Abstract
Iron sustains cancer cell plasticity, yet it also sensitizes the mesenchymal, drug-tolerant phenotype to ferroptosis. This posits that iron compartmentalization must be tightly regulated. However, the molecular machinery governing organelle Fe(II) compartmentalization remains elusive. Here, we show that BDH2 is a key effector of inter-organelle Fe(II) redistribution and ferroptosis vulnerability during melanoma transition from a melanocytic (MEL) to a mesenchymal-like (MES) phenotype. In MEL cells, BDH2 localizes at the mitochondria-lysosome contacts (MLCs) to generate the siderophore 2,5-dihydroxybenzoic acid (2,5-DHBA), which ferries iron into the mitochondria. Fe(II) transfer by BDH2 supports mitochondrial bioenergetics, which is required to maintain lysosomal acidification and MLC formation. Loss of BDH2 alters lysosomal pH and MLC tethering dynamics, causing lysosomal iron sequestration, which primes MES cells for ferroptosis. Rescuing BDH2 expression, or supplementing 2,5-DHBA, rectifies lysosomal pH and MLCs, protecting MES cells from ferroptosis and enhancing their ability to metastasize. Thus, we unveil a BDH2-dependent mechanism that orchestrates inter-organelle Fe(II) transfer, linking metabolic regulation of lysosomal pH to the ferroptosis vulnerability of the mesenchymal, drug-tolerant cancer cells.