iXgene aims to develop therapeutic medicine for intractable diseases by combining the “i” of iPS cells and “gene” of genome editing. Among intractable diseases, malignant brain tumors are some of the most difficult to manage. Resecting malignant brain tumors completely in an operation is extremely challenging, and drug therapy is ineffective due to the blood-brain barrier. Thus, brain tumors have a high recurrence rate, and there is no effective therapy. As an experimental approach, we have transduced suicide genes into iPS cells through genome editing and differentiated them into neural stem cells, which we call “ixgNSC” and are using in transplantation therapies against malignant brain tumors.

The suicide gene expresses an enzyme that converts prodrugs into drugs such as anticancer drugs. It has this name because cells expressing the gene die. By introducing the suicide gene into iPS cell-derived neural stem cells, administering it to the tumors, and also administering prodrugs, we aim to release anticancer drugs at high concentrations to kill brain tumors.
Because neural stem cells can migrate to brain tumors, we expect ixgNSC to penetrate and destroy all tumor cells.

The suicide gene also means we can remove ixgNSC when needed. This is a key point for the clinical application of iPS cell technologies, since tumorigenicity of the transplanted cells is a concern.
Eventually, ixgNSC will be applied to other brain diseases as regenerative medicine along with treating brain cancers.