Metabolic profiling by 13C-NMR spectroscopy: [1,2-13C2]glucose reveals a heterogeneous metabolism in human leukemia T cells

Metabolomics by proton nuclear magnetic resonance spectroscopy of the response to chloroethylnitrosourea reveals drug efficacy and tumor adaptive metabolic pathways

Metabolomics of tumors may allow discovery of tumor biomarkers and metabolic therapeutic targets. Metabolomics by two-dimensional proton high-resolution magic angle spinning nuclear magnetic resonance spectroscopy was applied to investigate metabolite disorders following treatment by chloroethylnitrosourea of murine B16 melanoma (n = 33) and 3LL pulmonary carcinoma (n = 31) in vivo. Treated tumors of both types resumed growth after a delay. Nitrosoureas provoke DNA damage but the metabolic consequences of genotoxic stress are little known yet. Although some differences were observed in the metabolite profile of untreated tumor types, the prominent metabolic features of the response to nitrosourea were common to both. During the growth inhibition phase, there was an accumulation of glucose (more than x10; P < 0.05), glutamine (x3 to 4; P < 0.01), and aspartate (x2 to 5; P < 0.01). This response testified to nucleoside de novo synthesis down-regulation and drug efficacy. However, this phase also involved the increase in alanine (P < 0.001 in B16 melanoma), the decrease in succinate (P < 0.001), and the accumulation of serine-derived metabolites (glycine, phosphoethanolamine, and formate; P < 0.01). This response witnessed the activation of pathways implicated in energy production and resumption of nucleotide de novo synthesis, thus metabolic pathways of DNA repair and adaptation to treatment. During the growth recovery phase, it remained polyunsaturated fatty acid accumulation (x1.5 to 2; P < 0.05) and reduced utilization of glucose compared with glutamine (P < 0.05), a metabolic fingerprint of adaptation. Thus, this study provides the proof of principle that metabolomics of tumor response to an anticancer agent may help discover metabolic pathways of drug efficacy and adaptation to treatment.

NMR-based metabolic profiling of human hepatoma cells in relation to cell growth by culture media analysis

Metabolic profiling is a metabolomic approach that allows the characterization of metabolic phenotypes under specific set of conditions. In the present paper we investigated the metabolism of sparse and high density cultures in relation to different cell growth phases. Changes in the metabolome were evaluated by using 1H-NMR spectroscopy, correlation map and Multivariate Data Analysis on the net balances of metabolites in the medium. This approach allowed us to identify two different metabolic profiles in relation to the cell growth phases in subconfluence and confluence cultures. The results have been interpreted on the basis of patterns of correlations obtained in the two physiological cell states. Cells almost arrested in G0/G1 phase by contact dependent growth inhibition underwent changes in the channeling of amino acids utilization from synthetic to energetic purpose and in anaplerosis/cataplerosis regulation of the TCA cycle.

Altered glucose metabolism in childhood pre-B acute lymphoblastic leukaemia

The cells of solid tumours are known to have an altered metabolism, with high rates of glucose uptake and glycolysis, which results in the excessive production of lactate. To date there has been no definitive research documenting metabolic changes in acute lymphoblastic leukaemia (ALL) cells. In order to investigate whether ALL cells have an altered metabolism, we initially compared the transcriptional profiles of 22 specimens from paediatric patients diagnosed with ALL to five CD34+ specimens isolated from bone marrow, which was verified in an independent cohort of 101 specimens. Profiling revealed the upregulation of genes facilitating glycolysis in the ALL specimens compared to the CD34+ specimens, while those involved in the tricarboxylic acid cycle were downregulated. Functional studies supported the microarray findings threefold: (1) higher expression of the glucose transport protein glucose transporter 1 in ALL compared to CD34+ specimens, (2) the excessive production of lactate in ALL cell lines and (3) sensitivity of ALL cell lines to the glycolysis inhibitor 2-deoxy-D-glucose. While metabolic alterations have been well documented in solid tumours, this is the first study to provide direct evidence for the existence of metabolic changes in the leukaemic cells of ALL patients. The finding offers new options for targeted therapy for ALL patients.