Figure 1.

Proposed mechanism of action of gut microbiota-mediated 3-IAA chemosensitization

Indole-3-acetic acid (3-IAA) is a metabolite of tryptophan broken down by gut microbiota, and higher serum 3-IAA levels were found in pancreatic cancer patients who responded to chemotherapy. The gut microbiome of responders was enhanced in 3-IAA producers (including Bacteroides). Through multiple loss-of- and gain-of-function pre-clinical experiments, the authors demonstrate neutrophil-mediated accumulation of reactive oxygen species, which led to improved response to chemotherapy.