Scientists turn salmonella into a weapon against cancer
Scientists in South Korea have biologically weaponised salmonella bacteria so that it will essentially attack and destroy cancer cells.
Cancer is made of the body’s own cells so finding techniques to target cells for removal requires all the guile scientists and doctors can muster – and this latest breakthrough is one of the sneakiest yet.
Salmonella is more commonly known as a pathogen which causes food poisoning in humans – often ingested from undercooked chicken – but this altered version was able to trigger a powerful immune response.
The response was able to shrink cancerous tumours and, for the first time in bacterial cancer treatment, prevent the cells from spreading to other sites in the body.
These early tests were applied to human cancer cells implanted in mice – but if the same technique proves to be effective in humans it could be a big step forward for bacterial cancer treatment.
In the experiments, the scientists used a version of salmonella which is harmless but still tried to infect cells in their body. They found the immune systems of the small mammals were able to fight off the infection within three days, but the cancerous cells could not – leaving the cancer riddled with the bacteria.
After 120 days with the salmonella infection, 11 of the 20 mice tested had no signs of tumorous tissue at all.
The apparent key to the success of the test is a protein called FlaB which the salmonella was engineered to secrete.
Speaking with Science magazine the scientists said the protein makes immune cells more aggressive “changing them from Dr Jekyll to Mr Hyde”.
“This paper peels back a little bit of a window into the mechanisms perhaps by which bacterial-based therapies may be stimulating the immune system,” bacterial cancer researcher Saurabh Saha – who was not involved in the study – told The Verge.
Bacteria that is able to fight cancer was first observed by William Coley in the 1800s. He found cancer patients who developed infections after surgery to remove their tumours were actually more likely to recover than those that didn’t and began tests to find out why.
“(The study) shows that what was done 120 years ago with Coley’s Toxins deserves to be revisited again today,” said Saha.
“I think it’s a very important modality, and one that we should continue pressing forward on to learn more about.”
The research was lead by scientists from Chonnam National University in Gwangju and published in the journal Science Translational Medicine.