Functional interaction between endothelin-1 and ZEB1/YAP signaling regulates cellular plasticity and metastasis in high-grade serous ovarian cancer

Abstract

Background: Epithelial-to-mesenchymal transition (EMT) encompasses a highly dynamic and complex key process which leads to metastatic progression. In high-grade serous ovarian carcinoma (HG-SOC), endothelin-1 (ET-1)/endothelin A receptor (ET_AR) signaling promotes EMT driving tumor progression. However, the complex nature of intertwined regulatory circuits activated by ET-1 to trigger the metastatic process is not fully elucidated.

Methods: The capacity of ET-1 pathway to guide a critical transcriptional network that is instrumental for metastatic growth was identified in patient-derived HG-SOC cells and cell lines through immunoblotting, q-RT-PCR, co-immunoprecipitation, in situ proximity ligation, luciferase reporter, chromatin immunoprecipitation assays and publicly available databases. Functional assays in HG-SOC cells and HG-SOC xenografts served to test the inhibitory effects of ET-1 receptors (ET-1R) antagonist in vitro and in vivo.

Results: We demonstrated that ET-1/ET_AR axis promoted the direct physical ZEB1/YAP interaction by inducing their nuclear accumulation in HG-SOC cells. Moreover, ET-1 directed their engagement in a functional transcriptional complex with the potent oncogenic AP-1 factor JUN. This led to the aberrant activation of common target genes, including EDN1 (ET-1) gene, thereby creating a feed-forward loop that sustained a persistent ET-1/ZEB1 signaling activity. Notably, ET-1-induced Integrin-linked kinase (ILK) signaling mediated the activation of YAP/ZEB1 circuit driving cellular plasticity, invasion and EMT. Of therapeutic interest, treatment of HG-SOC cells with the FDA approved ET-1R antagonist macitentan, targeting YAP and ZEB1-driven signaling, suppressed metastasis in vivo in mice. High gene expression of ET_AR/ILK/YAP/AP-1/ZEB1 was a strong predictor of poor clinical outcome in serous ovarian cancer patients, indicating the translational relevance of this signature expression.

Conclusions: This study provides novel mechanistic insights of the ET-1R-driven mediators that support the ability of HG-SOC to acquire metastatic traits which include the cooperation of YAP and ZEB1 regulatory circuit paving the way for innovative treatment of metastatic ovarian cancer.

Keywords: AP-1; Endothelin A receptor; Epithelial-to-mesenchymal transition; ILK; Metastasis; Ovarian carcinoma; YAP; ZEB1.