Researchers have combined optogenetics and immunotherapy to fight cancer in an animal model, according to a new study published in eLife. This new technique is called optogenetic immodulation.

Neuroscientists have been using light to study neurons in the brain for years, although this is the first time it has been used in the immune system. In neurons, the process involves genetically engineering cells resulting in nerve cells that react after exposure to a particular color of light.

The researchers from Texas A&M Health Science Center modified the technique of optogenetics so it would be effective against cancer cells. The immune system posed some challenges: immune cells don't use electrical impulses to communicate. Additionally, there were difficulties figuring out how to get light to reach immune cells located deep within the body. "One major bottleneck limiting in vivo optogenetics is the inability of existing optical tools to penetrate deep into the human tissue (the current blue-light based optogenetic tool can penetrate only a few millimeters in depth) and to deliver sufficient light to cells that are circulating in the body. To overcome this, we use a specialized type of nanoparticle that could turn the near-infrared light (penetrates 1-2 cm) into blue light, and then modulate the activity of genetically engineered immune cells," Yubin Zhou, Ph.D., assistant professor at the Center for Translation Cancer Research at the Texas A&M Health Science Center Institute of Biosciences & Technology, told ALN exclusively.

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This resulted in a method that controls and instructs immune cells to fight cancer cells. Genetically engineered cells open their calcium ion gates after exposure to a blue light. In mice, the near-infrared laser beam boosted an immune response to kill cancer cells by causing calcium channels to open. "In vivo, the NIR light therapy causes a remarkable reduction in the tumor size and tumor metastases in mouse melanoma models following photoactivation of engineered dendritic cells. Using near-infrared light, we can thus selectively activate an immune response by controlling the flow of calcium ions into the cell," Zhou added.

This new technique targets only certain types of immune cells, reducing the system-wide effects seen with chemotherapy. "This breakthrough could lead to less invasive, and more controlled and personalized immunotherapies for cancer treatment," Zhou continued.