Our researchers are finding out how to turn the full stomach-churning power of Salmonella away from our bowels and onto bowel cancer.
Surprising as that might sound, it’s an advance at least 200 – and possibly more than 4,000 – years in the making. Scientists first found evidence that disease-causing bacteria could have some effect on cancer in the early 1800s – long before more recognisable cancer treatments like chemotherapy or radiotherapy had even been imagined. There are even some clues to suggest that Ancient Egyptian doctors, who had multiple gods and goddesses of medicine but no microscopes, may have tried fighting cancer by causing infections.
Whenever they started, those early treatments were a crude form of what’s now called immunotherapy, which stimulates the immune system to attack cancer. There’s a good reason they went away. Treating cancer by causing a bacterial infection is risky and unreliable. Before the discovery of antibiotics, it was commonly deadly.
But things have changed. It’s now possible to genetically modify bacteria in ways that preserve their cancer-fighting potential but stop them harming cancer patients. That means researchers can explore ways of turning once-unpredictable organisms like Salmonella into standardised treatment options.
Results so far have been encouraging: modified bacteria suppress the growth of some cancers. Salmonella usually does its damage in the bowels, making it a good candidate for targeting bowel tumours. There’s just one mysterious problem: these immunotherapies don’t work with some key parts of the immune system. They seem to weaken cancers, but they don’t engage important immune cells called T cells to clear them out.
With this new study, published in the journal EMBO Molecular Medicine, a joint team at the University of Glasgow and the University of Birmingham have shown why. Their discovery could lead to a new, two-pronged cancer treatment.
by Tim Gunn , Fiona MacLeod