Single-cell analysis reveals an endothelial TP53-CXCL14 axis in breast cancer progression

The TME of BRCA plays a core role in disease progression and treatment resistance. As a pleiotropic chemokine, CXCL14 exhibits context-dependent roles in cancer. While its potential prognostic value in BRCA has been noted, its precise role and regulatory mechanisms remain elusive.

The expression of CXCL14, its prognostic significance, and its association with the immune microenvironment were systematically analyzed using public databases, such as TCGA, GEO, and cBioPortal. In vitro experiments were performed to generate HUVEC cells with stable TP53 silencing or overexpression. ChIP-qPCR and dual-luciferase reporter assays were used to assess TP53's effect on CXCL14 transcriptional regulation. In vivo tumor growth was evaluated in a xenograft mouse model co-injected with HUVECs and MDA-231 cells.

High expression of CXCL14 was significantly associated with rounding down for 4 and rounding up for 5 indicators, such as favorable OS (HR = 0.64, P = 0.006), and PFS (HR = 0.65, P = 0.002) in BRCA patients, and indicated a better response to immune checkpoint inhibitor treatment. Its expression is associated with a remodeled immune microenvironment, characterized by an increase in the infiltration of anti-tumor immune cells (e.g., CD8⁺T cells) and a decrease in immunosuppressive cells (e.g., M2 macrophages). ScRNA-seq analysis identified ECs as the main cellular source of CXCL14 in the TME for the first time. Mechanistic analyses indicated that mutant TP53 binds the CXCL14 promoter, supporting transcriptional repression. Functional experiments confirmed that the secretion of CXCL14 by TP53-mutated ECs decreased, thereby promoting the migration and invasion of BRCA cells. In vivo, co-injection of TP53-mutant (R175H) HUVECs with BRCA cells resulted in significantly larger and heavier tumors, accompanied by increased Ki-67 staining and decreased CXCL14 expression, compared to the wild-type TP53 group.

Our findings indicate that CXCL14 serves as a promising independent prognostic factor associated with an anti-tumor immune microenvironment in BRCA, with ECs identified as a major source. Furthermore, TP53 mutations may promote BRCA progression by repressing endothelial through CXCL14 transcription.