FEB 24, 2018 12:50 PM PST

Tumors Eradicated by Immune-stimulating Agents

WRITTEN BY: Carmen Leitch

With mice as a model, researchers at Stanford discovered that by injecting two molecules that stimulate the immune system, solid tumors and any trace of cancer could be eliminated. This T cell activating therapy could work for many types of cancer. Because only small amounts are needed in a targeted approach, the researchers believe this could be an affordable treatment that doesn’t cause as many side effects as other therapeutics.

A scanning electron micrograph of a healthy human T cell. / Credit: NIH

“When we use these two agents together, we see the elimination of tumors all over the body,” noted Ronald Levy, MD, professor of oncology. He was senior author of a report in Science Translational Medicine summarizing the findings. “This approach bypasses the need to identify tumor-specific immune targets and doesn’t require wholesale activation of the immune system or customization of a patient’s immune cells.”

One drug is already approved for human use, and the other has undergone testing for human patients in a few unrelated clinical trials. This January, a new clinical trial was launched to assess this treatment in lymphoma patients.

There has been considerable interest in developing drugs that use the immune system to fight cancer. Some approaches rely on bodywide stimulation; others remove a patient’s immune cells and genetically alter them to combat cancer before reinjecting them. While there have been other attempts as well, none have been entirely successful. Some are very expensive or laborious; others cause serious side effects. 

“All of these immunotherapy advances are changing medical practice,” Levy said. “Our approach uses a one-time application of very small amounts of two agents to stimulate the immune cells only within the tumor itself. In the mice, we saw amazing, bodywide effects, including the elimination of tumors all over the animal.”

Typically, cells of the immune system that should recognize foreign invaders, T cells, will attack cancer cells at first, but as cancerous tumors grow, they are often able to suppress T cell activity.

Levy’s team aimed to stimulate T cells that target cancer by exposing them to minuscule amounts of two agents at the site of tumors. One is a short snippet of DNA called an oligonucleotide; it boosts the expression of a T cell receptor. The other molecule is an antibody that binds to that receptor. Together, the antibody and receptor team up to activate the T cells. Only T cells that have gotten into the tumor are activated since the agents are applied to the tumor directly. Those T cells can recognize a specific cancer, and some leave the site of the tumor. They then migrate throughout the body and destroy other, similar tumors.

This was a remarkably effective approach that worked in transplanted lymphoma tumors, with both the original injected tumor getting destroyed as well as a second, uninjected tumor. The therapy also worked on genetically engineered mice that develop breast cancer. In the cases of cancers that grew back after the first treatment, a second treatment removed it again.

After testing mice that had been transplanted to receive lymphoma tumors and colon cancer, the treatment eliminated the lymphoma tumors, but not the colon cancer.

“This is a very targeted approach,” Levy explained. “Only the tumor that shares the protein targets displayed by the treated site is affected. We’re attacking specific targets without having to identify exactly what proteins the T cells are recognizing.”

If the current trial, which will have around fifteen lymphoma patients, is successful, the researchers want to find out if it works with other kinds of cancer.

“I don’t think there’s a limit to the type of tumor we could potentially treat, as long as it has been infiltrated by the immune system,” Levy said.

Sources: Stanford University, Science Translational Medicine

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JAN 24, 2020
Cell & Molecular Biology
JAN 24, 2020
Linking Intestinal Stem Cells with Increased Cancer Risk From a High-Fat Diet
The work, which used a mouse model, links stem cell activity with cellular fat consumption in a new way....
JAN 24, 2020
JAN 24, 2020
Protecting Killer Immune Cells from Themselves
Destroying human cells compromised by viruses and cancer is the name of the game for so-called “killer” cells of the immune system. They employ...
JAN 24, 2020
Cell & Molecular Biology
JAN 24, 2020
Using a Bacterial Syringe to Deliver Proteins to Cells
Researchers want to use a pathogen's strategy for therapeutic purposes....
JAN 24, 2020
JAN 24, 2020
Potential Therapeutics for Nipah Virus Are Identified
The fatality rate of Nipah virus has an estimated range of 40 to 75 percent...
JAN 24, 2020
Genetics & Genomics
JAN 24, 2020
Can We Cure Down's Syndrome with Gene Therapy?
Down’s Syndrome (DS) is a genetic disorder brought on by the presence of all of part of a third copy of chromosome 21. Linked to delays in physical g...
JAN 24, 2020
Cell & Molecular Biology
JAN 24, 2020
Repurposing Existing Drugs to Treat Cancer
Drugs have to be rigorously tested before they can be offered to patients, so it can be much easier to find more than one application for a medication....
Loading Comments...