Administration of Parabacteroides distasonis in the Attenuation of Colorectal Cancer in a Carcinogenic Murine Model

Abstract

The gut microbiome and its effects on its host’s health has become an important factor when trying to understand that etiology of disease and therefore its diagnosis and treatment. In previous studies, the bacterial species Parabacteroides distasonis was found to have an inverse correlation between its gut microbiome abundance and CRC susceptibility (Barrington et al. 2018). In this study we report that oral administration of Parabacteroides distasonis does not provide any significant effect in the attenuation of colorectal cancer, in measures of tumor count (p=0.5821), average tumor size (p=0.4496), as well as tumor load (p=0.9304) when comparing a control gavage to a treatment gavage of P. distasonis in an AOM-induced colorectal cancer model using FVB/NJ mice fed a ketogenic diet. These results suggest that the ketogenic diet may be inhibiting the bacteria from properly colonizing the gut of the FVB mice and therefore preventing P. distasonis from attenuating CRC risk. Our next step would then be to use a droplet digital PCR assay to quantify absolute abundance values for the bacterial populations and confirm the population dynamics of P. distasonis in the gut of the mice. Ultimately, we hope to find the genetic mechanisms responsible for the regulation of the bacteria to further understand how inter-individual genetic differences effect the differential responses to dietary patterns, therefore advancing precision dietetics as a component of precision medicine.