The Role of Microbes in Cancer Treatment
With increasing awareness of bacteria living on the skin or within the gut, new scientific research reveals the presence of distinct bacterial communities within tumors themselves. Scientists are now exploring how these tumor-associated microbes affect tumor growth and cancer response to treatment.
Exploring the Link Between Microbes and Cancer
A new study published in the journal “Cell Systems” on September 10, 2025, by a team of researchers identified a potent anti-cancer metabolite produced by bacteria associated with colorectal cancer. This discovery marks a significant advancement in understanding the relationship between microbes and cancer and could lead to the development of new drugs designed to make chemotherapy more effective.
Using an advanced high-throughput screening method, researchers tested over 1,100 cases in a small worm known as “Caenorhabditis elegans,” commonly used in research. They discovered that “E. coli” bacteria produce a molecule called 2-methylisocitrate (2-MiCit), which enhances the potency of the chemotherapy drug 5-fluorouracil (5-FU).
The Mechanism of Microbial Metabolites
Computational models showed that the tumor-associated microbiome (the bacterial community within and around tumors) in human patients can also produce 2-MiCit. The team confirmed the effects of the molecule using human cancer cells and a fruit fly model of colorectal cancer. In both systems, 2-MiCit demonstrated strong anti-cancer activity, even increasing survival in the flies.
Professor Philip Cabreiro, head of the Host-Microbe Interaction Group at LMS and group leader at the CECAD Research Group in Cologne, described the discovery as a revolutionary advancement. He noted that bacteria can be a powerful partner for chemotherapy, disrupting the metabolism of cancer cells and making them more susceptible to the drug.
The Impact of 2-MiCit on Cancer Cells
The study revealed that 2-MiCit works by inhibiting a key mitochondrial enzyme (mitochondria are structures within cells that produce energy). This intervention causes DNA damage and triggers cellular pathways that slow cancer progression. By weakening cancer cells and enhancing the effects of chemotherapy simultaneously, the combination of 2-MiCit and 5-FU proved to be much more effective than either treatment alone.
Dr. Daniel Martinez-Martinez, a postdoctoral researcher at LMS and the first author of the paper, explained that microbes are an integral part of us. The ability of a single molecule to have a significant impact on cancer progression is astonishing, providing further evidence of the complexity of biology when viewed from a holistic perspective.
Chemical Development of Compounds
In collaboration with medicinal chemists, researchers also modified the 2-MiCit compound to enhance its efficacy. This synthetic version proved to be more potent in killing cancer cells, demonstrating the potential for developing new drugs based on natural microbial products. Philip added, “Using the natural microbial product as a starting point, we were able to design a more powerful molecule, effectively improving on nature.”
Conclusion
These exciting discoveries highlight how the cancer-associated microbiome influences tumor progression and how the metabolites produced by these bacteria can be used to improve cancer treatments. These findings are highly significant in the context of personalized medicine, emphasizing the importance of considering not only the patient’s condition but also their specific microbes.