Gut microbiota and metabolic control of immune checkpoint blockade in cancer.

Abstract

The human gastrointestinal tract is colonized by trillions of microbes, collectively termed the gut microbiota, which dynamically shape states of health and disease. This occurs through the modulation of host immunity and through metabolites produced by these microbes, which act both locally and at distal organs. Seminal research has defined that the gut microbiota are essential for successful cancer immunotherapy, with specific microbes and associated metabolites linked to therapeutic outcomes. The mechanisms accounting for this remain preliminary, with additional research implicating diet in shaping the composition and functional potential of the gut microbiota to steer host immunity toward fighting or supporting malignant tumors. The goal of this review is to summarize recent advances in a key communication loop between diet, the gut microbiota, and host immunity as it relates to immune checkpoint blockade in cancer. Further, we discuss gaps in knowledge and future opportunities to harness this knowledge to improve therapeutic strategies.