Can the technology that helped protect us from COVID-19 be used for a cancer vaccine?
Cancer cells and coronavirus infections are completely different. Thanks to mRNA (or messenger RNA) technology, however, there may eventually be a lot of similarities in how modern medicine fights them.
“Remember, people were expecting that a successful COVID-19 vaccine using mRNA would provide protective immunity to about 50% of patients,” said Dr. Herbert Kim Lyerly, George Barth Geller Distinguished Professor of Immunology at Duke University School of Medicine. “But the first two mRNA vaccines provided over 90% protection, which is a remarkable achievement.”
How Do Most Vaccines Work?
Most vaccines work by delivering either a dead or inactive version of a pathogen, or a protein from that pathogen, into the body. Immune system cells in the body recognize these key proteins in the vaccine and prime the entire system to respond quicker if it later encounters the pathogen for real.
How Are mRNA Vaccines Different?
mRNA vaccines are fundamentally different from most vaccines. mRNA, which stands for messenger RNA, works with your DNA. The genes in DNA encode protein molecules, the “workhorses” of the cell, carrying out all the functions needed for life. But to encode these proteins, DNA needs a messenger. Enter mRNA, which reads the DNA and acts as a template to form proteins.
When lab-made mRNA is injected into the body, it does the same thing. Specific proteins are produced and an immune response can be triggered.
“It is an RNA nucleic acid which encodes a specific protein that is encapsulated in something we like to call a lipid nanoparticle, which is really a little fat bubble,” said Dr. Zachary Hartman, Associate Professor in Surgery at the Duke Cancer Institute. “That nanoparticle can be injected into your body and sort of teaches your body what to go after immunologically.”
According to an article published in 2021 in Nature, the use of mRNA in vaccines stems from a history of research that began in the late 1980s.
Predictable Cancer Mutations Create an Opportunity
Duke researchers are seeking to exploit the similarities between cancer and other pathogens that mutate over time.
People with a type of breast cancer known as HER2-positive are often treated with an antibody-based drug called Herceptin. The treatment is often initially successful, but then the cancer cells evolve resistance to it and the drug stops working. This is similar to the way bacteria develop resistance to antibiotics. Only in this case, the cancer cells evolve in a very predictable manner. Specific mutations appear in specific genes.
Duke’s mRNA vaccine targets four of those known mutations. Researchers plan to test the vaccine in a small number of patients with advanced HER2-positive breast cancer. Every patient will receive the same vaccine because every one of them is expected to develop the same mutations.
“We’ll effectively be vaccinating people against mutations that their cancer doesn’t yet have,” Dr. Lyerly told the BBC’s Science Focus magazine.
Then, when the mutated cancer cells appear, the patient’s immune systems should be ready to find and destroy them. If it works, the vaccine should prevent the cancer from evolving a resistance to Herceptin. That would allow a drug that works well initially to continue working, meaning doctors would never run out of treatment options.
Researchers are already saying the mRNA vaccine, even if it proves successful in clinical trials, won’t be enough to defeat cancer. The disease is too complex.
The mRNA vaccine, however, could be used in combination with other therapies, including surgery and chemotherapy, offering a chance to not only treat certain cancers but also prevent them.
“We’re getting to a point where we can start to be proactive with cancer as well as reactive to it,” says Dr. Samuel Godfrey, the senior science communications manager at Cancer Research UK. “I think it’s phenomenally exciting.”