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New Nano-Beads Laced With Venom Slow Cancer Spread

Ker Than
for National Geographic News
April 17, 2009
 
They're not quite as efficient as Borg technology. But new "nanoprobes" made by combining scorpion venom with tiny metal beads are giving the fight against cancer a big performance boost.

Previous work had shown that chlorotoxin, a chemical derived from the giant Israeli scorpion, affects a protein on the outside of brain tumor cells called MMP-2. This protein is thought to help the cancer cells spread.

(Related: "Snake Venom May Slow Cancer Growth, Studies Hint.")

Chlorotoxin binds to MMP-2 like a key fitting in a lock. When the chemical latches on, both it and the protein get sucked into the cell.

Fewer MMP-2 sites on a cell surface make it harder for the cancer cell to travel to new regions in the brain.

In a new study, scientists chemically bonded iron oxide nanoparticles with a lab-made version of chlorotoxin to create tiny nanoprobes, each carrying up to 20 chlorotoxin molecules.

"So when a tumor cell uptakes a single nanoparticle, it is absorbing quite a few chlorotoxin molecules at once," said study leader Miqin Zhang of the University of Washington.

The researchers found that the nanoprobes can halt the spread of brain tumors in mice by 98 percent, compared to 45 percent with the scorpion venom alone.

A company called Transmolecular Inc. is already testing chlorotoxin by itself as a brain cancer therapy for humans.

But Zhang estimates that it may be another five to eight years before her team's nanoparticle-chlorotoxin cocktail might reach the clinical testing phase.

Findings published in the January 2009 issue of the journal Small.
 

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