title: Proteinase-activated receptor 2 promotes TGF-β-dependent cell motility in pancreatic cancer cells by sustaining expression of the TGF-β type I receptor ALK5.
abstract: Pancreatic ductal adenocarcinoma (PDAC) is characterized by high expression of transforming growth factor (TGF)-β and the G protein-coupled receptor proteinase-activated receptor 2 (PAR2), the latter of which functions as a cell-surface sensor for serine proteinases asscociated with the tumour microenvironment. Since TGF-β and PAR2 affect tumourigenesis by regulating migration, invasion and metastasis, we hypothesized that there is signalling crosstalk between them. Depleting PDAC and non-PDAC cells of PAR2 by RNA interference strongly decreased TGF-β1-induced activation of Smad2/3 and p38 mitogen-activated protein kinase, Smad dependent transcriptional activity, expression of invasion associated genes, and cell migration/invasion in vitro. Likewise, the plasminogen activator-inhibitor 1 gene in primary cultures of aortic smooth muscle cells from PAR2-/- mice displayed a greatly attenuated sensitivity to TGF-β1 stimulation. PAR2 depletion in PDAC cells resulted in reduced protein and mRNA levels of the TGF-β type I receptor activin receptor-like kinase 5 (ALK5). Forced expression of wild-type ALK5 or a kinase-active ALK5 mutant, but not a kinase-active but Smad-binding defective ALK5 mutant, was able to rescue TGF-β1-induced Smad3 activation, Smad dependent transcription, and cell migration in PAR2-depleted cells. Together, our data show that PAR2 is crucial for TGF-β1-induced cell motility by its ability to sustain expression of ALK5. Therapeutically targeting PAR2 may thus be a promising approach in preventing TGF-β-dependent driven metastatic dissemination in PDAC and possibly other stroma-rich tumour types.
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Zeeh
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Witte
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gädeken
authors.affiliation: Department of General Pharmacology, Institute of Pharmacology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Rauch
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Evelin
authors.initials: E
authors.lastname: Grage-Griebenow
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Nadja
authors.initials: N
authors.lastname: Leinung
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Sofie Joline
authors.initials: SJ
authors.lastname: Fromm
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Stölting
authors.affiliation: Department of Physiology & Pharmacology and Department of Medicine, Inflammation Research Network-Snyder Institute for Chronic Diseases, University of Calgary, Cumming School of Medicine, Calgary, AB, Canada.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Mihara
authors.affiliation: Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Kaufmann
authors.affiliation: Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany.
authors.forename: Utz
authors.initials: U
authors.lastname: Settmacher
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Lehnert
authors.affiliation: Department of Physiology & Pharmacology and Department of Medicine, Inflammation Research Network-Snyder Institute for Chronic Diseases, University of Calgary, Cumming School of Medicine, Calgary, AB, Canada.
authors.forename: Morley D
authors.initials: MD
authors.lastname: Hollenberg
authors.affiliation: First Department of Medicine, University of Lübeck, Lübeck, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Ungefroren
mesh_terms: D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002465:Cell Movement / Q000235:genetics*; D002478:Cells, Cultured; D015972:Gene Expression Regulation, Neoplastic; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009362:Neoplasm Metastasis; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D044464:Receptor, PAR-2; D000077293:Receptor, Transforming Growth Factor-beta Type I; D043562:Receptors, G-Protein-Coupled / Q000502:physiology*; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: C000621508:F2RL1 protein, human; D044464:Receptor, PAR-2; D043562:Receptors, G-Protein-Coupled; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human; C000625842:Tgfbr1 protein, mouse
keywords: ALK5; PAR2; TGF-β; cell motility; signalling