Inhibition of an NAD+ Salvage Pathway Provides Efficient and Selective Toxicity to Human Pluripotent Stem Cells

Abstract

Abstract The tumorigenic potential of human pluripotent stem cells (hPSCs) is a major limitation to the widespread use of hPSC derivatives in the clinic. Here, we demonstrate that the small molecule STF-31 is effective at eliminating undifferentiated hPSCs across a broad range of cell culture conditions with important advantages over previously described methods that target metabolic processes. Although STF-31 was originally described as an inhibitor of glucose transporter 1, these data support the reclassification of STF-31 as a specific NAD+ salvage pathway inhibitor through the inhibition of nicotinamide phosphoribosyltransferase (NAMPT). These findings demonstrate the importance of an NAD+ salvage pathway in hPSC biology and describe how inhibition of NAMPT can effectively eliminate hPSCs from culture. These results will advance and accelerate the development of safe, clinically relevant hPSC-derived cell-based therapies. Significance The tumorigenic potential of human pluripotent stem cells (hPSCs) is a major limitation to the widespread use of hPSC derivatives in the clinic. This study provides detailed analyses of cellular metabolic flux to define an efficient strategy for selective hPSC elimination that is effective across many culture conditions and does not have cytotoxic effects on hPSC-derived progeny. Of broad significance to the stem cell and regenerative medicine fields, this study also highlights the importance of examining the effect of in vitro culturing parameters when evaluating the efficacy of hPSC-elimination strategies, especially those that target metabolic processes.