Abstract 5426: Vesicle-mediated mitochondrial clearance presents an actionable metabolic vulnerability in triple-negative breast cancer

Selective autophagy of mitochondria is known to promote survival and progression of cancer cells in various malignancies including triple-negative breast cancer (TNBC). Here, we aimed to identify the essential metabolic adaptations that support mitochondrial quality control with the goal to uncover actionable metabolic vulnerabilities with therapeutic potential. Using an integrated approach of proteomics and untargeted and stable-isotope resolved metabolomics, coupled with functional experimental analyses, we define an alternative mechanism to mitophagy enabled by an onco-metabolic program of heightened extracellular sphingomyelin salvaging in TNBC that facilitates extracellular vesicle (EV)-mediated intracellular clearance of mitochondrial damage. Targeting of the cancer cell sphingolipid onco-metabolic pathway via repurposing of eliglustat, a selective small molecule inhibitor of glucosylceramide synthase (UGCG), resulted in ceramide-mediated compensatory mitophagy and subsequent cancer cell death in vitro and attenuated tumor growth and prolonged overall survival at clinically achievable doses in an orthotopic syngeneic mouse models of TNBC as well as in human xenograft models. Our study defines a mechanism of aberrant sphingolipid metabolism that underlies an actionable metabolic vulnerability for anti-cancer treatment. Citation Format: Mingxin Zuo. Vesicle-mediated mitochondrial clearance presents an actionable metabolic vulnerability in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5426.