When the Sphingosine Kinase 1/Sphingosine 1-Phosphate Pathway Meets Hypoxia Signaling: New Targets for Cancer Therapy

The reduction in the normal level of tissue oxygen tension or hypoxia is a characteristic of solid tumors that triggers the activation of signaling pathways promoting neovascularization, metastasis, increased tumor growth, and resistance to treatments. The activation of the transcription factor hypoxia-inducible factor 1 alpha (HIF-1 alpha) has been identified as the master mechanism of adaptation to hypoxia. In a recent study, we identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway, which elicits various cellular processes including cell proliferation, cell survival, or angiogenesis, as a new modulator of HIF-1 alpha activity under hypoxic conditions. Here, we consider how the SphK1/S1P signaling pathway could represent a very important target for therapeutic intervention in cancer. [Cancer Res 2009;69(9):3723-6]