Ferroptosis-resistant myeloid niche shapes tumor natural evolution in glioblastoma.

Glioblastoma (GBM) exhibits marked spatial and cellular heterogeneity, driving aggressive progression and therapy resistance. Utilizing multifocal GBM as a unique model of tumor evolution, we integrated multi-omics including scRNA-seq, scATAC-seq, and spatial transcriptomics (ST). This revealed a subcluster of bone marrow-derived macrophages (BMDMs), NUPR1+ myeloid-derived suppressor cells (MDSCs), enriched in peri-necrotic niches and higher-evolution lesions. Supported by multiplex immunofluorescence (mIF) and ultrastructural analyses, these MDSCs spatially co-localized and actively engaged in functional crosstalk with mesenchymal-like (MES) tumor cells. NUPR1+ MDSCs upregulated hypoxia and ferroptosis-resistance pathways and expressed a core Spatial-MDSC-Ferroptosis (SMF) program that independently predicted poor survival, irrespective of hypoxia, and correlated with a reduced response to neoadjuvant anti-PD-1 therapy. Epigenetic profiling revealed CEBPA as a core transcriptional regulator orchestrating the SMF program. In vitro, ferroptosis induction in macrophages promoted migration and mesenchymal transition of co-cultured GBM cells, phenotypes that were effectively reversed by ferrostatin-1 (Fer-1) and pazopanib. These findings reveal a spatially defined, ferroptosis-resistant myeloid niche driving MES tumor progression, providing mechanistic insights into myeloid-tumor interactions and identifying the myeloid compartment as a potential therapeutic target in GBM.