A rise in double-strand breaks sensitizes tumours to oxidative metabolism inhibitors

ABSTRACTDouble strand brakes (DSB) accumulate in cellular DNA as a result of deficiencies in homologous recombination repair systems, such as mutations in BRCA genes, or upon antitumoral treatments. In the present study we show that the accumulation of DSB, regardless of its origins, leads to a shift towards oxidative metabolism. We have identified that DSB-induced reactive oxygen species (ROS) promote the activation of NRF2 which downregulates the glycolytic transcription factor HIF-1. HIF-1 inhibition is a key step in this metabolic shift, because leads to the reduction of PDHK1 levels and the consequential activation of pyruvate dehydrogenase, a mitochondrial gatekeeper of cellular metabolism, promoting this metabolic shift. Remarkably, after the induction of DSBs, the tumour is more sensitive to the inhibition of oxidative metabolism since both treatments synergize in vivo, resulting in reduced tumour growth. Therefore, we demonstrate a significant feedback between DSBs induction and cancer cell metabolism that ultimately limits the cells potential for metabolic plasticity, hence sensitizing it to the action of counteracting drugs.