Alter between gut bacteria and blood metabolites and the anti-tumor effects of Faecalibacterium prausnitzii in breast cancer.

Abstract

e12575 Background: The aim was to evaluate the changes of 16S rDNA sequencing and LC-MS metabolomics in breast cancer and explore the growth inhibition of breast cancer cells by Faecalibacterium prausnitzii. Methods: We performed the 16S rDNA sequencing of gut bacteria and the LC-MS metabolomics analysis of blood samples in 25 breast cancer patients and 25 benign breast disease controls. Correlation analysis of significant flora and metabolites were processed, including correlation coefficient calculation, matrix heat map analysis, cluster analysis, correlation network analysis, and scatter plot analysis. We screened for intestinal flora that may participate in breast cancer development and try to test and verify. CCK-8, apoptosis and transwell assays were explored to detect the growth inhibition of breast cancer cells by Faecalibacterium prausnitzii. Western blot was used to analyze the changes of IL-6/STAT3 pathway by Faecalibacterium prausnitzii. Results: Total 49 significantly different flora and 26 different metabolites were screened between two groups, and the correlation was calculated. Relative abudance of Firmicutes and Bacteroidetes were decreased, while relative abundance of verrucomicrobla, proteobacteria and actinobacteria was increased in breast cancer group. Differentially expressed metabolites were mainly enriched in pathways such as linoleic acid metabolism, retrograde endocannabinoid signaling, biosynthesis of unsaturated fatty acids, choline metabolism in cancer and arachidonic acid metabolism. Lipid upregulation was found in breast cancer patients, especially phosphorocholine. The abundance of Faecalibacterium was reduced in breast cancer patients, which was negatively correlated with various phosphorylcholines. Moreover, Faecalibacterium prausnitzii, the most well-known species in Faecalibacterium genus, could inhibit the secretion of IL-6 and the phosphorylation of JAK2/STAT3 in breast cancer cells. Faecalibacterium prausnitzii also suppressed the proliferation and invasion and promoted the apoptosis of breast cancer cells, while these effects disappeared after adding recombinant human IL-6. Conclusions: Flora-metabolites combined with the flora-bacteria (such as Faecalibacterium combined with phosphorocholine) might a new detection method for breast cancer. Faecalibacterium may be helpful for prevention of breast cancer. Faecalibacterium prausnitzii suppresses the growth of breast cancer cells through inhibition of IL-6/STAT3 pathway.