Disease-causing bacteria Salmonella could be used to fight bowel cancer, as scientists make a breakthrough discovery.
Bowel cancer is the second most common cause of cancer death in the UK with around 16,800 deaths a year — making finding new ways of tackling the disease vital.
While bacteria, such as the food poisoning bug Salmonella, has been the focus of previous research, it has always had limiting success.
That’s because while the bacteria does have a suppressant effect on tumour cell growth, it also suppresses a part of our immune system which is essential to fight tumours.
However, a new finding by Cancer Research UK funded researchers in Glasgow and Birmingham, has pinpointed the mechanism that causes the immune system to be suppressed and has found a potential solution.
The paper, published in the journal EMBO Molecular Medicine, studied the response of T cells — a type of immune cell that helps protect the body from cancer — to a specially engineered safe form of Salmonella in mice with colorectal cancer.
Researchers found Salmonella prevents T cells from doing their job and stopping colorectal cancer cells in their tracks.
The team discovered that the Salmonella depleted an amino acid called asparagine which suppresses tumour growth, also suppresses T cells by stopping their metabolic processes.
Researchers discovered that the Salmonella depleted an amino acid called asparagine which suppresses tumour growth, also stops T cells from doing their job
Lead researcher Dr Kendle Maslowski, of the Cancer Research UK Scotland Institute in Glasgow and the University of Glasgow, pictured, believes the findings show the bacteria could be engineered to help fight cancer
But they believe that Salmonella bacteria could be further engineered to work alongside the body’s immune system, so T cells continue to attack cancer cells alongside the bacteria suppressing tumour growth.
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.’
First author, Dr Alastair Copland, Research Fellow in Immunology at the University of Birmingham, added: ‘It’s particularly rewarding to turn a disease-causing bug like Salmonella into one that combats cancer.’
While using bacteria to fight cancer has been researched by scientists since the 19th century, the dangers to health posed by bacteria meant it wasn’t explored further.
But recent advances in genetic modification to make bacteria safe to use, has sparked a resurgence of research in this area.
Director of research at Cancer Research UK, Dr Catherine Elliott, said: ‘Bacterial therapies have not become mainstream despite the massive strides we are making with immunotherapies which use our own bodies’ immune system to attack cancer.
‘But the power of bacteria has long been acknowledged as likely to hold significant potential to tackle disease.
‘This exciting development from the Cancer Research UK Scotland Institute could lead to more effective treatments for patients with colorectal, and other cancers in future, providing hope for patients.’
