Tracer‐Based Metabolic NMR‐Based Flux Analysis in a Leukaemia Cell Line

High levels of reactive oxygen species (ROS) have a profound impact on acute myeloid leukaemia cells and can be used to specifically target these cells with novel therapies. We have previously shown how the combination of two redeployed drugs, the contraceptive steroid medroxyprogesterone and the lipid‐regulating drug bezafibrate exert anti‐leukaemic effects by producing ROS. Here we report a (13)C‐tracer‐based NMR metabolic study to understand how these drugs work in K562 leukaemia cells. Our study shows that [1,2‐(13)C]glucose is incorporated into ribose sugars, indicating activity in oxidative and non‐oxidative pentose phosphate pathways alongside lactate production. There is little label incorporation into the tricarboxylic acid cycle from glucose, but much greater incorporation arises from the use of [3‐(13)C]glutamine. The combined medroxyprogesterone and bezafibrate treatment decreases label incorporation from both glucose and glutamine into α‐ketoglutarate and increased that for succinate, which is consistent with ROS‐mediated conversion of α‐ketoglutarate to succinate. Most interestingly, this combined treatment drastically reduced the production of several pyrimidine synthesis intermediates.