Profiling metabolic and bioenergetic properties of 3D tumor microtissues (LB171)

Abstract

Cellular metabolism and bioenergetics processes are increasingly recognized as critical regulators in the pathogenesis of cancers. Metabolic activity and bioenergetic processes are often characterized using typical 2 dimensional (2D) adherent cell culture systems; however, this approach lacks the 3 dimensional (3D) context and heterogeneity of tumor tissue in vivo, which may have significant effects on metabolic and bioenergetic behavior. A novel and more physiologically relevant model is the use of microtissues (also known as spheroids). Metabolic activity and bioenergetic function were accessed in individual cancer cell line microtissues using a newly designed 96‐well plate for the Seahorse Bioscience XFe96 Extracellular Flux Analyzer. Mitochondrial and glycolytic functions were determined simultaneously using the Cell Mito Stress and Glycolytic Stress Tests, respectively. Several parameters, including: seeding density, microtissue size, and substrate identity and availability were investigated. Further, the potential of the microtissues to switch bioenergetic pathways was determined by stimulating maximal respiration (OCR) and maximal extracellular acidification rate (ECAR). Comparisons of microtissues to typical 2D adherent cell cultures were also performed. Initial comparative data are consistent with a shift from the highly proliferative nature of 2D cultures to a physiological 3D model where growth and metabolic properties of the cell are balanced. Technical aspects of this assay system and implications of this work for future studies in cancer biology will be discussed.