Laboratory studies at Johns Hopkins have dramatically confirmed the power of a chemical discovered from the liver of sharks to slow the formation of new blood vessels destined to feed brain cancers as well as other tumors.
Squalamine, previously shown to have antibiotic and anti-cancer activity, inhibited the growth of brain cancers called gliomas implanted in the flanks of rats by disabling blood vessel growth, or angiogenesis, say the authors of the studies, published in the July 1 issue of the journal Cancer Research.
"Our results suggest that squalamine may be well suited for humans in the treatment of brain tumors and other diseases characterized by and dependent on new blood vessel growth," says Henry Brem, M.D., director of neurosurgical oncology at Hopkins and senior author of the study. "It dramatically slowed blood vessel formation without damaging healthy cells or embryonic development."
Named for the shark genus Squalus, squalamine was discovered in 1992 by scientists who founded Magainin Pharmaceuticals, which processes the chemical and funded the Hopkins studies. Squalamine is the first of a new class of naturally occurring molecules, aminosterols, under development for human therapies.
Squalamine is isolated from the tissues of the dog shark. It blocks or interferes with several steps in a cascade of events involved in blood vessel growth. Based on the Hopkins laboratory work, it is currently in Phase I clinical trials at the University of Texas (San Antonio) and at Georgetown Cancer Center.
In laboratory tests, squalamine proved to be as effective as the
chemotherapeutic agent carmustine in slowing the growth of gliomas, the most
common and deadly brain tumors, in rats. Squalamine also slowed the growth of
new blood vessels caused by tumors in rabbits' eyes, slowed the growth of
endothelial cells in rat brain tissue and constricted the tiny blood vessels in
chick embryos. The latter ves
Contact: Karen Infeld
Johns Hopkins Medical Institutions