Role of extracellular vesicle gelatinase in tumour cell invasion in normoxia and hypoxia

Abstract

Breast cancer is the main cause of mortality amongst Brazilian women, especially due to metastasis, in which tumour cells lose adhesion to the tissue, acquire a mesenchymal phenotype and invade adjacent and distant tissues. Cellular invasion is dependent on the interaction between adhesion receptors and extracellular matrix (ECM) components, which is constantly remodelled by tissue cells. MMP, a family of ECM processing enzymes, is highly expressed in carcinogenesis, where gelatinases (MMP-2 and MMP-9) act on basal membrane proteolysis thus starting cellular invasion. MMPs are also secreted in extracellular vesicles (EVs), structures involved in cellular communication that seem to be involved in metastatic progression. When secreted in EVs, MMPs act in a concentrated way to increase cell invasion. Tumour EVs are also highly secreted in hypoxia, a recurrent condition during tumour progression, but little is known about hypoxia effect on tumour EV protein composition. Through protein detection methods (Western blot, immunoprecipitation and proteomic analysis) and gelatinase activity detection (gelatin degradation assay and zymography), we seek to identify changes in protein composition on EVs secreted by triple-negative breast cancer cells subjected to hypoxia and normoxia, and to study the contribution of vesicular MMPs on tumour cell invasion. (AU)