Cancer vaccine using "zombie" cells shows promise in mouse tests
An ounce of prevention is worth a pound of cure, so they say. Scientists have now demonstrated a new potential cancer vaccine that involves injections of dormant tumor cells to stimulate the immune system and help prevent the onset of cancer.
A cancer vaccine would be something of a Holy Grail to modern medicine, and unsurprisingly much work is directed towards this goal. Some techniques would be therapeutic, fighting cancer that’s already present in a patient, while others could be preventative, designed to reduce the risk of cancer forming in the first place. Either way, these vaccines would work by stimulating the immune system to recognize cancer.
Now, scientists at the Institute for Research in Biomedicine (IRB) Barcelona have developed a new type of cancer vaccine. Previous versions have been designed to stimulate the immune response by administering dead tumor cells, but in the new study the team found more success using cancer cells in a dormant state known as senescence.
As cells age and accumulate DNA damage, they eventually reach a point where they stop dividing, but instead of dying off they lie dormant. These so-called senescent (or "zombie") cells are implicated in many of the symptoms of aging, but they appear to be a protective mechanism against cancer, which is essentially uncontrolled cell division.
So for the new study, the IRB team investigated whether senescent tumor cells could be used instead of dead ones to stimulate an immune response. After all, they still have the same markers that immune cells are on the lookout for, but without the risk of them growing and dividing.
The researchers vaccinated healthy mice with senescent tumor cells, then one week later injected them with live melanoma or pancreatic cancer cells. And sure enough, the number of mice that went on to develop tumors was significantly reduced in the group that received senescent tumor cells, compared to controls inoculated with cancer cells in the process of dying.
The team also administered the senescent cell vaccines to mice that already had developed tumors, and found some improvements there too, albeit not to the same extent as the prophylactic treatment.
Closer examination revealed that the senescent cells were highly efficient in stimulating important immune cells – dendritic cells and CD8 T cells – against the cancer.
“Our study concludes that the induction of senescence in tumor cells improves the recognition of these cells by the immune system and it also increases the intensity of the response they generate,” said Inés Marín, first author of the study. “So our findings are very positive.”
Of course, results in animal models don’t always translate to humans, so there’s still plenty of work left to do. The team is currently testing how well the senescent cell vaccine might work in combination with immunotherapy treatments – a one-two punch that’s shown promise in other studies.
The research was published in the journal Cancer Discovery.
Source: IRB Barcelona