Metal ion transporter SLC39A14-mediated ferroptosis and glycosylation modulate the tumor immune microenvironment

Background: Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has emerged as a pivotal mechanism in cancer progression and therapeutic resistance. Concurrently, glycosylation, as a key post-translational modification, plays a critical role in regulating cell signaling, immune evasion, and metastasis. Although both processes are independently implicated in tumor biology, the intersection between ferroptosis and glycosylation remains largely unexplored. Methods: We performed a comprehensive pan-cancer multi-omics analysis, integrating bulk transcriptomics, epigenomics, and single-cell RNA sequencing datasets. Ferroptosis and glycosylation-related genes were curated from The Molecular Signatures Database (MSigDB), leading to the identification of the metal ion transporter, SLC39A14 (solute carrier family 39 member 14), as a key intersecting gene. A ferroptosis-related gene signature was constructed using machine learning and Cox regression models, followed by survival analyses, immune microenvironment profiling, and a pathway enrichment analysis across The Cancer Genome Atlas (TCGA) cohort. Results: SLC39A14 was found to be significantly upregulated across multiple tumor types and associated with a poor prognosis, immune-stromal infiltration, and ferroptosis resistance. Among all cancer types analyzed, glioblastoma multiforme (GBM) and kidney renal cell carcinoma (KIRC) exhibited the significantly prognostic associations and the most pronounced differential expression of SLC39A14. Single-cell analysis revealed that SLC39A14 expression was enriched between stromal and immune populations, hypoxic perivascular niches, confirming its microenvironment-specific functions. These findings were corroborated by DNA methylation data showing promoter hypomethylation of SLC39A14 in tumors compared to normal tissues. Functionally, SLC39A14 was highly enriched in pathways related to angiogenesis, the epithelial-to-mesenchymal transition, cytokine signaling, and oxidative stress adaptation including vascular endothelial growth factor (VEGF) and cell metabolism-related signaling. A nomogram integrating SLC39A14 expression with clinical parameters improved overall survival predictions. Conclusions: In this study, we identified SLC39A14 as a dual regulator at the interface of ferroptosis and glycosylation, with significant impacts on tumor microenvironmental remodeling and therapeutic resistance. By leveraging multi-omics and single-cell transcriptomic data, we establish SLC39A14 as a promising prognostic biomarker and therapeutic target, particularly in brain and kidney cancers where ferroptosis modulation could offer novel clinical strategies.