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

• Published in: Endocrinology (Philadelphia) 2010-07, Vol.151 (7), p.2994-3005
• Main Authors: Bergelin, Nina, Löf, Christoffer, Balthasar, Sonja, Kalhori, Veronica, Törnquist, Kid
• Format: Article
• Language: English
• Subjects: Blotting, Western; Cell Line, Tumor; Cell Movement - drug effects; Cell Movement - genetics; Humans; Immunohistochemistry; Immunoprecipitation; Lysophospholipids - pharmacology; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3 - metabolism; Phosphorylation - drug effects; Protein Binding - drug effects; Protein Binding - genetics; Protein Kinase C-alpha - metabolism; Receptors, Lysosphingolipid - agonists; Receptors, Lysosphingolipid - antagonists & inhibitors; Receptors, Lysosphingolipid - genetics; Receptors, Lysosphingolipid - metabolism; Signal Transduction - drug effects; Signal Transduction - genetics; Sphingosine - analogs & derivatives; Sphingosine - pharmacology; Thyroid Neoplasms - genetics; Thyroid Neoplasms - metabolism; Vascular Endothelial Growth Factor A - pharmacology; Vascular Endothelial Growth Factor Receptor-2 - agonists; Vascular Endothelial Growth Factor Receptor-2 - antagonists & inhibitors; Vascular Endothelial Growth Factor Receptor-2 - metabolism
• ISSN: 1945-7170
• DOI: 10.1210//en.2009-1387

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.