Rôle des génotoxines produites par des bactéries du microbiote dans le cancer colorectal

Numerous studies support a role for the intestinal microbiota in colorectal tumorigenesis. Recent results have suggested that bacteria of the microbiota could be associated with the presence of tumours. Some can be directly genotoxic : as we showed, strains of Escherichia coli, an ubiquitous member of the colon flora, synthesize a genotoxin called colibactin. These bacteria induce DNA double strand breaks in intestinal cells and trigger chromosomal instability, gene mutations and cell transformation. Moreover it was recently shown that colibactin-producing E. coli promote colorectal cancer in a murine IL10-/- model. Thus long-term colonization of the colon with rogue commensal bacteria capable of causing chronic DNA-damage could contribute to sporadic colorectal cancer development.