New vaccine approach fights deadly melanoma
Researchers from the Mayo Clinic has successfully cured mice with melanoma in just a few months using a vaccine that includes a combination of DNA from human melanoma cells and a relative of the rabies virus.
The vaccine boosts the immune system to fight the deadly skin cancer with a strategy known as cancer immunotherapy. The researchers have discovered a way to target cancer tumors that normally hide to escape being destroyed that can also prevent cancer recurrence.
The rabies portion of the vaccine is a genetically engineered form of the vesicular stomatitis virus that serves as a way to deliver melanoma genes directly into cancer tumors.
According to the researchers the body is ‘trained’ by the vesicular stomatitis virus so that cancer cells can’t hide, which can often happen. Using a broad spectrum of DNA could also be used to treat other types of cancer.
Richard Vile, Ph.D., a Mayo Clinic researcher in the Department of Molecular Medicine and a coauthor of the study, along with Jose Pulido, M.D., a Mayo Clinic ophthalmologist and ocular oncologist discovered expressing different proteins in mice can leads to tumor rejection.
Vile said in a press release, "We believe that this new technique will help us to identify a whole new set of genes that encode antigens that are important in stimulating the immune system to reject cancer.”
Vile has also had success using DNA to destroy prostate tumors in mice. His team is currently using a vaccine to treat patients with liver cancer in a clinical trial and more vaccines may be coming for treatment of lung, pancreatic and brain cancer."I do believe we can create vaccines that will knock them off one by one," Dr. Vile says.
He adds, "Nobody knows how many antigens the immune system can really see on tumor cells. By expressing all of these proteins in highly immunogenic viruses, we increased their visibility to the immune system. The immune system now thinks it is being invaded by the viruses, which are expressing cancer-related antigens that should be eliminated."
The finding is a breakthrough because immunotherapy has been largely unsuccessful. Cancer cells keep mutate to thrive; escaping the immune system, often returning with a vengeance. Earlier studies showed 60% cure rates in mice with melanoma. The new study, published in the journal Nature Biotechnology, means there may be a future vaccine that can cure melanoma, using a new approach that can also prevent recurrence of the disease.
March 18, 2012
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