P4HA1 facilitates SPP1+ tumor-associated macrophages by activating the hypoxia pathway in head and neck squamous cell carcinoma

Tumor-associated macrophages (TAMs) with highly expressed secreted phosphoprotein 1 (SPP1) carry immunosuppressive property as a potential target for tumor metastasis. However, the mechanisms regulating SPP1 + TAMs in head and neck squamous cell carcinoma (HNSCC) remain poorly understood. This study employs a combination of single-cell and bulk RNA sequencing bioinformatics analysis to confirm the impact of TAMs with high levels of SPP1 on patient prognosis. Additionally, Key genes linked to SPP1 + macrophages were identified using weighted gene co-expression network analysis. A prognostic model was built using the Random Forest algorithm. Here we show, P4HA1 is strongly correlated with SPP1 + macrophages and holds significant value in predicting patient prognosis and diagnosis. In vitro experiments demonstrated that TAMs educated by HNSCC cells with knockdown P4HA1 expressed lower SPP1 level compared to the control group. Furthermore, Gene Set Variation Analysis and Gene Set Enrichment Analysis indicated that P4HA1 mediates the hypoxia pathway in HNSCC. In xenografts model, P4HA1 knockdown effectively suppressed tumor malignant progress, confirming that P4HA1 was positive correlation with SPP1 + TAMs and could mediate tumor hypoxia pathways. Overall, this study identified P4HA1 as a key gene involved in regulating SPP1 + TAMs through modulating hypoxia, providing a potential macrophage-centered therapeutic target in HNSCC.