Cancer vaccination
Induced pluripotent stem cells (iPSCs) are used in regenerative medicine to create different types of cells and tissues.
A group of scientists from Stanford University in a study on mice demonstrated another way of using IPSC: to immunize the body against cancer.
iPSCs are similar to cancer cells: they are also undifferentiated and tend to divide and grow rapidly. The introduction of iPSCs that genetically match the recipient, but lack the ability to divide, may be a safe way to prepare the immune system to prevent cancer. These cells, as a component of a possible vaccine, have strong immunogenic properties that activate a systemic, cancer-specific immune response.
Stem cells for research can be collected from human skin or blood samples. They are reprogrammed, turning them into iPSCs.
In cancer cells, such transformations occur naturally and lead to uncontrolled and rapid division and growth.
To find out how similar iPSCs and cancer cells are, the researchers compared the gene expression of these cells in mice and humans. It was found that both cell types have similar proteins on their surface, which can be made epitopes – markers for immune cells.
In order to test their hypothesis, the authors conducted an experiment with four groups of mice. The first (control) group did not receive treatment. Mice from the second group were injected with genetically appropriate iPSCs, previously exposed to radiation to prevent the growth of teratoma – a tumor containing different types of tissues. The third group of mice received an immunostimulator used for adjuvant therapy. The fourth group is a combination of irradiated iPSCs and an adjuvant.
All animals were given drugs once a week for four weeks. After that, all groups were injected with mouse breast cancer cells to track the immune system response.
A week after cancer cell transplantation, a tumor was found in all mice at the site of cancer cell injection.
The mice in the control groups had sustained tumor growth. In the IPSC+adjuvant group, seven out of ten mice had reverse tumor development. Two mice had a complete regression of the tumor, after the experiment they lived for more than a year.
Similar results were obtained in the transplantation of melanoma and mesothelioma cancer cells (a type of lung cancer).
Administration of T-lymphocytes from vaccinated mice to mice from the control group slowed the growth of breast cancer cells. They also blocked the development of teratoma in mice injected with unirradiated iPSCs. This proves that T-lymphocytes recognized the epitopes of iPSCs and cancer cells in the same way.
There is a large amount of work to be done before implementation into clinical practice. But the concept itself is as simple as anything ingenious: you need to take a blood sample, make iPSCs and inject them into the blood. In the future, this may lead to victory over the currently incurable cancer.
Article by N. G. Kooreman et al. Autologous iPSC-Based Vaccines Elicit Anti-tumor Responses In Vivo is published in the journal Cell Stem Cell.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to Stanford Medicine News Center: Induced pluripotent stem cells could serve as cancer vaccine.