Aug 22 2005
A compound that kills cancer can sneak past the blood brain barrier, which protects the brain from foreign substances, to do its work in fighting a particularly invasive brain cancer, according to a new Saint Louis University animal study published in the Proceedings of the National Academy of Sciences Online Early Edition the week of Aug. 22.
"The bottom line is, if you can get drugs into the brain, you can cure brain cancer," says William A. Banks, M.D., professor of geriatrics in the department of internal medicine and professor of pharmacological and physiological science at Saint Louis University School of Medicine and a member of the research team.
The compound – JV-1-36 – is an antagonist of the hypothalamic growth hormone- releasing hormone, which has been found to cause cancerous tumors, such as malignant glioblastomas, to grow. The main known purposes of the hypothalamic growth hormone-releasing hormone usually are to trigger the hormone that makes children grow and affect how glucose is used in adults.
Researchers found that the P-gp system, an extra guardian located at the blood brain barrier that usually keeps anticancer drugs out of the brain, intercepted some of the JV-1-36 that was injected into mice but let much of it pass into the brain to treat cancer.
"The blood brain barrier is set up to very carefully patrol what it lets into the brain and what it keeps out. It makes these decisions based on the physicochemical properties," says Dr. Banks, who also is a staff physician at Veterans Affairs Medical Center in St. Louis.
"Most of our drugs that fight cancers are toxic to cancer cells and to other cells, too. That's why the blood brain barrier locks them out of the brain."
The research was done in collaboration with investigators at Tulane University School of Medicine in New Orleans, including Nobel Laureate Andrew V. Schally, Ph.D.
Dr. Banks said the findings are promising because they show a way to get drugs into the brain to treat cancer.
"There are times when there's a big difference between an animal model and the human condition. In terms of getting drugs across the blood brain barrier to fight cancer, there's not such a big difference. There's pretty much the same rules in any blood brain barrier – be it in a mouse or human."
Laura Jaeger, the lead author of the study and a doctoral student in the department of pharmacological and physiological science at Saint Louis University, calls the findings "very positive and a good first step."