Researchers from the University of Georgia, along with researchers from the Mayo Clinic in Arizona, have developed a vaccine with the potential to fight breast cancer, and has implications for the treatment of ovarian, colorectal and pancreatic cancers, as well.
"This vaccine elicits a very strong immune response," study co-senior author Geert-Jan Boons, Franklin Professor of Chemistry and a researcher in the UGA Cancer Center and its Complex Carbohydrate Research Center said in a release. "It activates all three components of the immune system to reduce tumor size by an average of 80 percent."
The vaccine is targets cancers sharing the same distinct carbohydrate signature, study information in the Proceedings of the National Academy of Sciences indicates. Sugars on the surface of proteins are distinctly changed upon becoming cancerous. But, although they are then different from healthy cells, the immune system typically does not recognize them as foreign, because they originate within the body.
"This is the first time that a vaccine has been developed that trains the immune system to distinguish and kill cancer cells based on their different sugar structures on proteins such as MUC1," Sandra Gendler, Grohne Professor of Therapeutics for Cancer Research at the Mayo Clinic and co-senior author on the study, said. "We are especially excited about the fact that MUC1 was recently recognized by the National Cancer Institute as one of the three most important tumor proteins for vaccine development."
Gendler developed unique mice for the study. Mice, like humans, develop tumors that overexpress a protein known as MUC1 on the surface of their cells. The tumor-associated MUC1 protein is adorned with a distinctive, shorter set of carbohydrates that set it apart from healthy cells. MUC1 is found on more than 70 percent of all cancers that kill, Gendler said. Many cancers, in fact, express MUC1 with the shorter carbohydrate in more than 90 percent of cases, including breast, pancreatic, ovarian and multiple myeloma.
Boons noted that MUC1 also is overexpressed in 90 percent of the subset of patients who are not responsive to hormonal therapy, such as Tamoxifen or aromatase inhibitors, or the drug Herceptin. These so-called "triple-negative" tumors are extremely aggressive and difficult to treat, Boons said, and a new treatment option is urgently needed.
"In the U.S. alone, there are 35,000 patients diagnosed every year whose tumors are triple-negative," Boons said. "So we might have a therapy for a large group of patients for which there is currently no drug therapy aside from chemotherapy."
Boons, Gendler and their colleagues are currently testing the vaccine's effectiveness against human cancer cells in culture and are planning to assess its toxicity. If all goes well, they anticipate that phase I clinical trials to test the safety of the vaccine could begin by late 2013.
Image: University of Georgia