Is A Universal Cancer Vaccine Closer Than We Think?
An international team of scientists has published the first results on what some experts are calling a “universal” cancer vaccine. Early findings are “very positive,” according to lead researcher Ugur Sahin of Johannes Gutenberg University in Germany, who spoke to the Independent on June 1.
After Well-Tolerated Test In Three Patients, Vaccine Moves Forward
In their study, the researchers isolated portions of genetic material from the cancer cells of three melanoma patients. After encasing this genetic material in tiny particles of fat, the scientists injected the resulting “RNA-lipoplexes” back into the patient’s bloodstream.
While the new immunotherapy technique operates like the vaccines we’re all familiar with, it won’t be administered to cancer-free patients, inoculating them from the disease before they get it. Instead, patients who already have cancer are the ones who could benefit from the innovations reported on June 1, 2016 in the journal Nature.
Dendritic Cells: Optimizing The Body’s Surveillance System
The point is to activate so-called dendritic cells, true marvels of the immune system that constantly monitor their environment for signs of disease.
If you’re going to stimulate one part of the immune system, make it a dendritic cell. While macrophages and B cells are able to activate memory T cells, ones that have already learned to recognize a particular antigen, dendritic cells are able to rouse both memory T cells and naive T cells. In this case, innocence is a virtue. Because they haven’t been activated by prior invasions, naive T cells are able to respond to novel pathogens, intruders the immune system has never encountered before.
After spotting a virus, bacterium or cancer cell, the dendritic cell eats it, degrading the proteins of which the invader was made into small fragments. From here, the cell travels to a lymph node, where it unfurls the recently-digested bits of disease as projections on its surface. These “antigens” alert other elements of the immune system, most notably helper and killer T-cells, to the presence of foreign dangers.
Until now, researchers were struggling to find a way of introducing cancer antigens to dendritic cells. Apparently, encasing a cancer cell’s genetic material in nanoparticles of fat may be the trick, striking the right balance between protecting the genetic material’s integrity during travel and providing the dendritic cells with something they can digest easily. By playing with the ratio of fat to RNA, the researchers were actually able to impart the total package a mild negative charge, which “leads” the nanoparticle to lymph nodes.
Unraveling Cancer’s Genetic Code
To be clear, the researchers aren’t mobilizing actual antigens, but the RNA (a type of genetic information) that cancer cells use to create their antigens.
This, though, is what gives the cancer vaccine such vast potential. By simply altering the genetic code, scientists may be able to “program” the RNA to produce any number of cancer antigens, and thus prime the immune system to recognize different types of cancer. Theoretically, doctors won’t need any samples of a patient’s cancer to create the vaccine. All they’ll need is the right genetic code.
Right, however, is the key. Cancer cells often produce antigens that healthy cells also manufacture, leading to weaker immune responses. To this point, identifying cancer-specific antigens has been a major hurdle in immunotherapy, one the international researchers may have overcome.
Mice & Other Limitations
Perhaps best of all, especially in light of recent drastic increases in the cost of new cancer treatments, the researchers say their vaccine is “fast and inexpensive to produce.”
Alan Melcher, a professor of clinical oncology at the University of Leeds, took a more cautious approach to the results, noting “uncertainty” about whether the vaccine’s positive effects in mice would carry over to human patients. “Manufacturing nanoparticles for widespread clinical application” will be another, more logistical, challenge entirely, Melcher told the Independent.
At any rate, the three melanoma patients who received the vaccine seem to have tolerated the technique well, experiencing only mild flu-like symptoms. But this is still very new science, and we should be careful to temper our hopes for a true “breakthrough,” which is how many media sources have described the recent trial. We still don’t understand whether or not the vaccine actually helps to kill cancer; that’s the question of a 12-month follow-up trial currently ongoing.
That being said, the method has proven effective in mice, especially rodents that have developed “aggressively growing” tumors, the researchers write. Mice, though, aren’t always a good predictor of how humans will react. In fact, they’re usually pretty bad predictors. In their 2014 study, “Lost In Translation,” health scientists in Ontario found that less than 8% of the cancer treatments found to be effective in animal models (usually mice or rats) successfully translate to human applications.