Gut microbiota from colorectal cancer patients enhances the progression of intestinal adenoma in Apc mice.

Background: Accumulating evidence points to a close relationship between gut dysbiosis and colorectal cancer (CRC). As >90% of CRC develop from adenoma, we aimed to investigate the crucial role of imbalanced gut microbiota on the progression of intestinal adenoma.

Methods: The Apc mice gavage with phosphate-buffered saline (PBS), feces from healthy controls or CRC patients after antibiotic cocktails. The intestinal tissues were isolated for histopathology, western blotting, and RNA-seq. The microbiota of feces and short-chain fatty acids (SCFAs) were analysed by 16S rDNA Amplicon Sequencing and gas chromatography.

Findings: The Apcmice gavaged by feces from CRC patients had more intestinal tumours compared with those fed with feces from healthy controls or PBS. Administration of feces from CRC patients increased tumour proliferation and decreased apoptosis in tumour cells, accompanied by impairment of gut barrier function and up-regulation the pro-inflammatory cytokines profile. The up-regulated the expression of β-catenin and cyclinD1 further indicating the activation of Wnt signalling pathway. The abundance of pathogenic bacteria was increased after FMT, while producing SCFAs bacteria and SCFAs production were decreased.

Interpretation: Gut microbiota of CRC patients disrupted intestinal barrier, induced low-grade inflammation and dysbiosis. The altered gut microbiota enhanced the progression of intestinal adenomas in Apcmice, suggesting that a new strategy to target gut microbiota against CRC could be noted. FUND: The study was supported by the National Natural Science Foundation of China, Tianjin Research Programme of Application Foundation and Advanced Technology of China, and China Postdoctoral Science Foundation.