RT Journal Article
SR Electronic
T1 Transforming Growth Factor-<em>β</em>1/Activin Receptor-like Kinase 5-Mediated Cell Migration is Dependent on the Protein Proteinase-Activated Receptor 2 but not on Proteinase-Activated Receptor 2-Stimulated G<sub>q</sub>-Calcium Signaling
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 519
OP 532
DO 10.1124/mol.117.109017
VO 92
IS 5
A1 Hendrik Ungefroren
A1 David Witte
A1 Koichiro Mihara
A1 Bernhard H. Rauch
A1 Petra Henklein
A1 Olaf Jöhren
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/92/5/519.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. Here, we show in the same cells that, conversely, the type I TGF-β receptor activin receptor-like kinase 5 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.