Pulsed stable isotope-resolved metabolomic studies of cancer cells.

Metabolic reprogramming is a key step in oncogenic transformation, and it involves alterations in both bioenergetic and anabolic metabolism. Sustained by these metabolic alterations, malignant cells acquire the ability to re-enter the cell cycle and proliferate. The so-called central carbon metabolism (CCM) is the ultimate source for energy and building blocks enabling cellular growth and proliferation. The time-resolved monitoring of the conversion of stable isotope-labeled metabolites provides profound insights into the metabolic dynamics of malignant cells and enables the tracking of individual carbon routes within the CCM. Specifically, the analysis of isotope incorporation rates within short time frames by means of pulsed stable isotope-resolved metabolomics (pSIRM) can be used to determine the dynamics of glycolysis and glutaminolysis-two metabolic circuitries that are often deregulated in malignant cells. Here, we detail a pSIRM-based method that can be applied to the study of metabolic alteration in cultured cancer cells.