Despite the progress in use of hyperthermia in clinical practice, the thermosensitivity of cancer cells is poorly
understood. In a previous study, we found that sensitivity to hyperthermia varied among ovarian cancer cell lines.
Upon hyperthermia, glycolytic enzymes decreased in hyperthermia-resistant SKOV3 cells. However, the mechanisms
of glycolysis inhibition and their relationship with thermoresistance remain to be explored. In this study, metabolomic
analysis indicated downregulation of glycolytic metabolites in SKOV3 cells after hyperthermia. Proteomic and
pathway analyses predicted that the ubiquitin pathway was specifically activated in resistant SKOV3 cells, compared
with hyperthermia-sensitive A2780 cells, and STUB1, a ubiquitin ligase, potentially targeted PKM, a glycolytic
rate-limiting enzyme. PKM was found to be degraded via ubiquitination upon hyperthermia. Although glycolysis was
inactivated by hyperthermia, ATP production was maintained. We observed that oxygen consumption and
mitochondrial membrane potential were activated in SKOV3 cells but suppressed in A2780 cells. The activation of
mitochondria could compensate for the ATP production lost due to suppression of glycolysis by hyperthermia.
Although the physiological significance has not yet been elucidated, our results demonstrated that metabolomic
adaptation from the Warburg effect to mitochondrial oxidative phosphorylation could contribute to thermoresistance in
ovarian cancer cells.
Keywords:Hyperthermia, Ovarian cancer, Metabolic shift, Heat stress, Pathway Analysis
Publication Date: 2021-10-25