Salmonella is one of the most common forms of food poisoning, leaving victims bedridden with some pretty nasty symptoms.
But what if, rather than attacking the human gut, the militant bacteria could be modified to tackle one of the most aggressive forms of cancer?
That’s the thinking behind an extraordinary new study in which scientists genetically engineered salmonella to fight brain tumours.
Researchers from Duke University used the novel treatment on rats with glioblastoma, and saw significant increases in lifespan.
Around 20 per cent of rodents survived 100 days longer than those without it.
That’s equivalent to 10 years in humans terms.
“Since glioblastoma is so aggressive and difficult to treat, any change in the median survival rate is a big deal,” said Johnathan Lyon, a PhD student and co-author of the study. “Since few survive a glioblastoma diagnosis indefinitely, a 20 percent effective cure rate is phenomenal and very encouraging.”
So how does it work?
In their own words, the researchers turned the bacterium into a “cancer-seeking missile that produces self-destruct orders deep within tumours”.
A series of genetic tweaks triggered the bacteria to produce compounds that instruct cells to commit suicide.
Critically, this only happens in the presence of low levels of oxygen. Because tumours tend to have unusually low oxygen, the bacteria targets the cancer, but not the healthy cells around it.
“A major challenge in treating gliomas is that the tumour is dispersed with no clear edge, making them difficult to completely surgically remove,” said Bellamkonda. “So designing bacteria to actively move and seek out these distributed tumours, and express their anti-tumour proteins only in hypoxic, purine rich tumour regions is exciting.”
The researchers now hope to program the bacteria to produce drugs that have an even stronger impact on the tumours.
The study appeared in the latest edition of the journal Molecular Therapy – Oncolytics.