Co-Housed Mice Reveal the Tumor-Promoting Potential of Akkermansia muciniphila

Specific pathogen-free laboratory mice are widely used in biomedical research; however, their neonatal-like physiological state often limits their ability to model adult human conditions. Here, we induced adult-like physiological characteristics in laboratory mice by co-housing them with naturally raised mice obtained from pet stores. Co-housing resulted in significant changes in the gut microbiota composition and a marked suppression of tumor growth in multiple tissues. We discovered reduction in Akkermansia muciniphila was a contributing factor to the observed tumor suppression. Furthermore, decreased serum indole metabolite levels were linked to both Akkermansia muciniphila and the tumor-suppressive effects. These findings suggest that Akkermansia muciniphila may, under certain situations, be tumor-promoting and highlight the value of using adult-like mouse models in uncovering critical environmental factors in cancer and other health conditions.