title: PAR1-mediated RhoA activation facilitates CCL2-induced chemotaxis in PC-3 cells.
abstract: Patients with advanced prostate cancer often exhibit increased activation of the coagulation system. The key activator of the coagulation cascade is the serine protease thrombin which is capable of eliciting numerous cellular responses. We previously reported that the thrombin receptor PAR1 is overexpressed in prostate cancer. To investigate further the role of PAR1 in prostate cancer metastasis, we examined the effects of thrombin activation on cell adhesion and motility in PC-3 prostate cancer cells. Activation of PAR1-induced dynamic cytoskeletal reorganization and reduced PC-3 binding to collagen I, collagen IV, and laminin (P < 0.01) but not fibronectin. Expression of the cell surface integrin receptors did not change as assessed by flow cytometry. Immunofluorescence microscopy revealed that PAR1 stimulation caused reorganization of the focal adhesions, suggesting that PAR1 activation in PC-3 cells may be modulating cell adhesion through integrin function but not expression. Furthermore, RhoA was activated upon stimulation with thrombin with subsequent cell contraction, decreased cell adhesion, and induced migration towards monocyte chemoattractant protein 1 (MCP-1; CCL2). Thus, it appears that thrombin stimulation plays a role in prostate cancer metastasis by decreasing cell adhesion to the extracellular matrix and positioning the cell in a "ready state" for migration in response to a chemotactic signal. Further exploration is needed to determine whether PAR1 activation affects other signaling pathways involved in prostate cancer.
authors.affiliation: Department of Urology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA. rloberg@umich.edu
authors.forename: Robert D
authors.initials: RD
authors.lastname: Loberg
authors.forename: Kwanchanit
authors.initials: K
authors.lastname: Tantivejkul
authors.forename: Matthew
authors.initials: M
authors.lastname: Craig
authors.forename: Chris K
authors.initials: CK
authors.lastname: Neeley
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Pienta
mesh_terms: D000199:Actins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000187:drug effects; D018932:Chemokine CCL2 / Q000494:pharmacology*; D002633:Chemotaxis / Q000187:drug effects*; D003599:Cytoskeleton / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005109:Extracellular Matrix / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D016023:Integrins / Q000378:metabolism; D008297:Male; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology*; D044463:Receptor, PAR-1 / Q000378:metabolism*; D013917:Thrombin / Q000494:pharmacology; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000199:Actins; D018932:Chemokine CCL2; D016023:Integrins; D044463:Receptor, PAR-1; D013917:Thrombin; D020764:cdc42 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein