One way in which cancer cells flourish is by concealing themselves against cytotoxic immune cells. Invariant natural killer T (iNKT) cells are rare helper immune cells that activate these cytotoxic cells when cancers go into hiding. Indeed, the level of iNKT cells in the blood is a good predictor of clinical outcome.

Increasing the number of iNKT cells, therefore, could be an effective cell therapy against cancers. Shin Kaneko, Associate Professor at the Center for iPS Cell Research and Application (CiRA) at Kyoto University, Japan, and his team are using induced pluripotent stem (iPS) cell technology to investigate this possibility. In their most recent work they report the preparation of reprogrammed (re-) iNKT cells. These cells come from patient iNKT cells that were reprogrammed to iPS cells and then multiplied before being differentiated to re-iNKT cells, thus significantly increasing the number of iNKT cells from before.

Unexpectedly, although the re-iNKT cells behaved like iNKT cells, they showed properties that deviated from their origin and resulted in more potency. These deviations suggest that re-iNKT cells followed a different development pathway than normal iNKT cells. Such an alternative pathway could open the door to the preparation of different cell types for cancer therapy. Kaneko explains, “Cancer patients usually have severely weakened immune systems. The ability to make potent immune cells is very helpful”.

The creation of potent immune cells also has important implications on our understanding of how immune cells are formed. “The immune system is maybe the most complicated system in the body”, says Kaneko. “Simplifying it may help us develop new treatments”.

The group is now investigating the different pathways in which iNKT cells can be formed and identifying which are best for cancer therapy.