RT Journal Article
SR Electronic
T1 TGF-β1/ALK5-mediated cell migration is dependent on the protein PAR2 but not on PAR2-stimulated Gq-calcium signaling
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.117.109017
DO 10.1124/mol.117.109017
A1 Hendrik Ungefroren
A1 David Witte
A1 Koichiro Mihara
A1 Bernhard H Rauch
A1 Petra Henklein
A1 Olaf Johren
A1 Shirin Bonni
A1 Utz Settmacher
A1 Hendrik Lehnert
A1 Morley D Hollenberg
A1 Roland Kaufmann
A1 Frank Gieseler
YR 2017
UL http://molpharm.aspetjournals.org/content/early/2017/08/25/mol.117.109017.abstract
AB Transforming growth factor-β (TGF-β), serine proteinases such as trypsin, and proteinase-activated receptor 2 (PAR2) promote tumor development by stimulating invasion and metastasis. Previously, we found that in cancer cells derived from pancreatic ductal adenocarcinoma (PDAC) PAR2 protein is necessary for TGF-β1-dependent cell motility (Zeeh et al., 2016). Here, we show in the same cells that, conversely, the type I TGF-β; receptor ALK5 is dispensable for trypsin and PAR2 activating peptide (PAR2-AP)-induced migration. To reveal whether Gq-calcium signaling is a prerequisite for PAR2 to enhance TGF-β signaling, we investigated the effects of PAR2-APs, PAR2 mutation and PAR2 inhibitors on TGF-β1-induced migration, reporter gene activity, and Smad activation. Stimulation of cells with PAR2-AP alone failed to enhance basal or TGF-β1-induced C-terminal phosphorylation of Smad3, Smad-dependent activity of a luciferase reporter gene, and cell migration. Consistently, in complementary loss of function studies, abrogation of the PAR2-Gq-calcium signaling arm failed to suppress TGF-β1-induced cell migration, reporter gene activity, and Smad3 activation. Together, our findings suggest that the calcium-regulating motif is not required for PAR2 to synergize with TGF-β1 to promote cell motility. Additional experiments in PDAC cells revealed that PAR2 and TGF-β1 synergy may involve TGF-β1 induction of enzymes that cause autocrine cleavage/activation of PAR2, possibly through a biased signaling function. Our results suggest that although reducing PAR2 protein expression may potentially block TGF-β's prooncogenic function, inhibiting PAR2-Gq-calcium signaling alone would not be sufficient to achieve this effect.