Researchers have developed a vaccine that dramatically reduces tumors in a mouse model that mimics 90 percent of human breast and pancreatic cancer cases-including those that are resistant to common treatments.
“This vaccine elicits a very strong immune response,” said 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. “It activates all three components of the immune system to reduce tumor size by an average of 80 percent.”
When cells become cancerous, the sugars on their surface proteins undergo distinct changes that set them apart from healthy cells. For decades, scientists have tried to enable the immune system to recognize those differences to destroy cancer cells rather than normal cells. But since cancer cells originate within the body, the immune system generally doesn’t recognize them as foreign and therefore doesn’t mount an attack.
The researchers used unique mice developed by Sandra Gendler, Grohne Professor of Therapeutics for Cancer Research at the Mayo Clinic in Arizona and co-senior author on the study. Like humans, the mice 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.
“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,” Gendler said.
Gendler pointed out that MUC1 is found on more than 70 percent of all cancers that kill. Many cancers, such as breast, pancreatic, ovarian and multiple myeloma, express MUC1 with the shorter carbohydrate in more than 90 percent of cases.
A vaccine directed against MUC1 has tremendous potential, Gendler said, as a preventative for recurrence or as a prophylactic in patients at high risk for particular cancers. A vaccine also can be used together with standard therapy such as chemotherapy in cancers that cannot be cured by surgery, such as pancreatic cancer.
Therapeutic vaccines received renewed attention last year when the Food and Drug Administration approved the first cancer treatment vaccine, a drug known as Provenge that is used to treat metastatic prostate cancer.
Boons’ vaccine consists of three components-an immune system booster known as an adjuvant, a component that triggers the production of the immune system’s T-helper cells, and a carbohydrate-linked peptide molecule that directs the immune response to cells bearing MUC1 proteins with truncated carbohydrates.
Biotechnology is a key industry in Georgia, and this year Boons founded an Athens-based company, known as Viamune, to help develop and commercialize the vaccine and the technologies used to create it. The company is one of nearly 30 that are affiliated with the University’s BioBusiness Center, which is an incubator for life sciences start-up companies associated with UGA.
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.
Source: University of Georgia, Georgia