Papel das integrinas αvβ3 e α5β1 na migração de células de tumor de mama triplo negativo e células endoteliais em hipóxia

Abstract

Breast tumors show high incidence and mortality for female oncologic cases in 2020. Tumor microenvironment presents several elements, such as extracellular matrix (ECM). ECM proteins bind to cells through receptors such as the integrins that control cellular processes. Patterns of integrin expression are changed in tumor cells compared with non-tumor cells. Thus, integrins are studied as possible targets for cancer treatment and metastases prevention. However, most inhibitor effects described in literature are in normoxia, a different condition that is found in the tumor microenvironment. DisBa-01, recombinant protein from Bothrops alternatus, is an αVβ3 integrin blocker, induces loss of OSSC (Oral Squamous Cell Carcinoma) directionally in fibronectin coating, is anti-angiogenic, and inhibits VEGF and VEGFR2 expression in endothelial cell. Until now, these studies were done in-vitro in normoxia and 2D culture, beyond that interactions with secondaries targets. This project studied the effect of blocking αVβ3 integrin treated with DisBa-01 in breast tumor cells (MDA-MB-231) and endothelial cells (HUVEC) in 2D and 3D cultures under hypoxia. We analyzed possible interactions between DisBa-01, ECM proteins and VEGF-R2. We used migratory models including Boyden chamber, endothelial transmigration, wound healing assay treated with DisBa-01. DisBa-01 induced similar effects in normoxia and hypoxia in transwell migration and endothelial transmigration for MDA-MB-231 cells. For wound healing assays, higher concentrations of DisBa-01 were necessary for migration inhibition. DisBa-01 (1000 nM) inhibits tube formation, transwell migration and wound healing assay under hypoxia. For 3D culture, migration inhibition from compact aggregates produced by MDA-MB-231 cell and spheroid produced by HUVEC are similar in both oxygenations treated with DisBa-01. DisBa-01 binds to fibronectin (FN), vitronectin (VN) and VEGFR2 with lower affinity compared with αVβ3 integrin. DisBa-01-αVβ3 integrin-complex interaction colocalizes with FN and VN in HUVEC. These results show that αVβ3 integrin function in cellular motility depends on the assay and oxygenation condition, and higher concentration of inhibitor to cause the same effect in normoxia.