Spatial transcriptomics and single-cell analysis reveal GSTO2-mediated protective networks in oral squamous cell carcinoma tumor microenvironment – Research

Background:

Oral squamous cell carcinoma (OSCC) exhibits significant cellular heterogeneity and metabolic reprogramming that influence tumor progression and therapeutic responses. However, the molecular mechanisms underlying these processes remain poorly understood.

Methods:

We performed an integrated analysis of single-cell RNA sequencing and spatial transcriptomics analysis on OSCC samples to characterize cellular heterogeneity and identify key regulatory factors. Summary-data-based Mendelian randomization (SMR) analysis was conducted to establish causal links between gene expression and OSCC risk. Functional enrichment, protein-protein interaction (PPI) network analysis, molecular docking, and co-immunoprecipitation (Co-IP) were employed to elucidate molecular mechanisms.

Results:

Single-cell analysis of 50,667 cells identified nine distinct cell populations with epithelial cells showing the highest glutamine metabolism activity. SMR analysis revealed glutathione S-transferase omega 2 (GSTO2) as a genetically validated protective factor for OSCC risk. GSTO2-positive epithelial cells exhibited enhanced metabolic reprogramming, particularly in fatty acid degradation and amino acid catabolism pathways. Spatial transcriptomics demonstrated that GSTO2-positive cells were spatially organized and showed enhanced communication with immune cells. Protein-protein interaction analysis identified interferon-stimulated genes (MX1, OAS1, UBE2L6) and immunoproteasome subunits (PSMB8, PSMB9) as core regulatory hubs. Molecular docking confirmed direct binding interactions between GSTO2 and these hub proteins, with MX1-GSTO2 showing the strongest binding affinity (-10.7 kcal/mol). Co-immunoprecipitation experiments validated the physical interaction between GSTO2 and MX1.

Conclusions:

This study indicates that GSTO2 defines an epithelial subset characterized by enhanced metabolic activity and immune interactions, highlighting its potential as a biomarker and therapeutic target in OSCC.