If It Works, Don’t Touch It? A Cell-Based Approach to Studying 2-[18F]FDG Metabolism

Author(s)
Eva-Maria Klebermass, Mahshid Mahmudi, Barbara Katharina Geist, Verena Pichler, Chrysoula Vraka, Theresa Balber, Anne Miller, Arvand Haschemi, Helmut Viernstein, Nataliya Rohr-Udilova, Marcus Hacker, Markus Mitterhauser
Abstract

The glucose derivative 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) is still the most used radiotracer for positron emission tomography, as it visualizes glucose utilization and energy demand. In general, 2-[18F]FDG is said to be trapped intracellularly as 2-[18F]FDG-6-phosphate, which cannot be further metabolized. However, increasingly, this dogma is being questioned because of publications showing metabolism beyond 2-[18F]FDG-6-phosphate and even postulating 2-[18F]FDG imaging to depend on the enzyme hexose-6-phosphate dehydrogenase in the endoplasmic reticulum. Therefore, we aimed to study 2-[18F]FDG metabolism in the human cancer cell lines HT1080, HT29 and Huh7 applying HPLC. We then compared 2-[18F]FDG metabolism with intracellular tracer accumulation, efflux and the cells’ metabolic state and used a graphical Gaussian model to visualize metabolic patterns. The extent of 2-[18F]FDG metabolism varied considerably, dependent on the cell line, and was significantly enhanced by glucose withdrawal. However, the metabolic pattern was quite conserved. The most important radiometabolites beyond 2-[18F]FDG-6-phosphate were 2-[18F]FDMannose-6-phosphate, 2-[18F]FDG-1,6-bisphosphate and 2-[18F]FD-phosphogluconolactone. Enhanced radiometabolite formation under glucose reduction was accompanied by reduced efflux and mirrored the cells’ metabolic switch as assessed via extracellular lactate levels. We conclude that there can be considerable metabolism beyond 2-[18F]FDG-6-phosphate in cancer cell lines and a comprehensive understanding of 2-[18F]FDG metabolism might help to improve cancer research and tumor diagnosis.

Organisation(s)
Department of Pharmaceutical Sciences
External organisation(s)
Medizinische Universität Wien, Ludwig Boltzmann Intitute Applied Diagnostics
Journal
Pharmaceuticals
Volume
14
No. of pages
15
DOI
https://doi.org/10.3390/ph14090910
Publication date
09-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
104020 Radiochemistry
Keywords
ASJC Scopus subject areas
Drug Discovery, Molecular Medicine, Pharmaceutical Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/e55a613d-37d3-4753-a423-3a164203c84d