Prognostic and immunological roles of ammonia-induced cell death-related genes in non-small cell lung cancer.

BACKGROUND: Lung cancer remains the predominant cause of cancer-related mortality globally, with non-small cell lung cancer (NSCLC) comprising approximately 85% of cases, despite advancements in immunotherapy. This challenge is primarily due to the persistent dysfunction of effector T cells within the tumor microenvironment (TME). Ammonia-induced cell death (AICD), a newly identified form of programmed cell death, leads to the attrition of CD8⁺ T cells and contributes to immune suppression. However, the clinical significance of AICD in NSCLC has yet to be elucidated. In light of this context, the current study seeks to investigate AICD-related genes and their prognostic and immunological implications in NSCLC. METHODS: Transcriptomic data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts were integrated with single-cell RNA sequencing and functional assays. Glutamine metabolism–related genes were retrieved from GeneCards and intersected with NSCLC differentially expressed genes to identify candidate AICD regulators. Prognostic value was evaluated by Kaplan–Meier survival and ROC analyses. Single-cell and immune infiltration analyses were used to define gene expression across malignant and immune subsets. Finally, Jurkat T cells were exposed to ammonia stress to validate gene function in AICD. RESULTS: Four genes—SLC7A5, SLC2A1, CAV1, and SPP1—emerged as key regulators of AICD in NSCLC. These genes were aberrantly expressed in tumors, stratified patient survival, and correlated with immune checkpoint activity and TME immunosuppression. A gene signature derived from the four regulators effectively predicted overall survival and immune response. Single-cell analysis confirmed their distribution across malignant and immune subpopulations. Functional assays demonstrated that CAV1, SPP1, and SLC7A5 protected against ammonia-induced T cell death, whereas SLC2A1 increased susceptibility. CONCLUSION: This study establishes AICD as a clinically relevant metabolic cell death mechanism in NSCLC and identifies SLC7A5, SLC2A1, CAV1, and SPP1 as potential prognostic biomarkers and therapeutic targets. Targeting ammonia metabolism may offer new strategies to overcome immune resistance and enhance immunotherapy efficacy in NSCLC.