The Effects Of Staphylococcus Aureus And Bacterial Flagellin On The Characteristics Of Breast Cancer Cells

Staphylococcus aureus(S.aureus)and Salmonella are common food-borne bacteria and are also a member of the human microbiota.It showed that in breast cancer patients,their abundance is higher than that in healthy populations.During the growth of bacteria in the body,the virulence factors and metabolites produced will disrupt the physiological balance and cause the activation of the relevant immune response.In addition,bacterial infection and invasion of cells can interfere with and destroy cell functions,affecting cell growth and even lead to cell death.In this study,after treating breast cancer cells with S.aureus,it was observed that the proliferation rate and migration ability of the cells were inhibited,and the cells were more prone to apoptosis.However,how does S.aureus affect host cells after invasion remains largely unknown.Here,we found that S.aureus can invade non-phagocytic cells and affect the growth of host cells.In addition,through transcriptome sequencing,it was found that S.aureus invasion significantly up-regulated the expression of 14 genes including IFIT family genes,CCL5,OASL,IFI44,and ISG15 in MCF-7,Sum159 and MCF-10A cell lines.Moreover,in two different molecular types breast cancer cells MCF-7 and Sum159,S.aureus invasion significantly down-regulated the expression of10 genes including SEMA5B,IGFBP5,SLC7A11 and MAP7D2.These genes play different roles in the occurrence,development and immune response of multiple cancer types.In addition,by stimulating breast cancer cells with Salmonella virulence factor-flagellin,it was found that flagellin can activate the TLR5-NF-κB signaling pathway and regulate the production of pro-inflammatory cytokines,and thereby inhibiting breast cancer cell proliferation,migration and clonal formation.This study provides new clues for elucidating the impact of conditional pathogens such as S.aureus on breast cancer cells,and provides new ideas for solving postoperative infections caused by S.aureus,etc.We also provide more support for targeting TLR5 as a treatment for breast cancer.