Sphingosine kinase 1 in cancer.

The role of sphingolipids as bioactive signaling molecules that can regulate cell fate decisions puts them at center stage for cancer treatment and prevention. While ceramide and sphingosine have been established as antigrowth molecules, sphingosine-1-phosphate (S1P) offers a progrowth message to cells. The enzymes responsible for maintaining the balance between these "stop" or "go" signals are the sphingosine kinases (SK), SK1 and SK2. While the relative contribution of SK2 is still being elucidated and may involve an intranuclear role, a substantial amount of evidence suggests that regulation of sphingolipid levels by SK1 is an important component of carcinogenesis. Here, we review the literature regarding the role of SK1 as an oncogene that can function to enhance cancer cell viability and promote tumor growth and metastasis; highlighting the importance of developing specific SK1 inhibitors to supplement current cancer therapies.