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Cellular & Molecular Biology Letters

Open Access

The effects of markedly raised intracellular sphingosine kinase-1 activity in endothelial cells

  • Vidya Limaye1, 2, 3Email author,
  • Mathew A. Vadas4,
  • Stuart M. Pitson2, 5 and
  • Jennifer R. Gamble4
Cellular & Molecular Biology LettersAn International Journal200914:8

Received: 15 July 2008

Accepted: 12 February 2009

Published: 23 February 2009


The enzyme sphingosine kinase-1 (SK1) promotes the formation of sphingosine-1-phosphate (S1P), which is an important survival factor for endothelial cells (EC). Modest increases in intracellular SK1 activity in the EC are known to confer a survival advantage upon the cells. Here, we investigated the effects of more dramatic increases in intracellular SK1 in the EC. We found that these cells show reduced cell survival under conditions of stress, enhanced caspase-3 activity, cell cycle inhibition, and cell-cell junction disruption. We propose that alterations in the phosphorylation state of the enzyme may explain the differential effects on the phenotype with modest versus high levels of enforced expression of SK1. Our results suggest that SK1 activity is subject to control in the EC, and that this control may be lost in conditions involving vascular regression.

Key words

Sphingosine kinase-1Endothelial cellsCell survival