Authors: Alejandro Vazquez-Martin, Luciano Vellon, Pedro M. Quirós, Sílvia Cufí, Eunate Ruiz de Galarreta, Cristina Oliveras-Ferraros, Angel G. Martin, Begoña Martin-Castillo, Carlos López-Otín and Javier A. Menendez

Alejandro Vazquez-Martin

Translational Research Laboratory; Catalan Institute of Oncology (ICO); Girona, Spain; Girona Biomedical Research Institute (IDIBGi); Girona, Spain

Luciano Vellon

Cell Reprogramming Unit; Fundación INBIOMED; San Sebastián, Gipuzkua, Spain; These authors have equally contributed to this research and are listed in random order.

Pedro M. Quirós

Departamento de Bioquímica y Biología Molecular; Facultad de Medicina; Instituto Universitario de Oncología; Universidad de Oviedo; Oviedo, Spain

Sílvia Cufí

Translational Research Laboratory; Catalan Institute of Oncology (ICO); Girona, Spain; Girona Biomedical Research Institute (IDIBGi); Girona, Spain

Eunate Ruiz de Galarreta

Cell Reprogramming Unit; Fundación INBIOMED; San Sebastián, Gipuzkua, Spain

Cristina Oliveras-Ferraros

Translational Research Laboratory; Catalan Institute of Oncology (ICO); Girona, Spain; Girona Biomedical Research Institute (IDIBGi); Girona, Spain

Angel G. Martin

Regulation of Cell Growth Laboratory; Fundación INBIOMED; San Sebastián, Gipuzkua, Spain

Begoña Martin-Castillo

Unit of Clinical Research; Catalan Institute of Oncology (ICO); Girona, Spain

Carlos López-Otín

Departamento de Bioquímica y Biología Molecular; Facultad de Medicina; Instituto Universitario de Oncología; Universidad de Oviedo; Oviedo, Spain

Javier A. Menendez

Corresponding author: jmenendez@iconcologia.net, jmenendez@idibgi.org
Translational Research Laboratory; Catalan Institute of Oncology (ICO); Girona, Spain; Girona Biomedical Research Institute (IDIBGi); Girona, Spain

The ability of somatic cells to reprogram their ATP-generating machinery into a Warburg-like glycolytic metabotype while overexpressing stemness genes facilitates their conversion into either induced pluripotent stem cells (iPSCs) or tumor-propagating cells. AMP-activated protein kinase (AMPK) is a metabolic master switch that senses and decodes intracellular changes in energy status; thus, we have evaluated the impact of AMPK activation in regulating the generation of iPSCs from nonstem cells of somatic origin. The indirect and direct activation of AMPK with the antidiabetic biguanide metformin and the thienopyridone A-769662, respectively, impeded the reprogramming of mouse embryonic and human diploid fibroblasts into iPSCs. The AMPK activators established a metabolic barrier to reprogramming that could not be bypassed, even through p53 deficiency, a fundamental mechanism to greatly improve the efficiency of stem-cell production. Treatment with metformin or A-769662 before the generation of iPSC colonies was sufficient to drastically decrease iPSC generation, suggesting that AMPK activation impedes early stem cell genetic reprogramming. Monitoring the transcriptional activation status of each individual reprogramming factor (i.e., Oct4, Sox2, Klf4 and c-Myc) revealed that AMPK activation notably prevented the transcriptional activation of Oct4, the master regulator of the pluripotent state. AMPK activation appears to impose a normalized metabolic flow away from the required pro-immortalizing glycolysis that fuels the induction of stemness and pluripotency, endowing somatic cells with an energetic infrastructure that is protected against reprogramming. AMPK-activating anti-reprogramming strategies may provide a roadmap for the generation of novel cancer therapies that metabolically target tumor-propagating cells.