Role of RhoA-activator in breast cancer progression

FERNÁNDEZ CHÁVEZ L; PEROS IG; SCHWEITZER K; ALONSO, EG; GANDINI NA; FACCHINETTI MM; CURINO AC; COLÓ GP

Bahia Blanca

Congreso; REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACION CLINICA; 2020

Sociedad Argentina de Investigación Clínica

Cells express different classes of fibronectin (FN)-binding integrins,which induce signalling pathways that integrate Rho-GTPases toconvert integrin signals into specific effector functions. The aim ofthis work is to study the relationship between differential expressionof integrins and specific activation of Rho-GTPases in cancer. Usinggenetically 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 stressfibers and high RhoA activation. To further analyse these cellularphenotypes, we looked for specific RhoA activators (GEFs). For thispurpose, 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) wefound highGEF-H1 expression in human breast cancer comparedwith non-tumoral breast tissue. In addition, high GEF-H1 expressioncorrelated with a lower patient survival (n= 65, p=0.0071). We alsoobserved 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 expressionlevels correlate with the invasive potential of human and murinebreast cancer cell lines. Using CRISPR/Cas9 technology, we generated GEF-H1-knock out (KO) clones in a murine invasive breastcancer cell. We observed a significant decrease in the proliferation,migration and invasion rates in GEF-H1-KO cells (p