BPGM as an intrinsic brake to constrain metastasis through phospho-epigenetic-mediated carnitine biosynthesis suppression

Metabolic adaptations that fuel metastatic dissemination are increasingly mapped, yet the existence of intrinsic metabolic "brakes" that actively restrain metastatic progression remains enigmatic. Here, we unveil bisphosphoglycerate mutase (BPGM) as a previously unrecognized metastasis suppressor that orchestrates a phospho-epigenetic relay linking glycolytic flux to carnitine-dependent fatty acid oxidation. Through high-resolution metabolomics, we discover that BPGM and its catalytic product 2,3-bisphosphoglycerate (2,3-BPG) constitute a metabolic checkpoint whose disruption predicts metastatic virulence in multiple cancers. Mechanistically, BPGM suppresses metastasis by triggering CDK1-T₁₄ phosphorylation-dependent assembly of an EZH2-H3K27me3 repressor complex that silences γ-butyrobetaine hydroxylase (BBOX1), the rate-limiting enzyme in carnitine biosynthesis. This phospho-switch mechanism converts glycolytic 2,3-BPG levels into epigenetic orchestrator, thereby starving metastatic cells of carnitine-required fatty acid oxidation. Hypoxia-mediated KDM4A-H3K9me3 cascade emerges as the upstream inactivator of this metabolic-epigenetic checkpoint, explaining how tumor microenvironmental stress liberates metastatic potential. Therapeutically, pharmacological BBOX1 inhibition with Meldonium recapitulates BPGM-mediated metastasis suppression in orthotopic models, reducing metastatic burden. These findings reveal BPGM as a metabolic gatekeeper that integrates bioenergetic sensing with chromatin remodeling to constrain metastatic competence, while hypoxia-mediated checkpoint failure unleashes carnitine-fueled metastatic progression. Targeting the hypoxia-BPGM-BBOX1 axis represents an innovative approach for metastasis-preventive therapy.