CD45+ single cell transcriptomes in the MC38 tumor microenvironment

Colorectal cancer (CRC) continues to increase globally, thus identification of mechanisms that prevent cancer are sorely needed. The microbiota has emerged as a key driver of CRC pathogenesis; however, little is known regarding how specific microbes might prevent CRC. Using transplantation of the microbiota from individuals with or without CRC into germfree mice, we identified that the microbiota harbored by non-diseased individuals can reduce tumor formation and Bacteroides uniformis was a potentially protective member of the microbiota. Single cell sequencing of CD45+ immune cells within the MC38 tumor shows a change in T and NK cell populations with B. uniformis treatment. T cell deficient mice were still protected from CRC in response to B. uniformis treatment, while NK cell depletion eradicated microbe-mediated protection. B. uniformis is reduced in individuals with CRC and thus our data identify B. uniformis as a microbe enriched in healthy individuals that can reduce tumor formation through enhanced NK cell activity. Overall design: Sorted CD45+ cells from the MC38 tumor microenvironment from mice with or without B. uniformis oral gavage supplementation. Cells from 10 male or 10 female mice were pooled for each sample.