objective: Specific cellular functions mediated by G protein-coupled receptors (GPCR) are often associated with signaling through a particular G protein or β-arrestin. Here we examine signalling through a GPCR, protease-activated receptor 2 (PAR2), in a high-grade serous ovarian cancer cell line (OV90).
methods: Human ovarian cancer tissues (n = 1200) and nine human ovarian cancer cell lines were assessed for PAR2 expression. PAR2 signalling mechanisms leading to cell migration and invasion were dissected using cellular assays, western blots, CRISPR-Cas9 gene knockouts and pharmacological inhibitors of PAR2 and downstream signalling proteins in OV90 cancer cells.
results: PAR2 was significantly overexpressed i... More
objective: Specific cellular functions mediated by G protein-coupled receptors (GPCR) are often associated with signaling through a particular G protein or β-arrestin. Here we examine signalling through a GPCR, protease-activated receptor 2 (PAR2), in a high-grade serous ovarian cancer cell line (OV90).
methods: Human ovarian cancer tissues (n = 1200) and nine human ovarian cancer cell lines were assessed for PAR2 expression. PAR2 signalling mechanisms leading to cell migration and invasion were dissected using cellular assays, western blots, CRISPR-Cas9 gene knockouts and pharmacological inhibitors of PAR2 and downstream signalling proteins in OV90 cancer cells.
results: PAR2 was significantly overexpressed in clinical ovarian cancer tissues and in OV90 ovarian cancer cells. PAR2 agonists, an endogenous protease (trypsin) and a synthetic peptide (2f-LIGRL-NH ), induced migration and invasion of OV90 ovarian cancer cells through activating a combination of Gα , Gα and β-arrestin1/2, but not Gα or Gα . This novel cooperative rather than parallel signalling resulted in downstream serial activation of Src kinases, then transactivation of epidermal growth factor receptor, followed by downstream MEK-ERK1/2-FOS/MYC/STAT3-COX2 signalling. Either a PAR2 antagonist (I-191), CRISPR-Cas9 gene knockouts (PAR2 or Gα proteins or β-arrestin1/2), or inhibitors of each downstream protein attenuated human ovarian cancer cell motility.
conclusions: This study highlights a novel shared signalling cascade, requiring each of Gα , Gα and β-arrestin1/2, for PAR2-induced ovarian cancer cell migration and invasion. This mechanism controlling a cellular function is unusual in not being linked to a specific individual G protein or β-arrestin mediated signalling pathway.
