Promising cancer vaccine would use patient’s own cells to train the immune system

Tested in lab mice, the stem cell vaccine was highly effective against multiple types of cancer.

Adult cells reprogrammed to act like embryonic stem cells could serve as a vaccine against cancer, Stanford University researchers have found. The researchers injected mice with a vaccine made from these reprogrammed cells, triggering an immune response. Because the cells share proteins with cancer cells, the mice’s immune systems began to reject cancer cells as well. The method proved effective against multiple types of cancer in mice, leaving researchers hopeful it could one day be used to vaccinate humans. We spoke with study author Joseph Wu to learn more.

ResearchGate: What are induced pluripotent stem cells (iPSCs), and how are they typically used?

Joseph Wu: iPSCs are created by reprogramming the nucleus of an adult somatic cell, like a skin cell or blood cell, to express similar genes as embryonic stem cells. By doing so, the adult somatic cell actually transforms into a cell that is similar to embryonic stem cells. These can then be differentiated into a large number of other cell types in the human body, like heart muscle cells, nerve cells, pancreatic cells, liver cells, etc. The main applications of these cells include understanding disease mechanism, drug discovery, and regenerative medicine.

RG: How did you use them in your study?

Wu: In our study, we use the iPSCs in combination with an immunostimulant agent to create a vaccine to activate the immune system to target the proteins on iPSCs. The rationale behind the vaccine is the overlap in proteins that are present on both cancer cells and iPSCs. So when you activate the immune system to target the proteins on the iPSCs, it makes them also attack the cancer cells that have the same set of proteins.

RG: What were the results?

Wu: For all cancers, the treatment worked very well. For breast cancer for instance, it resulted in complete rejection of the cancer in 70 percent of the mice. Even with the large number of cancer cells we injected, the mice’s immune systems were able to fully reject or severely reduce tumors. For a very aggressive melanoma (skin cancer), it resulted in a significant reduction of tumor sizes. It might have resulted in complete rejection down the line in some of the treatment mice, but the control mice had such big tumors that we had to stop the experiment after two weeks.

RG: Do you think it would work with other types of cancer too?

Wu: We tested for skin cancer (melanoma), breast cancer, and lung cancer (mesothelioma). And yes, we believe that because of the large number of cancer-related proteins that are present on the iPSCs, this vaccine will also work on other cancers.

RG: How big of a step is this towards a cancer vaccine for humans?

Wu: We feel that this has great potential as a possible vaccine. For example, patients could be vaccinated at a certain age—say at 70—to boost their immune system to target possible cancerous cells, and limit the cancer from growing out. As a next step, we are currently setting up and performing in vitro experiments to validate the efficacy and safety of the vaccine on human samples.

Featured image courtesy of the National Cancer Institute and Cecil Fox.