Scorpion Venom Might Help in Brain Cancer - Study
January 25, 1999 - 0:0
ANAHEIM, California The venom used by scorpions to paralyze their prey may offer a way to paralyze and kill off deadly brain tumors in people, a researcher said on Saturday. Harald Sontheimer of the University of Alabama said he and his colleagues isolated a substance from the scorpion venom that seems to act uniquely against brain-cancer cells. The researchers told the annual meeting of the American Association for the Advancement of Science that if the findings translate into humans something that will take years to test the toxin could offer the first real treatment for the deadly brain cancer known as glioma, which kills 18,000 Americans a year.
Sontheimer's team only has performed its work in test tubes and on mice. Scientists are wary of translating such experimental results into hopes for treating people. Scientists have discovered in recent years that components of animal poisons may be useful in treating human disease. For example, a compound found in the skin of Amazon poison-dart frogs can be used to treat pain if administered in tiny doses.
A protein found in snake poison, which causes victims to bleed to death, can, in smaller doses, stop blood from clotting and thus might be useful in treating heart disease and stroke. Sontheimer's team looked at the venom of the giant Israeli scorpion, a creature about five inches (12 cm) long. The researchers found it contains a peptide known as chlorotoxin that packs a specific action against brain-cancer cells.
Sontheimer, a neurobiologist, was trying to find approaches to treating glioma, a cancer of brain cells known as glial cells. There is no treatment for glioma besides surgery, and the tumors often spread throughout the brain very quickly, making it impossible to find and cut them all out. These cells are ready to set up shop after the (initial) tumor is removed, Sontheimer told a news conference.
His team looked specifically at ion channels, the chemical doorways that cells use to generate electric impulses, maintain fluid balance and other functions. It turns out that glial cancer cells have a unique ion channel, which involves the chemical chloride, researchers said. They use this channel to regulate the balance of fluid in the cell. By squeezing out some of the water, the tumor cells are able to shrink themselves and migrate through the dense mass of nerves that is the brain, researchers said.
The chlorotoxin peptide in the scorpion venom has an affinity for chloride channels. It homes in on them like a magnet and stops this shrinking process, researchers said. Sontheimer's team tried attaching radioactive iodine and plant poisons to the toxin to see if the toxin could be used to carry them into the tumors and kill them. It worked in the test tube and in mice that were specially engineered to develop gliomas, researchers said.
It only kills the bad cells, which suggests that if used in humans it will only kill the tumor in a very specific fashion, Sontheimer said. Mice do not develop brain cancers in the same way that humans do, so Sontheimer's team was not able to test whether the protein-poison combination actually could cure any person. But they are arranging to do those tests now.
Sontheimer said there also was evidence that the chlorotoxin might work against other cancers, but he declined to give details. There might be yet another use for the peptide. We know that this same peptide also paralyzes cockroaches, Sontheimer said jokingly. (Reuter)
Sontheimer's team only has performed its work in test tubes and on mice. Scientists are wary of translating such experimental results into hopes for treating people. Scientists have discovered in recent years that components of animal poisons may be useful in treating human disease. For example, a compound found in the skin of Amazon poison-dart frogs can be used to treat pain if administered in tiny doses.
A protein found in snake poison, which causes victims to bleed to death, can, in smaller doses, stop blood from clotting and thus might be useful in treating heart disease and stroke. Sontheimer's team looked at the venom of the giant Israeli scorpion, a creature about five inches (12 cm) long. The researchers found it contains a peptide known as chlorotoxin that packs a specific action against brain-cancer cells.
Sontheimer, a neurobiologist, was trying to find approaches to treating glioma, a cancer of brain cells known as glial cells. There is no treatment for glioma besides surgery, and the tumors often spread throughout the brain very quickly, making it impossible to find and cut them all out. These cells are ready to set up shop after the (initial) tumor is removed, Sontheimer told a news conference.
His team looked specifically at ion channels, the chemical doorways that cells use to generate electric impulses, maintain fluid balance and other functions. It turns out that glial cancer cells have a unique ion channel, which involves the chemical chloride, researchers said. They use this channel to regulate the balance of fluid in the cell. By squeezing out some of the water, the tumor cells are able to shrink themselves and migrate through the dense mass of nerves that is the brain, researchers said.
The chlorotoxin peptide in the scorpion venom has an affinity for chloride channels. It homes in on them like a magnet and stops this shrinking process, researchers said. Sontheimer's team tried attaching radioactive iodine and plant poisons to the toxin to see if the toxin could be used to carry them into the tumors and kill them. It worked in the test tube and in mice that were specially engineered to develop gliomas, researchers said.
It only kills the bad cells, which suggests that if used in humans it will only kill the tumor in a very specific fashion, Sontheimer said. Mice do not develop brain cancers in the same way that humans do, so Sontheimer's team was not able to test whether the protein-poison combination actually could cure any person. But they are arranging to do those tests now.
Sontheimer said there also was evidence that the chlorotoxin might work against other cancers, but he declined to give details. There might be yet another use for the peptide. We know that this same peptide also paralyzes cockroaches, Sontheimer said jokingly. (Reuter)