Salmonella discovery offers new hope for bowel cancer therapies

Researchers at the University of Birmingham, in collaboration with the University of Glasgow, have identified a mechanism that could unlock the potential of bacterial therapies to fight bowel cancer. 

This new research, funded by Cancer Research UK, explores how specially engineered Salmonella bacteria can work alongside the immune system to tackle cancer. Published in EMBO Molecular Medicine, the findings could pave the way for new therapies targeting bowel cancer, the UK’s second leading cause of cancer-related deaths.

The study focuses on the interaction between the immune system’s T cells — key defenders against cancer — and a modified, safe strain of Salmonella in mice with colorectal cancer. 

The research team have discovered that Salmonella depletes asparagine, a vital amino acid. While this slows tumour growth, it also suppresses the metabolic processes of T cells, preventing them from attacking cancer cells. The researchers propose genetically engineering bacteria to avoid targeting asparagine, enabling T cells to work effectively alongside the bacterial treatment.

Dr Alastair Copland, first author and Research Fellow in Immunology at the University of Birmingham, said: "Bacterial therapies are an exciting way to treat cancer by essentially starving tumours of vital nutrients. One longstanding mystery has been why T cells, which are key to fighting cancer, don’t function optimally during this treatment.

“Now, we’ve identified the protein responsible for this, and pinpointed an exciting genetic target that could help us unleash the full potential of this therapy. It’s particularly rewarding to turn a disease-causing bug like Salmonella into one that combats cancer.”

Dating back to 19th century

While bacterial therapies date back to the 19th century, they were historically set aside due to safety concerns. Advances in genetic modification have recently renewed interest, with researchers aiming to make bacteria safe and effective tools in cancer treatment.

Lead researcher Dr Kendle Maslowski, of the Cancer Research UK Scotland Institute in Glasgow and the University of Glasgow, said: “We know attenuated Salmonella and other bacteria have the power to tackle cancer, however until now it was not known why it was not proving as effective as it should be.

"Our research has discovered that it is an amino acid called asparagine that the bacteria attacks which is essential for T cells to be activated. We believe this knowledge could enable bacteria to be engineered not to attack asparagine allowing the T cells to act against the tumour cells leading to new effective treatments for cancer.”

With around 16,800 deaths annually in the UK due to bowel cancer, innovations like this offer renewed hope in the fight against the disease.