Hormel Institute research could make cancer-fighting vaccines a reality
A research team at the Hormel Institute recently published a study showing that a vaccine that targets melanoma reduced tumor growth in mice.
AUSTIN — What if you could train your body to fight off cancer?
This is how vaccines work, after all — the vaccination trains the immune system to respond to viruses, bacteria and other foreign bodies in order to prevent or reduce the severity of illness. But training the body's immune system to target cancer cells is more difficult, as those cells are made by the body.
But a team of scientists at the Hormel Institute is conducting studies that could lead to the development of a vaccine for melanoma, a rare but serious form of skin cancer.
"The major breakthrough of our study is that we're showing that we can indeed, by doing all this bioengineering and manipulation, we can break self-tolerance, meaning to trick the immune system to attack its own protein," said George Aslanidi, PhD, professor and leader of the Molecular Bioengineering and Cancer Vaccine research section at the institute. "It's only killing tumor cells but making no difference for the normal tissues."
Aslanidi's latest study , published online Feb. 1, 2023, in the journal "Molecular Therapy," shows this vaccine kept melanoma tumors from growing and spreading into the lungs in mice.
In humans, melanoma develops in melanocytes, the cells that give skin its color, according to the National Cancer Institute . Though it's less commonly diagnosed than other types of skin cancers, melanoma is more deadly, as it sometimes spreads into other parts of the body.
Melanoma tends to excessively express certain proteins, so Aslanidi said the vaccine works by teaching the body's immune system to attack cells making those proteins.
"It's very hard because our immune system is designed to protect our own proteins," Aslanidi said. "Even if they're developing chronic cancer cells, still our immune system wants to protect them."
The vaccine developed by Aslanidi's team gets around this issue by putting four melanoma-related proteins inside a harmless adeno-associated virus.
"This virus is very small and absolutely not pathogenic for humans or animals," Aslanidi said.
The virus acts as a vehicle to deliver these proteins into the body and produce an immune response.
While most vaccines are made to be given before a person is exposed to a virus or bacteria, a vaccine that fights melanoma would be administered after a melanoma diagnosis, Aslanidi said.
"We don't intend to preventively inject melanoma or any other vaccine against cancer because you never know what (a) particular person will be developing during their lifespan," Aslanidi said. "That's why you need to use it ... together with conventional treatment."
The next step for Aslanidi's research is studying how the vaccine works in dogs that are diagnosed with oral melanoma.
"They come into a veterinary clinic exactly the same way a patient would come," Aslanidi said. "They are undergoing exactly the same common treatment of a surgical dissection followed by radiation therapy. Then, we are implementing our vaccine and monitoring this dog for a long time."
The hope, Aslanidi said, is that the vaccine slows or stops melanoma from spreading into the dogs' lungs.
In the future, Aslanidi said this vaccine model could be used for other cancers besides melanoma, but there are additional roadblocks.
"The problem with other tumors or cancers (is) not all tumors have very definitive markers, and, most importantly, not all those markers are immunogenic," he said, meaning that those protein markers don't prompt an immune response.
But further studies will look at whether vaccines against other cancers can be developed, Aslanidi said, as well as what dose is needed, when booster vaccinations would need to be given and even how the vaccine should be administered.
"Currently, we do it intramuscular because this is the most common way to inject vaccine," like how COVID-19 and flu shots are given, Aslanidi said. "But we know that some vaccines work better if you do it intradermally or intranasally, so we need to look at the different routes of administration and see if the combination of dose and route can give a better outcome."