Inibição do cross-talk entre alfa (v) beta (3) e VEGFR2 na angiogênese pela desintegrina DisBa-01

Abstract

Angiogenesis, a process by which new capillaries are formed from pre-existing vasculature, is essential in both physiological and pathological conditions. Inadequate balance between pro and antiangiogenic factors can contribute to the progression of tumors and development of metastases. The αvβ3 integrin is considered an angiogenic regulatory receptor due to its cross-talk with vascular endothelial growth factor receptor 2 (VEGFR2). Understanding how these components functionally interact as angiogenic repressors is crucial for the identification of new therapeutic strategies. Disintegrins comprise a family of low molecular weight, cystein-rich peptides from snake venoms that specifically bind to integrins, inhibiting their functions. DisBa-01, a recombinant RGD (Arginine - Glycine - Aspartic acid)-disintegrin from Bothrops alternatus venom, has high affinity for αvβ3, exhibiting anti-metastatic and anti-angiogenic properties. However, its role in the cross-talk between β3 integrin and VEGFR2 in addition to its involvement in downstream signaling pathways, has not been explored. The present study has shown in vitro evidences regarding the direct association between DisBa-01 and the β3/VEGFR2 complex in human umbilical endothelial cells. DisBa-01 inhibited VEGF-induced viability, migration, invasion, adhesion to vitronectin and tubulogenesis, thus decreasing the angiogenic response. DisBa-01 treatment did not affect β3 expression, however, it decreased VEGFR2 protein expression. VEGF-mediated phosphorylation of both receptors was inhibited, causing downregulation of ERK1/2 and PI3K signaling pathways. DisBa-01 positively regulated FAK/Src/Paxillin downstream signal, affecting actin cytoskeleton reorganization, cell migration and adhesion. In conclusion, DisBa-01 impairs the β3/VEGFR2 cross-talk in HUVECs, which interferes in the signaling pathways of ERK1/2, PI3K, FAK, Src and Paxillin, resulting in anti-angiogenic action and cellular morphological alterations. Moreover, these results indicate a strong regulatory role of αvβ3 integrin on VEGF-induced angiogenesis.