Bacteria Found in Tumors Could Boost Chemotherapy Effectiveness

Scientists have discovered that bacteria inside tumors produce a molecule, 2-MiCit, that enhances chemotherapy by damaging cancer cells and disrupting metabolism. The finding could inspire new, microbe-based cancer treatments.

Tiny Allies in the Fight Against Cancer

In a groundbreaking discovery, scientists have found that bacteria living inside tumors can produce a molecule that weakens cancer cells and boosts chemotherapy. The molecule, called 2-methylisocitrate (2-MiCit), damages cancer cell DNA and disrupts their metabolism, making them more vulnerable to treatment.

Bacteria: The Unexpected Cancer Fighters

Researchers from the MRC Laboratory of Medical Sciences (LMS) at Imperial College London and the University of Cologne discovered that microbes found within tumors are not just passive passengers—they may actively influence cancer progression and therapy response.

Tumors host unique bacterial communities, and this new study reveals that these bacteria can produce chemicals that enhance the effectiveness of chemotherapy drugs.

The Discovery of 2-MiCit

The research, published in Cell Systems , identified 2-MiCit, a powerful anti-cancer metabolite produced by E. coli bacteria associated with colorectal cancer.

Using an advanced large-scale screening system, scientists tested more than 1,100 conditions in C. elegans worms and found that 2-MiCit significantly improved the effectiveness of the chemotherapy drug 5-fluorouracil (5-FU).

Further experiments in human cancer cells and fruit flies confirmed that 2-MiCit had strong anti-cancer properties and extended survival in the fly model.

How the Molecule Works

Professor Filipe Cabreiro, head of the Host-Microbe Co-Metabolism group at the LMS, explains:

“We’ve known that bacteria are associated with tumors, but now we’re beginning to understand the chemical conversation they’re having with cancer cells.”

The molecule 2-MiCit targets the mitochondria, the energy hubs of cancer cells. By disrupting mitochondrial enzymes, it causes DNA damage and slows cancer growth. When combined with chemotherapy, this dual attack proved far more effective than either approach alone.

Enhancing Nature’s Design

Lead author Dr. Daniel Martinez-Martinez noted that the discovery underscores the deep connection between microbes and human biology:

“It’s incredible that a single molecule from bacteria can have such a major effect on cancer progression.”

Collaborating with medicinal chemists, the team engineered a synthetic version of 2-MiCit, enhancing its potency. This improved compound showed even stronger cancer-killing effects, paving the way for new drug development inspired by nature’s own chemistry.

Toward Personalized Cancer Therapies

This research demonstrates how the tumor microbiome—the ecosystem of bacteria living within tumors—can influence treatment outcomes. It also highlights the potential of personalized medicine, where both the patient and their microbes are considered in therapy design.

Funded by the Leverhulme Trust, the Wellcome Trust/Royal Society, the DFG German Research Foundation, and the Medical Research Council, the study marks an exciting step toward harnessing our internal microbes to fight cancer.