Cancer stem cells (CSCs) are the leading cause of cancer initiation, metastasis and chemoresistance, thus eliminating them could lead to permanent cancer eradication. CSCs have a unique genotipic phenotype and exhibit metabolic plasticity based on the tumor
microenvironment.
we compared the metabolic fingerprints of H460 cancer cell culture cells grown as adherent (2D) or as three-dimensional (3D) tumor spheroids in a spheroid medium and low- serum medium. Tumor spheroids are an optimal in vitro model to enrich the CSCs subpopulations and to mimic the trascrittomic shift and the 3D inter-cellular transport of nutrients and oxygen.
Multivariate analysis showed a significant shift from the 2D typical oxidative metabolism to a glycolytic and gluconeogenesis metabolism in 3D conditions. Indeed, 3D cultures showed changes of glycolytic intermediates (D-Glucose-6P, D-Fructose-6P, Dihydroxiacetone phosphate) as well as intracellular accumulation of lactic acid.
In 3D the intracellular concentration of AAs was strongly reduced compared to 2D, thus suggesting either higher utilization or reduced production; the latter, could be associated with the lower proliferation rate of H460 cells in 3D cultures. Strikingly, 2D cultures showed use aspartate to generate asparagine that support mTOR, this is not observed in 3D. Overall, this study indicates that lung CSCs use glycolysis/gluconeogenesis and AAs metabolism to satisfy their energy demands and these could certainly play a key role in the acquisition of stemness-like properties. Further experiments, i.e. transcriptional analysis will be performed to validate our preliminary results. Metabolomics approaches are powerful tools for the direct profiling of cell metabolism and to uncover mechanisms of transcriptional activation of metabolic pathway in CSCs.
