Researchers at the University of Waterloo have developed a groundbreaking method utilizing bacteria to combat cancer tumors from the inside. Dr. Marc Aucoin, a chemical engineering professor, explains that the process involves Clostridium sporogenes, a bacterium that thrives in oxygen-free environments. This microbe enters the tumor, where it finds abundant nutrients and begins to grow, effectively colonizing the tumor's core and helping to eliminate it.
The unique characteristic of Clostridium sporogenes is its ability to survive in the dead cell regions of solid tumors, which are devoid of oxygen. However, a significant challenge arises when the bacteria expand into areas with trace amounts of oxygen, leading to their premature death before they can completely eradicate the cancer.
To enhance the bacteria's effectiveness, the research team incorporated a gene from a more oxygen-tolerant bacterium. This genetic modification enables the engineered microbes to endure longer in the oxygen-rich outer regions of the tumor. Moreover, the researchers implemented a control mechanism to regulate the activation of this oxygen-tolerance feature, ensuring it only activates when necessary. This is achieved through a process known as quorum sensing, where bacteria communicate via chemical signals that increase as their population grows.
Once a sufficient number of bacteria accumulate within the tumor, the chemical signal triggers the oxygen-tolerant gene, allowing the bacteria to thrive without risking growth in the bloodstream, which could lead to serious health complications.
In previous studies, the team demonstrated the potential of genetically altering Clostridium sporogenes to better withstand oxygen. They also tested their quorum sensing design by programming the bacteria to produce a green fluorescent protein, confirming that the system activates at the desired moment.
Dr. Brian Ingalls, a professor of applied mathematics, likened their work to constructing an electrical circuit using DNA segments instead of wires, where each segment has a specific function. The goal is to integrate both the oxygen-tolerance gene and the quorum-sensing control into a single bacterium for pre-clinical trials against tumors.
This innovative research began under the guidance of PhD student Bahram Zargar, alongside Dr. Ingalls and Dr. Pu Chen, a retired professor at Waterloo. It showcases the university's commitment to interdisciplinary health innovation, merging expertise from engineering, mathematics, and life sciences to transform scientific breakthroughs into practical medical applications.
The Waterloo team is collaborating with the Center for Research on Environmental Microbiology (CREM Co Labs) in Toronto, co-founded by Dr. Zargar, along with Dr. Sara Sadr, a former Waterloo doctoral student instrumental in advancing this research.
