Berberine may rescue Fusobacterium nucleatum-induced colorectal tumorigenesis by modulating the tumor...

Accumulating evidence links colorectal cancer (CRC) with the intestinal microbiota. However, the disturbance of intestinal microbiota and the role of Fusobacterium nucleatum during the colorectal adenoma-carcinoma sequence have not yet been evaluated.

454 FLX pyrosequencing was used to evaluate the disturbance of intestinal microbiota during the adenoma-carcinoma sequence pathway of CRC. Intestinal microbiota and mucosa tumor-immune cytokines were detected in mice after introducing 1,2-dimethylhydrazine (DMH), F. nucleatum or Berberine (BBR), using pyrosequencing and Bio-Plex Pro™ cytokine assays, respectively. Protein expressions were detected by western blotting.

The levels of opportunistic pathogens, such as Fusobacterium, Streptococcus and Enterococcus spp. gradually increased during the colorectal adenoma-carcinoma sequence in human fecal and mucosal samples. F. nucleatum treatment significantly altered lumen microbial structures, with increased Tenericutes and Verrucomicrobia (opportunistic pathogens) (P < 0.05 = in wild-type C57BL/6 and mice with DMH treatment). BBR intervention reversed the F. nucleatum-mediated increase in opportunistic pathogens, and the secretion of IL-21/22/31, CD40L and the expression of p-STAT3, p-STAT5 and p-ERK1/2 in mice, compared with mice fed with F. nucleatum alone.

F. nucleatum colonization in the intestine may prompt colorectal tumorigenesis. BBR could rescue F. nucleatum-induced colorectal tumorigenesis by modulating the tumor microenvironment and blocking the activation of tumorigenesis-related pathways.