title: S1P1 and VEGFR-2 form a signaling complex with extracellularly regulated kinase 1/2 and protein kinase C-alpha regulating ML-1 thyroid carcinoma cell migration.
abstract: Sphingosine 1-phosphate (S1P) and vascular endothelial growth factor receptor 2 (VEGFR-2) signaling have been shown to integrate in many biological processes. The follicular thyroid carcinoma cell line ML-1 expresses VEGFR-2 and secretes substantial amounts of both vascular endothelial growth factor (VEGF)-A and VEGF-C. ML-1 cells also express S1P-receptors (S1P(1-3,5)). S1P is able to phosphorylate VEGFR-2, and inhibiting VEGFR-2 attenuates S1P-induced migration and down-regulates S1P(1) expression in ML-1 cells. In the present study, we focused on the interactions between S1P(1) and VEGFR-2. We show that S1P receptors form complexes with VEGFR-2 and that the S1P(1)/VEGFR-2 complex associates with protein kinase C (PKC)-alpha and ERK1/2. Furthermore, the complex evokes bidirectional signaling since the S1P-induced ERK1/2 phosphorylation is sensitive to VEGFR-2 kinase inhibition and VEGF-A-induced ERK1/2 phosphorylation is sensitive to pertussis toxin treatment as well as S1P(1) small interfering RNA (siRNA) treatment. Both S1P- and VEGF-A-induced haptotaxis is sensitive to pertussis toxin treatment and S1P(1) siRNA treatment. Phosphorylation of ERK1/2 evoked by both VEGF-A and the S1P(1) agonist SEW-2871 is inhibited by PKC-alpha and PKC-betaI siRNA. We hypothesize that VEGFR-2 forms a signaling complex with S1P(1), evoking bidirectional signaling regulating both ERK1/2 phosphorylation and haptotaxis of ML-1 cells.
authors.affiliation: Department of Biosciences, Abo Akademi University, BioCity, Tykistökatu 6, 20520 Turku, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Bergelin
authors.forename: Christoffer
authors.initials: C
authors.lastname: Löf
authors.forename: Sonja
authors.initials: S
authors.lastname: Balthasar
authors.forename: Veronica
authors.initials: V
authors.lastname: Kalhori
authors.forename: Kid
authors.initials: K
authors.lastname: Törnquist
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008246:Lysophospholipids / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D049349:Receptors, Lysosphingolipid / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; D042461:Vascular Endothelial Growth Factor A; C060506:sphingosine 1-phosphate; D040301:Vascular Endothelial Growth Factor Receptor-2; D051571:Protein Kinase C-alpha; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013110:Sphingosine