Scientists engineer bacteria to destroy cancer from within

Thursday 26 February 2026 - 09:20

By: Dakir Madiha

Scientists engineer bacteria to destroy cancer from within

Researchers at the University of Waterloo have developed modified bacteria capable of infiltrating and consuming solid tumors, offering a potential breakthrough in non-surgical cancer therapy. Their study, published in ACS Synthetic Biology, builds on years of work using microbes to selectively target cancerous tissue while sparing healthy cells.

The team engineered Clostridium sporogenes, a soil-dwelling bacterium that thrives in oxygen-free environments, to naturally seek out and grow inside the cores of solid tumors. These oxygen-deprived zones, filled with dead cells and nutrients, provide an ideal habitat where the bacteria multiply and degrade tumor material from the inside out. As the bacteria expand, they reduce tumor volume until they reach oxygenated outer layers, where the microbes typically die off.

To help the bacteria survive long enough to complete the process, the researchers introduced a gene called noxA from a related species. This gene enables limited oxygen tolerance, allowing the bacteria to function closer to tumor edges. However, to maintain safety and prevent uncontrolled spread, the team refined the mechanism to ensure the oxygen-resistance gene activates only after the bacteria have successfully colonized the tumor’s core.

This was achieved using quorum sensing a form of bacterial communication where cells trigger genetic responses only when their population reaches a certain density. The scientists designed a genetic "circuit" that ensures the noxA gene switches on exclusively within dense bacterial clusters inside the tumor, keeping the engineered microbes dormant in oxygen-rich areas such as the bloodstream.

The researchers plan to merge this self-regulating system with the oxygen-tolerance gene into a single strain for pre-clinical testing. The project originated from doctoral work by Bahram Zargar and involves collaboration with the Toronto-based Center for Research on Environmental Microbiology (CREM Co Labs), co-founded by Zargar, with support from former Waterloo researcher Sara Sadr. The team aims to develop the method into a precise, controllable therapy targeting hard-to-treat cancers.