Endothelin-1 drives invadopodia and cross-talk with submesothelial matrix invasion cell through ILK

During the metastatic progression, invading cells might achieve degradation and invasion into the extracellular matrix (ECM) using invadopodia, actin-based protrusions. Several growth factors, among other stimuli, might induce invadopodia, generating signaling cues implicated from the initial steps of anchoring and protein recruitment to the final steps of matrix degradation or structure dissembling. In this context, the endothelin A receptor (ETAR) a drives invadopodia in serous ovarian cancer (SOC) cells through the scaffolding function of β-arrestin1 (β-arr1), although the coordinated signaling network is not fully explored. Growing evidence demonstrated that integrins and associated proteins, such as integrin-linked kinase (ILK), operate in the same subcellular compartments to control invadopodium maturation and ECM degradation. Since endothelin-1 (ET-1) through ETAR regulated by ILK, in this study whether ET-1/β-arr1-driven ILK signaling could provide additional mean to enhance invadopodium activity in ovarian cancer progression. We found that β-arr1 functions as a linker for ILK/βPIX (Pax-interacting exchange factor beta) complex, required for activation of Rac3 GTPase, emerging at a crossroad between adhesion and proteolytic signaling, resulting to be overexpressed in tumour compared normal ovarian tissues. Rac3 operates the phosphorylation of PAK1 and cofilin, and regulates invadopodia-dependent ECM degradation and invasion. Moreover, ETAR/ILK/Rac3-dependent signaling supports the communication of SOC cells with mesothelial cells, favouring adhesion and transmigration to. In vivo, ambrisentan, an ETAR antagonist, inhibits the adhesion of HG-SOC cells to intraperitoneal organs, and their spreading, associated with a reduction of invadopodia markers. Finally, high ETAR/ILK expression positively correlates with poor prognosis, representing SOC prognostic factors. Our findings uncover a paradigm indicating where ET-1R/β-arr1/ILK pathway integrates adhesive and proteolytic signaling to invadopodia-mediated ECM degradation, favouring cancer-stroma interactions and SOC metastatic behaviour. Citation Format: Ilenia Masi, Valentina Caprara, Francesca Spadaro, Lidia Chellini, Rosanna Sestito, Andrea Zancla, Alberto Rainer, Anna Bagnato, Laura Rosano. Endothelin-1 drives invadopodia and cross-talk with submesothelial matrix invasion cell through ILK [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr LT003.