Doctors and patients dread a diagnosis of glioblastoma multiforme (GBM). The most common of all brain cancers, GBM tumors grow and travel fast. GBM resists standard treatments and is often fatal within a year.
Now researchers in Los Angeles report a new gene therapy that destroys GBM tumors in animals. The team, led by Maria Castro and Pedro Lowenstein of Cedars-Sinai Medical Center, described its findings Feb. 19 in an online edition of Molecular Therapy.
The key to the new therapy lies in attracting dendritic cells to the brain tumor. Dendritic cells are part of the body’s immune system. They latch on to proteins that don’t belong in the healthy body and “present them” to the immune system’s T and B cells, which then destroy the cancer cells.
The Cedars-Sinai team stripped a virus of its disease-causing genes and added two tumor-killing drugs to it. They also added a protein known to attract dendritic cells. When they injected the virus into rats that had the animal form of GBM, the virus “infected” the rats’ tumors, delivering the drugs and immune-attracting proteins to cancer cells.
In earlier research, the scientists had achieved a 20 percent survival rate using only the tumor-busting drugs in the carrier virus. In this new study, survival jumped to 70 percent. The animals ceased the abnormal movements that result from GBM, and the structure of their brains returned to normal.
The animals’ immune systems attacked and destroyed tumor cells and continued to do so, even when more tumor cells were introduced. “These findings are a significant milestone in creating an effective treatment for glioblastoma multiforme,” says Castro. Clinical trials in humans are possible later this year.