silico. Through this project, we expect to develop novel strategies to inhibit the mechanism of invasion and metastasis in TN, increasing the prognosis and overall survival of patients in the future. (AU)