A new stem cell vaccine that has proven effective against malignant mesothelioma and several other cancers in mice might offer a promising new way to treat the asbestos cancer.
Although rare, malignant mesothelioma is one of the most treatment-resistant malignancies. Even with aggressive therapies, most people diagnosed with mesothelioma do not survive longer than about 18 months.
But research conducted at Stanford University and published in the journal Cell today may change that. It details the anti-tumor responses in the lab and in live mice to a vaccine composed primarily of pluripotent stem cells.
Pluripotent Stem Cells and Anti-Tumor Response
Pluripotent stem cells – also called iPS cells – are cells taken from the skin or blood that are treated with genes that “rewind their developmental clock.” The resulting cells are like immature cells without the built-in programming that turns them into all types of tissues in the body.
According to Stanford researchers, when injected into mice infected with breast cancer, mesothelioma, or melanoma, these cells essentially “prime” the immune system to attack tumors and even prevent new ones,.
“These cells, as a component of our proposed vaccine, have strong immunogenic properties that provoke a systemwide, cancer-specific immune response,” says lead study author Nigel Kooreman, MD. “We believe this approach has exciting clinical potential.”
In an article in the journal Cell, Kooreman and his colleagues explain that iPS cells are also a lot like cancer cells, which makes them ideal candidates for triggering an anti-cancer immune response.
Preventing New Mesothelioma Tumors with iPS Vaccine
Researchers tested the iPS cell vaccine on three types of cancer models – breast cancer, melanoma skin cancer, and malignant mesothelioma.
In each case, mice that had been transplanted with one of these types of cancer were injected with different vaccine combinations once a week for four weeks. The tumors shrank in size in 7 out of 10 mice that received a combination of iPS cells and an immune-stimulating agent.
The mesothelioma mice showed a marked increase in tumor-infiltrating lymphocytes, an indication of the immune system’s activation.
In a news release distributed by Stanford University today, senior author Joseph Wu, MD, PhD, explained it this way: “Although much research remains to be done, the concept itself is pretty simple. 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.”
Malignant mesothelioma is an aggressive cancer that grows on the membranes around internal organs, especially the pleura around the lungs and the peritoneum around the abdomen. Fewer than 3,000 cases are identified in the US each year and most of these patients were exposed to asbestos decades before their diagnosis.
Korreman, N, et al, “Autologous iPSC-Based Vaccines Elicit Anti-tumor Responses In Vivo”, February 15, 2018, Cell
Conger, Krista, “Induced pluripotent stem cells could serve as cancer vaccine”, February 15, 2018, Sanford University News Release