ROLE OF RHOA-ACTIVATOR IN BREAST CANCER

FERNÁNDEZ CHÁVEZ, L.; PERÓS, I.G.; SCHWEITZER, K.; ALONSO, E.G.; GANDINI, N.A.; FACCHINETTI, M.M.; CURINO, A.C.; COLÓ, G.P.

Congreso; Reunión Anual de Sociedades de Biociencia; 2020

Cells express different classes of fibronectin (FN)-binding integrins, which induce signalling pathways that integrate Rho-GTPases to convert integrin signals into specific effector functions. The aim of this work is to study the relationship between differential expression of integrins and specific activation of Rho-GTPases in cancer. Using genetically engineered cells, we observed that α5β1-integrins promoted the formation of small adhesions and low RhoA activation, while αVβ3-expressing cells showed large adhesions, thick stress fibers and high RhoA activation. To further analyse these cellular phenotypes, we looked for specific RhoA activators (GEFs). For this purpose, we performed Mass Spectrometry analysis follow by biochemical assays and observed that GEF-H1 activation is αVβ3-integrin dependent.By bioinformatic analysis using a mRNA dataset (Oncomine) we found high GEF-H1 expression in human breast cancer compared with non-tumoral breast tissue. In addition, high GEF-H1 expression correlated with a lower patient survival (n= 65, p=0.0071). We also observed by immunohistochemistry a significant GEF-H1 over-expression in human breast cancer biopsies compared with normal tissue (n=72, p=0.0201). Furthermore, GEF-H1 protein expression levels correlate with the invasive potential of human and murine breast cancer cell lines. Using CRISPR/Cas9 technology, we generated GEF-H1-knock out (KO) clones in a murine invasive breast cancer cell. We observed a significant decrease in the proliferation, migration and invasion rates in GEF-H1-KO cells (p