Spatially restricted iron-metabolism-associated stress programs prime invasive mesenchymal glioblastoma states in human tissue-context models.

Abstract

Background: Glioblastoma (GBM) recurrence is driven by invasive tumor cells that infiltrate surrounding brain tissue and evade surgical and therapeutic eradication. While dysregulated iron handling is a well-recognized feature of malignant cancers, its contribution to invasive GBM cell states in the physiological context of human cortical tissue remains poorly defined.

Methods: We performed multiregional single-nucleus RNA sequencing of human GBM specimens encompassing tumor core, tumor periphery, and infiltrated cortex to map iron-associated transcriptional programs validated by spatial transcriptomics. Correlative analyses were combined with functional validation using patient-derived GBM cell lines and human organotypic cortical slice cultures exposed to noncytotoxic iron supplementation to model iron-rich tumor microenvironments.

Results: Malignant cells from the tumor core exhibited coordinated upregulation of iron uptake and storage pathways alongside invasion-associated gene programs. At single-cell resolution, iron metabolism and invasion signatures were correlated, defining a core-enriched malignant subpopulation with mesenchymal-like transcriptional identity, stress-adaptive features, and angiogenic signaling that aggregate in specific spatial niches. Functionally, iron exposure altered migration in a cell-state-dependent manner and increased tumor growth and invasion in human cortical slice cultures. Increased VIM, MMP9, and HIF1A expression was consistent with activation of mesenchymal-like and stress-response programs, although mechanistic dependence was not tested.

Conclusion: Iron-handling and invasion-associated programs co-occur in a core-enriched mesenchymal-like GBM state. In patient-derived cell and human cortical slice models, noncytotoxic particulate and soluble iron altered migration in a cell-state-dependent manner and increased tissue invasion. These findings support iron availability as a component of the microenvironment associated with invasive GBM phenotypes, while its necessity and underlying mechanism remain to be established.