Nanoengineers at the University of California San Diego discovered a novel therapy that uses a virus that develops in black-eyed pea plants to block metastatic tumors from spreading to the lungs.
The therapy not only delayed tumor development in the lungs of mice with metastatic breast cancer or melanoma, but it also prevented or significantly reduced the spread of these malignancies to the lungs of healthy mice confronted with the disease.
Cancer metastasis to the lungs is one of the most prevalent types of cancer metastasis. It is very dangerous and difficult to treat once it has entered the body.
Researchers at the University of California, San Diego’s Jacobs School of Engineering have devised an experimental therapy to fight the development of this disease. A plant virus known as the cowpea mosaic virus is injected into the body. Although the virus is safe to both animals and people, it nevertheless registers as a foreign intruder, prompting an immune response that may help the body fight cancer more effectively.
The goal is to employ the plant virus to aid the immune system’s recognition and destruction of cancer cells in the lungs. According to Nicole Steinmetz, professor of nanoengineering at UC San Diego and director of the university’s Center for Nano-ImmunoEngineering, the virus is not infectious in our bodies, but it sends out all these warning signals that cause immune cells to go into attack mode and look for a pathogen.
Steinmetz’s team used nanoparticles produced from the cowpea mosaic virus to target a protein in the lungs in order to elicit this immune response against lung tumors. Immune cells that aid in the fight against infection in the lungs produce and release the protein known as S100A9. Overexpression of S100A9 has been shown to have a role in tumor development and dissemination, which prompted Steinmetz’s team to focus on it.
“We need to direct our nanoparticles to the lung to make our immunotherapy function in the situation of lung metastasis,” Steinmetz explained. “As a result, we used S100A9 as the target protein to make these plant virus nanoparticles that would target the lungs. The nanoparticles in the lungs attract immune cells, preventing malignancies from taking hold.”
“Because these nanoparticles tend to localize in the lungs, they can change the tumor microenvironment there to make it more adept at fighting cancer not just existing tumors, but future tumors as well,” said Eric Chung, a bioengineering Ph.D. student in Steinmetz’s lab and one of the paper’s co-first authors.
The researchers created the nanoparticles by growing black-eyed pea plants in the lab, infecting them with cowpea mosaic virus, then harvesting the virus as ball-shaped nanoparticles. The particles’ surfaces were then coated with S100A9-targeting compounds.
Both preventive and therapy trials were carried out by the researchers. They first put plant virus nanoparticles into the bloodstreams of healthy mice, then injected either triple negative breast cancer or melanoma cells into these mice. When compared to untreated mice, treated animals exhibited a significant reduction in cancer spreading to their lungs.
The nanoparticles were given to mice with a metastatic tumor in their lungs in the therapy experiments. These mice had fewer lung cancers and lived longer than the control animals.
The researchers point out that the results are surprising since they demonstrate effectiveness against very aggressive cancer cell types. Chung explained, “Any difference in survival or lung metastasis is quite striking.” “And the fact that we have such a high degree of prevention is just incredible.”
Such a therapy, according to Steinmetz, might be especially beneficial to patients who have had a malignant tumor removed. “It wouldn’t be intended as a preventative shot for lung cancers provided to everyone. It would instead be given to individuals who are at a high risk of their malignancies returning as a metastatic illness, which frequently presents in the lungs. This would protect their lungs from cancer metastasis,” she explained.
Researchers will need to conduct more extensive immunotoxicity and pharmacology tests before the proposed therapy can reach that point. Future research will look into combining this with additional therapies like chemotherapy, checkpoint inhibitors, or radiation.