Your Gut’s Role in Cancer Immunotherapy Response
WISDom Pdx
A cartoon image of multicolored microorganisms in the shape of a stomach against a white background
Ample research in gastrointestinal health highlights the influence of the gut microbiome on wellness, with a healthier gut having more diverse microbial species present. A variety of yogurts, kombuchas, and probiotic supplements often mention this in their advertisements. While the microbiome is already a popular scientific topic today, it’s becoming increasingly relevant in the mammoth field of cancer research – particularly, the gut microbiome’s influence on immune checkpoint therapy (ICT). ICT is designed to kill tumors by preventing the binding of proteins that “turn off” a cell’s immune response to foreign bodies like cancer cells, allowing T cells to continue recognizing and destroying unwelcome invaders. Recently, researchers from the University of Texas Southwestern Medical Center published their compelling findings on the subject in Science Immunology.
How can the bacteria harbored in the gut microbiome positively impact cancer treatment? The answer: by promoting antitumor responses in secondary lymphoid organs such as the spleen or bowel. ICT activates these bacteria to disperse from the gut to extraintestinal sites and optimize antitumor T cell response, a response often weakened in aggressive cancers. In their study, mice were selectively treated with a number of antibiotics for a week before being grafted with melanoma tumors and put on ICT, with tumor volume being tracked up to harvest. The relative bacterial abundance within each mouse’s microbiome was then quantified.
Astoundingly, the mice treated with antibiotics showed markedly worse responses to ICT, with treated mice showing lower levels of effector T cells than control mice. Researchers postulate their diminished microbial diversity from antibiotic treatment limited the flow of gut bacteria to secondary lymphoid organs, which dampened the mice’s extraintestinal antitumor response. These findings indicate the role of the gut microbiota pushes ICT to its most effective state and does so through orchestrated extraintestinal responses. Now is as good a time as any to take care of your gut flora – they’re working overtime.
Author Bio
Jane Arterberry is working on her undergraduate degree in biology with a chemistry minor at Portland State University Honors College. She is a member of PSU’s eXtreme Virus Lab, a BUILD EXITO trainee, Knight Cancer Institute intern, and is interested in immunology, genetics, and molecular biology. Her favorite things include watching live music, petting everyone’s dogs, and making academia a more inclusive place.
