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EXPERT REACTION: A stem cell-based multi-cancer vaccine shows promise in mice

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US scientists say it may be possible to prime the body to protect and fight against multiple types of cancer using a vaccine made from inactivated induced pluripotent stem cells (iPSCs) - adult cells that have been reprogrammed to mimic stem cells, the cells that can go on to become any other type of body cell. 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. The vaccine, which was combined with an immune booster based on a snippet of DNA from a bacterium, worked for breast, lung and skin cancer cells, and also stopped relapses in mice that had tumours removed. The authors say antigens present on inactivated iPSCs are also present on cancer cells, so priming the body with iPSCs also appears to prime it to fight cancers.

Journal/conference: Cell Stem Cell

Organisation/s: Stanford University, USA

Funder: The California Institute of Regenerative Medicine (CIRM) and the National Institutes of Health (NIH).

Media Release

From: Cell Press

Stem cell vaccine immunizes lab mice against multiple cancers

Stanford University researchers report that injecting mice with inactivated induced pluripotent stem cells (iPSCs) launched a strong immune response against breast, lung, and skin cancers. The vaccine also prevented relapses in animals that had tumors removed. The work appears in the journal Cell Stem Cell on Feb. 15.

iPSCs are generated from adult cells genetically reprogrammed to mimic embryonic stem cells' ability to become any type of cell in the body.

In the study, 75 mice received versions of the iPSC vaccine created from iPSCs that have been inactivated by irradiation. Within four weeks, 70 percent of the vaccinated mice fully rejected newly introduced breast cancer cells, while the remaining 30 percent had significantly smaller tumors. The effectiveness of the iPSC vaccine was also validated for lung and skin cancers.

Lead author Joseph C. Wu at Stanford's Cardiovascular Institute and Institute for Stem Cell Biology and Regenerative Medicine and colleagues found that a large amount of the antigens present on iPSCs are also present on cancer cells. When lab mice were vaccinated with iPSCs, their immune systems built an immune response to the antigens on the iPSCs. Because of key similarities between the iPSCs and cancer cells, the animals simultaneously built an immune response against cancer.

The iPSCs seemed to "prime their immune systems to eradicate tumor cells," Wu says.

To be effective, anti-cancer vaccines must introduce one or more antigens into the body that activate T cells or produce antibodies capable of recognizing and binding to antigens on the surfaces of cancer cells.

One of the biggest challenges for cancer immunotherapies is the limited number of antigens that can be presented to the immune system at a given time. The Stanford study uses an animal's own cells to create an iPSC-based cancer vaccine that simultaneously targets multiple tumor antigens. Using whole iPSCs eliminates the need to identify the most optimal antigen to target in a particular type of cancer.

"We present the immune system with a larger number of tumor antigens found in iPSCs, which makes our approach less susceptible to immune evasion by cancer cells," Wu says. The researchers also combined iPSCs with an immunity booster--a snippet of bacterial DNA called CpG that has been deemed safe in human trials. Stanford oncologist and study co-author Ronald Levy previously found CpG to be a potent tumor-fighting agent.

In the future, a patient's skin or blood cells may be re-programmed into iPSCs and administered as an anti-cancer vaccine or as a follow-up booster after surgery, chemotherapy, or radiation therapy.

"What surprised us most was the effectiveness of the iPSC vaccine in re-activating the immune system to target cancer," Wu says. "This approach may have clinical potential to prevent tumor recurrence or target distant metastases."

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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives and reflect independent opinion on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Andrew Laslett is a Research Team Leader at CSIRO Materials Science and Engineering.

Scientists from Stanford University in California have demonstrated, using mice, that it might be possible to protect against different types of cancer by injecting inactivated stem cells as a vaccine.

This is because some proteins found on the cell surface of stem cells are also found on the surface of cancer cells.

In a relatively simple set of experiments, the scientists have shown that vaccination of experimental mice with induced pluripotent stem cells, made from genetically identical mice, could prevent or slow breast, skin or lung cancer in the majority of experiments carried out.

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.

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.

Last updated: 15 Feb 2018 11:19am

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  • Postdoctoral researcher Nigel Geoffrey Kooreman explains the research.

    Postdoctoral researcher Nigel Geoffrey Kooreman explains the research.

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    Last Modified: 16 Feb 2018 5:52pm

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