Nanoparticles engineered from the cowpea mosaic virus have shown efficacy in treating and greatly reducing the spread of metastatic cancers in the lungs of mice
Using a virus that grows in black-eyed pea plants, nanoengineers at the University of California San Diego developed a new treatment that could keep metastatic cancers at bay from the lungs. The research was published in the journal Advanced Science. The approach involves a bodily injection of a plant virus called the cowpea mosaic virus. The idea is to use the plant virus to help the body’s immune system recognize and destroy cancer cells in the lungs. The virus itself is not infectious in our bodies, but it has all these danger signals that alarm immune cells to go into attack mode and search for a pathogen, said Nicole Steinmetz, professor of nanoengineering at UC San Diego and director of the university’s Center for Nano-ImmunoEngineering.
To draw this immune response to lung tumors, Steinmetz’s lab engineered nanoparticles made from the cowpea mosaic virus to target a protein in the lungs. The protein, called S100A9, is expressed and secreted by immune cells that help fight infection in the lungs. And there is another reason that motivated Steinmetz’s team to target this protein: overexpression of S100A9 has been observed to play a role in tumor growth and spread. “Because these nanoparticles tend to localize in the lungs, they can change the tumor microenvironment there to become more adept at fighting off cancer—not just established tumors, but future tumors as well,” said Eric Chung, a bioengineering Ph.D. student in Steinmetz’s lab who is one of the co-first authors on the paper.
The researchers performed both prevention and treatment studies. In the prevention studies, they first injected the plant virus nanoparticles into the bloodstreams of healthy mice, and then later injected either triple negative breast cancer or melanoma cells in these mice. Treated mice showed a dramatic reduction in the cancers spreading to their lungs compared to untreated mice. In the treatment studies, the researchers administered the nanoparticles to mice with metastatic tumor in their lungs. These mice exhibited smaller lung tumors and survived longer than untreated mice. What’s remarkable about these results, the researchers point out, is that they show efficacy against extremely aggressive cancer cell lines. “So, any change in survival or lung metastasis is pretty striking,” said Chung. “And the fact that we get the level of prevention that we do is really, really amazing.”
Source: University of California San Diego news release