An integrated analysis reveals DEFB1, SPINK6 and tumor-suppressive Anaerococcus as prognostic determinants in oral squamous cell carcinoma

Abstract

Background

Oral squamous cell carcinoma (OSCC) is a highly aggressive malignant tumor for which reliable prognostic biomarkers are currently lacking. Growing evidence suggests that the tumor-associated microbiota plays an important role in cancer progression and patient prognosis. However, the prognostic significance of intratumoral microbes in OSCC and their interactions with host genes remain poorly understood.

Methods

This study integrated microbiome and transcriptome data from The Cancer Genome Atlas (TCGA) and employed Cox and LASSO regression to identify survival-associated microbes (SAMs). Microbial–immune interactions were explored through clustering and immune infiltration analyses. Key prognosis-associated microbial genes (PAMGs) were further screened by combining differential gene expression analysis, protein–protein interaction (PPI) network construction, and survival analysis. Functional enrichment analysis was subsequently performed. Experimental validation was conducted using a co-culture system of WSU-HN30 cells and Anaerococcus supernatant.

Results

A total of 63 SAMs were identified, among which Anaerococcus and Peptoniphilus exhibited a significant synergistic relationship. DEFB1 (low expression) and SPINK6 (high expression) were identified as key PAMGs. ROC analysis yielded AUC values of 0.89, 0.85, and 0.82 at 1, 3, and 5 years, respectively, indicating good prognostic predictive ability. Functional analyses indicated that these genes are primarily involved in the cell cycle, epithelial–mesenchymal transition (EMT), and E2F/G2M signaling pathways. In in vitro experiments, Anaerococcus was found to inhibit the proliferation, migration, and invasion of WSU-HN30 cells, accompanied by the upregulation of DEFB1 and down-regulation of SPINK6.

Conclusion

This study uncovers novel microbe–gene interactions in OSCC and identifies DEFB1 and SPINK6 as potential prognostic biomarkers. The results suggest that Anaerococcus may exert a protective role by regulating host gene expression, providing new insights for prognostic stratification and potential therapeutic interventions in OSCC.