Therapeutic applications of bioactive sphingolipids in hematological malignancies.

Sphingolipids are sphingosine-based lipid molecules that have important functions in cellular signal transduction and in a variety of cellular processes including proliferation, differentiation, programmed cell death (apoptosis) and responses to stressful conditions. Ceramides, dihydroceramide, sphingosine and sphingosine-1-phosphate are examples of those bioactive sphingolipids. They have a major impact on determination of the cell fate by contributing to the cell survival or cell death through apoptosis. Despite the number of carbon atoms in the fatty acid chain changes the physiological role; ceramides generally exert suppressive roles on the cell proliferation. There have been several enzymes identified in this pathway that are responsible for the conversion of ceramide into other sphingolipid derivatives. Those derivatives also have differential roles on those cellular processes. Sphingosine-1-phosphate is an example of such sphingolipid derivatives which has antiapoptotic effects. As they have significant impacts particularly on the cell death and survival, bioactive sphingolipids have a great potential to be targets in cancer therapy. Increasing number of studies indicates that sphingolipid derivatives are important in the progression of hematological malignancies, and they are also involved in the resistance to current chemotherapeutic options. This review compiles the current knowledge in this area for enlightening the therapeutic potentials of bioactive sphingolipids in various leukemias.