Integrin-mechanosignaling role in small GTPases activation and cancer

COLO G.P.; FERNANDEZ CHAVEZ L; SCHWEITZER K; BARRERA LAMAS N; GANDINI NA; ALONSO EG; MASCARO M; PICHEL P; RECIO S; FASSLER R; FACCHINETTI MM; CURINO AC

Mar del Plata

Congreso; LXIV Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2019

Sociedad Argentina de Investigación Clínica (SAIC)

The ability of cells to adhere and simultaneously probe their mechanical environment is central tomany physiological and pathological processes. Extracellular matrix sensing and mechanotransduction are mediated by the integrin family of cell adhesion receptors. Using genetically engineered cells, we studied the specific fibronectin integrin binding signaling and its role in tumor development. We observedthat a5ß1-integrins promoted the formation of small adhesions, low RhoA activation and high force, while aß3-expressing cells showed large adhesions, thick stress fibers, high RhoA activation and low force. To further analyse these cellular phenotypes, we looked for specific RhoA activators (GEFs). For this purpose, we performed Mass Spectrometry (MS) analysis follow by biochemical assays and observed that GEF-H1 activation is aVß3-integrin dependent. Furthermore, using integrin-tail pull-down and MS assay, we observed that GEF-H1 binds to ß3-tail, suggesting that specific integrins may activate different Rho-GEFs during tumor progression. In order to study the role of GEF-H1 in cancer, we analysed by immunohistochemistry GEF-H1 expression in human biopsies. We observed overexpression of GEF-H1 in breast (p=0.0053, n= 61) and thyroid (p= 0.0006, n= 32) tumor biopsies compared with normal tissue. Similar results were obtained in cancer cell lines (CCL). To further study the role of GEF-H1 in tumor development using CRISPR/Cas9 technology, we generated GEF-H1-knock out (KO) clones in a murine invasive breast CCL. We observed a decrease in the proliferation, migration and invasion rates (p