ABSTRACT
One major concern over the clinical application of embryonic stem cell (ESC)-derived cells is the potentiation of latent tumorigenicity by residual undifferentiated cells. Despite the use of intensive methodological approaches to eliminate residual undifferentiated cells, the properties of these cells remain elusive. Here, we show that under a serum-free neural differentiation condition, residual undifferentiated cells markedly delay progression of their cell cycle without compromising their pluripotency. This dormant pluripotency was maintained during reculture of the cells under a serum-free condition, whereas upon serum stimulation, the cells exited the dormant state and restarted proliferation and differentiation into all three germ layers. Microarray analysis revealed a set of genes that is significantly upregulated in the dormant ESCs compared with their levels of regulation in proliferating ESCs. Among them, we identified the transcription factor Forkhead box O3 (FoxO3) to be an essential regulator of the maintenance of pluripotency in dormant ESCs. Our study demonstrates that the transition into the dormant state endows residual undifferentiated cells with FoxO3-dependent and leukemia inhibitory factor/serum-independent pluripotency.
Supplemental material for this article may be found at https://doi.org/10.1128/MCB.00417-16.
ACKNOWLEDGMENTS
We thank N. Takata and E. Sakakura (Riken CDB) and M. Maekawa and T. Yamamoto (Kyoto University) for technical guidance, Y. Komatsuzaki (Kyoto University) for technical assistance, and H. Harada (Kyoto University) for critical scientific discussions.
M.I. and F.T. designed the experiments. M.I. performed the experiments. M.I. and F.T. analyzed the data. M.I and F.T. wrote the manuscript.
We have no conflicts of interest to declare.
This work was supported by JSPS KAKENHI grant number 15J05582 (to M.I.), MEXT KAKENHI grant number 26116712 (to F.T.), and the Naito Foundation (to F.T.).