Sphingosine kinase is an enzyme that is found in the plasma membrane (wall) of the cell. One of its key roles is to initiate signals that result in the cell making factors that help keep the cell alive. These factors do this by blocking the action of death receptors.

Death receptors are proteins that occur on the surface of all cells. They are constantly receiving signals that instruct our cells to die. This happens to the extent that death is the normal default situation for our cells. In this way, the body is able to constantly remodel tissues and organs, replacing aging or damaged cells with new, healthy cells.

Once activated, the death receptors send chemical signals to structures within the cell that contain proteolytic enzymes known as 'caspases'. These caspases digest the proteins within the cell, resulting in the death of the cell. This process is known as apoptosis.

To overcome these constant death signals, the cell makes specific blocking proteins. These proteins absorb the signals coming from the activated death receptors, and in this way the caspases are not activated. The blocking proteins are compounds such as c-FLIP and XIAP.

The signals to the cell to make these blocking factors come from sphingosine kinase via a signaling pathway known as Akt.

In cancer cells, sphingosine kinase activity is increased dramatically, resulting in high levels of c-FLIP and XIAP. The source of this increased activity is thought to be an up-stream regulator, tentatively referred to as a 'sphingosine kinase regulator'. This is thought to be an oncogene, meaning that it is only expressed in cancer cells.

Phenoxodiol is thought to target this sphingosine kinase regulator oncogene, switching it off, and thereby depriving the cancer cell of its blocking factors. The result is that the death receptors, once activated, are able in turn to activate the caspases and to allow the cancer cell to undergo apoptosis.