Listeria monocytogenes promotes breast cancer proliferation and enhances the survival rate of circulating breast cancer cells

Mammary gland microbiota is closely related to the progression of breast cancer (BC). Recent studies have shown that Listeria is differentially enriched in breast cancer and normal paracancerous breast tissue, and associated with epithelial-mesenchymal transition (EMT) in breast cancer. However, studies have rarely reported the relationship between Listeria monocytogenes ( L. monocytogenes ) enrichment and clinical parameters and possible mechanisms in breast cancer. In this study, we found that L. monocytogenes was highly enriched in the cytoplasm of cells, especially in tumor tissues. By analyzing the relationship between L. monocytogenes enrichment and the clinicopathological indicators and prognostic survival of patients, we found that L. monocytogenes is positively correlated with BC proliferation, metastasis, and poor recurrence-free survival (RFS) on patients. Moreover, we performed cell proliferation and invasion assays on breast cancer cells bearing L. monocytogenes , and proved that L. monocytogenes was able to promote the proliferation and invasion of breast cancer cells, their proliferation and invasion capacity was significantly reduced after antibiotic treatment. Mechanistically, L. monocytogenes was identified to increase the survival rate of circulating breast cancer cells by implementing the fluid shear stress model. In conclusion, our study demonstrated that L. monocytogenes could promote breast cancer development by increasing survival rate of circulating cancer cells.