Anthon Mancuso1, Stephen Kadlecek2, Robert V. Cadman2, Matthew A. Stetz2, Roland Knoblauch1, Craig B. Thompson, Rahim Rizi2
1Cancer Biology, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA
Glutamine is a critical metabolite for the rapid growth of many cancer cell types. We examined the metabolism of hyperpolarized [1-13C]pyruvate in mouse mammary tumor cells in culture medium with and without glutamine. Lactate was the predominant end product and very little labeled alanine was observed, which was surprising since normally these cells produce significant amounts of alanine from glucose. Another interesting finding was that lactate was reduced when pyruvate plus NH4Cl was substituted for glutamine suggesting that omitting glutamine was not compensated for with increased flux through lactate dehydrogenase (and presumably glycolysis). Lastly, no metabolites were observed that would suggest pyruvate carboxylase is active. Thus, the primary effect of omitting glutamine from the medium would appear to be an overall reduction in metabolic activity.