Endothelin-1 induces tumor proteinase activation and invasiveness of ovarian carcinoma cells

Endothelin-1 (ET-1) is present at high concentrations in ovarian cancer asc ites and is overexpressed. in primary and metastatic ovarian carcinoma. In these cells, ET-I acts as an autocrine mitogenic and angiogenic factor sele ctively through the ETA receptor (ETAR). We investigated at mRNA and protei n levels whether ET-1 could affect the expression and activation of metasta sis-related proteinases and whether this process was associated with ovaria n tumor cell invasion. ELISA, gelatin zymography, Western blot, and reverse transcription-PCR analyses demonstrated that in two ovarian carcinoma cell lines (HEY and OVCA 433), the expression of matrix metalloproteinase (MMP) -2. -9, -3, -7, and -13 was up-regulated and activated by ET-1. Moreover w e observed that ET-1 was able to enhance the secretion and activation of me mbrane-type metalloproteinase-1, a critical mediator of invasiveness. The s ecretion of tissue inhibitor of metalloproteinase-1 and -2 was decreased by ET-1, which increased the net MMP/tissue inhibitor of metalloproteinase ba lance and the gelatinolytic capacity. In addition, ET-1 induced overexpress ion of urokinase-type plasminogen activator, its receptor, and plasminogen activator inhibitor type-1 and -2. Finally, we demonstrated that, in HEY an d OVCA 433 cells, ET-1 dose-dependently increased migration and MMP-depende nt invasion through Matrigel. BQ123, an antagonist of the ETAR, inhibited t he ET-1-induced tumor protease activity and subsequent increase in cell mig ration and invasion. These findings demonstrate that ET-1 promotes ovarian carcinoma cell invasion, acting through the ETAR by up-regulating secretion and activation of multiple tumor proteinases. Therefore, ET-1 may represen t a key component of more aggressive ligand-induced invasiveness of ovarian carcinoma.