31P-Magnetic resonance spectra of ovarian cancer cells exposed to chemotherapy within a three-dimensional Matrigel construct

We aimed to determine the metabolic profile and effects of chemotherapy on ovarian cancer cell metabolism in a three-dimensional (3D) vs. a two-dimensional (2D) construct using 31P-magnetic resonance spectroscopy (MRS). Three ovarian cancer cell lines were embedded in a 3D perfused Matrigel construct or grown in a 2D monolayer. Metabolic differences between the three cell lines were determined using 31P-MRS both in the 3D and in the 2D constructs. Cells were incubated with three different cytotoxic drugs at LC50 for 44 h and evaluated for metabolic changes using 31P-MRS. While the 3D construct allowed MRS assessment of viable cells, the 2D monolayer permitted evaluation of non-viable cell extracts. In both cells embedded in Matrigel (CEM) and cells grown in monolayers (CGM) different cancer cell lines showed characteristic metabolic fingerprints, which differed significantly between CEM and CGM. In contrast to the cell monolayer, CEM allowed continuous monitoring of the changes in 31P-MRS spectra over time following exposure to chemotherapy, demonstrating a progressive decrease in specific phosphorylated metabolites. The metabolic response of CEM and CGM to various antimitotic agents was significantly different. We conclude that different ovarian cancer cell lines show characteristic 31P-MRS fingerprints and specific metabolic changes in response to cytotoxic drug treatment. The perfused 3D Matrigel construct is superior to the 2D tissue monolayer for 31P-MRS studies, because it simulates the in vivo conditions more closely and facilitates MRS evaluation of viable cells as well as continuous monitoring of metabolic changes in response to chemotherapy over time.