A type of plant virus that spreads to black-eyed pea plants has exhibited great effectiveness in combating metastatic cancers among mice.
Cowpea Mosaic Virus
The plant pathogen, known as cowpea mosaic virus, specializes in cowpeas, a legume species that includes the black-eyed peas subspecies.
This novel study is part of research led by nanoengineer Nicole Steinmetz's lab at the University of California, San Diego.
Steinmetz's team has spent years testing the nanoparticles of this virus as immunomodulators, which are substances that could stimulate or suppress the immune system.
Plant Virus Combats Mouse Cancers
Nanoparticles taken from the cowpea mosaic virus enhanced survival rates and suppressed tumor growth in mice with various cancers. These cancer types included ovarian, colon, and breast cancer.
The researchers also found that mice that underwent the surgical removal of their tumors exhibited notable improvements post-treatment.
The pathogen does not attack cancer cells in mice directly. Rather, it serves as an immunotherapy, which could help the body's immune system detect and destroy cancer.
The findings were documented in the "Systemic Administration of Cowpea Mosaic Virus Demonstrates Broad Protection Against Metastatic Cancers" study.
Previously, the nanoparticles have exhibited the potential to foster an immune response when directly injected into a tumor. The results of such efforts suggest that the treatment could prevent the spread and recurrence of cancer.
Researchers say that the virus cannot infect mammals because it is a plant pathogen. However, mice's immune systems tend to identify it as foreign.
This triggers the immune system to engage in a backlash. The system is also prompted to attack the nearby tumor and any future tumors that could spur.
However, there appears to be more to it. The study suggests that direct injection into the tumors is unnecessary for the nanoparticles to succeed. They may also be systematically delivered to impede metastasis and boost the survival range for various cancers.
Steinmetz notes that they prevent their formation rather than treating established metastatic conditions or tumors. They offer a systemic treatment that wakes up the body's immune system to eliminate the disease prior to the formation and settlement of the metastases.
The researchers started the new study by working on plants in the lab and infecting them with the virus. The pathogen then replicated independently, producing millions of novel copies for collection.
Steinmetz explains that the nanoparticles were suitable for mouse administration and did not need modification. The nanoparticles were then injected into the mice. The researchers then challenged the mice with metastatic tumors after a week, with the tumors including ovarian cancer, colon cancer, breast cancer, and melanoma.
Compared with untreated mice, the mice that received the treatment appeared to have boosted survival rates and lower growth of tumors. This was also observed a month later when new tumors were there to challenge the mice. The mice that received cowpea mosaic virus nanoparticles appeared to fare remarkably better.
The study also tested the effectiveness of the nanoparticles after tumor-removal surgery. It also revealed higher rates of survival and less growth of tumors among the mice that were treated.
Whether such a method would work on humans remains to be seen. Nevertheless, the study is still a promising step forward.
Future studies may aim to reveal the mechanisms behind the study results and establish the safety of the treatment among other animals. This could eventually pave the way for clinical trials to be conducted among humans.
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