Chlorotoxin is not the only venom-derived toxin being enlisted to disrupt cancer cells. Researchers from Washington University's Siteman Centre of Cancer Nanotechnology Excellence in St. Louis, Mo. have isolated the bee venom toxin melittin, which has been shown to cause tumor cell apoptosis -- cellular suicide.

Dr. Gregory Lanza, professor of medicine and biomedical engineering at Washington University School of Medicine, is a co-investigator on this project.

"Nobody really understands how it works," says Dr. Lanza. "It could be that it induces a better immune response, or it could be antiangiogenesis - it has had some of that effect in some models, or it could be that it's doing something we don't even understand yet."

Angiogenesis is the formation of new blood vessels. Typically there is a frenzy of new vessel formation happening at the growth front of a tumor. Dr. Lanza is principal researcher on another project involving nanodrugs that can halt angiogenesis with the help of a homing ligand isolated from a species of mold called fumagillin. A recent study resulted in an 80% reduction in tumor volume after treatment in rabbits.

Bamboo fungus leads to nano-radiotherapy

At the University of Alberta, Dr. Chen and his colleagues have developed a form of nano-radiotherapy that could one day replace traditional radiation treatments.

"Radiation therapy is like a B-50 bomber - it bombs the whole area. Nano treatment is quite the opposite," says Dr. Chen. "We can specifically target the cells you want to treat. We still use a bomb, but this is like a very small bomb with a GPS system."

A compound naturally occurring in a bamboo-borne fungus gets very excited in the presence of ultrasound. Cancer cells that have taken up nanoparticles conjugated with this compound undergo a kind of cellular radiotherapy.

"This specific bamboo fungus has a resonant frequency that is synchronous with the ultrasound range, which produces free radicals," says Dr. Chen. "The free radicals damage the cells by generating instantaneous radiation - it's basically radiotherapy on a minute scale. The electrons are like satellites and if you shine a certain light or ultrasound on them, it forces them to strike out of their orbit and cause damage to the surrounding DNA."

The bamboo in question grows only in China and Japan and the fungal compound may have originally been used for cosmetic hair removal. Eventually, the compound was found to have unique cancer-fighting properties and was applied in an ointment to suppress skin cancer. Researchers have now taken this compound and conjugated it with nanomaterials that make it water soluble and injectable and have attached either homing ligands that listen for cancer cells' internal clocks, called telomeres, which tick-tock toward infinity in malignant cells, but turn off in healthy cells, or they can attach glucose which is taken up to a greater degree by cancer cells due to their hyper-metabolism.

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