Highly sensitive matrix-assisted laser desorption ionization-mass spectrometry for high-throughput metabolic profiling.

In the present study, a high-throughput and nontargeted metabolomic technique using matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) was developed for the rapid analysis of cellular metabolites. Either the detection limit or the linearity between concentrations of several standards and peak intensities was examined, indicating a detection limit lower than 10 fmol/well with a high linearity at low concentrations. To verify the validity of this method, metabolites from human acute lymphoblastic leukemia Jurkat cells were analyzed. Only 2,500 cells suspended in PBS were directly dropped onto a stainless MALDI sample plate, followed by mixing with matrix on the sample plate. Up to 150 metabolite peaks were detected from a single analysis within 90 s. For multivariate analysis of Jurkat cells against drug-treatment, three anticancer drugs were utilized. Principal component analysis of metabolites showed clear independent clusters for cells treated with these anticancer drugs. Furthermore, several metabolites involved in nucleotide synthesis were found to contribute to the separation of each cluster. These data suggest that the high-throughput MALDI-MS-based metabolomic technique proposed in the present study can be utilized for drug screening and validation of drug efficacy and safety.