A Double Fail-Safe Approach to Prevent Tumorigenesis and Select Pancreatic β Cells from Human Embryonic Stem Cells

The transplantation of human embryonic stem cell (hESC)-derived insulin-producing β cells for the treatment of diabetes is finally approaching the clinical stage. However, even with state-of-the-art differentiation protocols, a significant percentage of undefined non-endocrine cell types are still generated. Most importantly, there is the potential for carry-over of non-differentiated cell types that may produce teratomas. We sought to modify hESCs so that their differentiated progeny could be selectively devoid of tumorigenic cells and enriched for cells of the desired phenotype (in this case, β cells). Here we report the generation of a modified hESC line harboring two suicide gene cassettes, whose expression results in cell death in the presence of specific pro-drugs. We show the efficacy of this system at enriching for β cells and eliminating tumorigenic ones both in vitro and in vivo. Our approach is innovative inasmuch as it allows for the preservation of the desired cells while eliminating those with the potential to develop teratomas. [Display omitted] •hESCs were engineered with suicide genes for safety and differentiation efficiency•One cassette is exclusively expressed in teratogenic cells (safety)•Another is selectively excised out in hESC-derived pancreatic β cells (selectivity)•Our strategy allows for hESC-derived tumors to be prevented or ablated in vivo In this article, Domínguez-Bendala and colleagues present a strategy to modify pluripotent stem cells to allow for the selective destruction of tumorigenic escapees and/or fully developed teratomas, as well as for the specific selection of differentiated insulin-producing β-like cells. Cells engineered in this manner feature a double fail-safe mechanism designed to minimize the risks associated with their clinical transplantation.