Formation of an Immunosuppressive Spatial Network Between Tumor-Associated SPP1⁺ Macrophages and Fibroblasts in Cervical Cancer with Distant Metastasis

Background Cervical cancer (CC) is a common malignancy among women worldwide, and distant metastasis is the main cause of treatment failure and mortality. Immune cells, stromal cells, and their interactive networks within the tumor microenvironment (TME) play a key role in the development, colonization, and immune escape in metastasis. For example, tumor-associated macrophages (TAMs) are often polarized to the M2 phenotype, thereby promoting angiogenesis and creating an immunosuppressive microenvironment; cancer-associated fibroblasts enhance the invasiveness of tumor cells through matrix remodeling; at the same time, the exhaustion of immune cell function further weakens the anti-tumor immune response and promotes tumor immune escape. Methods In this study, tumor tissues and peripheral blood mononuclear cell (PBMC) samples were collected from three cervical cancer patients with distant metastasis and three patients without metastasis at the First Affiliated Hospital of Shandong Second Medical University in 2024, yielding a total of 11 specimens. Subsequently, single-cell RNA sequencing (scRNA-seq) technology was used for detection. Cell clustering and Uniform Manifold Approximation and Projection (UMAP) visualization were implemented by Seurat software. Cell type annotation was performed by SingleR. Differential gene identification was completed by the function of FindMarkers. Furthermore, clusterProfiler was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis; CellPhoneDB was used to predict intercellular ligand-receptor interactions; and Monocle was used to perform pseudotime trajectory analysis. Results In metastatic cervical cancer tissue, the proportion of myofibroblast-like cancer-associated fibroblasts (myCAFs) is significantly increased, with high expression of genes such as COL4A1, FN1, and SPP1. MyCAFs closely interact with SPP1⁺ macrophages through the collagen and FN1-mediated signaling pathways, thereby activating pro-metastatic pathways such as NF-κB and TNF, and suppressing CD8⁺ T cell function. In peripheral blood, the proportion of inflammatory monocytes and non-classical monocytes increased, and they highly expressed pro-metastatic genes such as CX3CR1 and STAT1; in contrast, the number of NK cells and T cells decreased and their function was impaired. Further pseudotieme trajectory analysis revealed that during the metastasis process, the expression of key genes in CAFs, macrophages and peripheral blood mononuclear cells (such as COL4A1, MMP9, CX3CR1) changed dynamically, suggesting that they play an important role in driving cellular functional remodeling and abnormal immune microenvironment. Conclusion This study systematically delineated the immune landscapes of tumor tissue and peripheral blood in metastatic cervical cancer, revealing that the myCAFs–SPP1⁺ macrophage axis and peripheral immune remodeling play central roles in metastasis. Dynamic changes in key genes and functional impairment of immune cells collectively drive tumor progression. These findings provide new insights into the mechanisms of cervical cancer metastasis and offer potential ideas for the development of precision treatment strategies targeting the tumor microenvironment.