Selective Elimination of Human Pluripotent Stem Cells by an Oleate Synthesis Inhibitor Discovered in a High-Throughput Screen

Abstract

The use of human pluripotent stem cells (hPSCs) in cell therapy is hindered by the tumorigenic risk from residual undifferentiated cells. Here we performed a high-throughput screen of over 52,000 small molecules and identified 15 pluripotent cell-specific inhibitors (PluriSIns), nine of which share a common structural moiety. The PluriSIns selectively eliminated hPSCs while sparing a large array of progenitor and differentiated cells. Cellular and molecular analyses demonstrated that the most selective compound, PluriSIn #1, induces ER stress, protein synthesis attenuation, and apoptosis in hPSCs. Close examination identified this molecule as an inhibitor of stearoyl-coA desaturase (SCD1), the key enzyme in oleic acid biosynthesis, revealing a unique role for lipid metabolism in hPSCs. PluriSIn #1 was also cytotoxic to mouse blastocysts, indicating that the dependence on oleate is inherent to the pluripotent state. Finally, application of PluriSIn #1 prevented teratoma formation from tumorigenic undifferentiated cells. These findings should increase the safety of hPSC-based treatments.

Preclinical Studies for Induced Pluripotent Stem Cell-based Therapeutics

“…Development of highly sensitive methods for detection and efficient separation of undifferentiated cells will be needed (86,87). Among new methods potentially limiting the tumorigenicity of iPSCs are increasing the copy number of tumor suppressors (88) and the use of specific drugs such as metformin (89) and pluripotent cell-specific inhibitors (90).…”

Emerging innovation towards safety in the clinical application of ESCs and iPSCs

“…4 Secondly, chem ical inhibitors of oleate synthesis have been identified as compounds for selective elimination of human ESCs or iPSCs. 6 9 however, in this study only mouse iPSCs were investigated. Metformin, an agonist of AMPactivated protein kinase, suppresses the expression of Oct4 and survivin thereby showing previously unrecognized stemcell toxicity.…”

Hurdles to clinical translation of human induced pluripotent stem cells

“…In addition, these reporters act as suicide genes for tumor ablation therapy by inducing sensitivity to antiviral drugs such as ganciclovir (32,33). In addition, several small molecules have been identified to eliminate human PSCs and prevent teratoma formation; use of these compounds may soon increase the safety profile of stem cell-based treatments (34,35). Ultimately, only long-term studies of the transplanted cell products will be able to accurately assess the tumorigenesis risk associated with such therapies.…”