MONDAY, June 20 (HealthDay News) -- Viral-expressed complementary DNA (cDNA) libraries may offer a novel way of treating cancer, according to an experimental study published online June 19 in Nature Medicine.
Timothy Kottke, from the Mayo Clinic in Rochester, Minn., and colleagues investigated whether a cDNA library of normal tissue, expressed from a highly immunogenic viral platform, could cure established tumors of the same histological type from which the cDNA library was derived. The investigators cloned a cDNA library from normal human prostate, expressing Altered Self Antigens/Epitopes from the library (ASEL) into vesicular stomatitis viruses (VSV) in direct or reverse orientations. VSV were cultured and introduced into the test mice as a vaccine against prostate tumor-associated antigen. A similar procedure was repeated with human B16 melanoma.
The investigators found that, within 10 days, the mice injected with ASEL had significantly lower prostate weights than controls with no trace of autoimmune disease. The ASEL had no effect against B16 melanomas. Similarly, a VSV-cDNA library from human melanoma cells significantly decreased murine B16 melanomas but had no effect on prostate tumors.
"Nobody really knows how many antigens the immune system can really see on tumor cells," says coauthor Dr. Richard Vile. "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."
Abstract
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