Naturally occurring gut bacteria can clean up chemo toxins in the body, study finds
In the human gut, good bacteria make great neighbors.
new Northwestern University study found that specific types of gut
bacteria can protect other good bacteria from cancer treatments —
mitigating harmful, drug-induced changes to the gut microbiome. By
metabolizing chemotherapy drugs, the protective bacteria could temper
short- and long-term side effects of treatment.
microbial communities include various types of bacteria typically found
in the human gut. Credit: Northwestern University
the research could potentially lead to new dietary supplements,
probiotics or engineered therapeutics to help boost cancer patients’ gut
health. Because chemotherapy-related microbiome changes in children are
linked to health complications later in life — including obesity,
asthma and diabetes — discovering new strategies for protecting the gut
is particularly important for pediatric cancer patients.
“We were really inspired by bioremediation, which uses microbes to clean up polluted environments,” said Northwestern’s Erica Hartmann,
the study’s senior author. “Usually bioremediation applies to
groundwater or soil, but, here, we have applied it to the gut. We know
that certain bacteria can breakdown toxic cancer treatments. We wondered
if, by breaking down drugs, these bacteria could protect the microbes
around them. Our study shows the answer is ‘yes.’ If some bacteria can
break down toxins fast enough, that provides a protective effect for the
The research was published in the journal mSphere.
Hartmann is an assistant professor of environmental biology at Northwestern’s McCormick School of Engineering.
Ryan Blaustein, a former postdoctoral fellow in Hartmann’s laboratory,
is the paper’s first author. He is now a postdoctoral fellow at the
National Institutes of Health.
cancer treatments are life-saving, they also cause profoundly harsh and
painful side effects, including gastrointestinal issues.
Chemotherapies, in particular, can obliterate the healthy, “good”
bacteria in the human gut.
drugs do not differentiate between killing cancer cells and killing
microbes,” Hartmann said. “Microbes in your gut help digest your food
and keep you healthy. 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
with Dr. Patrick Seed, a professor of pediatrics and
microbiology-immunology at the Northwestern University Feinberg School
of Medicine, Hartmann’s lab learned from Raoultella planticola.
Naturally occurring in the human gut in low abundances, Raoultella
planticola can break down chemotherapy drug doxorubicin, which has been
demonstrated in other research.
test whether or not this breakdown effect could protect the entire
microbiome, the team developed simplified microbial communities, which
included various types of bacteria typically found in the human gut. The
“mock gut communities” included bacteria strains (Escherichia coli and
Klebsiella pneumoniae) that are good at breaking down doxorubicin,
strains (Clostridium innocuum and Lactobacillus rhamnosus) that are
especially sensitive to doxorubicin and one strain (Enterococcus
faecium) that is resistant to doxorubicin but does not break it down.
team then exposed these mock gut communities” to doxorubicin and found
increased survival among sensitive strains. The researchers concluded
that, by degrading doxorubicin, certain bacteria made the drugs less
toxic to the rest of the gut.
the research highlights a promising new pathway for potentially
protecting cancer patients, Hartmann cautions that translating the new
findings into treatments is still far off.
are several eventual applications that would be great to help cancer
patients — particularly pediatric patients — not experience such harsh
side effects,” she said. “But we’re still far from actually making that a
Source: Northwestern University