CXCL12 regulates breast cancer metastasis and T lymphocyte infiltration

Purpose: Breast cancer (BC) is a malignant tumor with the highest incidence rate in women. This work explored the function of CXCL12 in tumor metastasis. Methods: CXCL12 protein expression levels were assessedby IHC in breast cancer tissues. String revealed thatCXCL12 interacts with CXCL10 protein molecules. The GEPIA2 database revealed that CXCL12 was negatively correlated with CXCL10.CXCL12. The effects of CXCL12 on invasion and migration were detected by scratch and transwell experiments in breast cancer cells. CD4+ T and CD8+ T cells in the inflammatory microenvironment of breast cancer patients were evaluated with the NGDC database and verified by IHC. Results: CXCL12 knockdown inhibited migration and invasion and enhanced the expression and secretion of CXCL10 in BC. CXCL10 isresponsible for the recruitment of CD4+ and CD8+ T lymphocytes into tumors and enhances antitumoreffects. The single-cell data showed that the patients in the CXCL10+CD4+/CD8+ T-cell group and the CXCL12-CD4+/CD8+ T-cell group had better prognoses. Conclusions: CXCL12 promoted BC migration and invasion. On the otherhand, CXCL12 inhibited the expression and secretion of CXCL10, further inhibiting T lymphocyteinfiltration and promoting breast cancer metastasis in the TME.