Resumen
To identify inhibitors of mitochondrial respiration as potential anticancer drugs is not an easy matter since cancer cells cultured as monolayers may escape by shifting their metabolic preference toward the use of glycolysis. Here we propose to capitalize on this apparent weakness to exploit the associated increase in L-lactate release as a primary screening assay to identify and optimize the development of inhibitors of mitochondrial oxidative phosphorylation. As a secondary assay, we used a protocol based on O2 consumption rate in permeabilized cancer cells to get further insights on a possible direct or indirect inhibition of mitochondrial electron transport chain. Finally, 3D tumor spheroids helped us to further select drug candidates endowed with the capacity to exert growth inhibitory effects in tumor-mimicking conditions but also to act as potent radiosensitizers by promoting reoxygenation.