Microbiota-driven antitumour immunity mediated by dendritic cell migration

https://www.nature.com/articles/s41586-025-09249-8

It has been known for a decade or so that the gut microbiome influences the success of cancer immunotherapy: if the right bacteria are present (e.g., Ruminococcus spp. and Prevotellaceae spp.), they can boost the immune system and support checkpoint inhibitors, drugs that block proteins called checkpoints. Checkpoints are exploited by cancer cells to evade immune destruction, so blocking them lets the immune system do its job, further supported by molecules or receptors produced by some bacteria.

In this article, a team from the National Cancer Center in Tokyo analyzed faecal samples from non-small cell lung cancer and gastric cancer patients who had been treated with checkpoint inhibitors: they found one particular bacterial strain enriched in “responders”, i.e., patients who did show improvement from treatment. Finding this one strain, of Hominenteromicrobium mulieris, is a colossal endeavor with no guarantee of success, so it is fantastic to see it work -apparently even better than other bacteria that were previously found to support checkpoint inhibitors. They further found, after transplanting the bacteria to mice, that it works by stimulating dendritic cells in the gut, which can migrate to the tumor to activate tumor-specific T cells. Now we have to wait for human trials.

In other words, that is one example where the inflammatory (or immune-stimulatory) potential of gut bacteria has a positive impact. I will come back to this topic soon.