Bug Puts Sting in Cancer Fight
Posted on: 07/04/2002
Bug Puts Sting in Cancer Fight
By Delthia Ricks
July 4, 2002
Bugs are notorious for their bites, stings and downright dangers to human life, but an unusual new study is about to test whether a compound produced by scorpions is effective against brain tumors, scientists said yesterday.
Researchers at the City of Hope Cancer Center in Duarte, Calif., and the University of Alabama in Birmingham, are beginning an unusual regimen in which synthesized scorpion venom will be used in a clinical trial.
All of the patients are afflicted with a brain stem glioma, a type of tumor that can prove recalcitrant, and indeed is often referred to as one of the deadliest cancers known.
Dr. Adam Mamelak, a neurosurgeon and associate professor of neurosurgery at the cancer center, has begun recruiting patients for the first-ever treatment plan using venom derived from scorpions.
"The compound is a molecule, a small protein that is a synthetically manufactured version of a biologically active toxin found in a strain of scor- pions," Mamelak said. The venom is made synthetically because countless scorpions otherwise would be required.
Scorpions dine on small insects, Mamelak said, and use the compound in nature to paralyze their prey. The paralysis allows a scorpion time to slowly devour a meal without it moving.
Discovered by University of Alabama molecular biologist Harry Sontheimer, the compound has been dubbed 131I-TM-601 and is in the class of a growing number of cancer drugs called "targeted therapies." The first major drug in this class, Gleevec, approved last year, effectively treats rare forms of leukemia and stomach tumors by homing in on a chemical signal that goes awry in both cancers.
The scorpion compound was one of those serendipitous scientific discoveries that neither Sontheimer nor his University of Alabama colleagues expected. They have since formed a biotechnology company, TransMolecular Inc., in Birmingham, to synthetically produce the scorpion compound as a drug.
As a medication, Mamelak said, the compound zeroes in on a chemical signal on the surface of glioma cells. The venom changes the electrical activity of cancer cells and appears to halt their growth.
"What is amazing is that human brain tumor cells actually bind to this molecule," the doctor said of tumor cells clinging to and being deactivated by the bug-derived compound.
Studies of the scorpion secretion join a growing list of research projects focusing on the numerous substances bugs use to make love and war. Drugs from bugs are becoming an increasing reality as scientists explore numerous appli- cations that eventually could put bug- juice compounds on pharmacy shelves.
Researchers at Cornell University, for instance, have for years explored several bug secretions that are showing promise as antibiotics, cancer medications and drugs for heart disease.
Scorpions are generally found in warm regions of the country. The bugs have nipping claws and a long, slender jointed tail that ends in a curve.
Mamelak said the scorpion-derived compound will be tagged to radioactive iodine in the treatment plan for patients. Eighteen to 24 people with brain stem gliomas are being recruited.
In the lab, the scorpion secretion also appears to arrest the activity of melanoma cells, which are derived from a deadly form of skin cancer.
Copyright © 2002, Newsday, Inc.
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