Methods for Metabolic Evaluation of Prostate Cancer Cells Using Proton and 13C HR-MAS Spectroscopy and [3-13C] Pyruvate as a Metabolic Substrate

Prostate cancer has been shown to undergo unique metabolic changes associated with neoplastic transformation, with associated changes in citrate, alanine, and lactate concentrations. C-13 high resolution-magic angle spinning (HR-MAS) spectroscopy provides an opportunity to simultaneously investigate the metabolic pathways implicated in these changes by using C-13-labeled substrates as metabolic probes. In this work, a method to reproducibly interrogate metabolism in prostate cancer cells in primary culture was developed using HR-MAS spectroscopy. Optimization of cell culture protocols, labeling parameters, harvesting, storage, and transfer was performed. Using [3-C-13] pyruvate as a metabolic probe, H-1 and C-13 HR-MAS spectroscopy was used to quantify the net amount and fractional enrichment of several labeled metabolites that evolved in multiple cell samples from each of five different prostate cancers. Average enrichment across all cancers was 32.4 +/- 5.4% for (3-C-13] alanine, 24.5 +/- 5.4% for [4-C-13] glutamate, 9.1 +/- 2.5% for [3-C-13] glutannate, 25.2 +/- 5.7% for [3-C-13] aspartate, and 4.2 +/- 1.0% for [3-C-13] lactate. Cell samples from the same parent population demonstrated reproducible fractional enrichments of alanine, glutannate, and aspartate to within 12%, 10%, and 10%, respectively. Furthermore, the cells produced a significant amount of [4-C-13] glutamate, which supports the bioenergetic theory for prostate cancer. These methods will allow further characterization of metabolic properties of prostate cancer cells in the future. Magn Reson Med 62:1091-1098, 2009. (C) 2009 Wiley-Liss, Inc.