Researchers at the University of Waterloo have made a groundbreaking advancement in cancer treatment by engineering bacteria known as Clostridium sporogenes to consume tumors from within. This innovative approach aims to offer a new alternative to traditional cancer therapies, including chemotherapy and radiation.
The engineered bacteria thrive in oxygen-free environments, making solid tumors, which are often devoid of oxygen and filled with dead cells, an ideal habitat for their growth. According to Marc Aucoin, a chemical engineering professor and coauthor of a recent study published in ACS Synthetic Biology, the spores of these bacteria infiltrate the tumor, feeding on the nutrients available. “We are now colonizing that central space, and the bacterium is essentially ridding the body of the tumor,” Aucoin explained.
This method seeks to address the limitations of conventional cancer treatments, which often come with harmful side effects. The potential of bacteria to trigger an immune response against cancer cells also presents a promising avenue for treatment. Christopher Johnston, a researcher in genomic medicine at the University of Texas, noted, “Using ‘bugs as drugs’ offers a promising solution to overcome some of the challenges with traditional cancer therapies.” He emphasized the complexities of treating solid tumors, which account for the majority of adult cancers.
In related studies published in 2024, scientists found that genetically modified E. coli could shrink tumors in mice, while engineered strains of Salmonella have shown the ability to kill cancer cells. The Waterloo team, however, faced significant challenges in their research. One major issue was the bacteria’s vulnerability to oxygen exposure at the tumor’s edge, which could lead to their death.
To combat this, Aucoin and his colleagues genetically modified the C. sporogenes to tolerate some levels of oxygen. This adaptation allows the bacteria to survive near the tumor’s outer edges. Their recent follow-up study detailed the implementation of a technique called “quorum sensing.” This method enables the bacteria to activate the oxygen-resistant gene only after sufficiently multiplying inside the tumor, enhancing their chances of eliminating it.
The research team also engineered the bacteria to produce a green fluorescent protein, providing a visible signal of their successful colonization and function within the tumor. Brian Ingalls, an applied mathematics professor at Waterloo, described their approach as building “something like an electrical circuit, but instead of wires we used pieces of DNA.” This innovative assembly allows for a predictable and effective system.
Currently, the research is in its early stages, with thorough testing in human subjects yet to be conducted. The Waterloo team is optimistic about merging the findings from their studies on genetic modification and quorum sensing into a single bacterial strain. They plan to advance this research into pre-clinical trials, potentially paving the way for a novel cancer treatment.
As the scientific community explores the capabilities of engineered bacteria, the future of cancer treatment may increasingly rely on these microscopic organisms. With ongoing research and development, the hope is to harness their unique properties to combat one of the most challenging diseases facing humanity.
