Disrupting glucose-6-phosphate isomerase fully suppresses the “Warburg effect” and activates OXPHOS with minimal impact on tumor growth except in hypoxia
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Monique Cunha de Padua1,4,*, Giulia Delodi1,*, Milica Vučetić2, Jérôme Durivault2, Valérie Vial2, Pascale Bayer3, Guilhermina Rodrigues Noleto4, Nathalie M. Mazure1, Maša Ždralević1 and Jacques Pouysségur1,2
1Université Côte d’Azur, IRCAN, CNRS, Inserm, Centre A Lacassagne, Nice, France
2Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco
3Université Côte d’Azur, University Hospital Pasteur, Clinical Chemistry Laboratory, Nice, France
4Department of Biochemistry and Molecular Biology, Federal University of Parana, Curitiba, Brazil
*These authors contributed equally to this work
Jacques Pouysségur, email: [email protected]
Maša Ždralević, email: [email protected]
Keywords: glycolysis, OXPHOS, pentose phosphate pathway, glucose-6-phosphate isomerase, tumor growth
Received: July 23, 2017 Accepted: August 23, 2017 Published: September 18, 2017
As Otto Warburg first observed, cancer cells largely favor fermentative glycolysis for growth even under aerobic conditions. This energy paradox also extends to rapidly growing normal cells indicating that glycolysis is optimal for fast growth and biomass production. Here we further explored this concept by genetic ablation of fermentative glycolysis in two fast growing cancer cell lines: human colon adenocarcinoma LS174T and B16 mouse melanoma. We disrupted the upstream glycolytic enzyme, glucose-6-phosphate isomerase (GPI), to allow cells to re-route glucose-6-phosphate flux into the pentose-phosphate branch. Indeed, GPI-KO severely reduced glucose consumption and suppressed lactic acid secretion, which reprogrammed these cells to rely on oxidative phosphorylation and mitochondrial ATP production to maintain viability. In contrast to previous pharmacological inhibition of glycolysis that suppressed tumor growth, GPI-KO surprisingly demonstrated only a moderate impact on normoxic cell growth. However, hypoxic (1% O2) cell growth was severely restricted. Despite in vitro growth restriction under hypoxia, tumor growth rates in vivo were reduced less than 2-fold for both GPI-KO cancer cell lines. Combined our results indicate that exclusive use of oxidative metabolism has the capacity to provide metabolic precursors for biomass synthesis and fast growth. This work and others clearly indicate that metabolic cancer cell plasticity poses a strong limitation to anticancer strategies.
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