EDN1 and ovarian cancer: To investigate ET-1 as a candidate soluble mediator affecting CAF behavior and the involvement of β-arr1, we used human primary fibroblasts derived from the normal ovary (HOFs), characterized by the lower basal expression of fibroblast activation markers, such as α-SMA, vimentin, confirming their inactivated phenotype, compared to ovarian cancer-associated fibroblasts (CAFs) (Supplementary Fig. 1A).