Sphingosine-1-Phosphate Transporters as Targets for Cancer Therapy

Figure 1

“Inside-out” signaling of sphingosine-1-phosphate (S1P). S1P is generated from Sph (sphingosine) by SphK1 (sphingosine kinase 1) in the cytosol of cancer cells and exported via ABC (ATP-binding cassette) transporters or Spns2 (spinster 2) outside of cells (tumor microenvironment). S1P stimulates specific S1P receptors (S1PR1-5) to promote numerous cellular functions, such as cell proliferation, migration, angiogenesis, and lymphangiogenesis.