Researchers at Mayo Clinic in Arizona (http://www.mayoclinic.org/arizona/) and the University of Georgia (UGA) have developed a vaccine that dramatically reduces tumors in a mouse model that mimics 90 percent of human breast and pancreatic cancer cases A including those that are resistant to common treatments.
The vaccine, described this week in the early edition of the journal Proceedings of the National Academy of Sciences (http://www.pnas.org/), reveals a promising new strategy for treating cancers that share the same distinct carbohydrate signature, including ovarian and colorectal cancers.
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.
“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,” Dr. Gendler says. “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.”
Dr. Gendler says 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 on more than 90 percent of cases.
Dr. Gendler and her colleagues are currently testing the vaccine’s effectiveness against human cancer cells in culture and are planning to assess toxicity. If all goes well, phase I clinical trials to test the safety of the vaccine could begin by late 2013.