How Some E. coli Strains Promote Colon Cancer Revealed in New Study

Recent research has revealed how certain strains of Escherichia coli (E. coli) in the gut contribute to colon cancer development. The study, published in Nature by teams from VIB-UGent and VIB-VUB, identifies a crucial mechanism that could lead to new approaches in cancer prevention.

The research focuses on pks+ E. coli, which produces colibactin, a DNA-damaging toxin. These bacteria are found in higher numbers in colon cancer patients. The study shows that these E. coli can switch between free-swimming and attaching to the gut lining using specific pili with adhesins that bind to intestinal cell receptors.

"We found that this pilus binding significantly increases the number, size, and aggressiveness of colon tumors," explains Maude Jans, the study's first author.

The researchers identified two key adhesins, FimH and FmlH, that enable bacterial attachment. By interfering with these attachment mechanisms, they were able to significantly reduce tumor development in preclinical models.

Importantly, the team developed a therapeutic approach using molecules that block these bacterial adhesins. This method successfully suppressed DNA damage and tumor growth without affecting beneficial gut bacteria, unlike antibiotics.

The study also raises concerns about some E. coli strains used as probiotics. While these strains carry pks genes, they typically have a variant of FimH that binds poorly. However, the researchers demonstrated that just a few mutations could restore strong binding and genotoxic activity in these strains.

This research not only enhances our understanding of how certain gut bacteria contribute to colon cancer but also opens up new possibilities for prevention strategies targeting bacterial attachment mechanisms.