The NF-κB/LY6E axis promotes oral squamous cell carcinoma stemness by responding to interaction with macrophages

Cancer stemness plays a pivotal role in driving metastasis and recurrence in oral squamous cell carcinoma (OSCC). Although immune-tumor cell interactions regulate cancer stemness plasticity, the underlying mechanisms remain incompletely characterized. This study aimed to explore the key signaling axis mediating tumor-immune cell crosstalk that governs cancer stemness in OSCC. Single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database revealed eight major cell clusters and five epithelial sub-clusters within OSCC. CytoTRACE analysis revealed that epithelial sub-cluster 1 exhibiting the highest stemness potential, from which ten stemness-related genes were derived. Among these, LY6E was screened as an enhancer-controlled gene in OSCC cells. LY6E knockdown significantly suppressed self-renewal and proliferation of OSCC cells in vitro, as well as tumor growth in vivo. Mechanistically, NF-κB bound to the enhancer of LY6E to drive its transcription. Cell-cell communication analysis highlighted that macrophages are the dominant immune cells interacting with malignant cells. Macrophage-derived TNFα facilitated NF-κB enrichment at the LY6E enhancer regions and upregulated its transcription in OSCC cells. TNFα stimulation, exposure to macrophage-conditioned medium, or coculture with macrophages significantly promoted the self-renewal and proliferation of OSCC cells, but these effects were abolished by LY6E knockdown or NF-κB inhibition. In conclusion, the NF-κB/LY6E axis is a key signaling hub in response to macrophage-OSCC cell interaction in promoting cancer stemness.