Evaluation of sulfur isotopic enrichment of urine metabolites for the differentiation of healthy and prostate cancer mice after the administration of 34S labelled yeast

Sulfur isotopic enrichment of urine metabolites in healthy and prostate cancer mice using 34S enriched yeast and High Performance Liquid Chromatography coupled to Multicollector Inductively Coupled Plasma Mass Spectrometry (HPLC-MC-ICP-MS) has been evaluated. A 30 weeks experiment (since the eleventh to the fortieth week of life) was carried out collecting the urine of three healthy mice and three transgenic mice with prostate cancer during 24h after a single oral administration of a 34S enriched yeast slurry. The isotopic enrichment of different sulphur metabolites was monitored by coupling a C18 reverse phase HPLC column with a multicollector ICP-MS using a membrane desolvating system. Quantification of sulfur in the chromatographic peaks was carried out by post-column isotope dilution using a 33S enriched spike. Differences between the 34S enrichment in the urine metabolites of healthy and prostate cancer mice were found from the beginning of the disease. Both populations could be differentiated using a principal component analysis (PCA). Finally, 7 unknown mice were correctly classified in each population using a linear discriminant analysis.