Near-Infrared Laser May Enhance Cancer Immunotherapy

Optogenetics technique harnesses immune system to reduce tumor size and metastasis.

With the promise of immunotherapy in fighting cancer, new research is examining a treatment that may potentially offer greater efficacy by using light to control the immune system.

Immunotherapy involves the body using its own immune system to battle cancer. However, researchers discovered a new method called optogenetics, which genetically engineers cells in order to produce proteins from light sensitive microbes.

This causes nerve cells to send or stop sending nerve impulses when exposed to a certain light color.

"Although neuroscientists have been using light to stimulate neurons for years, this is the first time the technique, called optogenetics, has been used in the immune system," said researcher Yubin Zhou, PhD. "Neuroscientists have learned a lot about brain circuits using the technique, and now researchers in many other fields are giving it a try."

In order to use this method on the immune system, researchers had to perform modifications to the technique. This proved to be difficult, because immune cells don’t use tiny electrical impulses to communicate like nerve cells do. Immune cells are also constantly on the move and found deep within the body, making it difficult to get light to them.

During the study published in eLife, researchers genetically engineered the immune cells to allow a gate-controlling protein to become light sensitive. They were able to achieve this by using a near-infrared laser beam that penetrates deep (1-2 centimeters) into the tissue to allow a nanoparticle to turn the light into blue light, thus forcing the gates of the protein to open.

"We collaborated with Dr. Gang Han at the University of Massachusetts Medical School who does bionanotechnology and photomedicine development," Zhou said. "Together, we were able to combine state-of-the-art optogenetic approaches with cutting edge nanotechnology. The technique reduced tumor size and metastasis, so there are lots of applications.”

The advantage of this model is that it only activates dendritic or T-cells in a part of the body that is near the draining lymph nodes or tumor. It also can be turned on and off based on need.

"Other scientists will likely use the technique to help them study immune, heart and other types of cells that use calcium to perform their tasks," Zhou said. "It's quite a cool technology. With these tools, we can now not only answer fundamental questions of science that we never could before but also translate it into the clinic for disease intervention."