Researchers from Hong Kong claim to have found a way eradicate mesothelioma in mice using a DNA vaccine. Microbiologists at the University of Hong Kong have even gone so far as to use the word “cure” in their recently-published paper in the journal Cancer Research.
Like other types of cancer, asbestos-induced mesothelioma spreads, in part, by suppressing the body’s natural anti-cancer defenses. The Hong Kong team administered a vaccine based on PD-1, a protein known as “programmed cell death protein 1”, to effectively reprogram the DNA of the lab mice, turning those natural defenses back on. According to the report, the PD-1-based DNA vaccine conferred “complete and long-lasting protection” against “lethal mesothelioma challenge” in the mice.
But the advantages did not stop there. Lead study author Dr. Zhiwu Tan of the AIDS Institute of Microbiology at the University of Hong Kong reports, “Furthermore, it remained highly immunogenic [immune-stimulating] in tumor-bearing animals and led to therapeutic cure of pre-existing mesothelioma.”
The vaccine appeared to work by stimulating the production of cancer-fighting CD8+ T cells. The larger the dose of vaccine, the better the protective effect against mesothelioma appeared to be. The researchers conclude that their findings have potentially important implications not only for mesothelioma but for other cancers, too. “Our results provide new insights into quantitative and qualitative requirements of vaccine-elicited functional CD8+ T cells in cancer prevention and immunotherapy,” writes Dr. Tan.
Although mesothelioma is an extremely rare cancer, it is also one of the most universally-fatal. Usually triggered by exposure to asbestos, mesothelioma kills an estimated 90,000 people around the world every year, including 2,500 in the U.S. In the absence of a reliable conventional treatment for mesothelioma, immune-based therapies like the PD-1 DNA vaccine are a major focus for mesothelioma researchers.
Tan, Z et al, “Vaccine-elicited CD8= T cells cure mesothelioma by overcoming tumor-induced immunosuppressive environment”, August 14, 2014, Cancer Researcher, Epub ahead of print