Endogenous murine microbiota member Faecalibaculum rodentium and its human homolog protect from intestinal tumor growth

The microbiota has been shown to promote intestinal tumorigenesis, but a possible anti-tumorigenic effect has also been postulated. Here, we demonstrate that changes in microbiota and mucus composition are concomitant with tumorigenesis. We identified two anti-tumorigenic strains of the microbiota, Faecalibaculum rodentium and its human homolog Holdemanella biformis, which are strongly underrepresented during tumorigenesis. Reconstitution of Apc(Min/+) or AOM/DSS-treated mice with an isolate of F. rodentium (F. PB1) or its metabolic products reduced tumor growth. F. PB1 and H. biformis produced short-chain fatty acids (SCFAs) that contributed to control protein acetylation and tumor cell proliferation by inhibiting calcineurin/NFATc3 activation both in mouse and human settings. Thus, we have identified endogenous anti-tumorigenic bacterial strains with strong diagnostic, therapeutic and translational potential.