Clinical Impact of Sphingosine-1-Phosphate in Breast Cancer

Figure 3

The role of sphingosine-1-phosphate (S1P) in estrogen receptor- (ER-) positive breast cancer. Binding of estradiol (E2) to ER-α stimulates sphingosine kinase 1 (SphK1) to produce S1P from sphingosine (Sph). S1P is exported out of cancer cells via ATP-binding cassette (ABC) transporter, such as ABCC1 and ABCG2. This S1P activates S1P receptor (S1PR) of cancer cells to stimulate ERK1/2, which contributes to cell proliferation. S1P may also affect the PI3K pathway by activating AKT.