A compelling new proof of concept study from researchers at Northwestern University has demonstrated how certain types of protective gut bacteria can help negate the damaging side effects of toxic chemotherapy drugs on other beneficial bacteria. The research raises the prospect of future probiotics designed to enhance gut health in cancer patients.
One of the more fascinating recent findings in microbiome research has been the growing understanding into how the efficacy of certain drugs are influenced by gut bacteria. Studies have found some types of gut bacteria can amplify the beneficial effects of cancer treatment, while other types can dramatically increase the toxicity of chemotherapy.
This new research was inspired by a process called bioremediation where microbes are recruited to clean up environmental pollutants. Erica Hartmann, senior author on the new study, says previous research had identified specific bacteria that can degrade toxins from cancer drugs.
“We wondered if, by breaking down drugs, these bacteria could protect the microbes around them,” says Hartmann. “Our study shows the answer is ‘yes.’ If some bacteria can break down toxins fast enough, that provides a protective effect for the microbial community.”
In laboratory conditions, the researchers created a simulated gut microbiome that included several bacterial strains known to break down a chemotherapy drug called doxorubicin, alongside other strains known to be sensitive to the toxic effects of the drug. Upon exposing this “mock gut community” to doxorubicin the researchers found the protective bacteria helped degrade the drug, preserving the populations of bacteria most sensitive to the drug’s effects.
This means it could be possible to ameliorate some of the more toxic side effects of chemotherapy by making sure some of these protective bacterial strains are present before treatment. This could help preserve diversity in the gut microbiome, something Hartmann notes is particularly important in pediatric patients.
“Microbes in your gut help digest your food and keep you healthy,” says Hartmann. “Killing these microbes is especially harmful for children because there’s some evidence that disruption in the gut microbiome early in life can lead to potential health conditions later in life.”
The researchers do point out we are still some way off turning these preliminary discoveries into clinical treatments. One unanswered question raised by this study, for example, is whether the protective metabolites produced by these bacterial strains reduce the general efficacy of the chemotherapy drug.
Early hypotheses suggest intravenously administered doxorubicin exerts its anti-tumor effects rapidly before ultimately accumulating in the gut, so this kind of probiotic adjunct shouldn’t hinder the chemotherapy. But further work will be needed to explore these issues before a clinical treatment appears.
“There are several eventual applications that would be great to help cancer patients – particularly pediatric patients – not experience such harsh side effects,” adds Hartmann. “But we’re still far from actually making that a reality.”
The new study was published in the journal mSphere.
Source: Northwestern University