Gut bacteria have a profound impact on health by aiding digestion, providing nutrients and metabolites, and working with the immune system to fend off pathogens. Some gut bacteria, however, have been implicated in progression of cancers of the gut and associated organs.
A new study by researchers from the University of Chicago shows that some commensal bacteria promote the development of leukemia caused by the murine leukemia virus (MuLV) by suppressing the animal’s adaptive anti-tumor immune response. When both the virus and commensal bacteria are present in mice, three genes known as negative immune regulators are expressed more, or upregulated, which in turn tamps down the immune response that would otherwise kill the tumor cells. Two of these three negative immune regulators are also known to be indicators of poor prognosis for humans with some forms of cancer.
“These two negative immune regulators have been really well documented to be poor prognostic factors in some human cancers, but nobody knew why,” said Tatyana Golovkina, PhD, Professor of Microbiology at UChicago and senior author of the study. “Using a mouse model of leukemia, we found that the bacteria contribute to upregulation of these negative immune regulators, allowing developing tumors to escape recognition by the immune system.”
Results of the research, “Gut commensal bacteria enhance pathogenesis of a tumorigenic murine retrovirus,” were published September 13 in Cell Reports.
Read the full story "Some viruses that cause cancer suppress the immune system with help from common bacteria" published on September 13, 2022.