Fail-Safe System against Potential Tumorigenicity after Transplantation of iPSC Derivatives

Area of Science:

• Stem cell biology
• Regenerative medicine
• Gene therapy

Background:

• Human induced pluripotent stem cells (iPSCs) hold great promise for regenerative medicine.
• Tumorigenic risks, including teratoma formation and overgrowth of transplanted cells, are significant barriers to clinical translation.
• A robust safety mechanism is needed to control transplanted cells.

Purpose of the Study:

• To evaluate the efficacy of the inducible caspase-9 (iCaspase9) gene as a safety switch.
• To assess the iCaspase9 system's ability to prevent tumorigenic transformation of iPSC-derived somatic cells.
• To determine the in vitro and in vivo functionality of iCaspase9 in iPSCs and iPSC-derived neural stem/progenitor cells (iPSC-NS/PCs).

Main Methods:

• Lentiviral vector transduction of iCaspase9 into two human iPSC lines.
• In vitro assessment of iCaspase9-mediated apoptosis in iPSCs and iPSC-NS/PCs.
• In vivo transplantation of iPSC-NS/PCs into injured spinal cords of NOD/SCID mice.
• Evaluation of iCaspase9-mediated ablation of transplanted cells impacting motor function recovery.

Main Results:

• The iCaspase9 system induced apoptosis in approximately 95% of both iPSCs and iPSC-NS/PCs in vitro.
• In vivo, transplanted iPSC-NS/PCs that caused mass effect hindering motor recovery were effectively ablated after iCaspase9 induction.
• The iCaspase9 system demonstrated efficient control over transplanted iPSC-derived cells in a preclinical model.

Conclusions:

• The inducible caspase-9 system serves as an effective fail-safe mechanism against undesired cell proliferation.
• This technology offers a promising strategy to mitigate adverse events associated with stem cell transplantation therapies.
• iCaspase9 integration is a vital step towards the safe clinical application of iPSC-based regenerative medicine.