Results of two-step therapy may further treatment for people with brain tumors

NEWS RELEASE
For immediate release

Contacts:
Mary Lawson, Masonic Cancer Center, 612-624-6165, mlawson@umn.edu
Molly Portz, Academic Health Center, 612-625-2640, mportz@umn.edu 

U of M develops experimental therapy for dog with fatal brain cancer
Results of two-step therapy may further treatment for people with brain tumors

MINNEAPOLIS/ST. PAUL (Aug. 6, 2008) Researchers with the University of Minnesota College of Veterinary Medicine, Medical School, and Masonic Cancer Center have successfully performed the first step of an experimental procedure to treat a dog with brain cancer. The team’s two-fold goal: cure or extend the life of the patient and gain information that will advance scientific knowledge about brain tumors for treatment of animals and humans with this disease.

The patient, a 10-year-old shepherd-mix dog named Batman (for his black, pointed ears that resemble the superhero) was diagnosed last week with a cancerous brain tumor which, left untreated, would have been fatal. His owners are Anna Brailovsky and Eric Baker of Minneapolis.

The August 5 three-hour procedure involved removal of as much of the brain tumor as possible, followed by the injection of a gene therapy around the perimeter of the tumor area. The injection serves to prime the remaining cancer cells for receiving a vaccine, which will be developed in the research laboratory using tumor tissue removed during surgery. In several weeks, the dog will be injected with the vaccine.

The procedure team included:

• Elizabeth Pluhar, D.V.M, Ph.D., performed the surgery. Pluhar specializes in veterinary orthopedics and neurosurgery at the College of Veterinary Medicine and conducts veterinary cancer research through the Masonic Cancer Center.
• Stephen Haines, M.D., a neurosurgeon at the University of Minnesota Medical Center, Fairview, who operates on humans diagnosed with brain tumors, assisted Pluhar with the surgery.
• John Ohlfest, Ph.D., provided the gene therapy and will create the vaccine. Ohlfest directs the University’s translational neurosurgery gene therapy program and conducts brain cancer research through the Masonic Cancer Center.

To date, research has involved separate investigations of the impact of gene therapy and vaccines on brain tumors. The University of Minnesota scientists and clinicians conducting this research think that surgery followed by combining the two experimental agents in one study -- a one-two punch of gene therapy followed by vaccine -- may have greater impact on the cancer. If this two-step process works, it could have significant importance for improving treatment for brain tumors in animals and people.

The gene therapy was a modified virus that cannot replicate and expresses the protein interferon gamma (IFN-g). IFN-g primed the tumor site, making the tumor cells more visible to Batman’s immune system.

"The problem with brain tumors is that they can hide from the immune system because the cancer cells typically don’t have surface proteins that allow the immune system to recognize and kill them," Ohlfest said. “IFN-g should reverse this, exposing the tumor to the immune system and allowing the vaccine to work at peak efficiency."

The tumor cells taken during the surgery will be killed in the laboratory to make one part of the vaccine. The other part of the vaccine will be an immunogenic portion of DNA derived from bacterial DNA called CpG ODN.

"The CpG ODN serves to trick the dog’s immune system into thinking it has a bacterial infection, only we will co-inject tumor cell proteins along with the CpG ODN so the immune system goes after the tumor with similar vigor that it would against bacteria," Ohlfest said. We expect that tumor-specific immune cells will then migrate into the brain to kill the remaining cancer cells."

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About the College of Veterinary Medicine
The College of Veterinary Medicine improves the health and well-being of animals and people by providing high-quality veterinary training, conducting leading-edge research, and delivering innovative veterinary services. For more information, visit www.cvm.umn.edu.
 
About the Masonic Cancer Center, University of Minnesota
The Masonic Cancer Center, University of Minnesota, is part of the University’s Academic Health Center. It is designated by the National Cancer Institute as a Comprehensive Cancer Center for cancer research, treatment, and education. For more information, visit www.cancer.umn.edu or call 612-624-2620.