Multi-omics identification and experimental validation of a histidine metabolism-related prognostic signature in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the most common and lethal malignant tumors, and its high heterogeneity poses significant challenges for prognosis assessment. While metabolic reprogramming is a tumor hallmark, the specific role of histidine metabolism remains underexplored. First, we conducted a comprehensive analysis of histidine metabolism-related genes (HMRGs) in LUAD transcriptome data. We constructed histidine metabolism-related molecular subtypes and subsequently established an interpretable prognostic model based on SHAP. Potential drugs for LUAD were predicted using the DSiGDB database. Single-cell sequencing analysis and virtual knockout were performed to explore the core gene’s role in the tumor microenvironment and transcriptional regulation. Finally, we validated the clinical protein expression of the core gene using tissue microarrays (TMAs) and verified its downstream mechanisms and drug sensitivity through in vitro functional assays. The constructed subtypes of histidine metabolism-related molecules can effectively distinguish LUAD patients with different immune states and prognostic patterns. Our constructed risk model demonstrated robust prognostic predictive power across cohorts, identifying GCLM as the most critical core gene. Immunohistochemistry of the TMA confirmed significant GCLM overexpression in clinical LUAD tissues. Functionally, GCLM knockdown significantly inhibited LUAD cell proliferation, migration, and invasion. Concordant with the scRNA-seq virtual knockout predictions, Western blotting revealed that GCLM knockdown robustly upregulated core tight junction proteins. Furthermore, computational drug screening and molecular docking identified Rifampicin as a candidate targeting GCLM; in vitro assays confirmed its anti-proliferative effect against LUAD cells, which was markedly altered upon GCLM knockdown. This study first reveals the pivotal role of HMRGs in LUAD, proposes histidine metabolism-related subtypes and prognostic models with potential clinical utility, and identifies GCLM as a key therapeutic target, laying the foundation for future metabolic-targeted therapies.