Prostate cancer vaccine from virus expressed cDNA destroys tumors
Researchers from the Mayo Clinic and United Kingdom teamed up to develop a vaccine that was able to destroy prostate cancer in mice with no apparent side effects that are typical of chemotherapy. The prostate cancer vaccine boosts the immune system to rid itself of cancerous tumors.
Novel prostate cancer vaccine works in mice
Richard Vile, Ph.D., Mayo Clinic immunologist, Richard M. Schulze Family Foundation Professor and a lead author of the study, explains immunotherapy – using the body’s own defense to fight cancer – has been met with hurdles. The researchers hope the prostate cancer vaccine developed will eliminate some of the problems associated with cancer immunotherapy and problems associated with past efforts at finding cancer vaccines.
Immunotherapy for cancer primarily consists of administering interleukin-2 that can cause allergy, heart failure and thyroid or kidney problems. Interferons that also boost immunity can produce flu-like symptoms that can be severe, nausea, appetite loss and vomiting. Gene therapy is still being explored as a way to boost the body’s own defense against cancer, but there are safety considerations about introducing viruses and diseased cells into the body. Vaccine development has been difficult because it's hard to get the immune system to recognize cancer cells.
Antigens developed from cDNA libraries destroy prostate cancer
The researchers explain the vaccine works by producing antigens that attack prostate cancer tumor cells. They used healthy human prostate tissue inserted into a mutated virus to stimulate T-cells to attack cancer.
Dr. Vile developed a complementary DNA library (cDNA) from healthy human prostate tissue, and then inserted them into mutated vesicular stomatitis viruses (VSV) for use as a vaccine vector. The immune system recognized antigens from the virus in mouse studies, raising immune response to prostate cancer that the researchers say was potent.
Dr. Vile explained, “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.” He adds, “Nobody really knows how many antigens the immune system can really see on tumor cells,
In the past, finding diverse number of antigens has been difficult for effective vaccines against cancer. Using viruses helps the immune system recognize cancer, eliminating the need to isolate antigens in cancer cells.
The researchers also say they found no trace of auto-immune diseases in the mice given the prostate cancer vaccine. T-cells in the mice only attacked cancer cells, leaving healthy tissue unaffected.
Clinical trials for a prostate cancer vaccine are anticipated within two years. The new approach for prostate cancer treatment with a vaccine also shows promise for other types of cancer.
Nature Medicine (2011) doi:10.1038/nm.2390
"Broad antigenic coverage induced by vaccination with virus-based
cDNA libraries cures established tumors"
Timothy Kottke, Fiona Errington et al
Image credit: Wikimedia commons
Author: Giorgio Gonnella User:Ggonnell
This page is updated on April 23, 2013.