Mechanisms of synergistic regulation of the tumor microenvironment by fibroblasts and keratinocytes in esophageal squamous cell carcinoma.

backgroundEsophageal squamous cell carcinoma (ESCC) is a highly invasive malignant tumor, and its tumor microenvironment (TME) plays a pivotal role in disease progression and treatment resistance. As key components of the TME, fibroblasts and keratinocytes are hypothesized to synergistically regulate tumor biological behavior.

methodsThis study integrated single-cell transcriptomic data with bulk RNA-seq data from ESCC to investigate the interaction mechanisms between fibroblasts and keratinocytes within the tumor microenvironment. Rigorous quality control, standardization, and clustering analyses were performed on the single-cell data, identifying ten distinct cell subpopulations, including fibroblasts and keratinocytes. The proportions and expression profile differences of these two cell types were compared between experimental and control groups. Cell-cell communication analysis deciphered ligand-receptor pairs and associated signaling pathways governing intercellular interactions. Molecular subtyping of The Cancer Genome Atlas (TCGA) cohort samples was subsequently performed using non-negative matrix factorization (NMF) based on interaction-specific genes. A multi-gene prognostic model was constructed via least absolute shrinkage and selection operator (LASSO) regression, and its predictive efficacy was evaluated. Finally, functional enrichment, immune microenvironment assessment, and differential expression analyses revealed differences in biological functions and immune infiltration patterns across distinct risk subtypes.

resultsBy integrating the gene expression profiles of these two cell types, a novel molecular classification system was successfully established, enabling the stratification of ESCC patients into C1(high-risk) and C2(low-risk) subtypes with marked differences in survival outcomes. Patients classified as subtype C2 had a median survival of 3.8 months, significantly longer than the 1.8 months observed in the high-risk subtype C1, highlighting the substantial clinical relevance of this classification. Further analysis revealed that the high-risk cohort exhibited significant enrichment in metabolism-related pathways, such as endocytosis and glyceride metabolism, whereas the low-risk cohort was predominantly associated with pathways involved in cell junctions and structural maintenance. Mechanistically, the interaction between these two cell types jointly promotes the reprogramming of the tumor immune microenvironment by regulating immune cell infiltration, HLA molecule expression, and immune checkpoint activity. Furthermore, the study identified key genes, including SLIT2 and SFRP1, which display cell-type-specific expression patterns in ESCC and hold potential as prognostic biomarkers or therapeutic targets. This research provides novel insights into the regulatory mechanisms of the ESCC tumor microenvironment, laying a theoretical foundation for the development of precision therapeutic strategies targeting the tumor microenvironment.

conclusionThis study elucidates the synergistic regulatory mechanisms between fibroblasts and keratinocytes within the tumor microenvironment of ESCC. These findings offer a novel theoretical foundation for molecular classification, prognosis prediction, and precision treatment of ESCC.