Vesicle-mediated mitochondrial clearance presents an actionable metabolic vulnerability in triple-negative breast cancer.

Abstract

Selective autophagy of mitochondria is known to promote cancer cell survival and progression, including in triple-negative breast cancer (TNBC). Here, we apply an integrated multi-omics approach together with functional experimental analyses to investigate metabolic adaptations that support mitochondrial quality control in TNBC. We detail a mitochondrial quality control mechanism, complementary to mitophagy, that is enabled by a program of heightened extracellular sphingomyelin salvaging in TNBC coupled with extracellular vesicle-mediated intracellular clearance of mitochondrial damage. Targeting of this onco-metabolic pathway via repurposing of eliglustat, a selective small molecule inhibitor of glucosylceramide synthase, results in ceramide-mediated compensatory mitophagy and cancer cell death in vitro and attenuates tumor growth and prolongs overall survival at clinically achievable doses in orthotopic syngeneic mouse models of TNBC as well as in human cell line-derived xenograft models. Our study defines an unexplored mechanism of aberrant sphingolipid metabolism that underlies an actionable metabolic vulnerability for anti-cancer treatment.