Fluorometric Methods for Detection of Mitochondrial Membrane Depolarization Induced by CD95 Activation

Mitochondria are key organelles implicated in energy supply and apoptosis. Therefore, tracking mitochondria and measuring their membrane potential is of crucial interest to monitor the CD95-mediated apoptotic signal. In this chapter, we report how we evaluate the drop of the mitochondrial transmembrane potential in leukemic cells and adherent triple negative breast cancer cells exposed to cytotoxic CD95L. We describe a simple, robust, and well-established protocol using classical fluorescent probes, DIOC₆(3) and TMRM. Living cells are loaded with these cationic dyes, which accumulate in mitochondria. After CD95 activation, organelle depolarization is assessed using flow cytometry.