Last updated April 18, 2018 at 9:21 am
Immune system trained to recognise and fight off cancer in mice.
Credit: iStock
Many cancer cells behave a bit like stem cells, in that they both can grow free from the usual “off-switches” found in adult cells.
In this study, carried out in mice, researchers took cells from samples of skin or blood. The cells were then reprogrammed using four key genes that wind the cell development back to a stem cell like state called pluripotency. These Induced pluripotent cells (or iPS cells) are like stem cells in that they can be treated to turn into any kind of cell in the body.
Comparing the genes expressed in iPS cells to cancer cells revealed some remarkable similarities.
“We’ve learned that iPS cells are very similar on their surface to tumor cells,” said Joseph Wu, director of Stanford’s Cardiovascular Institute.
The similarity of the cell surfaces between iPS and cancer cells led the researchers to try using the surface molecules on iPS cells as a cancer vaccine. By training the immune system to recognise the iPS cells, it means that the system is primed to then recognise and destroy cancer cells when they appear.
They gave mice the vaccine and found it stopped tumours taking hold when the animals were injected with cancerous cells in 70 per cent of cases. The remaining 30 per cent had smaller tumours than mice that were left unvaccinated.
“When we immunized an animal with genetically matching iPS cells, the immune system could be primed to reject the development of tumors in the future. Pending replication in humans, our findings indicate these cells may one day serve as a true patient-specific cancer vaccine.”
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Putting the immune system on high alert
The strength of this approach is that it’s not just one particular type of cancer that is targeted. The iPS and cancer cells share a lot of different markers, and so the immune system can be primed to ward off lots of different types of cancers. In this study, the vaccine was effective agains breast, lung and skin cancer cells.
“Although much research remains to be done, the concept itself is pretty simple,” Wu said. “We would take your blood, make iPS cells and then inject the cells to prevent future cancers. I’m very excited about the future possibilities.”
Andrew Laslett leads a human stem cell biology research team with CSIRO, and says that the finding could be significant, but points out this is still early stage research.
“This research has, to date, only been carried out using mice. However, if translated to human medicine the implications are potentially very significant.”
“That said, mice and humans have quite different immune systems therefore this may not work in the same way when tested in human volunteers.”
Mice are great models for a lot of human diseases, and have been hugely important in the field of stem cells. But there are important differences in biology that mean that the success rate for taking treatments that work in animals to people in cancer trials is less than 8%.
“If it is shown to be effective and safe for humans it is not inconceivable to imagine a future where every person in Australia has this type of vaccination to protect against cancer” Said Laslett.
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