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Abstract #2791

Modulations of Intra and Extracellular PH in Tumor Variants Defective in Either Respiration or Glycolysis, Observed by in Vivo MRS

Norbert W. Lutz1, Johanna Chiche2, Yann Le Fur1, Christophe Vilmen1, Frdric Frassineti3, Laurent Daniel3, Jacques Pouyssgur2, Patrick J. Cozzone1

1CRMBM UMR 6612 CNRS, Aix-Marseille University, Medical School, Marseille, PACA, France; 2Institute of Developmental Biology and Cancer Research CNRS UMR 6543, Centre A. Lacassagne, Nice; 3Inserm UMR 911-CRO2, Aix-Marseille University, Medical School

The current use of angiogenesis inhibitors for cancer treatment requires further modifications of the hypoxic tumor microenvironment to achieve complete tumor regression. To contribute to the development of a new treatment strategy, we investigated effects of modulations of multiple mechanisms of glycolytic activity and pH regulation on intracellular and extracellular pH (pHi, pHe) by 31P NMR spectroscopy of tumor xenografts in nude mice. Three ras-transformed fibroblast variants were compared: wild-type CCL39, and mutants defective in either glycolysis or respiration. Compared to CCL39, pHi was increased in either mutant, and pHe was less heterogenous due to a reduction of low-pHe regions.