SPP1-SRD5A3 signaling axis regulated lymph node metastasis by activating Mucin type O glycan biosynthesis

Lymph node metastasis (LNM) holds substantial implications for the recurrence and survival of cancer patients, but the intricate regulatory mechanisms underlying LNM remain poorly understood. MTOGB was dominantly increased in LNM of pan-cancer, significantly activated in epithelial cells and enriched in LNM. Subsequently, we identified a specific epithelial cell subpopulation, EC4, located at the terminal of the LNM differentiation trajectory Lineage2. By intersecting differentially expressed genes in cluster 2, EC4 and Lineage2, we identified six crucial genes. Notably, the expression of Steroid 5α-reductase 3 (SRD5A3) increased with the progression of LNM stages. Knockdown of SRD5A3 effectively suppressed the MTOGB, blocking metastasis in both cell and animal models. Nilotinib was screened as a candidate inhibitor of SRD5A3 and was confirmed to remarkably decrease cancer cell metastasis. SOX4 was identified as a potential transcription factor of SRD5A3, modulated by a dramatic increase in cell communication of SPP1⁺ macrophages in the immune microenvironment. The supernatant from SPP1⁺ macrophage significantly enhanced the expression of SOX4/SRD5A3 and the metastatic ability of cancer cells, and this effect was reversed by the deletion of SPP1. Collectively, our findings illuminate the SPP1-SRD5A3 signaling as the crucial driver in LNM and suggest that its blockade could be a promising option for overcoming LNM.