Department of Biosciences, Abo Akademi University, BioCity, Tykistökatu 6, 20520 Turku, Finland.
Endocrinology. 2010 Jul;151(7):2994-3005. doi: 10.1210/en.2009-1387. Epub 2010 May 25.
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.
鞘氨醇 1-磷酸（S1P）和血管内皮生长因子受体 2（VEGFR-2）信号已被证明在许多生物学过程中整合在一起。滤泡甲状腺癌细胞系 ML-1 表达 VEGFR-2 并分泌大量血管内皮生长因子（VEGF）-A 和 VEGF-C。ML-1 细胞还表达 S1P 受体（S1P（1-3,5））。S1P 能够磷酸化 VEGFR-2，并且抑制 VEGFR-2 可减弱 S1P 诱导的迁移，并下调 ML-1 细胞中的 S1P（1）表达。在本研究中，我们专注于 S1P（1）和 VEGFR-2 之间的相互作用。我们表明 S1P 受体与 VEGFR-2 形成复合物，并且 S1P（1）/VEGFR-2 复合物与蛋白激酶 C（PKC）-alpha 和 ERK1/2 相关。此外，该复合物引发双向信号，因为 S1P 诱导的 ERK1/2 磷酸化对 VEGFR-2 激酶抑制敏感，而 VEGF-A 诱导的 ERK1/2 磷酸化对百日咳毒素处理以及 S1P（1）小干扰 RNA（siRNA）处理敏感。S1P 和 VEGF-A 诱导的趋化性对百日咳毒素处理和 S1P（1）siRNA 处理均敏感。VEGF-A 和 S1P（1）激动剂 SEW-2871 诱导的 ERK1/2 磷酸化均被 PKC-alpha 和 PKC-betaI siRNA 抑制。我们假设 VEGFR-2 与 S1P（1）形成信号复合物，引发双向信号，调节 ML-1 细胞中 ERK1/2 磷酸化和趋化性。
