Sphingosine kinase-1 is a hypoxia-regulated gene that stimulates migration of human endothelial cells.
Sphingosine kinases (SK) catalyze the production of sphingosine-1-phosphate which in turn regulates cell responses such as proliferation and migration. Here, we show that exposure of the human endothelial cell line EA.hy 926 to hypoxia stimulates a increased SK-1, but not SK-2, mRNA, protein expression, and activity. This effect was due to stimulated SK-1 promoter activity which contains two putative hypoxia-inducible factor-responsive-elements (HRE). By deletion of one of the two HREs, hypoxia-induced promoter activation was abrogated. Furthermore, hypoxia upregulated the expression of HIF-1alpha and HIF-2alpha, and both contributed to SK-1 gene transcription as shown by selective depletion of HIF-1alpha or HIF-2alpha by siRNA. The hypoxia-stimulated SK-1 upregulation was functionally coupled to increased migration since the selective depletion of SK-1, but not of SK-2, by siRNAs abolished the migratory response. In summary, these data show that hypoxia upregulates SK-1 activity and results in an accelerated migratory capacity of endothelial cells. SK-1 may thus serve as an attractive therapeutic target to treat diseases associated with increased endothelial migration and angiogenesis such as cancer growth and progression.
Schwalm
Stephanie
S
Pharmazentrum Frankfurt/ZAFES, Klinikum der J.W. Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
Döll
Frauke
F
Römer
Isolde
I
Bubnova
Svetlana
S
Pfeilschifter
Josef
J
Huwiler
Andrea
A
D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000502:physiology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000502:physiology*; D000099157:Sphingosine Kinase; D000099162:Endothelial PAS Domain-Containing Protein 1
D051792:Basic Helix-Loop-Helix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017853:Phosphotransferases (Alcohol Group Acceptor); D000099157:Sphingosine Kinase; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human