How gut bacteria affect responses to cancer immunotherapy. « Medicine in the Library

Cancer immunotherapy has transformed the treatment of many types of cancer. However, for reasons that are still poorly understood, not all patients derive the same benefits from these powerful therapies.

And new study explored why some patients fail to respond to cancer immunotherapy, showing that specific gut bacteria can alter therapeutic responses and immune signaling in mouse models. The research is published in “Nature“.

According to this new research from the Harvard Medical School and Dana-Farber Cancer Institute, the composition of patients’ gut microbiome may be a significant factor in response to immunotherapy.
The results suggest that gut bacteria may influence the activity of two immune molecules, programmed cell death ligand 2 (PD-L2) and repulsive guide molecule b (RGMb).

Using antibodies to block the activity of both molecules, or the interaction between them, improved the response to cancer immunotherapy.
The findings may inform the design of treatments that increase the efficacy of cancer immunotherapy among suboptimal responding patients.

“There are likely many other ways the microbiome can influence cancer immunity in general and cancer immunotherapy in particular“said Prof. Kasper. “With this work, we have found a completely new way of looking at how the gut microbiota affects not only the efficacy of cancer treatments, but also cancer immunity in general.“.

Read abstract of the article:
Targeting PD-L2–RGMb overcomes microbiome-related immunotherapy resistance.
Park, J.S., Gazzaniga, F.S., Wu, M. ……….Dennis L. Kasper & Arlene H. Sharpe
Nature (2023).

Source: Harvard Medical School