Early success in stem cell cancer plan
US researchers are developing a stem cell-based multi-cancer vaccine.
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 tumours removed.
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 per cent of the vaccinated mice fully rejected newly introduced breast cancer cells, while the remaining 30 per cent had significantly smaller tumours.
The effectiveness of the iPSC vaccine was also validated for lung and skin cancers.
The research was based on an earlier discovery 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 tumour cells,” Stanford researcher Joseph 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 recognising 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 tumour antigens.
Using whole iPSCs eliminates the need to identify the most optimal antigen to target in a particular type of cancer.
The experts say that 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.