SLC2A3 promotes head and neck squamous cancer developing through negatively regulating CD8⁺ T cell in tumor...

Recent studies have identified SLC2A3 as being abnormally upregulated in multiple tumor types, correlating with poor survival and disrupted microenvironments. However, its prognostic significance in head and neck squamous cell carcinoma (HNSC) remains underexplored. In this study, SLC2A3 was screened as a potential risk gene influencing both immune and tumor components within the tumor microenvironment (TME) of 504 HNSC patients from the TCGA database. Immune infiltration analyses and clinical significance on SLC2A3 were conducted using ESTIMATE, CIBERSORT, ssGSEA, TIMER and clinical prognosis parameters. Additionally, the single-cell dataset is used to analyze the expression of SLC2A3 in various subpopulations. The magnetic activated cell sorting (MACS) is used to isolate CD8⁺ T cells from PBMCs or tumor tissues. Flow cytometry is used to identify purified and activated CD8⁺ T cells. GSEA and WB were used to investigate the molecular mechanism of SLC2A3 in CD8⁺ T cells. The co-culture system of CD8⁺ T cells and TU686 was used to investigate the effects of SLC2A3 on immune cells and tumor development. In this study, SLC2A3 was identified as a potential risk gene affecting both immune cells and tumor components within the TME of 504 HNSC patients derived from the TCGA database. We conducted immune infiltration analyses and assessed the clinical significance of SLC2A3 using various bioinformatics tools, including ESTIMATE, CIBERSORT, ssGSEA, and TIMER, along with clinical prognosis parameters. The single-cell RNA sequencing dataset was utilized to examine SLC2A3 expression across different cellular subpopulations. Magnetic activated cell sorting (MACS) was employed to isolate CD8⁺ T cells from peripheral blood mononuclear cells (PBMCs) or tumor tissues. Flow cytometry was implemented to confirm the purity and activation state of the isolated CD8⁺ T cells. GSEA and Western blot were applied to explore the molecular mechanisms underlying SLC2A3's role in CD8⁺ T cells. Lastly, a co-culture system involving CD8⁺ T cells and TU686 tumor cells was established to study the impact of SLC2A3 on immune cell function and tumor progression. SLC2A3 emerges as an actively variable gene within the immune and stromal components of the TME, linked to aggravated immune infiltration and poor clinical outcomes. The upregulated expression of SLC2A3 is predominantly enriched in immune-related biological processes and linked to the suppression of CD8⁺ T cells, which are crucial for the survival of HNSC patients. Furthermore, SLC2A3 exhibits specific overexpression in CD8⁺ T cells and may potentially trigger ferroptosis. Knockdown of SLC2A3 led to a significant increase in the proliferation of CD8⁺ T cells compared to those without knockdown. In co-culture systems, CD8⁺ T cells with SLC2A3 knockdown demonstrated an enhanced ability to eliminate tumor cells compared to those without the knockdown. SLC2A3 is associated with changes in the TME and prognostic indicators. Moreover, high SLC2A3 expression in CD8⁺ T cells may drive cell death through ferroptosis, fostering tumor progression.